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Kauko Heikkilä

University of Helsinki, Department of Public Health/Fimm, Database Manager

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Worked as data manager in Finnis Twin Registry since 1983.Thesis on the possible association of pregnancy other birth time covariates with the proportion of left-handedness almost ready. Three papers on that theme published. I have recently retired from my work as a data manager in the Finnish Twin Research group, but as of today (August 2019) still continue to assist its efforts.
Supervisors: professor Matti Iivanainen, Dr. Eero Vuoksimaa, Dr Aulikki Saari-Kemppainen, and Dr Jari Haukka

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Antonietta Pepe

University of Bordeaux (France)

Ingrid Szilagyi

Erasmus University Rotterdam

Behrooz Moghadam

Elsje van Bergen

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Papers by Kauko Heikkilä

Genome-wide association study identifies 49 common genetic variants associated with handedness

Handedness, a consistent asymmetry in skill or use of the hands, has been studied extensively bec... more Handedness, a consistent asymmetry in skill or use of the hands, has been studied extensively because of its relationship with language and the over-representation of left-handers in some neurodevelopmental disorders. Using data from the UK Biobank, 23andMe and 32 studies from the International Handedness Consortium, we conducted the world's largest genome-wide association study of handedness (1,534,836 right-handed, 194,198 (11.0%) left-handed and 37,637 (2.1%) ambidextrous individuals). We found 42 genetic loci associated with left-handedness and seven associated with ambidexterity at genome-wide levels of significance (P < 5x10-8). Tissue enrichment analysis implicated the central nervous system and brain tissues including the hippocampus and cerebrum in the etiology of left-handedness. Pathways including regulation of microtubules, neurogenesis, axonogenesis and hippocampus morphology were also highlighted. We found suggestive positive genetic correlations between being l...

Education in Twins and Their Parents Across Birth Cohorts Over 100 years: An Individual-Level Pooled Analysis of 42-Twin Cohorts

Twin research and human genetics : the official journal of the International Society for Twin Studies, Oct 1, 2017

Whether monozygotic (MZ) and dizygotic (DZ) twins differ from each other in a variety of phenotyp... more Whether monozygotic (MZ) and dizygotic (DZ) twins differ from each other in a variety of phenotypes is important for genetic twin modeling and for inferences made from twin studies in general. We analyzed whether there were differences in individual, maternal and paternal education between MZ and DZ twins in a large pooled dataset. Information was gathered on individual education for 218,362 adult twins from 27 twin cohorts (53% females; 39% MZ twins), and on maternal and paternal education for 147,315 and 143,056 twins respectively, from 28 twin cohorts (52% females; 38% MZ twins). Together, we had information on individual or parental education from 42 twin cohorts representing 19 countries. The original education classifications were transformed to education years and analyzed using linear regression models. Overall, MZ males had 0.26 (95% CI [0.21, 0.31]) years and MZ females 0.17 (95% CI [0.12, 0.21]) years longer education than DZ twins. The zygosity difference became smaller ...

Genome-wide analysis identifies 12 loci influencing human reproductive behavior

Nature genetics, Dec 31, 2016

The genetic architecture of human reproductive behavior-age at first birth (AFB) and number of ch... more The genetic architecture of human reproductive behavior-age at first birth (AFB) and number of children ever born (NEB)-has a strong relationship with fitness, human development, infertility and risk of neuropsychiatric disorders. However, very few genetic loci have been identified, and the underlying mechanisms of AFB and NEB are poorly understood. We report a large genome-wide association study of both sexes including 251,151 individuals for AFB and 343,072 individuals for NEB. We identified 12 independent loci that are significantly associated with AFB and/or NEB in a SNP-based genome-wide association study and 4 additional loci associated in a gene-based effort. These loci harbor genes that are likely to have a role, either directly or by affecting non-local gene expression, in human reproduction and infertility, thereby increasing understanding of these complex traits.

Leisure-time physical inactivity and association with body mass index: a Finnish Twin Study with a 35-year follow-up

International journal of epidemiology, Feb 15, 2016

We investigated the stability and change of leisure-time physical inactivity in adult men and wom... more We investigated the stability and change of leisure-time physical inactivity in adult men and women during a 35-year follow-up. We also analysed the impact of long-term physical inactivity on the development of body mass index (BMI). In this population-based cohort study, 5254 Finnish twin individuals (59% women) participated in four surveys in 1975, 1981, 1990 and 2011. Mean age at baseline was 23.9 years. Individual long-term leisure-time physical activity (LTPA) was categorized into seven classes varying from 'persistently inactive' to 'persistently active'. We used the multivariate multilevel mixed-effects linear regression model and paired-sample t-test in the analyses. Co-twin control design was used for examining within-pair associations. Of men 11%, and of women 8%, were persistently inactive. Among both sexes, the mean BMI slope trajectories were steeper among the persistently inactive and those who became inactive than among those who were persistently acti...

Meta-analysis of 375,000 individuals identifies 38 susceptibility loci for migraine

Migraine is a debilitating neurological disorder affecting around 1 in 7 people worldwide, but it... more Migraine is a debilitating neurological disorder affecting around 1 in 7 people worldwide, but its molecular mechanisms remain poorly understood. Some debate exists over whether migraine is a disease of vascular dysfunction, or a result of neuronal dysfunction with secondary vascular changes. Genome-wide association (GWA) studies have thus far identified 13 independent loci associated with migraine. To identify new susceptibility loci, we performed the largest genetic study of migraine to date, comprising 59,674 cases and 316,078 controls from 22 GWA studies. We identified 45 independent single nucleotide polymorphisms (SNPs) significantly associated with migraine risk (P < 5 x 10-8) that map to 38 distinct genomic loci, including 28 loci not previously reported and the first locus identified on chromosome X. Furthermore, a subset analysis for migraine without aura (MO) identified seven of the same loci as from the full sample, whereas no loci reached genome-wide significance in ...

The association of noise sensitivity with music listening, training, and aptitude

Noise & health

After intensive, long-term musical training, the auditory system of a musician is specifically tu... more After intensive, long-term musical training, the auditory system of a musician is specifically tuned to perceive musical sounds. We wished to find out whether a musician's auditory system also develops increased sensitivity to any sound of everyday life, experiencing them as noise. For this purpose, an online survey, including questionnaires on noise sensitivity, musical background, and listening tests for assessing musical aptitude, was administered to 197 participants in Finland and Italy. Subjective noise sensitivity (assessed with the Weinstein's Noise Sensitivity Scale) was analyzed for associations with musicianship, musical aptitude, weekly time spent listening to music, and the importance of music in each person's life (or music importance). Subjects were divided into three groups according to their musical expertise: Nonmusicians (N = 103), amateur musicians (N = 44), and professional musicians (N = 50). The results showed that noise sensitivity did not depend o...

Medical, psychological and genetic aspects of noise sensitivity

The study was based on the Finnish Twin Cohort of same-sex twin pairs. In 1988 a questionnaire wa... more The study was based on the Finnish Twin Cohort of same-sex twin pairs. In 1988 a questionnaire was sent to twin pairs discordant for hypertension. 1495 individuals (688 men, 807 women) aged 31–88 years replied, including 573 twin pairs. 218 of the subjects lived in the Helsinki Metropolitan Area. Self-reported noise sensitivity, lifetime noise exposure and hypertension were obtained from the questionnaire study in 1988 and other somatic and psychological factors from the questionnaire study in 1981 for the same individuals. In addition, noise map information from the Helsinki Metropolitan Area and mortality follow-up 1989-2003 were used. To evaluate the stability and validity of noise sensitivity, a new questionnaire was sent in 2002 to a sample of the subjects who had replied to the 1988 questionnaire. Of all subjects 38 % were noise sensitive. Noise sensitive subjects reported transportation noise exposure outside the environmental noise map areas almost twice as often as non-sens...

A Bi-monthly Inter-disciplinary International Journal

Noise and Health

Noise sensitivity is considered to be a self-perceived indicator of vulnerability to stressors in... more Noise sensitivity is considered to be a self-perceived indicator of vulnerability to stressors in general and not noise alone. Multiple chemical sensitivity (MCS) has to some extent been accompanied by noise sensitivity, indicating a moderate correspondence between them. The aim of this study is to investigate if the Weinstein's Noise Sensitivity Scale and Quick Environmental Exposure and Sensitivity Inventory's (QEESI) Chemical Intolerance Subscale can differentiate noise sensitivity and MCS as different entities, and if there are overlaps in the characteristics of noise sensitivity and MCS. In 2002, 327 individuals (166 men, 161 women; age range 45 - 66 years) from the Finnish Twin Cohort answered a questionnaire on noise-related and MCS items. Somatic, psychological, and lifestyle factors were obtained through earlier questionnaires for the same individuals. Both confirmatory and exploratory factor analyses (CFA and EFA) of the questionnaire items on the Weinstein's N...

Directional dominance on stature and cognition in diverse human populations

Nature, 2015

Homozygosity has long been associated with rare, often devastating, Mendelian disorders, and Darw... more Homozygosity has long been associated with rare, often devastating, Mendelian disorders, and Darwin was one of the first to recognize that inbreeding reduces evolutionary fitness. However, the effect of the more distant parental relatedness that is common in modern human populations is less well understood. Genomic data now allow us to investigate the effects of homozygosity on traits of public health importance by observing contiguous homozygous segments (runs of homozygosity), which are inferred to be homozygous along their complete length. Given the low levels of genome-wide homozygosity prevalent in most human populations, information is required on very large numbers of people to provide sufficient power. Here we use runs of homozygosity to study 16 health-related quantitative traits in 354,224 individuals from 102 cohorts, and find statistically significant associations between summed runs of homozygosity and four complex traits: height, forced expiratory lung volume in one se...

The negative affect hypothesis of noise sensitivity

International journal of environmental research and public health, Jan 18, 2015

Some studies indicate that noise sensitivity is explained by negative affect, a dispositional ten... more Some studies indicate that noise sensitivity is explained by negative affect, a dispositional tendency to negatively evaluate situations and the self. Individuals high in such traits may report a greater sensitivity to other sensory stimuli, such as smell, bright light and pain. However, research investigating the relationship between noise sensitivity and sensitivity to stimuli associated with other sensory modalities has not always supported the notion of a common underlying trait, such as negative affect, driving them. Additionally, other explanations of noise sensitivity based on cognitive processes have existed in the clinical literature for over 50 years. Here, we report on secondary analyses of pre-existing laboratory (n = 74) and epidemiological (n = 1005) data focusing on the relationship between noise sensitivity to and annoyance with a variety of olfactory-related stimuli. In the first study a correlational design examined the relationships between noise sensitivity, nois...

The CODATwins Project: The Cohort Description of Collaborative Project of Development of Anthropometrical Measures in Twins to Study Macro-Environmental Variation in Genetic and Environmental Effects on Anthropometric Traits

Twin research and human genetics : the official journal of the International Society for Twin Studies, Jan 27, 2015

For over 100 years, the genetics of human anthropometric traits has attracted scientific interest... more For over 100 years, the genetics of human anthropometric traits has attracted scientific interest. In particular, height and body mass index (BMI, calculated as kg/m2) have been under intensive genetic research. However, it is still largely unknown whether and how heritability estimates vary between human populations. Opportunities to address this question have increased recently because of the establishment of many new twin cohorts and the increasing accumulation of data in established twin cohorts. We started a new research project to analyze systematically (1) the variation of heritability estimates of height, BMI and their trajectories over the life course between birth cohorts, ethnicities and countries, and (2) to study the effects of birth-related factors, education and smoking on these anthropometric traits and whether these effects vary between twin cohorts. We identified 67 twin projects, including both monozygotic (MZ) and dizygotic (DZ) twins, using various sources. We a...

Noise sensitivity modulates the auditory-cortex discrimination of sound feature changes

ABSTRACT Noise sensitivity refers to physiological and psychological internal states of any indiv... more ABSTRACT Noise sensitivity refers to physiological and psychological internal states of any individual, which increase the degree of reactivity to noise. There are only few studies on the neural mechanisms underlying noise sensitivity. Mismatch negativity (MMN) is a component of the auditory event-related potential (ERP), generated in the supratemporal lobe of the brain, that is elicited by any discriminable change in some repetitive aspect of the ongoing auditory stimulation. In this study, we recruited 61 healthy adult subjects (age range 19-46 years) and measured their MMN to several sound feature changes inserted in a music-like sequence and administered the noise sensitivity questionnaire. With the help of this method we studied how the neural discrimination of sound changes (as indexed by MMN) is associated with noise sensitivity (as indexed by the questionnaire). The results showed that noise sensitivity has an influence on MMN to sound changes in timbre, with smaller MMN responses in individuals with high noise-sensitivity scores than in those with low noise-sensitivity scores. The MMN latency to the rhythm deviant correlated with noise sensitivity, meaning that higher noise sensitivity corresponded to the faster MMN to the rhythm change.

Physical Activity, Fitness, Glucose Homeostasis, and Brain Morphology in Twins

Medicine & Science in Sports & Exercise, 2015

Purpose: The main aim of the present study (FITFATTWIN) was to investigate how physical activity ... more Purpose: The main aim of the present study (FITFATTWIN) was to investigate how physical activity level is associated with body composition, glucose homeostasis, and brain morphology in young adult male monozygotic twin pairs discordant for physical activity. Methods: From a population-based twin cohort, we systematically selected 10 young adult male monozygotic twin pairs (age range, 32-36 yr) discordant for leisure time physical activity during the past 3 yr. On the basis of interviews, we calculated a mean sum index for leisure time and commuting activity during the past 3 yr (3-yr LTMET index expressed as MET-hours per day). We conducted extensive measurements on body composition (including fat percentage measured by dual-energy x-ray absorptiometry), glucose homeostasis including homeostatic model assessment index and insulin sensitivity index (Matsuda index, calculated from glucose and insulin values from an oral glucose tolerance test), and whole brain magnetic resonance imaging for regional volumetric analyses. Results: According to pairwise analysis, the active twins had lower body fat percentage (P = 0.029) and homeostatic model assessment index (P = 0.031) and higher Matsuda index (P = 0.021) compared with their inactive co-twins. Striatal and prefrontal cortex (subgyral and inferior frontal gyrus) brain gray matter volumes were larger in the nondominant hemisphere in active twins compared with those in inactive co-twins, with a statistical threshold of P G 0.001. Conclusions: Among healthy adult male twins in their mid-30s, a greater level of physical activity is associated with improved glucose homeostasis and modulation of striatum and prefrontal cortex gray matter volume, independent of genetic background. The findings may contribute to later reduced risk of type 2 diabetes and mobility limitations.

Genetic component of noise sensitivity

Twin Research and Human Genetics, 2005

Harmonization of Neuroticism and Extraversion phenotypes across inventories and cohorts in the Genetics of Personality Consortium: an application of Item Response Theory

Behavior genetics, 2014

Mega- or meta-analytic studies (e.g. genome-wide association studies) are increasingly used in be... more Mega- or meta-analytic studies (e.g. genome-wide association studies) are increasingly used in behavior genetics. An issue in such studies is that phenotypes are often measured by different instruments across study cohorts, requiring harmonization of measures so that more powerful fixed effect meta-analyses can be employed. Within the Genetics of Personality Consortium, we demonstrate for two clinically relevant personality traits, Neuroticism and Extraversion, how Item-Response Theory (IRT) can be applied to map item data from different inventories to the same underlying constructs. Personality item data were analyzed in…

Midlife Sleep Characteristics Associated with Late Life Cognitive Function

Sleep, 2013

Previous studies with limited follow-up times have suggested that sleep-related traits are associ... more Previous studies with limited follow-up times have suggested that sleep-related traits are associated with an increased risk of incident dementia or cognitive decline. We investigated the association between midlife sleep characteristics and late life cognitive function. Design: A follow-up study with a median follow-up time of 22.5 (range 15.8-25.7) years assessing the association between midlife sleep characteristics and later cognitive function. Setting: Questionnaire data from 1981 were used in the assessment of sleep characteristics, use of hypnotics, and covariates at baseline. Between 1999 and 2007, participants were assigned a linear cognitive score with a maximum score of 51 based on a telephone interview (mean score 38.3, SD 6.1). Linear regression analyses were controlled for age, sex, education, ApoE genotype, and follow-up time. Participants: 2,336 members of the Finnish Twin cohort who were at least 65 years of age. Interventions: N/A. Measurements and Results: Baseline short (< 7 h/day) and long (> 8 h/day) sleepers had lower cognitive scores than participants sleeping 7-8 h/ day (β =-0.84, P = 0.014 and β =-1.66, P < 0.001, respectively). As compared to good sleep quality, poor or rather poor sleep quality was associated with a lower cognitive score (β =-1.00, P = 0.011). Also, the use of hypnotics ≥ 60 days per year was associated with poorer cognitive function (β =-1.92, P = 0.002). Conclusions: This is the first study indicating that midlife sleep length, sleep quality, and use of hypnotics are associated with late life cognitive function. Further confirmation is needed, but sleep-related characteristics may emerge as new risk factors for cognitive impairment.

The association of noise sensitivity with coronary heart and cardiovascular mortality among Finnish adults

Science of The Total Environment, 2007

The association of coronary heart and cardiovascular mortality with noise sensitivity was studied... more The association of coronary heart and cardiovascular mortality with noise sensitivity was studied. We also investigated how this association is affected by self-reported lifetime noise exposure. In 1988 a case-control study, based on the Finnish Twin Cohort, was carried out to investigate the relationship between noise and hypertension (n=1495). Potential confounders were obtained from questionnaire in 1981 for the same individuals. Data on deaths and causes of death were obtained from record linkage to the nationwide register of death certificates. All deaths that occurred among the study population during the 15 years of follow-up were classified as being due to all causes (n=382), to cardiovascular diseases (n=193), including the number of deaths due to coronary heart diseases (n=111) and to other causes than cardiovascular diseases (n=189). Cardiovascular mortality (Hazard ratio 1.80, 95% CI 1.07-3.04) was significantly increased among noise-sensitive women. Among men, there were no statistically significant effects. Noise sensitivity may be a risk factor for cardiovascular mortality in women.

Noise sensitivity and multiple chemical sensitivity scales: Properties in a population based epidemiological study

Noise and Health, 2012

Noise sensitivity is considered to be a self-perceived indicator of vulnerability to stressors in... more Noise sensitivity is considered to be a self-perceived indicator of vulnerability to stressors in general and not noise alone. Multiple chemical sensitivity (MCS) has to some extent been accompanied by noise sensitivity, indicating a moderate correspondence between them. The aim of this study is to investigate if the Weinstein's Noise Sensitivity Scale and Quick Environmental Exposure and Sensitivity Inventory's (QEESI) Chemical Intolerance Subscale can differentiate noise sensitivity and MCS as different entities, and if there are overlaps in the characteristics of noise sensitivity and MCS. In 2002, 327 individuals (166 men, 161 women; age range 45-66 years) from the Finnish Twin Cohort answered a questionnaire on noise-related and MCS items. Somatic, psychological, and lifestyle factors were obtained through earlier questionnaires for the same individuals. Both confirmatory and exploratory factor analyses (CFA and EFA) of the questionnaire items on the Weinstein's Noise Sensitivity Scale and QEESI's Chemical Intolerance Subscale indicated the presence of three factors-Noise Sensitivity, Chemical Sensitivity, and Ability to Concentrate factors-arising from the forming of two factors from the items of the Weinstein's scale. In the regression analyses, among all subjects, the Noise Sensitivity Factor was associated with neuroticism and smoking, and the Chemical Sensitivity Factor was associated with allergies and alcohol use. The study indicates that the Weinstein's Noise Sensitivity Scale and QEESI's Chemical Intolerance Subscale differentiate noise sensitivity and MCS as different entities.

Self-Report of Transportation Noise Exposure, Annoyance and Noise Sensitivity in Relation to Noise Map Information

Journal of Sound and Vibration, 2000

Self-report of noise exposure was compared with the information on noise maps while taking into a... more Self-report of noise exposure was compared with the information on noise maps while taking into account measures of self-reported annoyance and noise sensitivity. Self-report data were analyzed for 1495 subjects participating in a case-control study of hypertension from the Finnish Twin Cohort who had replied to a questionnaire in 1988. In addition, noise map information was included in analyses of the 218 study subjects living in the Metropolitan Area of Helsinki. The results show that: (1) In the factor analysis based on all subjects self-report of transportation noise exposure formed an own factor independent of the annoyance variables or noise sensitivity. Annoyance items loaded on to two di!erent factors termed nighttime and daytime annoyance. Noise sensitivity did not load to either of the factors of annoyance. For the subsample with noise map information, the results indicated that: (2) Noise sensitivity was independent of noise map information. (3) Subjects with high noise sensitivity reported more transportation noise exposure than subjects with low noise sensitivity and they reported aircraft, railway and road tra$c noise exposure outside the environmental noise map areas almost twice as often as non-sensitive subjects. (4) Noise map information and self-report of noise exposure were consistently associated when aircraft noise was considered. Self-report of noise related items may supplement noise map information in noise protection.

Noise Sensitivity and Disability Retirement

Journal of Occupational & Environmental Medicine, 2013

To analyze whether noise sensitivity increases the risk of disability pension (DP). Questionnaire... more To analyze whether noise sensitivity increases the risk of disability pension (DP). Questionnaire data of a sample of 706 Finnish twin individuals (age range, 31 to 65 years) with record linkage to information on DP during 16 years of follow-up were analyzed using individual and pairwise Cox proportional hazards models. Noise sensitivity increased the risk of DP (hazard ratio = 1.41; 95% confidence interval [CI]: 1.03 to 1.93) and DP due to musculoskeletal disorders (hazard ratio = 1.63; 95% CI: 1.00 to 2.66). In within-pair analyses, noise sensitivity increased the risk of DP: among all twin pairs, odds ratio was 1.80 (95% CI: 1.08 to 3.06). Noise sensitivity may be a potential risk factor for disability retirement. It is associated with DP independently of familial background and genetic factors.

Genome-wide association study identifies 49 common genetic variants associated with handedness

Handedness, a consistent asymmetry in skill or use of the hands, has been studied extensively bec... more Handedness, a consistent asymmetry in skill or use of the hands, has been studied extensively because of its relationship with language and the over-representation of left-handers in some neurodevelopmental disorders. Using data from the UK Biobank, 23andMe and 32 studies from the International Handedness Consortium, we conducted the world's largest genome-wide association study of handedness (1,534,836 right-handed, 194,198 (11.0%) left-handed and 37,637 (2.1%) ambidextrous individuals). We found 42 genetic loci associated with left-handedness and seven associated with ambidexterity at genome-wide levels of significance (P < 5x10-8). Tissue enrichment analysis implicated the central nervous system and brain tissues including the hippocampus and cerebrum in the etiology of left-handedness. Pathways including regulation of microtubules, neurogenesis, axonogenesis and hippocampus morphology were also highlighted. We found suggestive positive genetic correlations between being l...

Education in Twins and Their Parents Across Birth Cohorts Over 100 years: An Individual-Level Pooled Analysis of 42-Twin Cohorts

Twin research and human genetics : the official journal of the International Society for Twin Studies, Oct 1, 2017

Whether monozygotic (MZ) and dizygotic (DZ) twins differ from each other in a variety of phenotyp... more Whether monozygotic (MZ) and dizygotic (DZ) twins differ from each other in a variety of phenotypes is important for genetic twin modeling and for inferences made from twin studies in general. We analyzed whether there were differences in individual, maternal and paternal education between MZ and DZ twins in a large pooled dataset. Information was gathered on individual education for 218,362 adult twins from 27 twin cohorts (53% females; 39% MZ twins), and on maternal and paternal education for 147,315 and 143,056 twins respectively, from 28 twin cohorts (52% females; 38% MZ twins). Together, we had information on individual or parental education from 42 twin cohorts representing 19 countries. The original education classifications were transformed to education years and analyzed using linear regression models. Overall, MZ males had 0.26 (95% CI [0.21, 0.31]) years and MZ females 0.17 (95% CI [0.12, 0.21]) years longer education than DZ twins. The zygosity difference became smaller ...

Genome-wide analysis identifies 12 loci influencing human reproductive behavior

Nature genetics, Dec 31, 2016

The genetic architecture of human reproductive behavior-age at first birth (AFB) and number of ch... more The genetic architecture of human reproductive behavior-age at first birth (AFB) and number of children ever born (NEB)-has a strong relationship with fitness, human development, infertility and risk of neuropsychiatric disorders. However, very few genetic loci have been identified, and the underlying mechanisms of AFB and NEB are poorly understood. We report a large genome-wide association study of both sexes including 251,151 individuals for AFB and 343,072 individuals for NEB. We identified 12 independent loci that are significantly associated with AFB and/or NEB in a SNP-based genome-wide association study and 4 additional loci associated in a gene-based effort. These loci harbor genes that are likely to have a role, either directly or by affecting non-local gene expression, in human reproduction and infertility, thereby increasing understanding of these complex traits.

Leisure-time physical inactivity and association with body mass index: a Finnish Twin Study with a 35-year follow-up

International journal of epidemiology, Feb 15, 2016

We investigated the stability and change of leisure-time physical inactivity in adult men and wom... more We investigated the stability and change of leisure-time physical inactivity in adult men and women during a 35-year follow-up. We also analysed the impact of long-term physical inactivity on the development of body mass index (BMI). In this population-based cohort study, 5254 Finnish twin individuals (59% women) participated in four surveys in 1975, 1981, 1990 and 2011. Mean age at baseline was 23.9 years. Individual long-term leisure-time physical activity (LTPA) was categorized into seven classes varying from 'persistently inactive' to 'persistently active'. We used the multivariate multilevel mixed-effects linear regression model and paired-sample t-test in the analyses. Co-twin control design was used for examining within-pair associations. Of men 11%, and of women 8%, were persistently inactive. Among both sexes, the mean BMI slope trajectories were steeper among the persistently inactive and those who became inactive than among those who were persistently acti...

Meta-analysis of 375,000 individuals identifies 38 susceptibility loci for migraine

Migraine is a debilitating neurological disorder affecting around 1 in 7 people worldwide, but it... more Migraine is a debilitating neurological disorder affecting around 1 in 7 people worldwide, but its molecular mechanisms remain poorly understood. Some debate exists over whether migraine is a disease of vascular dysfunction, or a result of neuronal dysfunction with secondary vascular changes. Genome-wide association (GWA) studies have thus far identified 13 independent loci associated with migraine. To identify new susceptibility loci, we performed the largest genetic study of migraine to date, comprising 59,674 cases and 316,078 controls from 22 GWA studies. We identified 45 independent single nucleotide polymorphisms (SNPs) significantly associated with migraine risk (P < 5 x 10-8) that map to 38 distinct genomic loci, including 28 loci not previously reported and the first locus identified on chromosome X. Furthermore, a subset analysis for migraine without aura (MO) identified seven of the same loci as from the full sample, whereas no loci reached genome-wide significance in ...

The association of noise sensitivity with music listening, training, and aptitude

Noise & health

After intensive, long-term musical training, the auditory system of a musician is specifically tu... more After intensive, long-term musical training, the auditory system of a musician is specifically tuned to perceive musical sounds. We wished to find out whether a musician's auditory system also develops increased sensitivity to any sound of everyday life, experiencing them as noise. For this purpose, an online survey, including questionnaires on noise sensitivity, musical background, and listening tests for assessing musical aptitude, was administered to 197 participants in Finland and Italy. Subjective noise sensitivity (assessed with the Weinstein's Noise Sensitivity Scale) was analyzed for associations with musicianship, musical aptitude, weekly time spent listening to music, and the importance of music in each person's life (or music importance). Subjects were divided into three groups according to their musical expertise: Nonmusicians (N = 103), amateur musicians (N = 44), and professional musicians (N = 50). The results showed that noise sensitivity did not depend o...

Medical, psychological and genetic aspects of noise sensitivity

The study was based on the Finnish Twin Cohort of same-sex twin pairs. In 1988 a questionnaire wa... more The study was based on the Finnish Twin Cohort of same-sex twin pairs. In 1988 a questionnaire was sent to twin pairs discordant for hypertension. 1495 individuals (688 men, 807 women) aged 31–88 years replied, including 573 twin pairs. 218 of the subjects lived in the Helsinki Metropolitan Area. Self-reported noise sensitivity, lifetime noise exposure and hypertension were obtained from the questionnaire study in 1988 and other somatic and psychological factors from the questionnaire study in 1981 for the same individuals. In addition, noise map information from the Helsinki Metropolitan Area and mortality follow-up 1989-2003 were used. To evaluate the stability and validity of noise sensitivity, a new questionnaire was sent in 2002 to a sample of the subjects who had replied to the 1988 questionnaire. Of all subjects 38 % were noise sensitive. Noise sensitive subjects reported transportation noise exposure outside the environmental noise map areas almost twice as often as non-sens...

A Bi-monthly Inter-disciplinary International Journal

Noise and Health

Noise sensitivity is considered to be a self-perceived indicator of vulnerability to stressors in... more Noise sensitivity is considered to be a self-perceived indicator of vulnerability to stressors in general and not noise alone. Multiple chemical sensitivity (MCS) has to some extent been accompanied by noise sensitivity, indicating a moderate correspondence between them. The aim of this study is to investigate if the Weinstein's Noise Sensitivity Scale and Quick Environmental Exposure and Sensitivity Inventory's (QEESI) Chemical Intolerance Subscale can differentiate noise sensitivity and MCS as different entities, and if there are overlaps in the characteristics of noise sensitivity and MCS. In 2002, 327 individuals (166 men, 161 women; age range 45 - 66 years) from the Finnish Twin Cohort answered a questionnaire on noise-related and MCS items. Somatic, psychological, and lifestyle factors were obtained through earlier questionnaires for the same individuals. Both confirmatory and exploratory factor analyses (CFA and EFA) of the questionnaire items on the Weinstein's N...

Directional dominance on stature and cognition in diverse human populations

Nature, 2015

Homozygosity has long been associated with rare, often devastating, Mendelian disorders, and Darw... more Homozygosity has long been associated with rare, often devastating, Mendelian disorders, and Darwin was one of the first to recognize that inbreeding reduces evolutionary fitness. However, the effect of the more distant parental relatedness that is common in modern human populations is less well understood. Genomic data now allow us to investigate the effects of homozygosity on traits of public health importance by observing contiguous homozygous segments (runs of homozygosity), which are inferred to be homozygous along their complete length. Given the low levels of genome-wide homozygosity prevalent in most human populations, information is required on very large numbers of people to provide sufficient power. Here we use runs of homozygosity to study 16 health-related quantitative traits in 354,224 individuals from 102 cohorts, and find statistically significant associations between summed runs of homozygosity and four complex traits: height, forced expiratory lung volume in one se...

The negative affect hypothesis of noise sensitivity

International journal of environmental research and public health, Jan 18, 2015

Some studies indicate that noise sensitivity is explained by negative affect, a dispositional ten... more Some studies indicate that noise sensitivity is explained by negative affect, a dispositional tendency to negatively evaluate situations and the self. Individuals high in such traits may report a greater sensitivity to other sensory stimuli, such as smell, bright light and pain. However, research investigating the relationship between noise sensitivity and sensitivity to stimuli associated with other sensory modalities has not always supported the notion of a common underlying trait, such as negative affect, driving them. Additionally, other explanations of noise sensitivity based on cognitive processes have existed in the clinical literature for over 50 years. Here, we report on secondary analyses of pre-existing laboratory (n = 74) and epidemiological (n = 1005) data focusing on the relationship between noise sensitivity to and annoyance with a variety of olfactory-related stimuli. In the first study a correlational design examined the relationships between noise sensitivity, nois...

The CODATwins Project: The Cohort Description of Collaborative Project of Development of Anthropometrical Measures in Twins to Study Macro-Environmental Variation in Genetic and Environmental Effects on Anthropometric Traits

Twin research and human genetics : the official journal of the International Society for Twin Studies, Jan 27, 2015

For over 100 years, the genetics of human anthropometric traits has attracted scientific interest... more For over 100 years, the genetics of human anthropometric traits has attracted scientific interest. In particular, height and body mass index (BMI, calculated as kg/m2) have been under intensive genetic research. However, it is still largely unknown whether and how heritability estimates vary between human populations. Opportunities to address this question have increased recently because of the establishment of many new twin cohorts and the increasing accumulation of data in established twin cohorts. We started a new research project to analyze systematically (1) the variation of heritability estimates of height, BMI and their trajectories over the life course between birth cohorts, ethnicities and countries, and (2) to study the effects of birth-related factors, education and smoking on these anthropometric traits and whether these effects vary between twin cohorts. We identified 67 twin projects, including both monozygotic (MZ) and dizygotic (DZ) twins, using various sources. We a...

Noise sensitivity modulates the auditory-cortex discrimination of sound feature changes

ABSTRACT Noise sensitivity refers to physiological and psychological internal states of any indiv... more ABSTRACT Noise sensitivity refers to physiological and psychological internal states of any individual, which increase the degree of reactivity to noise. There are only few studies on the neural mechanisms underlying noise sensitivity. Mismatch negativity (MMN) is a component of the auditory event-related potential (ERP), generated in the supratemporal lobe of the brain, that is elicited by any discriminable change in some repetitive aspect of the ongoing auditory stimulation. In this study, we recruited 61 healthy adult subjects (age range 19-46 years) and measured their MMN to several sound feature changes inserted in a music-like sequence and administered the noise sensitivity questionnaire. With the help of this method we studied how the neural discrimination of sound changes (as indexed by MMN) is associated with noise sensitivity (as indexed by the questionnaire). The results showed that noise sensitivity has an influence on MMN to sound changes in timbre, with smaller MMN responses in individuals with high noise-sensitivity scores than in those with low noise-sensitivity scores. The MMN latency to the rhythm deviant correlated with noise sensitivity, meaning that higher noise sensitivity corresponded to the faster MMN to the rhythm change.

Physical Activity, Fitness, Glucose Homeostasis, and Brain Morphology in Twins

Medicine & Science in Sports & Exercise, 2015

Purpose: The main aim of the present study (FITFATTWIN) was to investigate how physical activity ... more Purpose: The main aim of the present study (FITFATTWIN) was to investigate how physical activity level is associated with body composition, glucose homeostasis, and brain morphology in young adult male monozygotic twin pairs discordant for physical activity. Methods: From a population-based twin cohort, we systematically selected 10 young adult male monozygotic twin pairs (age range, 32-36 yr) discordant for leisure time physical activity during the past 3 yr. On the basis of interviews, we calculated a mean sum index for leisure time and commuting activity during the past 3 yr (3-yr LTMET index expressed as MET-hours per day). We conducted extensive measurements on body composition (including fat percentage measured by dual-energy x-ray absorptiometry), glucose homeostasis including homeostatic model assessment index and insulin sensitivity index (Matsuda index, calculated from glucose and insulin values from an oral glucose tolerance test), and whole brain magnetic resonance imaging for regional volumetric analyses. Results: According to pairwise analysis, the active twins had lower body fat percentage (P = 0.029) and homeostatic model assessment index (P = 0.031) and higher Matsuda index (P = 0.021) compared with their inactive co-twins. Striatal and prefrontal cortex (subgyral and inferior frontal gyrus) brain gray matter volumes were larger in the nondominant hemisphere in active twins compared with those in inactive co-twins, with a statistical threshold of P G 0.001. Conclusions: Among healthy adult male twins in their mid-30s, a greater level of physical activity is associated with improved glucose homeostasis and modulation of striatum and prefrontal cortex gray matter volume, independent of genetic background. The findings may contribute to later reduced risk of type 2 diabetes and mobility limitations.

Genetic component of noise sensitivity

Twin Research and Human Genetics, 2005

Harmonization of Neuroticism and Extraversion phenotypes across inventories and cohorts in the Genetics of Personality Consortium: an application of Item Response Theory

Behavior genetics, 2014

Mega- or meta-analytic studies (e.g. genome-wide association studies) are increasingly used in be... more Mega- or meta-analytic studies (e.g. genome-wide association studies) are increasingly used in behavior genetics. An issue in such studies is that phenotypes are often measured by different instruments across study cohorts, requiring harmonization of measures so that more powerful fixed effect meta-analyses can be employed. Within the Genetics of Personality Consortium, we demonstrate for two clinically relevant personality traits, Neuroticism and Extraversion, how Item-Response Theory (IRT) can be applied to map item data from different inventories to the same underlying constructs. Personality item data were analyzed in…

Midlife Sleep Characteristics Associated with Late Life Cognitive Function

Sleep, 2013

Previous studies with limited follow-up times have suggested that sleep-related traits are associ... more Previous studies with limited follow-up times have suggested that sleep-related traits are associated with an increased risk of incident dementia or cognitive decline. We investigated the association between midlife sleep characteristics and late life cognitive function. Design: A follow-up study with a median follow-up time of 22.5 (range 15.8-25.7) years assessing the association between midlife sleep characteristics and later cognitive function. Setting: Questionnaire data from 1981 were used in the assessment of sleep characteristics, use of hypnotics, and covariates at baseline. Between 1999 and 2007, participants were assigned a linear cognitive score with a maximum score of 51 based on a telephone interview (mean score 38.3, SD 6.1). Linear regression analyses were controlled for age, sex, education, ApoE genotype, and follow-up time. Participants: 2,336 members of the Finnish Twin cohort who were at least 65 years of age. Interventions: N/A. Measurements and Results: Baseline short (< 7 h/day) and long (> 8 h/day) sleepers had lower cognitive scores than participants sleeping 7-8 h/ day (β =-0.84, P = 0.014 and β =-1.66, P < 0.001, respectively). As compared to good sleep quality, poor or rather poor sleep quality was associated with a lower cognitive score (β =-1.00, P = 0.011). Also, the use of hypnotics ≥ 60 days per year was associated with poorer cognitive function (β =-1.92, P = 0.002). Conclusions: This is the first study indicating that midlife sleep length, sleep quality, and use of hypnotics are associated with late life cognitive function. Further confirmation is needed, but sleep-related characteristics may emerge as new risk factors for cognitive impairment.

The association of noise sensitivity with coronary heart and cardiovascular mortality among Finnish adults

Science of The Total Environment, 2007

The association of coronary heart and cardiovascular mortality with noise sensitivity was studied... more The association of coronary heart and cardiovascular mortality with noise sensitivity was studied. We also investigated how this association is affected by self-reported lifetime noise exposure. In 1988 a case-control study, based on the Finnish Twin Cohort, was carried out to investigate the relationship between noise and hypertension (n=1495). Potential confounders were obtained from questionnaire in 1981 for the same individuals. Data on deaths and causes of death were obtained from record linkage to the nationwide register of death certificates. All deaths that occurred among the study population during the 15 years of follow-up were classified as being due to all causes (n=382), to cardiovascular diseases (n=193), including the number of deaths due to coronary heart diseases (n=111) and to other causes than cardiovascular diseases (n=189). Cardiovascular mortality (Hazard ratio 1.80, 95% CI 1.07-3.04) was significantly increased among noise-sensitive women. Among men, there were no statistically significant effects. Noise sensitivity may be a risk factor for cardiovascular mortality in women.

Noise sensitivity and multiple chemical sensitivity scales: Properties in a population based epidemiological study

Noise and Health, 2012

Noise sensitivity is considered to be a self-perceived indicator of vulnerability to stressors in... more Noise sensitivity is considered to be a self-perceived indicator of vulnerability to stressors in general and not noise alone. Multiple chemical sensitivity (MCS) has to some extent been accompanied by noise sensitivity, indicating a moderate correspondence between them. The aim of this study is to investigate if the Weinstein's Noise Sensitivity Scale and Quick Environmental Exposure and Sensitivity Inventory's (QEESI) Chemical Intolerance Subscale can differentiate noise sensitivity and MCS as different entities, and if there are overlaps in the characteristics of noise sensitivity and MCS. In 2002, 327 individuals (166 men, 161 women; age range 45-66 years) from the Finnish Twin Cohort answered a questionnaire on noise-related and MCS items. Somatic, psychological, and lifestyle factors were obtained through earlier questionnaires for the same individuals. Both confirmatory and exploratory factor analyses (CFA and EFA) of the questionnaire items on the Weinstein's Noise Sensitivity Scale and QEESI's Chemical Intolerance Subscale indicated the presence of three factors-Noise Sensitivity, Chemical Sensitivity, and Ability to Concentrate factors-arising from the forming of two factors from the items of the Weinstein's scale. In the regression analyses, among all subjects, the Noise Sensitivity Factor was associated with neuroticism and smoking, and the Chemical Sensitivity Factor was associated with allergies and alcohol use. The study indicates that the Weinstein's Noise Sensitivity Scale and QEESI's Chemical Intolerance Subscale differentiate noise sensitivity and MCS as different entities.

Self-Report of Transportation Noise Exposure, Annoyance and Noise Sensitivity in Relation to Noise Map Information

Journal of Sound and Vibration, 2000

Self-report of noise exposure was compared with the information on noise maps while taking into a... more Self-report of noise exposure was compared with the information on noise maps while taking into account measures of self-reported annoyance and noise sensitivity. Self-report data were analyzed for 1495 subjects participating in a case-control study of hypertension from the Finnish Twin Cohort who had replied to a questionnaire in 1988. In addition, noise map information was included in analyses of the 218 study subjects living in the Metropolitan Area of Helsinki. The results show that: (1) In the factor analysis based on all subjects self-report of transportation noise exposure formed an own factor independent of the annoyance variables or noise sensitivity. Annoyance items loaded on to two di!erent factors termed nighttime and daytime annoyance. Noise sensitivity did not load to either of the factors of annoyance. For the subsample with noise map information, the results indicated that: (2) Noise sensitivity was independent of noise map information. (3) Subjects with high noise sensitivity reported more transportation noise exposure than subjects with low noise sensitivity and they reported aircraft, railway and road tra$c noise exposure outside the environmental noise map areas almost twice as often as non-sensitive subjects. (4) Noise map information and self-report of noise exposure were consistently associated when aircraft noise was considered. Self-report of noise related items may supplement noise map information in noise protection.

Noise Sensitivity and Disability Retirement

Journal of Occupational & Environmental Medicine, 2013

To analyze whether noise sensitivity increases the risk of disability pension (DP). Questionnaire... more To analyze whether noise sensitivity increases the risk of disability pension (DP). Questionnaire data of a sample of 706 Finnish twin individuals (age range, 31 to 65 years) with record linkage to information on DP during 16 years of follow-up were analyzed using individual and pairwise Cox proportional hazards models. Noise sensitivity increased the risk of DP (hazard ratio = 1.41; 95% confidence interval [CI]: 1.03 to 1.93) and DP due to musculoskeletal disorders (hazard ratio = 1.63; 95% CI: 1.00 to 2.66). In within-pair analyses, noise sensitivity increased the risk of DP: among all twin pairs, odds ratio was 1.80 (95% CI: 1.08 to 3.06). Noise sensitivity may be a potential risk factor for disability retirement. It is associated with DP independently of familial background and genetic factors.