Measurement error in self-reported dietary intakes is known to bias the association between dieta... more Measurement error in self-reported dietary intakes is known to bias the association between dietary intake and a health outcome of interest such as risk of a disease. The association can be distorted further by mismeasured confounders, leading to invalid results and conclusions. It is, however, difficult to adjust for the bias in the association when there is no internal validation data. We proposed a method to adjust for the bias in the diet-disease association (hereafter, association), due to measurement error in dietary intake and a mismeasured confounder, when there is no internal validation data. The method combines prior information on the validity of the self-report instrument with the observed data to adjust for the bias in the association. We compared the proposed method with the method that ignores the confounder effect, and with the method that ignores measurement errors completely. We assessed the sensitivity of the estimates to various magnitudes of measurement error, e...
Background: Physical activity has been found to be associated with decreased risk of breast cance... more Background: Physical activity has been found to be associated with decreased risk of breast cancer in postmenopausal women in the majority of epidemiologic studies, but the association is inconsistent in premenopausal women. Methods: We studied the effect of physical activity at various ages on the incidence of breast cancer in 99,504 women from 30 to 49 years of age at enrollment in the Women's Lifestyle and Health Study, a prospective population-based cohort study in Norway and Sweden. Physical activity level on an ordinal scale at age 14, age 30, and age at enrollment, participation in competitive sports, as well as information on other covariates was obtained using a self-administered questionnaire. Complete follow-up with data on incident invasive breast cancer and mortality was collected by linkage to national registries. The relation between physical activity and time to breast cancer development was assessed using Cox proportional hazard models, controlling for potential confounders. Results: During an average 9.1 years of follow-up, there were 1,166 incident breast cancer cases. The mean age of the women was 41 years at enrollment, and the mean age at breast cancer diagnosis was 48 years. Compared to inactive women, women with higher levels of physical activity at enrollment had a similar risk of incident breast cancer (adjusted relative risk, 1.24 for vigorous activity compared with no activity; 95% CI, 0.85-1.82). Physical activity at age 30 or at age 14 also did not afford any significant protection from breast cancer, nor did a consistently high level of activity from younger ages to enrollment. Conclusions: We did not find evidence of a protective effect of physical activity on breast cancer risk in this group of primarily premenopausal women. (Cancer Epidemiol Biomarkers Prev
The risk of ovarian epithelial neoplasia following use of hormonal contraceptives (HC) was examin... more The risk of ovarian epithelial neoplasia following use of hormonal contraceptives (HC) was examined in data from the Norwegian-Swedish Women's Lifestyle and Health cohort including 103551 women aged 30-49 years in 1991-92. Follow-up through 2000 produced 214 incident cases of histologically confirmed epithelial ovarian neoplasias (135 invasive and 79 borderline cases). Using the Cox proportional hazard models, ever having used HC was associated with a decreased relative risk of epithelial ovarian cancer of 0.6 (95% CI 0.5-0.8). The effect of duration of HC use was convincing (P for trend <0.0001), and more important than age at start of use or time since first or last use. There was no significant difference between the effects of combined oral contraceptives and progestins-only contraceptives on risk (P=0.98). Similarly, there was no significant difference between the effects of ever use of HC on invasive and borderline ovarian neoplasia (P=0.37). In this cohort, use of HC seems to reduce the risk of epithelial ovarian neoplasia markedly and persistently in relation to the duration of use.
Http Dx Doi Org 10 1080 01635581 2014 847472, Nov 25, 2013
To our knowledge, no studies of associations between intake of whole grain (WHG) and survival of ... more To our knowledge, no studies of associations between intake of whole grain (WHG) and survival of colorectal cancer have been published, despite evidence that dietary fiber, and to some extent WHG, are associated with lower risk of colorectal cancer. Scandinavia is an area where the WHG consumption traditionally is high. We performed a case-only (N = 1119) study in the Scandinavian HELGA cohort of pre-diagnosis WHG intake (total WHG, WHG wheat, WHG rye, and WHG oats) and survival of colorectal cancer. Cox regression analyses were used to study the associations, both in categorical and continuous models, stratified by location (proximal, distal, rectum) and country. No evidence of an association was found, neither for total WHG intake (hazard ratio = 1.32, 95% confidence interval: 0.88-1.97 lowest vs. highest tertile, adjusted for age at diagnosis, metastasis status, smoking, folate, margarine, and energy), nor for specific grains. Prediagnosis consumption of WHG does not seem to improve survival of colorectal cancer in subjects diagnosed within this prospective population-based Scandinavian cohort.
Objective: 'The Norwegian Women and Cancer Study' (NOWAC) was created as a national population-ba... more Objective: 'The Norwegian Women and Cancer Study' (NOWAC) was created as a national population-based cohort study by taking advantage of the existing population registers in Norway. Thus, the women in the NOWAC study should be representative for the entire female population in the corresponding age-groups. The aim of this paper was to study the external validity of the cohort as a necessary premise for the estimation of population attributable risk. Methods: Between 1991 and 1997 women were sampled randomly from the national Central person registry in Norway. A total of 179,388 women were invited, of whom 102,443 can be included in the forthcoming follow-up analysis. The response-rates were around 60% in the age-groups 30-34 years till 55-59 years, while 44.7% responded among those aged 65-70 years. Information was collected by postal questionnaires. Follow-up information was based on linkage to national end-point registers with use of the unique national identification number given all Norwegians.
An association between coffee consumption and cancer has long been investigated. Coffee consumpti... more An association between coffee consumption and cancer has long been investigated. Coffee consumption among Norwegian women is high, thus this is a favorable population in which to study the impact of coffee on cancer incidence. Information on coffee consumption was collected from 91,767 women at baseline in the Norwegian Women and Cancer Study. These information were applied until follow-up information on coffee consumption, collected 6-8 years after baseline, became available. Multiple imputation was performed as a method for dealing with missing data. Multivariable Cox regression models were used to calculate hazard ratios (HR) for breast, colorectal, lung, and ovarian cancer, as well as cancer at any site. We observed a 17 % reduced risk of colorectal cancer (HR = 0.83, 95 % CI 0.70-0.98, p trend across categories of consumption = 0.10) and a 9 % reduced risk of cancer at any site (HR = 0.91, 95 % CI 0.86-0.97, p trend = 0.03) in women who drank more than 3 and up to 7 cups/day, c...
Background: There is substantial evidence that higher levels of activity reduce the risk of morta... more Background: There is substantial evidence that higher levels of activity reduce the risk of mortality, but several research questions remain about the protective effect of physical activity. We aimed to quantify the effect of physical activity on overall mortality in younger women and to assess the effect of past versus current activity. Methods: During 1991-1992, we enrolled 99,099 women, age 30 -49 years, from the entire country of Norway and one Swedish region, in a population-based cohort study. The women provided information on physical activity level at age 14 and 30 years and at enrollment, as well as information on other personal characteristics at enrollment. We achieved complete follow-up into 2003 using record linkages to nationwide registers. We used Cox proportional hazard models to calculate multivariate relative risks (RRs) of dying from any cause. Results: During an average 11.4 years of follow-up, 1,313 women died. Risk of death decreased with increasing physical activity at enrollment (5 categories; P for trend Ͻ0.0001) and was reduced by half in the highest compared with the lowest category (RR ϭ 0.46; 95% confidence intervals ϭ 0.33-0.65). This protective effect was
There is evidence that consumption of foods containing dietary fiber decreases the risk of colore... more There is evidence that consumption of foods containing dietary fiber decreases the risk of colorectal cancer (CRC). Whole grains contain dietary fiber, as well as a range of micronutrients and bioactive compounds, but the association between the consumption of whole grains and the risk of CRC remains less studied. The aim of the present study was to investigate the association between whole-grain bread consumption and CRC incidence among Norwegian women, using data from a prospective cohort study (the Norwegian Women and Cancer Study). Dietary intake was estimated from the food-frequency questionnaires of 78,254 women in the cohort (median age: 55 years), and these women were then followed up for CRC incidence. During the 9 years of median follow-up, 795 women were diagnosed with CRC (316 proximal, 193 distal, 218 rectal). Associations between whole-grain bread consumption and the risk of CRC (including colorectal subsites) were investigated using Cox proportional hazards regression models. When compared to the low consumption group, the hazard ratio for CRC was 0.89 (95% confidence interval (CI): 0.72-1.09) for the high consumption group and 0.86 (95% CI: 0.72-1.02) for the medium consumption group in a multivariable model. Overall, no association between whole-grain bread consumption and CRC was found.
Among European women, ovarian cancer is the fifth most common cancer. Smoking is an established r... more Among European women, ovarian cancer is the fifth most common cancer. Smoking is an established risk factor for mucinous tumors. We estimated the impact of smoking in Norwegian women using population attributable fractions (PAFs) of epithelial ovarian cancer (EOC), by invasiveness and by histological subtypes in the Norwegian Women and Cancer Study with an average of 13.2 years of follow-up. During >2 million person-years, a total of 915 incident EOC cases, of which 667 (73%) invasive and 248 (27%) borderline, were identified among 154,234 women aged 34-70 years at enrolment. Compared with never smokers, current smokers had a nonstatistically significant increased risk of mucinous tumors (hazard ratio [HR] = 1.67 [95% confidence interval, (CI), 0.96-2.96]) and more than twice statistically significant risk of borderline mucinous tumors (HR = 2.17 [95% CI, 1.06-4.45]). The corresponding PAF estimates were 16.5% for mucinous and 25% for borderline mucinous. We found that among middle-aged women, one in six mucinous tumors and one in four borderline mucinous tumors could have been prevented if women did not smoke.
Various food patterns have been associated with weight change in adults, but it is unknown which ... more Various food patterns have been associated with weight change in adults, but it is unknown which combinations of nutrients may account for such observations. We investigated associations between main nutrient patterns and prospective weight change in adults. This study includes 235,880 participants, 25-70 years old, recruited between 1992 and 2000 in 10 European countries. Intakes of 23 nutrients were estimated from country-specific validated dietary questionnaires using the harmonized EPIC Nutrient DataBase. Four nutrient patterns, explaining 67 % of the total variance of nutrient intakes, were previously identified from principal component analysis. Body weight was measured at recruitment and self-reported 5 years later. The relationship between nutrient patterns and annual weight change was examined separately for men and women using linear mixed models with random effect according to center controlling for confounders. Mean weight gain was 460 g/year (SD 950) and 420 g/year (SD 940) for men and women, respectively. The annual differences in weight gain per one SD increase in the pattern scores were as follows: principal component (PC) 1, characterized by nutrients from plant food sources, was inversely associated with weight gain in men (-22 g/year; 95 % CI -33 to -10) and women (-18 g/year; 95 % CI -26 to -11). In contrast, PC4, characterized by protein, vitamin B2, phosphorus, and calcium, was associated with a weight gain of +41 g/year (95 % CI +2 to +80) and +88 g/year (95 % CI +36 to +140) in men and women, respectively. Associations with PC2, a pattern driven by many micro-nutrients, and with PC3, a pattern driven by vitamin D, were less consistent and/or non-significant. We identified two main nutrient patterns that are associated with moderate but significant long-term differences in weight gain in adults.
Optimal starting point for antiretroviral treatment (ART) has been uncertain. Parallel group, sin... more Optimal starting point for antiretroviral treatment (ART) has been uncertain. Parallel group, single blind, randomised controlled study of adult HIV positive patients consulting at the Protestant Hospital, Ngaoundere, Cameroon in 2007-8. Simple randomisation of patients in WHO clinical stage 1-2 to start of ART early or deferred, i.e. when CD4 counts dropped below 350 versus 250 cells/mm(3), or when they reached clinical stage 3-4. Clinical follow-up every three months were offered for all patients. Main outcomes were clinical stage, CD4 differences and mortality. Of 424 consulting patients, most were excluded, mainly because they were already in WHO stage 3-4. Forty-four patients were randomised. In the 'early' group two patients died and five were lost to follow-up. In the 'deferred' group, six patients died and nine were lost to follow-up (Hazard ratio for death by early compared to deferred treatment 0.26, 95% confidence interval 0.05-1.29). Of the patients lost ...
The risk of ovarian epithelial neoplasia following use of hormonal contraceptives (HC) was examin... more The risk of ovarian epithelial neoplasia following use of hormonal contraceptives (HC) was examined in data from the Norwegian-Swedish Women's Lifestyle and Health cohort including 103551 women aged 30-49 years in 1991-92. Follow-up through 2000 produced 214 incident cases of histologically confirmed epithelial ovarian neoplasias (135 invasive and 79 borderline cases). Using the Cox proportional hazard models, ever having used HC was associated with a decreased relative risk of epithelial ovarian cancer of 0.6 (95% CI 0.5-0.8). The effect of duration of HC use was convincing (P for trend <0.0001), and more important than age at start of use or time since first or last use. There was no significant difference between the effects of combined oral contraceptives and progestins-only contraceptives on risk (P=0.98). Similarly, there was no significant difference between the effects of ever use of HC on invasive and borderline ovarian neoplasia (P=0.37). In this cohort, use of HC s...
Sickness absence is a growing public health problem in Norway and Denmark, with the highest absen... more Sickness absence is a growing public health problem in Norway and Denmark, with the highest absence rates being registered in Norway. We compared time trends in sickness absence patterns of municipal employees in the health and care sectors in Norway and Denmark. Data from 2004 to 2008 were extracted from the personnel registers of the municipalities of Kristiansand, Norway, and Aarhus, Denmark, for 3,181 and 8,545 female employees, respectively. Age-specific comparative statistics on sickness absence rates (number of calendar days of sickness absence/possible working days) and number of sick leave episodes were calculated for each year of the study period. There was an overall increasing trend in sickness absence rates in Denmark (P = 0.002), where rates were highest in the 20-29- (P = 0.01) and 50-59-year-old age groups (P = 0.03). Sickness absence rates in Norway were stable, except for an increase in the 20-29-year-old age group (P = 0.004). In both Norway and Denmark, the mean ...
Consumption of fruits and vegetables is associated with a lower overall mortality. The aim of thi... more Consumption of fruits and vegetables is associated with a lower overall mortality. The aim of this study was to identify causes of death through which this association is established. More than 450,000 participants from the European Prospective Investigation into Cancer and Nutrition study were included, of which 25,682 were reported deceased after 13 years of follow-up. Information on lifestyle, diet and vital status was collected through questionnaires and population registries. Hazard ratios (HR) with 95 % confidence intervals (95 % CI) for death from specific causes were calculated from Cox regression models, adjusted for potential confounders. Participants reporting consumption of more than 569 g/day of fruits and vegetables had lower risks of death from diseases of the Electronic supplementary material The online version of this article (circulatory (HR for upper fourth 0.85, 95 % CI 0.77-0.93), respiratory (HR for upper fourth 0.73, 95 % CI 0.59-0.91) and digestive system (HR for upper fourth 0.60, 95 % CI 0.46-0.79) when compared with participants consuming less than 249 g/day. In contrast, a positive association with death from diseases of the nervous system was observed. Inverse associations were generally observed for vegetable, but not for fruit consumption. Associations were more pronounced for raw vegetable consumption, when compared with cooked vegetable consumption. Raw vegetable consumption was additionally inversely associated with death from neoplasms and mental and behavioral disorders. The lower risk of death associated with a higher consumption of fruits and vegetables may be derived from inverse associations with diseases of the circulatory, respiratory and digestive system, and may depend on the preparation of vegetables and lifestyle factors.
International journal of cancer. Journal international du cancer, Jan 15, 2015
Prospective studies examining the association between coffee and tea consumption and gastric canc... more Prospective studies examining the association between coffee and tea consumption and gastric cancer risk have shown inconsistent results. We investigated the association between coffee (total, caffeinated and decaffeinated) and tea consumption and the risk of gastric cancer by anatomical site and histological type in the European Prospective Investigation into Cancer and Nutrition study. Coffee and tea consumption were assessed by dietary questionnaires at baseline. Adjusted hazard ratios (HRs) were calculated using Cox regression models. During 11.6 years of follow up, 683 gastric adenocarcinoma cases were identified among 477,312 participants. We found no significant association between overall gastric cancer risk and consumption of total coffee (HR 1.09, 95%-confidence intervals [CI]: 0.84-1.43; quartile 4 vs. non/quartile 1), caffeinated coffee (HR 1.14, 95%-CI: 0.82-1.59; quartile 4 vs. non/quartile 1), decaffeinated coffee (HR 1.07, 95%-CI: 0.75-1.53; tertile 3 vs. non/tertile...
Measurement error in self-reported dietary intakes is known to bias the association between dieta... more Measurement error in self-reported dietary intakes is known to bias the association between dietary intake and a health outcome of interest such as risk of a disease. The association can be distorted further by mismeasured confounders, leading to invalid results and conclusions. It is, however, difficult to adjust for the bias in the association when there is no internal validation data. We proposed a method to adjust for the bias in the diet-disease association (hereafter, association), due to measurement error in dietary intake and a mismeasured confounder, when there is no internal validation data. The method combines prior information on the validity of the self-report instrument with the observed data to adjust for the bias in the association. We compared the proposed method with the method that ignores the confounder effect, and with the method that ignores measurement errors completely. We assessed the sensitivity of the estimates to various magnitudes of measurement error, e...
Background: Physical activity has been found to be associated with decreased risk of breast cance... more Background: Physical activity has been found to be associated with decreased risk of breast cancer in postmenopausal women in the majority of epidemiologic studies, but the association is inconsistent in premenopausal women. Methods: We studied the effect of physical activity at various ages on the incidence of breast cancer in 99,504 women from 30 to 49 years of age at enrollment in the Women's Lifestyle and Health Study, a prospective population-based cohort study in Norway and Sweden. Physical activity level on an ordinal scale at age 14, age 30, and age at enrollment, participation in competitive sports, as well as information on other covariates was obtained using a self-administered questionnaire. Complete follow-up with data on incident invasive breast cancer and mortality was collected by linkage to national registries. The relation between physical activity and time to breast cancer development was assessed using Cox proportional hazard models, controlling for potential confounders. Results: During an average 9.1 years of follow-up, there were 1,166 incident breast cancer cases. The mean age of the women was 41 years at enrollment, and the mean age at breast cancer diagnosis was 48 years. Compared to inactive women, women with higher levels of physical activity at enrollment had a similar risk of incident breast cancer (adjusted relative risk, 1.24 for vigorous activity compared with no activity; 95% CI, 0.85-1.82). Physical activity at age 30 or at age 14 also did not afford any significant protection from breast cancer, nor did a consistently high level of activity from younger ages to enrollment. Conclusions: We did not find evidence of a protective effect of physical activity on breast cancer risk in this group of primarily premenopausal women. (Cancer Epidemiol Biomarkers Prev
The risk of ovarian epithelial neoplasia following use of hormonal contraceptives (HC) was examin... more The risk of ovarian epithelial neoplasia following use of hormonal contraceptives (HC) was examined in data from the Norwegian-Swedish Women&amp;amp;amp;amp;#39;s Lifestyle and Health cohort including 103551 women aged 30-49 years in 1991-92. Follow-up through 2000 produced 214 incident cases of histologically confirmed epithelial ovarian neoplasias (135 invasive and 79 borderline cases). Using the Cox proportional hazard models, ever having used HC was associated with a decreased relative risk of epithelial ovarian cancer of 0.6 (95% CI 0.5-0.8). The effect of duration of HC use was convincing (P for trend &amp;amp;amp;amp;lt;0.0001), and more important than age at start of use or time since first or last use. There was no significant difference between the effects of combined oral contraceptives and progestins-only contraceptives on risk (P=0.98). Similarly, there was no significant difference between the effects of ever use of HC on invasive and borderline ovarian neoplasia (P=0.37). In this cohort, use of HC seems to reduce the risk of epithelial ovarian neoplasia markedly and persistently in relation to the duration of use.
Http Dx Doi Org 10 1080 01635581 2014 847472, Nov 25, 2013
To our knowledge, no studies of associations between intake of whole grain (WHG) and survival of ... more To our knowledge, no studies of associations between intake of whole grain (WHG) and survival of colorectal cancer have been published, despite evidence that dietary fiber, and to some extent WHG, are associated with lower risk of colorectal cancer. Scandinavia is an area where the WHG consumption traditionally is high. We performed a case-only (N = 1119) study in the Scandinavian HELGA cohort of pre-diagnosis WHG intake (total WHG, WHG wheat, WHG rye, and WHG oats) and survival of colorectal cancer. Cox regression analyses were used to study the associations, both in categorical and continuous models, stratified by location (proximal, distal, rectum) and country. No evidence of an association was found, neither for total WHG intake (hazard ratio = 1.32, 95% confidence interval: 0.88-1.97 lowest vs. highest tertile, adjusted for age at diagnosis, metastasis status, smoking, folate, margarine, and energy), nor for specific grains. Prediagnosis consumption of WHG does not seem to improve survival of colorectal cancer in subjects diagnosed within this prospective population-based Scandinavian cohort.
Objective: 'The Norwegian Women and Cancer Study' (NOWAC) was created as a national population-ba... more Objective: 'The Norwegian Women and Cancer Study' (NOWAC) was created as a national population-based cohort study by taking advantage of the existing population registers in Norway. Thus, the women in the NOWAC study should be representative for the entire female population in the corresponding age-groups. The aim of this paper was to study the external validity of the cohort as a necessary premise for the estimation of population attributable risk. Methods: Between 1991 and 1997 women were sampled randomly from the national Central person registry in Norway. A total of 179,388 women were invited, of whom 102,443 can be included in the forthcoming follow-up analysis. The response-rates were around 60% in the age-groups 30-34 years till 55-59 years, while 44.7% responded among those aged 65-70 years. Information was collected by postal questionnaires. Follow-up information was based on linkage to national end-point registers with use of the unique national identification number given all Norwegians.
An association between coffee consumption and cancer has long been investigated. Coffee consumpti... more An association between coffee consumption and cancer has long been investigated. Coffee consumption among Norwegian women is high, thus this is a favorable population in which to study the impact of coffee on cancer incidence. Information on coffee consumption was collected from 91,767 women at baseline in the Norwegian Women and Cancer Study. These information were applied until follow-up information on coffee consumption, collected 6-8 years after baseline, became available. Multiple imputation was performed as a method for dealing with missing data. Multivariable Cox regression models were used to calculate hazard ratios (HR) for breast, colorectal, lung, and ovarian cancer, as well as cancer at any site. We observed a 17 % reduced risk of colorectal cancer (HR = 0.83, 95 % CI 0.70-0.98, p trend across categories of consumption = 0.10) and a 9 % reduced risk of cancer at any site (HR = 0.91, 95 % CI 0.86-0.97, p trend = 0.03) in women who drank more than 3 and up to 7 cups/day, c...
Background: There is substantial evidence that higher levels of activity reduce the risk of morta... more Background: There is substantial evidence that higher levels of activity reduce the risk of mortality, but several research questions remain about the protective effect of physical activity. We aimed to quantify the effect of physical activity on overall mortality in younger women and to assess the effect of past versus current activity. Methods: During 1991-1992, we enrolled 99,099 women, age 30 -49 years, from the entire country of Norway and one Swedish region, in a population-based cohort study. The women provided information on physical activity level at age 14 and 30 years and at enrollment, as well as information on other personal characteristics at enrollment. We achieved complete follow-up into 2003 using record linkages to nationwide registers. We used Cox proportional hazard models to calculate multivariate relative risks (RRs) of dying from any cause. Results: During an average 11.4 years of follow-up, 1,313 women died. Risk of death decreased with increasing physical activity at enrollment (5 categories; P for trend Ͻ0.0001) and was reduced by half in the highest compared with the lowest category (RR ϭ 0.46; 95% confidence intervals ϭ 0.33-0.65). This protective effect was
There is evidence that consumption of foods containing dietary fiber decreases the risk of colore... more There is evidence that consumption of foods containing dietary fiber decreases the risk of colorectal cancer (CRC). Whole grains contain dietary fiber, as well as a range of micronutrients and bioactive compounds, but the association between the consumption of whole grains and the risk of CRC remains less studied. The aim of the present study was to investigate the association between whole-grain bread consumption and CRC incidence among Norwegian women, using data from a prospective cohort study (the Norwegian Women and Cancer Study). Dietary intake was estimated from the food-frequency questionnaires of 78,254 women in the cohort (median age: 55 years), and these women were then followed up for CRC incidence. During the 9 years of median follow-up, 795 women were diagnosed with CRC (316 proximal, 193 distal, 218 rectal). Associations between whole-grain bread consumption and the risk of CRC (including colorectal subsites) were investigated using Cox proportional hazards regression models. When compared to the low consumption group, the hazard ratio for CRC was 0.89 (95% confidence interval (CI): 0.72-1.09) for the high consumption group and 0.86 (95% CI: 0.72-1.02) for the medium consumption group in a multivariable model. Overall, no association between whole-grain bread consumption and CRC was found.
Among European women, ovarian cancer is the fifth most common cancer. Smoking is an established r... more Among European women, ovarian cancer is the fifth most common cancer. Smoking is an established risk factor for mucinous tumors. We estimated the impact of smoking in Norwegian women using population attributable fractions (PAFs) of epithelial ovarian cancer (EOC), by invasiveness and by histological subtypes in the Norwegian Women and Cancer Study with an average of 13.2 years of follow-up. During &amp;amp;gt;2 million person-years, a total of 915 incident EOC cases, of which 667 (73%) invasive and 248 (27%) borderline, were identified among 154,234 women aged 34-70 years at enrolment. Compared with never smokers, current smokers had a nonstatistically significant increased risk of mucinous tumors (hazard ratio [HR] = 1.67 [95% confidence interval, (CI), 0.96-2.96]) and more than twice statistically significant risk of borderline mucinous tumors (HR = 2.17 [95% CI, 1.06-4.45]). The corresponding PAF estimates were 16.5% for mucinous and 25% for borderline mucinous. We found that among middle-aged women, one in six mucinous tumors and one in four borderline mucinous tumors could have been prevented if women did not smoke.
Various food patterns have been associated with weight change in adults, but it is unknown which ... more Various food patterns have been associated with weight change in adults, but it is unknown which combinations of nutrients may account for such observations. We investigated associations between main nutrient patterns and prospective weight change in adults. This study includes 235,880 participants, 25-70 years old, recruited between 1992 and 2000 in 10 European countries. Intakes of 23 nutrients were estimated from country-specific validated dietary questionnaires using the harmonized EPIC Nutrient DataBase. Four nutrient patterns, explaining 67 % of the total variance of nutrient intakes, were previously identified from principal component analysis. Body weight was measured at recruitment and self-reported 5 years later. The relationship between nutrient patterns and annual weight change was examined separately for men and women using linear mixed models with random effect according to center controlling for confounders. Mean weight gain was 460 g/year (SD 950) and 420 g/year (SD 940) for men and women, respectively. The annual differences in weight gain per one SD increase in the pattern scores were as follows: principal component (PC) 1, characterized by nutrients from plant food sources, was inversely associated with weight gain in men (-22 g/year; 95 % CI -33 to -10) and women (-18 g/year; 95 % CI -26 to -11). In contrast, PC4, characterized by protein, vitamin B2, phosphorus, and calcium, was associated with a weight gain of +41 g/year (95 % CI +2 to +80) and +88 g/year (95 % CI +36 to +140) in men and women, respectively. Associations with PC2, a pattern driven by many micro-nutrients, and with PC3, a pattern driven by vitamin D, were less consistent and/or non-significant. We identified two main nutrient patterns that are associated with moderate but significant long-term differences in weight gain in adults.
Optimal starting point for antiretroviral treatment (ART) has been uncertain. Parallel group, sin... more Optimal starting point for antiretroviral treatment (ART) has been uncertain. Parallel group, single blind, randomised controlled study of adult HIV positive patients consulting at the Protestant Hospital, Ngaoundere, Cameroon in 2007-8. Simple randomisation of patients in WHO clinical stage 1-2 to start of ART early or deferred, i.e. when CD4 counts dropped below 350 versus 250 cells/mm(3), or when they reached clinical stage 3-4. Clinical follow-up every three months were offered for all patients. Main outcomes were clinical stage, CD4 differences and mortality. Of 424 consulting patients, most were excluded, mainly because they were already in WHO stage 3-4. Forty-four patients were randomised. In the 'early' group two patients died and five were lost to follow-up. In the 'deferred' group, six patients died and nine were lost to follow-up (Hazard ratio for death by early compared to deferred treatment 0.26, 95% confidence interval 0.05-1.29). Of the patients lost ...
The risk of ovarian epithelial neoplasia following use of hormonal contraceptives (HC) was examin... more The risk of ovarian epithelial neoplasia following use of hormonal contraceptives (HC) was examined in data from the Norwegian-Swedish Women's Lifestyle and Health cohort including 103551 women aged 30-49 years in 1991-92. Follow-up through 2000 produced 214 incident cases of histologically confirmed epithelial ovarian neoplasias (135 invasive and 79 borderline cases). Using the Cox proportional hazard models, ever having used HC was associated with a decreased relative risk of epithelial ovarian cancer of 0.6 (95% CI 0.5-0.8). The effect of duration of HC use was convincing (P for trend <0.0001), and more important than age at start of use or time since first or last use. There was no significant difference between the effects of combined oral contraceptives and progestins-only contraceptives on risk (P=0.98). Similarly, there was no significant difference between the effects of ever use of HC on invasive and borderline ovarian neoplasia (P=0.37). In this cohort, use of HC s...
Sickness absence is a growing public health problem in Norway and Denmark, with the highest absen... more Sickness absence is a growing public health problem in Norway and Denmark, with the highest absence rates being registered in Norway. We compared time trends in sickness absence patterns of municipal employees in the health and care sectors in Norway and Denmark. Data from 2004 to 2008 were extracted from the personnel registers of the municipalities of Kristiansand, Norway, and Aarhus, Denmark, for 3,181 and 8,545 female employees, respectively. Age-specific comparative statistics on sickness absence rates (number of calendar days of sickness absence/possible working days) and number of sick leave episodes were calculated for each year of the study period. There was an overall increasing trend in sickness absence rates in Denmark (P = 0.002), where rates were highest in the 20-29- (P = 0.01) and 50-59-year-old age groups (P = 0.03). Sickness absence rates in Norway were stable, except for an increase in the 20-29-year-old age group (P = 0.004). In both Norway and Denmark, the mean ...
Consumption of fruits and vegetables is associated with a lower overall mortality. The aim of thi... more Consumption of fruits and vegetables is associated with a lower overall mortality. The aim of this study was to identify causes of death through which this association is established. More than 450,000 participants from the European Prospective Investigation into Cancer and Nutrition study were included, of which 25,682 were reported deceased after 13 years of follow-up. Information on lifestyle, diet and vital status was collected through questionnaires and population registries. Hazard ratios (HR) with 95 % confidence intervals (95 % CI) for death from specific causes were calculated from Cox regression models, adjusted for potential confounders. Participants reporting consumption of more than 569 g/day of fruits and vegetables had lower risks of death from diseases of the Electronic supplementary material The online version of this article (circulatory (HR for upper fourth 0.85, 95 % CI 0.77-0.93), respiratory (HR for upper fourth 0.73, 95 % CI 0.59-0.91) and digestive system (HR for upper fourth 0.60, 95 % CI 0.46-0.79) when compared with participants consuming less than 249 g/day. In contrast, a positive association with death from diseases of the nervous system was observed. Inverse associations were generally observed for vegetable, but not for fruit consumption. Associations were more pronounced for raw vegetable consumption, when compared with cooked vegetable consumption. Raw vegetable consumption was additionally inversely associated with death from neoplasms and mental and behavioral disorders. The lower risk of death associated with a higher consumption of fruits and vegetables may be derived from inverse associations with diseases of the circulatory, respiratory and digestive system, and may depend on the preparation of vegetables and lifestyle factors.
International journal of cancer. Journal international du cancer, Jan 15, 2015
Prospective studies examining the association between coffee and tea consumption and gastric canc... more Prospective studies examining the association between coffee and tea consumption and gastric cancer risk have shown inconsistent results. We investigated the association between coffee (total, caffeinated and decaffeinated) and tea consumption and the risk of gastric cancer by anatomical site and histological type in the European Prospective Investigation into Cancer and Nutrition study. Coffee and tea consumption were assessed by dietary questionnaires at baseline. Adjusted hazard ratios (HRs) were calculated using Cox regression models. During 11.6 years of follow up, 683 gastric adenocarcinoma cases were identified among 477,312 participants. We found no significant association between overall gastric cancer risk and consumption of total coffee (HR 1.09, 95%-confidence intervals [CI]: 0.84-1.43; quartile 4 vs. non/quartile 1), caffeinated coffee (HR 1.14, 95%-CI: 0.82-1.59; quartile 4 vs. non/quartile 1), decaffeinated coffee (HR 1.07, 95%-CI: 0.75-1.53; tertile 3 vs. non/tertile...
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Papers by Tonje Braaten