Finnish kids are hitting puberty at an earlier age than previous generations, adding to a growing body of evidence that the timing of puberty is changing throughout the western world. This trend has led the Finnish medical community to recommend puberty blockers for girls under eight who show signs of puberty.
Precocious puberty can stunt growth in adulthood, and girls who start menstruating early run a higher risk of developing breast cancer later in life.
Of the 370,000 seven to 12-year-olds living in Finland last year, 150 had received puberty blockers, up from 100 ten years ago, according to Statistics Finland.
To delay the onset of puberty, kids take injections of leuprorelin, a synthetic hormone also used to treat prostate and breast cancer as it suppresses sex hormones.
Child in adult body
In Finland it’s normal for 8 to 11-year-old kids to reach puberty, and for 12 to 13-year-old girls to get their periods. A century ago girls did not reach this developmental milestone until they were 15 or 16 years old.
But even though kids' bodies may be developing faster today, their minds are not.
”Physical puberty lasts about five years, and during this time the brain is undergoing its own development, resulting in several years of internal conflict,” Silja Kosola, a physician focusing on adolescent medicine, explained.
Early puberty also puts young girls at risk of falling victim to sexual abuse as their brains are still immature.
”Kids whose puberty begins early are also more likely to engage in risky sexual behaviours,” said Miila Halonen, an adolescent health specialist from the Family Federation, noting that an 11-year-old is at a very different cognitive stage than a 15-year-old.
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Obesity factor
Jarmo Jääskeläinen, a paediatric endocrinologist at Kuopio University Hospital, told Yle the number of evaluations done to assess early puberty has doubled in the past decade.
In addition to monitoring children’s growth spurts, which can indicate early onset puberty, physicians use blood tests and hand x-rays to determine if a child’s development is outpacing their chronological age.
Scientists have yet to reach a verdict on the causes of early puberty but have flagged improved nutrition and environmental chemicals as endocrine disruptors.
Breast growth in young girls is not necessarily a sign of early puberty, but an indicator of excess weight.
”Child obesity has quadrupled in Finland since the 1970s, leading many to link precocious puberty to obesity,” Antti Saari, a paediatrician at Kuopio University Hospital explained.
Finns today are bigger than earlier generations. In 2010, the country's medical authorities issued new child growth charts showing that teenagers today are five centimetres taller than their cohorts in the 1960s.