Type 2 diabetes is more common in men whose puberty took place early, a University of Gothenburg study shows. An association may also be seen between low age of puberty and an elevated risk of the disease, if it develops, requiring insulin treatment.
The present observation study, published in the journal Diabetologia, covers 30,697 men in Sweden born between 1945 and 1961. Data on their age of puberty and body mass index (BMI) before and after puberty were taken from a population-based epidemiological study, the BMI Epidemiology Study Gothenburg.
The underlying data comprised figures for the subjects’ BMI when they were 8 and 20 years old, and “age of puberty” was defined as the time of their fastest height increase — that is, in the middle of the adolescent growth spurt, at an average age of 14. In addition, national health data from Swedish registers were used. The average follow-up time was 30 years, starting from age 30.
In the whole group, there were 1,851 men — approximately 6 percent — who were diagnosed with type 2 diabetes during the follow-up period. The average age at diagnosis was just over 57 years, the age that, in this study, separates what are described as “early” and “late” type 2 diabetes.
Marked rise in risk
The present study neither establishes any causal connections nor explains any mechanisms connecting early puberty and type 2 diabetes. However, the results are clear and persist after adjustment for BMI in childhood.
The strongest association was between early puberty and early diagnosis of type 2 diabetes, which developed before age 57. For the one-quarter of study participants who had undergone puberty earliest (at roughly 9–13 years), the risk of falling ill was twice that for those at the highest age (roughly 15–18 years) when their puberty growth spurt took place, after adjustment for the participants’ BMI at age 8. The association between early puberty and early development of type 2 diabetes remained after adjustment for BMI at age 20.
The risk for late-onset type 2 diabetes (after the age of 57) was also elevated in the group of participants who had undergone early puberty, but this association was not as strong and did not persist after adjustment for BMI at age 20.
The fact that participants with an early puberty had a higher risk of insulin-treated type 2 diabetes, confirms the results. Information on insulin prescription was retrieved from the Swedish Prescribed Drug Register.
Continuous monitoring of height and weight
Associate Professor Jenny Kindblom, Professor Claes Ohlsson and colleagues at Sahlgrenska Academy, University of Gothenburg, conducted the study.
“Our conclusion is that early puberty may be seen as a new, independent risk factor for type 2 diabetes in men. The risk is obviously higher among those who went through puberty early, and we estimate that 15 percent fewer men who received the diagnosis during the study would have developed type 2 diabetes if they hadn’t undergone puberty so early,” Kindblom says.
“These findings strengthen the concept that early puberty is part of an adverse trajectory during childhood and adolescence, and that a high BMI both before and after puberty contributes. So, to identify and help more individuals, continuous height and weight checks are important — not just in childhood but in the teenage years too,” she concludes.