Early Puberty in Men Linked to Increased Risk of Type 2 Diabetes in Middle Age

By Lisa Rapaport

March 25, 2020

(Reuters Health) - Boys who enter puberty at an earlier age are more likely to develop type 2 diabetes as adults, irrespective of weight in childhood, a study of more than 30,000 men in Sweden suggests.

After adjusting for childhood BMI, researchers found that men who reached peak height velocity (PHV) - an objective proxy for pubertal transition - earlier, meaning from 9.3 to 13.4 years of age, were twice as likely to develop type 2 diabetes by their mid-50s compared to men with PHV at 14.8 to 17.9 years.

Early age at PHV also predicted insulin treatment of type 2 diabetes (OR 1.25 per year decrease in age at PHV), the authors report in Diabetologia.

"Our findings suggest that early puberty could be a novel independent risk factor for type 2 diabetes in men," said senior author Dr. Jenny Kindblom of the Sahlgrenska Academy at University of Gothenburg.

"Given the apparent higher risk among boys who start puberty before the average age of 14 years, we estimate that 15% fewer men who were diagnosed during the study would have developed type 2 diabetes had they not started puberty early," Dr. Kindblom said.

The study included 30,697 men who had data for BMI at ages 8 and 20 years and height data to determine their age at PHV. Researchers identified 1,851 men out of this group who were diagnosed with type 2 diabetes in adulthood using data from the Swedish National Patient Register.

Among men who did develop type 2 diabetes, the median age at diagnosis was 57.2 years. Researchers looked at the impact of early puberty on early diabetes, before the median diagnosis age, as well as diagnosis at later ages.

They found that age at PHV was inversely associated with both early (HR 1.28 per year decrease in age at PHV) and late (HR 1.13) type 2 diabetes. After adjustment for childhood BMI, the associations between age at PHV and both early (HR 1.24) and late (HR 1.11) type 2 diabetes were similar.

But once researchers also accounted for BMI in early adulthood, the association was maintained but no longer statistically significant.

Early puberty was still significantly associated with early type 2 diabetes, also after adjustment for BMI at 20 years. In contrast, PHV after age 15 was associated with a 0.70 HR for early diabetes compared with men reaching PHV around age 14.

"Although the mechanisms for the link between early puberty and higher risk of type 2 diabetes are unclear, it is possible that starting puberty at an earlier age may lead to the accumulation of excess abdominal fat, which in turn increases cardiometabolic risk factors such as high blood pressure, diabetes and abnormal lipid levels," Dr. Kindblom said.

One limitation of the study is that researchers lacked data on BMI later in adulthood, or on family history of diabetes and smoking, which could impact diabetes risk.

It's also not clear that clinicians would necessarily ask men about their age at puberty, or that knowing this would impact how doctors treated patients, said Dr. Paul Kaplowitz, a professor emeritus of pediatrics at Children's National Hospital in Washington, D.C.

Whether they know about puberty timing or not, doctors would still advise patients to maintain a healthy weight to reduce their risk of developing type 2 diabetes, Dr. Kaplowitz, who wasn't involved in the study, said by email.

There is more evidence linking puberty timing to diabetes in girls than in boys, noted Dr. Elif Arioglu Oral of Michigan Medicine in Ann Arbor.

"Rapid weight gain through childhood can set off earlier puberty in girls, which increases the risk of earlier type 2 diabetes," Dr. Oral, who wasn't involved in the study, said by email. "For males the dots do not connect as sharply and easily, but overall, sticking with good nutrition, and following the accrual of weight and BMI points and if accelerated, being even more vigilant about increasing activity and nutrition are still advisable."

Good eating and exercise habits should start in childhood, said Dr. Mark DeBoer, a pediatric endocrinologist at the University of Virginia in Charlottesville.

"While there is almost nothing a parent can do to alter a child's timing of puberty, parents can help their child maintain a healthy BMI by encouraging them to eat healthy food choices and get frequent exercise," Dr. DeBoer, who wasn't involved in the study, said by email.

"When parents do note that their child has earlier puberty, it will be a good reminder for them to encourage lifelong healthy habits," Dr. DeBoer added. "When these habits are established in childhood the child is more likely to stick with them as an adult."

SOURCE: https://bit.ly/2QH0MDd Diabetologia, online March 23, 2020.