medwireNews: Children who are overweight only have an increased risk for type 2 diabetes in adulthood if they remain overweight beyond the age of 13 years, according to the results of a large Danish study.
As reported in The New England Journal of Medicine, Lise Bjerregaard (Bispebjerg and Frederiksberg Hospital, Copenhagen) and co-investigators used a national health registry to analyze the association between patterns of BMI in early life and the risk for type 2 diabetes after 30 years of age among 62,565 men, 10.7% of whom were diagnosed with the disease over 1,969,165 person–years of follow-up.
The 3373 participants who were overweight or obese at 7 years of age (BMI ≥17.38 kg/m2), as well as the 3418 and 5108 men who were overweight or obese at 13 years (BMI ≥21.82 kg/m2) and between 17 and 26 years (BMI ≥25.00 kg/m2), respectively, had a significantly increased risk for being diagnosed with diabetes at the age of 30–60 years compared with the 54,529 men who maintained a healthy bodyweight at all ages.
However, men who had been overweight aged 7 years but who had a healthy bodyweight by the age of 13 years, which they maintained in early adulthood, had a similar risk for being diagnosed with diabetes between 30 and 60 years of age as those who had never been overweight.
Men who were overweight at the age of 7 or 13 years but not during early adulthood had a significant 47% higher risk for type 2 diabetes than those who maintained a healthy bodyweight. Nevertheless, their risk was lower than that for men who were persistently overweight, who were more than four times as likely as those who were never overweight to develop type 2 diabetes.
“Childhood overweight at 7 years of age was associated with increased risks of adult type 2 diabetes only if it continued until puberty or later ages,” summarize the researchers.
They highlight that being “overweight during puberty appears to be a particularly important factor involved in increasing the risk of type 2 diabetes in middle and late adulthood,” indicating that “normalization of BMI before these ages may reduce this risk.”
These findings remained consistent in subgroup analyses based on intelligence test scores and level of education. The researchers also observed similar patterns when analyzing the relationship between BMI in early life and the likelihood of being diagnosed with type 2 diabetes after 60 years of age, but note that the risks were higher for diagnosis before, rather than after, 60 years.
“This difference is probably attributable to a decrease in the correlation between child BMI and adult BMI as adult age increases,” they say.
When the team analyzed the relationship between BMI and diabetes risk by percentile, they found that of the 501 men who were categorized as obese (BMI in the ≥95th percentile) at the age of 7 years, the 31.1% who reduced their BMI to the overweight category (BMI in 85th to 94th percentiles) by early adulthood halved their risk for type 2 diabetes compared with the 33.1% who remained obese.
And the researchers emphasize that participants who were obese in early adulthood had a “very high risk” for type 2 diabetes, regardless of their BMI at the age of 7 years.
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