Data from: Association of body mass index and age with incident diabetes in Chinese adults: a population-based cohort study

Objective. Type 2 diabetes mellitus is increasing in young adults, and
greater adiposity is considered a major risk factor. However, whether
there is an association between obesity and diabetes and how this might be
impacted by age is not clear. Therefore, we investigated the association
between body mass index (BMI) and diabetes across a wide range of age
groups (20-30, 30-40, 40-50, 50-60, 60-70, ≥70 years old). Design. We
performed a retrospective cohort study using healthy screening program
data. Setting. A total of 211,833 adult Chinese persons >
20-years-old across 32 sites and 11 cities in China (Shanghai, Beijing,
Nanjing, Suzhou, Shenzhen, Changzhou, Chengdu, Guangzhou, Hefei, Wuhan,
Nantong) were selected for the study; these persons were free of diabetes
at baseline. Primary and secondary outcome measures. Fasting plasma
glucose levels were measured and information regarding the history of
diabetes was collected at each visit. Diabetes was diagnosed as fasting
plasma glucose ≥ 7.00 mmol/L and/or self-reported diabetes. Patients were
censored at the date of diagnosis or the final visit, whichever came
first. Results. With a median follow-up of 3.1 years, 4,174 of the 211,833
participants developed diabetes, with an age-adjusted incidence rate of
7.35 per 1,000 persons. The risk of incident diabetes increased
proportionally with increasing baseline BMI values, with a 23% increased
risk of incident diabetes with each kg/m2 increase in BMI (95%CI: 1.22,
1.24). Across all age groups, there was a linear association between BMI
and the risk of incident diabetes, although there was a stronger
association between BMI and incident diabetes in the younger age groups
(age × BMI interaction, P < 0.0001). Conclusions. An increased BMI
is also independently associated with a higher risk of developing diabetes
in young adults and the effects of BMI on incident diabetes were
accentuated in younger adults.