Abstract
BackgroundPrevious studies reported that aged population with overweight had a lower mortality after cardiovascular diseases attack, indicating being thinner might not be better. However, the debate is ongoing what is optimal range of body mass index (BMI) for aged population. We aimed to evaluate the association between BMI and incident diabetes mellitus (DM) in Chinese elderly people.Methods6,489 Chinese elderly people (3,828 men and 2,661 women) with medium age of 69 years (interquartile range: 67-74 years) were included in this cohort study. BMI was measured at baseline (2014). All the participants were further classified into eight groups based on baseline BMI with 2.0 kg/m2 interval: ≤17.9 kg/m2, 18.0-19.9 kg/m2, 20.0-21.9 kg/m2, 22.0-23.9 kg/m2, 24.0-25.9 kg/m2, 26.0-27.9 kg/m2, 28.0-29.9 kg/m2, and ≥30.0 kg/m2. Fasting blood glucose (FBG) and glycated hemoglobin A1c (HbA1c) were annually measured during follow-up (2014-2019). DM was confirmed if either FBG ≥7.0 mmol/L or HbA1c ≥6.5%. We used the Cox proportional hazards regression model to evaluate the association between BMI and incident DM.ResultsComparing individuals with a BMI range of 20.0~21.9 kg/m2 (reference), the hazards ratio for incident DM was 2.07 (95% CI: 1.33, 3.22), 2.07 (95% CI: 1.33, 3.23), 2.18 (95% CI: 1.37, 3.47), 2.68 (95% CI: 1.61, 4.46), and 2.26 (95% CI: 1.17, 4.37) for the group with a BMI range of 22.0-23.9 kg/m2, 24.0-25.9 kg/m2, 26.0-27.9 kg/m2, 28.0-29.9 kg/m2, and ≥30.0 kg/m2 after adjusting baseline age, sex, blood pressure, lipid profiles, and eGFR. Each unit increase of BMI (=1.0 kg/m2) was associated with a high risk of 9% (HR=1.09, 95% CI: 1.05, 1.14, P for trend<0.001) after adjusting for above-mentioned confounders.ConclusionsHigh BMI was associated with high risk of developing DM in Chinese aged population. To lower the incidence of DM, it is better to be thinner than heavier.