Relationship between body mass index and risk of type 2 diabetes mellitus in the elderly

Liu Hongzhou; Du Yangfan; Wang Linlin; Dong Song; Shi Ying; Liu Jing; Yang Hua; Yan Shuangtong; Fu Xiaomin

doi:10.3969/j.issn.1674-3245.2025.04.023

Abstract：Objective To analyze the interaction of age and sex in the relationship between body mass index(BMI)and the risk of type 2 diabetes mellitus(T2DM)in the elderly population.Methods This retrospective cohort study was based on a database and included 16,903 elderly individuals aged 60 years or older without T2DM at baseline,with a maximum follow-up of seven years.BMI was first analyzed as both a continuous and categorical variable in relation to the risk of T2DM,and the multiplicative and additive interactions of age and sex were examined.Finally,Mendelian randomization(MR)analysis was used to assess the causal relationship between BMI and the risk of T2DM.Results When BMI was treated as a continuous variable,after adjusting for confounders,the hazard ratio(HR)for T2DM increased with BMI(HR=1.257,95％CI:1.047～1.511),with the rate of increase being initially rapid and then slowing down.The inflection point of this change was identified at BMI=27.63 kg/m2.When BMI was treated as a categorical variable,a higher BMI category was associated with an increased risk of T2DM(p for trend＜0.001).Stratifying the population by age at a cutoff of 75 years,neither age nor sex showed significant multiplicative or additive interactions with BMI in relation to T2DM risk.MR analysis indicated that an increase in BMI was associated with a higher risk of T2DM,with an odds ratio(OR)of 1.368(95％CI:1.212～1.523).Conclusion In the elderly population,an increase in BMI is associated with a higher risk of T2DM,and neither sex nor age exhibits significant additive or multiplicative interactions in this relationship.