Estimating the effects of body mass index and central obesity on stroke in diabetics and non-diabetics using targeted maximum likelihood estimation: Atherosclerosis Risk in Communities study

Hossein Mozafar Saadati; Yadollah Mehrabi; Siamak Sabour; Mohammad Ali Mansournia; Seyed Saeed Hashemi Nazari

doi:10.1002/osp4.447

Estimating the effects of body mass index and central obesity on stroke in diabetics and non-diabetics using targeted maximum likelihood estimation: Atherosclerosis Risk in Communities study

Obes Sci Pract. 2020 Aug 18;6(6):628-637. doi: 10.1002/osp4.447. eCollection 2020 Dec.

Authors

Hossein Mozafar Saadati¹, Yadollah Mehrabi¹, Siamak Sabour¹, Mohammad Ali Mansournia², Seyed Saeed Hashemi Nazari³

Affiliations

¹ Department of Epidemiology, School of Public Health and safety Shahid Beheshti University of Medical Sciences Tehran Iran.
² Department of Epidemiology and Biostatistics, School of Public Health Tehran University of Medical Sciences Tehran Iran.
³ Prevention of Cardiovascular Disease Research Center, Department of Epidemiology, School of Public Health and Safety Shahid Beheshti University of Medical Sciences Tehran Iran.

Abstract

Objectives: The association of body mass index (BMI) with the risk of cardiovascular disease among diabetic patients is controversial. This study compared the effects of BMI and central obesity on stroke in diabetics and non-diabetics using targeted maximum likelihood estimation.

Materials and methods: This analysis included 12 725 adults aged 45-75 years, after excluding prevalence cases and participants with missing data, from the Atherosclerosis Risk in Communities study. Obesity was defined with BMI, waist circumference, waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), body shape index (BSI) and body roundness index (BRI), which categorized all participants as obese and non-obese. Generalized linear models and TMLE (with the tmle package) were used to estimate risk ratio (RR).

Results: During 27 years of follow-up, 1078 (8.47%) cases of stroke occurred. After adjustment for demographic, behavioural, biologic and central obesity variables, the effect of BMI decreased in both diabetics and non-diabetics. The effect of BMI in diabetics was more attenuated, in full model, (RR: 1.04 [0.90, 1.20]) rather than non-diabetics (RR: 1.11 [1.00, 1.24]). This attenuation was more related to biologic variables in non-diabetics and central obesity in diabetics. With respect to central obesity, BSI (RR [95% CI]: 1.15 [0.96, 1.38]) and WHR (RR [95% CI]: 1.15 [0.87, 1.52]) had strongest and marginally significant effects for diabetics and BSI (RR [95% CI]: 1.10 [1.02, 1.20]) for non-diabetics.

Conclusions: Among diabetics, BSI and WHR indices were associated with a higher incidence of stroke. Future studies should consider how central obesity affects higher incidence of stroke among diabetics stratified by sex and age groups.

Keywords: diabetes; obesity; stroke.