Ethnicity-specific association of BMI levels at diagnosis of type 2 diabetes with cardiovascular disease and all-cause mortality risk.

AIM: To evaluate the risk of CVD and all-cause mortality at different BMI levels in conjunction with weight change prior to diagnosis of T2DM in a multi-ethnic population.

METHODS: Longitudinal study of 51,455 patients with T2DM and without a history of comorbid diseases at diagnosis. Weight changes prior to diagnosis of T2DM were evaluated, and the risk of CVD and all-cause mortality at different BMI levels among three ethnic groups estimated using treatment effects model.

RESULTS: White Europeans (WE), African-Caribbeans (AC), and South Asians (SA) were mean 52, 49, and 47 years with a mean BMI of 33.0, 32.0, and 30.0 kg/m2 at diagnosis, respectively. Among WE, normal weight patients developed CVD significantly earlier by 0.5 years (95% CI 0.1, 0.9 years; p = 0.018) compared to obese patients. Furthermore, those with normal body weight at diagnosis were significantly more likely to die earlier by 0.6 years (95% CI 0.03, 1.2 years; p = 0.037) among WE and by 2.5 years (95% CI 0.3, 4.6 years; p = 0.023) among SA compared to their respective obese patients. However, BMI at diagnosis was not associated with increased risk of CVD and death among AC.

CONCLUSIONS: This study suggests a paradoxical association of BMI with cardiovascular and mortality risks in different ethnic groups, which may partially be driven by different cardiovascular and glycaemic risk profiles at diagnosis.