Defining Obesity Cut-Off Points for Migrant South Asians

BackgroundBody mass index (BMI) and waist circumference (WC) are used to define cardiovascular and type 2 diabetes risk. We aimed to derive appropriate BMI and WC obesity cut-off points in a migrant South Asian population. Methods4688 White Europeans and 1333 South Asians resident in the UK aged 40–75 years inclusive were screened for type 2 diabetes. Principal components analysis was used to derive a glycaemia, lipid, and a blood pressure factor. Regression models for each factor, adjusted for age and stratified by sex, were used to identify BMI and WC cut-off points in South Asians that correspond to those defined for White Europeans. FindingsFor South Asian males, derived BMI obesity cut-off points equivalent to 30.0 kg/m2 in White Europeans were 22.6 kg/m2 (95% Confidence Interval (95% CI) 20.7 kg/m2 to 24.5 kg/m2) for the glycaemia factor, 26.0 kg/m2 (95% CI 24.7 kg/m2 to 27.3 kg/m2) for the lipid factor, and 28.4 kg/m2 (95% CI 26.5 kg/m2 to 30.4 kg/m2) for the blood pressure factor. For WC, derived cut-off points for South Asian males equivalent to 102 cm in White Europeans were 83.8 cm (95% CI 79.3 cm to 88.2 cm) for the glycaemia factor, 91.4 cm (95% CI 86.9 cm to 95.8 cm) for the lipid factor, and 99.3 cm (95% CI 93.3 cm to 105.2 cm) for the blood pressure factor. Lower ethnicity cut-off points were seen for females for both BMI and WC. ConclusionsSubstantially lower obesity cut-off points are needed in South Asians to detect an equivalent level of dysglycemia and dyslipidemia as observed in White Europeans. South Asian ethnicity could be considered as a similar level of risk as obesity (in White Europeans) for the development of type 2 diabetes.背景：体重指数（Body mass index, BMI）与腰围（waist circumference, WC）被用于界定心血管疾病及2型糖尿病风险。本研究旨在为居住在英国的南亚移民人群确定适宜的BMI与腰围肥胖界值。 方法：本研究对4688名居住于英国、年龄介于40至75岁（含两端）的白种欧洲人，以及1333名南亚裔人群开展2型糖尿病筛查。采用主成分分析（Principal Components Analysis）提取血糖、血脂与血压因子。以校正年龄、按性别分层的各因子回归模型，确定与白种欧洲人群既定肥胖界值相对应的南亚裔人群BMI与腰围界值。 结果：对于南亚男性，与白种欧洲人群中30.0 kg/m²对应的BMI肥胖界值分别为：血糖因子界值22.6 kg/m²（95%置信区间（95% Confidence Interval, 95% CI）20.7~24.5 kg/m²）、血脂因子界值26.0 kg/m²（95% CI 24.7~27.3 kg/m²）、血压因子界值28.4 kg/m²（95% CI 26.5~30.4 kg/m²）。就腰围而言，与白种欧洲人群中102 cm对应的界值分别为：血糖因子界值83.8 cm（95% CI 79.3~88.2 cm）、血脂因子界值91.4 cm（95% CI 86.9~95.8 cm）、血压因子界值99.3 cm（95% CI 93.3~105.2 cm）。南亚女性的BMI与腰围界值均低于男性。 结论：南亚人群需要显著更低的肥胖界值，方可检出与白种欧洲人群相当的糖代谢异常与血脂异常水平。南亚裔种族因素可被视为与白种欧洲人群肥胖（相关风险）等效的2型糖尿病发病风险因素。