Ethnicity-specific obesity cut-points in the development of Type 2 diabetes - a prospective study including three ethnic groups in the United Kingdom

Diabet Med. 2015 Feb;32(2):226-34. doi: 10.1111/dme.12576. Epub 2014 Oct 1.

Abstract

Aims: Conventional definitions of obesity, e.g. body mass index (BMI) ≥ 30 kg/m² or waist circumference cut-points of 102 cm (men) and 88 cm (women), may underestimate metabolic risk in non-Europeans. We prospectively identified equivalent ethnicity-specific obesity cut-points for the estimation of diabetes risk in British South Asians, African-Caribbeans and Europeans.

Methods: We studied a population-based cohort from London, UK (1356 Europeans, 842 South Asians, 335 African-Caribbeans) who were aged 40-69 years at baseline (1988-1991), when they underwent anthropometry, fasting and post-load (75 g oral glucose tolerance test) blood tests. Incident Type 2 diabetes was identified from primary care records, participant recall and/or follow-up biochemistry. Ethnicity-specific obesity cut-points in association with diabetes incidence were estimated using negative binomial regression.

Results: Diabetes incidence rates (per 1000 person years) at a median follow-up of 19 years were 20.8 (95% CI: 18.4, 23.6) and 12.0 (8.3, 17.2) in South Asian men and women, 16.5 (12.7, 21.4) and 17.5 (13.0, 23.7) in African-Caribbean men and women, and 7.4 (6.3, 8.7), and 7.2 (5.3, 9.8) in European men and women. For incidence rates equivalent to those at a BMI of 30 kg/m² in European men and women, age- and sex-adjusted cut-points were: South Asians, 25.2 (23.4, 26.6) kg/m²; and African-Caribbeans, 27.2 (25.2, 28.6) kg/m². For South Asian and African-Caribbean men, respectively, waist circumference cut-points of 90.4 (85.0, 94.5) and 90.6 (85.0, 94.5) cm were equivalent to a value of 102 cm in European men. Waist circumference cut-points of 84.0 (74.0, 90.0) cm in South Asian women and 81.2 (71.4, 87.4) cm in African-Caribbean women were equivalent to a value of 88 cm in European women.

Conclusions: In prospective analyses, British South Asians and African-Caribbeans had equivalent diabetes incidence rates at substantially lower obesity levels than the conventional European cut-points.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Asians
  • Blacks
  • Body Mass Index
  • Caribbean Region / ethnology
  • Cohort Studies
  • Diabetes Mellitus, Type 2 / diagnosis
  • Diabetes Mellitus, Type 2 / epidemiology
  • Diabetes Mellitus, Type 2 / ethnology
  • Diabetes Mellitus, Type 2 / etiology*
  • Diagnosis, Differential
  • Female
  • Humans
  • Incidence
  • Insulin Resistance* / ethnology
  • London / epidemiology
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Obesity / diagnosis
  • Obesity / ethnology
  • Obesity / physiopathology*
  • Overweight / diagnosis
  • Overweight / ethnology
  • Overweight / physiopathology*
  • Prospective Studies
  • Risk Factors
  • Urban Health* / ethnology
  • Whites