Metabolic syndrome and coronary heart disease in South Asians, African-Caribbeans and white Europeans: a UK population-based cross-sectional study.

AIMS/HYPOTHESIS: The aim of this study was to study differences in the prevalence of the metabolic syndrome and its associations with prevalent CHD according to ethnicity and sex. METHODS: We performed a combined analysis of two population-based cross-sectional studies conducted between 1988 and 1991 that followed identical protocols. Participants (aged 40-69 years) comprised 2,346 Europeans (76% male), 1,711 South Asians (83% male) and 803 African-Caribbeans (57% male) resident in west London. Fasting blood, overnight urine collection, clinical and anthropometric measurements were performed. Clinical history or major ECG changes defined prevalent CHD. The metabolic syndrome was defined according to the criteria recommended by the World Health Organization (WHO) and the National Cholesterol Education Programme (NCEP). RESULTS: The prevalence of the metabolic syndrome was highest in South Asians (WHO, men 46%, women 31%; NCEP, men 29%, women 32%) and lowest in European women (WHO, 9%; NCEP, 14%). The prevalence of CHD was 10% in South Asian men, 9% in European men, 5-6% in African-Caribbeans and European women, and 2% in South Asian women. The metabolic syndrome was associated with prevalent CHD in European men [NCEP, odds ratio (OR)=1.6, 95% CI 1.2-2.4; WHO, OR=1.7, 95% CI 1.2-2.5] and South Asian men (NCEP, OR=2.1, 95% CI 1.5-3.1; WHO, OR=1.6, 95% CI 1.1-2.3). Associations with CHD were weaker in African-Caribbeans and were inconsistent among European women. CONCLUSIONS/INTERPRETATION: The current definitions of the metabolic syndrome give an inconsistent picture of cardiovascular disease risk when applied to different ethnic groups within the UK. Prospective studies are needed to validate workable ethnic-specific definitions.