Predictive value of abdominal obesity cut-off points for hypertension in Blacks from West African and Caribbean island nations

BACKGROUND: Waist circumferences (WC) ≥ 94 cm for men and ≥ 80 cm for women (action level I) and ≥ 102 cm for men and ≥ 88 cm for women (action level II) have been suggested as limits for health promotion purposes to alert the general public to the need for weight loss. In this analysis we examined the ability of the above cut-off points to correctly identify subjects with or without hypertension in Nigeria, Cameroon, Jamaica, St Lucia and Barbados. We also determined population- and gender-specific abdominal adiposity cut-off points for epidemiological identification of risk of hypertension. METHODS: Waist measurement was made at the narrowest part of the torso as seen from the front or at midpoint between the bottom of the rib cage and 2 cm above the top of the iliac crest. Sensitivity and specificity of the established WC cut-off points for hypertension were compared across sites. With receiver operating characteristics (ROC), population- and gender-specific cut-off points associated with risk of hypertension were determined over the entire range of WC values. RESULTS: Predictive abilities of the established WC cut-off points for hypertension were poor compared to the specific cut-off points estimated for each population. Different values of WC were associated with increased risk of hypertension in these populations. In men, WC cut-off points of 76, 81, 80, 83 and 87 cm provided the highest sensitivity for identifying hypertensives in Nigeria, Cameroon, Jamaica, St Lucia and Barbados, respectively. The analogous cut-off points in women were 72, 82, 85, 86 and 88 cm. CONCLUSIONS: The waist cut-off points from this study represent values for epidemiological identification of risk of hypertension. For the purpose of health promotion, the decision on what cut-off points to use must be made by considering other additional factors including overall impact on health due to intervention (e.g. weight reduction) and potential burden on health services if a low cut-off point is employed. There is a need to develop abdominal adiposity cut-off points associated with increased risks for cardiovascular diseases in different societies, especially for those populations where the distribution of obesity and associated risk factors tends to be very different from those of the technologically advanced nations.