Aims: To determine the obesity indices, specifically waist circumference (WC), that identified ≥2 other metabolic syndrome (MS) components (2009 criteria) in 25- to 74-year-old Africans in Cape Town.
Methods: Data were collected from a cross-sectional sample by administered questionnaires, clinical measurements and biochemical analyses. The obesity cut points were estimated by the Youden Index. Logistic regression analyses determined whether obesity cut points identifying ≥2 MS components occurred at true inflection points.
Results: Among the 1099 participants, the calculated cut points and 95% confidence intervals (CI) were: men, WC 83.9 cm (81.6-86.2), waist-to-hip ratio (WHR) 0.89 (0.87-0.90), waist-to-height ratio (WHtR) 0.50 (0.48-0.52) and body mass index (BMI) 24.1 kg/m(2) (22.0-26.1); women, WC 94.0 cm (92.6-95.3), WHR 0.85 (0.83-0.87), WHtR 0.59 (0.57-0.60) and BMI 32.1 kg/m(2) (29.7-34.6). Raised WC was significantly associated with ≥2 MS components in men: WC 84.0-93.9 cm (odds ratio (OR): 3.19, 95% confidence interval (CI): 1.73-5.85) and WC ≥94.0 cm (OR: 8.50, 95% CI: 4.44-16.25) compared with WC <84.0 cm, and in women: WC 80.0-93.9 cm (OR: 2.93, 95% CI: 1.32-6.54) and WC ≥94.0 cm (OR: 5.33, 95% CI: 2.40-11.85) compared with WC <80.0 cm. In the logistic model with BMI for women, obesity (OR: 3.60, 95% CI: 1.82-7.10) but not overweight (P = 0.063) was significantly associated with ≥2 MS components.
Conclusions: Obesity cut points for Africans should be re-evaluated and adjusted accordingly.
Keywords: BMI; Black; South Africa; obesity; obesity threshold; urban; waist circumference.
© The Author 2015. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.