Public Health Nutrition

Research Paper

Body mass index, waist circumference and waist-to-hip ratio cut-off points for categorisation of obesity among Omani Arabs

Jawad A Al-Lawatia1 c1 and Pekka Jousilahtia2a3

a1 Department of Non-communicable Diseases Surveillance & Control, PO Box 393, Muscat 113, Ministry of Health, Oman

a2 Department of Health Promotion and Chronic Disease Prevention, National Public Health Institute, Helsinki, Finland

a3 School of Public Health, University of Tampere, Tampere, Finland

Abstract

Background There are no data on optimal cut-off points to classify obesity among Omani Arabs. The existing cut-off points were obtained from studies of European populations.

Objective To determine gender-specific optimal cut-off points for body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) associated with elevated prevalent cardiovascular disease (CVD) risk among Omani Arabs.

Design A community-based cross-sectional study.

Setting The survey was conducted in the city of Nizwa in Oman in 2001.

Subjects and methods The study contained a probabilistic random sample of 1421 adults aged ≥20 years. Prevalent CVD risk was defined as the presence of at least two of the following three risk factors: hyperglycaemia, hypertension and dyslipidaemia. Logistic regression and receiver-operating characteristic (ROC) curve analyses were used to determine optimal cut-off points for BMI, WC and WHR in relation to the area under the curve (AUC), sensitivity and specificity.

Results Over 87% of Omanis had at least one CVD risk factor (38% had hyperglycaemia, 19% hypertension and 34.5% had high total cholesterol). All three indices including BMI (AUC = 0.766), WC (AUC = 0.772) and WHR (AUC = 0.767) predicted prevalent CVD risk factors equally well. The optimal cut-off points for men and women respectively were 23.2 and 26.8 kg m−2 for BMI, 80.0 and 84.5 cm for WC, and 0.91 and 0.91 for WHR.

Conclusions To identify Omani subjects of Arab ethnicity at high risk of CVD, cut-off points lower than currently recommended for BMI, WC and WHR are needed for men while higher cut-off points are suggested for women.

(Received December 12 2006)

(Accepted February 21 2007)

Correspondence

c1 Corresponding author: Email jallawat@yahoo.com

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