OBJECTIVE -To estimate the prevalence of the metabolic syndrome by age and sex in the RESEARCH DESIGN AND METHODS -We analyzed data from a cross-sectional survey conducted in 2001 containing a probability random sample of 1,419 Omani adults aged Ն20 years living in the city of Nizwa. The metabolic syndrome, defined by the ATP III, was defined as having three or more of the following abnormalities: waist circumference Ͼ102 cm in men and Ͼ88 cm in women, serum triglycerides Ն150 mg/dl (1.69 mmol/l), HDL cholesterol Ͻ40 mg/dl (1.04 mmol/l) in men and Ͻ50 mg/dl (1.29 mmol/l) in women, systolic blood pressure Ն130 mmHg and/or diastolic Ն85 mmHg or on treatment for hypertension, and fasting serum glucose Ն110 mg/dl (6.1 mmol/l) or on treatment for diabetes.RESULTS -The age-adjusted prevalence of the metabolic syndrome was 21.0%. The crude prevalence was slightly lower (17.0%). The age-adjusted prevalence was 19.5% among men and 23.0% among women (P ϭ 0.236). Low HDL cholesterol was the most common component (75.4%) of the metabolic syndrome among the study population followed by abdominal obesity (24.6%). Abdominal obesity was markedly higher in women (44.3%) than in men (4.7%).CONCLUSIONS -The prevalence of the metabolic syndrome in Oman is similar to that in developed countries. Future prevention and control strategies should not overlook the importance of noncommunicable disease risk factors in rapidly developing countries. Diabetes Care 26:1781-1785, 2003P eople with abnormal glucose metabolism, hypertension, obesity, and dyslipidemia constitute a major challenge facing health systems in developed and developing countries. Such people are at substantially increased risk of developing diabetes and cardiovascular diseases (CVDs), including coronary artery, cerebrovasular, and peripheral vascular diseases necessitating long-term care (1,2).Several studies have illustrated a high prevalence of diabetes, impaired glucose tolerance, obesity, and hypertension among Arab populations of the Middle East, including Omanis (3-10). However, all of these studies focused on estimating the population distribution of major risk factors for CVDs, and only one (11) RESEARCH DESIGN AND METHODS Study populationAs part of the initiative to obtain baseline data on CVD risk factors before the implementation of a community-based healthy lifestyle intervention project, a crosssectional survey was conducted between April and June 2001 in the city of Nizwa (capital of the main Interior Province of Oman with 66,000 inhabitants and 180 km away from the national capital Muscat) (Fig. 1). The target group was all Omanis aged Ն20 years who resided in this city for at least 6 months before the date of the survey. The sample size, 1,000 men and women, was calculated for gender-specific analyses based on the estimate of the national prevalence of diabetes (10%), a nonresponse rate of 20%, and an error margin of 20% on each side of the 95% confidence intervals for any point estimate (Epinfo version 6; CDC, Atlanta, GA). Two-stage cluster sampling wa...