To estimate the prevalence of the metabolic syndrome (MS) in a population of patients with overweight and obesity of the A Coruña and Granada health areas, using the definitions of the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults (ATP III) and of the International Diabetes Federation (IDF).

During a period extending from 1996 to 2003, only those patients attending endocrinology outpatient clinics for whom all the anthropometric and biochemical parameters used to define the MS, both according to the ATP IIII and the IDF, were available were selected. The final study sample consisted of 285 patients, 198 females (69.5%) and 87 males (30.5%).

The prevalence of the MS was 29.8% when the ATP III definition was applied, and 41.1% according to the IDF criteria. Prevalence by sex was 32.2% in men and 28.8% in women according to the ATP III, and 42.5% and 40.4%, respectively, according to the IDF.

In a patient population with overweight or obesity, the prevalence of the MS is higher when the IDF criteria, instead of the ATP III criteria, are used. These findings may have significant implications when it comes to addressing early diagnosis of cardiovascular disease and diabetes mellitus in these patients, in order to perform therapeutic measures at the initial stages and thereby reduce metabolic and cardiovascular complications.