Objectives To estimate the prevalence of the metabolic syndrome (MS) and its components among young adults born in 1978–9 in Ribeirão Preto, SP, and to evaluate to what extent factors indicative of intrauterine malnutrition and excess weight during childhood are associated with MS.

Methods 1070 subjects born in the Ribeirão Preto cohort were evaluated. Information was collected at birth (newborn sex and adequacy of birth weight for gestational age, classified as adequate for gestational age, small for gestational age and large for gestational age), at school age (excess weight or not) and at 23/25 years (occupation, schooling, smoking habit and family history of cardiovascular diseases). MS was defined according to the consensus of the International Diabetes Federation. Stepwise multiple logistic regression analysis was applied, with MS being the dependent variable.

Results The prevalence of MS was 9.5% (14.2% among men and 5.3% among women). Among the components of the syndrome, the following features were detected: increased waist circumference in 26.4%, hypertension in 22.2%, low high-density lipoprotein in 39.9%, hyperglycaemia in 2.5% and hypertriglyceridaemia in 13.5%. Boys (odds ratio (OR) 3.24) with excess weight at school age (OR 3.32), smokers (OR 3.46) and with a history of parental cardiovascular diseases (OR 1.63) had a higher risk of MS.

Conclusions The prevalence of MS was elevated considering that this is a young population. Weight gain at school age was found to be associated with the risk of MS, in contrast to birth conditions.