Prevalence and determinants of obesity in an urban sample of Portuguese adults

Abstract

Objective. To evaluate the prevalence and the determinants of obesity, and the associated cardiovascular risk factors in a random sample of non-institutionalised adults. Design. Cross-sectional study. Subjects. A random sample of 1436 habitants of Porto (873 women and 563 men) aged 18–90 years. Measurements. All participants answered a structured questionnaire comprising information on social, demographic, behavioural and clinical aspects. Anthropometric measures, blood pressure and fasting blood samples were obtained. Diet was assessed using a semi-quantitative food-frequency questionnaire, and physical activity was evaluated using a questionnaire exploring all professional, domestic and leisure-time activities. When the body mass index was ≥30 kg/m 2, the subject was considered as ‘obese’. Proportions were age adjusted for the European population. Odds ratios and 95% confidence intervals were computed using unconditional logistic regression. Results. The prevalence of obesity was significantly higher in women (26.1%) than men (13.9%). Regardless of gender, obesity increased with age, decreased with education, and was more frequent in married blue-collar workers and unemployed subjects. Smoking was more prevalent in subjects of normal weight, and a higher proportion of those reporting no regular exercise were obese. In men, obesity prevalence increased with increasing quartiles of energy intake, but no such changes were found in women. Compared with subjects of normal weight, obese men showed a significantly higher prevalence of hypertension (53.3 vs 26.1%) and hypertriglyceridaemia (23.4 vs 9.0%). Also, hypertension (43.7 vs 30.7%), diabetes (7.6 vs 2.7%), hypertriglyceridaemia (27.1 vs 5.0%), and abnormal low-density lipoprotein (30.4 vs 21.4%) and high-density lipoprotein cholesterol concentration (15.0 vs 5.3%) were more frequent in obese women. Conclusion. Obesity is a major public health issue in urban Portuguese populations, and obese individuals have many features of metabolic syndrome. Education and relative deprivation are modifiable factors that are significantly associated with obesity. However, no clear-cut relationship was found between physical activity and energy intake.