[Population study of premenstrual syndrome].

OBJECTIVE To study the prevalence of premenstrual syndrome and the factors associated with this, by comparing the obtained frequency with the self-reported frequency. METHODS This was a cross-sectional population-based study, involving 1,395 women aged 15 to 49 years old in a medium-sized municipality in Southern Brazil, carried out in 2003. Questionnaires were applied to measure the prevalence of premenstrual syndrome by means of a score based on five premenstrual symptoms that interfered with family life or led to absence from work or school. Associations with socioeconomic, demographic and behavioral variables were investigated. Self-reported syndrome was investigated with regard to its sensitivity and specificity, taking the score as the gold standard. The statistical analyses performed were Pearson chi2, Mantel-Haenszel and Poisson regression, with Kappa coefficients to verify the concordance of the responses. RESULTS The obtained prevalence was 25.2% (95% CI: 22.5-27.9) and the self-reported prevalence was 60.3% (95% CI: 57.4-63.3). The principal premenstrual symptoms found were: irritability, abdominal discomfort, nervousness, headache, fatigue and breast pain; all of these showed prevalence of over 50%. Higher risk was presented by women of higher socioeconomic level, better schooling level, aged under 30 years and with white skin color. Psychotropic drug users and women who were not using any hormonal contraceptive presented higher prevalence of the syndrome. The sensitivity of the test was 94%, specificity 51% and accuracy 62%. CONCLUSIONS A high prevalence of premenstrual syndrome was found. Even though the women's perception of the syndrome was higher than the result measured by the symptom score, one quarter of the women presented this health problem.