Premenstrual symptoms and syndrome according to age at menarche in a 1982 birth cohort in southern Brazil.

Premenstrual symptoms and syndrome were studied in young women who have been followed since birth. Data were collected on the intensity of four symptoms: irritability, anxiety or stress, depressed mood, and affective lability. Premenstrual syndrome was defined according to intensity of symptoms. Association between age at menarche and premenstrual symptoms and syndrome were investigated through Poisson regression. Adjusted analysis was conducted, controlling for possible confounding factors. The symptoms most frequently reported by the women from the 1982 Pelotas, Rio Grande do Sul, Brazil, birth cohort who were interviewed in 2004-2005 were: irritability (52.3%) and anxiety (40.2%). The prevalence rates for moderate and severe premenstrual syndrome were 13.4% and 5.8%, respectively. Mean age at menarche was 12.4 (+/-1.5) years. Prevalence rates for symptoms and premenstrual syndrome were higher in women whose age at menarche was less than 11 years, but this difference was not statistically significant. Information on symptoms and premenstrual syndrome is scarce in other studies.