Secular trend in age at menarche in women in Portugal born between 1920 and 1992: Results from three population-based studies.

OBJECTIVES: Worldwide data on age at menarche suggest a gradually earlier maturation, which is stabilizing in some societies. The interplay between socioeconomic, behavioral, and environmental factors generates uncertainty about the current status and future trend of age at menarche in most societies. Therefore, we aimed to describe trends in age at menarche during the 20th century in Portugal. METHODS: A sample of 11 274 women born between 1920 and 1992 in northern Portugal, recruited to participate in three population-based cohorts (EPIPorto, EPITeen, and Generation XXI) was evaluated. Age at menarche across birth year categories was compared using ANOVA and the rate of change over time using linear regression. RESULTS: Age at menarche decreased with birth year (-31.1 days per 5 years; ß = -.017, P < .001), women born before 1930 having a significantly higher age at menarche than those who were born after 1990 (mean (SD) = 13.1 (1.83) vs 12.0 (1.25), P < .001). CONCLUSIONS: The decrease in age at menarche in northern Portugal suggests that a plateau is yet to be reached. Attention to time trends in age at menarche is relevant for health promotion since there is a possible relationship between pubertal timing and the later development of the metabolic syndrome.

The association between school holidays and unintentional fatal drowning among children and adolescents aged 5-17 years.

AIM: Children aged 5-17 years in Australia have one of the lowest unintentional fatal drowning rates. One possible explanation is the protective effect of formal schooling, reducing leisure time for exposure to water hazards. We examine differences in frequency and circumstances of drowning deaths in this age group between school holidays and school days in Australia. METHODS: A total population survey (2005-2014) of unintentional fatal drownings was extracted from the (Australian) Royal Life Saving National Fatal Drowning Database. Date of drowning incident and state of residence were used to determine if the drowning occurred during school days or school holidays (including public holidays). RESULTS: A total of 188 5-17 year-olds drowned during the study period. We found a statistically significant difference between drowning incidence during school holidays and school days, with relative risk (RR) of drowning on a holiday 2.40 times higher (confidence interval (CI): 1.82-3.18) than on a school day. This risk was similar for males (RR = 2.41; CI: 1.75-3.33) and females (RR = 2.38; CI: 1.33-4.27) but differs between children 5-9 years (RR = 3.05; CI: 1.98-4.72) and adolescents 10-17 years of age (RR = 2.02; CI: 1.38-2.93). CONCLUSIONS: Drowning rates among 5-17 year-olds are more than twice as high during holidays than on school days. Impact of school holidays was the strongest among younger children, visitors to the drowning location and in pools and inland waterways. Results were robust to alternative specifications excluding weekends and treating them as holidays. Prevention strategies may include counselling parents and care providers of the increased risk ahead of school holidays, education on drowning risk in the school curriculum and extra holidays for parents and care givers.