Temporal trends in age at menarche and age at menopause: a population study of 312 656 women in Norway.

STUDY QUESTION: Have mean age at menarche or mean age at natural menopause changed from the 1939 birth cohort to the 1964 birth cohort? SUMMARY ANSWER: We estimated a minor decrease in mean age at menarche and an increase by nearly 3 years in mean age at natural menopause. WHAT IS KNOWN ALREADY: In the Western world, age at menarche decreased across birth cohorts from the early 1800s until the 1950s. Whether mean age at menarche has continued to decrease in birth cohorts after the 1950s remains uncertain. It is also uncertain whether mean age at natural menopause has changed across birth cohorts. STUDY DESIGN, SIZE, DURATION: We performed a retrospective population study of 312 656 women who were born in Norway during the years 1936-1964. PARTICIPANTS/MATERIALS, SETTING, METHODS: The data were obtained by two self-administered questionnaires from women who participated in the Norwegian breast cancer screening program (BreastScreen Norway) during the years 2006-2014. We used flexible parametric survival models with restricted cubic splines to estimate mean age at menarche, mean age at menopause and mean number of years between menarche and menopause according to the women's year of birth. The women who were still having menstrual periods contributed with follow-up time until the time of data collection, and the women who had reported surgical removal of the uterus and/or both ovaries prior to natural menopause contributed with follow-up time until the time of surgery. MAIN RESULTS AND THE ROLE OF CHANCE: The mean age at menarche was 13.42 years (95% CI: 13.40-13.44 years) among women born during 1936-1939, and it was 13.24 years (95% CI: 13.22-13.25 years) among women born during 1960-1964. The mean age at natural menopause increased from 50.31 years (95% CI: 50.25-50.37 years) among women born during 1936-1939 to 52.73 years (95% CI: 52.64-52.82 years) among women born during 1960-1964. The mean number of years between menarche and menopause increased from 36.83 years (95% CI: 36.77-36.89 years) to 40.22 years (95% CI: 40.11-40.34 years). LIMITATIONS, REASONS FOR CAUTION: Information about age at menarche and age at menopause was based on self-reports. WIDER IMPLICATIONS OF THE FINDINGS: Late menopause is associated with increased risk of breast cancer but also with increased life expectancy. Thus, higher mean age at menopause may partly explain the increase in breast cancer incidence after menopause and the increase in life expectancy in recent time. Also, a longer interval between menarche and menopause could suggest that the number of years of female fecundity has increased. STUDY FUNDING/COMPETING INTEREST(S): This work was funded by the South-Eastern Norway Regional Health Authority [grant number 2016112 to M.S.G.] and by the Norwegian Cancer Society [grant number 6863294-2015 to E.K.B.]. The authors declare no conflicts of interest.

Redescription of Sibling Species of Rhinoleucophenga (Diptera: Drosophilidae): R. brasiliensis and R. fluminensis.

Rhinoleucophenga Hendel comprises an unusual Drosophilidae (Diptera) genus with predaceous larvae, currently compounded by 29 nominal species with New World distribution. In the present study, Rhinoleucophenga brasiliensis (Costa Lima) and R. fluminensis (Costa Lima) are redescribed. These two species are commonly misidentified in Drosophilidae species inventories, mainly by the few morphological character details presented in the original taxonomic description. Thus, by the morphological review performed here, lectotype and paralectotypes designed to R. brasiliensis and R. fluminensis, as well as new morphological characters, drawings and photos (for the first time) are presented in order to avoid further taxonomic mistakes with those referred sibling species of Rhinoleucophenga.

Assemblage of drosophilids (Diptera, Drosophilidae) inhabiting flooded and nonflooded areas in the extreme South of Brazil

ABSTRACT Several studies on the potential use of drosophilid assemblages as bioindicator systems have been carried out in the last years. Nevertheless, the successful application of these organisms in these systems requires adequate filling of several knowledge gaps. In this sense, little is known about drosophilid assemblages in wetlands and flooded areas. The present study provides the first survey of drosophilid species inhabiting such environments in the extreme South of Brazil and compares general beta-diversity patterns between assemblages of flooded versus nonflooded areas. The specimens were collected with banana-baited traps, and the assemblages recovered in eight wetlands of the southernmost coast of Brazil were compared to those recovered from seven nonflooded areas of the Pampa and Atlantic Forest biomes. A total of 5028 and 2571 individuals encompassing 27 and 37 species were collected in the flooded and nonflooded areas, respectively. The differential species composition patterns presented between these areas was statistically supported, which seems to be related to the lower beta-diversity presented by swamps, especially in regard to dominance patterns. So, the open and climatically harsher environment provided by wetlands possibly constitutes a hostile environment for the entry and, mainly, for the persistence of several native Drosophilidae species, in contrast to some exotic and more plastic species (as Drosophila simulans and Zaprionus indianus). Since the diversity gradient of flooded areas does not seem to be related to the conservation status of the swamp, our results question the use of Drosophilidae species as bioindicators of environmental disturbance and antropic influence in wetlands.