BackgroundEarly life-stage exposure to estrogen increases the risk of breast cancer. The objective of this study was to investigate the age at menarche and time to onset of regular menstrual cycles for Japanese women born between 1930 and 1985.MethodsA cross-sectional study was designed using data from the baseline survey of the Japan Nurses’ Health Study. The data from 48,104 female nurses were analyzed. To view trends in age at menarche, the distribution of age at menarche was calculated for each birth year cohort. The distribution of time to onset of regular menstrual cycles was calculated for each birth year cohort. To estimate whether high-risk group of the estrogenic dependent disorders increase with succeeding generations, we defined the women who experienced menarche at ten years old or younger and started a regular cycle within one year as early age onset of ovulatory cycles.ResultsAverage ages at menarche were as follows: 13.8 years for those born in the 1930s (n = 113), 13.3 years for the 1940s (n = 4,751), 12.8 years for the 1950s (n = 15,844), 12.3 years for the 1960s (n = 20,547), 12.2 years for the 1970s (n = 6,568), and 12.2 years for the 1980s (n = 281). The proportion of women who experienced the onset of regular menstrual cycles 1 year after menarche was 29.3% for those born in the 1930s, but decreased to 11.9% for the 1980s. On the other hand, the proportion of women who did not have regular menstrual cycles was 10.4% for those born in the 1930s, but rose to 19.8% in 1980s. The proportion of women who experienced menarche at 10 years old and started regular menstrual cycles within one year increased over time: the percentage was 0.0%, 0.4%, 0.6%, 1.1%, 1.3%, and 2.1% for the women born in 1930s, 1940s, 1950s, 1960s, 1970s, and 1980s, respectively.ConclusionsThe age at menarche of Japanese women born between 1930 and 1985 decreased, but the onset of regular menstrual cycling is delayed; so that the distribution of the start time of ovulatory cycles may have spread for younger generations. Those suggest that the high-risk group of estrogenic dependent diseases among Japanese women may increase in the near future.

The Japan Nurses' Health Study (JNHS) is a prospective occupational cohort study investigating the effects of lifestyle and healthcare practices on women's health. It was initiated in 2001, with a six-year entry period and a proposed ten-year follow-up. Participants comprise female registered nurses, licensed practical nurses, public health nurses, and midwives, aged 25 yr or over at the baseline survey. Participants were recruited in cooperation with the Japanese Nursing Association and the Japan Menopause Society. A self-administered baseline questionnaire was distributed, requesting demographic information, lifestyle factors, pharmaceutical drug use, physical condition, reproductive health, and disease history. A total of 49,914 women from all 47 prefectures in Japan responded to the baseline survey. Among them, approximately 18,000 agreed to be followedup, and returned signed informed-consent sheets, together with their completed baseline questionnaires. Changes in lifestyle, healthcare, incidence of disease, and health outcomes over time will now be studied. The cohort receives annual JNHS newsletters and biennial follow-up questionnaires by mail.

BackgroundSmoking during pregnancy causes obstetric and fetal complications, and smoking cessation may have great benefits for the mother and the child. However, some pregnant women continue smoking even in pregnancy.ObjectiveTo review the literature addressing the prevalence of smoking during pregnancy, explore psychosocial factors associated with smoking, and review the evidence of psychosocial interventions for smoking cessation during pregnancy in recent years.Literature reviewComputerized Internet search results in PubMed for the years spanning from 2004 to 2014, as well as references cited in articles, were reviewed. A search for the keywords “smoking cessation pregnancy” and “intervention” and “clinical trials” yielded 52 citations. Thirty-five citations were identified as useful to this review for the evidence of psychosocial interventions for smoking cessation during pregnancy.ResultsThe prevalence of smoking during pregnancy differs by country, reflecting the countries’ social, cultural, and ethnic backgrounds. Women who had socioeconomic disadvantages, problems in their interpersonal relationships, higher stress, depression, less social support, and who engaged in health-risk behaviors were more prone to smoking during pregnancy. Psychosocial interventions, such as counseling, are effective methods for increasing smoking cessation.ConclusionSmokers may have various psychosocial problems in addition to health problems. It is important to understand each individual’s social situation or psychosocial characteristics, and a psychosocial intervention focused on the characteristics of the individual is required.

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