From Menarche to Menopause: Trends among US Women Born from 1912 to 1969

Abstract

The authors investigated secular trends in age at menarche, age at menopause, and reproductive life span within a population-based cohort of US women. Study subjects were 22,774 women selected randomly as controls for a case-control study. Eligible controls were residents of Wisconsin, Massachusetts, or New Hampshire born between 1910 and 1969. Subjects completed telephone interviews in 1988-2001 and answered questions regarding reproductive and lifestyle factors. Birth cohorts were created using 5- and 10-year periods, and statistical comparisons were performed with analysis of variance. The mean age at menarche decreased by approximately 6 months for those born between 1910 and 1949 (13.1 vs. 12.7 years; p < 0.001), with a subsequent increase to 13.0 years among women born between 1960 and 1969 (p < 0.001). Among naturally menopausal women aged 60 or more years who reported never use of postmenopausal hormone therapy, the authors observed a 17-month increase in the mean age at menopause for those born between 1915 and 1939 (49.1 vs. 50.5 years; p = 0.001) after adjustment for potential confounders. They also observed an increase in the average number of reproductive years (subtracting age at menarche from age at natural menopause), from 36.1 years among women born between 1915 and 1919 to 37.7 years among the 1935-1939 cohort (p = 0.0001). These findings have implications for women's lifetime exposure to circulating endogenous hormones.

The Quality of Life During and After Menopause Among Rural Women

“…This median age at menopause appeared to be within the ranges which were observed in the western countries [6]. In a population-based cohort of over 22 000 women from three regions of the US, the median age of natural menopause was found to be 50.5 years [7]. A review article which was written by Palacios et al showed that the median age at menopause in Europe ranged from 50.1 to 52.8 years, that in north America, it ranged from 50.5 to 51.4 years, that in Latin America, it ranged from 43.8 to 53 years, and that in Asia, it ranged from 42.1 to 49.5 years [8].…”

Secular Trends in Hip Fractures Worldwide: Opposing Trends East Versus West

“…Other factors such as the average increase in the number of reproductive years reported in women in the United States (80) and in Hong Kong (68) may have played a role in the trend breaks observed in women, but would not explain parallel changes in hip fractures in men. Other contributors, such as smoking cessation, (90) improvement in physical activity, (91) calcium intake and vitamin D status, (25,92) and fall prevention, (68,93,94) could have also influenced, to a limited extent, the hip fracture rates.…”

“…(79,80) Increased urbanization could also reflect an associated increase in prosperity and access to medical care, which could, theoretically, increase survival of the frailest elderly, as was recently proposed as a possible contributor to the increase in fracture rates among older Korean women. (81) Of equal interest are the declining rates of fractures now being observed in North America, Europe, Hong Kong, and Taiwan.…”

Role of an MDM4 polymorphism in the early age of onset of nasopharyngeal carcinoma

“…As the polymorphism may be in linkage disequilibrium with another allele, an alternative locus may be the true functional polymorphism. Previous studies have indicated that there is a major haplotype of the human MDM4 (14,15). This haplotype is tagged by several SNPs, which are in high linkage disequilibrium, across the MDM4 gene, including the polymorphic locus rs1563828.…”