Socioeconomic position, lifestyle factors and age at natural menopause: a systematic review and meta-analyses of studies across six continents

Abstract

Background: Age at natural menopause (ANM) is considered a marker of biological ageing and is increasingly recognized as a sentinel for chronic disease risk in later life. Socioeconomic position (SEP) and lifestyle factors are thought to be associated with ANM.Methods: We performed a systematic review and meta-analyses to determine the overall mean ANM, and the effect of SEP and lifestyle factors on ANM by calculating the weighted mean difference (WMD) and pooling adjusted hazard ratios. We explored heterogeneity using meta-regression and also included unpublished findings from the Australian Longitudinal Study on Women’s Health.Results: We identified 46 studies across 24 countries. Mean ANM was 48.8 years [95% confidence interval (CI): 48.3, 49.2], with between-study heterogeneity partly explained by geographical region. ANM was lowest among African, Latin American, Asian and Middle Eastern countries and highest in Europe and Australia, followed by the USA. Education was associated with later ANM (WMD middle vs low education 0.30, 95% CI: 0.10, 0.51; high vs low education 0.64, 95% CI 0.26, 1.02). A similar dose-response relationship was also observed for occupation. Smoking was associated with a 1-year reduction of ANM (WMD: -0.91, 95% CI: –1.34, –0.48). Being overweight and moderate/high physical activity were modestly associated with later ANM, but findings were less conclusive.Conclusions: ANM varies across populations, partly due to differences across geographical regions. SEP and some lifestyle factors are associated with ANM, but further research is needed to examine the impact of the associations between risk factors and ANM on future health outcomes.

Dietary intake and adequacy of energy and nutrients in Mexican older adults: results from two National Health and Nutrition Surveys

“…Consequences of malnutrition such as frailty, sarcopenia, osteoporosis and chronic morbidity will be experienced by the older adult at an earlier age, only because of his/her socioeconomic condition. 39 It has been reported that the SFFQ instrument underestimates energy intake. OA are more vulnerable to memory bias and underreport energy.…”

Associations between lifetime tobacco exposure with infertility and age at natural menopause: the Women's Health Initiative Observational Study

“…For age at natural menopause, several recent large prospective studies and meta-analyses reiterate the effects of active smoking on the timing of menopause 31 33–36. Biologically, tobacco toxins negatively affect the hormonal milieu through differing mechanisms, and various studies have investigated levels of oestrone, oestradiol, oestriol, progesterone, follicle-stimulating hormone, luteinising hormone, and anti-Müllerian hormone (a direct measure of ovarian reserve); the results predict an early end to the reproductive life of the ovaries and uterus in women exposed to active smoke and SHS 7–10 37–39.…”

“…Age at menarche was included in models examining age at natural menopause. Potential confounders were primarily chosen based on a review of the literature discussed above, and we included potential confounders commonly used in analyses related to these outcomes 31. Potential confounders considered but not in the final adjustment models were age at first and last term birth, any induced abortions, parity, number of term births, income at baseline, BMI at 35 years and very hard exercise 3 or more times per week at 35 years.…”

Physiological Aspects of Female Fertility: Role of the Environment, Modern Lifestyle, and Genetics

“…It is unclear how these translate for the woman that smokes cigarettes while attempting to conceive; however, it is known that smoking leads to a reduction in ovarian reserve and an advancement of the age of menopause for the woman (167,301), potentially due to the influence of polycyclic hydrocarbons which are activated into more toxic metabolites by the liver (49,271). Further human studies have demonstrated that oocytes derived from cigarette smoking women undergoing IVF treatment have a greater number of immature oocytes (385), an increased thickness of the zona pellucida (310), with follicles containing higher level of markers of oxidative stress within the follicular fluid (252), and within the cumulus (316).…”