Age at Natural Menopause; A Data Mining Approach (Data from the National Health and Nutrition Examination Survey 2013-2014)

Background

The timing of the age at which menopause occurs varies among female populations. This variation is attributed to genetic and environmental factors. This study aims to investigate the determinants of early and late-onset menopause.

Methods

We used data from the National Health and Nutrition Examination Survey 2013-2014 for 762 naturally menopause women. Data on sociodemographic, lifestyle, examination, and laboratory characteristics were examined. We used random forest (RF), support vector machine (SVM), and logistic regression (LR) to identify important determinants of early and late-onset menopause. We compared the performance of models using sensitivity, specificity, Brier score, and area under the receiver operating characteristic (AUROC). The top determinants were assessed by using the best performing models, using the mean decease in Gini.

Results

Random forest outperformed LR and SVM with overall AUROC 99% for identifying related factors of early and late-onset menopause (Brier score: 0.051 for early and 0.005 for late-onset menopause). Vitamin B12 and age at menarche were strongly related to early menopause. Also, methylmalonic acid (MMA), vitamin D, body mass index (BMI) were among the top highly ranked factors contributing to early menopause. Features such as age at menarche, MMA, sex hormone-binding globulin (SHBG), BMI, vitamin B12 were the most important covariate for late-onset menopause.

Conclusions

Menarche age and BMI are among the important contributors of early and late-onset menopause. More research on the association between vitamin D, vitamin B12, SHBG, and menopause timing is required which will produce invaluable information for better prediction of menopause timing.

Association between age at menarche and age at menopause among women of an indigenous population of North Bengal, India

Menarche and menopause are two major components of a woman's reproductive life. Ages at menarche and menopause vary widely between and within populations and are influenced by various factors, both genetic and environmental. The present community-based cross-sectional investigation aimed to assess the association between ages at menarche and natural menopause among women belonging to the indigenous Rajbanshi population of North Bengal, India. The investigation was carried out from January 2015 to May 2015 among 510 Rajbanshi women aged between 45 and 55 years residing in the district of Darjeeling, West Bengal, India. A structured schedule was used to collect data on ages at menarche and natural menopause, marital status, parity, education, age of first and last pregnancies, duration of breastfeeding, nature of occupation, health status, smoking and monthly family income. Anthropometric measurements of height and weight were recorded and Body Mass Index (BMI) calculated. The statistical analyses, which included descriptive statistics and binary logistic regression (BLR), were done using SPSS. The women's mean age of menarche and median age of natural menopause were 12.52 years and 50 years, respectively. The BLR analysis indicated that education, age at first pregnancy had significant effects on the age at natural menopause among women who experienced menarche at <12 years of age (p<0.05). In the case of women who attained menarche at ≥12 years of age, marital status, age at last pregnancy, parity, education, duration of breastfeeding, smoking, occupation, monthly income and BMI had a greater influence on age at natural menopause. There appears to be an indirect association between age at menarche and age at natural menopause, along with different predictor variables, among the Rajbanshi women.

Association of Parity and Breastfeeding With Risk of Early Natural Menopause

IMPORTANCE

Pregnancy and breastfeeding prevent ovulation and may slow the depletion of the ovarian follicle pool. These factors may lower the risk of early menopause, a condition associated with increased risk of cardiovascular disease and other adverse health outcomes.

OBJECTIVE

To examine the association of parity and breastfeeding with the risk of early menopause.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study within the Nurses' Health Study II cohort (1989-2015) included premenopausal participants who were aged 25 to 42 years at baseline. Response rates were 85% to 90% for each cycle, and follow-up continued until menopause, age 45 years, hysterectomy, oophorectomy, death, cancer diagnosis, loss to follow-up, or end of follow-up in May 2015. Hypotheses were formulated after data collection. Data analysis took place from February to July 2019.

EXPOSURES

Parity (ie, number of pregnancies lasting ≥6 months) was measured at baseline and every 2 years. History and duration of total and exclusive breastfeeding were assessed 3 times during follow-up. Menopause status and age were assessed every 2 years.

MAIN OUTCOMES AND MEASURES

Risk of natural menopause before age 45 years.

RESULTS

At baseline, 108 887 premenopausal women aged 25 to 42 years (mean [SD] age, 34.1 [4.6] years; 102 246 [93.9%] non-Hispanic white) were included in the study. In multivariable models, higher parity was associated with lower risk of early menopause. Hazard ratios were attenuated with adjustment for breastfeeding but remained significant. Compared with nulliparous women, those reporting 1, 2, 3, and 4 or more pregnancies lasting at least 6 months had hazard ratios for early menopause of 0.92 (95% CI, 0.79-1.06), 0.84 (95% CI, 0.73-0.96), 0.78 (95% CI, 0.67-0.92), and 0.81 (95% CI, 0.66-1.01), respectively (P for trend = .006). In multivariable models also adjusted for parity, hazard ratios for duration of exclusive breastfeeding of 1 to 6, 7 to 12, 13 to 18, and 19 or more months were 0.95 (95% CI, 0.85-1.07), 0.72 (95% CI, 0.62-0.83), 0.80 (95% CI, 0.66-0.97), and 0.89 (95% CI, 0.69-1.16), respectively, compared with less than 1 month of exclusive breastfeeding (P for trend = .001). Despite the significant test for trend, estimates were not observed to be lower as duration of exclusive breastfeeding increased. In a stratified analysis of parous women, risk of early menopause was lowest among those reporting exclusive breastfeeding for 7 to 12 months in each level of parity (women with 2 pregnancies and 7-12 months of breastfeeding: HR, 0.79; 95% CI, 0.66-0.96; ≥3 pregnancies and 7-12 months of breastfeeding: HR, 0.68; 95% CI, 0.52-0.88; 2 pregnancies and ≥13 months of breastfeeding: HR, 0.87; 95% CI, 0.66-1.15; ≥3 pregnancies and 13-18 months of breastfeeding: HR, 0.86; 95% CI, 0.66-1.13; and ≥3 pregnancies and ≥19 months of breastfeeding: HR, 0.98; 95% CI, 0.72-1.32).

CONCLUSIONS AND RELEVANCE

In this study, an inverse association of parity with risk of early menopause was observed. Breastfeeding was associated with significantly lower risk, even after accounting for parity. Breastfeeding at levels consistent with current recommendations may confer an additional benefit of lower risk of early menopause.

The relation of age at menarche with age at natural menopause: a population study of 336 788 women in Norway

STUDY QUESTION

Is age at menarche associated with age at menopause or with duration of the reproductive period (interval between menarche and menopause)?

SUMMARY ANSWER

The association of age at menarche with age at menopause was weak and non-linear, and the duration of the reproductive period decreased by increasing age at menarche.

WHAT IS KNOWN ALREADY

It remains uncertain whether age at menarche is associated with age at menopause. Some studies report that women with early menarche also have early menopause. Other studies report that women with early menarche have late menopause, or they report no association. The duration of the reproductive period may be an indicator of the cumulative endogenous exposure to estrogens and progestogens during life course and is associated with risk of breast cancer and endometrial cancer.

STUDY DESIGN, SIZE, DURATION

A retrospective cohort study of 336 788 women, aged 48-71 years, in the BreastScreen Norway during the years 2006-2014 was performed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Information about age at menarche and menopausal status was obtained by self-administered questionnaires. We used time to event approaches to estimate the associations.

MAIN RESULTS AND THE ROLE OF CHANCE

Median age at menopause was 51 years in most menarche groups. Women with menarche at age 16 years or age ≥ 17 years had menopause 1 year later [median: 52 years, interquartile range (IQR): 49-54 years] than women with menarche at age 13 years (median: 51 years, IQR: 49-54 years, reference) (crude hazard ratio (HR) = 0.95; 95% CI: 0.93-0.97 and 0.95; 95% CI: 0.92-0.99, Pnon-linearity < 0.001). The reproductive period decreased with increasing age at menarche (Pnon-linearity < 0.001), and women with menarche at age ≤ 9 years had 9 years longer median reproductive period than women with menarche at age ≥ 17 years (median: 43 versus 34 years). Adjustment for year of birth did not change the HR estimates notably.

LARGE SCALE DATA

Not applicable.

LIMITATIONS, REASONS FOR CAUTION

Information about age at menarche and age at menopause was based on self-reports. Particularly for age at menarche, the long time interval between the event and data collection may have caused imprecise reporting.

WIDER IMPLICATIONS OF THE FINDINGS

Our study suggests that age at menarche is a strong indicator for the duration of women's reproductive period. Our findings should encourage studies of the independent role of duration of the reproductive period on the risk of breast cancer and endometrial cancer, since these cancers have been associated with exposure to estrogens and progestogens.

STUDY FUNDING/COMPETING INTEREST(S)

The present study was funded by the Norwegian Cancer Society [Grant number 6863294-2015]. The authors declare no conflicts of interest.

The Relationship of Fertility, Lifestyle, and Longevity Among Women

Longevity in women has been found to be associated with several reproductive factors; the age of women when they give birth, their total number of children, and the age at which they experience menopause. In the context of expectations from the evolutionary theory of aging, the focus of this study examined relationships between lifetime reproduction, age at menopause and longevity, while accounting for various lifestyle factors. The purpose of this study was to assess fertility and age at onset of menopause in 197 women of the Georgia Centenarian Study. It was hypothesized that greater lifetime reproduction would predict earlier menopause and subsequently an earlier death. An independent t test was computed to assess ethnic differences between Caucasian and African American participants. Two block-wise multiple regression analyses were computed to evaluate the impact of low socioeconomic status in childhood, the age at the time of the first childbirth, the total number of children, smoking and alcohol use, incidence of heart disease and stroke, and the age at onset of menopause on longevity. Results from this study suggest a positive association between the total number of children to the age at onset of menopause and longevity. However, when considering the lifestyle factor of smoking, the association of the total number of children to longevity is diminished.

Age at menarche predicts age at onset of major affective and anxiety disorders

BACKGROUND

Menarche age has been associated inconsistently with the occurrence, timing or severity of major depressive disorder (MDD), but rarely studied in women with bipolar (BDs) or anxiety disorders.

METHODS

We investigated women patients at a Sardinian mood disorder center for associations of age at menarche with age at illness onset for major affective or anxiety disorders, year of birth, and other selected factors, using bivariate comparisons and multivariate regression modeling.

RESULTS

Among women (n=1139) with DSM-IV MDD (n=557), BD-I (n=223), BD-II (n=178), or anxiety disorders (n=181), born in 1904-1998, of mean age 42.9 years, menarche age averaged 12.8 [CI: 12.7-12.9] years. Illness onset age averaged 30.9 [30.1-31.8] years, ranking: BD-I, 25.8; anxiety disorders, 28.0; BD-II, 30.3; MDD, 34.1 years. Menarche age declined secularly over birth years, and was associated with younger illness-onset, having no or fewer siblings, more psychiatrically ill first-degree relatives, living in rural environments, being suicidal, substance abuse, and being unemployed. Earlier menarche and earlier illness-onset were significantly associated for onset age groups of ≤ 20, 20-39, and > 40 years. Menarche age versus diagnosis ranked: BD-II<BD-I<anxiety disorders<MDD.

CONCLUSIONS

Age at menarche in Sardinia, as elsewhere, has declined over the past decades. It was strongly associated with age at onset of bipolar and anxiety, as well as major depressive disorders across the age range, suggesting sustained effects of biological maturational factors.