Association Between Duration of Reproductive Years and Metabolic Syndrome

Separate and combined effects of famine exposure and menarche age on metabolic syndrome among the elderly: a cross-sectional study in China

BACKGROUND

Epidemiological studies have revealed multiple risk factors for metabolic syndrome. However, there are no consistent findings on the association between famine exposure, age at menarche, and the prevalence of metabolic syndrome. This cross-sectional study aimed to reveal the individual and combined effects of famine exposure and age at menarche on the prevalence of metabolic syndrome among elderly women.

METHODS

Four thousand seven hundred seventy participants between 60 and 93 years of age were selected from the China Health and Retirement Longitudinal Study. Statistical differences between the baseline characteristics of famine exposure, age at menarche, and metabolic syndrome were evaluated using the t-test, F-test, and Chi-square test. Three multivariable-adjusted logistic regression models were used to test the association between famine exposure, age of menarche, and the odds ratio of metabolic syndrome.

RESULTS

Two thousand one hundred ninety-eight (46.08%) participants had metabolic syndrome, while 2572 (53.92%) participants did not. Furthermore, 3068 (64.32%) women reported onset of menarche under 15 years of age, while 1702 (35.68%) women reported onset of menarche above 16 years of age. Regarding the separate association of famine exposure and age of menarche with metabolic syndrome, in model three, the adolescence/adulthood famine exposure group vs. no famine exposure group odds ratio was 2.45 (95% CI 2.02, 2.97), and the older than 16 years vs. younger than 15 years group odds ratio was 1.23 (95% CI 1.09, 1.39), which was the highest odds ratio among the three models. Regarding the combined association of famine exposure and age of menarche with metabolic syndrome, in model three, among the age of menarche ≤ 15 years group, the adolescence/adulthood famine exposure vs. no famine exposure group odds ratio was 2.45 (95% CI: 1.91, 3.14); among the menarche age ≥ 16 years group, the adolescence/adulthood famine exposure stages vs. exposed group odds ratio was 3.27 (95% CI: 2.44, 4.38), which was the highest odds ratio among the three models.

CONCLUSION

These findings suggested that famine exposure and age at menarche, either separately or in combination, were positively associated with the prevalence of metabolic syndrome among older women.

Number of Births and Risk of Diabetes in China's Older Women

As an important life event in individuals' life, childbirth will affect the health of women to different degrees. More and more attention has been paid to whether the number of births will affect the incident diabetes in elderly women, but there are few related studies. Based on the data of the Chinese Longitudinal Healthy Longevity Survey in 2018, 6,159 older women are selected as the study population. Logistic regression analyses are used to estimate the relationship between the number of births and diabetes risk. For each additional birth, the odds ratio of maternal diabetes will decrease by 6.9% and the result is significant at the 1% level, especially among mothers having four children or less. The conclusion is equally applicable in the sample of fathers and urban mothers, but the increase in the number of births will increase the risk of diabetes in rural mothers, although this result is not statistically significant. Later age at first birth, later age at last birth, the longer childbearing period, and birth interval will significantly reduce the risk of diabetes.

Associations between abdominal adipose tissue, reproductive span, and brain characteristics in post-menopausal women

The menopause transition involves changes in oestrogens and adipose tissue distribution, which may influence female brain health post-menopause. Although increased central fat accumulation is linked to risk of cardiometabolic diseases, adipose tissue also serves as the primary biosynthesis site of oestrogens post-menopause. It is unclear whether different types of adipose tissue play diverging roles in female brain health post-menopause, and whether this depends on lifetime oestrogen exposure, which can have lasting effects on the brain and body even after menopause. Using the UK Biobank sample, we investigated associations between brain characteristics and visceral adipose tissue (VAT) and abdominal subcutaneous adipose tissue (ASAT) in 10,251 post-menopausal females, and assessed whether the relationships varied depending on length of reproductive span (age at menarche to age at menopause). To parse the effects of common genetic variation, we computed polygenic scores for reproductive span. The results showed that higher VAT and ASAT were both associated with higher grey and white matter brain age, and greater white matter hyperintensity load. The associations varied positively with reproductive span, indicating more prominent associations between adipose tissue and brain measures in females with a longer reproductive span. The effects were in general small, but could not be fully explained by genetic variation or relevant confounders. Our findings indicate that associations between abdominal adipose tissue and brain health post-menopause may partly depend on individual differences in cumulative oestrogen exposure during reproductive years, emphasising the complexity of neural and endocrine ageing processes in females.

Association between Reproductive Span and Sarcopenia

Sarcopenia is defined as an age-related loss of skeletal muscle and is associated with several health disorders. Causes of sarcopenia, which included physical inactivity, alcohol, dietary habits, and smoking, have been researched. The present study was undertaken to examine the association between reproductive span and sarcopenia in Korean women. Data obtained from 2008 to 2011 Korea National Health and Nutrition Examination Surveys (KNHANES) were analyzed. We defined sarcopenia based on the cut-off values of the Foundation for the National Institutes of Health (FNIH) sarcopenia project criteria: ASM/BMI < 0.512 for women. Reproductive span was defined as years from menarche to menopause, and we divided the 3970 study subjects into three groups by reproductive span tertile. Multivariate logistic regression analysis was used to determine adjusted ORs for the relation between reproductive span and sarcopenia. The prevalence of sarcopenia in the study was 17.7% (704 of 3970). Multiple logistic regression analysis was performed using weighted populations. After adjusting for covariates, reproductive span was found to be inversely associated with the risk of sarcopenia [Tertile 1 = 1 (reference); Tertile 2, odds ratio (OR) = 0.927, 95% confidence interval (CI) = 0.863–0.995; Tertile 3, OR = 0.854, 95% CI = 0.793–0.915].

Association between reproductive years and insulin resistance in middle-aged and older women: A 10-year prospective cohort study

OBJECTIVES

We hypothesized that reproductive years, a marker of total estrogen exposure, may play an important role in insulin resistance.

STUDY DESIGN

A total of 3327 middle-aged and older women (age range 40-69 years) from the Korean Genome and Epidemiology Study were included in this large prospective cohort study with a mean follow-up of 10.8 years.

MAIN OUTCOME MEASURES

Insulin resistance and sensitivity were calculated using the homeostatic model assessment of insulin resistance (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI). A linear mixed model for a repeated-measures covariance pattern with unstructured covariance within participants was used to assess longitudinal associations between baseline reproductive years and subsequent changes in HOMA-IR and QUICKI. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs) for new-onset insulin resistance according to quartiles of reproductive years.

RESULTS

Changes in HOMA-IR were significantly greater in Q1 (fewest reproductive years) than in Q4 (most reproductive years) (beta[SE] = 0.038[0.016]; p-value = 0.022), while changes in QUICKI were significantly smaller in Q1 than in Q4 (beta[SE] = -0.001[0.000]; p-value = 0.048) after adjusting for possible confounders over time. Compared with Q1, HRs (95 % CIs) for the incidence of new-onset insulin resistance were 0.807 (0.654-0.994) for Q2, 0.793 (0.645-0.974) for Q3, and 0.770 (0.622-0.953) for Q4 after adjusting for possible confounders.

CONCLUSION

A short reproductive period is associated with elevated levels on the HOMA-IR and decreased levels on the QUICKI over time. The lowest quartile of reproductive years was significantly associated with a higher risk of new-onset insulin resistance.

Duration of reproductive years and time since menopause were associated with metabolic syndrome in postmenopausal parous women of Chinese ancestry

OBJECTIVE

Although duration of reproductive years and time since menopause were previously implicated in the metabolic syndrome, the evidence is more limited. Few of the previous studies were able to take into account related reproductive variables simultaneously. The aim of the present study was to explore the influence of these two reproductive factors on the prevalence of metabolic syndrome in postmenopausal parous women from Southeast China.

METHODS

In all, 1,536 postmenopausal parous women were recruited. Self-reported information about reproductive status, including age at menarche, age at menopause, number of children, prepregnancy body weight, and oral contraceptive use, was collected, and duration of reproductive years and time since menopause were calculated. Clinical parameters related with metabolic syndrome were also measured.

RESULTS

Longer duration of reproductive years was significantly related with increased presence of the metabolic syndrome (odds ratio [OR] 1.570, 95% confidence interval [CI] 1.091, 2.259 for tertile 2 group; OR 1.850, 95% CI 1.163, 2.944 for tertile 3 group; P for trend = 0.010). Women with more than 20 years since menopause were more likely to experience metabolic syndrome (OR 2.422, 95% CI 1.109, 5.286, P = 0.026) and elevated blood pressure (OR 3.239, 95% CI 1.406, 7.458, P = 0.006) when compared with those with less than 10 years since menopause.

CONCLUSIONS

Longer duration of reproductive years and time since menopause were associated with higher prevalence of metabolic syndrome in postmenopausal parous women from Southeast China.