Impact of age at first childbirth on glucose tolerance status in postmenopausal women: the 2008-2011 Korean National Health and Nutrition Examination Survey

Reproductive factors, genetic susceptibility and risk of type 2 diabetes: A prospective cohort study

AIM

To explore the relationships of multiple reproductive factors with type 2 diabetes mellitus (T2DM) risk and the joint effects of reproductive factors and genetic susceptibility.

METHODS

We included 262,368 women without prevalent T2DM from the UK biobank. Cox proportional hazards regression models were employed to estimate the relationships of reproductive factors with T2DM risk and the joint effects of reproductive factors and genetic susceptibility.

RESULTS

During a mean follow-up of 12.2 years, 8,996 T2DM cases were identified. Early menarche (<12 years, hazard ratio (HR) 1.08 [95 % confidence interval (CI) 1.02;1.13]), late menarche (≥15 years, HR 1.11 [1.04;1.17]), early menopause (<45 years, HR 1.20 [1.12;1.29]), short reproductive lifespan (<30 years, HR 1.25 [1.16;1.35]), hysterectomy (1.31, HR [1.23;1.40]), oophorectomy (HR 1.28 [1.20;1.36]), high parity (≥4, HR 1.25 [1.17;1.34]), early age at first live birth (<20 years, HR 1.23 [1.16;1.31]), miscarriage (HR 1.13 [1.07;1.19]), stillbirth (HR 1.14 [1.03;1.27]), and ever used hormonal replacement therapy (HR 1.19 [1.14;1.24]) were related to a higher T2DM risk, while ever used oral contraceptives (HR 0.93 [0.89;0.98]) was related to a lower T2DM risk. Furthermore, women with reproductive risk factors and high genetic risk had the highest T2DM risk compared to those with low genetic risk and without reproductive risk factors.

CONCLUSION

Our findings show that multiple reproductive factors are related to T2DM risk, particularly in women with high genetic risk.

Age at first birth is associated with the likelihood of frailty in middle-aged and older women: A population-based analysis from NHANES 1999-2018

OBJECTIVES

This study examined whether age at first birth (AFB) is associated with the prevalence of frailty in middle-aged and older women.

METHODS

The study included 10,828 women (age ≥ 45 years) from the National Health and Nutrition Examination Survey (NHANES) (1999-2018) in the United States. AFB data were collected using a standardized reproductive health questionnaire. Frailty was measured using a 53-item frailty index and was diagnosed if the score on that index was over 0.21. Survey-weighted logistic regression models were used to assess the association between AFB and the prevalence of frailty. A survey-weighted restricted cubic spline (RCS) model was used to determine the dose-response relationship between AFB and frailty. Mediation analyses were performed to estimate the mediated effects of education levels, family poverty income ratio, and parity on the association between AFB and the likelihood of frailty. Finally, sensitivity and subgroup analyses were conducted to validate the robustness of our findings.

RESULTS

Among the 10,828 women, 3828 (35.4 %) had frailty. The RCS depicted a U-shaped association between AFB and frailty. Compared with the women in the reference group (AFB: 33-35 years), women in the other groups (AFB: < 18, 18-20, 21-23, and 24-26 years) had a higher likelihood of frailty, with respective odds ratios (95 % confidence intervals) of 3.02 (1.89-4.83), 2.32 (1.54-3.50), 1.83 (1.19-2.81), and 1.64 (1.07-2.53). However, no statistically significant differences were detected for women with AFB of 27-29, 30-32, or > 35 years compared with the reference group. Education levels, family poverty income ratio, and parity significantly mediated the approximately linear negative association between AFB and frailty in the subset of women with AFB of ≤32 years and the mediation proportions were 23.4 %, 32.4 %, and 18.3 %, respectively (all p < 0.001).

CONCLUSIONS

Based on our results, we conclude that early AFB is associated with a higher likelihood of frailty in middle-aged and older women.

The contributions of fertility during adolescence to disability across the life-course: hypothesized causal pathways, research gaps, and future directions

CONTEXT

Robust associations have been identified between fertility during adolescence and the disablement process, including pathologies, impairments, functional limitations and disability. Limited theoretical or empirical research considers how and why such relationships exist generally or with the individual associated components of disablement.

OBJECTIVE

To consolidate and critically evaluate literature to describe testable, theory-based hypotheses to guide future research on the mechanisms by which fertility during adolescence contributes to disablement.

METHODS

Targeted literature review of research from diverse global settings contextualised in two well-accepted theoretical frameworks in life-course epidemiology: the cumulative risk model and the critical period approach.

RESULTS

Five hypothesised causal pathways linking adolescent fertility to disablement in later life are described: 1) Causal relationship initiated by fertility during adolescence; 2) Common cause(s) for both, such as adverse childhood experiences; 3) Contributing cause(s) to adolescent fertility; 4) Interaction between adolescent fertility and other risk factors; and 5) Critical period effects unique to adolescence. Most research on the topic is on pathologies versus functional limitations and disability.

CONCLUSION

We highlight promising research avenues to inform future research and interventions on adolescent fertility and the disablement process. This work provides theoretical clarity, identifies research gaps, and offers hypotheses-testing opportunities for future research.

The association of female reproductive factors with risk of metabolic syndrome in women from NHANES 1999-2018

BACKGROUND

Female reproductive factors such as age at first birth (AFB), age at last birth (ALB), number of pregnancies and live births play an essential role in women's health. However, few epidemiological studies have evaluated the association between female reproductive factors and metabolic syndrome (MetS). We therefore conducted a cross-sectional study to investigate the association between MetS risk and female reproductive factors.

METHODS

We investigated the relationship between AFB, ALB, number of pregnancies and live births and the incidence of MetS using publicly available data from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018. Weighted multivariable logistic regression analysis, restricted cubic spline (RCS) model, and subgroup analysis were used to evaluate the association between AFB and ALB and the risk of MetS in women. In addition, the relationship between the number of pregnancies, live births and MetS risk was also explored.

RESULTS

A total of 15,404 women were included in the study, and 5,983 (38.8%) had MetS. RCS models showed an N-shaped relationship between AFB and MetS risk, whereas ALB, number of pregnancies, and live births were linearly associated with MetS. Weighted multivariable logistic regression analysis showed that the number of live births was associated with MetS risk, with ORs of 1.18 (95% CI: 1.04, 1.35) for women with ≥ 5 deliveries compared to women with ≤ 2 births.

CONCLUSIONS

AFB was associated with the risk of MetS in an N-shaped curve in women. In addition, women with high live births have a higher incidence of MetS.

Genetic liability to age at first sex and birth in relation to cardiovascular diseases: a Mendelian randomization study

BACKGROUND

Growing evidence suggests that various reproductive factors, including early menarche, early menopause, and age at first birth, may increase the risk of developing cardiovascular disease (CVD) later in life. However, the associations between reproductive factors and CVDs are inconsistent and controversial. Therefore, we conducted a two-sample Mendelian randomization (MR) analysis to explore the potential links between age at first sex (AFS) and age at first birth (AFB) and several CVDs.

METHODS

We obtained summary statistics for exposure from the largest genome-wide association studies of AFS and AFB. To serve as instrumental variables, we selected 259 SNPs associated with AFS and 81 SNPs associated with AFB at the genome-wide significance level. We employed a random-effects inverse-variance weighted method to pool estimates, and conducted multivariable MR analysis to determine the direct association between AFS and AFB with CVDs, while accounting for the effects of confounders.

RESULTS

The genetic liability to later AFS was associated with decreased risks of heart failure (odd ratio [OR] 0.700; 95% confidence interval [CI] 0.639-0.767; p = 2.23 × 10^-14), coronary artery disease (OR 0.728; 95% CI 0.657-0.808; p = 1.82 × 10^-9), myocardial infarction (OR 0.731; 95% CI 0.657-0.813; p = 8.33 × 10^-9), stroke (OR 0.747; 95% CI 0.684-0.816; p = 6.89 × 10^-11), and atrial fibrillation (OR 0.871; 95% CI 0.806-0.941; p = 4.48 × 10^-4). The genetic liability to later AFB was also associated with decreased risks of CVDs, including myocardial infarction (OR 0.895; 95% CI 0.852-0.940; p = 8.66 × 10^-6), coronary heart disease (OR 0.901; 95% CI 0.860-0.943; p = 9.02 × 10^-6), heart failure (OR 0.925; 95% CI 0.891-0.961; p = 5.32 × 10^-5), and atrial fibrillation (OR 0.944; 95% CI 0.911-0.978; p = 0.001). However, no association was found between AFB and stroke. The associations remained independent from the effects of AFS and AFB on potential confounders, including smoking, alcohol intake, body mass index, and depression. Mediation analysis suggested that education attainment partly mediates the link from AFS and AFB to CVD outcomes.

CONCLUSION

Our results observed a causal relationship between later AFS, AFB and lower CVDs risk; it emphasizes the importance of providing sex education since early sex and birth may have undesirable effects. Cardiovascular risk stratification that considers reproductive factors may help address CVD risk.

Intersections between adolescent fertility and obesity-pathways and research gaps focusing on Latin American populations

Latin America has notably elevated rates of adolescent fertility and obesity in women. Although numerous studies document associations between adolescent fertility and obesity across the life course, the pathways explaining their association are insufficiently theorized, especially regarding the factors in Latin America that may underpin both. Additionally, much of the existing research is from high-income countries, where fertility and obesity are trending down. In this paper, we review the various complex pathways linking adolescent fertility and obesity, highlighting research gaps and priorities, with a particular focus on Latin American populations. We carefully consider pregnancy's distinct impact on growth trajectories during the critical period of adolescence, as well as the cumulative effect that adolescent fertility may have over the life course. We also articulate a pathway through obesity as it may contribute to early puberty and thus, to adolescent fertility. If obesity is a cause of adolescent fertility, not a result of it, or if it is a mediator of early-life exposures to adulthood obesity, these are critical distinctions for policy aiming to prevent both obesity and early fertility. Research to better understand these pathways is essential for prevention efforts against obesity and undesired adolescent fertility in Latin America.

Identification of 371 genetic variants for age at first sex and birth linked to externalising behaviour

Age at first sexual intercourse and age at first birth have implications for health and evolutionary fitness. In this genome-wide association study (age at first sexual intercourse, N = 387,338; age at first birth, N = 542,901), we identify 371 single-nucleotide polymorphisms, 11 sex-specific, with a 5-6% polygenic score prediction. Heritability of age at first birth shifted from 9% [CI = 4-14%] for women born in 1940 to 22% [CI = 19-25%] for those born in 1965. Signals are driven by the genetics of reproductive biology and externalising behaviour, with key genes related to follicle stimulating hormone (FSHB), implantation (ESR1), infertility and spermatid differentiation. Our findings suggest that polycystic ovarian syndrome may lead to later age at first birth, linking with infertility. Late age at first birth is associated with parental longevity and reduced incidence of type 2 diabetes and cardiovascular disease. Higher childhood socioeconomic circumstances and those in the highest polygenic score decile (90%+) experience markedly later reproductive onset. Results are relevant for improving teenage and late-life health, understanding longevity and guiding experimentation into mechanisms of infertility.

Childbearing age is correlated with components of metabolic syndrome and parameters of insulin resistance in Chinese menopausal women

OBJECTIVE

To assess the relationship between childbearing age and elements of metabolic syndrome (MS) among menopausal women in China.

MATERIALS AND METHODS

One thousand one hundred and forty-one subjects were divided into four interim average childbearing age (ACA) groups: ≥16 < 24 years old, ≥24 < 29 years old, ≥29 < 34 years old, and ≥34 years old. The group with the lowest prevalence of MS was used as a control. Body mass index, waist circumference (WC) and waist-to-hip ratio were assessed. Plasma glucose, lipids, glycated hemoglobin (HbA1c) and fasting insulin (FINS) were measured. Insulin resistance (IR) was assessed using the homeostasis model assessment (HOMA) method.

RESULTS

The prevalence of MS in the 16-24 and 29-34 age groups was higher than that in the control group (p < .05). Compared with the control group, the odds ratios of MS were 1.431 for the 16-24 group (p < .05) and 1.553 for the 29-34 group (P < 0.01). ACA was correlated with FINS, HOMA-IR, WC, fasting plasma glucose, and triglycerides independent of age (p < .05).

CONCLUSIONS

Average childbearing age was correlated with parameters of IR and components of MS independent of age in Chinese menopausal women.

Association between gravidity and risk of metabolic syndrome: Results of Tabari cohort study

BACKGROUND AND AIMS

The purpose of the present study was to investigate the association of gravidity and age at first pregnancy with metabolic syndrome in a large-scale, population-based cohort study in Iran.

METHODS

The present secondary analysis was conducted on a subset of the population (5739 women with at least one pregnancy) enrolled in the Tabari cohort study. Reproductive history was collected using a structured questionnaire. The relationship of gravidity and age at first pregnancy with metabolic syndrome and its components was analyzed using the logistic regression model.

RESULTS

The results showed that after adjustment for confounding variables, the odds of having metabolic syndrome was not significantly associated with age at first pregnancy (P = 0.269) and gravidity (P = 0.504). However, there was an association between hypertension and age at first pregnancy (OR = 0.32, 95% CI = 0.12-0.82; P = 0.03). Additionally, waist circumference was also associated with gravidity (OR = 2.17, 95% CI = 1.37-3.35).

CONCLUSION

As the findings indicated, age at first pregnancy and gravidity were not associated with the odds of having metabolic syndrome. However, a relationship was found between first pregnancy at the age of >35 years and the decreased risk of hypertension. Gravidity was also found to be a dose-dependent risk factor for increased waist circumference.

Risk of 16 cancers across the full glycemic spectrum: a population-based cohort study using the UK Biobank

INTRODUCTION

Diabetes is observed to increase cancer risk, leading to hypothesized direct effects of either hyperglycemia or medication. We investigated associations between glycosylated hemoglobin (HbA1c) across the whole glycemic spectrum and incidence of 16 cancers in a population sample with comprehensive adjustment for risk factors and medication.

RESEARCH DESIGN AND METHODS

Linked data from the UK Biobank and UK cancer registry for all individuals with baseline HbA1c and no history of cancer at enrollment were used. Incident cancer was based on International Classification of Diseases - 10th Edition diagnostic codes. Age-standardized incidence rates were estimated by HbA1c category. Associations between HbA1c, modeled as a restricted cubic spline, and cancer risk were estimated using Cox proportional hazards models.

RESULTS

Among 378 253 individuals with average follow-up of 7.1 years, 21 172 incident cancers occurred. While incidence for many of the 16 cancers was associated with hyperglycemia in crude analyses, these associations disappeared after multivariable adjustment, except for pancreatic cancer (HR 1.55, 95% CI 1.22 to 1.98 for 55 vs 35 mmol/mol), and a novel finding of an inverse association between HbA1c and premenopausal breast cancer (HR 1.27, 95% CI 1.00 to 1.60 for 25 vs 35 mmol/mol; HR 0.71, 95% CI 0.54 to 0.94 for 45 vs 35 mmol/mol), not observed for postmenopausal breast cancer. Adjustment for diabetes medications had no appreciable impact on HRs for cancer.

CONCLUSIONS

Apart from pancreatic cancer, we did not demonstrate any independent positive association between HbA1c and cancer risk. These findings suggest that the potential for a cancer-inducing, direct effect of hyperglycemia may be misplaced.

Association between age at first childbirth and type 2 diabetes in Chinese women

AIMS/INTRODUCTION

The present study aims to explore the relationship between age at first childbirth and developing type 2 diabetes, and analyze potential modifiers of its relationship.

MATERIALS AND METHODS

The data were obtained from the baseline survey of a large-scale cohort study in 10 diverse areas of China. Multivariate logistic regressions were used to analyze the association between developing type 2 diabetes and the age at first childbirth. Adjustments were made in each model on sociodemographic, socioeconomic and reproductive covariates. Subgroup analyses were further carried out to investigate the effects of reproductive factors, body mass index at 25 years of age and hypertension on the above-mentioned association.

RESULTS

Women who have their first child at age <20 years (odds ratio [OR] 1.33, 95% confidence interval [CI] 1.22-1.44) and between the ages of 20 and 24 years (OR 1.16, 95% CI 1.10-1.23) were more likely to be diagnosed with type 2 diabetes compared with those who have their first child between the ages of 25 and 29 years; equal to or more than three parities (OR 1.44, 95% CI 1.30-1.60), premenopausal status (OR 1.58, 95% CI 0.99-2.54), overweight at age 25 years (OR 1.62, 95% CI 1.37-1.93) and hypertension (OR 1.37, 95% CI 1.22-1.53) are all conditions found to increase the odds of developing type 2 diabetes in those who have their their first child at an early age (<20 years).

CONCLUSIONS

The study concluded that having the first child at an early age is associated with an increased likelihood of developing type 2 diabetes later in life; reproductive factors, overweight at age 25 years and status of hypotension could modify such an association.

The relationships between timing of first childbirth, parity, and health-related quality of life

PURPOSE

A few studies have investigated the relationship between age at first childbirth and health-related quality of life (HRQoL). This study examined the relationship between age at first childbirth and HRQoL and whether parity mediates this timing of the first childbirth-HRQoL relationship in women aged 50 years or above.

METHODS

The study population included 5146 parous women ≥ 50 years in the cross-sectional survey, the Korea National Health and Nutrition Examination Survey 2010-2012. HRQoL was evaluated by the EuroQol five-dimensional descriptive system. Participants were grouped according to quartiles of age at first childbirth (ranges: 13-21, 22-23, 24-25, and 26-44 years). This study used linear regression analysis to examine the relationship between age at first childbirth and HRQoL and on each dimension. Mediation analysis was used to examine the contribution of age at first childbirth to HRQoL and to each dimension.

RESULTS

This study found the increasing pattern of HRQoL across quartiles of age at first childbirth (P for trend = 0.030). Odds of problems in self-care and anxiety/depression dimensions significantly increased across the quartiles. Women with later age at first childbirth tended to have better HRQoL (B = 0.352, P = 0.003); parity significantly contributed to this relationship. Decreasing parity accounted for 33.5% of the relationship between late first childbirth and increased HRQoL. Early age at first childbirth significantly increased odds of the mobility problem through increasing parity.

CONCLUSIONS

Women of an early age at first childbirth tended to have lower HRQoL through giving more deliveries. Our findings suggest that more attention needs to be given to women with early pregnancy and more delivery to prevent impaired HRQoL.

Increasing prevalence of diabetes mellitus in a developing country and its related factors

BACKGROUND

All countries, irrespective of their developmental stage, face an increasing burden of non-communicable diseases including diabetes mellitus. There is substantial evidence of the existence of the gap in the level of diabetes mellitus and its complications prevention and control measures in developing countries. This study aimed to assess the prevalence of diabetes mellitus in urban and rural dwellers in a low-income country from both younger and older population and to identify factors related.

METHODS

This is a community based comparative cross-sectional study conducted in a low-income country, Ethiopia. The sample size was determined by EPI-Info for two populations; the WHO's STEP-wise approach for non-communicable diseases surveillance in developing countries was employed for sampling, study variable selection and data collection procedures. Fasting blood glucose levels were measured by finger pricking after overnight fasting. Data entry was done by EPI-data computer program version 3.1 and then processed by SPSS version 20. Bivariate and multivariate logistic regression tests were used to assess the associations between diabetes status of individuals and its potential predictor variables. P-value < 0.05 was considered as statistically significant level.

RESULT

The study was conducted on 1405 individuals with age range of 18-97 years old. The mean fasting blood glucose level for study participants was 91.16mg/dl; while it was 94.73mg/dl for urban and 87.71mg/dl for rural dwellers. The prevalence of diabetes mellitus was 3.3%; while it was 2.0% for rural and (4.6%) for urban dwellers. Both the mean blood glucose level and the prevalence of diabetes mellitus were significantly higher for urban residents than rural. More than three-fourths of diabetic cases were newly diagnosed by this study. Urban dwellers, centrally obese, overweight, and hypertensive individuals have higher odds of getting diabetes mellitus.

CONCLUSIONS AND RECOMMENDATIONS

High prevalence of diabetes mellitus involving both old and young population was documented. Most diabetic cases were suddenly diagnosed during this survey. The problem is noticeably alarming, attention should be given to the control and prevention of diabetes mellitus and related complications.

Adolescent Childbirth Is Associated With Greater Framingham Risk Scores for Cardiovascular Disease Among Participants of the IMIAS (International Mobility in Aging Study)

BACKGROUND

Previous studies observe associations between lifetime parity and cardiovascular disease, but relatively fewer investigate age at first childbirth (AFB). Herein, we examine the association of AFB with a summary cardiovascular risk measure (Framingham Risk Score [FRS]).

METHODS AND RESULTS

As part of the IMIAS (International Mobility in Aging Study), data were collected in 2012 among 1047 women, aged 65 to 74 years, from Canada, Albania, Colombia, and Brazil. FRSs were calculated to describe cardiovascular risk profiles, and linear regression analyses were performed, adjusting for early life and socioeconomic variables. Women with an AFB of <20 years were compared with women with an AFB of 20 to 24, 25 to 29, and ≥30 years, as well as nulliparous women. We also compared FRS between combinations of AFB and parity categories: nulliparous women, parity 1 to 3 combined with AFB <20 years, parity ≥4 with AFB <20 years, parity 1 to 3 with AFB ≥20 years, and parity ≥4 with AFB ≥20 years. Women with an AFB of <20 years had a higher mean FRS compared with all other AFB groups. Compared with the lowest AFB risk group (25-29 years), women with an AFB of <20 years had a 5.8-point higher mean FRS (95% confidence interval, 3.4-8.3 points). Nulliparous women presented the lowest mean FRS in all analyses. The analysis comparing combinations of AFB and parity categories showed no meaningful differences in FRS between women who had 1 to 3 childbirths and those who had ≥4 childbirths within the stratum of AFB <20 years, and in the stratum of AFB ≥20 years.

CONCLUSIONS

Our analyses suggest that nulliparity and AFB, rather than increasing parity, drive the association with cardiovascular disease risk.

Impact of age at first childbirth on primary open-angle glaucoma

OBJECTIVE

No studies have addressed the relationship between the timing of first childbirth and primary open-angle glaucoma (POAG). The aim of the study was to identify the relationship between age at first childbirth and POAG and to examine the contribution of parity to the age at first childbirth-POAG relationship in postmenopausal women.

METHODS

The study population comprised postmenopausal women aged 50 or above in the cross-sectional Korea National Health and Nutrition Examination Survey from 2010 to 2012. Participants were grouped into quintiles by age at first childbirth for analysis. This study used logistic regression and mediation analyses with accommodations for the complex sampling structure of the survey.

RESULTS

Of the 4,057 women in the study population, the mean age at first childbirth was 23.7 years, and POAG prevalence was 3.4%. Prevalence of POAG was lowest in women whose first childbirth was between the ages of 27 and 44 (1.8%). Their risk for POAG (odds ratio [OR], 0.25; 95% CI, 0.10-0.65) was significantly lower than in those whose first childbirth was between the ages of 13 and 20, after adjustments for covariates. Late first delivery (≥27 y) was directly (OR, 0.57) and totally (OR, 0.85) associated with the decreased risk of POAG; decreased parity in women who delivered their first child at an older age attenuated the age at first childbirth-POAG relationship (OR of indirect effect, 1.50).

CONCLUSIONS

First childbirth at the age of 27 years or above decreases the risk of POAG in postmenopausal women. Decreased parity, caused by late first childbirth, attenuated the magnitude of the total effects of age at first childbirth on POAG.

Timing of first childbirth and age-related cataract

OBJECTIVE

No studies investigated the effects of age at first childbirth on cataract formation. This study was performed to determine the relationships of age at first childbirth to age-related cataract in postmenopausal women.

METHODS

Study population included 7,021 postmenopausal women in the Korea National Health and Nutrition Examination Survey, 2008 to 2012. Participants were subdivided in quartiles according to the age at first childbirth as follows: 13 to 21, 22 to 23, 24 to 25, and 26 to 44 years. We used odds ratios (ORs) and 95% confidence intervals (CIs) to address the relationships between age at first childbirth and age-related cataract with adjustments for confounders.

RESULTS

Mean participants' age and age at first childbirth were 64.4 and 23.6 years, respectively. The prevalence of any subtype of age-related cataract was 64.9%. Nuclear cataract prevalence was significantly higher in postmenopausal women with later age at first childbirth (24-25 and 26-44 years) compared with those with the earliest age at first childbirth (13-21 years): ORs (95% CIs) were 1.23 (1.05-1.45) and 1.24 (1.05-1.46), respectively. A significant linear trend across quintile was observed (P = 0.006). Age at first childbirth linearly 4% (OR 1.04, 95% CI 1.01-1.06) and 2% (OR 1.02, 95% CI 1.00-1.04) increased risk for nuclear and cortical cataract formation, respectively. The population-attributable fraction of nuclear cataract caused by the first childbirth at 24 years or later was 4.9% (95% CI 1.20%-8.59%, P = 0.009).

CONCLUSIONS

Later age of first childbirth was independently associated with higher risks of nuclear and cortical cataract in postmenopausal women. Further prospective studies are needed to elucidate the role of age at first childbirth in developing age-related cataract.

Age at First Childbirth and Hypertension in Postmenopausal Women

Whether age at first childbirth has an effect on hypertension incidence is unclear. The objectives of this study were to examine the relationship between age at first childbirth and hypertension and to examine whether degree of obesity, measured as body mass index, mediates age at first childbirth-related hypertension in postmenopausal women. This study analyzed 4779 postmenopausal women data from the Korea National Health and Nutrition Examination Survey 2010 to 2012. Logistic regression analyses were used to investigate relationship between age at first childbirth and hypertension. Mediation analysis was performed to examine the contribution of body mass index to age at first childbirth-related hypertension. Mean of participants’ age at first childbirth and current age were 23.8 and 63.4 years, respectively. The prevalence of hypertension was 51.1%. Age at first childbirth was significantly associated with the prevalence of hypertension (odds ratio, 0.963; 95% confidence interval, 0.930–0.998; P =0.036). Women with age at first childbirth ≤19 years had significantly higher risk of hypertension (odds ratio, 1.61; 95% confidence interval, 1.17–2.23; P =0.004) compared with those >19 years. Multivariable-adjusted prevalence of hypertension was significantly lower in women who delivered the first infant at 20 to 24 (45.5%), 25 to 29 (46.1%), and ≥30 (39.9%) years compared with those at ≤19 years (58.4%). Body mass index completely mediated age at first childbirth–hypertension relationship (indirect effect: odds ratio, 0.992; 95% confidence interval, 0.987–0.998; P =0.008). Age at first childbirth was significantly associated with hypertension in postmenopausal women. Body mass index mediated the effects of age at first childbirth on hypertension.

Age at first childbirth and newly diagnosed diabetes among postmenopausal women: a cross-sectional analysis of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

CONTEXT AND OBJECTIVE:

It has been reported that earlier age at first childbirth may increase the risk of adult-onset diabetes among postmenopausal women, a novel finding with important public health implications. To date, however, no known studies have attempted to replicate this finding. We aimed to test the hypothesis that age at first childbirth is associated with the risk of adult-onset diabetes among postmenopausal women.

DESIGN AND SETTING:

Cross-sectional analysis using baseline data from 2919 middle-aged and elderly postmenopausal women in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

METHODS:

Age at first childbirth was determined from self-reporting and newly diagnosed diabetes through a 2-hour 75-g oral glucose tolerance test and/or glycated hemoglobin. Logistic regression was performed to examine associations between age at first childbirth and newly diagnosed diabetes among postmenopausal women.

RESULTS:

We did not find any association between age at first childbirth and diabetes, either when minimally adjusted for age, race and study center (odds ratio, OR [95% confidence interval, CI]: ≤ 19 years: 1.15 [0.82-1.59], 20-24 years: 0.90 [0.66-1.23] and ≥ 30 years: 0.86 [0.63-1.17] versus 25-29 years; P = 0.36) or when fully adjusted for childhood and adult factors (OR [95% CI]: ≤ 19 years: 0.95 [0.67-1.34], 20-24 years: 0.78 [0.56-1.07] and ≥ 30 years: 0.84 [0.61-1.16] versus 25-29 years; P = 0.40).

CONCLUSION:

Our current analysis does not support the existence of an association between age at first childbirth and adult-onset diabetes among postmenopausal women, which had been reported previously.

Long-term effects of oral contraceptives on the prevalence of diabetes in post-menopausal women: 2007-2012 KNHANES

There is little information on whether past use of oral contraceptives (OCs) at child-bearing age influences the incidences of diabetes and insulin resistance (IR) after menopause. This study aimed to evaluate the association of past use of OCs with the development of diabetes and IR in post-menopausal women. This cross-sectional study was based on data from the Korea National Health and Nutrition Examination Survey carried out from 2007 to 2012. Of the 50405 participants, 6554 post-menopausal women were included in the analysis. The associations of OC use with the prevalence of diabetes in post-menopausal women were examined using multivariate logistic analysis. In addition, fasting glucose and insulin levels were measured in 3338 nondiabetic post-menopausal women, and the association between IR and OCs was examined by the analysis of covariance. The prevalence of diabetes was significantly higher in post-menopausal participants who had taken OCs for more than 6 months than in those who had never taken OCs. The association remained significant after adjusting for multiple confounding factors (odd ratio 1.379; 95 % CI 1.115-1.707; P = 0.003). The duration of OC use was also positively associated with the prevalence of diabetes. Furthermore, taking OCs for more than 6 months led to a significant increase in fasting insulin levels and HOMA-IR in nondiabetic participants. Past use of OCs for more than 6 months led to a significant increase in the prevalence of diabetes in post-menopausal women, and increased IR in nondiabetic participants. These results suggested that the prolonged use of OCs at reproductive age may be an important risk factor for developing diabetes in post-menopausal women.

Impact of adolescent pregnancy on hypertension in postmenopausal women

OBJECTIVE

Several studies have reported the detrimental effects on maternal health due to pregnancy during adolescence, but no studies have reported the influence of adolescent pregnancy on blood pressure in women's later life.

METHOD

We investigated whether there was an association between adolescent pregnancy and the risk of hypertension in Korean postmenopausal women. This study used the data of 2538 postmenopausal women from the Korean National Health and Nutrition Examination Survey in 2010-2011. Multivariate logistic regression analyses were used to evaluate the independent association between adolescent pregnancy and hypertension by adjusting for potential confounding factors.

RESULTS

Postmenopausal women with a history of adolescent pregnancy had a higher prevalence of hypertension than those without a history of adolescent pregnancy. After fully adjusting for potential confounding factors such as age, lifestyle, sociodemographic factors, known hypertension risk factors, and reproductive factors, a history of adolescent pregnancy was significantly associated with hypertension (odds ratio, 1.702; 95% confidence interval, 1.125-2.574).

CONCLUSION

This study showed that a history of adolescent pregnancy is significantly and independently associated with a higher risk of hypertension in postmenopausal women.

Effect of maternal age at childbirth on insulin resistance: the 2010 Korean National Health and Nutrition Examination Survey

OBJECTIVE

This study aimed to assess insulin resistance according to maternal age at childbirth.

PATIENTS AND METHODS

The data used in this study were obtained from the 2010 Korean National Health and Nutrition Examination Survey. This study included a total of 2233 nondiabetic female subjects ≥30 years of age that were subdivided into groups according to their obesity and abdominal obesity (AOB) statuses. The homoeostasis model assessment of insulin resistance (HOMA-IR) was used to quantify the insulin resistance according to age at first childbirth and last childbirth.

RESULTS

Age at first childbirth showed a negative relationship with HOMA-IR in both the nonobese and non-AOB groups, while age at last childbirth showed a positive relationship with HOMA-IR in both the nonobese and non-AOB groups. A multivariate logistic regression analysis revealed that ages at first and last childbirth were significantly associated with the highest HOMA-IR quartile. The odds ratio was 0·9 (95% confidence interval: 0·82-0·98) for age at first childbirth, and 1·07 (95% confidence interval: 1·01-1·14) for age at last childbirth in the nonobese and non-AOB groups.

CONCLUSION

In conclusion, this study suggests that insulin resistance is increased in females who experienced their first childbirth at a younger age or their last childbirth at a later age, particularly in nonobese individuals. Because these data suggest that childbearing age could be an independent risk factor for diabetes, a high-quality prospective study assessing the relationship between childbearing age and insulin resistance should be performed.

Maternal age at first delivery is associated with the risk of metabolic syndrome in postmenopausal women: from 2008-2010 Korean National Health and Nutrition Examination Survey

Background

Recent cross-sectional studies demonstrated that earlier maternal age at first childbirth is correlated with a higher risk of diabetes in postmenopausal women. In this study, we evaluated whether the age at first delivery is associated with the risk of metabolic syndrome (MetS) in postmenopausal women.

Methods

A total of 4,261 postmenopausal women aged 45 years or older were analyzed using data generated from Korea National Health and Nutrition Examination Surveys (2008–2010). Subjects were divided into three groups according to the maternal age at first delivery as follows: ≤ 20 years (n=878), 21-25 years (n=2314), and ≥ 26 years (n=1069).

Results

Approximately 37% of subjects had MetS. The prevalence of MetS showed a gradual increase as maternal age at first delivery decreased (≥ 26 years = 30.9% vs. 21-25 years = 39.9% vs. ≤ 20 years = 50.8%, respectively, p < 0.001). Central obesity indices such as trunk fat mass and waist circumference were significantly higher in the group aged ≤ 20 years than other groups. After adjustments for confounding factors, the odds ratios (ORs) for predicting the presence of MetS increased gradually as first delivery age decreased (≥ 26 years vs. 21-25 years vs. ≤ 20 years: OR [95% CI] = 1 vs. 1.324 [1.118-1.567] vs. 1.641 [1.322-2.036], respectively). Among components of MetS, younger maternal age at first delivery (≤ 20 years) was significantly associated with increased waist circumference (OR [95% CI] = 1.735 [1.41-2.13]), elevated blood pressure (1.261 [1.02-1.57]), high triglyceride (1.333 [1.072-1.659]), and low HDL-cholesterol (1.335[1.084-1.643]).

Conclusions

Our findings suggest that younger maternal age at first delivery is independently associated with a higher risk of central obesity and MetS in postmenopausal women.