Association Between a Woman's Age at First Birth and High Blood Pressure

The association of female reproductive factors with history of cardiovascular disease: a large cross-sectional study

BACKGROUND

This study aimed to explore the association of female reproductive factors (age at first birth (AFB), age at last birth (ALB), number of pregnancies, and live births) with history of cardiovascular disease (CVD).

METHODS

A total of 15,715 women aged 20 years or over from the National Health and Nutrition Examination Surveys from 1999 to 2018 were included in our analysis. Weighted multivariable logistic regression analysis and restricted cubic spline (RCS) model were used to evaluate the association of AFB and ALB with history of CVD in women. Additionally, the relationship between the number of pregnancies, and live births and history of CVD was also explored.

RESULTS

After adjusting for potential confounding factors, the RCS plot showed a U-curve relationship between AFB, ALB and history of CVD. Among them, AFB was associated with congestive heart failure (CHF), heart attack, and stroke in a U-shaped curve. Additionally, this U-shaped correlation also exists between ALB and CHF and stroke. However, the number of pregnancies and live births was liner positive associated with history of CVD, including coronary heart disease, CHF, angina pectoris, heart attack, and stroke.

CONCLUSIONS

Women with younger or later AFB and ALB have higher odds of CVD in later life. Further study is warranted to verify the underlying mechanisms of this association.

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 Mediating Role of Body Mass Index in the Association Between Age at First Childbirth and Lung Function Among Chinese Postmenopausal Women

Objective

Little is known about the effect of age at first childbirth on lung function. We aimed to investigate the association between age at first childbirth and lung function in Chinese women and further test whether this association is mediated by body mass index (BMI).

Methods

This cross-sectional study is a partial survey of the China Kadoorie Biobank (CKB) which was conducted in Xinxiang City, Henan Province between 2004 and 2008. A total of 16,584 postmenopausal women aged 30-79 years were enrolled. Multiple linear and logistic regression were used to investigate the association between age at first childbirth and lung function and overweight/obesity. The mediation analysis was performed using the PROCESS procedure for SPSS.

Results

The mean (SD) age at first childbirth was 23.1 (2.7) years. Women with first childbirth aged ≤19 years and 20-22 years had lower lung function than women who gave first childbirth aged 23-25 years. Per 1-year increase in the age at first childbirth was associated with a 3.31 mL increase in FEV1 (95% CI = 1.27-5.35), 3.91 mL increase in FVC (95% CI = 1.63-6.18), 0.15% increase in FEV1, % predicted (95% CI = 0.05-0.24) and 0.14% increase in FVC, % predicted (95% CI = 0.05-0.22). There was no clear association between age at first childbirth and FEV1/FVC ratio. BMI played a contribution to the association between age at first childbirth and FEV1 and the proportion was 16.4% (indirect effect: β = 0.65, 95% CI = 0.46-0.89; total effect: β = 3.96, 95% CI = 1.92-5.99). Similarly, the proportion to FVC, FEV1, % predicted, and FVC, % predicted was 25.0%, 16.6%, and 25.0%, respectively.

Conclusion

Early age at first childbirth was associated with lower lung function and BMI mediated the association. It is important to test lung function and popularize the knowledge of weight control in women who gave first childbirth at an early age.

Is first pregnancy age associated with hypertension in the Chinese rural women population?

Introduction

The purpose of this study was to investigate the relationship between first pregnancy age and hypertension later in the life of women from Chinese rural areas.

Methods

In total, 13,493 women were enrolled in the Henan Rural Cohort study. Logistic regression and linear regression were used to evaluate the association between first pregnancy age and hypertension and blood pressure indicators [including systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP)]. The restricted cubic spline was used to examine the dose-response relationship between the first pregnancy age and hypertension or blood pressure indicators.

Results

After adjusting for potential confounders, each 1-year increase in first pregnancy age was associated with a 0.221 mmHg increase in SBP values, a 0.153 mmHg increase in DBP values, and a 0.176 mmHg decrease in MAP values (all P < 0.05). The β of SBP, DBP, and MAP showed a trend of first increasing and then decreasing with increasing first pregnancy age and there was no statistical significance after first pregnancy age beyond 33 years on SBP, DBP, and MAP, respectively. A 1-year increment in first pregnancy age was associated with a 2.9% [OR (95% CI): 1.029 (1.010, 1.048)] higher odds of prevalent hypertension. The odds of hypertension increased sharply and then eventually leveled off with an increment of first pregnancy age after adjusting for potential confounders.

Conclusion

First pregnancy age might increase the risk of hypertension later in life and might be an independent risk factor for hypertension in women.

Gender-specific factors associated with hypertension among women of childbearing age: Findings from a nationwide survey in India

Background

The association of conventional (modifiable and non-modifiable) risk factors for hypertension has already been established in the literature. However, there are other putative risk factors specific to women (early menarche, age at first childbirth, women empowerment, number of children born, hysterectomy, etc.) in the development of hypertension. This study is the first study to highlight the potential association of gender-specific factors along with other conventional risk factors and hypertension, using a nationwide sample.

Methods

The study is a secondary analysis of the data collected from the National Family Health Survey-4 (NFHS-4), a nationally representative sample of 699,686 women of reproductive age in India. The interview schedule included data on general background characteristics, marriage, reproductive history, hysterectomy, knowledge, and utilization of family planning services, maternal and child care, women empowerment, non-communicable diseases, and domestic violence. The blood pressure was measured by direct observation by the study investigators using a digital blood pressure monitor. To account for disproportionate sampling and non-response, a weighted statistical analysis was performed. Logistic regression analysis was done to study the strength of the association between the risk factors and hypertension (computation of unadjusted and adjusted odds ratio).

Results

The prevalence of hypertension was 11.8% among women. Among the conventional factors, older age, higher body mass index (BMI), tobacco use, and alcohol use had higher odds for hypertension, while higher education, higher socio-economic position, and living in urban areas had lower odds. Among the gender-specific factors, younger age at first childbirth, early menarche, oral contraceptive pill use [adjusted OR: 1.23; (1.18-1.28)], and hysterectomy [adjusted OR: 1.10; (1.05-1.69)] were found to be risk factors for hypertension. Domestic violence was significantly associated with hypertension [unadjusted OR: 1.11; (1.02-1.20)]. Empowered women had lower odds of hypertension [adjusted OR: 0.93; (0.95-1.03)].

Conclusion

Significant association of these gender-specific factors among women necessitates the need for taking into account these factors while screening for hypertension among women and thus, designing a tailored model better suited to them for risk assessment.

The mediating pathways between parental separation in childhood and offspring hypertension at midlife

Social life course determinants of adult hypertension are relatively unknown. This paper examines how parental separation before age 10 relates to hypertension at age 46. Adjusting for parental confounders and considering the role of adult mediators, we aim to quantify unexplored mediating pathways in childhood using prospectively collected data. Data from the 1970 British Birth Cohort Study are utilised. Hypertension is measured by health care professionals at age 46. Potential mediating pathways in childhood include body mass index (BMI), systolic and diastolic blood pressure, illness, disability, family socioeconomic status (SES) and cognitive and developmental indicators at age 10. Additionally, we explore to what extent childhood mediators operate through adult mediators, including health behaviours, family SES, BMI and mental wellbeing. We also test for effect modification of the relationship between parental separation and hypertension by gender. Nested logistic regression models test the significance of potential mediating variables. Formal mediation analysis utilising Karlson Holm and Breen (KHB) method quantify the direct and indirect effect of parental separation on offspring hypertension at midlife. There was an association between parental separation and hypertension in mid-life in women but not men. For women, family SES and cognitive and behavioural development indicators at age 10 partly mediate the relationship between parental separation and hypertension at age 46. When adult mediators including, health behaviours, family SES, BMI and mental wellbeing are included, the associations between the childhood predictors and adult hypertension are attenuated, suggesting that these childhood mediators in turn may work through adult mediators to affect the risk of hypertension in midlife. We found family SES in childhood, cognitive and behaviour development indicators at age 10, including disruptive behaviour, coordination and locus of control in childhood, to be important mediators of the relationship between parental separation and midlife hypertension suggesting that intervening in childhood may modify adult hypertension risk.

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.

Hypertension in women: the role of adolescent childbearing

Background

Adolescent childbearing is associated with various health risks to the mother and child, and potentially with adverse socioeconomic outcomes. However, little is known about the role of adolescent childbearing in maternal health outcomes in adulthood. This study investigates the link between childbirth in adolescence and later-life risk of hypertension among women in India.

Methods

We obtained nationally representative data on demographic and health outcomes for 442,845 women aged 25 to 49 from the India National Family Health Survey (NFHS) 2015-16. We assessed the difference in hypertension prevalence between women who gave birth in adolescence (age 10 to 19) and those who did not, for the full sample and various sub-samples, using linear probability models with controls for individual characteristics, hypertension risk factors, and geographic fixed effects.

Results

Nearly 40% of the women in the sample gave birth in adolescence. The adjusted probability of being hypertensive in adulthood was 2.3 percentage points higher for this group compared to women who did not give childbirth in adolescence. This added probability was larger for women who gave birth earlier in adolescence (4.8 percentage points) and for women who gave birth more than once in adolescence (3.4 percentage points).

Conclusions

Adolescent childbearing was strongly associated with a higher probability of adult female hypertension in India. This finding illustrates the intertemporal relationship between health risk factors during the life cycle, informing the importance of addressing adverse early life events (e.g. child marriage and adolescent childbirth) for hypertension outcomes among women in India.

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.

Pregnancy history and cognitive aging among older women: the Rancho Bernardo Study

OBJECTIVE

The aim of the study was to examine the association of pregnancy history with trajectories of cognitive function in older women.

METHODS

Participants were 1,025 women (mean age = 73.1 ± 9.6 y) enrolled in the Rancho Bernardo Study who attended a clinic visit between 1988 and 1992, when pregnancy history (ever pregnant, number of pregnancies, ages at first and last pregnancy) was recorded and cognitive function was assessed with a battery of four tests repeated up to 7 times through 2016. Linear mixed-effects regression models were used to examine the association between pregnancy history and longitudinal change in cognitive function.

RESULTS

Overall, 77% of women had at least one pregnancy; number of pregnancies ranged from 1 to 14 (mean = 2.9 ± 1.7). Ages at first and last pregnancy ranged from 16 to 44 years (mean = 24.9 ± 4.7) and 16 to 49 years (mean = 30.7 ± 5.5), respectively. Of 16 associations tested (4 pregnancy exposures by 4 cognitive tests), one was statistically significant without correction for multiple comparisons. Women who reported ever being pregnant recalled 0.12 fewer words on the Buschke Selective Reminding Test for every year increase in age than women who had never been pregnant (P = 0.05). No other significant associations of pregnancy history with cognitive decline were observed.

CONCLUSIONS

Our results show no clinically meaningful long-term influence of pregnancy history on age-related change in cognitive function. These reassuring findings suggest childbearing decisions and timing will not affect cognitive function in older age.

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.

Advanced Maternal Age Worsens Postpartum Vascular Function

The age at which women experience their first pregnancy has increased throughout the decades. Pregnancy has an important influence on maternal short- and long-term cardiovascular outcomes. Pregnancy at an advanced maternal age increases maternal risk of gestational diabetes, preeclampsia, placenta previa and caesarian delivery; complications which predict worsened cardiovascular health in later years. Aging also independently increases the risk of cardiovascular disease; therefore, combined risk in women of advanced maternal age may lead to detrimental cardiovascular outcomes later in life. We hypothesized that pregnancy at an advanced maternal age would lead to postpartum vascular dysfunction. We used a reproductively aged rat model to investigate vascular function in never pregnant (virgin), previously pregnant (postpartum) and previously mated but never delivered (nulliparous) rats at approximately 13.5 months of age (3 months postpartum or equivalent). Nulliparous rats, in which pregnancy was spontaneously lost, demonstrated significantly reduced aortic relaxation responses (methylcholine [MCh] Emax: 54.2 ± 12.6%) vs. virgin and postpartum rats (MCh Emax: 84.8 ± 3.5% and 84.7 ± 3.2% respectively); suggesting pregnancy loss causes a worsened vascular pathology. Oxidized LDL reduced relaxation to MCh in aorta from virgin and postpartum, but not nulliparous rats, with an increased contribution of the LOX-1 receptor in the postpartum group. Further, in mesenteric arteries from postpartum rats, endothelium-derived hyperpolarization (EDH)-mediated vasodilation was reduced and a constrictive prostaglandin effect was apparent. In conclusion, aged postpartum rats exhibited vascular dysfunction, while rats which had pregnancy loss demonstrated a distinct vascular pathology. These data demonstrate mechanisms which may lead to worsened outcomes at an advanced maternal age; including early pregnancy loss and later life cardiovascular dysfunction.

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.