Reproductive history and post-reproductive mortality: A sibling comparison analysis using Swedish register data

Unplanned births and their effects on maternal Health: Findings from the Constances Cohort

Unplanned births remain relatively common, even in regions with high contraceptive prevalence and accessible abortion services, such as contemporary France. Previous studies have shown that unplanned births can have numerous negative consequences for the well-being of mothers and children, including poorer maternal health behaviors, delayed and insufficient prenatal care, and depression during or immediately after pregnancy. However, these studies do not provide conclusive evidence on whether the observed outcomes are a consequence of unplanned births or of the conditions in which they likely occur. Furthermore, scant attention has been given to other dimensions of maternal well-being, such as physical health. This study uses longitudinal data from the French Constances Cohort and applies fixed-effects event study models to examine how women's self-rated general health and risk of depressive symptoms are affected in the years following an unplanned birth. Results show that women who had an unplanned birth reported a sudden, significant drop in their general health in the year following the birth, particularly among the youngest, while health outcomes following planned births showed a gradual, slight decrease over the time-period considered. The risk of depressive symptoms increased similarly after birth for both unplanned and planned births. This study contributes to the literature by using a longitudinally constructed measure of unplanned births based on pre-birth fertility intentions, rather than commonly used retrospective measures prone to ex post rationalization. It also distinguishes between unwanted and mistimed births while further examining their consequences on medium-term maternal health.

Parity and post-reproductive mortality among U.S. Black and White women: Evidence from the health and retirement study

Population health research finds women's mortality risk associated with childlessness, low parity (one child), and high parity (6+ children) in a U-shaped pattern, although U.S. studies are inconsistent overall and by race/ethnicity. Parity, however, is contingent on women's biophysiological likelihood of (in)fecundity as well as voluntary control practices that limit fertility. No studies have empirically examined infecundity differentials among women and their potential contribution to the parity-post-reproductive mortality relationship or the race/ethnic-related mortality gap. We examine 7,322 non-Hispanic Black and White women, born 1920-1941, in the Health and Retirement Study, using zero-inflation methods to estimate infecundity risk and parity by race/ethnicity. We estimate proportional hazards models [t0 1992/1998, t1 2018] to examine associations of infecundity risk, parity, early-life-course health and social statuses, and post-reproductive statuses with all-cause mortality. We find Black women's infecundity probability to be twice that of White women and their expected parity 40% higher. Infecundity risk increases mortality risk for all women, but parity-post-reproductive mortality associations differ by race/ethnicity. White women with one and 5+ children (U-shaped curve) have increased mortality risk, adjusting for infecundity risk and early-life factors; further adjustment for post-reproductive health and social status attenuates all parity-related mortality risk. Black women's parity-post-reproductive mortality associations are not statistically significant. Black women's post-reproductive mortality risk is anchored in earlier-life conditions that elevate infecundity risk. Results suggest a need to focus upstream to better elucidate race/ethnic-related social determinants of reproductive health, infecundity, parity, and mortality.

Fertility and self-rated health of migrant women of childbearing age-an analysis of moderating effects based on socioeconomic status

BACKGROUND

As fertility rates continue to decline and negative population growth emerges, China has sequentially introduced encouraging fertility policies to raise fertility levels. The impact of fertility on women's health remains inconclusive. It is essential to explore further the correlation between fertility and the health status of 113 million migrant women of childbearing age in China.

OBJECTIVE

To investigate how fertility affects the health status of migrant women of childbearing age and determine if migrant women's socioeconomic status plays a moderating role in this process.

METHODS

Using a nationally representative dataset from the 2018 China Migrants Dynamic Survey (CMDS), we examined the effects of fertility on the self-rated health of migrant women of childbearing age. An ordinary least squares regression model with moderating effects was used for the empirical study, and robustness tests were conducted based on the ordered probit model and propensity score matching to address endogeneity.

RESULTS

The empirical results indicated that a rise in the number of children born significantly reduces the self-rated health of migrant women of childbearing age. An increase in years of schooling and household income can significantly mitigate the negative impact of childbearing on the health of migrant women. The robustness of the above results was validated through alternative models and propensity score matching (PSM) methods. The heterogeneity analysis revealed that fertility exerts a negative impact on the health status of migrant women with rural household registration and on the health status of inter-provincial and inter-city migrant women. Further investigation found that the occurrence of childbirth during migration and an increase in the number of girls significantly negatively impacted the health status of migrant women. In contrast, the increase in the number of boys did not show a significant effect. Improving the health of migrant women of childbearing age significantly positively impacted their future childbearing intentions.

CONCLUSIONS

Migrant women of childbearing age bear the dual burden of migration and childbirth. Our findings showed the rise in the number of children born and the occurrence of childbirth during migration posed greater challenges to the health status of female migrants, particularly among those with lower socioeconomic status. Government and community efforts for enhancing health among migrant women of childbearing age are recommended.

Birth Spacing and Parents' Physical and Mental Health: An Analysis Using Individual and Sibling Fixed Effects

An extensive literature has examined the relationship between birth spacing and subsequent health outcomes for parents, particularly for mothers. However, this research has drawn almost exclusively on observational research designs, and almost all studies have been limited to adjusting for observable factors that could confound the relationship between birth spacing and health outcomes. In this study, we use Norwegian register data to examine the relationship between birth spacing and the number of general practitioner consultations for mothers' and fathers' physical and mental health concerns immediately after childbirth (1-5 and 6-11 months after childbirth), in the medium term (5-6 years after childbearing), and in the long term (10-11 years after childbearing). To examine short-term health outcomes, we estimate individual fixed-effects models: we hold constant factors that could influence parents' birth spacing behavior and their health, comparing health outcomes after different births to the same parent. We apply sibling fixed effects in our analysis of medium- and long-term outcomes, holding constant mothers' and fathers' family backgrounds. The results from our analyses that do not apply individual or sibling fixed effects are consistent with much of the previous literature: shorter and longer birth intervals are associated with worse health outcomes than birth intervals of approximately 2-3 years. Estimates from individual fixed-effects models suggest that particularly short intervals have a modest negative effect on maternal mental health in the short term, with more ambiguous evidence that particularly short or long intervals might modestly influence short-, medium-, and long-term physical health outcomes. Overall, these results are consistent with small to negligible effects of birth spacing behavior on (non-pregnancy-related) parental health outcomes.

Non-standard family histories and wellbeing at older ages

The life course approach emphasizes that health and wellbeing at older ages are influenced by experiences occurred in the previous stages of life. We contribute to the literature by focusing on the role of the non-standardness of family histories and argue that individuals who experienced non-standard trajectories have been exposed to social sanctions throughout their life course with negative long-term consequences on wellbeing. In our study, non-standardness of family histories is the extent an individual's family history differs from those of the others within reference groups, defined combining birth cohort, gender and country of residence. Family histories between age of 15 and 49 are analyzed using Sequence Analysis, thus accounting for events related to fertility and union formation (marriage and cohabitation) and dissolution, and their timing. Dissimilarities between family sequences are measured using optimal matching and are standardized within the reference groups. We use retrospective data from the seventh wave of the Survey of Health Ageing and Retirement in Europe (SHARE) and estimate linear regression models to assess the association between non-standardness of family histories and older people's life satisfaction. Quality of life and depressive symptoms are examined in additional analyses. A negative association is found between non-standardness of family histories and wellbeing, which is stronger for lower educated individuals and in Southern European countries. Results are consistent with the idea that uncommon family behaviors may have a long-term negative effect on wellbeing. Individual resources and a more tolerant societal context can reduce or eliminate the negative consequences of engaging in non-standard family behaviors.

Reproduction as a window to future health in women

Cultivating awareness for reproduction as a window to future health presents an opportunity for early identification and modification of risk factors that can affect both individual and population-level morbidity and mortality. Infertility could serve as both a window into future health as well as a pathway to future pathology. The underlying mechanisms of infertility may share common pathways with long-term risk for health and well-being. Making this identification early in the disease process may improve opportunities for intervention, and deepen our understanding of long-term risk. Additionally, fertility treatments may increase individual risk. Only by making these associations and designing studies to understand how disease and treatment risk impact health can we truly fulfill our goal of building healthy families. The aim of this review is to discuss the short-term impact of fertility challenges and treatment, long-term associations of infertility with morbidity and mortality, and the role of parity in modifying these risk associations.

Exploring the associations between number of children, multi-partner fertility and risk of obesity at midlife: Findings from the 1970 British Cohort Study (BCS70)

BACKGROUND

Early parenthood, high parity, and partnership separation are associated with obesity. However, the emergence of non-marital partnerships, serial partnering and childbearing across unions, means that it is important to consider their association to obesity. This paper examined the associations between number of biological children and multi-partner fertility (MPF)-defined as having biological children with more than one partner, with obesity at midlife.

METHOD

The sample consisted of 2940 fathers and 3369 mothers in the 1970 British Cohort Study. The outcome was obesity (BMI 30 or over) at age 46. Fertility and partnership histories ascertained the number of live biological children and MPF status by age 42. The associations were tested using logistic regression adjusting for confounders at birth, age 10 and age 16. Adult factors recorded at age 42 including age at first birth, smoking status, alcohol dependency, educational attainment and housing tenure were considered as mediators.

RESULTS

For fathers, obesity odds did not differ according to number of children or MPF. In unadjusted models, mothers with one child (OR 1.24 95%CI 1.01-1.51), mothers who had two children with two partners (OR 1.45 95%CI 1.05-1.99), and mothers who had three or more children with two or more partners (OR 1.51 95%CI 1.18-1.93) had higher odds of obesity. In adjusted models, there remained an association between mothers with one child and odds of obesity (OR 1.30 95%CI 1.05-1.60). All other associations were attenuated when confounders were included.

CONCLUSIONS

Mothers who had children with multiple partners had higher odds of obesity. However this association was completely attenuated when parental and child confounders were accounted for; suggesting that this association may be explained by confounding. Mothers who had one child only may be at increased odds of obesity, however this could be due to multiple factors including age at first birth.

Maternal age at birth of last child and cardiovascular disease mortality later in life among a national cohort of postmenopausal women from the United States

Maternal age at last birth of child is increasing in the United States, and it has been reported to influence future chronic diseases. In this study of nationally-representative sample of postmenopausal women, there was no conclusive association between maternal age at last birth of child and cardiovascular disease mortality later in life.

Objective

Maternal age at last birth (ALB) of child is increasing in the United States, and it has been reported to influence future chronic diseases. However, the relationship of ALB and cardiovascular disease (CVD) events later in life has not been widely studied. We evaluated the association of ALB with CVD mortality.

Methods

Data were from 7,971 parous postmenopausal women older than 45 years who participated in the US National Health and Nutritional Examination Survey from 1999 to 2018 and had mortality follow-up data through to December 31, 2019. ALB was self-reported, whereas CVD mortality was assessed using International Classification of Diseases codes. Cox regression was used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI).

Results

The mean age of participants was 63 ± 9.8 years, with 9.5% being non-Hispanic Black, 9.7% being Hispanic women, and 21% reporting ALB ≥35 years. During a median follow-up of 8.1 years, 443 participants died from CVD. In age-adjusted models, CVD mortality was elevated for women with ALB of <25 years (HR, 1.68; 95% CI, 1.23-2.29) and ALB of ≥35 years (HR, 1.37; 95% CI, 1.00-1.88). However, after additional adjustment for race and ethnicity, foreign born, education, marital status, poverty income ratio, parity, smoking status, age at menarche, oral contraceptive pills use and family history of myocardial infarction, these estimates were attenuated resulting in no association between ALB and CVD mortality.

Conclusions

In this study of nationally representative sample of postmenopausal women, there was no conclusive association between maternal ALB and CVD mortality later in life.

Parity and hypertension risk in couples: does number of parity matter: findings from Tehran Lipid and Glucose Study

BACKGROUND AND AIMS

As reported, hypertension (HTN) plays a leading role in explaining mortality worldwide, but it still has many confounding factors. This study explored whether the number of parity and age matters for HTN among couples from the Tehran Lipid and Glucose Study (TLGS).

METHODS

This study was conducted on 2851 couples from TLGS. All the variables were collected based on the standard protocol. The participants were categorized into four and five categories according to the number of parity (childless, one, two, three, or more parities) and age (18-30y, 30-40y, 40-50y, 50-60y, and 60-70y), respectively. Spline regression models via log link function for the binary outcome and linear link function for continuous outcomes were applied to evaluate the effect of interaction term age and parity categories on the desired outcome.

RESULTS

Among the total of 2851 pairs, 2.3% had no child, 9.5% had 1 child, 38.4% had 2 children, and 49.8% had ≥ 3 children. The adjusted risk (95% CI) of HTN in females aged 40-50y with 1 child, 2 and ≥ 3 children compared to no child were 1.14(1.04, 1.26), 1.05(1.01, 1.10), 1.12(1.07, 1.17), respectively (p < 0.05). Moreover, in those aged 50-60y with 2 and ≥ 3 children, the risk of HTN significantly increased by 4%. In females aged 60-70y with ≥ 3 children compared to those without children, the risk of HTN increased by 2%. For males aged 30-40y with 2 children compared to the no child group, the adjusted risk of HTN increased by 17%, while for those with ≥ 3 children in the same age group, this risk significantly decreased by 13%. Moreover, in males aged 30-40y with 2 children, risk ratio of HTN increased by 17%, but in males with ≥ 3 children, it decreased by 13% and in those in the same groups but aged 40-50y the risk increased by 6% and 11%, respectively.

CONCLUSION

Our findings suggest that gender, childlessness, having one child, and multi-parity had different impacts on HTN. Further research is needed to confirm our findings.

Health outcomes of only children across the life course: An investigation using Swedish register data

Only children (with no full biological siblings) are a growing subgroup in many high-income settings. Previous studies have largely focused on the short-term developmental outcomes of only children, but there is limited evidence on their health outcomes. Using Swedish population register data for cohorts born 1940-75, we compare the health of only children with that of children from multi-child sibling groups, taking into account birth order, family size, and presence of half-siblings. Only children showed lower height and fitness scores, were more likely to be overweight/obese in late adolescence, and experienced higher later-life mortality than those with one or two siblings. However, only children without half-siblings were consistently healthier than those with half-siblings, suggesting that parental disruption confers additional disadvantages. The health disadvantage was attenuated but not fully explained by adjustment for parental characteristics and after using within-family maternal cousin comparison designs.

Mothers of small-bodied children and fathers of vigorous sons live longer

Life-history traits (traits directly related to survival and reproduction) co-evolve and materialize through physiology and behavior. Accordingly, lifespan can be hypothesized as a potentially informative marker of life-history speed that subsumes the impact of diverse morphometric and behavioral traits. We examined associations between parental longevity and various anthropometric traits in a sample of 4,000-11,000 Estonian children in the middle of the 20th century. The offspring phenotype was used as a proxy measure of parental genotype, so that covariation between offspring traits and parental longevity (defined as belonging to the 90th percentile of lifespan) could be used to characterize the aggregation between longevity and anthropometric traits. We predicted that larger linear dimensions of offspring associate with increased parental longevity and that testosterone-dependent traits associate with reduced paternal longevity. Twelve of 16 offspring traits were associated with mothers' longevity, while three traits (rate of sexual maturation of daughters and grip strength and lung capacity of sons) robustly predicted fathers' longevity. Contrary to predictions, mothers of children with small bodily dimensions lived longer, and paternal longevity was not linearly associated with their children's body size (or testosterone-related traits). Our study thus failed to find evidence that high somatic investment into brain and body growth clusters with a long lifespan across generations, and/or that such associations can be detected on the basis of inter-generational phenotypic correlations.

Life-course fertility and multimorbidity among middle-aged and elderly women in China: Evidence from China health and retirement longitudinal study

Background

Multimorbidity has become an important public health problem in China, especially among middle-aged and elderly women. Few studies have been reported on the association between multimorbidity and female fertility, which is an important stage in the life course. This study aimed to explore the association between multimorbidity and fertility history among middle-aged and elderly women in China.

Methods

Data from 10,182 middle-aged and elderly female participants in the China Health and Retirement Longitudinal Study (CHARLS) in 2018 were used in this study. Multimorbidity was defined as the presence of at least two or more chronic conditions. Logistic regression analysis, negative binomial regression analysis, and restrictive cubic splines (RCSs) were used to analyze the relationship between female fertility history and multimorbidity or the number of chronic conditions. Multivariable linear regression was used to analyze the relationship between female fertility history and multimorbidity pattern factor scores.

Results

The results of this study showed that high parity and early childbearing were significantly associated with an increased risk of multimorbidity and an increased number of chronic conditions among middle-aged and elderly women in China. Late childbearing was significantly associated with reduced risk of multimorbidity and lessened diseases. Parity and age of first childbirth were significantly correlated with the odds of multimorbidity. The association between fertility history and multimorbidity was found to be influenced by age and urban-rural dual structure. Women with high parity tend to have higher factor scores of cardiac-metabolic, visceral-arthritic, and respiratory-psychiatric patterns. Women with early childbearing tended to have higher factor scores of the visceral-arthritic pattern and those with late childbearing tended to have lower factor scores of the cardiac-metabolic pattern.

Conclusion

Fertility history has a significant effect on multimorbidity in the middle and later lives of Chinese women. This study is of great importance for reducing the prevalence of multimorbidity among Chinese women through their life course and promoting health during their middle and later lives.

Fertility experiences and later-life cognitive function among older adults in China

OBJECTIVES

The relationship between fertility history and human health has long fascinated scholars; however, whether there is a link between number of children and cognitive function in older adults remains unclear. We investigated the associations between parity and the timing of first and last births with the cognitive function of older adults over 65.

METHODS

The mini-mental state examination (MMSE) was selected as a tool to measure cognitive function. We analyzed data on 5847 older adults in rural and urban communities in China from the 2018 Chinese Longitudinal Healthy Longevity Survey using ordinary least squares. To further explore the transmission mechanism, we also conducted a mediating effect analysis.

RESULTS

We found a negative association between number of children and cognitive function in older adults. Compared with older adults with four children, the MMSE scores of older adults with more than five children decreased significantly, and the score of older adults with zero to three children increased. Further, a late age at first birth (≥35) and a late age at last birth (≥35) were negatively associated with cognitive function. We also found that the associations between parity and cognition might be partly explained by variations in health.

CONCLUSION

Our analyses provided evidence from China to support the link between fertility history and cognitive function that has been observed in previous international studies: We suggest that high parity (≥5) is negatively associated with cognitive function.

Number of Births and Later-Life Depression in Older Adults: Evidence from China

Previous studies on the number of births and the health of the elderly have been highly focused on physical health and used samples from developed countries. Therefore, this study aimed to explore the effect of the lifetime number of births on depression in Chinese older adults. We used panel data for men and women aged 50 and over from the 2013-2018 China Health and Retirement Longitudinal Study. Depressive symptoms were assessed through a short form of the Center for Epidemiologic Studies Depression Scale. We found that depression levels in women were significantly higher than in men, with a mean difference of 2.44 (p < 0.001). The model estimation results indicated that the number of births affected depression in older adults, and its increase could exacerbate depression in older adults. The number of births significantly impacted depression among the elderly aged 50-69. Furthermore, there was a negative relationship between the proportion of sons and older adults' depression, which was significant in older males; the number of abortions may exacerbate depression in older adults, especially in females.

The association between reproductive history and the multidimensional health of older adults in rural China and its gender differences: Evidence from the Chinese longitudinal healthy longevity survey

Background

Few studies have examined the association between reproductive history and the multidimensional health of older adults with more diverse reproductive histories and poorer health status in rural China. The purpose of this study is to explore the effect of parity, sex ratio of children and late childbearing on multidimensional health and its gender differences.

Methods

The analytical sample consisted of 3,377 older adults in rural China who participated in the Chinese Longitudinal Healthy Longevity Survey (CLHLS) in 2018. Linear regression models were applied to estimate the relationship between reproductive history and multidimensional health, with separate models for each indicator of health outcomes.

Results

Older adults in rural areas with greater parity were more likely to have better cognitive function (β = 0.409, 95% CI: 0.255–0.563), fewer Activities of Daily Living (ADL) limitations (β = −0.085, 95% CI: −0.137 to −0.034) and symptoms of depression (β = −0.396, 95% CI: −0.577 to −0.216). The social mechanism of intergenerational support from children later in life partly explained the positive effect of parity. Late childbearing had negative effects on cognitive function (β = −1.220, 95% CI: −1.895 to −0.545), ADL (β = 0.253, 95% CI: 0.028–0.478) and symptoms of depression (β = 1.025, 95% CI: 0.237–1.812). Women were more likely to be influenced by the positive effect of parity; the association between late childbearing and health was only significant in the male group.

Conclusions

Parity and late childbearing are associated with cognitive function, activities of daily living, and symptoms of depression in the older adults in rural China. Older adults with more children might be in better health, and this finding is especially significant in women. However, late childbearing had a negative effect on multidimensional health, especially for men. The social mechanism and gender differences between reproductive history and health need to be further explored.

Fertility decline and the emergence of excess female survival in post-reproductive ages in Italy

In Italy, at least in the cohorts born up to the beginning of the twentieth century, women’s mortality in post-reproductive ages was influenced by fertility, with large progenies (and, to a lesser extent, childlessness) leading to markedly lower survival chances. This relationship proved strong enough to affect the female-to-male ratio in old age as fertility declined. In this paper, we show that various measures of extra female survival at high ages are closely connected to the fertility transition in Italy, and to its peculiar historical and geographical evolution.

Association between Parenthood and Health Behaviour in Later Life-Results from the Population-Based CARLA Study

Previous research has focused on comparing health behaviour between parents and non-parents at younger ages, while little is known about the impact of being a parent on health behaviours in later life. We studied whether parenthood is associated with later physical activity (PA), dietary pattern, smoking status and alcohol consumption in German adults of middle and old age. We used data from the baseline examination of the population-based CARLA-study in Halle (Saale), comprising 1779 adults aged 45-83. Linear and logistic regression analyses assessed the relationship between parenthood and health behaviours while controlling for age, partner status, education, income, occupational position, socioeconomic status in childhood, and number of chronic diseases. Of the participants, 89.1% had biological children. Being a father was associated with higher PA in sports (sport index ß = 0.29, 95% confidence interval [0.14; 0.44]), but not with PA in leisure time (excluding sports), dietary pattern, consumption of alcohol and smoking status. No associations were found between being a mother with all outcome variables. Provided that PA of fathers is typically reduced when the children are young, the development towards higher PA at later age needs to be studied in more detail.

Higher Parity Is Associated With Lower Mortality in a European Population of Women With High Fertility: Results From Ireland

Research has often found a U- or J-shaped association between parity and mortality. Many researchers have suggested repeated pregnancy, childbirth, and lactation taxes the body beyond a certain parity level. Available research has concentrated on populations with controlled fertility or historic populations. Ireland presents an opportunity to explore these associations in a modern sample with high fertility. We use data from the Irish Longitudinal Study on Ageing (TILDA) to test whether parity is associated with mortality in women aged 50 years or over (n = 4177). We use Cox proportional hazards models to model survival and adjust for demographics and early life circumstances. We test whether a number of health characteristics mediate these effects. Models were also stratified by birth cohort to test possible cohort effects. Higher parity was associated with lower risk of mortality, even after adjustment for early life and socioeconomic circumstances. This effect was not mediated by current health characteristics. The effects were largely driven by those born between 1931 and 1950. Increasing parity is associated with decreasing mortality risk in this sample. The effects of parity could not be explained through any of the observed health characteristics. These findings are in contrast to much of the literature on this question in similar populations. Lack of fertility control in Ireland may have "selected" healthier women into high parity. Social explanations for these associations should be further explored.

Development and validation of a risk prediction index for severe maternal morbidity based on preconception comorbidities among infertile patients

OBJECTIVE

To develop and validate a preconception risk prediction index for severe maternal morbidity (SMM), defined by the Centers for Disease Control and Prevention as indicators of a life-threatening complication, among infertile patients.

DESIGN

Retrospective analysis of live births and stillbirths from 2007 to 2017 among infertile women.

SETTING

National commercial claims database.

PATIENT(S)

Infertile women identified on the basis of diagnosis, testing, or treatment codes.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The primary outcome was SMM, identified as any indicator from the Centers for Disease Control and Prevention Index except blood transfusion alone, which was found to overestimate cases. Twenty preconception comorbidities associated with a risk of SMM were selected from prior literature. Targeted ensemble learning methods were used to rank the importance of comorbidities as potential risk factors for SMM. The independent strength of the association between each comorbidity and SMM was then used to define each comorbidity's risk score.

RESULT(S)

Among 94,097 infertile women with a delivery, 2.3% (n = 2,181) experienced an SMM event. The highest risk of SMM was conferred by pulmonary hypertension, hematologic disorders, renal disease, and cardiac disease. Associated significant risks were lowest for substance abuse disorders, prior cesarean section, age ≥40 years, gastrointestinal disease, anemia, mental health disorders, and asthma. The receiver operating characteristic area under the curve for the developed comorbidity score was 0.66. Calibration plots showed good concordance between the predicted and actual risk of SMM.

CONCLUSION(S)

We developed and validated an index to predict the probability of SMM on the basis of preconception comorbidities in patients with infertility. This tool may inform preconception counseling of infertile women and support maternal health research initiatives.

Association between infertility and all-cause mortality: analysis of US claims data

BACKGROUND

The consequences of an infertility diagnosis extend beyond the pursuit of family building, because women with infertility also face increased risks for severe maternal morbidity, cancer, and chronic disease.

OBJECTIVE

This study aimed to examine the association between female infertility and all-cause mortality.

STUDY DESIGN

This retrospective analysis compared 72,786 women with infertility, identified in the Optum Clinformatics Datamart from 2003 to 2019 by infertility diagnosis, testing, and treatment codes, with 3,845,790 women without infertility seeking routine gynecologic care. The baseline comorbidities were assessed using the presence of ≥1 metabolic syndrome diagnoses and the Charlson Comorbidity Index. The primary outcome, which was all-cause mortality, was identified by linkage to the Social Security Administration Death Master File outcomes and medical claims. The association between infertility and mortality was examined using a Cox proportional hazard regression by adjusting for age, hypertension, hyperlipidemia, type II diabetes, year of evaluation, smoking, number of visits per year, nulliparity, obesity, region of the country, and race.

RESULTS

Among 16,473,458 person-years of follow-ups, 13,934 women died. Women with infertility had a 32% higher relative risk for death from any cause (0.42% vs 0.35%, adjusted hazard ratio, 1.32; 95% confidence interval, 1.18-1.48) than women without infertility. The mean follow-up time per patient was 4.0±3.7 years vs 4.2±3.8 years for women with and without infertility, respectively. When stratified by age of <35 or ≥35 years or baseline medical comorbidity, the association between infertility and mortality remained. Women with infertility who delivered a child during the follow-up period faced a similar increased risk for mortality than the overall infertile group. Finally, receiving fertility treatment was not associated with a higher risk for death than receiving an infertility diagnosis or testing alone.

CONCLUSION

Although the absolute risk for death was low in both groups, women with infertility faced a higher relative risk for mortality than women without infertility. The association remained across all age, race and ethnicity groups, morbidities, and delivery strata. Importantly, infertility treatment was not associated with an increased risk for death. These findings reinforce the disease burden associated with infertility and its potential for long-term sequelae.

The association between parity, CVD mortality and CVD risk factors among Norwegian women and men

BACKGROUND

Several studies have shown that women and men with two children have lower mortality than the childless, but there is less certainty about mortality, including CVD mortality, at higher parities and meagre knowledge about factors underlying the parity-mortality relationship.

METHODS

The association between parity and CVD mortality was analyzed by estimating discrete-time hazard models for women and men aged 40-80 in 1975-2015. Register data covering the entire Norwegian population were used, and the models included a larger number of relevant sociodemographic control variables than in many previous studies. To analyze the relationship between parity and seven CVD risk factors, logistic models including the same variables as the mortality models were estimated from the CONOR collection of health surveys, linked to the register data.

RESULTS

Men (but not women) who had four or more children had higher mortality from CVD than those with two, although this excess mortality was not observed for the heart disease sub-group. Overweight, possibly in part a result of less physical activity, seems to play a role in this. All CVD risk factors except smoking and alcohol may contribute to the relatively high CVD mortality among childless.

CONCLUSIONS

Childbearing is related to a number of well-known CVD risk factors, and becoming a parent or having an additional child is, on the whole, associated with lower-or at least not higher-CVD mortality in Norway. However, for men family sizes beyond three children are associated with increased CVD mortality, with risks of overweight one possible pathway.

The risk of developing a meningioma during and after pregnancy

Pregnancy has been associated with diagnosis or growth of meningiomas in several case reports, which has led to the hypothesis that pregnancy may be a risk factor for meningiomas. The aim of this study was to test this hypothesis in a large population-based cohort study. Women born in Sweden 1958–2000 (N = 2,204,126) were identified and matched with the Medical Birth Register and the Cancer Register. The expected number of meningioma cases and risk ratios were calculated for parous and nulliparous women and compared to the observed number of cases. Compared to parous women, meningiomas were more common among nulliparous (SIR = 1.73; 95% CI 1.52–1.95). The number of meningioma cases detected during pregnancy was lower than the expected (SIR = 0.40; 95% CI 0.20–0.72). Moreover, no increased risk was found in the first-year post-partum (SIR = 1.04; 95% CI 0.74–1.41). Contrary to our hypothesis, there was no increased risk for diagnosing a meningioma during pregnancy or 1-year post-partum. A lower detection rate during pregnancy, may reflect under-utilization of diagnostic procedures, but the actual number of meningiomas was homogenously lower among parous than nulliparous women throughout the study period, indicating that pregnancy is not a risk factor for meningioma.

Fertility History and Cognitive Function in Late Life: The Case of Mexico

OBJECTIVES

Mexico is aging rapidly, which makes identification of life-course factors influencing cognition a public health priority. We evaluate how the number of children one has relates to cognition in Mexico, a rapidly aging country that experienced fertility declines across recent cohorts of older people.

METHOD

We analyze older adults (age 50+, n = 11,380) from the 2015 Mexican Health and Aging Study. Respondents were categorized by number of children ever born (0-1, 2-3, 4-5, 6+). Using ordinary least squares regression, we estimate independent associations between fertility history and cognition accounting for demographic, socioeconomic, health, and psychosocial factors.

RESULTS

We observed an inverse U-shaped relationship between number of children (peaking at 2-3 children) and cognitive function, regardless of gender. In regression analyses adjusted for confounding variables, having 0-1 (vs 2-3 children) was associated with poorer cognitive function only for females. Regardless of gender, having 6+ (vs 2-3 children) was associated with poorer cognitive function. These associations remained significant even after accounting for socioeconomic, health, employment, and psychosocial factors.

DISCUSSION

Our results suggest fertility history may play a role in late-life cognitive health and provide evidence that both low and high fertility may relate to poorer cognitive function. We discuss differences by gender.

Cross-Sectional Average Length of Life Childless

Increases in the average age at first birth and in the proportion of women remaining childless have extended the total number of years that women spend childless during their reproductive lifetime in several countries. To quantify the number of years that reproductive-age women live without children, we introduce the cross-sectional average length of life childless (CALC). This measure includes all the age-specific first-birth information available for the cohorts present at time t; it is a period measure based on cohort data. Using the Human Fertility Database, CALC is calculated for the year 2015 for all countries with long enough histories of fertility available. Results show that women in the majority of the studied countries spend, on average, more than half of their reproductive lives childless. Furthermore, the difference between CALCs in two countries can be decomposed to give a clear visualization of how each cohort contributes to the difference in the duration of the length of childless life in those populations. Our illustration of the decomposition shows that (1) in recent years, female cohorts in Japan and Spain at increasingly younger ages have been contributing to more years of childless life compared with those in Sweden, (2) the United States continues to represent an exception among the high-income countries with a low expectation for childless life of women, and (3) Hungary experienced a strong period effect of the recent Great Recession. These examples show that CALC and its decomposition can provide insights into first-birth patterns.

Number of parity/live birth(s) and cardiovascular disease among Iranian women and men: results of over 15 years of follow-up

Background

Most previous studies conducted in non-Middle Eastern populations have suggested that an increase in the number of parity/live birth(s) leads to cardiovascular disease (CVD) development, although their findings were inconclusive on this issue for both sexes. Biologic and socioeconomic pathways were suggested to explain this association. We studied this issue among urban Iranian men and women.

Methods

In this population-based cohort study, which included 3929 women and 2571 men aged ≥30 years, data for the number of parity/live birth(s) were obtained by a standard questionnaire. Participants were then annually followed for CVD events. Multivariable Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the number of parity/live birth(s) and other traditional CVD risk factors.

Results

During more than 15 years of follow-up, 456 and 524 CVD events have occurred among women and men, respectively. Among women, a J-shaped association was found between the number of live births and incident CVD with the lowest risk for women with two live births. Among women in multivariable analyses, each unit increase in parity had a HR of 1.05 (CI: 1.01–1.10), and having ≥4 parity was associated with a HR of 1.86 (0.97–3.56, p-value = 0.061). Among men, in comparison with participants who had 1 child, multivariable HRs of having 2, 3, and ≥ 4 children were 1.97 (1.24–3.12), 2.08 (1.31–3.31), and 2.08 (1.30–3.34), respectively.

Conclusion

To the best of our knowledge, the current study is the first report on this issue in the Middle East and North Africa region, a region with a high burden of CVD. It can now be suggested that the number of parity/live birth(s) is linked to CVD among the Iranian population, with this issue being more prominent among men. Further research is needed to support our results and clarify the pathways between the number of parity/live birth(s) and CVD development among Iranian populations by considering potential risk factors, especially psycho-socio-economic risk factors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-020-03499-2.

The Role of Fertility in the Demography of Grandparenthood: Evidence from Italy

Grandparents play an important role in their family’s lives. However, little is known about the demography of grandparenthood. Given dramatic recent changes in fertility, we explore the role of number of children and age at first birth in the timing of the transition into grandparenthood focusing on Italy, a country with well-known North-South fertility differentials. We used data from the 2009 Italian Survey ‘Family and Social Relations’ (N = 10,186) to estimate median ages of grandparenthood across three birth cohorts of parents (1920–29; 1930–39; 1940–49). Findings show an overall postponement of age of grandparenthood of 5 years, shifting for women from early to mid- or late-50s (in the South and North, respectively). Such postponement is largely driven by family compositional changes: although the age of grandparenthood among mothers of three or more children has not changed much over cohorts, the percentage of mothers with such characteristic decreased significantly. The heterogeneity in experiencing the transition to grandparenthood has implications for intergenerational transfers and other roles in later life.

Changing family structures and self-rated health of India's older population (1995-96 to 2014)

A common view within academia and Indian society is that older Indians are cared for by their families less than in the past. Children are a key source of support in later life and alternatives are limited, therefore declining fertility appears to corroborate this. However, the situation may be more complex. Having many children may be physiologically burdensome for women, sons and daughters have distinct care roles, social trends could affect support provision, and spouses also provide support. We assessed whether the changing structure of families has negatively affected health of the older population using three cross-sectional and nationally representative surveys of India's 60-plus population (1995-96, 2004 and 2014). We described changes in self-rated health and family structure (number of children, sons, and daughters, and marital status) and, using ordinal regression modelling, determined the association between family structure and self-rated health, stratified by survey year and gender. Our results indicate that family structure changes that occurred between 1995-96 and 2014 were largely associated with better health. Though family sizes declined, there were no health gains from having more than two children. In fact, having many children (particularly daughters) was associated with worse health for both men and women. There was some evidence that being sonless or childless was associated with worse health, but it remained rare to not have a son or child. Being currently married was associated with better health and became more common over the inter-survey period. Although our results suggest that demographic trends have not adversely affected health of the older population thus far, we propose that the largest changes in family structure are yet to come. The support available in coming years (and potential health impact) will rely on flexibility of the current system.

Association between Living with Children and the Health and Health Behavior of Women and Men. Are There Differences by Age? Results of the "German Health Update" (GEDA) Study

Does the health of women and men living with and without minor children differ, and are age differences evident in the association? For self-rated general health, depression, back pain, overweight, smoking and sporting inactivity, the GEDA data 2009-2012 (18-54 years, n = 39,096) were used to calculate prevalence for women and men stratified by parental status (living with children: yes/no) and age. Moreover, we calculated odds ratios and predictive margins, performing logistic regressions with interaction terms of parental status and age. Women and men aged 45-54 living with children are healthier than those not living with children. Parents aged 18-24 smoke more frequently and do less sport; young mothers are also more likely to be overweight and suffer from back pain than women not living with children. In multivariable analysis, the interaction of living with children and age is significant for all outcomes (except depression and back pain in men). Living with children is an important social determinant of health, highly dependent on age. It is to be discussed whether the bio-psycho-social situation has an influence on becoming a parent, or whether parenthood in different phases of life strains or enhances health.

Association of Childbearing With a Short-Term Reduced Risk of Crohn Disease in Mothers

Our aim in this study was to analyze the importance of childbearing for risk of inflammatory bowel disease. Using data from the Norwegian Population Register and the Norwegian Patient Register, we fitted discrete-time hazard models for diagnosis of Crohn disease (CD) or ulcerative colitis (UC) among men and women aged 18-81 years in 2011-2016. Year and various sociodemographic factors were controlled for. The data included 4,304 CD cases and 8,866 UC cases. Women whose youngest child was ≤4 years of age had lower CD risk the following year than childless women (odds ratio (OR) = 0.73, 95% confidence interval (CI): 0.62, 0.86). There was no such reduction in CD risk among fathers. Men whose youngest child was aged ≥20 years had higher risks of CD (OR = 1.22, 95% CI: 1.01, 1.49) and UC (OR = 1.15, 95% CI: 1.02, 1.30) than childless men. UC risk was also increased among men whose youngest child was aged ≤4 years (OR = 1.14, 95% CI: 1.02, 1.27). The short-term reduction in women's CD risk after a birth may reflect biological effects of pregnancy. Alternatively, it may reflect residual confounding or lifestyle effects of parenthood that are of special relevance for CD in women. In particular, differences in use of oral contraceptives (which it was not possible to control for) may have contributed to the observed pattern.

Men's age at first birth and alcohol-related morbidity and mortality among siblings

BACKGROUND

Men's age at first birth may negatively or positively affect alcohol-related morbidity and mortality, although little evidence is available.

METHODS

We used register data of over 22,000 brothers to analyze the associations between age at first birth and alcohol-related morbidity and mortality from the age of 35 until the age of 60 or 72. We employed conventional Cox models and inter-sibling models, which allowed adjustment for unobserved social and genetic characteristics shared by brothers.

RESULTS

The findings show that men's age at first birth was inversely associated with alcohol-related morbidity and mortality, independent of unobserved characteristics shared by brothers and of observed demographic confounders. Men who had their first child late at 35-45 years experienced lower alcohol-related morbidity and mortality (hazard ratio (HR) = 0.57, 95 % confidence interval (CI) = 0.43, 0.75) than men who had their first child at 25-29. Men who had their first child before age 20 had the highest morbidity and mortality among all fathers (HR = 1.36, 95 % CI = 1.09, 1.69), followed by men who had their child at 20-24 (HR = 1.12, 95 % CI = 1.00, 1.25).

CONCLUSIONS

The results imply that the inverse association between men's age at first birth and alcohol-related morbidity and mortality is not driven by familial characteristics.

Fertility History and Biomarkers Using Prospective Data: Evidence From the 1958 National Child Development Study

Research on the later-life health implications of fertility history has predominantly considered associations with mortality or self-reported indicators of health. Most of this previous research has either not been able to account for selection factors related to both early-life and later-life health or has had to rely on retrospectively reported accounts of childhood circumstances. Using the 1958 National Child Development Study, and in particular the biomedical survey conducted in 2002-2003, we investigate associations between fertility histories (number of children and age at first and at last birth) and biomarkers for cardiometabolic risk and respiratory function in midlife among both men and women. Results from models that adjusted for a very wide range of childhood factors, including early-life socioeconomic position, cognitive ability, and mental health, showed weak associations between parity and biomarkers. However, we found an inverse association between age at first birth and biomarkers indicative of worse cardiometabolic health, with poorer outcomes for those with very young ages at entry to parenthood and increasingly better outcomes for those becoming parents at older ages. A very young age at last birth was also associated with less favorable biomarker levels, especially among women. Results highlight the value of prospectively collected data and the availability of biomarkers in studies of life course determinants of health in midlife and later.

Infertility and mortality

BACKGROUND

Infertility affects 1 in 10 American reproductive-age women. The impact of this disease beyond the reproductive years is largely unknown.

OBJECTIVE

The objective of the study was to determine the association of infertility history with all-cause and cause-specific mortality.

STUDY DESIGN

This secondary analysis of a multicenter randomized clinical trial included 75,784 women (aged 55-74 years) prospectively enrolled in the Prostate, Lung, Colorectal, and Ovarian cancer-screening trial from 1992 through 2001 and followed up a minimum of 10 years for health-related outcomes and death (856,935 person-years). We examined the association of infertility history (inability to conceive for 1 year or greater) of all-cause and cause-specific mortality using disease risk score-adjusted Cox-proportional hazard regression models.

RESULTS

Infertile women had a 10% increased risk of death (from any cause) during the study period compared with the unexposed (adjusted hazard risk, 1.10, 95% confidence interval, 1.02-1.18, P = .010). This effect was predominantly noted in women at an otherwise low risk of mortality who had a 26% increased risk of death (adjusted hazard risk, 1.26, 95% confidence interval, 1.12-1.42, P < .001). No differences in cardiovascular or diabetic mortality were noted. The risk of cancer death at any time over the study period was increased by 23% in infertile women compared with the unexposed (adjusted hazard risk, 1.23, 95% confidence interval, 1.10-1.37, P < .001). This effect was predominantly noted in women at an otherwise low risk of cancer mortality who had a 47% increased risk of cancer death (adjusted hazard risk, 1.47, 95% confidence interval, 1.25-1.73, P < .001). While no differences are seen in the risk of death from endometrial or ovarian cancer, the risk of death from breast cancer was more than doubled in infertile women at an otherwise low risk of breast cancer death compared with the unexposed (adjusted hazard risk, 2.64, 95% confidence interval, 1.71-4.08, P < .001).

CONCLUSION

Infertility is a harbinger of future morbidity and mortality. Infertile women are at an increased risk of all-cause and cancer-related mortality. Consideration of infertility history in health care maintenance presents an opportunity for screening and early intervention for long-term health outcomes.

Is the Family Size of Parents and Children Still Related? Revisiting the Cross-Generational Relationship Over the Last Century

In most developed countries, the fertility levels of parents and children are positively correlated. This article analyzes the strength of the intergenerational transmission of family size over the last century, including a focus on this reproduction in large and small families. Using the large-scale French Family Survey (2011), we show a weak but significant correlation of approximately 0.12–0.15, which is comparable with levels in other Western countries. It is stronger for women than men, with a gender convergence across cohorts. A decrease in intergenerational transmission is observed across birth cohorts regardless of whether socioeconomic factors are controlled, supporting the idea that the family of origin has lost implicit and explicit influence on fertility choices. As parents were adopting the two-child family norm, the number of siblings lost its importance for having two children, but it continues to explain lower parity and, above all, three-child families. This suggests that the third child has increasingly become an “extra child” (beyond the norm) favored by people from large families.

Relationships Between Reproductive History and Mortality From Cardiovascular Diseases Among Japanese Women: The Japan Collaborative Cohort Study for Evaluation of Cancer Risk (JACC) Study

Background

Reproductive history has been addressed as a risk factor for cardiovascular disease (CVD). We examined the relationship between reproductive history and CVD mortality in Japanese women.

Methods

We followed 53,836 women without previous CVD or cancer history from 1988–1990 to 2009 in a prospective cohort study. Hazard ratios (HRs) and 95% confidence intervals (CIs) of CVD mortality were estimated according to the number of deliveries and maternal age at first delivery.

Results

During the follow-up, 2,982 CVD-related deaths were identified. There was U-shaped association between the number of deliveries and risk of CVD mortality with reference to three deliveries, although the excess risk of CVD mortality associated with ≥5 deliveries was of borderline statistical significance. The corresponding multivariable HRs were 1.33 (95% CI, 1.12–1.58) and 1.11 (95% CI, 0.99–1.24). In addition, higher CVD mortality was associated with maternal age ≥28 years at first delivery than maternal age of 24–27 years at first delivery. The multivariable HRs were 1.22 (95% CI, 1.10–1.36) for 28–31 years at first delivery and 1.26 (95% CI, 1.04–1.52) for ≥32 years at first delivery. Moreover, among women with ≥3 deliveries, maternal age ≥28 years at first delivery was associated with 1.2- to 1.5-fold increased CVD mortality.

Conclusion

The number of deliveries showed a U-shaped association with risk of CVD mortality. Higher maternal age at first delivery was associated with an increased risk of CVD mortality, and excessive risk in women aged ≥28 years at first delivery was noted in those with ≥3 deliveries.

Fertility trajectories and later-life depression among parents in England

We examine pathways between indicators of fertility tempo/quantum and depressive symptoms among parents aged 55+ with at least two children, using three waves of the English Longitudinal Study of Ageing. Using standard regression approaches and path analysis within the structural equation framework, we also investigate whether fertility trajectories mediated the association between childhood disadvantage and later-life depression. Results provide limited support for direct influences of fertility trajectories on depression, but indicate indirect linkages for both women and men. Associations are mediated by partnership history, social support, wealth, later-life smoking, and functional limitation. Associations between childhood disadvantage and later-life depression are partially mediated by fertility stressors. Results confirm the influence of life course experiences on depression at older ages and demonstrate the interlinked role of family and other life course pathways on later-life well-being.

Is the relationship between men's age at first birth and midlife health changing? Evidence from two British cohorts

Becoming a father, particularly for the first time, is a central transition in men's lives, and whether this transition takes place early or later in life may have important ramifications on the whole later life course. Previous research has shown that men who father their first child early in life have poorer later-life health than men who postpone having children. However, it is not known how selection by cognitive ability and other childhood characteristics confound the association between the timing of fatherhood and later-life health, or how the association is changing over time as parenthood is postponed to an older age. We investigate the association between men's age at the birth of their first child and midlife self-rated health in two British cohorts born in 1958 and 1970. The study employs logit models. Relative to men who had their first child when they were between 25 and 29 years old, men who had their first child before the age of 20 have the poorest health, followed by men who had a child when they were 20–24 years old. This result was observed in both cohorts. Childhood cognitive ability, which previous research has not analyzed, strongly contributed to this association, and to a greater extent than other childhood characteristics. For the 1970 cohort, those who became fathers at age 35 or older had the best health. This advantage was not found for the 1958 cohort. These findings suggest that the relationship between young age at fatherhood and midlife health is strongly confounded by cognitive ability, and that in recent cohorts a new pattern of advantage among older fathers has emerged.

•

Early fatherhood shows associations with poorer self-rated health in midlife.

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Childhood cognitive ability strongly confounds this association.

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First-time fathers aged 35 years or older have the best health in the 1970 cohort.

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A similar health advantage in older fathers is not found in the 1958 cohort.

The Intergenerational Transmission of Early Childbearing: Examining Direct and Indirect Associations in a Swedish Birth Cohort

Background. Research shows that early childbearing is associated negatively with educational attainment and socioeconomic status (SES). Children born to young versus older mothers often do less well in school, and many have early first births. Some studies suggest that mothers’ early childbearing operates through SES to influence the daughters’ early childbearing, and some argue that the association is strong net of SES. The current study tests these direct and indirect associations. Methods. We estimate the pathways through which mothers’ early childbearing influences daughters’ early childbearing in several steps. First, we examine bivariate associations between mothers’ early childbearing and SES, followed by bivariate associations between mothers’ SES outcomes and their daughters’ early childbearing. We then estimate the average marginal effects (AMEs) of mothers’ early children on daughters’, and a KHB decomposition to examine direct and indirect associations. Results. Findings suggest both direct and indirect associations. Nested models show that, net of a range of SES characteristics, mothers’ early childbearing increases the probability of daughters’ by approximately 8%; and KHB results suggest 37% mediation, with daughters’ school performance (12%) and household educational attainment (10%) contributing the highest shares. Conclusion. Mothers’ early childbearing and subsequent SES collectively influence the long-term wellbeing of children. Thus, early childbearing has consequences both within and across generations.

The role of children and their socioeconomic resources for the risk of hospitalisation and mortality - a nationwide register-based study of the total Swedish population over the age 70

Background

Previous studies have shown that mortality in old age is associated with both number of children and their socioeconomic resources. The underlying mechanisms are unclear, as well as when during the process of health deterioration the advantage of parents over non-parents arises. This study aims to examine how the number of children and their socioeconomic resources are associated with different health outcomes among their parents, namely the hazard for i) first hospitalisation, ii) re-admission, iii) mortality after first hospitalisation, and iv) overall mortality.

Method

This longitudinal cohort study includes all individuals born 1920–1940 who were living in Sweden at age 70 years (890,544 individuals). Individuals were linked to their offspring and spouse using administrative registers and followed for up to 25 years. Associations were estimated using multivariable Cox models adjusted for index persons’ education and income, marital status, their partners’ education, and age at first birth.

Results

In this study, having children was associated with reduced mortality risk of their parents, but not with the risk of being hospitalised, which increased as number of children increased. A higher education of children was protective for all parental outcomes independent of number of children and their financial resources. In fact, income of the children was only weakly associated with the health of their parents.

Conclusions

The benefit of having children compared to childlessness for health in old age seems to arise once individuals have become ill rather than before. Children’s education is important for parental health and mortality, in fact more important than the number of children itself in this Swedish cohort.

Electronic supplementary material

The online version of this article (10.1186/s12877-019-1134-y) contains supplementary material, which is available to authorized users.

Infertility: a marker of future health risk in women?

Infertility, may be a harbinger for future health risk in women, including early mortality. Fertility status itself could serve as an early biomarker, (present in a woman's reproductive years) for risk stratification later in life. The relationship between infertility and early mortality involves the impact of nulliparity on future adverse health events, potential sequelae from the underlying cause(s) of infertility, the risks of fertility treatments, as well as the potential for risk reduction from a healthy pregnancy. This complex interplay coupled with difficulties ascertaining infertility on a population level has presented unique challenges to assessing infertility and early mortality risk. With further study, a better understanding the role of fertility status in health at various stages of life may provide unique opportunities for surveillance and risk reduction.

Parity and Mortality: An Examination of Different Explanatory Mechanisms Using Data on Biological and Adoptive Parents

A growing literature has demonstrated a relationship between parity and mortality, but the explanation for that relationship remains unclear. This study aims to pick apart physiological and social explanations for the parity-mortality relationship by examining the mortality of parents who adopt children, but who have no biological children, in comparison with the mortality of parents with biological children. Using Swedish register data, we study post-reproductive mortality amongst women and men from cohorts born between 1915 and 1960, over ages 45-97. Our results show the relative risks of mortality for adoptive parents are always lower than those of parents with biological children. Mortality amongst adoptive parents is lower for those who adopt more than one child, while for parents with biological children we observe a U-shaped relationship, where parity-two parents have the lowest mortality. Our discussion considers the relative importance of physiological and social depletion effects, and selection processes.

Socioeconomic Position and Reproduction: Findings from the Australian Longitudinal Study on Women's Health

OBJECTIVE

To investigate the association of socioeconomic position (SEP) with reproductive outcomes among Australian women.

METHODS

Data from the Australian Longitudinal Study on Women's Health's (population-based cohort study) 1973-1978 cohort were used (N = 6899, aged 37-42 years in 2015). The association of SEP (childhood and own, multiple indicators) with age at first birth, birth-to-pregnancy (BTP) intervals and total number of children was analysed using multinomial logistic regression.

RESULTS

14% of women had their first birth aged < 24 years. 29% of multiparous women had a BTP interval within the WHO recommendation (18-27 months). Women with a low SEP had increased odds of a first birth < 24 years: low (OR 7.0: 95% C.I. 5.3, 9.3) or intermediate education (OR 3.8: 2.8, 5.1); living in rural (OR 1.8: 1.5, 2.2) or remote (OR 2.1: 1.7, 2.7) areas; who found it sometimes (OR 1.8: 1.5, 2.2) or always difficult (OR 2.0: 1.6, 2.7) to manage on their income; and did not know their parent's education (OR 4.5: 3.2, 6.4). Low SEP was associated with having a much longer than recommended BTP interval.

CONCLUSION

As the first Australian study describing social differences in reproductive characteristics, these findings provide a base for reducing social inequalities in reproduction. Assisting adequate BTP spacing is important, particularly for women with existing elevated risks due to social disadvantage; including having a first birth < 24 years of age and a longer than recommended BTP interval. This includes reviewing services/access to postnatal support, free family planning/contraception clinics, and improved family policies.

Fertility History and Physical and Mental Health Changes in European Older Adults

Previous studies have shown that aspects of reproductive history, such as earlier parenthood and high parity, are associated with poorer health in mid and later life. However, it is unclear which dimensions of health are most affected by reproductive history, and whether the pattern of associations varies for measures of physical, psychological and cognitive health. Such variation might provide more insight into possible underlying mechanisms. We use longitudinal data for men and women aged 50–79 years in ten European countries from the Survey of Health, Ageing and Retirement in Europe to analyse associations between completed fertility history and self-reported and observed health indicators measured 2–3 years apart (functional limitations, chronic diseases, grip strength, depression and cognition), adjusting for socio-demographic, and health factors at baseline. Using multiple imputation and pattern mixture modelling, we tested the robustness of estimates to missing data mechanisms. The results are partly consistent with previous studies and show that women who became mothers before age 20 had worse functional health at baseline and were more likely to suffer functional health declines. Parents of 4 or more children had worse physical, psychological and cognitive health at baseline and were more likely to develop circulatory disease over the follow-up period. Men who delayed fatherhood until age 35 or later had better health at baseline but did not experience significantly different health declines. This study improves our understanding of linkages between fertility histories and later life health and possible implications of changes in fertility patterns for population health. However, research ideally using prospective life course data is needed to further elucidate possible mechanisms, considering interactions with partnership histories, health behaviour patterns and socio-economic trajectories.

"Big data" in economic history

Big data is an exciting prospect for the field of economic history, which has long depended on the acquisition, keying, and cleaning of scarce numerical information about the past. This article examines two areas in which economic historians are already using big data - population and environment - discussing ways in which increased frequency of observation, denser samples, and smaller geographic units allow us to analyze the past with greater precision and often to track individuals, places, and phenomena across time. We also explore promising new sources of big data: organically created economic data, high resolution images, and textual corpora.

Reproductive period, endogenous estrogen exposure and dementia incidence among women in Latin America and China; A 10/66 population-based cohort study

BACKGROUND

Exposure to endogenous estrogen may protect against dementia, but evidence remains equivocal. Such effects may be assessed more precisely in settings where exogenous estrogen administration is rare. We aimed to determine whether reproductive period (menarche to menopause), and other indicators of endogenous estrogen exposure are inversely associated with dementia incidence.

METHODS

Population-based cohort studies of women aged 65 years and over in urban sites in Cuba, Dominican Republic, Puerto Rico and Venezuela, and rural and urban sites in Peru, Mexico and China. Sociodemographic and risk factor questionnaires were administered to all participants, including ages at menarche, birth of first child, and menopause, and parity, with ascertainment of incident 10/66 dementia, and mortality, three to five years later.

RESULTS

9,428 women participated at baseline, with 72-98% responding by site. The 'at risk' cohort comprised 8,466 dementia-free women. Mean age varied from 72.0 to 75.4 years, lower in rural than urban sites and in China than in Latin America. Mean parity was 4.1 (2.4-7.2 by site), generally higher in rural than urban sites. 6,854 women with baseline reproductive period data were followed up for 26,463 person years. There were 692 cases of incident dementia, and 895 dementia free deaths. Pooled meta-analysed fixed effects, per year, for reproductive period (Adjusted Sub-Hazard Ratio [ASHR] 1.001, 95% CI 0.988-1.015) did not support any association with dementia incidence, with no evidence for effect modification by APOE genotype. No association was observed between incident dementia and; ages at menarche, birth of first child, and menopause: nulliparity; or index of cumulative endogenous estrogen exposure. Greater parity was positively associated with incident dementia (ASHR 1.030, 95% CI 1.002-1.059, I2 = 0.0%).

CONCLUSIONS

We found no evidence to support the theory that natural variation in cumulative exposure to endogenous oestrogens across the reproductive period influences dementia incidence in late life.