Time-to-pregnancy and risk of cardiovascular disease among men and women

Association between Life's Essential 8 and Infertility as Well as the Mediating Effects of Oxidative Stress and Inflammatory Factors Among U.S. Women Aged 18-45 Years

Management of cardiovascular disease in pregnancy is important, yet the association between cardiovascular health and infertility is rarely reported. In this study, we aimed to explore the association between Life's Essential 8 (LE8), a novel cardiovascular health (CVH) measure, and infertility, and to investigate potential mediating mechanisms. This study investigated cross-sectional data from the 2013-2018 National Health and Nutrition Examination Survey. LE8 score (ranging from 0 to 100) was calculated as the unweighted average of eight CVH metrics. The association between LE8 and infertility was explored through weighted multiple logistic regression. Restricted cubic splines were used to explore nonlinear correlation. In addition, mediation analysis was conducted to investigate the role of oxidative stress and inflammatory markers systematically. After strict exclusion criteria, 1703 American women aged 18-45 years were included. After full adjustment, the LE8 score showed a negative correlation with infertility [per 1 SD increase, OR = 0.675, 95% CI: 0.553-0.824], with a linear dose-response relationship (non-linear P = 0.122). Similar linear negative correlations were found between health factor scores and infertility, with higher body mass index and glucose scores having a significantly lower risk of infertility. Stratified analyses showed a stronger inversed relationship between LE8 and infertility in younger populations. Moreover, mediation analysis revealed that uric acid concentration and lymphocyte count mediated the effect of LE8 on infertility (P < 0.05). LE8 and its subscale scores were linearly and negatively associated with infertility, which may be mediated in part through uric acid and lymphocyte count. Focusing on weight management and glycemic control can effectively reduce the risk of infertility.

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.

Cardiovascular disease risk factors and infertility: multivariable analyses and one-sample Mendelian randomization analyses in the Trøndelag Health Study

STUDY QUESTION

Are cardiovascular disease (CVD) risk factors causally associated with higher risk of infertility among women and men?

SUMMARY ANSWER

We found evidence to support a causal relationship between smoking initiation and history of infertility in women.

WHAT IS KNOWN ALREADY

Several CVD risk factors are associated with history of infertility. Previous studies using Mendelian randomization (MR) further support a causal relationship between BMI and infertility in women.

STUDY DESIGN SIZE DURATION

We used data from the Trøndelag Health Study (HUNT) in Norway, a prospective population-based cohort study, including 26 811 women and 15 598 men participating in three survey collections in 1995-1997 (HUNT2), 2006-2008 (HUNT3), and 2017-2019 (HUNT4).

PARTICIPANTS/MATERIALS SETTING METHODS

Our outcome was women's self-reported history of infertility, defined as ever having tried to conceive for 12 months or more or having used ART. We assigned the history of infertility reported by women to their male partners; therefore, the measure of infertility was on the couple level. We used both conventional multivariable analyses and one-sample MR analyses to evaluate the association between female and male CVD risk factors (including BMI, blood pressure, lipid profile measurements, and smoking behaviours) and history of infertility in women and men, separately.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 4702 women (18%) and 2508 men (16%) were classified with a history of infertility. We found a higher risk of infertility among female smokers compared to non-smokers in both multivariable and MR analyses (odds ratio (OR) in multivariable analysis, 1.20; 95% CI, 1.12-1.28; OR in MR analysis, 1.13; CI, 1.02-1.26), and potentially for higher BMI (OR in multivariable analysis, 1.13; CI, 1.09-1.18; OR in MR analysis, 1.11, CI, 0.92-1.34). In multivariable analysis in women, we also found evidence of associations between triglyceride levels, high-density lipoprotein cholesterol, lifetime smoking index, and smoking intensity with higher risk of infertility. However, these results were not consistent in MR analyses. We found no robust or consistent associations between male CVD risk factors and infertility.

LIMITATIONS REASONS FOR CAUTION

Our main limitation was that the CVD risk factors measured might not adequately capture the relevant time periods for when couples were trying to conceive. Additionally, we did not have information on causes of infertility in either women or men.

WIDER IMPLICATIONS OF THE FINDINGS

Women with infertility could have a worse CVD risk factor profile and thus public health interventions aimed at reducing the impact of some CVD risk factors, such as smoking and BMI, could reduce the burden of infertility. However, additional MR studies of the relationship between CVD risk factors and infertility with a larger sample size would be of value.

STUDY FUNDING/COMPETING INTERESTS

The study was supported by a grant from the European Research Council under the European Union's Horizon 2020 research and innovation program (grant agreements no. 947684). This research was also supported by the Research Council of Norway through its Centres of Excellence funding scheme (project no. 262700) and partly funded by the Research Council of Norway, project: Women's fertility-an essential component of health and well-being (project no. 320656). D.A.L. and A.F. work in a unit that is supported by the University of Bristol and the UK Medical Research Council (MC_UU_00011/6). D.A.L.'s contribution to the article is supported by the European Research Council (101021566), the British Heart Foundation (CH/F/20/90003 and AA/18/7/34219). S.B.'s contribution to the article is supported by the Wellcome Trust (225790/Z/22/Z). B.M.B. is funded by The Liaison Committee for education, research and innovation in Central Norway; and the Joint Research Committee between St. Olavs Hospital and the Faculty of Medicine and Health Sciences, NTNU. The genotyping in HUNT was financed by the National Institute of Health (NIH); University of Michigan; The Research Council of Norway; The Liaison Committee for education, research and innovation in Central Norway; and the Joint Research Committee between St. Olavs Hospital and the Faculty of Medicine and Health Sciences, NTNU. None of the funding organizations influenced the study design, reporting, or interpretation of results. The views expressed in the present article are those of the authors and not necessarily any acknowledged funding organization. D.A.L. reports grants from Medtronic Ltd and Roche Diagnostics outside the submitted work. The other authors have no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Parental infertility and offspring cardiometabolic trajectories: a pooled analysis of three European cohorts

OBJECTIVE

To assess whether parental infertility is associated with differences in cardiometabolic trajectories in offspring.

DESIGN

Pooled observational analysis in three prospective cohorts.

SETTING

Three nationwide pregnancy cohorts.

PATIENTS

A total of 14,609 singletons from the UK Avon Longitudinal Study of Parents and Children, the Portuguese Geraçao 21, and the Amsterdam Born Children and Their Development study. Each cohort contributed data up to ages 26, 12, and 13 years, respectively.

INTERVENTION

Parental infertility is defined as time-to-pregnancy of ≥12 months (n = 1,392, 9.5%).

MAIN OUTCOME MEASURES

Trajectories of body mass index (BMI), waist circumference, systolic blood pressure, diastolic blood pressure, low-density lipoprotein cholesterol (LDL-C) level, high-density lipoprotein cholesterol (HDL-C) level, triglycerides level, and glucose level were compared in the offspring of couples with and without infertility. Trajectories were modeled using mixed-effects models with natural cubic splines adjusting for cohort, sex of the offspring, and maternal factors (age, BMI, smoking, educational level, parity, and ethnicity). Predicted levels of cardiometabolic traits up to 25 years of age were compared with parental infertility.

RESULTS

Offspring of couples with infertility had increasingly higher BMI (difference in mean predicted levels by age 25 years: 1.09 kg/m2, 95% confidence interval [0.68-1.50]) and suggestively higher diastolic blood pressure at age 25 years (1.21 mmHg [-0.003 to 2.43]). Their LDL-C tended to be higher, and their HDL-C values tended to be lower over time (age: 25 years, LDL-C: 4.07% [-0.79 to 8.93]; HDL-C: -2.78% [-6.99 to 1.43]). At age 17 years, offspring of couples with infertility had higher waist circumference (1.05 cm [0.11-1.99]) and systolic blood pressure (age: 17 years; 0.93 mmHg [0.044-1.81]), but these differences attenuated at later ages. No intergroup differences in triglyceride and glucose level trajectories were observed. Further adjustment for paternal age, BMI, smoking, and educational level, and both parents' histories of diabetes and hypertension in the cohort with this information available (Avon Longitudinal Study of Parents and Children) did not attenuate intergroup differences.

CONCLUSION

Offspring of couples with infertility relative to those of fertile couples have increasingly higher BMI over the years, suggestively higher blood pressure levels, and tend to have greater values of LDL-C and lower values of HDL-C with age.

Pregnancy History at 40 Years of Age as a Marker of Cardiovascular Risk

BACKGROUND

Individual pregnancy complications are associated with increased maternal risk of cardiovascular disease. We assessed the link between a woman's total pregnancy history at 40 years of age and her relative risk of dying from atherosclerotic cardiovascular disease (ASCVD).

METHODS AND RESULTS

This population-based prospective study combined several Norwegian registries covering the period 1967 to 2020. We identified 854 442 women born after 1944 or registered with a pregnancy in 1967 or later, and surviving to 40 years of age. The main outcome was the time to ASCVD mortality through age 69 years. The exposure was a woman's number of recorded pregnancies (0, 1, 2, 3, or 4) and the number of those with complications (preterm delivery <35 gestational weeks, preeclampsia, placental abruption, perinatal death, and term or near-term birth weight <2700 g). Cox models provided estimates of hazard ratios across exposure categories. The group with the lowest ASCVD mortality was that with 3 pregnancies and no complications, which served as the reference group. Among women reaching 40 years of age, risk of ASCVD mortality through 69 years of age increased with the number of complicated pregnancies in a strong dose-response fashion, reaching 23-fold increased risk (95% CI, 10-51) for women with 4 complicated pregnancies. Based on pregnancy history alone, 19% of women at 40 years of age (including nulliparous women) had an increased ASCVD mortality risk in the range of 2.5- to 5-fold.

CONCLUSIONS

Pregnancy history at 40 years of age is strongly associated with ASCVD mortality. Further research should explore how much pregnancy history at 40 years of age adds to established cardiovascular disease risk factors in predicting cardiovascular disease mortality.

Time to pregnancy and life expectancy: a cohort study of 18 796 pregnant couples

STUDY QUESTION

Is fecundity, measured as time to pregnancy (TTP), associated with mortality in parents?

SUMMARY ANSWER

Prolonged TTP is associated with increased mortality in both mothers and fathers in a dose-response manner.

WHAT IS KNOWN ALREADY

Several studies have linked both male and female fecundity to mortality. In women, infertility has been linked to several diseases, but studies suggest that the underlying conditions, rather than infertility, increase mortality.

STUDY DESIGN, SIZE, DURATION

A prospective cohort study was carried out on 18 796 pregnant couples, in which the pregnant women attended prophylactic antenatal care between 1973 and 1987 at a primary and tertiary care unit. The couples were followed in Danish mortality registers from their child's birth date until death or until 2018. The follow-up period was up to 47 years, and there was complete follow-up until death, emigration or end of study.

PARTICIPANTS/MATERIALS, SETTING, METHODS

At the first antenatal visit, the pregnant women were asked to report the time to the current pregnancy. Inclusion was restricted to the first pregnancy, and TTP was categorised into <12 months, ≥12 months, not planned, and not available. In sub-analyses, TTP ≥12 was further categorized into 12-35, 36-60, and >60 months. Information for parents was linked to several Danish nationwide health registries. Survival analysis was used to estimate the hazard ratios (HRs) with a 95% CI for survival and adjusted for age at the first attempt to become pregnant, year of birth, socioeconomic status, mother's smoking during pregnancy, and mother's BMI.

MAIN RESULTS AND THE ROLE OF CHANCE

Mothers and fathers with TTP >60 months survived, respectively, 3.5 (95% CI: 2.6-4.3) and 2.7 (95% CI: 1.8-3.7) years shorter than parents with a TTP <12 months. The mortality was higher for fathers (HR: 1.21, 95% CI: 1.09-1.34) and mothers (HR: 1.29, 95% CI: 1.12-1.49) with TTP ≥12 months compared to parents with TTP <12 months. The risk of all-cause mortality during the study period increased in a dose-response manner with the highest adjusted HR of 1.98 (95% CI: 1.62-2.41) for fathers and 2.03 (95% CI: 1.56-2.63) for mothers with TTP >60 months. Prolonged TTP was associated with several different causes of death in both fathers and mothers, indicating that the underlying causes of the relation between fecundity and survival may be multi-factorial.

LIMITATIONS, REASONS FOR CAUTION

A limitation is that fecundity is measured using a pregnancy-based approach. Thus, the cohort is conditioned on fertility success and excludes sterile couples, unsuccessful attempts and spontaneous abortions. The question used to measure TTP when the pregnant woman was interviewed at her first attended prophylactic antenatal care: 'From the time you wanted a pregnancy until it occurred, how much time passed?' could potentially have led to serious misclassification if the woman did not answer on time starting unprotected intercourse but on the start of wishing to have a child.

WIDER IMPLICATIONS OF THE FINDINGS

We found that TTP is a strong marker of survival, contributing to the still-emerging evidence that fecundity in men and women reflects their health and survival potential.

STUDY FUNDING/COMPETING INTEREST(S)

The authors acknowledge an unrestricted grant from Ferring. The funder was not involved in the study design, collection, analysis, interpretation of data, the writing of this article, or the decision to submit it for publication. M.L.E. is an advisor to Ro, VSeat, Doveras, and Next.

TRIAL REGISTRATION NUMBER

N/A.

Update on sex specific risk factors in cardiovascular disease

Cardiovascular disease (CVD) is the leading cause of death worldwide and accounts for roughly 1 in 5 deaths in the United States. Women in particular face significant disparities in their cardiovascular care when compared to men, both in the diagnosis and treatment of CVD. Sex differences exist in the prevalence and effect of cardiovascular risk factors. For example, women with history of traditional cardiovascular risk factors including hypertension, tobacco use, and diabetes carry a higher risk of major cardiovascular events and mortality when compared to men. These discrepancies in terms of the relative risk of CVD when traditional risk factors are present appear to explain some, but not all, of the observed differences among men and women. Sex-specific cardiovascular disease research-from identification, risk stratification, and treatment-has received increasing recognition in recent years, highlighting the current underestimated association between CVD and a woman's obstetric and reproductive history. In this comprehensive review, sex-specific risk factors unique to women including adverse pregnancy outcomes (APO), such as hypertensive disorders of pregnancy (HDP), gestational diabetes mellitus, preterm delivery, and newborn size for gestational age, as well as premature menarche, menopause and vasomotor symptoms, polycystic ovarian syndrome (PCOS), and infertility will be discussed in full detail and their association with CVD risk. Additional entities including spontaneous coronary artery dissection (SCAD), coronary microvascular disease (CMD), systemic autoimmune disorders, and mental and behavioral health will also be discussed in terms of their prevalence among women and their association with CVD. In this comprehensive review, we will also provide clinicians with a guide to address current knowledge gaps including implementation of a sex-specific patient questionnaire to allow for appropriate risk assessment, stratification, and prevention of CVD in women.

History of Infertility and Midlife Cardiovascular Health in Female Individuals

Importance

Fertility status is a marker for future health, and infertility has been associated with risk for later cancer and diabetes, but associations with midlife cardiovascular health (CVH) in female individuals remain understudied.

Objective

To evaluate the association of infertility history with CVH at midlife (approximately age 50 years) among parous individuals.

Design, Setting, and Participants

Project Viva is a prospective cohort study of pregnant participants enrolled between 1999 and 2002 who delivered a singleton live birth in the greater Boston, Massachusetts, area. Infertility history was collected at a midlife visit between 2017 and 2021, approximately 18 years after enrollment. Data analysis was performed from January to June 2023.

Exposures

The primary exposure was any lifetime history of infertility identified by self-report, medical record, diagnosis, or claims for infertility treatment.

Main Outcomes and Measures

The American Heart Association's Life's Essential 8 (LE8) is a construct for ranking CVH that includes scores from 0 to 100 (higher scores denote better health status) in 4 behavioral (diet, physical activity, sleep, and smoking status) and 4 biomedical (body mass index, blood pressure, blood lipids, and glycemia) domains to form an overall assessment of CVH. Associations of a history of infertility (yes or no) with mean LE8 total, behavioral, biomedical, and blood biomarker (lipids and glycemia) scores were examined, adjusting for age at outcome (midlife visit), race and ethnicity, education, household income, age at menarche, and perceived body size at age 10 years.

Results

Of 468 included participants (mean [SD] age at the midlife visit, 50.6 [5.3] years) with exposure and outcome data, 160 (34.2%) experienced any infertility. Mean (SD) LE8 scores were 76.3 (12.2) overall, 76.5 (13.4) for the behavioral domain, 76.0 (17.5) for the biomedical domain, and 78.9 (19.2) for the blood biomarkers subdomain. In adjusted models, the estimated overall LE8 score at midlife was 2.94 points lower (95% CI, -5.13 to -0.74 points), the biomedical score was 4.07 points lower (95% CI, -7.33 to -0.78 points), and the blood subdomain score was 5.98 points lower (95% CI, -9.71 to -2.26 points) among those with vs without history of infertility. The point estimate also was lower for the behavioral domain score (β = -1.81; 95% CI, -4.28 to 0.66), although the result was not statistically significant.

Conclusions and Relevance

This cohort study of parous individuals found evidence for an association between a history of infertility and lower overall and biomedical CVH scores. Future study of enhanced cardiovascular preventive strategies among those who experience infertility is warranted.

miR-484 mediates oxidative stress-induced ovarian dysfunction and promotes granulosa cell apoptosis via SESN2 downregulation

Ovarian dysfunction is a common cause of female infertility, which is associated with genetic, autoimmune and environmental factors. Granulosa cells (GCs) constitute the largest cell population of ovarian follicles. Changes in GCs, including oxidative stress (OS) and excessive reactive oxygen species (ROS), are involved in regulating ovary function. miR-484 is highly expressed in 3-NP-induced oxidative stress models of ovaries and GCs. miR-484 overexpression aggravated GCs dysfunction and thereby intensified ovarian oxidative stress injury in mice. Moreover, bioinformatic analyses, luciferase assays and pull-down assays indicated that LINC00958 acted as a competing endogenous RNA (ceRNA) for miR-484 and formed a signaling axis with Sestrin2(SESN2) under oxidative stress conditions, which in turn regulated mitochondrial functions and mitochondrial-related apoptosis in GCs. Additionally, the inhibition of miR-484 alleviated GCs dysfunction under ovarian oxidative stress condition. Our present study revealed the role of miR-484 in oxidative stress of ovaries and GCs and the function of LINC00958/miR-484/SESN2 axis in mitochondrial function and mitochondria-related apoptosis.

Long-term cardiometabolic health in people born after assisted reproductive technology: a multi-cohort analysis

AIMS

To examine associations of assisted reproductive technology (ART) conception (vs. natural conception: NC) with offspring cardiometabolic health outcomes and whether these differ with age.

METHODS AND RESULTS

Differences in systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR), lipids, and hyperglycaemic/insulin resistance markers were examined using multiple linear regression models in 14 population-based birth cohorts in Europe, Australia, and Singapore, and results were combined using meta-analysis. Change in cardiometabolic outcomes from 2 to 26 years was examined using trajectory modelling of four cohorts with repeated measures. 35 938 (654 ART) offspring were included in the meta-analysis. Mean age ranged from 13 months to 27.4 years but was <10 years in 11/14 cohorts. Meta-analysis found no statistical difference (ART minus NC) in SBP (-0.53 mmHg; 95% CI:-1.59 to 0.53), DBP (-0.24 mmHg; -0.83 to 0.35), or HR (0.02 beat/min; -0.91 to 0.94). Total cholesterol (2.59%; 0.10-5.07), HDL cholesterol (4.16%; 2.52-5.81), LDL cholesterol (4.95%; 0.47-9.43) were statistically significantly higher in ART-conceived vs. NC offspring. No statistical difference was seen for triglycerides (TG), glucose, insulin, and glycated haemoglobin. Long-term follow-up of 17 244 (244 ART) births identified statistically significant associations between ART and lower predicted SBP/DBP in childhood, and subtle trajectories to higher SBP and TG in young adulthood; however, most differences were not statistically significant.

CONCLUSION

These findings of small and statistically non-significant differences in offspring cardiometabolic outcomes should reassure people receiving ART. Longer-term follow-up is warranted to investigate changes over adulthood in the risks of hypertension, dyslipidaemia, and preclinical and clinical cardiovascular disease.

Infertility and Risk of Cardiovascular Disease: A Prospective Cohort Study

Background Certain symptoms associated with infertility are associated with cardiovascular disease, including menstrual cycle irregularity, early menopause, and obesity; however, few studies have investigated the association between infertility and cardiovascular disease risk. Methods and Results Participants in the NHSII (Nurses' Health Study II) who reported infertility (12 months of trying to conceive without success, including women who subsequently conceived) or who were gravid, with no infertility were followed from 1989 until 2017 for development of incident, physician-diagnosed coronary heart disease (CHD) (myocardial infarction, coronary artery bypass grafting, angioplasty, stent) and stroke. Time-varying Cox proportional hazard models were used to calculate hazard ratios (HRs) and 95% CIs and were adjusted a priori for potential confounding variables. Among 103 729 participants, 27.6% reported having ever experienced infertility. Compared with gravid women who had not reported infertility, women with a history of infertility had greater risk of CHD (HR, 1.13 [95% CI, 1.01-1.26]) but not stroke (HR, 0.91 [95% CI, 0.77-1.07]). The association between history of infertility and CHD was strongest among women who reported infertility at an earlier age (HR for infertility first reported at ≤25 years, 1.26 [95% CI, 1.09-1.46]; HR at 26-30 years, 1.08 [95% CI, 0.93-1.25]; HR at >30 years, 0.91 [95% CI, 0.70-1.19]). When we investigated specific infertility diagnoses, elevated risk of CHD was observed among women whose infertility was attributed to an ovulatory disorder (HR, 1.28 [95% CI, 1.05-1.55]) or endometriosis (HR, 1.42 [95% CI, 1.09-1.85]). Conclusions Women with infertility may be at an increased risk of CHD. Risk differed by age at first infertility diagnosis and was restricted to ovulatory- and endometriosis-related infertility.

Approaches for Assessing Effects of Exposures on Human Fertility

BACKGROUND

Fecundability (conception rate per menstrual cycle) varies among non-contracepting couples. Time-to-pregnancy studies can identify exposures contributing to that variability, using three designs: incident cohort, prevalent cohort, and retrospective. Typically, researchers then apply semi-parametric, generalized linear time-to-pregnancy models to data, with either a log or a logit "link," to estimate either a fecundability ratio (FR) or a fecundability odds ratio (FOR). The ongoing-attempt study design can also be informative.

METHODS

We consider a different generalized linear model, based on an inverse link. It models the heterogeneity as beta distributed and enables estimation of both the FR and FOR, defined based on population mean fecundabilities, without requiring constancy across attempt time. Under an ongoing-attempt design, the parameter associated with a dichotomous exposure has no clear meaning with a log or a logit link, but under the proposed approach estimates the ratio of the two average times to pregnancy. Basing simulations on conception rates from a large study, we compare the three analytic approaches for confidence interval coverage and power. We also assess the performance of a commonly used method for verifying the constancy of FOR or FR across time.

RESULTS

The inverse-link approach had slightly less power than the others, but its estimates maintained nominal confidence interval coverage under nonconstancy. A popular method for testing constancy across time for the FR and FOR had poor power.

CONCLUSIONS

The inverse-link analysis offers a useful alternative to the usual methods, with estimation performance that generalizes to the ongoing-attempt design and does not require hard-to-verify constancy assumptions.

Risk of cardiovascular disease in women and men with subfertility: the Trøndelag Health Study

OBJECTIVE

To investigate the association between subfertility and risk of cardiovascular disease (CVD) outcomes.

DESIGN

Prospective study.

SETTING

Population-based cohort.

PATIENT(S)

We studied 31,629 women and 17,630 men participating in the Trøndelag Health Study.

INTERVENTION(S)

Self-reported subfertility. As men were not directly asked about fertility, male partners of female participants were identified through linkage to the Medical Birth Registry of Norway and assigned the fertility information obtained from their partners.

MAIN OUTCOME MEASURE(S)

The primary outcomes were stroke and coronary heart disease in women and men with and without a history of subfertility. The secondary outcomes were myocardial infarction and angina (subgroups of coronary heart disease) and any CVD (stroke or coronary heart disease). Information on CVD was available by linkage to hospital records. We used Cox proportional hazards models adjusted for age at participation in the Trøndelag Health Study (linear + squared), birth year, smoking history, cohabitation, and education. Cardiometabolic factors were assessed in separate models.

RESULT(S)

A total of 17% of women and 15% of men reported subfertility. In women, subfertility was modestly associated with an increased risk of stroke (age-adjusted hazard ratio [aaHR], 1.19; 95% confidence interval [CI], 1.02-1.39; adjusted hazard ratio [aHR]; 1.18; 95% CI, 1.01-1.37) and coronary heart disease (aaHR, 1.19; 95% CI, 1.06-1.33; aHR, 1.16; 95% CI, 1.03-1.30) compared with fertile women. In men, we observed a weak positive association for stroke (aaHR, 1.11; 95% CI, 0.91-1.34; aHR, 1.10; 95% CI, 0.91-1.33) and a weak inverse association for coronary heart disease (aaHR, 0.92; 95% CI, 0.81-1.05; aHR, 0.93; 95% CI, 0.81-1.06).

CONCLUSION(S)

We observed modestly increased risks of CVD outcomes in women and some weak associations in men, although with no strong statistical evidence on sex differences. We acknowledge that we were only able to include men linked to pregnancies ending at 12 completed gestational weeks or later, potentially resulting in selection bias and misclassification of history of subfertility in analyses of male partners. Despite the large sample size, our results indicate the need for larger studies to obtain precise results in both sexes and determine whether there are true sex differences.

Menopause: a cardiometabolic transition

Menopause is often a turning point for women's health worldwide. Increasing knowledge from experimental data and clinical studies indicates that cardiometabolic changes can manifest at the menopausal transition, superimposing the effect of ageing onto the risk of cardiovascular disease. The menopausal transition is associated with an increase in fat mass (predominantly in the truncal region), an increase in insulin resistance, dyslipidaemia, and endothelial dysfunction. Exposure to endogenous oestrogen during the reproductive years provides women with protection against cardiovascular disease, which is lost around 10 years after the onset of menopause. In particular, women with vasomotor symptoms during menopause seem to have an unfavourable cardiometabolic profile. Early management of the traditional risk factors of cardiovascular disease (ie, hypertension, obesity, diabetes, dyslipidaemia, and smoking) is essential; however, it is important to recognise in the reproductive history the female-specific conditions (ie, gestational hypertension or diabetes, premature ovarian insufficiency, some gynaecological diseases such as functional hypothalamic amenorrhoea, and probably others) that could enhance the risk of cardiovascular disease during and after the menopausal transition. In this Review, the first of a Series of two papers, we provide an overview of the literature for understanding cardiometabolic changes and the management of women at midlife (40-65 years) who are at higher risk, focusing on the identification of factors that can predict the occurrence of cardiovascular disease. We also summarise evidence about preventive non-hormonal strategies in the context of cardiometabolic health.

Metabolic health status and fecundability in a Singapore preconception cohort study

BACKGROUND

Obesity compromises metabolic health and female fertility, yet not all obese women are similar in metabolic status. The extent to which fecundability is influenced by the metabolic health status of women who are overweight or obese before conception is unknown.

OBJECTIVE

This study aimed to: (1) determine the metabolic health status, and (2) examine the association between metabolic health status and fecundability of overweight and obese women trying to conceive in the Singapore PREconception Study of long-Term maternal and child Outcomes cohort study.

STUDY DESIGN

We conducted a prospective preconception cohort study of Asian women (Chinese, Malay, and Indian) aged 18 to 45 years trying to conceive who were treated from 2015 to 2017 in KK Women's and Children's Hospital in Singapore (n=834). We defined women to have metabolically unhealthy status if they: (1) met 3 or more modified Joint Interim Statement metabolic syndrome criteria; or (2) had homeostasis model assessment-insulin resistance index ≥2.5. Body mass index was categorized as normal (18.5-22.9 kg/m2), overweight (23-27.4 kg/m2), or obese (≥27.5 kg/m2) on the basis of cutoff points for Asian populations. Fecundability was measured by time to pregnancy in menstrual cycles within a year of enrolment. Discrete-time proportional hazards models were used to estimate fecundability odds ratios, with adjustment for confounders and accounting for left truncation and right censoring.

RESULTS

Of 232 overweight women, 28 (12.1%) and 25 (10.8%) were metabolically unhealthy by metabolic syndrome ≥3 criteria and homeostasis model assessment-insulin resistance ≥2.5, respectively. Of 175 obese women, 54 (30.9%) and 93 (53.1%) were metabolically unhealthy by metabolic syndrome ≥3 criteria and homeostasis model assessment-insulin resistance ≥2.5, respectively. Compared with metabolically healthy normal-weight women, lower fecundability was observed in metabolically unhealthy overweight women on the basis of metabolic syndrome criteria (fecundability odds ratios, 0.38 [95% confidence interval, 0.15-0.92]) and homeostasis model assessment-insulin resistance (fecundability odds ratios, 0.68 [95% confidence interval, 0.33-1.39]), with metabolic syndrome criteria showing a stronger association. Metabolically unhealthy obese women showed lower fecundability than the healthy normal-weight reference group by both metabolic syndrome (fecundability odds ratios, 0.35; 95% confidence interval, 0.17-0.72) and homeostasis model assessment-insulin resistance criteria (fecundability odds ratios, 0.43; 95% confidence interval, 0.26-0.71). Reduced fecundability was not observed in overweight or obese women who showed healthy metabolic profiles by either definition.

CONCLUSION

Overweight or obesity was not synonymous with having metabolic syndrome or insulin resistance. In our preconception cohort, metabolically unhealthy overweight and obese women showed reduced fecundability, unlike their counterparts who were metabolically healthy. These findings suggest that metabolic health status, rather than simply being overweight and obese per se, plays an important role in fecundability.

Association of infertility with atherosclerotic cardiovascular disease among postmenopausal participants in the Women’s Health Initiative

OBJECTIVE

To investigate the association of infertility with atherosclerotic cardiovascular disease (ASCVD) among postmenopausal participants in the Women's Health Initiative (WHI). We hypothesized that nulliparity and pregnancy loss may reveal more extreme phenotypes of infertility, enabling further understanding of the association of infertility with ASCVD.

DESIGN

Prospective cohort study.

SETTING

Forty clinical centers in the United States.

PATIENT(S)

A total of 158,787 postmenopausal participants in the Women's Health Initiative cohort.

INTERVENTION(S)

Infertility, parity, and pregnancy loss.

MAIN OUTCOME MEASURE(S)

The primary outcome was risk of ASCVD among women with and without a history of infertility, stratified by history of live birth and pregnancy loss. Cox proportional-hazards models were adjusted for demographics and risk factors for ASCVD.

RESULT(S)

Among 158,787 women, 25,933 (16.3%) reported a history of infertility; 20,427 (80%) had at least 1 live birth; and 9,062 (35%) had at least 1 pregnancy loss. There was a moderate overall association between infertility and ASCVD (adjusted hazard ratio, 1.02; 95% confidence interval [CI], 0.99-1.06) over 19 years of follow-up. Among nulliparous women, infertility was associated with a 13% higher risk of ASCVD (95% CI, 1.04-1.23). Among nulliparous women who had a pregnancy loss, infertility was associated with a 36% higher risk of ASCVD (95% CI, 1.09-1.71).

CONCLUSION(S)

Women with a history of infertility overall had a moderately higher risk of ASCVD compared with women without a history of infertility. Atherosclerotic cardiovascular disease risk was much higher among nulliparous infertile women and among nulliparous infertile women who also had a pregnancy loss, suggesting that in these more extreme phenotypes, infertility may be associated with ASCVD risk.