The Jerusalem Perinatal Study cohort, 1964-2005: methods and a review of the main results

Association of common maternal infections with birth outcomes: a multinational cohort study

PURPOSE

It is unclear whether common maternal infections during pregnancy are risk factors for adverse birth outcomes. We assessed the association between self-reported infections during pregnancy with preterm birth and small-for-gestational-age (SGA) in an international cohort consortium.

METHODS

Data on 120,507 pregnant women were obtained from six population-based birth cohorts in Australia, Denmark, Israel, Norway, the UK and the USA. Self-reported common infections during pregnancy included influenza-like illness, common cold, any respiratory tract infection, vaginal thrush, vaginal infections, cystitis, urinary tract infection, and the symptoms fever and diarrhoea. Birth outcomes included preterm birth, low birth weight and SGA. Associations between maternal infections and birth outcomes were first assessed using Poisson regression in each cohort and then pooled using random-effect meta-analysis. Risk ratios (RR) and 95% confidence intervals (CI) were calculated, adjusted for potential confounders.

RESULTS

Vaginal infections (pooled RR, 1.10; 95% CI, 1.02-1.20) and urinary tract infections (pooled RR, 1.17; 95% CI, 1.09-1.26) during pregnancy were associated with higher risk of preterm birth. Similar associations with low birth weight were also observed for these two infections. Fever during pregnancy was associated with higher risk of SGA (pooled RR, 1.07; 95% CI, 1.02-1.12). No other significant associations were observed between maternal infections/symptoms and birth outcomes.

CONCLUSION

Vaginal infections and urinary infections during pregnancy were associated with a small increased risk of preterm birth and low birth weight, whereas fever was associated with SGA. These findings require confirmation in future studies with laboratory-confirmed infection diagnosis.

Signs of aging in midlife: physical function and sex differences in microbiota

Microbiota composition has been linked to physical activity, health measures, and biological age, but a shared profile has yet to be shown. The aim of this study was to examine the associations between microbiota composition and measures of function, such as a composite measure of physical capacity, and biological age in midlife, prior to onset of age-related diseases. Seventy healthy midlife individuals (age 44.58 ± 0.18) were examined cross-sectionally, and their gut-microbiota profile was characterized from stool samples using 16SrRNA gene sequencing. Biological age was measured using the Klemera-Doubal method and a composition of blood and physiological biomarkers. Physical capacity was calculated based on sex-standardized functional tests. We demonstrate that the women had significantly richer microbiota, p = 0.025; however, microbiota diversity was not linked with chronological age, biological age, or physical capacity for either women or men. Men had slightly greater β-diversity; however, β-diversity was positively associated with biological age and with physical capacity for women only (p = 0.01 and p = 0.04; respectively). For women, an increase in abundance of Roseburia faecis and Collinsella aerofaciens, as well as genus Ruminococcus and Dorea, was significantly associated with higher biological age and lower physical capacity; an increase in abundance of Akkermansia muciniphila and genera Bacteroides and Alistipes was associated with younger biological age and increased physical capacity. Differentially abundant taxa were also associated with non-communicable diseases. These findings suggest that microbiota composition is a potential mechanism linking physical capacity and health status; personalized probiotics may serve as a new means to support health-promoting interventions in midlife. Investigating additional factors underlying this link may facilitate the development of a more accurate method to estimate the rate of aging.

Obesity risk in young adults from the Jerusalem Perinatal Study (JPS): the contribution of polygenic risk and early life exposure

BACKGROUND/OBJECTIVES

The effects of early life exposures on offspring life-course health are well established. This study assessed whether adding early socio-demographic and perinatal variables to a model based on polygenic risk score (PRS) improves prediction of obesity risk.

METHODS

We used the Jerusalem Perinatal study (JPS) with data at birth and body mass index (BMI) and waist circumference (WC) measured at age 32. The PRS was constructed using over 2.1M common SNPs identified in genome-wide association study (GWAS) for BMI. Linear and logistic models were applied in a stepwise approach. We first examined the associations between genetic variables and obesity-related phenotypes (e.g., BMI and WC). Secondly, socio-demographic variables were added and finally perinatal exposures, such as maternal pre-pregnancy BMI (mppBMI) and gestational weight gain (GWG) were added to the model. Improvement in prediction of each step was assessed using measures of model discrimination (area under the curve, AUC), net reclassification improvement (NRI) and integrated discrimination improvement (IDI).

RESULTS

One standard deviation (SD) change in PRS was associated with a significant increase in BMI (β = 1.40) and WC (β = 2.45). These associations were slightly attenuated (13.7-14.2%) with the addition of early life exposures to the model. Also, higher mppBMI was associated with increased offspring BMI (β = 0.39) and WC (β = 0.79) (p < 0.001). For obesity (BMI ≥ 30) prediction, the addition of early socio-demographic and perinatal exposures to the PRS model significantly increased AUC from 0.69 to 0.73. At an obesity risk threshold of 15%, the addition of early socio-demographic and perinatal exposures to the PRS model provided a significant improvement in reclassification of obesity (NRI, 0.147; 95% CI 0.068-0.225).

CONCLUSIONS

Inclusion of early life exposures, such as mppBMI and maternal smoking, to a model based on PRS improves obesity risk prediction in an Israeli population-sample.

Perinatal exposures and adolescence overweight: The role of shared maternal-offspring pathways

BACKGROUND AND AIMS

Early life exposures affect offspring health across the life-course. We aimed to examine whether prevalent perinatal exposures and obstetric complications are independently associated with offspring overweight in adolescence. We then assessed whether shared maternal-offspring pathways drive the association of perinatal exposures with offspring overweight.

METHODS

Using data from the Jerusalem Perinatal Study birth cohort, two perinatal scores were constructed: obstetric complications (OC) and prevalent perinatal exposures (PPE) scores. PPE score, generated by principal component analysis, included three primary components. Logistic regressions were used to assess associations of scores with offspring overweight, with and without adjustment for maternal life-course survival.

RESULTS

OC and PPE scores were independently associated with offspring overweight (OROC = 1.15, 95%CI:1.07,1.25; ORPPE1- SEP and lifestyle = 0.85, 95%CI:0.79,0.91; ORPPE2- Maternal body size = 1.20, 95%CI: 1.13,1.28; ORPPE3-Fetal growth = 1.18, 95%CI:1.11,1.26). Maternal survival was associated with offspring overweight (OR = 1.38, 95%CI:1.08,1.76), yet introducing PPE score to the same model attenuated this association (OR = 1.16, 95%CI:0.90, 1.49). When OC score and maternal survival were included in the same model, their associations with offspring overweight remained unchanged.

CONCLUSIONS

Mother-offspring shared factors, captured by maternal life-course survival, underlie the effect of prevalent perinatal exposures on offspring overweight. However, the effect of obstetric complications was independent, highlighting the contribution of additional pathways.

Obesity Prediction in Young Adults from the Jerusalem Perinatal Study: Contribution of Polygenic Risk and Early Life Exposures

We assessed whether adding early life exposures to a model based on polygenic risk score (PRS) improves prediction of obesity risk. We used a birth cohort with data at birth and BMI and waist circumference (WC) measured at age 32. The PRS was composed of SNPs identified in GWAS for BMI. Linear and logistic models were used to explore associations with obesity-related phenotypes. Improvement in prediction was assessed using measures of model discrimination (AUC), and net reclassification improvement (NRI). One SD change in PRS was associated with a significant increase in BMI and WC. These associations were slightly attenuated (13.7%-14.2%) with the addition of early life exposures to the model. Also, higher maternal pre-pregnancy BMI was associated with increase in offspring BMI and WC (p<0.001). For prediction obesity (BMI ≥ 30), the addition of early life exposures to the PRS model significantly increase the AUC from 0.69 to 0.73. At an obesity risk threshold of 15%, the addition of early life exposures to the PRS model provided a significant improvement in reclassification of obesity (NRI, 0.147; 95% CI 0.068-0.225). We conclude that inclusion of early life exposures to a model based on PRS improves obesity risk prediction in an Israeli population-sample.

Familial aggregation of the aging process: biological age measured in young adult offspring as a predictor of parental mortality

Measures of biological age (BA) integrate information across organ systems to quantify "biological aging," i.e., inter-individual differences in aging-related health decline. While longevity and lifespan aggregate in families, reflecting transmission of genes and environments across generations, little is known about intergenerational continuity of biological aging or the extent to which this continuity may be modified by environmental factors. Using data from the Jerusalem Perinatal Study (JPS), we tested if differences in offspring BA were related to mortality in their parents. We measured BA using biomarker data collected from 1473 offspring during clinical exams in 2007-2009, at age 32 ± 1.1. Parental mortality was obtained from population registry data for the years 2004-2016. We fitted parametric survival models to investigate the associations between offspring BA and parental all-cause and cause-specific mortality. We explored potential differences in these relationships by socioeconomic position (SEP) and offspring sex. Participants' BAs widely varied (SD = 6.95). Among those measured to be biologically older, parents had increased all-cause mortality (HR = 1.10, 95% CI: 1.08, 1.13), diabetes mortality (HR = 1.19, 95% CI: 1.08, 1.30), and cancer mortality (HR = 1.07, 95% CI: 1.02, 1.13). The association with all-cause mortality was stronger for families with low compared with high SEP (P_interaction = 0.04) and for daughters as compared to sons (P_interaction < 0.001). Using a clinical-biomarker-based BA estimate, observable by young adulthood prior to the onset of aging-related diseases, we demonstrate intergenerational continuity of the aging process. Furthermore, variation in this familial aggregation according to household socioeconomic position (SEP) at offspring birth and between families of sons and daughters proposes that the environment alters individuals' aging trajectory set by their parents.

Pre- and Perinatal Factors Predicting Inflammatory Bowel Disease: A Population-Based Study with Fifty Years of Follow-Up

BACKGROUND

Pre- and perinatal events may be associated with an increased risk of inflammatory bowel disease [IBD]. We aimed to investigate the role of pre- and perinatal factors as potential risk factors for the development of IBD in a population with a follow-up of 50 years.

METHODS

We conducted a nested case-control study, reporting IBD incidence among individuals born in 1964-76, for whom pre- and perinatal exposures were reported as part of the Jerusalem Perinatal Study [JPS], by linking them to the database of the epidemiology group of the Israeli IBD Research Nucleus [epi-IIRN], including all IBD patients in Israel since 2005 and their matched controls.

RESULTS

We identified 2789 individuals within the epi-IIRN cohort who were also included in the JPS cohort [n = 90 079]: 746 IBD patients (405 with Crohn's disease [CD] and 341 with ulcerative colitis [UC]) and 2043 non-IBD controls. Those with a 'Non-western' family origin had decreased odds of developing CD and UC. High socioeconomic status was associated with CD but not UC. Low birth weight [≤2500 g] occurred less frequently in IBD cases compared to controls, especially in UC patients, showing a protective effect. Being the first born was associated with CD, and having older siblings lowered the odds of developing CD, decreasing 7% with each additional sibling. Smoking and breastfeeding data were available for a subset of individuals, but neither was associated with IBD development.

CONCLUSION

This population-based study identifies several pre- and perinatal variables as predictors of IBD development. This information may be helpful to facilitate implementation of early diagnosis interventions and family follow-up protocols.

Perinatal socio-behavioral and obstetric predictors of metabolically healthy and unhealthy obesity in adult offspring

OBJECTIVE

The purpose of this study was to investigate whether obstetric and perinatal socio-behavioral characteristics at the time of pregnancy predict obesity phenotypes of adult offspring.

METHODS

The Jerusalem Perinatal Study was conducted among 17,003 deliveries during 1974 to 1976. Follow-up studies were conducted during 2007 to 2009 and 2017 to 2019 among 1,440 offspring undergoing examinations. Offspring were classified into four phenotypes according to obesity and metabolic status: metabolically healthy normal weight (MHNW, reference group), unhealthy normal weight, healthy obesity (MHO), and unhealthy obesity (MUO). Regression models were carried out to identify perinatal predictors for risk phenotypes at age 30 to 35 years, emphasizing the differentiation between socio-behavioral and obstetric features.

RESULTS

A total of 15.7% of participants were classified as MUO, and 5.4% were classified as MHO. Low socioeconomic status was associated with both obesity phenotypes (e.g., odds ratio [OR]_MHO/MHNW = 2.98, p < 0.001). High socioeconomic status was associated with MUO (OR_MUO/MHNW = 1.93, p = 0.002). Maternal low education was also associated with both obesity phenotypes (OR_MUO/MHNW = 2.46, p < 0.001, OR_MHO/MHNW = 2.45, p = 0.005). Participants with MUO were more likely to have a smoking father (OR_MUO/MHNW = 1.48, p = 0.021).

CONCLUSIONS

Perinatal socio-behavioral characteristics are associated with adult obesity phenotypes. The findings point to possible mechanisms underlying the development of obesity in young adults and, thus, contribute toward identifying high-risk groups that would mostly benefit from obesity risk-reduction interventions.

Early-life factors and adult anti-Müllerian hormone levels

AIM

This study aims to examine whether early-life factors are associated with adult ovarian reserve, measured by anti-Müllerian hormone (AMH) levels.

METHODS

The work is based on the Jerusalem Perinatal Study (JPS), an extensive birth cohort with detailed information on all pregnancies and deliveries in Jerusalem between 1974 and 1976. A subset of individuals participated in a follow-up study that took place between 2007 and 2009 in which they completed questionnaires and were physically examined at mean age of 32. A blood sample was additionally drawn from each participant, and AMH was measured in a sample of 239 women. The associations between each early-life factors, including birth weight, maternal pre-pregnancy weight, gestational weight gain (GWG), socioeconomic position at birth, and parental smoking during pregnancy, were assessed with AMH levels at the age of 32.Multivariable regression models were used to examine the associations with AMH, adjusting for potential confounders at birth and at the age of 32.

RESULTS

Low birth weight was significantly associated with lower ovarian reserve reflected by lower levels of AMH at age 32 (range 30-36), independent of other early-life factors and after adjusting for confounders (β = 0.180, p = 0.03).

CONCLUSIONS

This prospective study demonstrates the association of birth weight and adult ovarian reserve. Underlying mechanisms are yet to be fully understood.

Covariate adjusted inference of parent-of-origin effects using case-control mother-child paired multilocus genotype data

It is of great interest to identify parent-of-origin effects (POEs) since POEs play an important role in many human heritable disorders and human early life growth and development. POE is sometimes referred to as imprinting effect in the literature. Compared with the standard logistic regression analyses, retrospective likelihood-based statistical methods are more powerful in identifying POEs when data are collected from related individuals retrospectively. However, none of existing retrospective-based methods can appropriately incorporate covariates that should be adjusted for if they are confounding factors. In this paper, a novel semiparametric statistical method, M-HAP, is developed to detect POEs by fully exploring available information from multilocus genotypes of case-control mother-child pairs and covariates. Some large sample properties are established for M-HAP. Finite sample properties of M-HAP are illustrated by extensive simulation studies and real data applications to the Jerusalem Perinatal Study and the Danish National Birth Cohort study, which confirm the desired superiority of M-HAP over some existing methods. M-HAP has been implemented in the updated R package CCMO.

Holocaust Experience and Mortality Patterns: 4-Decade Follow-up in a Population-Based Cohort

Research on mortality associated with exposure to the Holocaust is relevant for a better understanding of the effects of genocides on survivors. To our knowledge, previous studies have not investigated the long-term cause-specific mortality of Holocaust survivors. We compared mortality rates among Israelis born in European countries controlled by the Nazis during World War II with those among Israelis of European descent who did not have this exposure. Records of 22,671 people (45% women; 5,042 survivors) from the population-based Jerusalem Perinatal Study (1964-1976) were linked to the Israeli Population Registry, which was updated through 2016. Cox models were used for analysis, with 2-sided tests of statistical significance. Risk of all-cause mortality was higher among exposed women (hazard ratio (HR) = 1.15, 95% confidence interval (CI): 1.05, 1.27) than in unexposed women. No association was found between Holocaust exposure and male all-cause mortality. In both sexes, survivors had higher cancer-specific mortality (HR = 1.17 (95% CI: 1.01, 1.35) in women and HR = 1.14 (95% CI: 1.01, 1.28) in men). Exposed men also had excess mortality due to coronary heart disease (HR = 1.39, 95% CI: 1.09, 1.77) and lower mortality from other known causes combined (HR = 0.86, 95% CI: 0.75, 0.99). In summary, experiencing the Holocaust was associated with excess all-cause and cancer-specific mortality in women and cancer- and coronary heart disease-specific mortality in men.

Environmental mismatch and obesity in humans: The Jerusalem Perinatal Family Follow-Up Study

BACKGROUND

According to the hypothesis of Gluckman and Hanson, mismatch between the developmental and postdevelopmental environments may lead to detrimental health impacts such as obesity. While several animal studies support the mismatch theory, there is a scarcity of evidence from human-based studies.

OBJECTIVES

Our study aims to examine whether a mismatch between the developmental and young-adult environments affect obesity in young adults of the Jerusalem Perinatal Family Follow-Up Study.

METHODS

Data from The Jerusalem Perinatal Family Follow-Up Study birth cohort was used to characterize early and late environments using offspring and parental sociodemographic and lifestyle information at birth, age 32 (n = 1140) and 42 (n = 404). Scores characterizing the early and late environments were constructed using factor analysis. To assess associations of mismatch with obesity, regression models were fitted using the first factor of each environment and adiposity measures at age 32 and 42.

RESULTS

Having a stable non-beneficial environment at birth and young-adulthood was most strongly associated with increased adiposity, while a stable beneficial environment was most favorable. The transition from a beneficial environment at birth to a less beneficial environment at young-adulthood was associated with higher obesity measures, including higher BMI (β = 0.979; 95% CI: 0.029, 1.929), waist circumference (β = 2.729; 95% CI: 0.317, 5.140) and waist-hip ratio (β = 0.017; 95% CI: 0.004, 0.029) compared with those experiencing a beneficial environment at both time points. Transition from a less beneficial environment at birth to a beneficial environment at adulthood was also associated with higher obesity measurements (BMI -β = 1.116; 95% CI: 0.085, 2.148; waist circumference -β = 2.736; 95% CI: 0.215, 5.256).

CONCLUSIONS

This study provides some support for the mismatch hypothesis. While there is indication that an accumulation of the effects of the non-beneficial environment has the strongest detrimental impact on obesity outcomes, our results also indicate that a mismatch between the developmental and later environments may result in maladaptation of the individual leading to obesity.

Early predictors of mental health in mid-adulthood

AIM

Substantial research has focused on the examination of factors that contribute to the development of psychiatric problems. However, much less is known about factors early in life that may protect from poor mental health outcomes in midlife. This study aimed to identify the extent to which a set of key perinatal demographic variables and adolescent academic performance were associated with good mental health in mid-adulthood.

METHODS

In a sample of 525 individuals (aged 34-44, 55.4% male) born and raised in Jerusalem, Israel (STREAM study) we attempted to differentiate those who did and did not report psychiatric symptoms in mid-adulthood. Using χ² and regression analysis, we explored birth factors (year of birth, sex, birth weight, and number of older siblings, data on parental immigration and socioeconomic status), academic achievement in eighth grade and contemporaneous measures of lifestyle factors, personality traits, and perceived resilience.

RESULTS

Participants with good mental health were more often male (P = .005) and had better academic performance already at adolescence than participants who reported psychiatric symptoms in midlife (P < .001). They reported fewer physical complaints (P = .008), were less likely to smoke (P = .001) and considered themselves to be more "resilient" (P < .001).

CONCLUSIONS

The results showed that better academic performance in adolescence may be associated with better stress-coping strategies, resulting in fewer psychiatric complaints, more perceived resilience, and less stress-related behaviours in mid-adulthood. Future studies confirming this hypothesis could inform public mental health interventions.

Birth Weight and Maternal Body Size as Determinants of Blood Pressure at Age 17: Results from the Jerusalem Perinatal Study Cohort

OBJECTIVES

To investigate the effect of birth weight (BW) and maternal pre-pregnancy BMI (mBMI) on blood pressure (BP) in adolescence.

METHODS

A Population-based cohort of 11,729 births in Jerusalem during 1974-1976, with archival data on maternal and birth characteristics was performed. Measurements at age 17 were assessed and linear regression models were used to evaluate the associations of birth characteristics with BP outcomes.

RESULTS

BW was inversely associated with both systolic (SBP) and diastolic (DBP) BP at age 17 (SBP: B = - 0.829, p = 0.002; DBP: B = - 0.397, p = 0.033). The interaction term between BW and weight at age 17 was significant for DBP (p = 0.017) and pulse pressure (p = 0.005). mBMI yielded significant positive associations with BP, independent of BW.

CONCLUSIONS FOR PRACTICE

Our findings indicate that there are at least two distinct pathways linking early life characteristics with subsequent BP: Intrauterine growth, as reflected by BW and other genetic or environmental factors, reflected by mBMI and maternal education, contribute to offspring adolescent BP. These results warrant replication in other birth cohorts and underline the need to explore specific mechanisms that account for these associations.

Interpregnancy and interbirth intervals and all-cause, cardiovascular-related and cancer-related maternal mortality: findings from a large population-based cohort study

INTRODUCTION

Scarce research is available regarding the association between interbirth intervals (IBI) and long-term maternal health outcomes, particularly cardiovascular disease (CVD) mortality. We aimed to assess whether IBIs were associated with all-cause, CVD-related and cancer-related mortality.

METHODS

We conducted a cohort study in the setting of the Jerusalem Perinatal Study. Women with at least two consecutive singleton live births in 1964-1976 (N=18 294) were followed through 2016. IBIs were calculated as the interval between women's first and second cohort birth. We estimated associations between IBIs and mortality using Cox's proportional hazards models, adjusting for age, parity, maternal education, maternal origin and paternal socioeconomic status. Date of last menstrual period was available for a subset of women. We assessed the interpregnancy interval (IPI) for these women and compared the models using IPI and IBI.

RESULTS

During 868 079 years of follow up (median follow-up: 49.0 years), 3337 women died. Women with IBIs <15 months had higher all-cause mortality rates (HR 1.18; 95% CI 1.05 to 1.33) compared to women with 33-month to 68-month IBIs (reference category). IBI and CVD mortality appeared to have a J-shaped association; IBIs of <15, 15-20, 21-2626-2632, 33-68 and ≥69 months had HRs of 1.44, 1.40, 1.33, 1.14, 1.00 and 1.30, respectively. No substantial association was found with cancer mortality. Models using IPIs and those using IBI were similar.

CONCLUSION

Our results support the WHO recommendations for IPIs of ≥24 months and add additional evidence regarding long-term CVD mortality.

Short duration of marriage at conception as an independent risk factor for schizophrenia

Short duration of marriage (DoM) is a risk factor for preeclampsia that is also related to the risk for schizophrenia. This analysis examined the risk for schizophrenia associated with DoM and its independence from parental psychiatric disorders, parental ages and fathers' age at marriage.

METHOD

Relative Risks (RR) for schizophrenia were estimated using continuous and stratified Cox proportional hazards models in the 90,079 offspring from the prospective population-based Jerusalem birth cohort study (1964-1976). Schizophrenia diagnos in offspring and parental diagnoses of schizophrenia or other psychiatric conditions were identified by cross-linkage to Israel's psychiatric case registry. DoM and paternal age at marriage were abstracted from birth certificates.

RESULTS

In the full model, RR for schizophrenia decreased for each 5 years DoM: 0.83 (0.75-0.95), p_trend = 0.0015. Stratified analyses showed the greatest RR risk for DoM <2 years: 1.53 (1.11-1.66) with lesser risk for 2-4 years DoM: 1.38 (1.05-1.81) compared to more DOM of 10+ years. DoM effects were independent from parental psychiatric diagnoses (RRs = 2-6, p~0.00001), paternal age (1.34: p = 0.0001 /5 years- including fathers of 25-34 years). The apparent risk related to later fathers' age at marriage (1.27: p < 0.0001) was eliminated in after accounting for DoM and later paternal age.

CONCLUSIONS

Offspring born to couples married for less than 3 years, across all paternal ages, harbored a small increased risk for schizophrenia, which was independent of parental psychiatric disorders and paternal age. Fathers who married late had particularly short DoM, which, along with paternal age, completely explained the risks related to later paternal age at marriage. Further studies are needed to replicate these results and examine if pathogenic pathways include prenatal immune activation.

Mode of delivery and offspring adiposity in late adolescence: The modifying role of maternal pre-pregnancy body size

Objective

To study the association between mode of delivery and offspring BMI in late adolescence in a large cohort that predated the obesity epidemic, and assess the role of maternal pre-pregnancy BMI (ppBMI) in this association.

Study design

We conducted a historical prospective study in the setting of the Jerusalem Perinatal Study (JPS), a population-based cohort that includes all 17,003 births to residents of West Jerusalem, between 1974 and 1976. Offspring’s BMI at age 17 was obtained upon army recruitment and was available for 11,001 of cohort participants. The associations were examined using logistic regressions, adjusting for socio-demographic characteristics and for proxies for indication for C-Section birth. Analyses were then stratified by quartiles of ppBMI.

Results

C-Section was associated with offspring overweight/obesity, with adjusted OR of 1.44 (95%CI:1.14–1.82). Significant interaction of ppBMI with mode of delivery was observed, such that the associations of C-Section with overweight/obesity were limited to the upper quartile of ppBMI (adjusted OR = 1.70, 95%CI:1.18–2.43). Restricting the analyses to singleton first births and excluding pregnancies complicated with toxemia and gestational diabetes yielded similar findings.

Conclusions

C-Section was positively associated with being overweight/obese at age 17. Importantly, ppBMI modified this association, with a significant association between C-Section and overweight/obesity evident only among offspring born to mothers in the highest ppBMI quartile. In light of the growing rates of obesity in women of reproductive age, these results should be considered in patient-doctor shared decisions related to selection of mode of delivery, in the absence of a clear medical indication.

Associations of social environment, socioeconomic position and social mobility with immune response in young adults: the Jerusalem Perinatal Family Follow-Up Study

OBJECTIVES

Immune response to cytomegalovirus (CMV) impacts adult chronic disease. This study investigates associations of childhood and adulthood social environment, socioeconomic position (SEP) and social mobility with CMV response in young adults.

DESIGN

Historical prospective study design.

SETTING

Subcohort of all 17 003 births to residents of Jerusalem between 1974 and 1976.

PARTICIPANTS

Participants included 1319 young adults born in Jerusalem with extensive archival and follow-up data, including childhood and adulthood SEP-related factors and anti-CMV IgG titre levels and seroprevalence measured at age 32.

MAIN EXPOSURE AND OUTCOME MEASURES

Principal component analysis was used to transform correlated social environment and SEP-related variables at two time points (childhood and adulthood) into two major scores reflecting household (eg, number of siblings/children, religiosity) and socioeconomic (eg, occupation, education) components. Based on these components, social mobility variables were created. Linear and Poisson regression models were used to investigate associations of components and mobility with anti-CMV IgG titre level and seroprevalence, adjusted for confounders.

RESULTS

Lower levels of household and socioeconomic components in either childhood or adulthood were associated with higher anti-CMV IgG titre level and seropositivity at age 32. Compared with individuals with stable favourable components, anti-CMV IgG titre level and risk for seropositivity were higher in stable unfavourable household and socioeconomic components (household: β=3.23, P<0.001; relative risk (RR)=1.21, P<0.001; socioeconomic: β=2.20, P=0.001; RR=1.14, P=0.01), downward household mobility (β=4.32, P<0.001; RR=1.26, P<0.001) and upward socioeconomic mobility (β=1.37, P=0.04; RR=1.19, P<0.001). Among seropositive individuals, associations between household components and mobility with anti-CMV IgG titre level were maintained and associations between socioeconomic components and mobility with anti-CMV IgG titre level were attenuated.

CONCLUSIONS

Our study provides evidence that accumulating low SEP from childhood through adulthood and social mobility may compromise immune response in young adulthood.

Live birth sex ratios and father's geographic origins in Jerusalem, 1964-1976

OBJECTIVE

To examine whether ancestry influenced sex ratios of offspring in a birth cohort before parental antenatal sex selection influenced offspring sex.

METHODS

We measured the sex ratio as the percent of males according to countries of birth of paternal and maternal grandfathers in 91,459 live births from 1964 to 1976 in the Jerusalem Perinatal Study. Confidence limits (CI) were computed based on an expected sex ratio of 1.05, which is 51.4% male.

RESULTS

Of all live births recorded, 51.4% were male. Relative to Jewish ancestry (51.4% males), significantly more males (1,761) were born to Muslim ancestry (54.5, 95% CI = 52.1-56.8, P = 0.01). Among the former, sex ratios were not significantly associated with paternal or maternal age, education, or offspring's birth order. Consistent with a preference for male offspring, the sex ratio decreased despite increasing numbers of births over the 13-year period. Sex ratios were not affected by maternal or paternal origins in North Africa or Europe. However, the offspring whose paternal grandfathers were born in Western Asia included fewer males than expected (50.7, 50.1-51.3, P = 0.02), whether the father was born abroad (50.7) or in Israel (50.8). This was observed for descendents of paternal grandfathers born in Lebanon (47.6), Turkey (49.9), Yemen & Aden (50.2), Iraq (50.5), Afghanistan (50.5), Syria (50.6), and Cyprus (50.7); but not for those from India (51.5) or Iran (51.9). The West Asian group showed the strongest decline in sex ratios with increasing paternal family size.

CONCLUSIONS

A decreased sex ratio associated with ancestry in Western Asia is consistent with reduced ability to bear sons by a subset of Jewish men in the Jerusalem cohort. Lower sex ratios may be because of pregnancy stress, which may be higher in this subgroup. Alternatively, a degrading Y chromosome haplogroup or other genetic or epigenetic differences on male germ lines could affect birth ratios, such as differential exposure to an environmental agent, dietary differences, or stress. Differential stopping behaviors that favor additional pregnancies following the birth of a daughter might exacerbate these lower sex ratios.

Accounting for Life-Course Exposures in Epigenetic Biomarker Association Studies: Early Life Socioeconomic Position, Candidate Gene DNA Methylation, and Adult Cardiometabolic Risk

Recent studies suggest that epigenetic programming may mediate the relationship between early life environment, including parental socioeconomic position, and adult cardiometabolic health. However, interpreting associations between early environment and adult DNA methylation may be difficult because of time-dependent confounding by life-course exposures. Among 613 adult women (mean age = 32 years) of the Jerusalem Perinatal Study Family Follow-up (2007-2009), we investigated associations between early life socioeconomic position (paternal occupation and parental education) and mean adult DNA methylation at 5 frequently studied cardiometabolic and stress-response genes (ABCA1, INS-IGF2, LEP, HSD11B2, and NR3C1). We used multivariable linear regression and marginal structural models to estimate associations under 2 causal structures for life-course exposures and timing of methylation measurement. We also examined whether methylation was associated with adult cardiometabolic phenotype. Higher maternal education was consistently associated with higher HSD11B2 methylation (e.g., 0.5%-point higher in 9-12 years vs. ≤8 years, 95% confidence interval: 0.1, 0.8). Higher HSD11B2 methylation was also associated with lower adult weight and total and low-density lipoprotein cholesterol. We found that associations with early life socioeconomic position measures were insensitive to different causal assumption; however, exploratory analysis did not find evidence for a mediating role of methylation in socioeconomic position-cardiometabolic risk associations.

Associations of socioeconomic position in childhood and young adulthood with cardiometabolic risk factors: the Jerusalem Perinatal Family Follow-Up Study

BACKGROUND

Several stages in the life course have been identified as important to the development of cardiovascular disease. This study aimed to assess the associations of childhood and adulthood socioeconomic position (SEP) and social mobility with cardiometabolic risk factors (CMRs) later in life.

METHODS

We conducted follow-up examinations of 1132 offspring, aged 32, within a population-based cohort of all births in Jerusalem from 1974 to 1976. SEP was indicated by parents' occupation and education, and adulthood SEP was based on offspring's occupation and education recorded at age 32. Linear regression models were used to investigate the associations of SEP and social mobility with CMRs.

RESULTS

Childhood-occupational SEP was negatively associated with body mass index (BMI; β=-0.29, p=0.031), fat percentage (fat%; β=-0.58, p=0.005), insulin (β=-0.01, p=0.031), triglycerides (β=-0.02, p=0.024) and low-density lipoprotein cholesterol (LDL-C; β=-1.91, p=0.015), independent of adulthood SEP. Adulthood-occupational SEP was negatively associated with waist-to-hip ratio (WHR; β=-0.01, p=0.002), and positively with high-density lipoprotein cholesterol (HDL-C; β=0.87, p=0.030). Results remained similar after adjustment for smoking and inactivity. Childhood-educational SEP was associated with decreased WHR and LDL-C level (p=0.0002), and adulthood-educational SEP was inversely associated with BMI (p=0.001), waist circumference (p=0.008), WHR (p=0.001) and fat% (p=0.0002) and positively associated with HDL-C (p=0.030). Additionally, social mobility (mainly upward) was shown to have adverse cardiometabolic outcomes.

CONCLUSIONS

Both childhood and adulthood SEP contribute independently to CMR. The match-mismatch hypothesis may explain the elevated CMRs among participants experiencing social mobility. Identification of life-course SEP-related aspects that translate into social inequality in cardiovascular risk may facilitate efforts for improving health and for reducing disparities in cardiovascular disease.

Mortality, cancer incidence, and survival in parents after bereavement

PURPOSE

The study objective was to investigate whether child loss is related to mortality, cancer incidence, and cancer survival in parents.

METHODS

We used a population-based birth cohort (1964-1976) in Jerusalem and ascertained mortality (average follow-up of 39.1 years) and any cancer (average follow-up of 35.6 years) among parents who lost a child (2838 mothers and 2532 fathers) and among nonbereaved parents (38,212 mothers and 36,433 fathers). We also assessed mortality among parents with cancer. Time-dependent Cox models were used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs).

RESULTS

Overall mortality rates among bereaved parents were modestly increased when compared with nonbereaved parents (HR = 1.18, 95% CI: 1.05-1.32 in mothers; HR = 1.10, 95% CI: 1.01-1.20 in fathers). Hazard models indicated a significant relationship between bereavement and deaths from coronary heart disease in mothers (HR = 1.90, 95% CI: 1.23-2.95) and circulatory causes in both parents (HR = 1.69; 95% CI: 1.22-2.34 in mothers and HR = 1.25; 95% CI: 1.02-1.54 in fathers). Bereavement was not associated with parental risk of cancer disease and with survival from cancer. The association between bereavement and parental overall mortality was similar in the different parental sociodemographic characteristics. We observed a decrease in HRs for parental mortality associated with bereavement, with increasing time since the death of the child (HRs = 9-10, 0-3 years; HRs = 0.9-1.0, 9+ years; P(heterogeneity) ≤ 3 × 10(-32)). A similar decrease in HRs was observed for parental survival from cancer (HRs = 6.7-8.7, 0-3 years; HRs = 0.9-1.0, 9+ years).

CONCLUSIONS

Our study suggests that child loss was associated with slightly increased risk of all-cause and circulatory mortality in parents but not with incidence of cancer and cancer survival. The considerable increased parental mortality during a short period after child loss support the involvement of pathways related to psychological stress.

Grand multiparity and reproductive cancer in the Jerusalem Perinatal Study Cohort

OBJECTIVES

Grand multiparity is associated with reduced mortality from reproductive cancers. We aimed to separate the components of mortality, by measuring incidence of and survival after reproductive cancer onset in grand multiparous compared to other parous women.

STUDY DESIGN

We linked data from the population-based Jerusalem Perinatal Study Cohort, which included women aged 13-55 who delivered 1964-1976, with Israel's National Cancer Registry. We compared breast and gynecologic cancer risk and all-cause survival following a cancer diagnosis, among grand multiparae (GMPs = parity 5+, n = 8,246) versus women with parity 1-4 (n = 19,703), adjusting for reproductive and demographic variables.

RESULTS

Grand multiparae were at significantly lower risk of breast cancer than others (adjusted hazard ratio (HRadj) = 0.62, 95 % confidence interval (CI) 0.54-0.71), after controlling for age at first birth, education, and other covariates. This reduction was greater among GMPs whose first birth occurred after age 30 (p-interaction = 0.0001) and for cancer occurring before age 50 years (p = 0.002). In contrast, GMPs were at greater risk of death than women with parity <5, following a breast cancer diagnosis (HRadj = 1.69, CI 1.39-2.1). Ovarian, uterine, and cervical cancer incidence did not differ between the groups, but survival was reduced for GMPs with uterine cancer (HRadj = 2.48, CI 1.22-5.03).

CONCLUSION

Reduced reproductive cancer mortality reported among GMPs masks two opposing phenomena: decreased breast cancer risk and poorer survival after breast and uterine cancers. The latter unfavorable outcome suggests that tumors in GMPs may be particularly aggressive, having perhaps escaped protective mechanisms conferred by parity. This finding calls for heightened clinical attention in this group.

Study of resilience and environmental adversity in midlife health (STREAM)

PURPOSE

The Jerusalem study of resilience and environmental adversity in midlife health (STREAM) was established to examine the prevalence of common mental and physical health issues in mid-adulthood in the inner city of Jerusalem, and to examine their association with lifespan psychosocial factors of vulnerability and resilience.

METHOD

Participants were 811 randomly selected individuals from 7000 individuals who were born and grew up in inner-Jerusalem. Participants were 34-44 years old during first wave of STREAM assessment. Initial telephone surveys took place in 2007-2008 and participants were followed-up for a second survey 1 year later. Upon funding, a new wave is planned for 2017-2018. Survey topics comprised common health problems (e.g., type 2 diabetes/migraine), health markers (e.g., BMI), and psychiatric vulnerabilities (e.g., anxiety, post-traumatic stress, depressive symptoms, psychosis). Other measures included socioeconomic status, creativity, life style behavior (e.g., smoking, exercise), social contact and adaptation to change. Survey data were retrospectively merged with data of national registry sources that included adverse psychosocial factors, psychiatric and social measures assessed across all developmental stages through midlife. This includes data available on birth factors, school achievement and adjustment, cognitive and behavioral functioning during young adulthood, psychiatric hospitalizations, immigration and socioeconomic status.

RESULTS

Results on health outcomes of the first STREAM wave indicate that prevalence rates of health problems are comparable to recent World Mental Health Surveys.

CONCLUSIONS

Apart from measures on adverse psychosocial factors, STREAM provides a cohort to examine resilience to developing health problems and having a poor health and functional outcome.

Socioeconomic disparities in breast cancer incidence and survival among parous women: findings from a population-based cohort, 1964-2008

Background

Socioeconomic position (SEP) has been associated with breast cancer incidence and survival. We examined the associations between two socioeconomic indicators and long-term breast cancer incidence and survival in a population-based cohort of parous women.

Methods

Residents of Jerusalem who gave birth between 1964–1976 (n = 40,586) were linked to the Israel Cancer Registry and Israel Population Registry to determine breast cancer incidence and vital status through mid-2008. SEP was assessed by husband’s occupation and the woman’s education. We used log ranks tests to compare incidence and survival curves by SEP, and Cox proportional hazard models to adjust for demographic, reproductive and diagnostic factors and assess effect modification by ethnic origin.

Results

In multivariable models, women of high SEP had a greater risk of breast cancer compared to women of low SEP (Occupation: HR 1.18, 95 % CI 1.03-1.35; Education: HR 1.39, 95 % CI 1.21-1.60) and women of low SEP had a greater risk of mortality after a breast cancer diagnosis (Occupation: HR 1.33, 95 % CI 1.04-1.70; Education: HR 1.37, 95 % CI 1.06-1.76). The association between education and survival was modified by ethnic origin, with a gradient effect observed only among women of European origin. Women of Asian, North African and Israeli origin showed no such trend.

Conclusions

SEP was associated with long-term breast cancer incidence and survival among Israeli Jews. Education had a stronger effect on breast cancer outcomes than occupation, suggesting that a behavioral mechanism may underlie disparities. More research is needed to explain the difference in the effect of education on survival among European women compared to women of other ethnicities.

Parent-of-Origin Effects of the APOB Gene on Adiposity in Young Adults

Loci identified in genome-wide association studies (GWAS) of cardio-metabolic traits account for a small proportion of the traits' heritability. To date, most association studies have not considered parent-of-origin effects (POEs). Here we report investigation of POEs on adiposity and glycemic traits in young adults. The Jerusalem Perinatal Family Follow-Up Study (JPS), comprising 1250 young adults and their mothers was used for discovery. Focusing on 18 genes identified by previous GWAS as associated with cardio-metabolic traits, we used linear regression to examine the associations of maternally- and paternally-derived offspring minor alleles with body mass index (BMI), waist circumference (WC), fasting glucose and insulin. We replicated and meta-analyzed JPS findings in individuals of European ancestry aged ≤50 belonging to pedigrees from the Framingham Heart Study, Family Heart Study and Erasmus Rucphen Family study (total N≅4800). We considered p<2.7x10^-4 statistically significant to account for multiple testing. We identified a common coding variant in the 4^th exon of APOB (rs1367117) with a significant maternally-derived effect on BMI (β = 0.8; 95%CI:0.4,1.1; p = 3.1x10^-5) and WC (β = 2.7; 95%CI:1.7,3.7; p = 2.1x10^-7). The corresponding paternally-derived effects were non-significant (p>0.6). Suggestive maternally-derived associations of rs1367117 were observed with fasting glucose (β = 0.9; 95%CI:0.3,1.5; p = 4.0x10^-3) and insulin (ln-transformed, β = 0.06; 95%CI:0.03,0.1; p = 7.4x10^-4). Bioinformatic annotation for rs1367117 revealed a variety of regulatory functions in this region in liver and adipose tissues and a 50% methylation pattern in liver only, consistent with allelic-specific methylation, which may indicate tissue-specific POE. Our findings demonstrate a maternal-specific association between a common APOB variant and adiposity, an association that was not previously detected in GWAS. These results provide evidence for the role of regulatory mechanisms, POEs specifically, in adiposity. In addition this study highlights the benefit of utilizing family studies for deciphering the genetic architecture of complex traits.

To date, genetic variants identified in large-scale genetic studies using recent technical and methodological advances explain only a small proportion of the genetic basis of obesity, diabetes and other cardiovascular risk factors. These studies were typically conducted in samples of unrelated individuals. Here we utilize a family-based approach to identify genetic variants associated with obesity-related traits. Specifically, we examined the separate contribution of maternally- vs. paternally-inherited common genetic variants to these traits. By examining 1250 young adults and their mothers from Jerusalem, we show that a specific genetic variant, rs1367117, located in the APOB gene on chromosome 2 is related to body mass index and waist circumference when inherited from mother and not from father. This maternal effect is not restricted to Jerusalemites, but is also seen in a large sample of individuals of European descent from independent family studies worldwide. Our findings provide support of the role of complex genetic mechanisms in obesity, and highlight the benefit of utilizing family studies for uncovering genetic pathways underlying common risk factors and diseases.

De novo mutations from sporadic schizophrenia cases highlight important signaling genes in an independent sample

Schizophrenia is a debilitating syndrome with high heritability. Genomic studies reveal more than a hundred genetic variants, largely nonspecific and of small effect size, and not accounting for its high heritability. De novo mutations are one mechanism whereby disease related alleles may be introduced into the population, although these have not been leveraged to explore the disease in general samples. This paper describes a framework to find high impact genes for schizophrenia. This study consists of two different datasets. First, whole exome sequencing was conducted to identify disruptive de novo mutations in 14 complete parent-offspring trios with sporadic schizophrenia from Jerusalem, which identified 5 sporadic cases with de novo gene mutations in 5 different genes (PTPRG, TGM5, SLC39A13, BTK, CDKN3). Next, targeted exome capture of these genes was conducted in 48 well-characterized, unrelated, ethnically diverse schizophrenia cases, recruited and characterized by the same research team in New York (NY sample), which demonstrated extremely rare and potentially damaging variants in three of the five genes (MAF<0.01) in 12/48 cases (25%); including PTPRG (5 cases), SCL39A13 (4 cases) and TGM5 (4 cases), a higher number than usually identified by whole exome sequencing. Cases differed in cognition and illness features based on which mutation-enriched gene they carried. Functional de novo mutations in protein-interaction domains in sporadic schizophrenia can illuminate risk genes that increase the propensity to develop schizophrenia across ethnicities.

Parental smoking during pregnancy and offspring cardio-metabolic risk factors at ages 17 and 32

OBJECTIVE

To examine the association of maternal and/or paternal smoking during pregnancy with offspring cardio-metabolic risk (CMR) factors at adolescence and early adulthood, taking into account socio-demographic, medical and lifestyle characteristics of parents and offspring, as well as offspring common genetic variation.

METHODS

We used a population-based cohort of all 17 003 births in Jerusalem during 1974-76, with available archival data on parental and birth characteristics. Measurements at age 17 were assessed at military induction examinations for 11 530 offspring. 1440 offspring from the original 1974-1976 birth cohort were sampled using a stratified sampling approach, and were interviewed and examined at age 32. Parental smoking during pregnancy (i.e. maternal, paternal and any parent) was primarily defined dichotomously (any number of cigarettes smoked daily by mother or father during pregnancy vs. non-smokers). Additionally, smoking was assessed by quantity of cigarettes smoked daily. Linear regression models were used to evaluate the associations of parental smoking during pregnancy with various offspring CMR factors, after controlling for potential confounders and for genetic variation in candidate genes.

RESULTS

Prevalence of exposure to parental smoking in-utero (i.e. smoking of any parent) was 53.2% and 48.4% among the 17 years old and 32 years old samples, respectively. At age 17, smoking of at least one parent during pregnancy was significantly associated with weight (B = 1.39), height (B = 0.59), BMI (B = 0.32) and pulse rate (B = -0.78) (p-values < 0.001). At age 32, parental smoking, adjusted for covariates, was associated with 2.22 kg higher mean offspring weight, 0.95 cm higher mean offspring height, 0.57 kg/m(2) higher BMI, and 1.46 cm higher waist-circumference (p-values ≤ 0.02). Similar results, reflecting a dose response, were observed when maternal and paternal smokings were assessed by number of cigarettes smoked daily.

CONCLUSIONS

This prospective study demonstrates a potential long-term adverse effect of parental smoking during pregnancy on offspring health and calls for increasing efforts to promote smoking cessation of both parents before pregnancy.

Associations of maternal pre-pregnancy and gestational body size with offspring longitudinal change in BMI

OBJECTIVES

Studies demonstrate associations between changes in obesity-related phenotypes and cardiovascular risk. Although maternal pre-pregnancy BMI (mppBMI) and gestational weight gain (GWG) may be associated with adult offspring adiposity, no study has examined associations with obesity changes. Associations of mppBMI and GWG with longitudinal change in offspring's BMI (ΔBMI) were examined, and whether associations are explained by offspring genetics was assessed.

METHODS

A birth cohort of 1400 adults, with data at birth, age 17 and 32 years was used. After genotyping offspring, genetic scores, predictive of exposures and outcome were created, and linear regression models with and without scores were fit to examine the associations of mppBMI and GWG with ΔBMI.

RESULTS

A one SD change in mppBMI and GWG was associated with a 0.83 and a 0.75 kg/m² increase in ΔBMI, respectively. The association between mppBMI and offspring ΔBMI was slightly attenuated (12%) with the addition of genetic scores. In the GWG model, a significant substantial 28.2% decrease in the coefficient was observed.

CONCLUSIONS

This study points to an association between maternal excess weight in pregnancy and offspring BMI change from adolescence to adulthood. Genetic factors may account, in part, for GWG/ΔBMI association. These findings broaden observations that maternal obesity-related phenotypes have long-term consequences for offspring health.

Maternal genetic variation accounts in part for the associations of maternal size during pregnancy with offspring cardiometabolic risk in adulthood

BACKGROUND

Maternal pre-pregnancy body-mass index (ppBMI) and gestational weight gain (GWG) are associated with cardiometabolic risk (CMR) traits in the offspring. The extent to which maternal genetic variation accounts for these associations is unknown.

METHODS/RESULTS

In 1249 mother-offspring pairs recruited from the Jerusalem Perinatal Study, we used archival data to characterize ppBMI and GWG and follow-up data from offspring to assess CMR, including body mass index (BMI), waist circumference, glucose, insulin, blood pressure, and lipid levels, at an average age of 32. Maternal genetic risk scores (GRS) were created using a subset of SNPs most predictive of ppBMI, GWG, and each CMR trait, selected among 1384 single-nucleotide polymorphisms (SNPs) characterizing variation in 170 candidate genes potentially related to fetal development and/or metabolic risk. We fit linear regression models to examine the associations of ppBMI and GWG with CMR traits with and without adjustment for GRS. Compared to unadjusted models, the coefficient for the association of a one-standard-deviation (SD) difference in GWG and offspring BMI decreased by 41% (95%CI -81%, -11%) from 0.847 to 0.503 and the coefficient for a 1SD difference in GWG and WC decreased by 63% (95%CI -318%, -11%) from 1.196 to 0.443. For other traits, there were no statistically significant changes in the coefficients for GWG with adjustment for GRS. None of the associations of ppBMI with CMR traits were significantly altered by adjustment for GRS.

CONCLUSIONS

Maternal genetic variation may account in part for associations of GWG with offspring BMI and WC in young adults.

Mode of delivery and offspring body mass index, overweight and obesity in adult life: a systematic review and meta-analysis

Background

It has been suggested that mode of delivery, a potentially powerful influence upon long-term health, may affect later life body mass index (BMI). We conducted a systematic review and meta-analysis of the effect of Caesarean section (CS) and vaginal delivery (VD) on offspring BMI, overweight (BMI>25) and obesity (BMI>30) in adulthood. Secondary outcomes were subgroup analyses by gender and type of CS (in-labour/emergency, pre-labour/elective).

Methods

Using a predefined search strategy, Pubmed, Google Scholar and Web of Science were searched for any article published before 31^st March 2012, along with references of any studies deemed relevant. Studies were selected if they reported birth characteristics and long-term offspring follow-up into adulthood. Aggregate data from relevant studies were extracted onto a pre-piloted data table. A random-effects meta-analysis was carried out in RevMan5. Results are illustrated using forest plots and funnel plots, and presented as mean differences or odds ratios (OR) and 95% confidence intervals.

Results

Thirty-five studies were identified through the search, and 15 studies with a combined population of 163,753 were suitable for inclusion in the meta-analysis. Comparing all CS to VD in pooled-gender unadjusted analyses, mean BMI difference was 0·44 kg·m^-2 (0·17, 0·72; p = 0·002), OR for incidence of overweight was 1·26 (1·16, 1·38; p<0·00001) and OR for incidence of obesity was 1·22 (1·05, 1·42; p = 0·01). Heterogeneity was low in all primary analyses. Similar results were found in gender-specific subgroup analyses. Subgroup analyses comparing type of CS to VD showed no significant impact on any outcome.

Conclusions

There is a strong association between CS and increased offspring BMI, overweight and obesity in adulthood. Given the rising CS rate worldwide there is a need to determine whether this is causal, or reflective of confounding influences.

Systematic review registration

An a priori protocol was registered on PROSPERO (registration number: CRD42011001851)

Prenatal stress and affective disorders in a population birth cohort

OBJECTIVES

Pregnant women exposed to an acute traumatic event are thought to produce offspring with an increased incidence of affective disorders. It is not known whether there are specific times in pregnancy which confer increased vulnerability, or if psychosocial stress alone can increase the incidence of affective disorders in offspring. We examined the relationship of the timing of an acute psychosocial threat during pregnancy to the incidence of affective disorders in offspring using data from a large birth cohort.

METHODS

Using data on 90079 offspring born in Jerusalem in 1964-1976 and linked to Israel's psychiatric registry, we constructed proportional hazards models to evaluate the link between gestational age during the Arab-Israeli war of June 1967 and incidence of mood disorders.

RESULTS

Those in their first trimester of fetal development during the war were more likely to be admitted to hospitals for any mood disorders [relative risk (RR) = 3.01, 95% confidence interval (CI): 1.68-5.39, p = 0.0002]; for bipolar disorder the risk was doubled (RR = 2.44, 95% CI: 0.996-5.99, p = 0.054) and for all 'other' mood disorders the risk was tripled (RR = 3.61, 95% CI: 1.68-7.80, p = 0.001). Mood disorders were also increased in offspring whose mothers had been in the third month of pregnancy in June of 1967 (RR = 5.54, 95% CI: 2.73-11.24, p < 0.0001).

CONCLUSIONS

A time-limited exposure to a severe threat during early gestation may be associated with an increased incidence of affective disorders in offspring. The third month of fetal development was a moment of special vulnerability.

Association between number of children and mortality of mothers: results of a 37-year follow-up study

PURPOSE

To examine the association between parity and long-term, all-cause mortality and mortality owing to specific causes in women.

METHODS

This prospective population-based study included 40,454 mothers who gave birth in Western Jerusalem, Israel, to 125,842 children and were followed for an average of 37 years after the birth of their first child. Cox proportional hazards models were used to evaluate long-term total and specific-cause mortality of women by their parity.

RESULTS

We found a U-shaped relationship between the number of offspring and risk of all-cause mortality in mothers. After adjustment for sociodemographic characteristics and maternal health and obstetric conditions, higher mortality rates were observed for mothers of 1 child (hazard ratio [HR], 1.18; 95% confidence interval [CI], 1.04-1.4), mothers of 5 to 9 children (HR, 1.21; 95% CI, 1.09-1.33), and mothers of 10 or more children (HR, 1.49; 95% CI, 1.12-1.99) compared with mothers of 2 to 4 children. Mortality risk from specific causes including coronary disease, circulatory disease, and cancer were increased for multiparous women.

CONCLUSIONS

In this long-term follow-up study, there was an association between number of children and mortality risk for mothers. These findings suggest that maternal pregnancies and postnatal characteristics as reflected by number of children may have consequences for long-term maternal health.

Associations of maternal prepregnancy body mass index and gestational weight gain with adult offspring cardiometabolic risk factors: the Jerusalem Perinatal Family Follow-up Study

BACKGROUND

Accumulating evidence demonstrates that both maternal prepregnancy body mass index (mppBMI) and gestational weight gain (GWG) are associated with adult offspring adiposity. However, whether these maternal attributes are related to other cardiometabolic risk factors in adulthood has not been comprehensively studied.

METHODS AND RESULTS

We used a birth cohort of 1400 young adults born in Jerusalem who had extensive archival data and clinical information at 32 years of age to prospectively examine the associations of mppBMI and GWG with adiposity and related cardiometabolic outcomes. Greater mppBMI, independently of GWG and confounders, was significantly associated with higher offspring BMI, waist circumference, systolic and diastolic blood pressures, insulin, and triglycerides and with lower high-density lipoprotein cholesterol. For example, the effect sizes were translated to nearly 5 kg/m(2) higher mean BMI, 8.4 cm higher waist circumference, 0.13 mmol/L (11.4 mg/dL) higher triglycerides, and 0.10 mmol/L (3.8 mg/dL) lower high-density lipoprotein cholesterol among offspring of mothers within the upper mppBMI quartile (mppBMI >26.4 kg/m(2)) compared with the lower quartile (mppBMI <21.0 kg/m(2)). GWG, independently of mppBMI, was positively associated with offspring adiposity; differences of 1.6 kg/m(2) in BMI and 2.4 cm in waist were observed when offspring of mothers in the upper (GWG >14 kg) and lower (GWG <9 kg) quartiles of GWG were compared. Further adjustment for offspring adiposity attenuated the observed associations to the null.

CONCLUSIONS

Maternal size both before and during pregnancy is associated with cardiometabolic risk factors in young adult offspring. The associations appear to be driven mainly by offspring adiposity. Future studies that explore mechanisms underlying the intergenerational cycle of obesity are warranted to identify potentially novel targets for cardiometabolic risk-reduction interventions.

Catatonic schizophrenia: a cohort prospective study

BACKGROUND

In the 20th century, catatonia was usually deemed a subtype of schizophrenia. Recently, the nature and classification of catatonia are being reconsidered. This study is the first to describe catatonia using prospectively collected data and to examine how catatonic schizophrenia differs from, or resembles, other types of schizophrenia.

METHODS

Data were analyzed in a cohort of 90,079 offspring followed from birth till ages 29-41 years. Proportional hazards models were used, calculating time to first psychiatric hospital admission, to compare risk factors for catatonic schizophrenia vs "other schizophrenia."

RESULTS

Of 568 cases of schizophrenia, 43 (7.6%) had catatonic schizophrenia. The sexes were equally at risk for catatonic schizophrenia in contrast to other schizophrenia, for which the incidence was higher in males (1.70, 1.42-2.03, P < .0001). Advancing paternal age had no influence on the risk of catatonic schizophrenia in contrast to other schizophrenia, in which the risk to offspring of fathers age 35+ was 1.27 (1.03-1.57, P = .03) compared with those of younger fathers. Those with catatonic schizophrenia were somewhat more likely to have older mothers (aged 35+) (relative risk = 2.14, 0.85-5.54) while maternal age was not related to other schizophrenia. Both were equally affected by parental history of schizophrenia. Patients with catatonia were significantly more likely to attempt suicide (P = .006).

CONCLUSION

Patients with catatonic schizophrenia show a somewhat different profile of risk factors from those with other types of schizophrenia in this cohort and are more likely to attempt suicide. This lends some support to the hypothesis that catatonic schizophrenia may have a distinct etiology.

Age, sex and first treatment of schizophrenia in a population cohort

OBJECTIVE

Schizophrenia affects men more than women, but this may not be true at all ages. This study examines the incidence of first hospitalization for treatment of schizophrenia in each sex over different ages.

METHODS

We compared the incidence of first admission for treatment in a cohort of 46,388 males and 43,680 females followed from birth until ages 29-41, using life tables and proportional hazards methods.

RESULTS

Life table estimates of cumulative incidence by age 40 were 1.44% in males and 0.86% in females. For over all ages the relative risk (RR) in males was 1.6 (95% confidence limits=1.4-1.8) compared with females. Before age 17 there was no significant difference between the sexes (RR=0.86, 0.56-1.3). Excess risk in males was observed only from age 17 (RR=1.7, 1.4-1.9). There was no evidence of the incidence in females catching up with that in males, during the 30s.

CONCLUSION

In this population, there was a significant change, over age, in the relative incidence of first hospitalization for schizophrenia between the sexes; the excess incidence in males first developed at age 17.

Older paternal age strongly increases the morbidity for schizophrenia in sisters of affected females

The effect of a family history of schizophrenia on the risk for this disorder in the offspring has rarely been examined in a prospective population cohort accounting for the sex of the proband and the first-degree relatives, and certainly not with respect to later paternal age. The influence of affected relatives on offspring risk of schizophrenia was estimated using Cox proportional hazards regression in models that accounted for sex, relation of affected first degree relatives and paternal age in the prospective population-based cohort of the Jerusalem Perinatal Schizophrenia Study. Of all first-degree relatives, an affected mother conferred the highest risk to male and female offspring among the cases with paternal age <35 years, however, female offspring of fathers ≥35 years with an affected sister had the highest risk (RR = 8.8; 95% CI = 3.9-19.8). The risk seen between sisters of older fathers was fourfold greater than the risk to sisters of affected females of younger fathers (RR = 2.2, 95% CI 0.7-6.7). The test for interaction was significant (P = 0.03). By contrast, the risk of schizophrenia to brothers of affected males was only doubled between older (RR = 3.3, 95% 1.6-6.6) and younger fathers (RR = 1.6, 95% CI 0.7-3.5). The most striking finding from this study was the very large increase in risk of schizophrenia to sisters of affected females born to older fathers. The authors speculate that the hypothesized paternally expressed genes on the X chromosome might play some role in these observations.

Time-to-pregnancy and risk of schizophrenia

Schizophrenia has been linked to advanced paternal age, but the explanation is unknown. We questioned whether the incidence of schizophrenia would be related to male reproductive capacity, as reflected in the time taken to conceive. We measured the incidence of schizophrenia in relation to time to conception in a sub-group of 12,269 in the Jerusalem cohort whose mothers, interviewed post-partum, reported that the pregnancy had been intended. Compared with those conceived in less than 3 months, the unadjusted relative risks (RR) of schizophrenia associated with conception-waits of 3-5, 6-11 and 12+ months were 1.10 (95% confidence interval, 0.62-1.94), 1.41 (0.79-2.52) and 1.88 (1.05-3.37) with p for trend=0.035. This trend was attenuated somewhat by adjusting for paternal age, and was observed more strongly in offspring of fathers aged 30+ (p=.010). These findings suggest that factors associated with fecundability, either male or female, may contribute to the risk of schizophrenia.

Survey of Neonates in Pomerania (SNiP): a population-based birth study--objectives, design and population coverage

Neonatal health is of major concern to parents, midwives, physicians and society as a whole, yet a prospective population-based birth cohort to collect comprehensive data on multiple issues including medical, social, environmental and genetic aspects remains to be established in Germany. The survey of newborns in Pomerania (SNiP) described in this paper attempts to take up this goal. The objectives of SNiP are to establish (a) a population-based birth cohort providing detailed information about neonatal health, morbidity and mortality, (b) a biobank with newborn DNA and serum from cord blood, placenta tissue samples and DNA obtained from oral mucosal swabs of the mothers, (c) a prospective study design by re-examination of the SNiP population prior to attendance at primary school. From March 2003 until November 2008 all childbearing mothers in a well-defined region in North-Eastern Germany were asked to participate with their newborns. Detailed data on health status of the newborn, pregnancy, medical and family history, socio-economic status and maternal life style were obtained via face-to-face interview, standardised questionnaires and medical records. Placental tissue samples, cord blood plasma and DNA were continuously collected; sampling of maternal DNA from mouth swabs started in 2007. As a result, during the study period n = 6747 births and n = 6828 babies were enrolled. A population coverage of 95% was achieved. The active participation rate was 75%. A non-responder analysis revealed no meaningful selection bias. Thus, SNiP is a population-based, representative study in Germany that is able to describe the health and living conditions of newborns and their families comprehensively. It can contribute to existing knowledge and to similar cohort studies since data are accessible by researchers.

Schizophrenia and birthplace of paternal and maternal grandfather in the Jerusalem perinatal cohort prospective study

Some forms of epigenetic abnormalities transmitted to offspring are manifested in differences in disease incidence that depend on parent-of-origin. To explore whether such phenomena might operate in schizophrenia spectrum disorders, we estimated the relative incidence of these conditions in relation to parent-of-origin by considering the two grandfathers' countries of birth. In a prospective cohort of 88,829 offspring, born in Jerusalem in 1964-76 we identified 637 cases through Israel's psychiatric registry. Relative risks (RR) were estimated for paternal and maternal grandfathers' countries of birth using proportional hazards methods, controlling for parents' ages, low social class and duration of marriage. After adjusting for multiple observations, we found no significant differences between descendants of maternal or paternal grandfathers born in Iraq, Iran, Turkey, Syria, Yemen, Morocco, Algeria, Tunisia, Libya/Egypt, Poland, USSR, Czechoslovakia, Germany or the USA. Those with paternal grandfathers from Romania (RR=1.9, 95% CI=1.3-2.8) or Hungary (1.6, 1.0-2.6) showed an increased incidence; however, those with maternal grandfathers from these countries experienced reduced incidence (RR=0.5, 0.3-0.8 and 0.4, 0.2-0.8). In post-hoc analyses we found that results were similar whether the comparison groups were restricted to descendants of other Europeans or included those from Western Asia and North Africa; and effects of paternal grandfathers from Romania/Hungary were more pronounced in females, while effects of maternal grandfathers from these countries were similar in males and females. These post-hoc "hypothesis-generating" findings lead one to question whether some families with ancestors in Romania or Hungary might carry a variant or mutation at a parentally imprinted locus that is altering susceptibility to schizophrenia. Such a locus, if it exists, might involve the X chromosome.

Anonymous non-response analysis in the ABCD cohort study enabled by probabilistic record linkage

Selective non-response is an important threat to study validity as it can lead to selection bias. The Amsterdam Born Children and their Development study (ABCD-study) is a large cohort study addressing the relationship between life style, psychological conditions, nutrition and sociodemographic background of pregnant women and their children's health. Possible selective non-response and selection bias in the ABCD-study were analysed using national perinatal registry data. ABCD-study data were linked with national perinatal registry data by probabilistic medical record linkage techniques. Differences in the prevalence of relevant risk factors (sociodemographic and care-related factors) and birth outcomes between respondents and non-respondents were tested using Pearson chi-squared tests. Selection bias (i.e. bias in the association between risk factors and specific outcomes) was analysed by regression analysis with and without adjustment for participation status. The ABCD non-respondents were significantly younger, more often non-western, and more often multiparae. Non-respondents entered antenatal care later, were more often under supervision of an obstetrician and had a spontaneous delivery more often. Non-response however, was not significantly associated with preterm birth (odds ratio 1.10; 95% CI 0.93, 1.29) or low birthweight (odds ratio 1.16; 95% CI 0.98, 1.37) after adjustment for sociodemographic risk factors. The associations found between risk factors and adverse pregnancy outcomes were similar for respondents and non-respondents. Anonymised record linkage of cohort study data with national registry data indicated that selective non-response was present in the ABCD-study, but selection bias was acceptably low and did not influence the main study questions.

Incidence of schizophrenia among second-generation immigrants in the jerusalem perinatal cohort

OBJECTIVE

Increased incidence of schizophrenia is observed among some immigrant groups in Europe, with the offspring of immigrants, ie "second-generation" immigrants particularly vulnerable. Few contemporary studies have evaluated the risk of schizophrenia among second-generation immigrants in other parts of the world.

METHODS

We studied the incidence of schizophrenia in relation to parental immigrant status in a population-based cohort of 88 829 offspring born in Jerusalem in 1964-1976. Parental countries of birth were obtained from birth certificates and grouped together as (1) Israel, (2) Other West Asia, (3) North Africa, and (4) Europe and industrialized countries. Cox proportional hazards methods were used in adjusting for sex, parents' ages, maternal education, social class, and birth order.

RESULTS

Linkage with Israel's Psychiatric Registry identified 637 people admitted to psychiatric care facilities with schizophrenia-related diagnoses, before 1998. Incidence of schizophrenia was not increased among second-generation immigrants in this birth cohort, neither overall nor by specific group.

CONCLUSIONS

The difference in risk of schizophrenia among second-generation immigrants in Europe and in this Israeli birth cohort suggests that the nature of the immigration experience may be relevant to risk, including reasons for migration, the nature of entry, and subsequent position in the host country for immigrants and their offspring. Minority status may be of importance as, in later studies, immigrants to Israel from Ethiopia had increased risk of schizophrenia.

Effect of socioeconomic status and parents' education at birth on risk of schizophrenia in offspring

Although it is known that schizophrenia is associated with social class, controversy exists as to the nature of this association. The authors studied the incidence of schizophrenia in relation to social class at birth in a population-based cohort of 88,829 offspring born in Jerusalem in 1964-1976. They constructed a six-point scale to index social class, based on paternal occupation at the time of birth, with each of 108 occupations being ranked by mean education. Cox proportional hazards methods were used in adjusting for sex, parents' ages, duration of marriage and birth order. Linkage with Israel's Psychiatric Registry identified 637 people admitted to psychiatric care facilities with schizophrenia-related diagnoses, before 1998. There was no gradient of risk for schizophrenia associated with social class at birth; however, offspring of fathers in the lowest social class showed a modest increase in risk (adjusted Relative Risk = 1.4; 95% Confidence interval = 1.1-1.8, P = 0.002). These data suggest that in contrast to many other health outcomes, there is not a continuous gradient for increasing schizophrenia with decreasing social class of origin. Instead, a modest increase in risk for schizophrenia was observed only for those born at the bottom of the social ladder.

Cancer risk after exposure to treatments for ovulation induction

Uncertainty continues as to whether treatments for ovulation induction are associated with increased risk of cancer. The authors conducted a long-term population-based historical cohort study of parous women. A total of 15,030 women in the Jerusalem Perinatal Study who gave birth in 1974-1976 participated in a postpartum survey. Cancer incidence through 2004 was analyzed using Cox's proportional hazards models, controlling for age and other covariates. Women who used drugs to induce ovulation (n = 567) had increased risks of cancer at any site (multivariate hazard ratio (HR) = 1.36, 95% confidence interval (CI): 1.06, 1.74). An increased risk of uterine cancer was found among women treated with ovulation-inducing agents (HR = 3.39, 95% CI: 1.28, 8.97), specifically clomiphene (HR = 4.56, 95% CI: 1.56, 13.34). No association was noted between use of ovulation-inducing agents and ovarian cancer (age-adjusted HR = 0.61, 95% CI: 0.08, 4.42). Ovulation induction was associated with a borderline-significant increased risk of breast cancer (multivariate HR = 1.42, 95% CI: 0.99, 2.05). Increased risks were also observed for malignant melanoma and non-Hodgkin lymphoma. These associations appeared stronger among women who waited more than 1 year to conceive. Additional follow-up studies assessing these associations by drug type, dosage, and duration are needed.

Preeclampsia and subsequent risk of cancer: update from the Jerusalem Perinatal Study

OBJECTIVE

The purpose of this study was to examine the association between preeclampsia and cancer incidence.

STUDY DESIGN

The Jerusalem Perinatal Study is a population-based cohort of all births to 41,206 residents of Western Jerusalem from 1964-76. Cancer incidence to 2004 was assessed by linkage of the cohort with the Israel Cancer Registry. Cox's proportional hazards models were constructed to estimate the hazard ratio for cancer among women who had had preeclampsia.

RESULTS

Preeclampsia was associated with a 1.23-fold increased risk of cancer at all sites, a 37% increased risk of breast cancer, and more than a doubling of ovarian cancer risk. Analysis by morphologic condition yielded significantly increased risks for malignancies that were classed as cystic mucinous and serous (relative risk, 1.96; 95% CI, 1.00-3.83) and for ductal, lobular, and medullary carcinomas (relative risk, 1.40; 95% CI, 1.07-1.83). No differential association was observed by sex of offspring.

CONCLUSION

Our study suggests that the previously described protective effect of preeclampsia on cancer is not universal.