Comparison of father-offspring and mother-offspring associations of cardiovascular risk factors: family linkage within the population-based HUNT Study, Norway

Parent-Offspring Associations of Ideal Cardiovascular Health Metrics: Findings From the 2014 to 2021 Korea National Health and Nutrition Examination Survey

BACKGROUND

Studies have reported the strength of cardiovascular health (CVH) metrics in parent-offspring relationships. This study aimed to describe the sex-specific associations between CVH in parents and adult offspring.

METHODS AND RESULTS

This study was conducted on the Korea National Health and Nutrition Examination Survey data set, which analyzed trios of mother-father-child, with the child's age from 20 to 39 years. To use the nature of sampling design, survey weighting was applied to all our analyses. Ideal CVH was defined as a cluster of at least 5 ideal individual CVH metrics. We examined the association between parents and their adult offspring regarding clustering CVH and individual CVH metrics through odds ratios and 95% CIs using multiple logistic regression with standard errors adjusted for within-family clustering. The study included 1267 married couples comprising 748 sons and 819 daughters. After adjusting for household income and offspring's sex, age, education, and alcohol consumption, an offspring with either parent attaining a nonideal CVH was 3.52 times more likely to have nonideal CVH. Fathers' nonideal CVH was significantly positively associated with the daughters' nonideal CVH. Maternal nonideal CVH was significantly positively associated with the son's nonideal CVH. When analyzing individual CVH metrics, ideal status in fathers or mothers reduced the likelihood of their offspring having a nonideal status.

CONCLUSIONS

This cross-sectional study showed positive and differential associations of CVH and its components between parents' and offsprings' nonideal status. Our hypothesis-generating results suggest the relevance of using CVH as a composite indicator in family-centered approaches and heart-health interventions.

Body mass index in parents and their adult offspring: A systematic review and meta-analysis

Obesity may track across generations, due to genetics and shared family environmental factors, or possibly intrauterine programming. However, many studies only assess associations between maternal body mass index (BMI) and offspring BMI in childhood. To determine whether maternal and paternal associations with offspring BMI differ and whether associations persist into adulthood, a systematic review and meta-analysis was done. PubMed, Embase, Web of Science, and Google Scholar (to October 2022) were searched. Observational studies reporting associations between maternal or paternal BMI and adult offspring BMI were included. Offspring BMIs were reported as continuous or categorical measures. Forty-six studies were included in the systematic review. Meta-analyses were conducted using random-effects models. Parental BMI was positively associated with offspring BMI in adulthood. The pooled mother-offspring standardized mean difference (SMD) was 0.23 (95% confidence interval [CI]: 0.20, 0.26), and father-offspring SMD was similar: 0.22 (95% CI: 0.19, 0.25) in adjusted models. Offspring of mothers with overweight or obesity had the same risk of higher BMI as offspring of fathers with overweight or obesity. If these associations are causal, they support interventions targeting all family members, rather than focusing solely on mothers, to obtain a healthy weight development among offspring.

Associations of offspring birthweight and placental weight with subsequent parental coronary heart disease: survival regression using the walker cohort

Low birth weight (BW) is consistently correlated with increased parental risk of subsequent cardiovascular disease, but the links with offspring placental weight (PW) are mostly unexplored. We have investigated the associations between parental coronary heart disease (CHD) and offspring BW and PW using the Walker cohort, a collection of 48,000 birth records from Dundee, Scotland, from the 1950s and 1960s. We linked the medical history of 13,866 mothers and 8,092 fathers to their offspring's records and performed Cox survival analyses modelling maternal and paternal CHD risk by their offspring's BW, PW, and the ratio between both measurements. We identified negative associations between offspring BW and both maternal (hazard ratio [HR]: 0.91, 95% confidence interval [CI]: 0.88-0.95) and paternal (HR: 0.96, 95% CI: 0.93-1.00) CHD risk, the stronger maternal correlation being consistent with previous reports. Offspring PW to BW ratio was positively associated with maternal CHD risk (HR: 1.14, 95% CI: 1.08-1.21), but the associations with paternal CHD were not significant. These analyses provide additional evidence for intergenerational associations between early growth and parental disease, identifying directionally opposed correlations of maternal CHD with offspring BW and PW, and highlight the importance of the placenta as a determinant of early development and adult disease.

Cardiovascular Risk in Pediatrics: A Dynamic Process during the First 1000 Days of Life

The early childhood period, encompassing prenatal and early stages, assumes a pivotal role in shaping cardiovascular risk factors. We conducted a narrative review, presenting a non-systematic summation and analysis of the available literature, focusing on cardiovascular risk from prenatal development to the first 1000 days of life. Elements such as maternal health, genetic predisposition, inadequate fetal nutrition, and rapid postnatal growth contribute to this risk. Specifically, maternal obesity and antibiotic use during pregnancy can influence transgenerational risk factors. Conditions at birth, such as fetal growth restriction and low birth weight, set the stage for potential cardiovascular challenges. To consider cardiovascular risk in early childhood as a dynamic process is useful when adopting a personalized prevention for future healthcare and providing recommendations for management throughout their journey from infancy to early adulthood. A comprehensive approach is paramount in addressing early childhood cardiovascular risks. By targeting critical periods and implementing preventive strategies, healthcare professionals and policymakers can pave the way for improved cardiovascular outcomes. Investing in children's health during their early years holds the key to alleviating the burden of cardiovascular diseases for future generations.

Association of Parental Cardiovascular Health With Disability-Adjusted Life Years in the Offspring: Results From the Framingham Heart Study

BACKGROUND

Disability-adjusted life years (DALYs) are used to evaluate the relative burden of diseases in populations to help set prevention or treatment priorities. The impact of parental cardiovascular health (CVH) on healthy life years lost from cardiovascular disease (CVD) in adult offspring is unknown. We compared parent-offspring CVD DALYs trends over the life course and examined the association of parental CVH with offspring CVD DALYs.

METHODS

Using data from the Framingham Heart Study, 4814 offspring-mother-father trios were matched for age at selected baseline exams. CVH score was computed from the number of CVH metrics attained at recommended levels: poor (0-2), intermediate (3-4), and ideal (5-7). CVD DALYs were defined as the sum of years of life lost and years lived with CVD. Age-sex-standardized life expectancy and disability weights were derived from the actuarial life tables and Global Burden of Disease study, respectively. Multivariable-adjusted linear regression was used to investigate the association of parental CVH with offspring CVD DALYs.

RESULTS

Over an equal 47-year follow-up, parents lost nearly twice the number of CVD DALYs compared to their offspring (23 234 versus 12 217). However, age-adjusted CVD DALYs were higher at younger ages and similar along the life course for parents and offspring. One-unit increase in parental CVH was associated with 5 healthy life months saved in offspring. Offspring of mothers with ideal versus poor CVH had 3 healthy life years saved (β=-3.0 DALYs [95% CI, -5.6 to -0.3]). No statistically significant association was found between paternal CVH categories and offspring CVD DALYs.

CONCLUSIONS

Higher maternal and paternal CVH were associated with increased healthy life years in offspring; however, the association was strongest between mothers and offspring. Investment in CVH promotion along the life course has the potential to reduce the burden of CVD in the current and future generation of adults.

The role of family factors in the association between early adulthood BMI and risk of cardiovascular disease. An intergenerational study of BMI in early adulthood and cardiovascular mortality in parents, aunts and uncles

Background

High body mass index (BMI) in childhood and adolescence is related to cardiovascular disease (CVD). Causality is not established because common genetic or early life socioeconomic factors (family factors) may explain this relationship. We aimed to study the role of family factors in the association between BMI and CVD by investigating if early adulthood BMI in conscripts and CVD mortality in their parents/aunts/uncles are related.

Methods

Data from the Armed Forces Personnel Database (including height and weight among conscripts) were linked with data from the Norwegian Population Registry, generational data from the Norwegian Family Based Life Course Study, the National Educational Registry and the Cause of Death Registry using unique personal identification numbers. The study sample (N=369 464) was Norwegian males born 1967-1993, who could be linked to both parents and at least one maternal and one paternal aunt or uncle. Subsamples were identified as conscripts whose parents/aunts/uncles had data on cardiovascular risk factors available from Norwegian health surveys. Cox proportional hazards regression models were used to estimate hazard ratios (HR) of CVD mortality in the parental generation according to BMI categories of conscripts.

Results

Parents of conscripts with obesity or overweight had a higher hazard of CVD death (fathers HR obese: 1.99 (1.79,2.21), overweight: 1.33 (1.24,1.42) mothers HR obese: 1.65 (1.32,2.07), overweight: 1.23 (1.07,1.42)) than parents of normal- or underweight conscripts. Aunts and uncles of conscripts with obesity and overweight had an elevated hazard of CVD death, but less so than parents. Adjustment for CVD risk factors attenuated the results in parents, aunts and uncles.

Conclusions

Family factors may impact the relationship between early adulthood overweight and CVD in parents. These can be genes with impact on BMI over generations and genes with a pleiotropic effect on both obesity and CVD, as well as shared environment over generations.

Predictive value of women's weight trajectories in determining familial cardiovascular disorders: a family-based longitudinal study

Considering the dynamic nature of body mass index (BMI) and its importance in determining cardiovascular risks, this study aimed to investigate the life-course trajectory pattern of women’s BMI and its association with cardiovascular risk factors. A total of 1356 couples with 2976 children were recruited and followed up for an average period of 20 years. Latent growth curve modeling was applied to determine women's BMI trajectories; logistic regression was used to investigate the associations between trajectory patterns and cardiovascular risk factors, including hypertension (HTN), dyslipidemia, diabetes mellitus (DM), and obesity. Women were classified into three trajectories, including normal, stage 1 obesity, and stage 2 obesity. Compared to women’s in the normal trajectory group, those in obesity trajectories had higher odds ratios for HTN, DM, and dyslipidemia. Men with obese spouses showed a higher rate of HTN 1.54 (95% CI 1.05–2.25) and DM 1.55; (95% CI 1.00–2.44). The odds of men’s obesity were higher in obese spouses (OR 1.70; 95% CI 1.10–2.62). Offspring of stage 2 obese (OR 2.39; 95% CI 1.67–3.44) and stage 1 obese (OR 4.81; 95% CI 3.16–7.34) mothers were more likely to be obese. Our findings emphasized paying more attention to women with excessive weight to promote familial cardiovascular health in the communities.

Beneficial intergenerational effects of exercise on brain and cognition: a multilevel meta-analysis of mean and variance

Physical exercise not only helps to improve physical health but can also enhance brain development and cognition. Recent reports on parental (both maternal and paternal) effects raise the possibility that parental exercise may provide benefits to offspring through intergenerational inheritance. However, the general magnitude and consistency of parental exercise effects on offspring is still controversial. Additionally, empirical research has long overlooked an important aspect of exercise: its effects on variability in neurodevelopmental and cognitive traits. Here, we compiled data from 52 studies involving 4786 rodents (412 effect sizes) to quantify the intergenerational transmission of exercise effects on brain and cognition. Using a multilevel meta-analytic approach, we found that, overall, parental exercise showed a tendency for increasing their offspring's brain structure by 12.7% (albeit statistically non-significant) probably via significantly facilitating neurogenesis (16.5%). Such changes in neural anatomy go in hand with a significant 20.8% improvement in neurobehaviour (improved learning and memory, and reduced anxiety). Moreover, we found parental exercise significantly reduces inter-individual differences (i.e. reduced variance in the treatment group) in progeny's neurobehaviour by 10.2% (coefficient of variation ratio, lnCVR), suggesting the existence of an individual by intervention interaction. The positive effects of exercise are modulated by several covariates (i.e. moderators), such as the exercised parent's sex, offspring's sex, and age, mode of exercise, and exercise timing. In particular, parental forced exercise is more efficient than voluntary exercise at significantly improving offspring neurobehaviour (26.0%) and reducing its variability (14.2%). We observed larger effects when parental exercise started before pregnancy. However, exercising only during pregnancy also had positive effects. Mechanistically, exercise significantly upregulated brain-derived neurotrophic factor (BDNF) by 28.9%, vascular endothelial growth factor (VEGF) by 35.8%, and significantly decreased hippocampal DNA methylation by 3.5%, suggesting that brain growth factor cascades and epigenetic modifications can moderate the transmission of parental exercise effects. Collectively, by coupling mean with variance effects, our analyses draw a more integrated picture of the benefits that parental exercise has on offspring: not only does it improve offspring brain development and cognitive performance, but it also reduces inter-individual differences in cognition-related traits. We advocate that meta-analysis of variation together with the mean of a trait provides novel insights for old controversies as well as emerging new questions, opening up a new era for generating variance-based hypotheses.

Identification and Estimation of Causal Effects Using a Negative-Control Exposure in Time-Series Studies With Applications to Environmental Epidemiology

The initial aim of environmental epidemiology is to estimate the causal effects of environmental exposures on health outcomes. However, due to lack of enough covariates in most environmental data sets, current methods without enough adjustments for confounders inevitably lead to residual confounding. We propose a negative-control exposure based on a time-series studies (NCE-TS) model to effectively eliminate unobserved confounders using an after-outcome exposure as a negative-control exposure. We show that the causal effect is identifiable and can be estimated by the NCE-TS for continuous and categorical outcomes. Simulation studies indicate unbiased estimation by the NCE-TS model. The potential of NCE-TS is illustrated by 2 challenging applications: We found that living in areas with higher levels of surrounding greenness over 6 months was associated with less risk of stroke-specific mortality, based on the Shandong Ecological Health Cohort during January 1, 2010, to December 31, 2018. In addition, we found that the widely established negative association between temperature and cancer risks was actually caused by numbers of unobserved confounders, according to the Global Open Database from 2003-2012. The proposed NCE-TS model is implemented in an R package (R Foundation for Statistical Computing, Vienna, Austria) called NCETS, freely available on GitHub.

Parental cardiovascular health predicts time to onset of cardiovascular disease in offspring

BACKGROUND

Cardiovascular disease (CVD) risk factors are transmitted from parents to children. We prospectively examined the association between parental cardiovascular health (CVH) and time to onset of CVD in the offspring.

METHODS AND RESULTS

The study consisted of a total of 5967 offspring-mother-father trios derived from the Framingham Heart Study. Cardiovascular health score was defined using the seven American Heart Association's CVH metrics attained at ideal levels: poor (0-2), intermediate (3-4), and ideal CVH (5-7). Multivariable-adjusted Cox proportional hazards regression models, Kaplan-Meier plots, and Irwin's restricted mean were used to examine the association and sex-specific differences between parental CVH and offspring's CVD-free survival. In a total of 71 974 person-years of follow-up among the offspring, 718 incident CVD events occurred. The overall CVD incidence rate was 10 per 1000 person-years [95% confidence interval (CI) 9.3-10.7]. Offspring of mothers with ideal CVH lived 9 more years free of CVD than offspring of mothers with poor CVH (P < 0.001). Maternal poor CVH was associated with twice as high hazard of early onset of CVD compared with maternal ideal CVH (adjusted Hazard Ratio 2.09, 95% CI 1.50-2.92). No statistically significant association was observed in the hazards of CVD-free survival by paternal CVH categories.

CONCLUSIONS

We found that offspring of parents with ideal CVH had a greater CVD-free survival. Maternal CVH was a more robust predictor of offspring's CVD-free survival than paternal CVH, underscoring the need for clinical and policy interventions that involve mothers to break the intergenerational cycle of CVD-related morbidity and mortality.

Birthweight in offspring and cardiovascular mortality in their parents, aunts and uncles: a family-based cohort study of 1.35 million births

Background

A link between suboptimal fetal growth and higher risk of cardiovascular disease (CVD) is well documented. It has been difficult to assess the contribution of environmental versus genetic factors to the association, as these factors are closely connected in nuclear families. We investigated the association between offspring birthweight and CVD mortality in parents, aunts and uncles, and examined whether these associations are explained by CVD risk factors.

Methods

We linked Norwegian data from the Medical Birth Registry, the Cause of Death Registry and cardiovascular surveys. A total of 1 353 956 births (1967–2012) were linked to parents and one maternal and one paternal aunt/uncle. Offspring birthweight and CVD mortality association among all relationships was assessed by hazard ratios (HR) from Cox regressions. The influence of CVD risk factors on the associations was examined in a subgroup.

Results

Offspring birthweight was inversely associated with CVD mortality among parents and aunts/uncles. HR of CVD mortality for one standard deviation (SD) increase in offspring birthweight was 0.72 (0.69–0.75) in mothers and 0.89 (0.86–0.92) in fathers. In aunts/uncles, the HRs were between 0.90 (0.86–0.95) and 0.93 (0.91–0.95). Adjustment for CVD risk factors in a subgroup attenuated all the associations.

Conclusions

Birthweight was associated with increased risk of CVD in parents and in aunts/uncles. These associations were largely explained by CVD risk factors. Our findings suggest that associations between offspring birthweight and CVD in adult relatives involve both behavioural variables (especially smoking) and shared genetics relating to established CVD risk factors.

Temporal Trends and Familial Clustering of Ideal Cardiovascular Health in Parents and Offspring Over the Life Course: An Investigation Using The Framingham Heart Study

Background

Evidence suggests familial aggregation and intergenerational associations for individual cardiovascular health (CVH) metrics. Over a 53‐year life course, we examined trends and association of CVH between parents and their offspring at similar mean ages.

Methods and Results

We conducted a series of cross‐sectional analyses of the FHS (Framingham Heart Study). Parent‐offspring pairs were assessed at exams where their mean age distributions were similar. Ideal CVH was defined using 5 CVH metrics: blood pressure (<120/<80 mm Hg), fasting blood glucose (<100 mg/dL), blood cholesterol (<200 mg/dL), body mass index (<25 kg/m²), and non‐smoking. Joinpoint regression and Chi‐squared test were used to assess linear trend; proportional‐odds regression was used to examine the association between parents and offspring CVH. A total of 2637 parents were paired with 3119 biological offspring throughout 6 exam cycles. Similar patterns of declining ideal CVH with advancing age were observed in parents and offspring. Small proportions of parents (4%) and offspring (17%) achieved 5 CVH metrics at ideal levels (P‐trend <0.001). Offspring of parents with poor CVH had more than twice the odds of having poor CVH (pooled odds ratio, 2.59; 95% CI, 1.98–3.40). Over time, elevated glucose levels and obesity doubled among the offspring and were the main drivers for declining ideal CVH trends.

Conclusions

Parental CVH was positively associated with offspring CVH. However, intergenerational CVH gains from declining smoking rates, cholesterol, and blood pressure were offset by rising offspring obesity and elevated glucose levels. This suggests an intergenerational phenotypic shift of risk factors and the need for a family‐centered approach to cardiovascular care.

Parental Multisite Chronic Pain and the Risk of Adult Offspring Developing Additional Chronic Pain Sites: Family-Linkage Data From the Norwegian HUNT Study

We investigated if parental multisite chronic pain increases the risk of adult offspring developing additional chronic pain sites, and if offspring body mass index (BMI) and leisure time physical activity modify this association. We used longitudinal data on 7,654 offspring linked with their parents who participated in the population-based HUNT Study (Norway) in 1995 to 1997 and 2006 to 2008. Logistic regression was used to estimate odds ratios (ORs) with 95% confidence interval (CI). One-third of offspring (n = 2,573) developed additional chronic pain sites. Having both parents with 1-2 chronic pain sites increased the risk of developing additional pain sites compared to having parents free of chronic pain (OR = 1.33; 95% CI 1.05-1.68), with larger effects observed when both parents had ≥3 chronic pain sites (OR = 1.46; 95% CI 1.17-1.82). These associations were largely driven by maternal pain, that is, there was no association between paternal chronic pain and risk of additional pain sites in offspring. The parent-offspring transfer of additional pain sites (when both parents had ≥3 pain sites) strengthened when offspring were obese (OR = 2.56; 95% CI 1.75-3.75) or physically inactive (OR = 1.73; 95% CI 1.33-2.27). In conclusion, parental multisite chronic pain increases the risk of offspring developing additional chronic pain sites, particularly those with obesity or inactivity. PERSPECTIVE: This longitudinal analysis investigated the parent-offspring transmission of multisite chronic pain, and whether lifestyle behaviors in offspring modify this association. The findings suggest that having parents with multisite chronic pain increases the risk of offspring developing additional chronic pain sites, particularly if offspring are obese or inactive.

Cardiovascular Risk Factors Track From Mother to Child

Background

Cardiovascular risk factors can track from mother to child by several pathways: pregnancy complications, genetic inheritance, and shared environmental risk factors after pregnancy. The degree of tracking, and to which extent this is influenced by these pathways, is unknown. We hypothesized that cardiovascular risk factors track from mother to child regardless of pregnancy complications and environmental risk factors. We determined the degree of tracking between maternal and offspring micro‐ and macrovascular cardiovascular risk factors after pregnancy and the extent to which this is influenced by pregnancy complications and shared environmental risk factors.

Methods and Results

We included 5624 mother‐offspring pairs from The Generation R Study, an ongoing prospective, population‐based birth cohort. Information on pregnancy complications (preeclampsia, small for gestational age, and preterm birth) was obtained through hospital charts. Mother‐offspring associations were assessed 6 years after pregnancy (central retinal arteriolar and venular calibers, body mass index, blood pressure, left atrial diameter, aortic root diameter, left ventricular mass, fractional shortening, and pulse wave velocity) and 9 years after pregnancy (body mass index and blood pressure). We observed that worse cardiovascular parameters in mothers were associated with worse cardiovascular parameters in their offspring 6 and 9 years after pregnancy (P<0.001). Results were similar when mother‐offspring pairs with a previous pregnancy complication were excluded.

Conclusions

Six and 9 years after pregnancy, an adverse cardiovascular profile in mothers is strongly associated with an adverse cardiovascular profile in their offspring. Results were not attenuated by environmental exposures or a previous pregnancy complication. This supports the hypothesis that cardiovascular risk factors (micro‐ and macrovascular) track from mother to child, regardless of the course of pregnancy.

Parental Renovascular Hypertension-Induced Autonomic Dysfunction in Male Offspring Is Improved by Prenatal or Postnatal Treatment With Hydrogen Sulfide

Increasing evidence indicates there is a strong association between parental health during pregnancy and incidence of cardiovascular disease in adult offspring. Recently, hydrogen sulfide (H₂S) has been demonstrated to be a powerful vasodilator of the placental vasculature, improving intrauterine growth restriction. In this study, we investigated whether parental hypertension induces autonomic dysfunction in male adult offspring, and the H₂S mechanism underlying this autonomic dysfunction. 2-kidney-1-clip method was employed to induce parental hypertension during pregnancy and lactation in rats. Basal blood pressure (BP) and autonomic function of male offspring in adulthood was evaluated. Additionally, either maternal hypertensive dams or their male offspring after weaning were treated with H₂S to determine improving effects of H₂S on autonomic dysfunction. The BP was significantly increased in male offspring of renovascular hypertensive dams when compared to that in offspring of normotensive dams. The offspring of renovascular hypertensive dams also exhibited blunted baroreflex sensitivity, increased sympathetic effect and sympathetic tonus. Western blotting analysis revealed downregulation of endogenous H₂S catalyzed enzyme and upregulation of angiotensin Ang II type 1 receptor (AT1R) pathway in the nucleus tractus solitarius and rostral ventrolateral medulla, two hindbrain nuclei involved in BP and autonomic regulation, in these offspring. Either prenatal or postnatal treatment with H₂S improved the adverse effects. The results suggest that parental hypertension results in elevated BP and autonomic dysfunction in adult male offspring through activation of AT1R pathway and inhibition of endogenous H₂S production in the brain.

Variation of all-cause and cause-specific mortality with body mass index in one million Swedish parent-son pairs: An instrumental variable analysis

BACKGROUND

High body mass index (BMI) is associated with mortality, but the pervasive problem of confounding and reverse causality in observational studies limits inference about the direction and magnitude of causal effects. We aimed to obtain estimates of the causal association of BMI with all-cause and cause-specific mortality.

METHODS AND FINDINGS

In a record-linked, intergenerational prospective study from the general population of Sweden, we used two-sample instrumental variable (IV) analysis with data from 996,898 fathers (282,407 deaths) and 1,013,083 mothers (153,043 deaths) and their sons followed up from January 1, 1961, until December 31, 2004. Sons' BMI was used as the instrument for parents' BMI to compute hazard ratios (HRs) for risk of mortality per standard deviation (SD) higher parents' BMI. Using offspring exposure as an instrument for parents' exposure is unlikely to be affected by reverse causality (an important source of bias in this context) and reduces confounding. IV analyses supported causal associations between higher BMI and greater risk of all-cause mortality (HR [95% confidence interval (CI)] per SD higher fathers' BMI: 1.29 [1.26-1.31] and mothers' BMI: 1.39 [1.35-1.42]) and overall cancer mortality (HR per SD higher fathers' BMI: 1.20 [1.16-1.24] and mothers' BMI: 1.29 [1.24-1.34]), including 9 site-specific cancers in men (bladder, colorectum, gallbladder, kidney, liver, lung, lymphatic system, pancreas, and stomach) and 11 site-specific cancers in women (gallbladder, kidney, liver, lung, lymphatic system, ovaries, pancreas, stomach, uterus, cervix, and endometrium). There was evidence supporting causal associations between higher BMI in mothers and greater risk of mortality from kidney disease (HR: 2.17 [1.68-2.81]) and lower risk of mortality from suicide (HR: 0.77 [0.65-0.90]). In both sexes, there was evidence supporting causal associations between higher BMI and mortality from cardiovascular diseases (CVDs), stroke, diabetes, and respiratory diseases. We were unable to test the association between sons' and mothers' BMIs (as mothers' data were unavailable) or whether the instrument was independent of unmeasured or residual confounding; however, the associations between parents' mortality and sons' BMI were negligibly influenced by adjustment for available confounders.

CONCLUSIONS

Consistent with previous large-scale meta-analyses and reviews, results supported the causal role of higher BMI in increasing the risk of several common causes of death, including cancers with increasing global incidence. We also found positive effects of BMI on mortality from respiratory disease, prostate cancer, and lung cancer, which has been inconsistently reported in the literature, suggesting that the causal role of higher BMI in mortality from these diseases may be underestimated. Furthermore, we expect different patterns of bias in the current observational and IV analyses; therefore, the similarities between our findings from both methods increases confidence in the results. These findings support efforts to understand the mechanisms underpinning these effects to inform targeted interventions and develop population-based strategies to reduce rising obesity levels for disease prevention.

Vascular function and stiffness: population epidemiology and concordance in Australian children aged 11-12 years and their parents

OBJECTIVES

To describe the epidemiology and parent-child concordance of vascular function in a population-based sample of Australian parent-child dyads at child age 11-12 years.

DESIGN

Cross-sectional study (Child Health CheckPoint), nested within a prospective cohort study, the Longitudinal Study of Australian Children (LSAC).

SETTING

Assessment centres in seven major Australian cities and eight regional towns or home visits, February 2015-March 2016.

PARTICIPANTS

Of all participating CheckPoint families (n=1874), 1840 children (49% girls) and 1802 parents (88% mothers) provided vascular function data. Survey weights and methods were applied to account for LSAC's complex sample design and clustering within postcodes and strata.

OUTCOME MEASURES

The SphygmoCor XCEL assessed vascular function, generating estimates of brachial and central systolic blood pressure and diastolic blood pressure, central pulse pressure, augmentation index and carotid-femoral pulse wave velocity. Pearson's correlation coefficients and multivariable linear regression models estimated parent-child concordance.

RESULTS

Hypertension was present in 3.9% of children and 9.0% of parents. Mean child and parent values for augmentation index were 4.5% (SD 11.6) and 21.3% (SD 12.3), respectively, and those for carotid-femoral pulse wave velocity were 4.48 m/s (SD 0.59) and 6.85 m/s (SD 1.14), respectively. Parent-child correlation for brachial systolic blood pressure was 0.20 (95% CI 0.15 to 0.24), brachial diastolic blood pressure 0.21 (95% CI 0.16 to 0.26), central systolic blood pressure 0.21 (95% CI 0.16 to 0.25), central diastolic blood pressure 0.21 (95% CI0.17 to 0.26), central pulse pressure 0.19 (95% CI 0.14 to 0.24), augmentation index 0.28 (95% CI 0.23 to 0.32) and pulse wave velocity 0.22 (95% CI 0.18 to 0.27).

CONCLUSIONS

We report Australian values for traditional and more novel vascular function markers, providing a reference for future population studies. Cross-generational concordance in multiple vascular function markers is already established by age 11-12 years, with mechanisms of heritability remaining to be explored.

Parent's Cardiorespiratory Fitness, Body Mass, and Chronic Disease Status Is Associated with Metabolic Syndrome in Young Adults: A Preliminary Study

We sought to determine if there was an intergenerational association between parental weight, cardiorespiratory fitness (CRF), and disease status, with the prevalence of metabolic syndrome (MetSyn) in their young adult offspring. Young adults (n = 270, 21 ± 1 years, 53.3% female) were assessed for MetSyn and self-reported parent’s CRF, body mass status, and disease status. MetSyn was present in 11.9% of participants, 27.4% had one or two components, and 58.5% had no components. A significantly higher percentage (93.9%) of young adults with MetSyn identified at least one parent as being overweight or obese, 84.8% reported low parental CRF and 87.9% reported a parent with disease (all p < 0.017). MetSyn in offspring is more likely when parents are perceived to have low CRF, increased body mass, and a diagnosis of disease. Evaluating the offspring of people with low CRF, elevated body mass, or who have a history of cardiovascular disease (CVD) or diabetes should be considered to promote early identification and treatment of young adults to reduce future premature CVD in these at-risk individuals.

Negative control exposure studies in the presence of measurement error: implications for attempted effect estimate calibration

Background

Negative control exposure studies are increasingly being used in epidemiological studies to strengthen causal inference regarding an exposure-outcome association when unobserved confounding is thought to be present. Negative control exposure studies contrast the magnitude of association of the negative control, which has no causal effect on the outcome but is associated with the unmeasured confounders in the same way as the exposure, with the magnitude of the association of the exposure with the outcome. A markedly larger effect of the exposure on the outcome than the negative control on the outcome strengthens inference that the exposure has a causal effect on the outcome.

Methods

We investigate the effect of measurement error in the exposure and negative control variables on the results obtained from a negative control exposure study. We do this in models with continuous and binary exposure and negative control variables using analysis of the bias of the estimated coefficients and Monte Carlo simulations.

Results

Our results show that measurement error in either the exposure or negative control variables can bias the estimated results from the negative control exposure study.

Conclusions

Measurement error is common in the variables used in epidemiological studies; these results show that negative control exposure studies cannot be used to precisely determine the size of the effect of the exposure variable, or adequately adjust for unobserved confounding; however, they can be used as part of a body of evidence to aid inference as to whether a causal effect of the exposure on the outcome is present.

Parental chronic widespread pain and the association with chronic widespread pain in adult offspring: Family-linkage data from the Norwegian HUNT Study

BACKGROUND

Individuals experiencing chronic widespread pain (CWP) have greater disability and poorer quality of life compared to those with other chronic painful conditions; although research identifying risk factors for CWP is lacking. We aimed to investigate whether parental CWP increases the risk of offspring CWP, and if offspring body mass index (BMI) and leisure time physical activity modify this association.

METHODS

We included 6589 parent-offspring trios participating in the Norwegian HUNT Study in 1995-1997 and 2006-2008. Logistic regression was used to calculate adjusted odd ratios (ORs) (95% confidence intervals, CIs) as estimates of relative risk for offspring CWP. We analysed the joint effect of parental CWP and offspring BMI or leisure time physical activity on offspring risk of CWP and calculated the relative excess risk due to interaction (RERI).

RESULTS

In total, 886 (13.5%) offspring developed CWP during follow-up. Having one (OR = 1.23, 95% CI, 1.05-1.44) or both parents with CWP (OR = 1.89, 95% CI, 1.50-2.38) increased the risk of offspring CWP. In analyses of joint effects, ORs were 1.84 (95% CI, 1.31-2.56) and 3.35 (95% CI, 1.94-5.77) in normal weight and obese offspring, respectively, when both parents had CWP. The estimate of RERI suggested some synergistic effect (RERI = 1.19, 95% CI, -0.68 to 3.05), although precision was low. Risk of CWP was similar in active (OR = 2.05, 95% CI, 1.56-2.70) and inactive (OR = 1.96, 95% CI, 1.31-2.91) offspring when both parents had CWP.

CONCLUSION

Parental CWP increases the risk of CWP in adult offspring, particularly if both parents have CWP and offspring are obese. This highlights a familial predisposition for CWP and an important target group for preventive measures.

SIGNIFICANCE

The parent-offspring transmission of CWP is stronger in obese offspring (particularly when both parents have CWP). This study is the first to investigate the interaction between modifiable lifestyle factors, familial factors and CWP.

Association of parental obesity with cardiometabolic risk factors in their children: The CASPIAN-V study

BACKGROUND

The family environment has a crucial role in the development of childhood obesity and related cardiometabolic disorders. This study aims to investigate the association of parental obesity and cardiometabolic risk factors in their children.

METHODS

This multicentric cross-sectional study was performed on 14400 students (aged 7-18 years) and one of their parents. Students were recruited by multistage, stratified cluster sampling from urban and rural areas of 30 provinces of Iran. Fasting venous blood was obtained from a random sample of 4200 students. Demographic, anthropometric and clinical variables were collected.

RESULTS

Data of 14002 students and results of blood samples of 3483 of them were complete and included in the current study. The prevalence of obesity in children, fathers, and mothers was 11.4%, 10.6%, and 24.2%, respectively. In students, the most commonly observed metabolic abnormality was low HDL-C (29.5%); the prevalence of metabolic syndrome and dyslipidemia was 5% and 55.7%, respectively. Significant correlations were observed between the body mass index (BMI) and waist circumference of parents and weight, height, BMI, and waist circumference, as well as systolic and diastolic blood pressure (BP) of their children (P< 0.05). In the multivariate model, the risk of excess weight (OR: 1.30, 95%CI: 1.17-1.44), obesity (OR: 1.36, 95%CI: 1.18-1.59), abdominal obesity (OR: 1.16, 95%CI: 1.05-1.29) and elevated BP (OR: 1.17, 95%CI: 1.04-1.31) were higher in those students whose parents had excess weight compared with other students. Parental obesity did not have significant association with metabolic syndrome and dyslipidemia in their children.

CONCLUSIONS

Parental history of obesity could be used as a practical approach for the early preventive measures and identification of children at risk of cardiometabolic complications.

Offspring birth weight and cardiovascular mortality among parents: the role of cardiovascular risk factors

An inverse association between offspring birth weight (BW) and higher risk of parental cardiovascular disease (CVD) mortality and morbidity has been reported. Shared environmental, genetic and intrauterine factors may be responsible for explaining these associations. We studied the role of parental CVD risk factors in the association between offspring BW and CVD mortality among mothers and fathers. All births registered in Medical Birth Registry Norway (1967–2012) were linked to three health surveys, National Educational Registry and Cause of Death Registry. Number of births with information of parental CVD risk factors available for the analyses was 1,006,557 (520,670 for mothers and 485,887 for fathers). Cox proportional hazards regression models were used, following CVD deaths in parents from 1974 to 2012. An inverse association between offspring BW and CVD mortality was observed among both parents: hazard ratio 1.60 (1.44–1.75) for mothers and 1.16 (1.10–1.23) for fathers. Among mothers, adjustment for smoking, triglycerides and diabetes reduced the risk to 1.36 (1.25–1.52), 1.57 (1.43–1.73) and 1.58 (1.43–1.79), respectively. Adjustment for diastolic blood pressure (DBP) and systolic blood pressure (SBP) both reduced the risk to 1.53 (1.37–1.66). Among fathers, adjustments for smoking, DBP, SBP reduced the risk to 1.08 (1.02–1.15), 1.13 (1.06–1.19) and 1.14 (1.08–1.22), respectively. Triglycerides and diabetes both reduced the risk to 1.15 (1.09–1.12). Our results indicate that shared environmental factors might be important in the association. A stronger association in mothers suggest that intrauterine factors also are at play.

Confounding by ill health in the observed association between BMI and mortality: evidence from the HUNT Study using offspring BMI as an instrument

Background

The observational association between mortality and body mass index (BMI) is U-shaped, leading to highly publicized suggestions that moderate overweight is beneficial to health. However, it is unclear whether elevated mortality is caused by low BMI or if the association is confounded, for example by concurrent ill health.

Methods

Using HUNT, a Norwegian prospective study, 32 452 mother-offspring and 27 747 father-offspring pairs were followed up to 2009. Conventional hazard ratios for parental mortality per standard deviation of BMI were estimated using Cox regression adjusted for behavioural and socioeconomic factors. To estimate hazard ratios with reduced susceptibility to confounding, particularly from concurrent ill health, the BMI of parents’ offspring was used as an instrumental variable for parents’ own BMI. The shape of mortality-BMI associations was assessed using cubic splines.

Results

There were 18 365 parental deaths during follow-up. Conventional associations of mortality from all-causes, cardiovascular disease and cancer with parents’ own BMI were substantially nonlinear, with elevated mortality at both extremes and minima at 21–25 kg m⁻². Equivalent associations with offspring BMI were positive and there was no evidence of elevated parental mortality at low offspring BMI. The linear instrumental variable hazard ratio for all-cause mortality per standard deviation increase in BMI was 1.18 (95% confidence interval: 1.10, 1.26), compared with 1.05 (1.03, 1.06) in the conventional analysis.

Conclusions

Elevated mortality rates at high BMI appear causal, whereas excess mortality at low BMI is likely exaggerated by confounding by factors including concurrent ill health. Conventional studies probably underestimate the adverse population health consequences of overweight.

Maternal Renovascular Hypertensive Rats Treatment With Hydrogen Sulfide Increased the Methylation of AT1b Gene in Offspring

BACKGROUND

A large number of studies have shown hypertension of offspring in adulthood is related to parental health during pregnancy. Hydrogen sulfide (H2S) could relax placental vasculature and improve intrauterine growth restriction. In the present study, we want to observe the effect of H2S on the fetal programming of renovascular hypertension, a rat model of secondary hypertension.

METHODS

Renovascular hypertension was induced by 2-kidney-1-clip, their adult pups were used to evaluate basal blood pressure. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured noninvasively by tail-cuff plethysmography in conscious offspring; HE staining was used to observe morphology of kidney; the protein expression of angiotensin II receptor 1 (AT1R) tested by western blot; methylation of angiotensin II receptor 1b (AT1b) gene used pBLUE-T-cloning to check.

RESULTS

The SBP and DBP in the offspring of renovascular hypertensive dams were higher than those in control group. Moreover, interstitial inflammatory infiltration was significant in the kidney and the protein expression of AT1R was also increased in the offspring of renovascular hypertensive dams. Conversely, methylation of AT1b promoter (U01033 277-1611) decreased in the first 3 CG sites. Either prenatal or postnatal treatment with H2S could increase the methylation of AT1b and downregulate AT1R expression then improve the blood pressure.

CONCLUSION

These results suggested that parental secondary hypertension-induced kidney damage that elevated basal blood pressure in adult offspring. Prenatal or postnatal administration with H2S induced improved effect accompanied by an increased methylation of AT1b gene then downregulated protein of AT1R in offspring.

Anthropometric and cardiometabolic risk factors in parents and child obesity in Segamat, Malaysia

Background

There is little evidence regarding risk factors for child obesity in Asian populations, including the role of parental anthropometric and cardiometabolic risk factors. We examined the relation between parental risk factors and child obesity in a Malaysian population.

Methods

We used data from health and demographic surveillance conducted by the South East Asia Community Observatory in Segamat, Malaysia. Analyses included 9207 individuals (4806 children, 2570 mothers and 1831 fathers). Child obesity was defined based on the World Health Organization 2007 reference. We assessed the relation between parental anthropometric (overweight, obesity and central obesity) and cardiometabolic (systolic hypertension, diastolic hypertension and hyperglycaemia) risk factors and child obesity, using mixed effects Poisson regression models with robust standard errors.

Results

We found a high burden of overweight and obesity among children in this population (30% overweight or obese). Children of one or more obese parents had a 2-fold greater risk of being obese compared with children of non-obese parents. Sequential adjustment for parental and child characteristics did not materially affect estimates (fully adjusted relative risk for obesity in both parents: 2.39, 95% confidence interval: 1.82, 3.10, P < 0.001; P for trend < 0.001). These associations were not modified by parental or child sex. We found no consistent evidence for associations between parental cardiometabolic risk factors and child obesity.

Conclusions

Parental obesity was strongly associated with child obesity in this population. Further exploration of the behavioural and environmental drivers of these associations may help inform strategies addressing child obesity in Asia.

Paternal programming of offspring cardiometabolic diseases in later life

Early - intrauterine - environmental factors are linked to the development of cardiovascular disease in later life. Traditionally, these factors are considered to be maternal factors such as maternal under and overnutrition, exposure to toxins, lack of micronutrients, and stress during pregnancy. However, in the recent years, it became obvious that also paternal environmental factors before conception and during sperm development determine the health of the offspring in later life. We will first describe clinical observational studies providing evidence for paternal programming of adulthood diseases in progeny. Next, we describe key animal studies proving this relationship, followed by a detailed analysis of our current understanding of the underlying molecular mechanisms of paternal programming. Alterations of noncoding sperm micro-RNAs, histone acetylation, and targeted as well as global DNA methylation seem to be in particular involved in paternal programming of offspring's diseases in later life.

Using Genetic Variation to Explore the Causal Effect of Maternal Pregnancy Adiposity on Future Offspring Adiposity: A Mendelian Randomisation Study

BACKGROUND

It has been suggested that greater maternal adiposity during pregnancy affects lifelong risk of offspring fatness via intrauterine mechanisms. Our aim was to use Mendelian randomisation (MR) to investigate the causal effect of intrauterine exposure to greater maternal body mass index (BMI) on offspring BMI and fat mass from childhood to early adulthood.

METHODS AND FINDINGS

We used maternal genetic variants as instrumental variables (IVs) to test the causal effect of maternal BMI in pregnancy on offspring fatness (BMI and dual-energy X-ray absorptiometry [DXA] determined fat mass index [FMI]) in a MR approach. This was investigated, with repeat measurements, from ages 7 to 18 in the Avon Longitudinal Study of Parents and Children (ALSPAC; n = 2,521 to 3,720 for different ages). We then sought to replicate findings with results for BMI at age 6 in Generation R (n = 2,337 for replication sample; n = 6,057 for total pooled sample). In confounder-adjusted multivariable regression in ALSPAC, a 1 standard deviation (SD, equivalent of 3.7 kg/m2) increase in maternal BMI was associated with a 0.25 SD (95% CI 0.21-0.29) increase in offspring BMI at age 7, with similar results at later ages and when FMI was used as the outcome. A weighted genetic risk score was generated from 32 genetic variants robustly associated with BMI (minimum F-statistic = 45 in ALSPAC). The MR results using this genetic risk score as an IV in ALSPAC were close to the null at all ages (e.g., 0.04 SD (95% CI -0.21-0.30) at age 7 and 0.03 SD (95% CI -0.26-0.32) at age 18 per SD increase in maternal BMI), which was similar when a 97 variant generic risk score was used in ALSPAC. When findings from age 7 in ALSPAC were meta-analysed with those from age 6 in Generation R, the pooled confounder-adjusted multivariable regression association was 0.22 SD (95% CI 0.19-0.25) per SD increase in maternal BMI and the pooled MR effect (pooling the 97 variant score results from ALSPAC with the 32 variant score results from Generation R) was 0.05 SD (95%CI -0.11-0.21) per SD increase in maternal BMI (p-value for difference between the two results = 0.05). A number of sensitivity analyses exploring violation of the MR results supported our main findings. However, power was limited for some of the sensitivity tests and further studies with relevant data on maternal, offspring, and paternal genotype are required to obtain more precise (and unbiased) causal estimates.

CONCLUSIONS

Our findings provide little evidence to support a strong causal intrauterine effect of incrementally greater maternal BMI resulting in greater offspring adiposity.

Paternal High Fat Diet in Rats Leads to Renal Accumulation of Lipid and Tubular Changes in Adult Offspring

Along with diabetes and obesity, chronic kidney disease (CKD) is increasing across the globe. Although some data support an effect of maternal obesity on offspring kidney, the impact of paternal obesity is unknown; thus, we have studied the effect of paternal obesity prior to conception. Male Sprague Dawley rats were fed chow diet or high fat diet (HFD) for 13-14 weeks before mating with chow-fed females. Male offspring were weaned onto chow and killed at 27 weeks for renal gene expression and histology. Fathers on HFD were 30% heavier than Controls at mating. At 27 weeks of age offspring of obese fathers weighed 10% less; kidney triglyceride content was significantly increased (5.35 ± 0.84 vs. 2.99 ± 0.47 μg/mg, p < 0.05, n = 8 litters per group. Histological analysis of the kidney demonstrated signs of tubule damage, with significantly greater loss of brush border, and increased cell sloughing in offspring of obese compared to Control fathers. Acat1, involved in entry of fatty acid for beta-oxidation, was significantly upregulated, possibly to counteract increased triglyceride storage. However other genes involved in lipid metabolism, inflammation and kidney injury showed no changes. Paternal obesity was associated with renal triglyceride accumulation and histological changes in tubules, suggesting a mild renal insult in offspring, who may be at risk of developing CKD.

Parental determinants of metabolic syndrome among adolescent Asian Indians: A cross-sectional analysis of parent-offspring trios

BACKGROUND

The aim of the present study was to investigate the relationship between parental metabolic syndrome (MS) and the risk of MS and associated abnormalities in adolescent offspring.

METHODS

This cross-sectional study was performed on 304 adolescents (12-16 years; 236 children with at least one parent and 124 father-mother-child trios) recruited from four schools representing different socioeconomic strata from Vellore, India. Anthropometric data was collected and blood pressure, blood glucose, and lipids were measured.

RESULTS

The prevalence of MS in adolescent offspring, fathers, and mothers was 3.3%, 52.5%, and 48.7% respectively. The most commonly observed metabolic abnormality among adolescents was lower high-density lipoprotein. Maternal waist circumference (WC) was strongly correlated with adolescent body mass index (P = 0.007), WC (P < 0.001), serum triglycerides (P = 0.02), and systolic (P = 0.005) and diastolic (P = 0.01) blood pressure. Maternal MS status was significantly associated with a greater risk of central obesity (WC odds ratio [OR] 2.02; 95% confidence interval [CI] 1.21-3.17) in offspring. Both parents having MS conferred a significant effect on the child's WC (OR 1.21; 95% CI 1.72-2.07) and increased risk of MS (OR 6.19; 95% CI 1.64-23.26).

CONCLUSIONS

This study highlights the possible heritable parental components that may contribute to the MS phenotype in offspring: MS in adolescent offspring is related to parental MS status, and maternal traits reflect offspring adiposity and metabolic traits more strongly than paternal factors. Therefore, adolescent children of parents with MS should be targets for primordial prevention of cardiometabolic disease.

Familial Risk of Chronic Musculoskeletal Pain and the Importance of Physical Activity and Body Mass Index: Prospective Data from the HUNT Study, Norway

The main objectives of the current study was i) to prospectively examine if chronic musculoskeletal pain in parents is associated with risk of chronic musculoskeletal pain in their adult offspring, and ii) to assess if these parent-offspring associations are modified by offspring body mass index and leisure time physical activity. We used data on 4,742 adult offspring linked with their parents who participated in the population-based HUNT Study in Norway in 1995–97 and in 2006–08. Family relations were established through the national Family Registry. A Poisson regression model was used to estimate relative risk (RR) with 95% confidence interval (CI). In total, 1,674 offspring (35.3%) developed chronic musculoskeletal pain during the follow-up period of approximately 11 years. Both maternal (RR: 1.26, 95% CI: 1.03, 1.55) and paternal chronic musculoskeletal pain (RR: 1.29, 95% CI: 1.06, 1.57) was associated with increased risk of offspring chronic musculoskeletal pain. Compared to offspring of parents without chronic musculoskeletal pain, the adverse effect of parental pain was somewhat stronger among offspring who reported a low (RR: 1.82, 95% CI: 1.32, 2.52) versus high (RR: 1.32, 95% CI: 0.95, 1.84) level of leisure time physical activity. Offspring of parents with chronic musculoskeletal pain and who were classified as obese had more than twofold increased risk (RR: 2.33, 95% CI: 1.68, 3.24) of chronic musculoskeletal pain compared to normal weight offspring of parents without pain. In conclusion, parental chronic musculoskeletal pain is positively associated with risk of chronic musculoskeletal pain in their adult offspring. Maintenance of normal body weight may reduce the risk of chronic musculoskeletal pain in offspring of pain-afflicted parents.

Maternal Blood Pressure During Pregnancy and Early Childhood Blood Pressures in the Offspring: The GUSTO Birth Cohort Study

Although epidemiological studies suggest that offspring of women with preeclampsia are at increased risk to higher blood pressures and cardiovascular disease, little is known about the nature of blood pressures between the mother and her offspring. As blood pressures comprise of both pulsatile (systolic blood pressure [SBP] and pulse pressure [PP]) and stable (diastolic blood pressure [DBP]) components, and they differ between central and peripheral sites, we sought to examine maternal peripheral and central blood pressure components in relation to offspring early childhood blood pressures. A prospective birth cohort of 567 Chinese, Malay, and Indian mother-offspring with complete blood pressure information were studied. Maternal brachial artery SBP, DBP, and PP were measured at 26 to 28 weeks gestation; and central SBP and PP were estimated from radial artery waveforms. Offspring brachial artery SBP, DBP, and PP were measured at 3 years of age. Associations between continuous variables of maternal blood pressures (peripheral SBP, DBP, PP, central SBP, and PP) and offspring blood pressures (peripheral SBP, DBP, and PP) were examined using multiple linear regression with adjustment for maternal characteristics (age, education level, parity, smoking status, alcohol consumption and physical activity during pregnancy, and pre-pregnancy BMI) and offspring characteristics (sex, ethnicity, BMI, and height at 3 years of age). In the multivariate models, offspring peripheral SBP increased by 0.08 (95% confidence interval 0.00-0.17, P = 0.06) mmHg with every 1-mmHg increase in maternal central SBP, and offspring peripheral PP increased by 0.10 (0.01-0.18, P = 0.03) mmHg for every 1-mmHg increase in maternal central PP. The relations of maternal-offspring peripheral blood pressures (SBP, DBP, and PP) were positive but not statistically significant, and the corresponding values were 0.05 (-0.03 to 0.13; P = 0.21), 0.03 (-0.04 to 0.10; P = 0.35), and 0.05 (-0.02 to 0.13; P = 0.14), respectively. Maternal central pulsatile blood pressure components (SBP and PP) during pregnancy are associated with higher blood pressures in the offspring. This positive correlation is already evident at 3-years old. Studies are needed to further evaluate the effects of maternal central pulsatile blood pressure components during pregnancy and long-term cardiovascular health in the offspring.

Is there a greater maternal than paternal influence on offspring adiposity in India?

Previous research has provided conflicting evidence regarding fetal roots of adiposity in India. To compare the strength of association between maternal and paternal body mass indexes (BMIs) corrected for height with offspring BMI in India to examine the potential for intrauterine mechanisms to influence offspring adiposity in India, we analysed a sample of 16,528 mother-father-offspring trios from the 2005 to 2006 Indian National Family Health Survey. Children were aged 0-59 months with parents aged 15-49 years (mothers) and 15-54 years (fathers). Linear and logistic regression models, specified in multiple ways, were used to estimate associations between parental BMI* (BMI redefined by power term x (kg/m(x)) to be independent from height), and child BMI/top decile of child BMI. Higher values of maternal BMI and paternal BMI were associated with higher values of offspring BMI. In comparing the effects of maternal BMI and paternal BMI, however, no consistent differences were found in the strength of these parental influences on offspring BMI. In the fully adjusted linear model, the standardised coefficient was 0.131 (95% CI 0.110 to 0.154) for maternal BMI* and 0.079 (95% CI 0.056 to 0.103) for paternal BMI*; with evidence of heterogeneity between maternal-offspring and paternal-offspring associations (p=0.005). This was not robust in the unstandardised regression (β=0.056, 95% CI 0.044 to 0.067 for maternal BMI and β=0.039, 95% CI 0.025 to 0.053 for paternal BMI, p=0.093). Mixed results indicate that compared with paternal BMI, maternal BMI did not have a consistently stronger influence on offspring BMI in India.

Body mass index is associated with the maternal lines but height is heritable across family lines in the Lifeways Cross-Generation Cohort Study

OBJECTIVES

Overweight and obesity is a problem in children in particular and determining pathways of transmission is important in prevention. We aimed to examine associations for body mass index (BMI) across three generations of the same families.

PARTICIPANTS

Members of 556 families in the Lifeways Cross-Generation Cohort Study 2001-2014.

SETTING

Community-based study with linkage to health records in the Republic of Ireland.

METHODS

Employing a novel mixed-method approach which adjusts for age and familial group, BMI correlations were estimated at three ages of the index child, that is, at birth and at ages 5 and 9. Height was also examined for comparative purposes.

RESULTS

Correlation of offspring's BMI with that of the mother increased with age (correlation coefficient 0.15 increasing to 0.28, p value <0.001 in all cases) while no consistent pattern was seen with offspring and fathers. There was an association also with each parent and their own mother. Offspring's BMI was correlated to a lesser extent with that of the maternal grandmother while for girls only there was an association with that of the paternal grandmother at ages 0 and 5 (correlation coefficients 0.25, 0.28, p values 0.02, 0.01, respectively). In contrast, height of the child was strongly associated with those of all family members at age 5, but at birth and at age 9 only there was an association with those of the parents and the paternal grandfather. Correlation of offspring's height with those of the mother and father increased with age.

CONCLUSIONS

The results suggest that BMI is predominantly associated with the maternal line, possibly either with intrauterine development, or inherited through the X chromosome, or both, while height is a more complex trait with genetic influences of the parents and that of the paternal grandfather predominating.

Parent-offspring association of metabolic syndrome in the Framingham Heart Study

BACKGROUND

Metabolic syndrome (MetS) is a clustering of five metabolic risk factors including abdominal obesity, elevated blood pressure, hypertriglyceridemia, low high-density lipoprotein cholesterol (HDL-C), and impaired fasting glucose. Few studies have fully reported the strength of clustering of these risk factors in a parent-offspring relationship. This analysis describes the associations between parents and their adult offspring in regard to MetS. It also estimates the association between each risk factor in parents and the presence of MetS in their offspring.

METHODS

We analyzed data for 1193 offspring (565 sons, and 628 daughters) from the Framingham Offspring Study who attended examinations 5, 6, and 7. Information about their parents was collected from examinations 13, 14 and 15 of the Framingham Original Cohort study. We used pedigree file to combine parental and offspring's data. Participants were classified as having the MetS according to the Adult Treatment Panel III criteria. Analyses were conducted separately for mothers and fathers. Logistic regression was used to estimate the associations.

RESULTS

After adjusting for age, education, smoking, alcohol consumption and physical activity level of offspring, no significant association was found between father's and their offspring's MetS. Mother's MetS was significantly and positively associated with their daughter's MetS (adjusted odds ratio or adj OR: 1.63; 95% confidence Interval, CI:1.02-2.61), but not with their sons' MetS. When analyzed by individual components, maternal impaired glucose (adj OR: 2.03; 95% CI: 1.02- 9.31), abdominal obesity (adj OR: 1.56; 95% CI: 0.98- 2.55) and low HDL-C (adj OR: 2.12; 95% CI: 1.36-3.32) were associated daughter's MetS. Maternal low HDL-C and raised total cholesterol showed marginal association with son's MetS. For fathers, only impaired glucose (adj OR: 4.91; 95% CI: 2.07- 11.68) was associated with their daughter's MetS.

CONCLUSIONS

Using the data from Framingham Heart Study, we demonstrate differential association of MetS and its components between parents and offspring. Mother's MetS was strongly related with daughter's MetS, but the association was inconsistent with son's MetS. No association was found between father's MetS and offspring's Mets. These results provide evidence that daughters with mother's MetS are in higher risk than daughters or sons with father's MetS.

Transgenerational effects of parental cardiovascular disease and risk factors on offspring mortality: family-linkage data from the HUNT Study, Norway

BACKGROUND

Cardiovascular risk factors are known to be associated between parents and offspring. However, whether these associations are reflected in increased offspring mortality has not been extensively studied.

DESIGN

This was a family study of 32,536 father-offspring and 39,614 mother-offspring pairs who participated in the HUNT Study, Norway.

METHODS

Adjusted hazard ratios (HRs) for offspring total and cardiovascular mortality associated with parental levels of cardiovascular disease risk factors were estimated using Cox regression.

RESULTS AND CONCLUSIONS

Fathers' and mothers' reporting of cardiovascular disease (HRs: 1.18; 95% CI 1.04-1.32 and 1.20; 1.07-1.35, respectively), diabetes (HRs: 1.22; 95% CI 1.00-1.49 and 1.21; 1.05-1.40, respectively), and current smoking (HRs: 1.21; 95% CI 1.08-1.36 and 1.30; 1.15-1.47, respectively) was associated with total mortality in offspring. An inverse association was found with maternal height (HR: 0.95; 95% CI 0.91-0.99), and a suggestive inverse association with paternal height (HR: 0.98; 95% CI 0.93-1.03). Relations with offspring cardiovascular mortality were less clear and consistent. Offspring whose parents both had a risk factor did not seem to have higher mortality than would be expected from the independent effects of each parent.

Approaches for drawing causal inferences from epidemiological birth cohorts: a review

Large-scale population-based birth cohorts, which recruit women during pregnancy or at birth and follow up their offspring through infancy and into childhood and adolescence, provide the opportunity to monitor and model early life exposures in relation to developmental characteristics and later life outcomes. However, due to confounding and other limitations, identification of causal risk factors has proved challenging and published findings are often not reproducible. A suite of methods has been developed in recent years to minimise problems afflicting observational epidemiology, to strengthen causal inference and to provide greater insights into modifiable intra-uterine and early life risk factors. The aim of this review is to describe these causal inference methods and to suggest how they may be applied in the context of birth cohorts and extended along with the development of birth cohort consortia and expansion of "omic" technologies.