Birth weight is inversely associated with coronary heart disease in post-menopausal women: findings from the British women's heart and health study

Birth weight, ideal cardiovascular health metrics in adulthood, and incident cardiovascular disease

BACKGROUND

Prenatal and postnatal factors may have joint effects on cardiovascular health, and we aimed to assess the joint association of birth weight and ideal cardiovascular health metrics (ICVHMs) prospectively in adulthood with incident cardiovascular disease (CVD).

METHODS

In the UK Biobank, 227,833 participants with data on ICVHM components and birth weight and without CVD at baseline were included. The ICVHMs included smoking, body mass index, physical activity, diet information, total cholesterol, blood pressure, and hemoglobin A1c. The Cox proportional hazards model was used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) in men and women.

RESULTS

Over a median follow-up period of 13.0 years (2,831,236 person-years), we documented 17,477 patients with incident CVD. Compared with participants with birth weights of 2.5-4.0 kg, the HRs (95% CIs) of CVD among those with low birth weights was 1.08 (1.00-1.16) in men and 1.23 (1.16-1.31) in women. The association between having a birth weight <2.5 kg and CVD risk in men was more prominent for those aged <50 years than for those of older age ( P for interaction = 0.026). Lower birth weight and non-ideal cardiovascular health metrics were jointly related to an increased risk of CVD. Participants with birth weights <2.5 kg and ICVHMs score 0-1 had the highest risk of incident CVD (HR [95% CI]: 3.93 [3.01-5.13] in men; 4.24 [3.33-5.40] in women). The joint effect (HR [95% CI]: 1.36 [1.17-1.58]) could be decomposed into 24.7% (95% CI: 15.0%-34.4%) for a lower birth weight, 64.7% (95% CI: 56.7%-72.6%) for a lower ICVHM score, and 10.6% (95% CI: 2.7%-18.6%) for their additive interaction in women.

CONCLUSIONS

Birth weight and ICVHMs were jointly related to CVD risk. Attaining a normal birth weight and ideal ICVHMs may reduce the risk of CVD, and a simultaneous improvement of both prenatal and postnatal factors could further prevent additional cases in women.

Lower birth weight is linked to poorer cardiovascular health in middle-aged population-based adults

OBJECTIVE

To examine associations of birth weight with clinical and imaging indicators of cardiovascular health and evaluate mechanistic pathways in the UK Biobank.

METHODS

Competing risk regression was used to estimate associations of birth weight with incident myocardial infarction (MI) and mortality (all-cause, cardiovascular disease, ischaemic heart disease, MI), over 7-12 years of longitudinal follow-up, adjusting for age, sex, deprivation, maternal smoking/hypertension and maternal/paternal diabetes. Mediation analysis was used to evaluate the role of childhood growth, adulthood obesity, cardiometabolic diseases and blood biomarkers in mediating the birth weight-MI relationship. Linear regression was used to estimate associations of birth weight with left ventricular (LV) mass-to-volume ratio, LV stroke volume, global longitudinal strain, LV global function index and left atrial ejection fraction.

RESULTS

258 787 participants from white ethnicities (61% women, median age 56 (49, 62) years) were studied. Birth weight had a non-linear relationship with incident MI, with a significant inverse association below an optimal threshold of 3.2 kg (subdistribution HR: 1.15 (1.08 to 1.22), p=6.0×10-5) and attenuation to the null above this threshold. The birth weight-MI effect was mediated through hypertension (8.4%), glycated haemoglobin (7.0%), C reactive protein (6.4%), high-density lipoprotein (5.2%) and high cholesterol (4.1%). Birth weight-mortality associations were statistically non-significant after Bonferroni correction. In participants with cardiovascular magnetic resonance (n=19 314), lower birth weight was associated with adverse LV remodelling (greater concentricity, poorer function).

CONCLUSIONS

Lower birth weight was associated with greater risk of incident MI and unhealthy LV phenotypes; effects were partially mediated through cardiometabolic disease and systemic inflammation. These findings support consideration of birth weight in risk prediction and highlight actionable areas for disease prevention.

Birthweight of children with isolated congenital heart disease-A sibling analysis study

OBJECTIVE

Congenital heart disease (CHD) is associated with decreased birthweight (BW) compared to population-based references. The aim of this study was to compare the BW of isolated CHD cases to their siblings, thus controlling for unknown and unmeasured confounders within the family.

METHODS

All isolated CHD cases in the Leiden University Medical Center were included (2002-2019). Generalized estimated equation models were constructed to compare BW z scores of CHD neonates with their siblings. Cases were clustered to minor or severe CHD and stratified according to the aortic flow and oxygenation to the brain.

RESULTS

The overall BW z score of siblings was 0.032 (n = 471). The BW z score was significantly lower in CHD cases (n = 291) compared to their siblings (-0.20, p = 0.005). The results were consistent in the subgroup analysis of severe and minor CHD (BW z score difference -0.20 and -0.10), but did not differ significantly (p = 0.63). Stratified analysis regarding flow and oxygenation showed no BW difference between the groups (p = 0.1).

CONCLUSION

Isolated CHD cases display a significantly lower BW z score compared to their siblings. As the siblings of these CHD cases show a BW distribution similar to the general population, this suggests that shared environmental and maternal influences between siblings do not explain the difference in BW.

Associations of birth weight and later life lifestyle factors with risk of cardiovascular disease in the USA: A prospective cohort study

BACKGROUND

Low birth weight has been associated with a greater risk of cardiovascular disease (CVD). However, the interaction between low birth weight and adult lifestyle factors on the risk of CVD remains unclear.

METHODS

We included 20,169 men from the Health Professionals Follow-up Study (HPFS, 1986-2016), 52,380 women from the Nurses' Health Study (NHS, 1980-2018), and 85,350 women from the Nurses' Health Study II (NHS II, 1991-2017) in the USA who reported birth weight and updated data on adult body weight, smoking status, physical activity, and diet every 2-4 years. Incident cases of CVD, defined as a combined endpoint of fatal and nonfatal coronary heart disease (CHD) and stroke, were self-reported and confirmed by physicians through reviewing medical records.

FINDINGS

During 4,370,051 person-years of follow-up, 16,244 incident CVD cases were documented, including 12,126 CHD and 4118 stroke cases. Cox proportional hazards regression models revealed an increased risk of CHD during adulthood across categories of decreasing birth weight in all cohorts (all P for linear trend <0.001). Additionally, we found an additive interaction between decreasing birth weight and unhealthy lifestyles on the risk of CHD among women, with a pooled relative excess risk due to interaction of 0.06 (95% CI: 0.04-0.08). The attributable proportions of the joint effect were 23.0% (95% CI: 11.0-36.0%) for decreasing birth weight alone, 67.0% (95% CI: 58.0-75.0%) for unhealthy lifestyle alone, and 11.0% (95% CI: 5.0-17.0%) for their additive interaction. Lower birth weight was associated with a greater stroke risk only among women, which was independent of later-life lifestyle factors.

INTERPRETATION

Lower birth weight may interact synergistically with unhealthy lifestyle factors in adulthood to further increase the risk of CHD among women.

FUNDING

The National Institutes of Health grants.

The Cardiovascular Disease (CVD) Risk Continuum from Prenatal Life to Adulthood: A Literature Review

The risk of developing cardiovascular diseases (CVDs) arises from the interaction of prenatal factors; epigenetic regulation; neonatal factors; and factors that affect childhood and adolescence, such as early adiposity rebound (AR) and social and environmental influences. Thus, CVD risk varies between the group of low-risk metabolically healthy normal-weight subjects (MHNW); the intermediate-risk group, which includes metabolically healthy obese (MHO) and metabolically unhealthy normal-weight subjects (MUHNW); and the high-risk group of metabolically unhealthy obese (MUHO) subjects. In this continuum, several risk factors come into play and contribute to endothelial damage, vascular and myocardial remodeling, and atherosclerotic processes. These pathologies can occur both in prenatal life and in early childhood and contribute to significantly increasing CVD risk in young adults over time. Early intervention in the pediatric MUHO population to reduce the CVD risk during adulthood remains a challenge. In this review, we focus on CVD risk factors arising at different stages of life by performing a search of the recent literature. It is urgent to focus on preventive or early therapeutic strategies to stop this disturbing negative metabolic trend, which manifests as a continuum from prenatal life to adulthood.

DNA methylation signatures in cord blood associated with birthweight are enriched for dmCpGs previously associated with maternal hypertension or pre-eclampsia, smoking and folic acid intake

Many epidemiological studies have linked low birthweight to an increased risk of non-communicable diseases (NCDs) in later life, with epigenetic proceseses suggested as an underlying mechanism. Here, we sought to identify neonatal methylation changes associated with birthweight, at the individual CpG and genomic regional level, and whether the birthweight-associated methylation signatures were associated with specific maternal factors. Using the Illumina Human Methylation EPIC array, we assessed DNA methylation in the cord blood of 557 and 483 infants from the UK Pregnancies Better Eating and Activity Trial and Southampton Women's Survey, respectively. Adjusting for gestational age and other covariates, an epigenome-wide association study identified 2911 (FDR≤0.05) and 236 (Bonferroni corrected p ≤ 6.45×10-8) differentially methylated CpGs (dmCpGs), and 1230 differentially methylated regions (DMRs) (Stouffer ≤0.05) associated with birthweight. The top birthweight-associated dmCpG was located within the Homeobox Telomere-Binding Protein 1 (HMBOX1) gene with a 195 g (95%CI: -241, -149 g) decrease in birthweight per 10% increase in methylation, while the top DMR was located within the promoter of corticotropin-releasing hormone-binding protein (CRHBP). Furthermore, the birthweight-related dmCpGs were enriched for dmCpGs previously associated with gestational hypertension/pre-eclampsia (14.51%, p = 1.37×10-255), maternal smoking (7.71%, p = 1.50 x 10-57) and maternal plasma folate levels during pregnancy (0.33%, p = 0.029). The identification of birthweight-associated methylation markers, particularly those connected to specific pregnancy complications and exposures, may provide insights into the developmental pathways that affect birthweight and suggest surrogate markers to identify adverse prenatal exposures for stratifying for individuals at risk of later NCDs.

Low Birth Weight and Prematurity Are Associated with Hypertensive Disorder of Pregnancy in Later Life: A Cross-Sectional Study in Japan

OBJECTIVE

We previously reported that hypertensive disorder of pregnancy (HDP) was a risk factor for hypertension and hypercholesterolemia in later life. Additionally, the age-adjusted odds ratio (OR) of HDP was 2.72 for Japanese women whose mothers had a history of HDP versus those whose mothers did not. This study aimed to clarify the association of HDP with birth weight and gestational age.

STUDY DESIGN

A self-administered baseline survey of the Japanese Nurses' Health Study (JNHS) cohort was conducted from 2001 to 2007. Data on 17,278 parous female nurses who knew their own birth weights were extracted from the JNHS baseline survey (n = 49,927) and subjected to cross-sectional, retrospective analysis. Data on weeks of gestation, birth weight, and history of HDP were collected.

RESULTS

The age-adjusted ORs for HDP were 1.62 (95% confidence interval [CI]: 1.20-2.19) for birth weight <2,000 g, 1.24 (CI: 1.04-1.48) for 2,000 to 2,499 g, 1.11 (CI: 1.00-1.23) for 2,500 to 2,999 g, and 1.08 (CI: 0.94-1.24) for ≥3,500 g compared with 3,000 to 3,499 g. The age-adjusted ORs for HDP were 1.27 (95% CI: 1.04-1.54) for a gestational age < 37 weeks and 0.93 (0.70-1.23) for ≥42 weeks compared with 37-41 weeks. The age-adjusted OR of the birth weight score for HDP in later life was 0.98 (CI: 0.94-1.03; Cochran-Armitage trend test: z = 0.401, p = 0.688).

CONCLUSION

Among women in Japan, a history of low birth weight and prematurity are risk factors for HDP in later life. The risk of HDP among women born with low birth weight and/or premature deserves attention.

Childhood Risk Factors and Adulthood Cardiovascular Disease: A Systematic Review

OBJECTIVE

To conduct a comprehensive review of the literature on childhood risk factors and their associations with adulthood subclinical and clinical cardiovascular disease (CVD).

STUDY DESIGN

A systematic search was performed using the MEDLINE, EMBASE, PsycINFO, CINAHL, and Web of Science databases to identify English-language articles published through June 2018. Articles were included if they were longitudinal studies in community-based populations, the primary exposure occurred during childhood, and the primary outcome was either a measure of subclinical CVD or a clinical CVD event occurring in adulthood. Two independent reviewers screened determined whether eligibility criteria were met.

RESULTS

There were 210 articles that met the predefined criteria. The greatest number of publications examined associations of clinical risk factors, including childhood adiposity, blood pressure, and cholesterol, with the development of adult CVD. Few studies examined childhood lifestyle factors including diet quality, physical activity, and tobacco exposure. Domains of risk beyond "traditional" cardiovascular risk factors, such as childhood psychosocial adversity, seemed to have strong published associations with the development of CVD.

CONCLUSIONS

Although the evidence was fairly consistent in direction and magnitude for exposures such as childhood adiposity, hypertension, and hyperlipidemia, significant gaps remain in the understanding of how childhood health and behaviors translate to the risk of adulthood CVD, particularly in lesser studied exposures like glycemic indicators, physical activity, diet quality, very early life course exposure, and population subgroups.

Developmental and Early Life Origins of Cardiometabolic Risk Factors: Novel Findings and Implications

The intent of this review is to critically consider the data that support the concept of programming and its implications. Birth weight and growth trajectories during childhood are associated with cardiometabolic disease in adult life. Both extremes, low and high birth weight coupled with postnatal growth increase the early presence of cardiometabolic risk factors and vascular imprinting, crucial elements of this framework. Data coming from epigenetics, proteomics, metabolomics, and microbiota added relevant information and contribute to better understanding of mechanisms as well as development of biomarkers helping to move forward to take actions. Research has reached a stage in which sufficiently robust data calls for new initiatives focused on early life. Prevention starting early in life is likely to have a very large impact on reducing disease incidence and its associated effects at the personal, economic, and social levels.

Birth weight is inversely correlated with blood pressure: population-based study

BACKGROUND AND METHOD

The current representative national cross-sectional study examines the association of birth weight and blood pressure (BP) among the adult Australian population.Questions about birth weight were added to the second round of AusDiab study. Hypertension was defined based on WHO (≥140/90), and NCEP-ATPIII (≥130/85). Both definitions were examined against the continuous birth weight and dichotomous variable of low birth weight (LBW); less than 2.5 kg, adjusting for age, BMI, physical activity, smoking, alcohol intake and socioeconomic factors.

RESULTS

A total of 4502 respondents reported their birth weights with a mean (SD) of 3.37 (0.7) kg. Females with LBW had significantly higher mean SBP and DBP than those with normal birth weight. This relationship persisted with adjustments for various confounding factors. Males with LBW showed a trend towards a higher SBP and DBP, though NS, than normal birth weight more than 2.5 kg. LBW individuals, less than 2.5 kg were at higher risk for having high SBP hypertension at least 140/90 mmHg and at least 130/85 mmHg compared with those with normal birth weight. Among females, for each kilogramme of birth weight, there was a predicted decrease of 1.59 (0.7, 2.5) mmHg in SBP, P = 0.001 and 0.85 (0.2, 1.5) mmHg in DBP, P = 0.001; after adjustments for age, body size, physical activity, smoking status, alcohol intake and socioeconomic factors. Among males, for each kilogramme of birth weight, there was a decrease of 1.74 (0.7, 2.8) mmHg in SBP, P = 0.002 and 1.06 (0.3, 1.9) mmHg in DBP, P = 0.008 after adjustments for all confounding factor.

CONCLUSION

This study has examined the association of birth weight and BP in a representative adult population. LBW was significantly associated with the risk of developing high BP.

Birthweight predicts adult cardiovascular disorders: Population based cross sectional survey

BACKGROUND

Cardiovascular disease (CVD) is the primary cause of death in the developed-countries and mostly in the poorer areas of the country, and in lower income-groups.

HYPOTHESIS

Birthweight predicts adult development of angina, coronary heart disease, stroke, and combination of all CVD.

METHODS

The AusDiab is a cross-sectional study of Australians aged 25 years or over. Data on age, sex, previous-CVD, smoking-status, alcohol-intake, time-spent on watching television and physical-activity, total house-income, dwelling-type and education-level were collected by interviewer- administered-questionnaires.

RESULTS

Four thousand five hundred and two had birthweights (mean (SD) of 3.4(0.7) kg). Females in the lowest birthweight-quintile were at least 1.23, 1.48, 1.65, and 1.23 times more likely to have angina, CAD, stroke, and CVS compared to the referent group ≥3.72 kg with P = .123, .09, .099, and 0.176, respectively. Similarly, males in the lowest-birthweight-quintile were 1.23, 1.30, 1.39, and 1.26 times more likely to have angina, CAD, stroke, and CVS compared to the referent-group ≥4.05 kg with P = .231, .087, .102, and .123, respectively. Females with low birth weight (LBW) were at least 1.39, 1.40, 2.30, and 1.47 times more likely to have angina, CAD, stroke and CVS compared to those ≥2.5 kg with P = .06, .19, .03, and .13, respectively. Similarly, males with LBW were 1.76, 1.48, 3.34, and 1.70 times more likely to have angina, CAD, stroke, and CVS compared to those ≥2.5 kg with P = .14, .13, .03, and .08, respectively.

CONCLUSION

there was a negative relationship between birth weight and angina, CAD, stroke, and the overall CVS. It would be prudent, to adopt policies of intensified whole of life surveillance of lower-birthweight people, anticipating this risk.

Elevated blood pressure in high-fat diet-exposed low birthweight rat offspring is most likely caused by elevated glucocorticoid levels due to abnormal pituitary negative feedback

Being delivered as a low birthweight (LBW) infant is a risk factor for elevated blood pressure and future problems with cardiovascular and cerebellar diseases. Although premature babies are reported to have low numbers of nephrons, some unclear questions remain about the mechanisms underlying elevated blood pressure in full-term LBW infants. We previously reported that glucocorticoids increased miR-449a expression, and increased miR-449a expression suppressed Crhr1 expression and caused negative glucocorticoid feedback. Therefore, we conducted this study to clarify the involvement of pituitary miR-449a in the increase in blood pressure caused by higher glucocorticoids in LBW rats. We generated a fetal low-carbohydrate and calorie-restricted model rat (60% of standard chow), and some individuals showed postnatal growth failure caused by growth hormone receptor expression. Using this model, we examined how a high-fat diet (lard-based 45kcal% fat)-induced mismatch between prenatal and postnatal environments could elevate blood pressure after growth. Although LBW rats fed standard chow had slightly higher blood pressure than control rats, their blood pressure was significantly higher than controls when exposed to a high-fat diet. Observation of glomeruli subjected to periodic acid methenamine silver (PAM) staining showed no difference in number or size. Aortic and cardiac angiotensin II receptor expression was altered with compensatory responses. Blood aldosterone levels were not different between control and LBW rats, but blood corticosterone levels were significantly higher in the latter with high-fat diet exposure. Administration of metyrapone, a steroid synthesis inhibitor, reduced blood pressure to levels comparable to controls. We showed that high-fat diet exposure causes impairment of the pituitary glucocorticoid negative feedback via miR-449a. These results clarify that LBW rats have increased blood pressure due to high glucocorticoid levels when they are exposed to a high-fat diet. These findings suggest a new therapeutic target for hypertension of LBW individuals.

Birthweight and Lipids in Adult Life: Population-Based Cross Sectional Study

The purpose of this study was to examine the association of birthweight with lipid profile in the general adult population. Participants in the second-wave of a nationally representative cross sectional AusDiab-study were asked to complete a birthweight questionnaire. Fasting total cholesterol (TC), LDL-C, HDL-C, and triacylglycerol levels were modeled against birthweight. Four thousand five hundred and two people reported their birthweights, mean (SD) of 3.4(0.7) kg. Females with low birthweight-LBW had higher levels of TC, LDL-C, and triacylglycerols, but no difference in HDL-C, than those with normal-birthweight-NBW;≥2.5 kg. People with LBW showed a trend toward increased risk for high TC (≥5.5 mmol/L) compared to NBW. Among females with LBW, the risk for high LDL-C (≥3.5 mmol/L) was increased compared to those of NBW. The risk for low HDL-C (<0.9 mmol/L) was increased among males with LBW compared to those with NBW. Examination of the relationship on the continuum showed no differences except for high triacylglycerol levels among females with the lowest birthweight quintile compared to the higher birthweight quintile. However, the risk for various abnormalities by birthweight quintiles was similar to that when we used the traditional definition of LBW vs. NBW. Females and males with low birthweight differ in their risk for lipids abnormalities. Females had higher risk for high LDL-C, whereas males had high risk for low HDL-C (<0.9 mmol/L). In addition, females with low birthweight had the highest triacylglycerol levels. High LDL-C, low HDL-C, and high triacylglycerols are well-recognized risk factors for cardiovascular disease.

Birth Weight and Risk of Type 2 Diabetes Mellitus, Cardiovascular Disease, and Hypertension in Adults: A Meta-Analysis of 7 646 267 Participants From 135 Studies

Background Low birth weight has been associated with increased risk of type 2 diabetes mellitus, cardiovascular disease, and hypertension, but the risk at high birth weight levels remains uncertain. This systematic review and meta-analysis aimed to clarify the shape of associations between birth weight and aforementioned diseases in adults and assessed sex-specific risks. Methods and Results We systematically searched PubMed, EMBASE , and Web of Science for studies published between 1980 and October 2016. Studies of birth weight and type 2 diabetes mellitus (T2 DM ), cardiovascular disease ( CVD ), and hypertension were included. Random-effects models were used to derive the summary relative risks and corresponding 95% confidence intervals.We identified 49 studies with 4 053 367 participants assessing the association between birth weight and T2 DM , 33 studies with 5 949 477 participants for CVD , and 53 studies with 4 335 149 participants for hypertension and high blood pressure. Sex-specific binary analyses showed that only females had an increased risk of T2 DM and CVD at the upper tail of the birth weight distribution. While categorical analyses of 6 birth weight groups and dose-response analyses showed J-shaped associations of birth weight with T2 DM and CVD , the association was inverse with hypertension. The lowest risks for T2 DM , CVD , and hypertension were observed at 3.5 to 4.0, 4.0 to 4.5, and 4.0 to 4.5 kg, respectively. Conclusions These findings indicate that birth weight is associated with risk of T2 DM and CVD in a J-shaped manner and that this is more pronounced among females.

Long-term cardiovascular consequences of fetal growth restriction: biology, clinical implications, and opportunities for prevention of adult disease

In the modern world, cardiovascular disease is a leading cause of death for both men and women. Epidemiologic studies consistently have suggested an association between low birthweight and/or fetal growth restriction and increased rate of cardiovascular mortality in adulthood. Furthermore, experimental and clinical studies have demonstrated that sustained nutrient and oxygen restriction that are associated with fetal growth restriction activate adaptive cardiovascular changes that might explain this association. Fetal growth restriction results in metabolic programming that may increase the risk of metabolic syndrome and, consequently, of cardiovascular morbidity in the adult. In addition, fetal growth restriction is strongly associated with fetal cardiac and arterial remodeling and a subclinical state of cardiovascular dysfunction. The cardiovascular effects ocurring in fetal life, includes cardiac morphology changes, subclinical myocardial dysfunction, arterial remodeling, and impaired endothelial function, persist into childhood and adolescence. Importantly, these changes have been described in all clinical presentations of fetal growth restriction, from severe early- to milder late-onset forms. In this review we summarize the current evidence on the cardiovascular effects of fetal growth restriction, from subcellular to organ structure and function as well as from fetal to early postnatal life. Future research needs to elucidate whether and how early life cardiovascular remodeling persists into adulthood and determines the increased cardiovascular mortality rate described in epidemiologic studies.

Better Diet Quality during Pregnancy Is Associated with a Reduced Likelihood of an Infant Born Small for Gestational Age: An Analysis of the Prospective New Hampshire Birth Cohort Study

Background

Birth weight has a U-shaped relation with chronic disease. Diet quality during pregnancy may impact fetal growth and infant birth weight, yet findings are inconclusive.

Objective

We examined the relation between maternal diet quality during pregnancy and infant birth size among women enrolled in a prospective birth cohort.

Methods

Women 18-45 y old with a singleton pregnancy were recruited at 24-28 wk of gestation from prenatal clinics in New Hampshire. Women completed a validated food frequency questionnaire at enrollment. Diet quality was computed as adherence to the Alternative Healthy Eating Index. Infant birth outcomes (sex, head circumference, weight, and length) were extracted from medical records. Weight-for-length z scores, low birth weight, macrosomia, and size for gestational age [small for gestational age (SGA) or large for gestational age (LGA)] were computed. Multivariable regression models fit each outcome on quartiles of diet quality, adjusted for covariates. Models were computed overall and stratified by smoking status.

Results

Analyses included 862 women and infants with complete data. Lower diet quality was associated with lower maternal education, being a smoker, prepregnancy obesity status, and lack of exercise during pregnancy. Overall, 3.4% of infants were born with a low birth weight, 12.1% with macrosomia, 4.6% were SGA, and 8.7% were LGA. In an adjusted model, increased diet quality appeared linearly associated with a reduced likelihood of SGA (P-trend = 0.03), although each quartile comparison did not reach statistical significance. Specifically, ORs for SGA were 0.89 (95% CI: 0.37, 2.15), 0.73 (95% CI: 0.28, 1.89), and 0.35 (95% CI: 0.11, 1.08) for each increasing quartile of diet quality compared to the lowest quartile. Similar trends for SGA were observed among non-smokers (n = 756; P-trend = 0.07). Also among non-smokers, increased diet quality was associated with lower infant birth weight (P-trend = 0.03) and a suggested reduction in macrosomia (P-trend = 0.07).

Conclusions

Increased diet quality during pregnancy was related to a reduced risk of SGA in this cohort of pregnant women from New Hampshire. Additional studies are needed to elucidate the relation between maternal diet quality and macrosomia.

Long term effects of fetal undernutrition on rat heart. Role of hypertension and oxidative stress

Background and aims

Fetal undernutrition is a risk factor for heart disease in both genders, despite the protection of women against hypertension development. Using a rat model of maternal undernutrition (MUN) we aimed to assess possible sex differences in the development of cardiac alterations and the implication of hypertension and cardiac oxidative stress.

Methods

Male and female offspring from rats fed ad libitum (control) or with 50% of the normal daily intake during the second half of gestation (MUN) were used. Heart weight/body weight ratio (HW/BW), hemodynamic parameters (anaesthetized rats) and plasma brain natriuretic peptide (BNP, ELISA) were assessed in 21-day, 6-month and 22-month old rats. Plasma testosterone (ELISA) and cardiac protein expression of enzymes related to reactive oxygen species synthesis (p22^phox, xanthine-oxidase) and degradation (catalase, Cu/Zn-SOD, Mn-SOD, Ec-SOD) were evaluated in 21-day and 6-month old rats (Western Blot). Heart structure and function was studied at the age of 22 months (echocardiography).

Results

At the age of 21 days MUN males exhibited significantly larger HW/BW and cardiac p22^phox expression while females had reduced p22^phox expression, compared to their respective sex-matched controls. At the age of 6-months, MUN males showed significantly larger blood pressure and cardiac xanthine-oxidase expression; MUN females were normotensive and had a lower cardiac expression of antioxidant enzymes, compared to their respective sex-matched controls. At the age of 22 months, both MUN males and females showed larger HW/BW and left ventricular mass and lower ejection fraction compared to sex-matched controls; only MUN males exhibited hypertension and a larger plasma BNP compared to aged male controls.

Conclusions

1) During perinatal life females exposed to fetal undernutrition are protected from cardiac alterations, but in ageing they exhibit ventricular hypertrophy and functional loss, like MUN males; 2) cardiac oxidative stress might be implicated in the observed heart alterations in both sexes and 3) the severity of cardiac damage might be greater in males due to hypertension.

Birth weight was longitudinally associated with cardiometabolic risk markers in mid-adulthood

PURPOSE

Birth weight (BW) is associated with risk of cardiovascular (CV) disease. The findings from studies examined the association of BW with metabolic markers of CV risk were inconsistent and controversial. We examined the association of BW with insulin resistance and blood lipids using repeated measures up to mid-adulthood.

METHODS

Data from seven screenings of the Bogalusa Heart Study-a longitudinal study of cardiovascular risk factors in Bogalusa, LA-are analyzed using generalized estimation equations method. Participants with birth data and at least one measurement of study outcomes between 18 and 44 years (n = 2,034) were included.

RESULTS

BW is inversely associated with insulin resistance, triglycerides, and total cholesterol (P < .01 for all). For 1-kg decrease in BW, insulin resistance increased by 2.3 units, 95% confidence interval (CI) = 0.7-3.9; triglycerides by 8.7 mg per dL, 95% CI = 4.9-12.4, and total cholesterol by 5.4 mg per dL, 95% CI = 1.8-9.1. The association of body mass with adult blood lipids levels is weaker in persons with low versus normal BW.

CONCLUSIONS

The study provides strong evidence of an inverse relationship of BW with adulthood cardiometabolic risk profile. Persons born with low BW are maybe less responsive to preventive interventions aiming at weight reduction.

Perinatal risk factors for premature ischaemic heart disease in a Swedish national cohort

OBJECTIVE

Several studies have reported associations between restricted fetal development, as shown by birth weight or birth length, and later ischaemic heart disease (IHD). However, few studies have examined the importance of these perinatal factors when taking into account gestational age at birth, hereditary factors, sociodemographic factors and comorbidities. This study investigated the importance of perinatal risk factors for premature IHD and myocardial infarction (MI) in a large Swedish cohort.

SETTING AND PARTICIPANTS

National cohort study of 1,970,869 individuals who were live-born in Sweden in 1973 through 1992, and followed up to 2010 (ages 18-38 years).

PRIMARY AND SECONDARY OUTCOME MEASURES

The main outcome was IHD, and the secondary outcome was MI.

RESULTS

A total of 668 individuals were diagnosed with IHD in 18.8 million person-years of follow-up. After adjusting for gestational age at birth, sociodemographic factors, comorbidities and family history of IHD, low fetal growth was associated with increased risk of IHD (HR for <-2 vs -1 to <1 SD, 1.54; 95% CI 1.15 to 2.07; p=0.004) and increased risk of MI (HR for <-2 vs -1 to <1 SD, 2.48; 95% CI 1.66 to 3.71; p<0.001) in young adulthood. In contrast, gestational age at birth was not associated with the risk of IHD or MI.

CONCLUSIONS

In this large national cohort, low fetal growth was strongly associated with IHD and MI in young adulthood, independently of gestational age at birth, sociodemographic factors, comorbidities and family history of IHD.

Fetal programming and cardiovascular pathology

Low birth weight serves as a crude proxy for impaired growth during fetal life and indicates a failure for the fetus to achieve its full growth potential. Low birth weight can occur in response to numerous etiologies that include complications during pregnancy, poor prenatal care, parental smoking, maternal alcohol consumption, or stress. Numerous epidemiological and experimental studies demonstrate that birth weight is inversely associated with blood pressure and coronary heart disease. Sex and age impact the developmental programming of hypertension. In addition, impaired growth during fetal life also programs enhanced vulnerability to a secondary insult. Macrosomia, which occurs in response to maternal obesity, diabetes, and excessive weight gain during gestation, is also associated with increased cardiovascular risk. Yet, the exact mechanisms that permanently change the structure, physiology, and endocrine health of an individual across their lifespan following altered growth during fetal life are not entirely clear. Transmission of increased risk from one generation to the next in the absence of an additional prenatal insult indicates an important role for epigenetic processes. Experimental studies also indicate that the sympathetic nervous system, the renin angiotensin system, increased production of oxidative stress, and increased endothelin play an important role in the developmental programming of blood pressure in later life. Thus, this review will highlight how adverse influences during fetal life and early development program an increased risk for cardiovascular disease including high blood pressure and provide an overview of the underlying mechanisms that contribute to the fetal origins of cardiovascular pathology.

Can 'early programming' be partly explained by smoking? Results from a prospective, population-based cohort study

BACKGROUND

Numerous studies have focused the association between low birthweight and later disease. Our objective was to study the association between birthweight and later adult smoking and thereby explore a possible mechanism for the association between low birthweight and later adult disease.

METHODS

We studied associations between birthweight of women (n=247704) born in 1967-1995 and smoking habits at the end of their pregnancy 13-42 years later in a prospective, population-based cohort study from The Medical Birth Registry of Norway. Similarly, the association between birthweight of men (n=194393) and smoking habits of their partners were assessed. Finally, we studied the relation between smoking habits of the participating women and the cause specific death of their mothers (n=222808).

RESULTS

Twenty per cent of women with birthweight less than 2000 g were adult daily smokers compared with 11% with birthweight 4000-4499 g [relative risk=1.8, 95% confidence interval 1.4, 2.2]. Similarly, we found an association between men's birthweight and their partners smoking habits. Mothers of smoking women had doubled risk of dying from lung cancer and from cardiovascular disease compared with mothers of non-smoking women.

CONCLUSIONS

Being born with low birthweight is associated with smoking in adulthood. Associations of adult smoking with partners' birthweight and mothers' smoking-related causes of death suggest a shared smoking environment, and may account for some of the established association between birthweight and later cardiovascular disease.

Sex differences in the developmental origins of cardiovascular disease

The Developmental Origins of Health and Disease (DOHaD) proposes that adverse events during early life program an increased risk for cardiovascular disease. Experimental models provide proof of concept but also indicate that insults during early life program sex differences in adult blood pressure and cardiovascular risk. This review will highlight the potential mechanisms that contribute to the etiology of sex differences in the developmental programming of cardiovascular disease.

Contemporary and historical evidence to suggest that women's preference for age at birth of first child remains consistent across time

Women's ability to reproduce is restricted by menarche and menopause. First children are, however, not typically born until some years after the onset of puberty. Other factors therefore contribute towards this delay. In this context, women's hips do not reach full adult form until they are in their mid-20s. Therefore, physiological and morphological factors appear to determine an optimum age-range for reproduction. The following studies were conducted in order to investigate this hypothesis. Study 1 asked nulliparous women questions about ages at which particular life events related to reproduction should ideally occur. This revealed their preferred age at birth of first child to be approximately 27 years old. Study 2 replicated these findings and further showed that women with children actually had their first child at a very similar age (27.93 [±0.79]). Findings from Study 3 were also remarkably consistent (28.15 [±0.39]). Study 4 examined the 1901 U.K. Census record and incorporated an analysis of the influence of wealth. Middle class women were on average 24.88 (±0.22) years old at the birth of their first child. Poor women were on average 23.50 (±0.20) years old. These figures at least approximate to findings from Studies 1-3, which is noteworthy given that modern contraceptive methods were not widely available at the time. It is concluded that female strategies to delay giving birth to their first child until they are of an age that approaches or coincides with their full hip maturation are enduring across time.

Birth weight and risk of coronary heart disease in adults: a meta-analysis of prospective cohort studies

Some studies have found a significant relationship between birth weight (BW) and the risk of coronary heart disease (CHD) in adulthood, but results were inconsistent. The purpose of this study was to characterize the association between BW and the risk of CHD in adults. Among 144 papers detected by our search, 27 papers provided data on the relationship between BW and CHD, of which 23 papers considered BW as a continuous variable, and 14 articles considered BW as a categorical variable for this meta-analysis. Based on 23 papers, the mean weighted estimate for the association between BW and the combined outcome of non-fatal and fatal CHD was 0.83 [95% confidence interval (CI), 0.80-0.86] per kilogram of BW (P<0.0001). Low birth weight (LBW<2500 g) was associated with increased risk of CHD [odds ratio (OR), 1.19; 95% confidence interval (CI), 1.11-1.27] compared with subjects with BW⩾2500 g. LBW, as compared with normal BW (2500-4000 g), was associated with increased risk of CHD (OR, 1.16; 95% CI, 1.08-1.25). High birth weight (HBW⩾4000 g) was associated with decreased risk of CHD (OR, 0.89; 95% CI, 0.81-0.98) compared with subjects with BW<4000 g. In addition, there was an indication (not quite significant) that HBW was associated with a lower risk of CHD (OR, 0.89; 95% CI, 0.79-1.01), as compared with normal BW. No significant evidence of publication bias was present. These results suggest that LBW is significantly associated with increased risk of CHD and a 1 kg higher BW is associated with a 10-20% lower risk of CHD.

Effect of low birth weight on women's health

PURPOSE

The theory of the developmental origins of health and disease hypothesizes that low birth weight (≤5.5 lb) indicative of poor fetal growth is associated with an increased risk of chronic, noncommunicable disease in later life, including hypertension, type 2 diabetes mellitus, and osteoporosis. Whether women are at greater risk than men is not clear. Experimental studies that mimic the cause of slow fetal growth are being used to examine the underlying mechanisms that link a poor fetal environment with later chronic disease and investigate how sex and age affect programmed risk. Thus, the aims of this review are to summarize the current literature related to the effect of low birth weight on women's health and provide insight into potential mechanisms that program increased risk of chronic disease across the lifespan.

METHODS

A search of PubMed was performed with the keywords low birth weight, women's health, female, and sex differences; additional terms included blood pressure, hypertension, renal, cardiovascular, obesity, glucose intolerance, type 2 diabetes, osteoporosis, bone health, reproductive senescence, menopause, and aging.

FINDINGS

The major chronic diseases associated with low birth weight include high blood pressure and cardiovascular disease, impaired glucose homeostasis and type 2 diabetes, impaired bone mass and osteoporosis, and early reproductive aging.

IMPLICATIONS

Low birth weight increases the risk of chronic disease in men and women. Low birth weight is also associated with increased risk of early menopause. Further studies are needed to fully address the effect of sex and age on the developmental programming of adult health and disease in women across their lifespan.

Early life factors in relation to cardiovascular risk and cardiovascular disease in old age in Bergen: a Norwegian retrospective cohort study based on the Hordaland Health Study (HUSK)

Objectives

The fetal origins of adult disease hypothesis describes associations found for fetal or early-life exposures with cardiovascular risk and disease in adulthood. The extension or not of these associations into old age has received less attention. We investigated if maternal health and family circumstances were associated with cardiovascular risk factors and cardiovascular disease (CVD) in late life and discuss results in light of possible selection effects and measurement error.

Design

A retrospective cohort study based on community survey. We examined 224 possible associations between anthropometric measures, maternal health information and family socioeconomic status at birth versus CVD and CVD-related risk factors 72–74 years later.

Participants

Of 3341 participants in a community survey of people aged 72–74 years, we were able to trace birth records from a historical archive in a broadly representative subsample of 480.

Setting

Bergen, Norway

Main outcome measures

Established cardiovascular risk factors and indicators of CVD.

Results

Only 11 (4.9%) of these associations were found to be statistically significant, and no strong or consistent patterns in the associations between exposures and outcomes were found.

Conclusions

There was little evidence in this relatively elderly sample for an association between early life factors and CVD outcomes of clinical or public health relevance. Further research is required to confirm the extent to which a diminution of early life influences into old age, if genuine, can be accounted for by selective mortality, systematic bias or by dilution of effects due to competing risk factors.

Small birth size, adult overweight, and risk of acute myocardial infraction

BACKGROUND

The association between small size at birth and increased risk of cardiovascular disease in adulthood is well established. This relationship is commonly interpreted according to the "thrifty phenotype hypothesis," which states that the association is generated by a mismatch between fetal and postnatal nutrition. Empirical support for an interaction between impaired fetal growth and later overnutrition is, however, sparse and partly conflicting.

METHODS

The Stockholm Heart Epidemiology Program is a population-based case-control study of risk factors for acute myocardial infarction (MI); data were available for 1058 cases and 1478 controls. Using logistic regression, we studied the effect of size at birth, and its interactive effect with body mass index (BMI), at 3 occasions in adulthood, on the risk of MI. Biologic interaction was estimated with the synergy index.

RESULTS

Very low birth weight for gestational age was associated with increased risk of MI (odds ratio [OR] = 2.0; 95% confidence interval [CI] = 1.4-2.9; attributable fraction = 5%). In nonfatal cases, adjustment for waist-hip ratio, insulin resistance, blood pressure, and lipids reduced the point estimate somewhat. Low birth weight for gestational age in combination with high BMI at the time of the MI produced an OR of 10.8 (3.6-31.8) for MI compared with normal birth weight and normal BMI; the synergy index was 6.5 (95% CI = 1.8-24.0).

CONCLUSIONS

The synergism between small size at birth and high adult BMI supports the thrifty phenotype hypothesis. However, this mechanism seems to pertain to only a small fraction of the acute MI cases, implying minor public health importance.

Socioeconomic disparities in adverse birth outcomes: a systematic review

CONTEXT

Adverse birth outcomes, such as preterm birth and low birth weight, have serious health consequences across the life course. Socioeconomic disparities in birth outcomes have not been the subject of a recent systematic review. The aim of this study was to systematically review the literature on the association of socioeconomic disadvantage with adverse birth outcomes, with specific attention to the strength and consistency of effects across socioeconomic measures, birth outcomes, and populations.

EVIDENCE ACQUISITION

Relevant articles published from 1999 to 2007 were obtained through electronic database searches and manual searches of reference lists. English-language studies from industrialized countries were included if (1) study objectives included examination of a socioeconomic disparity in a birth outcome and (2) results were presented on the association between a socioeconomic predictor and a birth outcome related to birth weight, gestational age, or intrauterine growth. Two reviewers extracted data and independently rated study quality; data were analyzed in 2008-2009.

EVIDENCE SYNTHESIS

Ninety-three of 106 studies reported a significant association, overall or within a population subgroup, between a socioeconomic measure and a birth outcome. Socioeconomic disadvantage was consistently associated with increased risk across socioeconomic measures, birth outcomes, and countries; many studies observed racial/ethnic differences in the effect of socioeconomic measures.

CONCLUSIONS

Socioeconomic differences in birth outcomes remain pervasive, with substantial variation by racial or ethnic subgroup, and are associated with disadvantage measured at multiple levels (individual/family, neighborhood) and time points (childhood, adulthood), and with adverse health behaviors that are themselves socially patterned. Future reviews should focus on identifying interventions to successfully reduce socioeconomic disparities in birth outcomes.

Health disparities beginning in childhood: a life-course perspective

In this article we argue for the utility of the life-course perspective as a tool for understanding and addressing health disparities across socioeconomic and racial or ethnic groups, particularly disparities that originate in childhood. Key concepts and terms used in life-course research are briefly defined; as resources, examples of existing literature and the outcomes covered are provided along with examples of longitudinal databases that have often been used for life-course research. The life-course perspective focuses on understanding how early-life experiences can shape health across an entire lifetime and potentially across generations; it systematically directs attention to the role of context, including social and physical context along with biological factors, over time. This approach is particularly relevant to understanding and addressing health disparities, because social and physical contextual factors underlie socioeconomic and racial/ethnic disparities in health. A major focus of life-course epidemiology has been to understand how early-life experiences (particularly experiences related to economic adversity and the social disadvantages that often accompany it) shape adult health, particularly adult chronic disease and its risk factors and consequences. The strong life-course influences on adult health could provide a powerful rationale for policies at all levels--federal, state, and local--to give more priority to investment in improving the living conditions of children as a strategy for improving health and reducing health disparities across the entire life course.

Birth weight and lung function in a cohort of Chinese school children

OBJECTIVE

Evidence on the association between birth weight and lung function is conflicting. We evaluated the children's lung function in relation to their birth weight in China.

METHODS

A prospective cohort study was conducted in 1,599 school children. Baseline data on birth weight and other potential confounding variables were obtained from self-administered questionnaires. Pulmonary function tests were performed with a standard procedure and repeated 6 months later.

RESULTS

There were no significant differences in the standard deviation score (SDS) of forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) between children with low birth weight (LBW) and those with normal birth weight (NBW). The growth rates in lung function between children with LBW and NBW were also insignificant.

CONCLUSIONS

No association between birth weight and lung function was found among Chinese school children.

Head size at birth and long-term mortality from coronary heart disease

BACKGROUND

Many studies have shown that low birthweight is associated with increased risk of heart disease in adulthood. It is controversial whether this association is caused by genetic or non-genetic factors, and whether life course exposures, such as adult overweight, could modify the association. We have studied the association of head circumference at birth with later deaths from coronary heart disease (CHD), and assessed whether maternal height and adult body mass could modify the association.

METHODS

Population-based cohort study of 35,846 men and women born between 1920 and 1959 with mortality follow-up from 1961 to 2005.

RESULTS

During follow-up, 630 people died from CHD and there was an inverse association of head circumference with deaths from CHD (Ptrend = 0.010). The association was modified by maternal height (Pinteraction = 0.01) and by adult body mass (Pinteraction = 0.05). People in the lowest third of head circumference, who had a tall mother or a high body mass index in adulthood, were at the highest risk of death from CHD.

CONCLUSIONS

Head circumference at birth was inversely associated with deaths from CHD, and the combination of small head and tall mother, or small head and high adult body mass, was associated with the highest risk. These findings suggest that combined effects of genetic factors (growth potential and intrauterine growth) and non-genetic factors acting throughout the life course (intrauterine growth restriction and later weight gain) could mediate the effects of birth size on adult heart disease.

Birth weight and stages of CKD: a case-control study in an Australian population

BACKGROUND

In view of recent reports of the relationship of kidney disease to birth weight, we evaluate the relationship between birth weight and chronic kidney disease (CKD), including end-stage kidney disease, in Australian adults.

STUDY DESIGN

A case-control study.

SETTING & PARTICIPANTS

Patients attending the nephrology department at a major metropolitan hospital in Australia were asked to recall their birth weight, excluding those with structural kidney abnormalities. Two controls for each patient, matched for sex and within 5 years of age, were selected from participants from the Australian Diabetes, Obesity and Lifestyle (AusDiab) Study, who had also been asked to report their birth weight.

PREDICTOR

Birth weight in kilograms.

OUTCOMES & MEASUREMENTS

CKD and stages were defined using the National Kidney Foundation-Kidney Disease Outcomes Quality Initiative classification, proteinuria as a marker of kidney damage, and glomerular filtration rate estimates, by using the Modification of Diet in Renal Disease Study equation.

RESULTS

Of 189 patients with CKD who reported their birth weights for whom controls were identified, 106 were men. Mean age was 60.3 +/- 15 (SD) years. Mean birth weight overall was 3.27 +/- 0.6 versus 3.46 +/- 0.6 kg for their controls (P < 0.001), and proportions with birth weights less than 2.5 kg were 12.2% and 4.4% (P < 0.001). In patients with CKD, 22.8%, 21.7%, 18%, and 37.6% were in CKD stages 2 (n = 43), 3 (n = 41), 4 (n = 34), and 5 (n = 71), respectively. Birth weights by CKD stage and their AusDiab controls were as follows: stage 2, 3.38 +/- 0.52 versus 3.49 +/- 0.52 kg; P = 0.2; stage 3, 3.28 +/- 0.54 versus 3.44 +/- 0.54 kg; P = 0.1; stage 4, 3.19 +/- 0.72 versus 3.43 +/- 0.56 kg; P = 0.1; and stage 5, 3.09 +/- 0.65 versus 3.47 +/- 0.67 kg; P < 0.001. Differences in birth weights applied to women and men and people younger than 60 and 60 years and older and were present in the major "causal" categories of renal disease.

LIMITATIONS

Birth weight is by self-recall with a significant nonresponse rate to the questionnaire in both cases and controls.

CONCLUSIONS

Urban Australian patients with CKD had lower birth weights than their matched Australian controls. In addition, the more advanced the CKD stage, the lower the birth weight. Thus, lower birth weights appear to predispose to CKD and to its progression. Among possible explanations is the documented association between birth weight and nephron number.

The influence of birth weight and body mass in early adulthood on early coronary heart disease risk among Danish men born in 1953

This study examines the joint and separate influence of birth weight and body mass in young adulthood on subsequent coronary heart disease (CHD) risk. A cohort of 9,143 men born in Copenhagen, Denmark, in 1953, for whom information on birth weight and body weight and height around age 19 years were retrieved from birth certificates and conscript records, respectively, were followed from 1978 until 2005 (between age 25 and 52 years) for incident fatal and non-fatal CHD. Data on CHD were obtained through record linkage to the Cause of Death Registry and the National Patient Registry. During follow-up, a total of 475 men had a CHD diagnosis. Men with low birth weight, high body mass index (BMI) at age 19, a father from the working class, and low educational level at age 19 had an increased risk for CHD. Birth weight was inversely associated with CHD only in men with BMI of 25 kg/m(2) or above. Adjustment for childhood social circumstances and educational status at age 19 had minor influence on the estimates. In conclusion, BMI in young adulthood seems to be strongly associated with the risk of CHD before age 52, and birth weight seem to modify the association. The risk estimates is highest for individuals with a combination of low birth weight and overweight in young adulthood.

Cardiovascular disease in a cohort exposed to the 1940-45 Channel Islands occupation

Background

To clarify the nature of the relationship between food deprivation/undernutrition during pre- and postnatal development and cardiovascular disease (CVD) in later life, this study examined the relationship between birth weight (as a marker of prenatal nutrition) and the incidence of hospital admissions for CVD from 1997–2005 amongst 873 Guernsey islanders (born in 1923–1937), 225 of whom had been exposed to food deprivation as children, adolescents or young adults (i.e. postnatal undernutrition) during the 1940–45 German occupation of the Channel Islands, and 648 of whom had left or been evacuated from the islands before the occupation began.

Methods

Three sets of Cox regression models were used to investigate (A) the relationship between birth weight and CVD, (B) the relationship between postnatal exposure to the occupation and CVD and (C) any interaction between birth weight, postnatal exposure to the occupation and CVD. These models also tested for any interactions between birth weight and sex, and postnatal exposure to the occupation and parish of residence at birth (as a marker of parish residence during the occupation and related variation in the severity of food deprivation).

Results

The first set of models (A) found no relationship between birth weight and CVD even after adjustment for potential confounders (hazard ratio (HR) per kg increase in birth weight: 1.12; 95% confidence intervals (CI): 0.70 – 1.78), and there was no significant interaction between birth weight and sex (p = 0.60). The second set of models (B) found a significant relationship between postnatal exposure to the occupation and CVD after adjustment for potential confounders (HR for exposed vs. unexposed group: 2.52; 95% CI: 1.54 – 4.13), as well as a significant interaction between postnatal exposure to the occupation and parish of residence at birth (p = 0.01), such that those born in urban parishes (where food deprivation was worst) had a greater HR for CVD than those born in rural parishes. The third model (C) found no interaction between birth weight and exposure to the occupation (p = 0.43).

Conclusion

These findings suggest that the levels of postnatal undernutrition experienced by children, adolescents and young adults exposed to food deprivation during the 1940–45 occupation of the Channel Islands were a more important determinant of CVD in later life than the levels of prenatal undernutrition experienced in utero prior to the occupation.

Familial (shared environmental and genetic) factors and the foetal origins of cardiovascular diseases and type 2 diabetes: a review of the literature

Several researchers have argued that observed associations between birth weight and cardiovascular diseases, and type 2 diabetes, may be confounded by familial (shared environmental and genetic) factors. However, most studies have found that shared environmental factors, including socio-economic factors, do not influence the foetal origins of adult diseases. Results from two twin studies suggest that genetic factors may be of importance for the association between birth weight and risks of coronary heart disease, but findings from intergenerational studies are not consistent with genetic confounding. More studies have assessed the importance of genetic factors with respect to risk factors of coronary heart, including raised blood pressure and lipid levels. Recent findings suggest that the association between birth weight and hypertension is independent of genetic factors. In contrast, recent twin and intergenerational studies favour the hypothesis that the association between birth weight and risk of type 2 diabetes is confounded by genetic factors.

Perinatal Risk Factors for Ischemic Heart Disease

Background— Several studies have reported an association between low birth weight and ischemic heart disease, but it remains unclear whether the association is mediated through poor fetal growth or short gestational duration.

Methods and Results— In a cohort study, we have identified all subjects born preterm or with a low birth weight at 4 major delivery units in Sweden from 1925 through 1949. For comparison, an equal number of subjects with none of these criteria were identified within the same source population. The study population consists of 6425 subjects, of whom 2931 were born before 37 weeks of gestation and 2176 had a birth weight <2500 g. Fetal growth was estimated through birth weight for gestational age. The cohort was followed up for occurrence of ischemic heart disease through the nationwide Hospital Discharge and Cause of Death Registries during the period of 1987 through 2002. In the cohort, 617 cases of ischemic heart disease occurred. Compared with subjects with a normal fetal growth, those born small for gestational age (birth weight ≤−2 SD below the mean) were at increased risk of ischemic heart disease (adjusted hazard ratio, 1.64; 95% confidence interval, 1.23 to 2.18). The negative association between fetal growth and risk of ischemic heart disease was independent of gestational duration.

Conclusions— The association between low birth weight and adult risk of ischemic heart disease appears to be mediated entirely by poor fetal growth.

The associations between birthweight and adult markers of liver damage and function

Evidence suggesting an effect of fetal growth on liver development and function stems from both animal and human studies. The association of birthweight with adult markers of liver damage and function was examined in a random sample of 2101 British women aged 60-79 years. Age-adjusted natural logged levels of alanine aminotransferase (ALT) and gamma glutamyltransferase (GGT) decreased linearly across increasing thirds of birthweight. Alkaline phosphatase (ALP) levels were higher in women of the lowest third of the birthweight distribution compared with other women. No evidence was found for associations of birthweight with aspartate aminotransferase (AST), total bilirubin and albumin. After full adjustment for social class, physical activity, smoking and alcohol consumption, an increase in one standard deviation of birthweight (691 g) was associated with a 2% ([95% CI 0%, 4%], P = 0.021) decrease in the geometric mean of ALT, a 4% decrease in GGT ([95% CI 1%, 6%], P = 0.008) and a 2% decrease in ALP ([95% CI 0%, 3%], P = 0.001). Associations of birthweight with ALT and GGT, but not with ALP, were attenuated when adjusting for components of the metabolic syndrome. These findings suggest that factors affecting intrauterine growth may increase the propensity for adult liver damage. The attenuation of associations with adjustment for components of the metabolic syndrome is in line with non-alcoholic fatty liver disease, indicated by elevated ALT and GGT, being the hepatic manifestation of the metabolic syndrome, and of the influence of perinatal factors on this syndrome.

Disorders of glucose regulation in adults and birth weight: results from the Australian Diabetes, Obesity and Lifestyle (AUSDIAB) Study

OBJECTIVE

The purpose of this study was to examine the association of birth weight with indexes of glycemia in a population-based survey.

RESEARCH DESIGN AND METHODS

A total of 10,788 participants in the Australian Diabetes, Obesity and Lifestyle (AusDiab) Study were asked to complete a birth weight questionnaire. Fasting plasma glucose (FPG), postload glucose (PLG), and A1C were modeled against birth weight. World Health Organization criteria were used to define impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and diabetes.

RESULTS

Among 7,157 participants who responded to the questionnaire, 4,502 reported their birth weights, with a mean +/- SD of 3.4 +/- 0.7 kg. FPG, PLG, and A1C were strongly and inversely correlated with birth weight. The odds ratios (95% CI) for high (>90th sex-specific percentile) FPG, PLG, and A1C were 0.83 (0.71-0.96), 0.74 (0.65-0.84), and 0.81 (0.70-0.94), respectively, for a 1-kg increase in birth weight after adjustment for age and sex. In those with low birth weight (LBW), the risks for having IFG, IGT, and diabetes and for all abnormalities combined were increased by 1.75, 2.22, 2.76, and 2.28, respectively, for women and by 1.40, 1.32, 1.98, and 1.49 for men compared with risks for those with normal birth weight. These trends applied across categories of age and BMI.

CONCLUSIONS

In an affluent Western country with a good adult health profile, birth weight has an inverse relationship with indexes of glycemia, and individuals with LBW were predisposed to higher rates of glycemic dysregulation in adult life. These associations were independent of BMI and of other factors significantly correlated with glycemic dysregulation.

Is birth weight a risk factor for ischemic heart disease in later life?

BACKGROUND

An inverse association between birth weight and ischemic heart disease (IHD) has been seen in observational studies.

OBJECTIVE

We wanted to determine the strength and consistency of the association between birth weight and subsequent IHD.

DESIGN

We conducted a systematic review of observational studies.

RESULTS

Seventeen published studies of birth weight and subsequent IHD were identified that included a total of 144,794 singletons. Relative risk estimates for the association between birth weight and IHD were available from 16 of these studies. Additional data from 2 unpublished studies of 3801 persons were also included. In total, the analyses included data from 18 studies on 4210 nonfatal and 3308 fatal IHD events in 147,009 persons. The mean weighted estimate for the association between birth weight and the combined outcome of nonfatal and fatal IHD was 0.84 (95% CI: 0.81, 0.88) per kilogram of birth weight (P<0.0001). No significant heterogeneity was observed between estimates in different studies (P=0.09), nor was there evidence of publication bias (P=0.3, Begg test). Neither restricting the analysis to fatal IHD events nor adjusting for socioeconomic status had any appreciable effect on the findings.

CONCLUSIONS

These findings are consistent with a 1 kg higher birth weight being associated with a 10-20% lower risk of subsequent IHD. However, even if causal, interventions to increase birth weight are unlikely to reduce the incidence of IHD materially. Further studies are needed to determine whether the observed association reflects a stronger underlying association with a related exposure or is due (at least in part) to residual confounding.

Birth weight, components of height and coronary heart disease: evidence from the Whitehall II study

BACKGROUND

Previous studies have suggested that shorter leg length, not trunk length, may explain the inverse association between height and coronary heart disease (CHD) risk. However, investigation of the importance of birth weight for these associations has been limited. This study examines associations of measures of stature and birth weight with CHD risk factors (measures of blood pressure and lipids, 2 h glucose, waist-hip ratio and fibrinogen) and incident non-fatal coronary events in middle age.

METHODS

Data were derived mostly from the Phase 5 (1997-99) clinical screening of the Whitehall II study of British civil servants. The main cross-sectional analyses included 1084 women and 2290 men with complete data.

RESULTS

In women total height and leg length were the measures that tended to be most strongly associated with CHD risk factors, while in men leg length demonstrated the closest associations. Although associations between trunk length and CHD risk factors were weaker, trunk length was the component of height that appeared to be most closely associated with coronary events. Associations between birth weight and CHD risk factors and coronary events were generally weaker than for any measure of stature. Adjustment for birth weight had little effect on associations between components of stature and CHD risk factors or events.

CONCLUSION

Findings from this relatively privileged cohort confirmed that shorter leg length underlies the inverse association between height and CHD risk factors in middle-aged women and men. Furthermore, in this study population shorter trunk length was more closely associated with incident, non-fatal coronary events.

Lifecourse weight patterns and adult-onset diabetes: the Glasgow Alumni and British Women's Heart and Health studies

OBJECTIVE

To examine the association between body weight measures across the lifecourse and the risk of adult-onset diabetes.

METHODS

We analysed data from the Glasgow Alumni Cohort and the British Women's Heart and Health Study (BWHHS). The former included 5,571 men and women who had height and weight measured at university, and reported birthweight, mid- and later-life weight in a postal questionnaire. The BWHHS analysis included 4,280 women who had height and weight measured in later adulthood and recalled their birthweight and early adult height and weight. Adult-onset diabetes was defined as doctor-diagnosed disease after age 30, either self-reported or abstracted from medical records.

RESULTS

Thirty nine women and 209 men (Glasgow Alumni study) and 314 women (BWHHS) had diabetes. Those with diabetes had lower mean birthweight than those without, although the differences were small. Individuals with diabetes were also shorter and heavier at all ages than those without diabetes. Being overweight during at least one time period in adult life was associated with an increased risk of diabetes, compared to those who were never overweight. While there was no age at which being overweight was particularly detrimental, the risk associated with being overweight was cumulative across the lifecourse.

CONCLUSIONS

Being overweight at any point during life is associated with an increased risk of adult-onset diabetes. The cumulative nature of this association reinforces the need to prevent the development of excess weight at an early age to reduce diabetes prevalence in coming decades.

Low birth weight is associated with reduced adiponectin concentration in adult

PURPOSE

Low birth weight has been associated with metabolic and vascular diseases, but the precise mechanism is debated. Adiponectin is one of the key molecules in metabolic disease, and a decrease in level precedes the onset of type 2 diabetes and development of atherosclerosis. Our aim is to examine whether low birth weight is associated with adiponectin concentration in adult.

METHODS

We conducted a population-based cross-sectional study of 2277 subjects (1661 men and 616 women) aged 35 to 66 years who had their self-reported birth weights and adiponectin concentrations measured as adults.

RESULTS

After adjusting for potential confounders, including age, sex, current body mass index (BMI), smoking status, alcohol consumption, and exercise, geometric mean adiponectin levels were 6.63, 6.45, 6.86, 7.05, 6.75, and 7.22 microg/mL for subjects with birth weights less than 2500, 2500 to less than 2800, 2800 to less than 3000, 3000 to less than 3200, 3200 to less than 3500, and greater than 3500 g, respectively. A positive association was found between birth weight and adiponectin concentration (trend p = 0.002). Stratified by current BMI of 25 kg/m2, a positive association was not observed for subjects with a BMI less than 25 kg/m2, but was pronounced in those with a BMI of 25 kg/m2 or greater.

CONCLUSION

This study indicates that low birth weight contributes to decreased adiponectin concentrations in adult life independently of current BMI, especially for obese subjects.

Birthweight and coronary heart disease in a cohort born 1857-1900 in Melbourne, Australia

BACKGROUND

The widely observed association between birth size and risk of later coronary heart disease (CHD) has not been examined in an impoverished pre-20th century birth cohort.

METHODS

Birth weights and maternal characteristics, for births between 1857 and 1900 in a charity hospital, were recorded from preserved ledgers. Names were linked to death certificates to determine age and cause of death. Death with CHD was coded using specific criteria, and survival analysis methods were used to relate risk of CHD to birth weight, allowing for competing causes of death and adjusting for potentially confounding maternal factors.

RESULTS

Death certificates were traced for 8,584 (53%) of 16,272 registered live-births. Survival analyses were confined to 2,938 subjects (1,572 male, 1,366 female) who survived beyond age 40, since none of the 486 CHD cases was recorded earlier. CHD risk increased with time, but there was no evidence that it was related to birth weight, in men or women.

CONCLUSIONS

We did not replicate findings in more recent cohorts. This may represent a true lack of association in a historical cohort who we believe remained impoverished through their early life. However, we acknowledge the strong possibility of misclassification of cause of death by the person filling in the death certificate and/or our coding criteria, and temporal change in diagnostic criteria for CHD. We cannot exclude the possibility that low birth weight babies 'programmed' in utero for later CHD were more likely to die in infancy, in this cohort with a high infant mortality rate.

Birth Weight and Adult Hypertension Cross-Sectional Study in a Japanese Workplace Population

BACKGROUND

Low birth weight has been associated with adult hypertension in several Western populations. This association needs to be evaluated in Japanese people.

METHODS AND RESULTS

A population-based cross-sectional study of 3,107 subjects (2,303 males and 804 females) aged 35-66 years was conducted. The participants responded to a questionnaire about their birth weights, blood pressure, medical history, parental history, and lifestyle factors. Hypertension was defined as systolic blood pressure > or =140 mmHg and/or diastolic blood pressure > or =90 mmHg and/or under treatment by anti-hypertensives. Multiple logistic regression analysis adjusted for age, sex, body mass index, parental history, and lifestyle revealed the adjusted odds ratios for hypertension were 1.26 (95% confidence interval: 0.88-1.80), 1.00 (reference), 0.89 (0.73-1.08) and 0.70 (0.49-1.00) in subjects in birth weight categories of <2,500 g, 2,500-<3,000 g, 3,000-<3,500 g, 3,500- g, respectively (p-value for trend =0.009). Furthermore, this inverse association was clearly pronounced in normal-weight subjects.

CONCLUSION

Low birth weight was independently associated with adult hypertension in the Japanese workplace population. Our results support the inverse association observed previously in Western populations and suggest that intrauterine environmental insults might lead to permanent changes in the metabolism and structure of the fetal organs influencing the regulation of blood pressure.

Birth weight is inversely associated with incident coronary heart disease and stroke among individuals born in the 1950s: findings from the Aberdeen Children of the 1950s prospective cohort study

BACKGROUND

Birth weight is inversely associated with cardiovascular disease risk factors, but few studies have examined the association with disease end points, in particular with stroke risk. Furthermore, previous studies demonstrating an inverse association between birth weight and coronary heart disease (CHD) risk have been conducted on populations born in the early part of the 20th century, when infant mortality rates were high. If the environmental factors associated with improvements in infant mortality rates over the last century explain the inverse association between birth weight and CHD risk, one would expect weaker associations in more contemporary birth cohorts.

METHODS AND RESULTS

We have examined the association in a large birth cohort of 10,803 (with an average of 239,000 person-years of follow-up) singleton births that occurred between 1950 and 1956. Our outcomes were hospital admissions for, and fatalities from, CHD (n=296) and stroke (n=107). Birth weight was inversely associated with CHD and stroke. The age-adjusted hazards ratio for a 1-kg increase in birth weight was 0.62 (95% CI 0.50 to 0.78) for CHD and 0.38 (95% CI 0.24 to 0.60) for stroke. Adjustment for gestational age, social class at birth, height and body mass index at school entry, gravidity, maternal age at birth, pregnancy-induced hypertension, antepartum hemorrhage, and maternal height did not alter the association with CHD but attenuated the association with stroke to 0.48 (95% CI 0.30 to 0.76). This attenuation resulted largely from adjustment for gestational age, which was linearly inversely related to stroke risk. Adjusted hazard ratios per sex and gestational age standardized z score of birth weight were 0.85 (95% CI 0.73 to 0.97) for CHD and 0.74 (95% CI 0.71 to 0.88) for stroke.

CONCLUSIONS

Birth weight is inversely associated with CHD and stroke in a population born at a time when environmental circumstances, as indexed by low infant mortality rates, were relatively advantageous for infants.

Association of birth weight with adult lung function: findings from the British Women's Heart and Health Study and a meta-analysis

BACKGROUND

The aim of this study was to examine the associations between birth weight and lung function in a cohort of women aged 60-79 years and to combine these results with those from other published studies in a systematic review and meta-analysis.

METHODS

The associations of self-reported birth weight with adult lung function (forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC) and forced expiratory flow rate during mid expiration (FEF(25-75)), all measured using standard procedures, were assessed in a cross sectional study of 2257 British women aged 60-79 years. A detailed literature search was used to identify all published studies of the association, and meta-analysis was used to pool the results from our study and all published studies.

RESULTS

There were positive linear associations between birth weight and all three measures of lung function in simple age and examining nurse adjusted regression models. However, with adjustment for height (squared), all three associations attenuated towards the null: adjusted (age, nurse, height2) change in FEV1 per 1 kg birth weight was 0.01 l (95% CI -0.02 to 0.04); in FVC was 0.02 l (95% CI -0.02 to 0.07), and in FEF(25-75) was 0.00 l (95% CI -0.04 to 0.04). Further adjustment for life course socioeconomic position, adult body mass index, and smoking did not alter these associations. The results were similar among life long non-smokers and those who had ever smoked. A meta-analysis of eight studies of adults suggested that there was a positive association between birth weight and FEV1: pooled increase in FEV1 per 1 kg in birth weight 0.048 l (95% CI 0.026 to 0.070) adjusted for age, smoking, and height (or height squared). There was no evidence of small study bias in this meta-analysis.

CONCLUSIONS

There is a modest positive association between birth weight and lung function which indicates that intrauterine factors might have a role in lung development.