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

Birth Weight, Cardiometabolic Factors, and Coronary Heart Disease: A Mendelian Randomization Study

CONTEXT

Observational studies have shown associations of birth weight (BW) with coronary heart disease (CHD), but results are inconsistent and do not distinguish the fetal or maternal effect of BW.

OBJECTIVE

This study aims to explore the causal association between BW and CHD, analyze the fetal and maternal contribution, and quantify mediating effects of cardiometabolic factors.

METHODS

Genetic variants from genome-wide association study summary-level data of own BW (N = 298 142), offspring BW (N = 210 267 mothers), and 16 cardiometabolic (anthropometric, glycemic, lipidemic, and blood pressure) factors were extracted as instrumental variables. We used two-sample Mendelian randomization study (MR) to estimate the causal effect of BW on CHD (60 801 cases and 123 504 controls from mixed ancestry) and explore the fetal and maternal contributions. Mediation analyses were conducted to analyze the potential mediating effects of 16 cardiometabolic factors using two-step MR.

RESULTS

Inverse variance weighted analysis showed that lower BW raised the CHD risk (β -.30; 95% CI: -0.40, -0.20) and consistent results were observed in fetal-specific/maternal-specific BW. We identified 5 mediators in the causal pathway from BW to CHD, including body mass index-adjusted hip circumference, triglycerides, fasting insulin, diastolic blood pressure, and systolic blood pressure (SBP), with mediated proportion ranging from 7.44% for triglycerides to 27.75% for SBP. Causality between fetal-specific and maternal-specific BW and CHD was mediated by glycemic factors and SBP, respectively.

CONCLUSION

Our findings supported that lower BW increased CHD risk and revealed that fetal-specific and maternal-specific BW may both contribute to this effect. The causality between BW and CHD was mediated by several cardiometabolic factors.

Association between birth weight and risk of cardiovascular disease: Evidence from UK Biobank

BACKGROUND AND AIMS

Birth weight has been linked to cardiovascular disease (CVD) risk in adulthood, but no consensus has emerged on the threshold of birth weight for the lowest CVD risk and few studies have examined potential interaction between birth weight and adult adiposity.

METHODS AND RESULTS

A total of 256,787 participants, who had birth weight data and were free of CVD at baseline, were included from UK Biobank. Multivariate restricted cubic splines and Cox regression models were used to assess the association between birth weight and CVD. We observed nonlinear inverse associations of birth weight with the risk of coronary heart disease (CHD), stroke, and heart failure. Participants with the first quintile of birth weight (≤2.85 kg) had higher risks for CHD (hazard ratio [HR] = 1.23, 95% confidence interval [CI]: 1.15-1.32), stroke (HR = 1.19, 95% CI: 1.03-1.37), and heart failure (HR = 1.28, 95% CI: 1.11-1.48), as compared to the fourth quintile (3.41-3.79 kg). There was a significant interaction between birth weight and adult body mass index (BMI) on CHD and heart failure (both P for interaction <0.001), showing the highest risk for those who had birth weight ≤2.85 kg and BMI ≥30 kg/m² (HR = 1.96, 95% CI: 1.70-2.25 and HR = 2.39, 95% CI: 1.77-3.22, respectively).

CONCLUSIONS

Our findings indicate nonlinear inverse associations between birth weight and CVD risk, with a threshold of 3.41-3.79 kg for the lowest risk. Moreover, low birth weight may interact with adult obesity to increase the risk of CHD and heart failure.

Birth weight modifies the association between a healthy Nordic diet and office blood pressure in old age

A healthy diet reduces risk for high blood pressure. A small body size at birth increases risk for high blood pressure. Our aim was to study whether birth weight modifies the association between a healthy Nordic diet, characterized by high intake of Nordic vegetables, fruits, and berries, whole-grain rye, oat, and barley, and rapeseed oil, and blood pressure. Finnish men and women (n = 960) born in 1934-1944 attended clinical visits including clinical measurements, and questionnaires in 2001-2004 and 2011-2013. Linear regression was applied to investigate the interactions between birth weight and Nordic diet (measured by the Baltic sea diet score (BSDS)) on blood pressure change during the 10-year follow-up. Baseline Nordic diet and birth weight showed a significant interaction on systolic blood pressure (SBP) (p = 0.02), and pulse pressure (PP) (p < 0.01) over a 10-year follow-up. In the lowest birth weight category (women < 2951 g, men < 3061 g), predicted SBP decreased across BSDS thirds (lowest (T1): 155 mmHg, highest (T3): 145 mmHg, p for linearity = 0.01) as did predicted PP (T1: 71 mmHg, T3: 63 mmHg, p < 0.01). In the middle birth weight category, predicted SBP increased across BSDS thirds (T1: 151 mmHg, T3: 155 mmHg, p = 0.02) as did predicted PP (T1: 67 mmHg, T3: 71 mmHg, p < 0.01). In the highest birth weight category, no associations were found. Higher adherence to a healthy Nordic diet was associated with lower SBP and PP in individuals with low birth weight but with higher SBP and PP in those with average birth weight.

The reasons why cardiologists should consider prematurity at birth and intrauterine growth retardation among risk factors

The survival percentage of infants born preterm has risen steadily worldwide thanks to the giant steps forward made in the field of perinatal (the period immediately after birth) and neonatal (the first 4 weeks of birth following delivery) medicine. However, prematurity at birth and consequent low birth weight still represent the major causes of neonatal morbidity and mortality. Infants born preterm are at high risk of developing neurological, ophthalmological, and gastrointestinal complications as well. Furthermore, extensive more recent epidemiological findings have demonstrated an increase in risk factors and a higher mortality rate due to cardiovascular causes in patients born preterm and/or with intrauterine growth restriction. The aim of this review is to provide scientific evidence about how the cardiovascular system may be negatively influenced by prematurity and by a low birth weight that should by rights be viewed as new cardiovascular risk factors. This condition is referred to as 'cardiovascular perinatal programming'. In the light of the above, an early, constant, and prolonged cardiovascular follow-up should be implemented in former preterm individuals.

Low birthweight is associated with an increased risk of LADA and type 2 diabetes: results from a Swedish case-control study

AIMS/HYPOTHESIS

Our aim was to investigate the association between birthweight and latent autoimmune diabetes in adults (LADA), a common diabetes form with features of both type 1 and type 2 diabetes.

METHODS

We used data from the Epidemiological Study of Risk Factors for LADA and Type 2 Diabetes (ESTRID), a Swedish population-based study. Eligible for the analysis were 134 incident LADA cases (glutamic acid decarboxylase antibody [GADA] positive), 350 incident type 2 diabetes cases (GADA negative) and 603 randomly selected controls. We present ORs and 95% CIs for LADA and type 2 diabetes in relation to birthweight, adjusted for sex, age, BMI and family history of diabetes.

RESULTS

Low birthweight increased the risk of LADA as well as the risk of type 2 diabetes; OR per kg reduction was estimated as 1.52 (95% CI 1.12, 2.08) and 1.58 (1.23, 2.04), respectively. The OR for participants weighing <3 kg compared with ≥4 kg at birth was estimated as 2.38 (1.23, 4.60) for LADA and 2.37 (1.37, 4.10) for type 2 diabetes. A combination of low birthweight (<3 kg) and current overweight (BMI ≥ 25) further augmented the risk: LADA, OR 3.26 (1.69, 6.29); and type 2 diabetes, OR 39.93 (19.27, 82.71). Family history of diabetes had little impact on these estimates.

CONCLUSIONS/INTERPRETATION

Our results suggest that low birthweight may be a risk factor for LADA of the same strength as for type 2 diabetes. These findings support LADA, despite its autoimmune component, having an aetiology that includes factors related to type 2 diabetes.

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.

Sex-specific impact of maternal-fetal risk factors on depression and cardiovascular risk 40 years later

Major depressive disorder (MDD) and cardiovascular disease (CVD) represent leading causes of morbidity and mortality worldwide. We tested the hypothesis that growth restriction and preeclampsia (referred to as fetal risk) are significant predictors of these conditions, with women at higher risk in adulthood. Adult offspring exposed to fetal risk factors and their discordant siblings were from two prenatal cohorts, whose mothers were followed through pregnancy and whom we recruited as adults 40 years later (n = 538; 250 males and 288 females). Subjects were psychiatrically diagnosed and underwent a stress challenge during which parasympathetic regulation was assessed by electrocardiogram, operationalized as high-frequency R-R interval variability (HF-RRV). Linear mixed models and generalized estimating equations were used to examine the relationship of fetal risk on HF-RRV, MDD and comorbidity of low HF-RRV (lowest 25th percentile) and MDD, including interactions with sex and socioeconomic status (SES). Fetal risk was significantly associated with low HF-RRV response (F = 3.64, P = 0.05), particularly among low SES (interaction: F = 4.31, P < 0.04). When stratified by MDD, the fetal risk impact was three times greater among MDD compared with non-MDD subjects (effect size: 0.21 v. 0.06). Females had a significantly higher risk for the comorbidity of MDD and low HF-RRV than males (relative risk (RR) = 1.36, 95% CI: 1.07-1.73), an association only seen among those exposed to fetal risk (RR = 1.38, 95% CI: 1.04-1.83). Findings suggest that these are shared fetal antecedents to the comorbidity of MDD and CVD risk 40 years later, an association stronger in females than in males.

Prenatal influenza exposure and cardiovascular events in adulthood

Objectives

This study examined the association between prenatal exposure to pandemic influenza and cardiovascular events in adulthood.

Design

Using Danish surveillance data to identify months when influenza activity was highest during three previous pandemics (1918, 1957, and 1968), persons were defined as exposed/unexposed based on whether they were in utero during peak months of one of the pandemics. Episodes of acute myocardial infarction (MI) and stroke were identified in the Danish National Registry of Patients covering all Danish hospitals since 1977.

Setting/Sample

Information from Danish national registries on all persons with a Civil Personal Registry number and birthdates in 1915 through 1922, 1954 through 1960, and 1966 through 1972 was collected.

Main outcome measures

Crude incidence rate ratios (IRRs) were calculated per pandemic. Generalized linear models were fit to estimate IRRs adjusted for sex.

Results

For acute MI, sex-adjusted IRRs for persons in utero during peaks of the 1918, 1957, and 1968 pandemics, compared with those born afterward, were 1·02 (95% confidence interval (CI): 0·99, 1·05), 0·96 (95% CI: 0·87, 1·05), and 1·18 (95% CI: 0·96, 1·45), respectively. For stroke, the corresponding IRRs were 0·99 (95% CI: 0·97, 1·02), 0·99 (95% CI: 0·92, 1·05), and 0·85 (95% CI: 0·77, 0·94), respectively.

Conclusions

There was generally no evidence of an association between prenatal influenza exposure and acute MI or stroke in adulthood. However, survivor bias and left truncation of outcomes for the 1918 pandemic are possible, and the current young ages of persons included in the analyses for the 1957 and 1968 pandemics may warrant later re-evaluation.

Prematurity and low weight at birth as new conditions predisposing to an increased cardiovascular risk

Although the survival rate for preterm subjects has improved considerably, due to the progress in the field of perinatal medicine, preterm birth is frequently the cause underlying a series of notorious complications: morphological, neurological, ophthalmological, and renal alterations. In addition, it has recently been demonstrated how low gestational age and reduced foetal growth contribute towards an increased cardiovascular risk in preterm neonates. In fact, cardiovascular mortality is higher among former preterm adults than those born at term. This condition is referred to as cardiovascular perinatal programming. In the light of the above, an early, constant, and prolonged cardiological followup programme should be implemented in former preterm individuals. The aim of this paper was to perform a comprehensive literature review about two new emerging conditions predisposing to an increased cardiovascular risk: prematurity and low weight at birth.

Comments on dietary restriction, Okinawa diet and longevity

Longevity in Okinawa is considered to be a result of traditional low calorie diet. Le Bourg suggests that Okinawa is an example of severe malnutrition, which is harmful for later generations. We believe that current loss of longevity advantage in Okinawa is a result of diet westernization and that the dietary restriction is a valid way of life extension in humans.