The relation between birth weight and intima-media thickness in middle-aged adults

Association of High Birth Weight With Incident Heart Failure in the ARIC Study

Background

Traditional risk factors for heart failure––coronary heart disease, hypertension, diabetes mellitus, obesity, and smoking––only account for about 50% of cases. Thus, the identification of novel risk factors is of significant public health importance. As high birth weight infants are at increased risk for obesity and diabetes mellitus later in life, which are both risk factors for the development of heart failure, we sought to assess the association of high birth weight with incident heart failure in the ARIC (Atherosclerosis Risk in Communities) study.

Methods and Results

The ARIC study is a biracial prospective community‐based investigation of 15 792 individuals aged 45 to 64 years at baseline. Study participants who were born premature or born a twin were excluded from this analysis, resulting in 9820 participants who provided either their birth weight category (low, medium, high) or exact birth weight. After adjusting for differences in demographics, risk factors, and comorbidities, compared with medium birth weight, those with high birth weight had a significantly increased risk of incident heart failure (hazard ratio, 1.27; 95% CI, 1.05–1.54 [P=0.014]). The hazard for all‐cause mortality for high birth weight compared with medium birth weight was 1.16 (95% CI, 0.99–1.34; P=0.06). There was no association of high birth weight with myocardial infarction (hazard ratio, 1.06; 95% CI, 0.84–1.34 [P=0.6]).

Conclusions

High birth weight was associated with a significantly increased hazard of incident heart failure independent of traditional risk factors and a trend toward an increased hazard of death. A history of high birth weight should be ascertained in young adults for primordial prevention of heart failure and in older adults for primary prevention.

Intrauterine growth restriction results in persistent vascular mismatch in adulthood

KEY POINTS

Intrauterine growth restriction (IUGR) increases offspring risk of chronic diseases later in life, including cardiovascular dysfunction. Our prior studies suggest biventricular cardiac dysfunction and vascular impairment in baboons who were IUGR at birth because of moderate maternal nutrient reduction. The current study reveals changes in artery sizes, distensibility, and blood flow pattern in young adult IUGR baboons, which may contribute to cardiac stress. The pattern of abnormality observed suggests that vascular redistribution seen with IUGR in fetal life may continue into adulthood.

ABSTRACT

Maternal nutrient reduction induces intrauterine growth restriction (IUGR), increasing risks of chronic diseases later in life, including cardiovascular dysfunction. Using ultrasound, we determined regional blood flow, blood vessel sizes, and distensibility in IUGR baboons (8 males, 8 females, 8.8 years, similar to 35 human years) and controls (12 males, 12 females, 9.5 years). The measured blood vessels were larger in size in the males compared to females before but not after normalization to body surface area. Smaller IUGR normalized blood vessel sizes were observed in the femoral and external iliac arteries but not the brachial or common carotid arteries and not correlated significantly with birth weight. Mild decrease in distensibility in the IUGR group was seen in the iliac but not the carotid arteries without between-sex differences. In IUGR baboons there was increased carotid arterial blood flow velocity during late systole and diastole. Overall, our findings support the conclusion that region specific vascular and haemodynamic changes occur with IUGR, which may contribute to the occurrence of later life cardiac dysfunction. The pattern of alteration observed suggests vascular redistribution efforts in response to challenges in the perinatal period may persist into adulthood. Further studies are needed to determine the life course progression of these changes.

Relative intima-media thickening after preterm birth

AIM

Preterm infants are at increased risk of early arterial growth arrest and cardiovascular mortality. We assessed intima-media thickness (IMT) - an early marker of accelerated vascular ageing - in very preterm infants.

METHODS

Longitudinal cohort study of 21 very preterm and 29 term infants, all with appropriate birthweights. Intima-media thickness was assessed by M-Mode ultrasound of the aorta and carotid arteries at three occasions during a 6-month period corresponding to the third trimester of pregnancy and ending 3 months after term equivalent age.

RESULTS

No differences in absolute aortic or carotid IMT were found. However, in relation to vessel lumen diameter, the IMT switched from being narrower in preterm infants, compared with foetuses at 28 weeks of gestation, to being significantly thicker in both the aorta and carotid artery in older infants born preterm, compared with term controls of equivalent postmenstrual age. Although the aortic and carotid artery diameters increased significantly with postnatal age, IMT did not.

CONCLUSION

In relation to vessel diameter, subjects born preterm show thicker intima-media in the great arteries than infants born at term. It remains to be established whether this relative intima-media thickening persists and may be a risk marker for future cardiovascular disease.

Validity of maternal birthweight recall among Colombian children

Low birthweight and preterm birth are associated with adverse health outcomes later in life, but acquisition of accurate birthweight information is not always feasible in large epidemiological studies. We examined the validity of child birthweight and gestational age recall by mothers, and the extent to which recall bias affects associations between birthweight and childhood obesity in children from Bogotá, Colombia. We surveyed mothers of 3,202 schoolchildren aged 5-12 years about child's weight and gestational age at birth, and sociodemographic characteristics. In a subsample of 279 children, we obtained hospital birth records and extracted birthweight, gestational age, and other perinatal information. Mean birthweight (SD) was 3,106 (739) grams according to maternal recall and 2,977 (462) grams according to hospital records (difference 129 g; 95% CI = 55, 203). Thirty-three percent of mothers recalled their children's birthweights exactly as they appeared in hospital records. Mother's age and fewer years of education were each significantly associated with greater birthweight recall bias. Specificity of low birthweight (<2,500 g) and preterm birth (<37 weeks gestation) from maternal recall was 0.95 and 0.86, respectively; however, sensitivity was lower (0.66 and 0.67, respectively). Associations between recalled birthweight and BMI-for-age or overweight during school age were weaker than those with hospital record birthweight. Maternal birthweight recall 5-12 years after birth differs from hospital record birthweight by a clinically meaningful amount. Birthweight recall should be used with caution in epidemiological studies conducted in this and comparable settings. Associations between birthweight and obesity may be stronger than they appear when using recalled birthweight.

Predictors of carotid intima-media thickness and carotid plaque in young Indian adults: the New Delhi birth cohort

BACKGROUND

Carotid intima-media thickness (CIMT) and carotid plaques represent preclinical markers of atherosclerosis. We sought to describe predictors of CIMT and carotid plaques, including early life growth, in a young urban Indian cohort free of clinical cardiovascular disease (CVD).

METHODS

In 2006-2009, we performed B-mode carotid ultrasound on 600 participants (mean [SD] age 36 [1.1] years; 45% women) from the New Delhi Birth Cohort to evaluate CIMT and carotid plaques (>1mm). Height and weight were recorded at birth, 2 and 11 years of age. Data on CVD risk factors, anthropometry, medical history, socio-economic position, and lifestyle habits were collected in 1998-2002.

RESULTS

Mean (SD) CIMT for men and women was 0.91 (0.12) and 0.86 (0.13) mm, respectively. Carotid plaque was present in 33% of men and 26% of women. Waist circumference in 1998-2002 was positively associated with CIMT (β coefficient 0.26 mm [0.17, 0.36] per SD) and carotid plaque (OR 1.27 [1.06,1.52] per SD) in 2006-2009. Higher triglycerides, PAI-1, insulin resistance, and diastolic blood pressure, metabolic syndrome, and lower HDL-cholesterol and physical activity predicted higher CIMT and/or plaque (p<0.05). Longer length at 2 years was associated with higher CIMT (p<0.05). These associations were attenuated after adjusting for adult waist circumference.

CONCLUSIONS

These are the first prospective data from India showing that early life growth, adult socio-demographics, and CVD risk factors predict future CIMT and/or carotid plaque. These relationships appear primarily mediated through central adiposity, highlighting the importance of maintaining a healthy weight in early adulthood to prevent CVD.

Intima-media thickness and flow-mediated dilatation in the Helsinki study of very low birth weight adults

BACKGROUND

Adults born at a very low birth weight (VLBW) (< 1500 g), compared with those born at term, bear risk factors for cardiovascular disease, including higher blood pressure and insulin resistance.

OBJECTIVE

We studied, in young adults born at a VLBW, early signs of an accelerated atherosclerotic process and the relationship of these signs with postnatal growth.

METHODS

We compared 92 with a VLBW with 68 who were born at term. At age 18 to 27, we measured stiffness and intima-media thickness (IMT) of the right carotid artery and flow-mediated dilatation (FMD) of the right brachial artery.

RESULTS

Those with a VLBW had 1.1% units higher FMD (95% confidence interval [CI]: 0.0-2.2) (P = .06) and 0.5% units higher IMT relative to lumen size (95% CI: 0.1-0.9). IMT or FMD, when analyzed as the absolute change in millimeters, and carotid stiffness in the groups were similar. Among those with a VLBW, each 100-g-greater weight gain during the first 2 postnatal weeks predicted 1.1% units higher FMD (95% CI: 0.2-2.0) in adulthood.

CONCLUSIONS

Although young adults born at VLBWs, compared with those born at term, have higher levels of risk factors for cardiovascular disease, we found no clear evidence for elevated early markers of atherosclerosis. However, in relation to artery lumen diameter, IMT in the participants who had a VLBW was higher than in those who were born at term. In our study, weight gain during the first postnatal weeks had no harmful effect on the arteries in young adulthood.

Low birth weight and the developing vascular tree: a systematic review

Low birth weight (LBW) is a risk factor for hypertension, stroke and coronary heart disease in adults. Mechanisms underlying cardiovascular disease may therefore be initiated in early life. Studies to investigate the initiating events and emergence of vascular risk markers in infancy and childhood have been an area of particular interest in recent years. The aim of this review is to focus on the early development of the human vascular tree in relation to LBW. Specific characteristics, including endothelial function, intima-media thickness, microvascular density, arterial dimensions and elasticity, will be discussed. LBW due to different causes--poor foetal growth or preterm birth--results in different patterns of altered development of the vascular system, which can already be seen in infancy. Follow-up studies in children and young adults indicate that vascular compromise in many ways persists in those born either small for gestational age or prematurely.

CONCLUSION

LBW is associated with structural and functional changes in the vascular tree, which have implications for cardiovascular health in adult life.

Low birth weight and markers of inflammation and endothelial activation in adulthood: the ARIC study

BACKGROUND

To investigate the hypothesis that intrauterine growth restriction might produce a longstanding pro-inflammatory tendency, we investigated the association of low birth weight with blood levels of markers of inflammation and endothelial activation in middle-aged adults.

METHODS

The ARIC Study enrolled subjects aged 45-64 years sampled from four U.S. communities. An inflammation/endothelial activation score from 0 to 6 was created, one point being given for each above-median value of white blood cell count, fibrinogen, von Willebrand factor and Factor VIII, and for each below-median value of albumin and activated partial thromboplastin time.

RESULTS

Of the 9809 individuals reporting birth weight and having all inflammation/endothelial markers and covariates, 349 (3.6%) reported low birth weight (LBW). The mean (standard deviation) score was 3.5 (1.5) for those with and 3.1 (1.6) for those without LBW (p<0.001). In robust poisson regression models adjusting for gender, ethnicity, age, study center, educational level, and current drinking and smoking status and amount, those with LBW were more likely to have a high score (> or =4 points) (RR=1.16, 95% CI: 1.05-1.29).

CONCLUSION

In the ARIC Study, LBW predicted greater inflammation and endothelial activation, as indicated by the higher score of blood markers, consistent with the hypothesis that early life events may result in a hyper-responsive innate immune system. Such a pro-inflammatory tendency could help explain the association of low birth weight with elements of the metabolic syndrome and ischemic heart disease.

The relationship between birthweight and early age-related maculopathy: the atherosclerosis risk in communities study

PURPOSE

Birthweight is a marker of fetal growth, and has been linked to future risk of chronic diseases in adults. We examined the association between birthweight and age-related maculopathy (ARM).

METHODS

We studied 9730 adults from the population-based Atherosclerosis Risk in Communities study, of whom 4744 reported their exact birthweight and an additional 4986 provided categorical birthweight data (low, medium or high). We graded retinal photographs for presence of ARM using a modification of the Wisconsin ARM Grading System.

RESULTS

Early ARM was present in 479 (4.9%) adults. Among persons with exact birthweight data, there was no association between birthweight and early ARM (OR 1.1, 95% CI 0.9-1.3, for each kg increase in birthweight). However, in Whites, greater birthweight was associated with an increased risk of early ARM (OR 1.2, 95% CI 1.0-1.4, for each kilogram increase in birthweight), after adjustment for age, sex, smoking, blood pressure and education level. In analyses including additional participants who provided categorical birthweight data, the pattern of associations were similar but not statistically significant. We did not have sufficient numbers to examine associations for late ARM (n = 12) or in African-Americans separately.

CONCLUSIONS

We found no association between birthweight and risk of early ARM in the whole population. Among the white participants, higher birthweight was associated with a slight increased risk of early ARM. These findings, if confirmed in other studies, suggest that fetal growth may be important in ARM development in white persons.

Validity of maternal report on birth weight 11 years after delivery: the 1993 Pelotas Birth Cohort Study, Rio Grande do Sul State, Brazil

Birth weight has short and long-term effects on health. Some studies have used retrospective data on birth weight, reported by the subject or by the parents. This paper compares data on birth weight measured by the research team in 1993 with birth weight reported by the mother in 2004-2005, using data from the 1993 Pelotas Birth Cohort Study, Rio Grande do Sul State, Brazil. We also evaluate the role of misclassification when exploring the effect of birth weight on a given outcome. Mean difference between the two variables was 20g (SD = 288.3). Agreement for detecting low birth weight was 95.2% in the sample as a whole (kappa = 0.73), but was lower among low-schooling mothers. Mothers of children weighing less than 3,500g at birth tended to overestimate the child's birth weight. Inversely, mothers of heavier children tended to underestimate the values. One out of four mothers reported a difference of at least 200g in birth weight as compared to that measured in 1993. Use of reported birth weight diluted the magnitude of the association with body mass index at 11 years in comparison with measured birth weight. Reported birth weight should be used with great caution, if at all.

Reduced intima media thickness in adults after prenatal exposure to the Dutch famine

BACKGROUND

Restricted prenatal growth is associated with an increased risk of coronary heart disease morbidity and mortality. We studied the effects of exposure to famine during gestation on intima media thickness (IMT) in later life.

METHODS AND RESULTS

We studied 730 people aged 58 years who were born as term singletons around the time of the 1944-45 Dutch famine. Persons exposed to famine during gestation (n=293) had reduced carotid artery IMT compared to people who had not been exposed to famine in utero (n=437) (mean 0.71 mm, S.D. 0.16 mm compared to 0.75 mm, S.D. 0.15 mm, sex adjusted p=0.001). Femoral artery IMT was also thinner among people exposed to famine during gestation compared to people unexposed in utero (mean 0.64 mm, S.D. 0.20mm, compared to 0.68 mm, S.D. 0.24), although the difference did not achieve statistical significance.

CONCLUSION

Exposure to famine in utero may reduce IMT. However, it does not reduce the risk of coronary heart disease among famine exposed people.

Longitudinal study of birth weight and adult body mass index in predicting risk of coronary heart disease and stroke in women

OBJECTIVES

To determine whether birth weight and adult body size interact to predict coronary heart disease in women, as has been observed for men. To determine whether birth weight and adult body size interact to predict risk of stroke.

DESIGN

Longitudinal cohort study.

SETTING AND PARTICIPANTS

66,111 female nurses followed since 1976 who were born of singleton, term pregnancies and reported their birth weight in 1992.

MAIN OUTCOME MEASURES

1504 events of coronary heart disease (myocardial infarction or sudden cardiac death) and 1164 strokes.

RESULTS

For each kilogram of higher birth weight, age adjusted hazard ratios from prospective analysis were 0.77 (95% confidence interval 0.69 to 0.87) for coronary heart disease and 0.89 (0.78 to 1.01) for total stroke. In combined prospective and retrospective analysis, hazard ratios were 0.84 (0.76 to 0.93) for total stroke, 0.83 (0.71 to 0.96) for ischaemic stroke, and 0.86 (0.66 to 1.11) for haemorrhagic stroke. Exclusion of macrosomic infants (> 4536 g) yielded stronger estimates. Risk of coronary heart disease was especially high for women who crossed from a low centile of weight at birth to a high centile of body mass index in adulthood. The association of lower birth weight with increased risk of stroke was apparent across categories of body mass index in adults and was not especially strong among heavier women.

CONCLUSIONS

Higher body mass index in adulthood is an especially strong risk factor for coronary heart disease among women who were small at birth. In this large cohort of women, size at birth and adiposity in adulthood interacted to predict events of coronary heart disease but not stroke events.