Racial disparities in the association of foetal growth retardation to childhood blood pressure

Association Analysis in Children Born from Normal and Complicated Pregnancies-Cardiovascular Disease Associated microRNAs and the Incidence of Prehypertension/Hypertension, Overweight/Obesity, Valve Problems and Heart Defects

The goal was to assess how a history of any kind of pregnancy-related complication altered expression profile of microRNAs played a role in the pathogenesis of diabetes, cardiovascular and cerebrovascular diseases in the peripheral blood leukocytes of children at the age of 3–11 years. The prior exposure to gestational hypertension, preeclampsia, fetal growth restriction, gestational diabetes mellitus, preterm prelabor rupture of membranes or spontaneous preterm birth causes that a significant proportion of children (57.42% to 90.0% specifically) had a substantially altered microRNA expression profile, which might be the origin of a lifelong cardiovascular risk. A total of 23 out of 29 tested microRNAs were upregulated in children born from such complicated gestation. The occurrence of overweight, obesity, valve problems and heart defects even intensified upregulation of microRNAs already present in children exposed to such pregnancy complications. The occurrence of overweight/obesity (miR-92a-3p, and miR-210-3p) and valve problems or heart defects (miR-342-3p) induced microRNA upregulation in children affected with pregnancy complications. Overall, 42.86% overweight/obese children and 27.36% children with valve problems or heart defects had even higher microRNA levels than children with normal clinical findings after complicated pregnancies. In addition, the microRNA expression profile was also able to differentiate between children descending from normal gestation in relation to the occurrence of overweight and obesity. Screening on the base of the combination of 19 microRNAs identified 70.0% overweight/obese children at 90.0% specificity. In general, children after complicated pregnancies, just as children after normal pregnancies, with abnormal findings are at a higher risk of the onset of cardiovascular complications, and their dispensarization, with the aim to implement primary prevention strategies, would be beneficial.

In utero exposure to gestational diabetes mellitus and cardiovascular risk factors in youth: A longitudinal analysis in the EPOCH cohort

OBJECTIVE

To examine associations of maternal gestational diabetes mellitus (GDM) with offspring cardiovascular biomarkers from late childhood through adolescence.

METHODS

We used mixed effects linear regression models to examine associations of maternal GDM (n = 92 cases of 597) with average offspring levels of serum lipids (total cholesterol, high-density lipoprotein [HDL], low-density lipoprotein [LDL], and triglycerides) and systolic blood pressure (SBP) across two research visits spanning approximately 10.6 and 16.9 years of age. In sex-stratified analysis, we evaluated the impact of adjustment for sociodemographic characteristics, pubertal status, physical activity and total energy intake, maternal body mass index (BMI), GDM treatment, and child's BMI.

RESULTS

After adjusting for child's age, pubertal status, race/ethnicity, and maternal education and smoking, GDM exposure was associated with higher total (0.38 [95% CI, 0.16-0.61] mmol/L) and LDL cholesterol (0.34 [95% CI, 0.14-0.53] mmol/L) in girls. These estimates were robust to adjustment for lifestyle characteristics and maternal BMI but were attenuated after accounting for GDM treatment with no appreciable change following further adjustment for current BMI. In boys, maternal GDM corresponded with 4.50 (1.90-7.10) mmHg higher SBP. This association persisted after accounting for sociodemographic/lifestyle characteristics, maternal BMI, and GDM treatment but was attenuated after adjusting for current BMI.

CONCLUSIONS

Maternal GDM is related to offspring lipid profile and SBP in a sex-specific manner.

Conflicting Effects of Fetal Growth Restriction on Blood Pressure Between Human and Rat Offspring: A Meta-Analysis

Low birth weight is associated with hypertension. Low birth weight can result from fetal growth restriction (FGR) or prematurity. FGR is postulated to impact blood pressure (BP) by developmental programming. This systematic review and meta-analysis studies BP in human and animal offspring following FGR. Pubmed and Web of Science were searched for studies reporting on BP after placental insufficiency induced FGR compared with normal growth controls. Primary outcome was mean absolute BP difference (ΔBP mm Hg [95% CI]). Meta-analysis was performed using random-effects models. Subgroup analyses were executed on species, sex, age, pregnancy duration, and stress during BP readings. Due to large interspecies heterogeneity, analyses were performed separately for human (n=41) and animal (n=31) studies, the latter restricted to rats (n=27). Human studies showed a ΔBP between FGR and controls of -0.6 mm Hg ([95% CI, -1.7 to 0.6]; I²=91%). Mean ΔBP was -2.6 mm Hg (95% CI, -5.7 to 0.4) in women versus -0.5 mm Hg (95% CI, -3.7 to 2.7) in men. Subgroup analyses did not indicate age, gestational age, and stress during measurements as sources of heterogeneity. In rats, mean BP was 12.0 mm Hg ([95% CI, 8.8-15.2]; I²=81%) higher in FGR offspring. This difference was more pronounced in FGR males (13.6 mm Hg [95% CI, 10.3-17.0] versus 9.1 mm Hg [95% CI, 5.3-12.8]). Subgroup analyses on age showed no statistical interaction. BP readings under restrained conditions resulted in larger BP differences between FGR and control rats (15.3 mm Hg [95% CI, 11.6-18.9] versus 5.7 mm Hg [95% CI, 1.1-10.3]). Rat studies confirm the relation between FGR and offspring BP, while observational studies in humans do not show such differences. This may be due to the observational nature of human studies, methodological limitations, or an absence of this phenomenon in humans. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: CRD42018091819.

Effect of passive exposure to cigarette smoke on blood pressure in children and adolescents: a meta-analysis of epidemiologic studies

Background

Hypertension is an emerging disease in children and adolescents resulting in future morbidities. Cigarette smoking is one of the most studied contributing factors in this regard; however, there are contradictory results among different studies. Therefore, the present meta-analysis tends to assess the relationship between passive exposure to cigarette smoke and blood pressure in children and adolescents.

Method

Medline, Embase, Scopus, EBSCO, and Web of Sciences were systematically reviewed for observational studies up to May, 2017, in which the relationship between cigarette smoking and hypertension were assessed in children and adolescents. The meta-analysis was performed with a fixed effect or random effects model according to the heterogeneity.

Results

Twenty-nine studies were included in present meta-analysis incorporating 192,067 children and adolescents. Active smoking (pooled OR = 0.92; 95% CI: 0.79 to 1.05) or passive exposure to cigarette smoke (pooled OR = 1.01; 95% CI: 0.93 to 1.10) were not associated with developing hypertension in the study population. Despite the fact that active cigarette smoking did not significantly affect absolute level of systolic and diastolic blood pressure, it was shown that passive exposure to cigarette smoke leads to a significant increase in absolute level of systolic blood pressure (pooled coefficient = 0.26; 95% CI: 0.12 to 0.39).

Conclusion

Both active and passive cigarette smoking were not associated with developing hypertension in children and adolescents. However, passive cigarette smoke was associated with higher level of systolic blood pressure in children and adolescents.

Postnatal Expression Profile of microRNAs Associated with Cardiovascular and Cerebrovascular Diseases in Children at the Age of 3 to 11 Years in Relation to Previous Occurrence of Pregnancy-Related Complications

Children descending from pregnancies complicated by gestational hypertension (GH), preeclampsia (PE) or fetal growth restriction (FGR) have a lifelong cardiovascular risk. The aim of the study was to verify if pregnancy complications induce postnatal alterations in gene expression of microRNAs associated with cardiovascular/cerebrovascular diseases. Twenty-nine microRNAs were assessed in peripheral blood, compared between groups, and analyzed in relation to both aspects, the current presence of cardiovascular risk factors and cardiovascular complications and the previous occurrence of pregnancy complications with regard to the clinical signs, dates of delivery, and Doppler ultrasound examination. The expression profile of miR-21-5p differed between controls and children with a history of uncomplicated pregnancies with abnormal clinical findings. Abnormal expression profile of multiple microRNAs was found in children affected with GH (miR-1-3p, miR-17-5p, miR-20a-5p, miR-21-5p, miR-23a-3p, miR-26a-5p, miR-29a-3p, miR-103a-3p, miR-125b-5p, miR-126-3p, miR-133a-3p, miR-146a-5p, miR-181a-5p, miR-195-5p, and miR-342-3p), PE (miR-1-3p, miR-20a-5p, miR-20b-5p, miR-103a-3p, miR-133a-3p, miR-342-3p), and FGR (miR-17-5p, miR-126-3p, miR-133a-3p). The index of pulsatility in the ductus venosus showed a strong positive correlation with miR-210-3p gene expression in children exposed to PE and/or FGR. Any of changes in epigenome (up-regulation of miR-1-3p and miR-133a-3p) that were induced by pregnancy complications are long-acting and may predispose children affected with GH, PE, or FGR to later development of cardiovascular/cerebrovascular diseases. Novel epigenetic changes (aberrant expression profile of microRNAs) appeared in a proportion of children that were exposed to GH, PE, or FGR. Screening of particular microRNAs may stratify a highly risky group of children that might benefit from implementation of early primary prevention strategies.

Developmental Origins and Nephron Endowment in Hypertension

Primary hypertension continues to be one of the main risk factors for cardiovascular disease worldwide. A stable intrauterine environment is critical for the future development and health of the fetus. The developing kidney has been found to be especially vulnerable during this time period, and epidemiological studies have demonstrated that an adverse in utero environment is associated with an increased risk of hypertension and chronic kidney disease. Macro- and micronutrient deficiencies as well as exposure to tobacco, alcohol, and certain medications during gestation have been shown to negatively impact nephrogenesis and reduce one's nephron number. In 1988, Brenner et al. put forth the controversial hypothesis that a reduced nephron complement is a risk factor for hypertension and chronic kidney disease in adulthood. Since then numerous animal and human studies have confirmed this relationship demonstrating that there is an inverse association between blood pressure and nephron number. As our understanding of the developmental programming of hypertension and other non-communicable diseases improves, more effective preventive health measures can be developed in the future.

Perinatal low-protein diet alters brainstem antioxidant metabolism in adult offspring

BACKGROUND AND OBJECTIVES

Studies in humans and animal models have established a close relationship between early environment insult and subsequent risk of development of non-communicable diseases, including the cardiovascular. Whereas experimental evidences highlight the early undernutrition and the late cardiovascular disease relation, the central mechanisms linking the two remain unknown. Owing to the oxidative balance influence in several pathologies, the aim of the present study was to evaluate the effects of maternal undernutrition (i.e. a low-protein (LP) diet) on oxidative balance in the brainstem.

METHODS AND RESULTS

Male rats from mothers fed with an LP diet (8% casein) throughout the perinatal period (i.e. gestation and lactation) showed 10× higher lipid peroxidation levels than animals treated with normoprotein (17% casein) at 100 days of age. In addition, we observed the following reductions in enzymatic activities: superoxide dismutase, 16%; catalase, 30%; glutathione peroxidase, 34%; glutathione-S-transferase, 51%; glutathione reductase, 23%; glucose-6-phosphate dehydrogenase, 31%; and in non-enzymatic glutathione system, 46%.

DISCUSSION

This study is the first to focus on the role of maternal LP nutrition in oxidative balance in a central nervous system structure responsible for cardiovascular control in adult rats. Our data observed changes in oxidative balance in the offspring, therefore, bring a new concept related to early undernutrition and can help in the development of a new clinical strategy to combat the effects of nutritional insult. Wherein the central oxidative imbalance is a feasible mechanism underlying the hypertension risk in adulthood triggered by maternal LP diet.

Vitamin D deficiency in the pathogenesis of hypertension: still an unsettled question

Vitamin D deficiency is inversely associated with blood pressure and is felt to contribute to the genesis and maintenance of hypertension. Although well demonstrated in animal studies, in many clinical studies the association between vitamin D status and blood pressure has not been consistently observed or else has been quite small. These discrepancies may relate in part to methodological differences including: patient selection, study size and duration, and, in the case of vitamin D repletion studies, differences in the vitamin D supplement used, its dose, and dosing intervals. Polymorphisms in genes regulating vitamin D activation and function may explain some of the observed inconsistencies as suggested by recent studies. The present review examines experimental and clinical studies bearing on the inverse association between blood pressure and vitamin D status and concludes that a new definition of vitamin D deficiency using additional biomarkers may better select patients with hypertension who will respond to vitamin D supplementation.

Race-specific relationship of birth weight and renal function among healthy young children

BACKGROUND

Low birth weight is associated with diminished renal function. However, despite African Americans being at increased risk of low birth weight and chronic kidney disease, little is known about the association between birth weight and renal function in diverse groups. We examined racial differences in the relationship of birth weight and renal function among healthy young children.

METHODS

Birth weight and serum creatinine data were available on 152 children (61.8% African American; 47.4% female) from a birth cohort. Estimated glomerular filtration rate (eGFR) was calculated using the bedside Schwartz equation and gender- and gestational-age-adjusted birth weight Z-scores using the US population as a reference. Race-specific linear regression models were fit to estimate the association between birth weight Z-score and eGFR.

RESULTS

Mean age was 1.5  ±  1.3 years at first eGFR measurement. African Americans had lower eGFR than non-African Americans (median eGFR = 82 vs. 95 ml/min per 1.73 m(2); p = 0.06). Birth weight was significantly and positively associated with eGFR among African American (p = 0.012) but not non-African American children (p = 0.33).

CONCLUSIONS

We provide, for the first time, evidence suggesting that birth weight is associated with renal function in African American children. Future work is needed to determine if prenatal programming helps explain racial disparities in adult health.

Prenatal programming-effects on blood pressure and renal function

Impaired intrauterine nephrogenesis-most clearly illustrated by low nephron number-is frequently associated with low birthweight and has been recognized as a powerful risk factor for renal disease; it increases the risks of low glomerular filtration rate, of more rapid progression of primary kidney disease, and of increased incidence of chronic kidney disease or end-stage renal disease. Another important consequence of impaired nephrogenesis is hypertension, which further amplifies the risk of onset and progression of kidney disease. Hypertension is associated with low nephron numbers in white individuals, but the association is not universal and is not seen in individuals of African origin. The derangement of intrauterine kidney development is an example of a more general principle that illustrates the paradigm of plasticity during development-that is, that transcription of the genetic code is modified by epigenetic factors (as has increasingly been documented). This Review outlines the concept of prenatal programming and, in particular, describes its role in kidney disease and hypertension.

Vitamin D, blood pressure, and African Americans: toward a unifying hypothesis

Vitamin D deficiency has increasingly been recognized in the general population and especially in African Americans whose deep skin pigmentation makes vitamin D photosynthesis inefficient. Over the last decade there has been increasing interest in the role that vitamin D deficiency may play in BP modulation because many epidemiologic studies have shown an inverse association between serum vitamin D concentration and BP. There is a high prevalence of vitamin D deficiency in African Americans who also have an increased susceptibility to develop hypertension and its consequences. This paper will review the circumstances leading to vitamin D deficiency in the African American population and will also discuss how vitamin D deficiency can affect the renin-angiotensin system, free radical production, inflammatory processes, and carbohydrate tolerance that in turn influence vascular endothelial function and vascular structure producing increased vascular resistance. It will speculate that the presence of vitamin D deficiency throughout life from its earliest phases may adversely affect the microvasculature in African Americans, thereby playing a major role in the genesis and maintenance of hypertension.

Recommendations for the assessment and reporting of multivariable logistic regression in transplantation literature

Multivariable logistic regression is an important method to evaluate risk factors and prognosis in solid organ transplant literature. We aimed to assess the quality of this method in six major transplantation journals. Eleven analytical criteria and four documentation criteria were analyzed for each selected article that used logistic regression. A total of 106 studies (6%) out of 1,701 original articles used logistic regression analyses from January 1, 2005 to January 1, 2006. The analytical criteria and their respective reporting percentage among the six journals were: Linearity (25%); Beta coefficient (48%); Interaction tests (19%); Main estimates (98%); Ovefitting prevention (84%); Goodness-of-fit (3.8%); Multicolinearity (4.7%); Internal validation (3.8%); External validation (8.5%). The documentation criteria were reported as follows: Selection of independent variables (73%); Coding of variables (9%); Fitting procedures (49%); Statistical program (65%). No significant differences were found among different journals or between general versus subspecialty journals with respect to reporting quality. We found that the report of logistic regression is unsatisfactory in transplantation journals. Because our findings may have major consequences for the care of transplant patients and for the design of transplant clinical trials, we recommend a practical solution for the use and reporting of logistic regression in transplantation journals.

The relationship between birthweight and longitudinal changes of blood pressure is modulated by beta-adrenergic receptor genes: the Bogalusa Heart Study

This study examines the genetic influence of beta-adrenergic receptor gene polymorphisms (beta(2)-AR Arg16Gly and beta(3)-AR Trp64Arg) on the relationship of birthweight to longitudinal changes of blood pressure (BP) from childhood to adulthood in 224 black and 515 white adults, aged 21-47 years, enrolled in the Bogalusa Heart Study. Blacks showed significantly lower birthweight and frequencies of beta(2)-AR Gly16 and beta(3)-AR Trp64 alleles and higher BP levels and age-related trends than whites. In multivariable regression analyses using race-adjusted BP and birthweight, low birthweight was associated with greater increase in age-related trend of systolic BP (standardized regression coefficient beta = -0.09, P = .002) and diastolic BP (beta = -0.07, P = .037) in the combined sample of blacks and whites, adjusting for the first BP measurement in childhood, sex, age, and gestational age. Adjustment for the current body mass index strengthened the birthweight-BP association. Importantly, the strength of the association, measured as regression coefficients, was modulated by the combination of beta(2)-AR and beta(3)-AR genotypes for systolic (P = .042 for interaction) and diastolic BP age-related trend (P = .039 for interaction), with blacks and whites showing a similar trend in the interaction. These findings indicate that the intrauterine programming of BP regulation later in life depends on beta-AR genotypes.

The clinical importance of nephron mass

Abundant evidence supports the association between low birth weight (LBW) and renal dysfunction in humans. Anatomic measurements of infants, children, and adults show significant inverse correlation between LBW and nephron number. Nephron numbers are also lower in individuals with hypertension compared with normotension among white and Australian Aboriginal populations. The relationship between nephron number and hypertension among black individuals is still unclear, although the high incidence of LBW predicts low nephron number in this population as well. LBW, a surrogate for low nephron number, also associates with increasing BP from childhood to adulthood and increasing risk for chronic kidney disease in later life. Because nephron numbers can be counted only postmortem, surrogate markers such as birth weight, prematurity, adult height, reduced renal size, and glomerulomegaly are potentially useful for risk stratification, for example, during living-donor assessment. Because early postnatal growth also affects subsequent risk for higher BP or reduced renal function, postnatal nutrition, a potentially modifiable factor, in addition to intrauterine effects, has significant influence on long-term cardiovascular and renal health.

The influence of birthweight on arterial blood pressure of children

BACKGROUND & AIMS

This study examined the relationship between birthweight and blood pressure in childhood.

METHODS

Prospective cohort study involving 472 Brazilian children ranging in age from 5 to 8 years. Birthweight, systolic blood pressure (SBP), diastolic blood pressure (DBP), body mass index (BMI), total cholesterol and fractions (LDL-c, HDL-c), and triglycerides were determined. Total cholesterol, LDL-c, HDL-c, and triglycerides were assessed by automated enzymatic methods. Blood pressure was measured with the HDI/Pulse Wave CR-2000 equipment. Multiple regression models were used to investigate the relationship between birthweight and SBP and DBP, controlling for the following variables: gender, age, BMI, total cholesterol, triglycerides, per capita income, and maternal education.

RESULTS

When adjusting for gender and BMI, we found a systolic blood pressure increase of 2.9 (95% CI=-5.33 to -0.56) mmHg per kilogram birthweight reduction. The unadjusted association was insignificant.

CONCLUSION

Our data suggest that low birthweight is one of the factors contributing to blood pressure elevation at early ages. A way to prevent these diseases is by implementing public policies focused on good nutrition and adequate prenatal care for pregnant women.

Concepts guiding therapy for hypertension in children

Increasing attention has been focused on identifying children with prehypertension and hypertension (HTN). Obesity and low birthweight are two risk factors that predispose children to develop HTN during their childhood years or later as adults. Early onset of pre-HTN and HTN increases the lifetime risk for cardiovascular sequelae. Lifestyle modification should be part of the initial recommendations for management of all hypertensive children. In those children requiring pharmacologic therapy, the choice of medication should be guided by the etiology of HTN, the needs of the child and the risk and benefit profiles of the various drug classes. The long-term impact of antihypertensive therapy in children is not known. Concerns regarding the effects of HTN and its treatment on cognitive function are of particular importance in the growing child and warrant further study. Ongoing investigations that offer promise for innovative therapeutic approaches in the future are discussed.

Intrauterine exposure to gestational diabetes, child adiposity, and blood pressure

BACKGROUND

Intrauterine exposure to gestational diabetes mellitus (GDM) may promote offspring obesity and higher systolic blood pressure (SBP) by adolescence. Few studies have examined adiposity or SBP in younger children exposed to GDM. This study's objective was to examine associations of maternal glucose tolerance during pregnancy with offspring adiposity and SBP at age 3 years.

METHODS

We studied 1,238 mother-child pairs in Project Viva, a prospective prebirth cohort study. Exposures were maternal blood glucose following oral glucose load, and GDM confirmed by 3-h glucose tolerance test. Main child outcomes were age 3-year body mass index (BMI) z-score, the sum (SS+TR) and ratio (SS/TR) of subscapular (SS) and tricep (TR) skinfold thicknesses, and SBP. We performed adjusted multivariable analyses.

RESULTS

Fifty-one (4%) mothers had GDM. 9.3% of 3 year-old children were obese and mean (s.d.) SBP was 92 (11) mm Hg. Children exposed to GDM had higher SBP (3.2 mm Hg, 95% confidence interval (CI): 0.4, 5.9, P = 0.02) and greater adiposity when assessed by the sum of skinfolds (SS+TR 1.31 mm, 95% CI: 0.08, 2.55, P = 0.04) but not by BMI z-score (-0.08 units, 95% CI: -0.37, 0.22, P = 0.61). After additional adjustment for the sum of skinfold thicknesses (SS+TR), the relationship between GDM and SBP was attenuated and no longer significant (2.6 mm Hg, 95% CI: -0.2, 5.4, P = 0.07).

CONCLUSIONS

Children exposed to GDM have higher adiposity, which may mediate the higher SBP in these children. These findings extend to younger children the adverse effects of GDM previously found among adolescents and adults.

Ethnic differences in the association of birth weight and blood pressure: the Georgia cardiovascular twin study

BACKGROUND

African Americans (AAs) not only have higher blood-pressure levels, but also an increased risk of low weight at birth, compared with European Americans (EAs). In light of fetal programming theories, it has been suggested that ethnic differences in blood pressure originate in utero. However, most previous studies in biethnic samples have not found a significant inverse association between birth weight and blood pressure in AAs.

METHODS

In 562 EA and 465 AA adolescent twins of the Georgia Cardiovascular Twin Study, we investigated the potential ethnic difference in the association of blood pressure and birth weight, with the ability to control for potential confounding by familial factors.

RESULTS

Blood-pressure levels were significantly higher in AAs compared to EAs, independent of birth weight (P < .01). After adjustment for parental factors and body mass index, the difference in systolic blood pressure per kg birth weight was -1.1 mm Hg (95% confidence interval, -2.7 to 0.48, P = .17) in EAs, and -2.5 mm Hg (95% confidence interval, -4.7 to -0.40, P = .02) in AAs. A significant ethnic interaction was revealed in paired analysis, where the inverse association remained in AAs, but not in EAs. Associations with diastolic blood pressure were generally weaker and nonsignificant.

CONCLUSIONS

We showed that low birth weight was associated with an elevated systolic blood pressure in AAs, independent of familial factors. The results also suggest that the association between birth weight and blood pressure may be more pronounced in AAs in adolescence.

Racial disparities in the association between birth weight in the term infant and blood pressure at age 7 years: results from the collaborative perinatal project

BP has been inversely associated with birth weight in studies worldwide, but few studies have included black individuals. The US National Collaborative Perinatal Project followed 58,960 pregnant women and their resultant offspring for 7 yr. In this post hoc analysis, all term white or black children without kidney or heart disease were included (n = 29,710). The effect of birth weight and other risk factors on systolic (SBP) and diastolic BP (DBP) was evaluated at 7 yr. Mean birth weight and body mass index at 7 yr were slightly lower for black compared with white children (birth weight 3.14 +/- 0.48 versus 3.32 +/- 0.46 kg [P < 0.001]; body mass index 15.8 +/- 2.0 versus 16.3 +/- 2.0 [P < 0.001]). Compared with white mothers, black mothers were less likely to smoke (41 versus 52%), were more anemic (23 versus 7%), and were more likely to live in poverty (72 versus 39%). In linear regression, there was significant interaction between race and birth weight in predicting SBP (P = 0.002). In bivariate analysis, birth weight was positively associated with SBP (beta = 0.87) and DBP (beta = 1.14) in black children (P < 0.001) but not associated with either in white children. With maternal poverty, educational level, and anemia during pregnancy added to the model, birth weight remained a significant positive predictor of SBP (beta = 0.89, P < 0.001) in black but not in white children (beta = 0.02, P = 0.17). The association between birth weight and SBP differs between black and white children. The cause of intrauterine growth restriction-associated hypertension seems to be race sensitive; therefore, future studies of racial disparities in the "Barker hypothesis" may help in the understanding of the mechanism of fetal programming of hypertension.