Birth weight and blood pressure in childhood: results from the Health Survey for England

Longitudinal study of birthweight, blood pressure, and markers of arterial stiffness in children age six among the TIDES cohort

OBJECTIVE

Although some studies have observed an association between birthweight and cardiovascular disease in adulthood, fewer have investigated whether birthweight is linked to cardiovascular health in early childhood. This study assesses the association between birthweight and cardiovascular outcomes in children 6 years of age.

STUDY DESIGN

Birthweight, blood pressure (BP), and markers of arterial stiffness in children, including brachial artery distensibility and carotid-femoral pulse wave velocity (cfPWV), were obtained from 324 participants in The Infant Development and the Environment Study, a prospective multisite pregnancy cohort. Birthweight was converted into sex-specific birthweight-for-gestational-age (bw/ga) z -scores based on the INTERGROWTH-21st standard. Following 2017 American Academy of Pediatrics guidelines, SBP and DBP were transformed into sex, age, and height-specific z -scores. Associations between birthweight and cardiovascular outcomes were assessed using nested multivariable linear regression models among the overall and sex-stratified samples.

RESULTS

Among the overall sample, bw/ga z -score was positively associated with cfPWV [b = 0.11 m/s, 95% confidence interval (CI): 0.01 m/s, 0.21 m/s] in crude and adjusted models. No associations between birthweight and cardiovascular outcomes were detected among the sex-stratified analyses.

CONCLUSION

Overall, birthweight was not related to cardiovascular outcomes in children 6 years old. However, infants born with a higher birthweight may be at risk for higher cfPWV in childhood. Early intervention in pregnant people at risk of delivering high birthweight infants may be warranted if results are replicated.

Vascular tone regulation in renal interlobar arteries of male rats is dysfunctional after intrauterine growth restriction

Intrauterine growth restriction (IUGR) due to an adverse intrauterine environment predisposes to arterial hypertension and loss of kidney function. Here, we investigated whether vascular dysregulation in renal interlobar arteries (RIAs) may contribute to hypertensive glomerular damage after IUGR. In rats, IUGR was induced by bilateral uterine vessel ligation. Offspring of nonoperated rats served as controls. From postnatal day 49, blood pressure was telemetrically recorded. On postnatal day 70, we evaluated contractile function in RIAs and mesenteric arteries. In addition, blood, urine, and glomerular parameters as well as renal collagen deposition were analyzed. IUGR RIAs not only showed loss of stretch activation in 9 of 11 arteries and reduced stretch-induced myogenic tone but also showed a shift of the concentration-response relation of acetylcholine-induced relaxation toward lower concentrations. However, IUGR RIAs also exhibited augmented contractions through phenylephrine. Systemic mean arterial pressure [mean difference: 4.8 mmHg (daytime) and 5.7 mmHg (night)], mean glomerular area (IUGR: 9,754 ± 338 µm² and control: 8,395 ± 227 µm²), and urinary protein-to-creatinine ratio (IUGR: 1.67 ± 0.13 g/g and control: 1.26 ± 0.10 g/g) were elevated after IUGR. We conclude that male IUGR rat offspring may have increased vulnerability toward hypertensive glomerular damage due to loss of myogenic tone and augmented endothelium-dependent relaxation in RIAs.NEW & NOTEWORTHY For the first time, our study presents wire myography data from renal interlobar arteries (RIAs) and mesenteric arteries of young adult rat offspring after intrauterine growth restriction (IUGR). Our data indicate that myogenic tone in RIAs is dysfunctional after IUGR. Furthermore, IUGR offspring suffer from mild arterial hypertension, glomerular hypertrophy, and increased urinary protein-to-creatinine ratio. Dysregulation of vascular tone in RIAs could be an important variable that impacts upon vulnerability toward glomerular injury after IUGR.

Factors Associated with Primary Hypertension in Pediatric Patients: An Up-to-Date

BACKGROUND

Arterial hypertension in children is considered a common alteration nowadays, mainly because obesity is a growing worldwide problem closely related to increased blood pressure. Childhood hypertension can be classified as primary or secondary, depending on the etiology. Primary or essential hypertension still has its pathophysiology not fully elucidated, and there is no consensus in the literature on most underlying mechanisms. In this review, genetic and environmental factors, including sodium and potassium intake, socioeconomic status, ethnicity, family structure, obesity, sedentary lifestyle, prematurity and low birth weight, prenatal and postnatal exposures are highlighted.

OBJECTIVE

The present study aimed to perform an update on primary hypertension in childhood, providing clinicians and researchers an overview of the current state of the literature regarding the influence of genetic and environmental factors.

METHODS

This integrative review searched for articles on genetic and environmental factors related to primary hypertension in pediatric patients. The databases evaluated were PubMed and Scopus.

RESULTS

The studies have provided insights regarding many genetic and environmental factors, in addition to their association with the pathophysiology of primary hypertension in childhood. Findings corroborated the idea that primary hypertension is a multifactorial disease. Further studies in the pediatric population are needed to elucidate the underlying mechanisms.

CONCLUSION

The study of primary hypertension in pediatrics has utmost importance for the adoption of preventive measures and the development of more efficient treatments, therefore reducing childhood morbidity and the incidence of cardiovascular diseases and other health consequences later in life.

Early Determinants of Childhood Blood Pressure at the Age of 6 Years: The GECKO Drenthe and ABCD Study Birth Cohorts

Background

There is still uncertainty about the nature and relative impact of early determinants on childhood blood pressure. This study explored determinants of blood pressure at the age of 6 years in 2 Dutch birth cohorts.

Methods and Results

Results of hierarchical multiple linear regression analyses in GECKO (Groningen Expert Center for Kids With Obesity) Drenthe study (n=1613) were replicated in ABCD (Amsterdam Born Children and Their Development) study (n=2052). All analyses were adjusted for child's age, sex, height, and body mass index (BMI), and maternal education and subsequently performed in the combined sample. No associations were found between maternal smoking during pregnancy and childhood blood pressure. In the total sample, maternal prepregnancy BMI was positively associated with systolic blood pressure (SBP) (β [95% CI], 0.09 [0.02–0.16] mm Hg) and diastolic blood pressure (β [95% CI], 0.11 [0.04–0.17] mm Hg). Children of women with hypertension had higher SBP (β [95% CI], 0.98 [0.17–1.79] mm Hg). Birth weight standardized for gestational age was inversely associated with SBP (β [95% CI], −6.93 [−9.25 to −4.61] mm Hg) and diastolic blood pressure (β [95% CI], −3.65 [−5.70 to −1.61] mm Hg). Longer gestational age was associated with lower SBP (β [95% CI] per week, −0.25 [−0.42 to −0.08] mm Hg). Breastfeeding for 1 to 3 months was associated with lower SBP (β [95% CI], −0.96 [−1.82 to −0.09] mm Hg) compared with no or <1 month of breastfeeding. Early BMI gain from the age of 2 to 6 years was positively associated with SBP (β [95% CI], 0.41 [0.08–0.74] mm Hg) and diastolic blood pressure (β [95% CI], 0.37 [0.07–0.66] mm Hg), but no effect modification by birth weight was found.

Conclusions

Higher maternal prepregnancy BMI, maternal hypertension, a relatively lower birth weight for gestational age, shorter gestational age, limited duration of breastfeeding, and more rapid early BMI gain contribute to higher childhood blood pressure at the age of 6 years.

Blood Pressure Trajectories from Childhood to Adolescence in Pediatric Hypertension

It has been known for a long time that elevated blood pressure (BP) in the young may persist and progress into adult hypertension (HTN). Multiple studies have revealed the predicted BP trajectory lines starting from childhood and related them to later cardiovascular (CV) risks in adulthood. As a small baby grows into a tall adult, BP will also naturally increase. Among early-life predictors of adult HTN, birth history, such as prematurity, and low birth weight have been popular subjects in research on pediatric HTN, because body size at birth has been reported to be inversely related to the risk of adulthood HTN. The hypothesis of HTN in prematurely born adolescents has been postulated as a physiological predisposition to postnatal excessive weight gain. Current body weight is a well-known independent predictor of HTN in children, and some studies showed that children demonstrating upward crossing of their weight percentiles while growing into adolescents have significantly increased risk for elevated BP later in life. Recently, reports focused on the adverse effect of excessive catch-up growth in this population are gradually drawing attention. Accordingly, children born prematurely or with intrauterine growth restriction who show rapid changes in their weight percentile should be under surveillance with BP monitoring. Prevention of childhood obesity, along with special care for premature infants or infants small for their gestational age, by providing healthy nutritional guidelines should be cardinal strategies for the prevention of adult HTN and CV risks later in life.

Birth weight and adolescent blood pressure measured at age 12 years in the Gateshead Millennium Study

Birth weight and early growth have been associated with later blood pressure. However, not all studies consistently find a significant reduction in blood pressure with an increase in birth weight. In addition, the relative importance of birth weight and of other lifestyle and environmental factors is often overlooked and the association is rarely studied in adolescents. We investigated early life predictors, including birth weight, of adolescent blood pressure in the Gateshead Millennium Study (GMS). The GMS is a cohort of 1029 individuals born in 1999-2000 in Gateshead in Northern England. Throughout infancy and early childhood, detailed information were collected, including birth weight and measures of height and weight. Assessments of 491 returning participants at age 12 years included measures of body mass and blood pressure. Linear regression and path analysis were used to determine predictors and their relative importance on blood pressure. Birth weight was not directly associated with blood pressure at the age of 12. However, after adjustment for contemporaneous body mass index (BMI), an inverse association of standardized birth weight on systolic blood pressure was significant. The relative importance of birth weight on later systolic blood pressure was smaller than other contemporaneous body measures (height and BMI). There was no independent association of birth weight on blood pressure seen in this adolescent population. Contemporaneous body measures have an important role to play. Lifestyle factors that influence body mass or size, such as diet and physical activity, where interventions are directed at early prevention of hypertension should be targeted.

Developmental Programming of Renal Function and Re-Programming Approaches

Chronic kidney disease affects more than 10% of the population. Programming studies have examined the interrelationship between environmental factors in early life and differences in morbidity and mortality between individuals. A number of important principles has been identified, namely permanent structural modifications of organs and cells, long-lasting adjustments of endocrine regulatory circuits, as well as altered gene transcription. Risk factors include intrauterine deficiencies by disturbed placental function or maternal malnutrition, prematurity, intrauterine and postnatal stress, intrauterine and postnatal overnutrition, as well as dietary dysbalances in postnatal life. This mini-review discusses critical developmental periods and long-term sequelae of renal programming in humans and presents studies examining the underlying mechanisms as well as interventional approaches to "re-program" renal susceptibility toward disease. Clinical manifestations of programmed kidney disease include arterial hypertension, proteinuria, aggravation of inflammatory glomerular disease, and loss of kidney function. Nephron number, regulation of the renin-angiotensin-aldosterone system, renal sodium transport, vasomotor and endothelial function, myogenic response, and tubuloglomerular feedback have been identified as being vulnerable to environmental factors. Oxidative stress levels, metabolic pathways, including insulin, leptin, steroids, and arachidonic acid, DNA methylation, and histone configuration may be significantly altered by adverse environmental conditions. Studies on re-programming interventions focused on dietary or anti-oxidative approaches so far. Further studies that broaden our understanding of renal programming mechanisms are needed to ultimately develop preventive strategies. Targeted re-programming interventions in animal models focusing on known mechanisms will contribute to new concepts which finally will have to be translated to human application. Early nutritional concepts with specific modifications in macro- or micronutrients are among the most promising approaches to improve future renal health.

Association between high birth weight and hypertension in children and adolescents: a cross-sectional study in China

This study aims to examine the relationship between high birth weight (HBW) and blood pressure and assess whether HBW leads to increased hypertension during childhood and adolescence. All the participants aged 6-18 years with HBW were selected from a cross-sectional study from seven provinces in China. Nine thousand nine hundred and sixty-two children were randomly sampled with matched data. Basic information of students was collected with a standardized student and guardian questionnaire. High blood pressure was defined according to sex-, age- and height-specific references. Multi-variance logistic regression was used to estimate the odds ratio (OR) of high blood pressure and HBW after adjustment for confounding factors. The overall mean of systolic BP and diastolic BP in HBW group were significantly higher than normal group in both genders and urban/rural area. Corresponding overall prevalence of high BP, elevated SBP and elevated DBP in HBW group were also higher than normal group in both genders, respectively (boys: 19.41% vs 16.16%; 10.12% vs 8.16%; 14.86% vs 12.71%; girls: 14.95% vs 12.66%; 8.19% vs 6.56%; 11.13% vs 9.86%). In addition, birth weight was positively associated with high BP, elevated SBP and elevated DBP in children and adolescents of both sexes (boys: OR 1.25, 1.27, 1.20; girls: OR 1.21, 1.27, 1.15). However, the positive association was attenuated and even reversed after adjustment for potential confounding variables. In this study, HBW may lead to higher childhood blood pressure, but no association between HBW and childhood hypertension was observed.

Postnatal height and adiposity gain, childhood blood pressure and prehypertension risk in an Asian birth cohort

OBJECTIVE

There have been hypotheses that early life adiposity gain may influence blood pressure (BP) later in life. We examined associations between timing of height, body mass index (BMI) and adiposity gains in early life with BP at 48 months in an Asian pregnancy-birth cohort.

METHODS

In 719 children, velocities for height, BMI and abdominal circumference (AC) were calculated at five intervals [0-3, 3-12, 12-24, 24-36 and 36-48 months]. Triceps (TS) and subscapular skinfold (SS) velocities were calculated between 0-18, 18-36 and 36-48 months. Systolic (SBP) and diastolic blood pressure (DBP) was measured at 48 months. Growth velocities at later periods were adjusted for growth velocities in preceding intervals, as well as measurements at birth.

RESULTS

After adjusting for confounders and child height at BP measurement, each unit z-score gain in BMI, AC, TS and SS velocities at 36-48 months were associated with 2.3 (95% CI:1.6, 3.1), 2.1 (1.3, 2.8), 1.4 (0.6, 2.2) and 1.8 (1, 2.6) mmHg higher SBP respectively, and 0.9 (0.4, 1.4), 0.9 (0.4, 1.3), 0.6 (0.1, 1.1) and 0.8 (0.3, 1.3) mmHg higher DBP respectively. BMI and adiposity velocities (AC, TS or SS) at various intervals in the first 36 months however, were not associated with BP. Faster BMI, AC, TS and SS velocities, but not height, at 36-48 months were associated with 0.22 (0.15, 0.29), 0.17 (0.10, 0.24), 0.11 (0.04, 0.19) and 0.15 (0.08, 0.23) units higher SBP z-score respectively, and OR=1.46 (95% CI: 1.13-1.90), 1.49 (1.17-1.92), 1.45 (1.09-1.92) and 1.43 (1.09, 1.88) times higher risk of prehypertension/hypertension respectively at 48 months.

CONCLUSIONS

Our results indicated that faster BMI and adiposity (AC, TS or SS) velocities only at the preceding interval before 48 months (36-48 months), but not at earlier intervals in the first 36 months, are predictive of BP and prehypertension/hypertension at 48 months.

Gender differences in developmental programming of cardiovascular diseases

Hypertension is a risk factor for cardiovascular disease, the leading cause of death worldwide. Although multiple factors contribute to the pathogenesis of hypertension, studies by Dr David Barker reporting an inverse relationship between birth weight and blood pressure led to the hypothesis that slow growth during fetal life increased blood pressure and the risk for cardiovascular disease in later life. It is now recognized that growth during infancy and childhood, in addition to exposure to adverse influences during fetal life, contributes to the developmental programming of increased cardiovascular risk. Numerous epidemiological studies support the link between influences during early life and later cardiovascular health; experimental models provide proof of principle and indicate that numerous mechanisms contribute to the developmental origins of chronic disease. Sex has an impact on the severity of cardiovascular risk in experimental models of developmental insult. Yet, few studies examine the influence of sex on blood pressure and cardiovascular health in low-birth weight men and women. Fewer still assess the impact of ageing on sex differences in programmed cardiovascular risk. Thus, the aim of the present review is to highlight current data about sex differences in the developmental programming of blood pressure and cardiovascular disease.

Circulating insulin-like growth factor-binding protein 3 levels, independent of insulin-like growth factor 1, associate with truncal fat and systolic blood pressure in South Asian and white European preschool children

AIMS

To study the effect of the insulin-like growth factor (IGF) system on growth, adiposity and systolic blood pressure (SBP) in early life in British-born South Asian (SA) and White European (WE) children.

METHODS

The effect of IGF-1 and insulin-like growth factor-binding protein 3 (IGFBP-3) over the first 4 years in 204 healthy SA and WE children was investigated by mixed linear regression modelling. This enabled inclusion of all follow-up observations and adjustment for repeated measures.

RESULTS

At birth, SA babies were shorter and lighter than WE babies. Over 4 years, SA ethnicity was associated with lower height, weight and body mass index (BMI) standard deviation score (SDS), higher subscapular/triceps skinfold thickness (Ss/Tr SFT) and lower SBP (all p < 0.01). IGF-1 was associated with greater height (p = 0.03), weight (p < 0.001) and BMI SDS (p < 0.001), and IGFBP-3 with greater weight SDS (p < 0.001), BMI SDS (p = 0.001), Ss/Tr SFT (p = 0.003) and SBP (p = 0.023).

CONCLUSIONS

Over this first 4-year period of life, SA ethnicity was associated with being shorter, lighter, having more superficial truncal adiposity and lower SBP. IGFBP-3 (and not IGF-1) was independently associated with both superficial truncal adiposity and SBP, suggesting that IGFBP-3 is a potential metabolic and cardiovascular marker in healthy children in the early years of life.

The effect of abnormal birth history on ambulatory blood pressure and disease progression in children with chronic kidney disease

OBJECTIVE

To examine the associations between abnormal birth history (birth weight <2500 g, gestational age <36 weeks, or small for gestational age), blood pressure (BP), and renal function among 332 participants (97 with abnormal and 235 with normal birth history) in the Chronic Kidney Disease in Children Study, a cohort of children with chronic kidney disease (CKD).

STUDY DESIGN

Casual and 24-hour ambulatory BP were obtained. Glomerular filtration rate (GFR) was determined by iohexol disappearance. Confounders (birth and maternal characteristics, socioeconomic status) were used to generate predicted probabilities of abnormal birth history for propensity score matching. Weighted linear and logistic regression models with adjustment for quintiles of propensity scores and CKD diagnosis were used to assess the impact of birth history on BP and GFR.

RESULTS

Age at enrollment, percent with glomerular disease, and baseline GFR were similar between the groups. Those with abnormal birth history were more likely to be female, of Black race or Hispanic ethnicity, to have low household income, or part of a multiple birth. Unadjusted BP measurements, baseline GFR, and change in GFR did not differ significantly between the groups; no differences were seen after adjusting for confounders by propensity score matching.

CONCLUSIONS

Abnormal birth history does not appear to have exerted a significant influence on BP or GFR in this cohort of children with CKD. The absence of an observed association is likely secondary to the dominant effects of underlying CKD and its treatment.

Current growth status and metabolic parameters of Korean adolescents born small for gestational age: results from the Korea National Health and Nutrition Examination Surveys (KNHANES) 2010-2011

BACKGROUND

Currently, little information is available on current growth status and metabolic syndrome (MetS) components according to birthweight at gestational age (BWGA) on Korean adolescents. Herein, the current height and weight and MetS components of Korean adolescents who were born as small for gestational age (SGA) were compared to those of the appropriate for GA (AGA) or large for GA (LGA) groups.

METHODS

Data for 2018 adolescents (aged 10-18 years) recorded in the Fifth Korean National Health and Nutrition Examination Survey 2010-2011 conducted by the Korean Ministry of Health and Welfare were assessed in this cross-sectional study. A total of 1750 subjects were assessed for current growth according to BWGA, and 792 were assessed for MetS components according to BWGA.

RESULTS

From the birth history of 1750 adolescents, the prevalence of SGA, AGA, and LGA was 11.4% (n = 193), 77.7% (n = 1366), and 10.9% (n = 191), respectively. Current height-standard deviation score (SDS) and weight-SDS were significantly positively related to BWGA in all Korean adolescents (P < 0.0001). Of the 792 adolescents, the prevalence of MetS was 1.2% (n = 9). There were no differences in MetS components in Korean adolescents between SGA and AGA or LGA group.

CONCLUSION

BWGA is related to current height and weight in Korean adolescents but is not related to individual components of MetS.

Hypertension in the teenager

Over the last two decades, essential hypertension has become common in adolescents, yet remains under-diagnosed in absence of symptoms. Diagnosis is based on normative percentiles that factor in age, sex and height. Evaluation is more similar to adult essential hypertension than childhood secondary hypertension. Modifiable risk factors such as obesity, sodium consumption and low exercise should be addressed first. Many anti-hypertensive medications now have specific regulatory approval for children. Sports participation need not be limited in mild or well-controlled cases. Primary care physicians play an important role in reduction of cardiovascular mortality by early detection and referral when needed.

Birth weight and childhood blood pressure

A large body of literature suggests an inverse relationship between birth weight and blood pressure in children, adolescents and adults. The most persistent findings have been observed in children with a history of low birth weight or intrauterine growth restriction, while a large number of studies carried out in populations with normally distributed birth weight have shown conflicting results. A recently reported strong direct association between high birth weight and blood pressure, and the significant positive effect of postnatal growth on blood pressure suggests that the fetal origins of adult disease hypothesis should be expanded to include the role of excessive fetal and postnatal growth. In this paper, we review recent studies on the relationship between birth weight and blood pressure in childhood, with a focus on confounding variables that may explain the conflicting results of published work in this field.

Enhanced post-natal growth is associated with elevated blood pressure in young Senegalese adults

BACKGROUND

Evidence suggests that intrauterine growth restriction followed by rapid post-natal growth is associated with high blood pressure. We assessed the effect of early size and post-natal growth on blood pressure in a population from West Africa, where fetal growth retardation and childhood malnutrition are common.

METHODS

A total of 1288 Senegalese subjects were followed from infancy to young adulthood (mean age 17.9 years). Adult systolic blood pressure (SBP) was regressed on infant and adult anthropometric characteristics.

RESULTS

In unadjusted analyses, infant size was positively associated with adult SBP (1.1 +/- 0.3; P = 0.001 for weight; 0.7 +/- 0.3; P = 0.04 for length). With adjustment for current size, the regression coefficients for infant size were reversed (-0.2 +/- 0.3; P = 0.51 for weight; -0.3 +/- 0.3; P = 0.35 for length). SBP increased by 4.1 and 2.9 mmHg for 1 standard deviation (SD) increase in current weight or height, respectively. No interaction between infant size and current size was found in the overall models (P = 0.11 for weight, P = 0.95 for height), but this term interacted with sex for weight effect. A negative interaction was found in males (-0.9 +/- 0.4; P = 0.02) but not in females (0.3 +/- 0.4; P = 0.46). The association of current weight with SBP was stronger in lighter weight male infants.

CONCLUSIONS

These findings support the hypothesis that subjects who were small in early life and experienced enhanced post-natal growth have higher levels of SBP, even in low-income settings.

The Relationship of Low Birth Weight to Blood Pressure, Cortisol Levels, and Reactivity in African American Adolescents: A Pilot Study

Epidemiological studies show a relationship between low birth weight (LBW) and adult cardiovascular disease. Blood pressure and cortisol hyper-responsiveness during physiologic stress may function as biological markers for hypertension. The purpose of this study was to explore the relationship of blood pressure and cortisol levels with induced physiologic stress to LBW. Forty-eight adolescents, 14 to 16 years old, were tested for blood pressure and cortisol levels at rest and in response to a physiological stressor. A history of LBW was obtained. Multivariate repeated measures analysis and chi-square analyses were used to determine the changes in blood pressure and cortisol.Forty-eight African American adolescents, mean age 14.98 years (SD = 0.33), completed the study. Thirteen adolescents (27%) reported LBW. Although not statistically significant, systolic and diastolic pressures were 6 mmHg and 2 mmHg, respectively, higher in the LBW group when compared with the normal birth weight (NBW) group (p = 0.33 and p = 0.21, and 6 (46%) had elevated blood pressures (p = 0.005)). Blood pressure changes, cardiovascular reactivity, elevated blood, or all of these were significantly higher in LBW African American adolescents (p = 0.006). Cardiovascular reactivity was not significant (p = 0.208)). The mean average cortisol levels were (18.8 nmol/dL (SD = 11.0) but comparable (p = 0.72)). The number of LBW adolescents with cortisol reactivity was significantly higher that in the NBW group (p = 0.041). This study adds support to the association of LBW to biological markers of hypertension in childhood.

Blood pressure levels in childhood: probing the relative importance of birth weight and current size

Several studies have reported data supporting the idea that an impaired intrauterine environment that deprives the fetus of optimal nutrient delivery results in the predisposition of the fetus to experience cardiovascular and metabolic dysfunction in later life. However, contradictory data still exist. Our purpose was to investigate the effects of both birth weight and weight gain on the risk for high blood pressure levels in 6- to 10-year-old children. This cross-sectional study included 739 children divided into quartiles of birth weight. The mean values of both systolic and diastolic pressure were significantly different between quartiles of birth weight, with increasing blood pressure values as the birth weight decreased (P<0.001). Covariance analysis adjusting for gender, prematurity, and body mass index (BMI) showed that both systolic and diastolic pressure remained greater in the lowest than in the highest birth weight quartile. Separating those with low and normal birth weight demonstrated that the risk of childhood hypertension was significantly higher among children with low birth weight and current obesity (odds ratio [OR]: 5.0, confidence interval [CI]: 3.3 to 16.1; P=0.023). The inverse association between birth weight and blood pressure levels appears to be programmed during fetal life, while weight gain during childhood adds to this risk.

The association of low birth weight and physiological risk factors of hypertension in African American adolescents

Low birth weight (LBW) has been associated with increased blood pressure and the development of cardiovascular disease including hypertension. Elevated blood pressure, cortisol, and hyperresponsiveness during physiologic stress may function as hypertension biological markers. We examined the association of blood pressure and cortisol levels during induced physiologic stress with LBW in an African American adolescent population (n = 106).

METHODS AND RESULTS

Birth weight was obtained from parents. Blood pressure and cortisol levels were measured at rest and in response to an induced physiological stressor. Compared with normal birth weight group (n = 73), the LBW group (n = 33) demonstrated elevated (+4 mm Hg) diastolic pressure (P = .002) and cortisol hyperresponsiveness (P = .05). Seventy-nine percent of LBW adolescents had elevated blood pressure and/or cardiovascular reactivity (P = .04), and 39% had elevated blood pressures.

CONCLUSIONS

Low birth weight African American adolescents demonstrated physiological risk factors for hypertension, and these findings add support to the association between LBW and the development of hypertension.

Early renal denervation prevents development of hypertension in growth-restricted offspring

1. Low birth weight is associated with an increased risk for the development of hypertension. Our laboratory uses a model of reduced uterine perfusion in the pregnant rat that results in intrauterine growth-restricted (IUGR) offspring that develop hypertension at a prepubertal age. Although hypertension develops in both prepubertal male and female IUGR offspring, only male IUGR offspring remain hypertensive after puberty. We reported previously that bilateral renal denervation abolishes hypertension in adult male IUGR offspring, indicating an important role for the renal nerves in the maintenance of established IUGR-induced hypertension. We also reported that angiotensin-converting enzyme inhibition abolishes hypertension in adult male IUGR offspring. However, activation of the renin-angiotensin system does not occur in male IUGR offspring until after puberty, or after the development of established IUGR-induced hypertension. Therefore, the mechanisms involved in the development of IUGR-induced hypertension may differ from those involved in the maintenance of established IUGR-induced hypertension. Thus, the purpose of the present study was to determine whether the renal nerves play a causative role in the early development of IUGR-induced hypertension in prepubertal IUGR offspring. 2. Intrauterine growth-restricted and control offspring were subjected to either bilateral renal denervation or sham denervation, respectively, at 4 weeks of age. Mean arterial pressure (MAP) was determined at 6 weeks of age in conscious, chronically instrumented animals. Adequacy of renal denervation was verified by renal noradrenaline content. 3. Whereas renal denervation had no effect on MAP in control offspring (103 +/- 2 vs 102 +/- 3 mmHg for sham vs denervated, respectively), it reduced blood pressure in growth-restricted offspring (114 +/- 3 vs 104 +/- 1 mmHg for sham vs denervated, respectively; P < 0.01). Renal noradrenaline content was significantly reduced in denervated animals relative to sham operated rats. 4. Thus, the data indicate a role for the renal nerves in the aetiology of IUGR-induced hypertension and suggest that the renal nerves may participate in the early development of hypertension in IUGR offspring in addition to established hypertension observed in adult male IUGR offspring.

Maternal nutrition, low nephron number, and hypertension in later life: pathways of nutritional programming

A large body of epidemiologic literature supports an inverse relation between birth weight and both systolic blood pressure and prevalence of hypertension, but mechanisms through which lower birth weight increases risk for hypertension are not established. This article advances the view that 1) permanently reduced nephron number is essential but not alone sufficient to mediate nutritionally induced hypertension; and 2) fetally programmed propensity for increased appetite and accelerated postnatal growth, thus generating inappropriately increased body mass, is a necessary "second hit" to actualize hypertension vulnerability. Based on decades of nephrologic research, this increased ratio of body mass (excretory load) to nephron number (excretory capacity) induces intrarenal compensations (tubular and glomerular hypertrophy with single-nephron hyperfiltration and intrarenal renin-angiotensin II activation), which maintain normal glomerular filtration rate at the expense of systemic and glomerular hypertension and at the risk of progressive renal disease. The vigor of the intrarenal compensatory responses is markedly greater in the immature than in the mature kidney, potentially explaining the greater risk of nephron deficits being present early in life as compared with the minimal risk in adult kidney donors. Effective interventions have not yet been defined. Suboptimal maternal nutrition, pervasive in both developed and developing countries, offers a window of opportunity to enhance the cardiovascular and renal health of future generations.

Management of the child born small for gestational age through to adulthood: a consensus statement of the International Societies of Pediatric Endocrinology and the Growth Hormone Research Society

OBJECTIVE

Low birth weight remains a major cause of morbidity and mortality in early infancy and childhood. It is associated with an increased risk of health problems later in life, particularly coronary heart disease and stroke. A meeting was convened to identify the key health issues facing a child born small for gestational age (SGA) and to propose management strategies.

PARTICIPANTS

There were 42 participants chosen for their expertise in obstetrics, peri- and neonatal medicine, pediatrics, pediatric and adult endocrinology, epidemiology, and pharmacology.

EVIDENCE

Written materials were exchanged, reviewed, revised, and then made available to all. This formed the basis for discussions at the meeting. Where published data were not available or adequate, discussion was based on expert clinical opinions.

CONSENSUS PROCESS

Each set of questions was considered by all and then discussed in plenary sessions with consensus and unresolved issues identified. The consensus statement was prepared in plenary sessions and then edited by the group chairs and shared with all participants.

CONCLUSIONS

The diagnosis of SGA should be based on accurate anthropometry at birth including weight, length, and head circumference. We recommend early surveillance in a growth clinic for those without catch-up. Early neurodevelopment evaluation and interventions are warranted in at-risk children. Endocrine and metabolic disturbances in the SGA child are recognized but infrequent. For the 10% who lack catch-up, GH treatment can increase linear growth. Early intervention with GH for those with severe growth retardation (height sd score, <-2.5; age, 2-4 yr) should be considered at a dose of 35-70 microg/kg x d. Long-term surveillance of treated patients is essential. The associations at a population level between low birth weight, including SGA, and coronary heart disease and stroke in later life are recognized, but there is inadequate evidence to recommend routine health surveillance of all adults born SGA outside of normal clinical practice.

Testosterone contributes to marked elevations in mean arterial pressure in adult male intrauterine growth restricted offspring

Our laboratory uses a model of intrauterine growth restriction (IUGR) induced by placental insufficiency in the rat to examine the developmental origins of adult disease. In this model only male IUGR offspring remain hypertensive in adulthood, revealing sex-specific differences. The purpose of this study was to determine whether testosterone with participation of the renin-angiotensin system (RAS) contributes to hypertension in adult male IUGR offspring. At 16 wk of age a significant increase in testosterone (346 +/- 34 vs. 189 +/- 12 ng/dl, P < 0.05) was associated with a significant increase in mean arterial pressure (MAP) measured by telemetry in IUGR offspring (147 +/- 1 vs. 125 +/- 1 mmHg, P < 0.05, IUGR vs. control, respectively). Gonadectomy (CTX) at 10 wk of age significantly reduced MAP by 16 wk of age in IUGR offspring (124 +/- 2 mmHg, P < 0.05 vs. intact IUGR) but had no effect in control (125 +/- 2 mmHg). A significant decrease in MAP in intact IUGR (111 +/- 3 mmHg, P < 0.05 vs. untreated intact IUGR) and castrated IUGR (110 +/- 4 mmHg, P < 0.05 vs. untreated CTX IUGR) after treatment with enalapril for 2 wk suggests a role for RAS involvement. However, the decrease in blood pressure in response to enalapril was greater in intact IUGR (Delta36 +/- 1 mmHg, P < 0.05) compared with CTX IUGR (Delta15 +/- 2 mmHg), indicating an enhanced response to RAS blockade in the presence of testosterone. Thus these results suggest that testosterone plays a role in modulating hypertension in adult male IUGR offspring with participation of the RAS.

Hypertension in children and adolescents

Hypertension is one of the most common health problems in the United States and a powerful independent risk factor for cardiovascular and renal disease. Until recently, the incidence of persistent hypertension in children has been low, with a range of 1% to 3%. Recent data indicate that over the last decade, however, average blood pressure levels have risen substantially among American children. Obesity and other lifestyle factors, such as physical inactivity and increased intake of high-calorie, high-salt foods, are thought to be responsible for this trend. Hypertension in children is currently recognized as an important health issue. There is increasing evidence that hypertension has its antecedents during childhood, because adult blood pressure often correlates with childhood blood pressure. Hypertension in children also is viewed as a significant risk factor for the development of cardiovascular disease in adulthood.