Low birth weight and blood pressure

The association of maternal serum uric acid with the risk of small for gestational age newborn: a retrospective cohort study

PROBLEM

Prior results on the association between serum uric acid (UA) levels in the early trimester and the risk of small for gestational age (SGA) remain unclear. This study evaluated the association of maternal first-, second-, and third-trimester UA levels with the risk of SGA infants.

METHOD OF STUDY

A total of 23, 194 singleton mothers from the International Peace Maternity and Child Health Hospital between January 2014 and January 2017 were included. Maternal UA levels were measured at 12.1 ± 1.08th (UA1) and 32.2 ± 1.03th (UA2) gestational weeks. △UA was calculated as the difference between UA2 and UA1. Logistic regression and restricted cubic spline (RCS) were performed to evaluate the association between maternal UA and △UA during pregnancy and SGA. Receiver operating characteristic (ROC) analysis was employed to assess the serum uric acid prediction value.

RESULTS

Women in the higher quartiles of UA1 had a significantly higher risk of SGA. A clear increased risk for SGA was observed with higher quartiles for UA2 (p for trend <0.05). An approximately "J-shaped" relationship was observed between UA2 and △UA, and the risk of SGA was observed. When compared with those with a lower level of UA in the first trimester, those with a higher level of UA1, the more increase in the later UA levels were associated with a higher risk of SGA [adjusted odds ratio (aOR) = 1.67, 95% CI:1.37-2.05]. The ROC curve areas were 0.525 for UA1, 0.582 for UA2 and 0.576 for △UA.

CONCLUSIONS

The findings suggested that non-preeclamptic and non-hypertensive women who experienced early pregnancy with high UA levels had an elevated risk of SGA. Moreover, a high maternal UA level in the earlier trimester may be an early predictor of SGA.

Gestational weight gain and neonatal outcomes in different zygosity twins: a cohort study in Wuhan, China

OBJECTIVE

To evaluate whether twin zygosity influences the association between neonatal outcomes and gestational weight gain (GWG) based on the Chinese guidelines in twin-pregnancy women.

DESIGN

A retrospective cohort study. And it is not a clinical trial.

SETTING

Women with twin pregnancies living in Wuhan, China.

PARTICIPANTS

A total of 5140 women who delivered live and non-malformed twins from 1 January 2011 to 31 August 2017 were included in this study.

MAIN OUTCOME MEASURE

The primary neonatal outcomes included paired small for gestational age (SGA, <10 th percentile birth weight for gestational age and sex), low birth weight (LBW, <2500 g) and gestational age (<33 weeks and <37 weeks). The association between GWG and neonatal outcomes was examined by Logistic regression analyses.

RESULTS

A total of 5140 women were included, of whom 22.24%, 54.78% and 22.98% were below, within and above the Chinese guidelines, respectively. Among the including 10 280 infants, 26.28% of them were monozygotic (MZ) twins and 73.72% of them were dizygotic (DZ) twins. Women with low GWG had a significantly higher proportion of LBW/LBW and LBW/NBW infants, a greater likelihood of SGA/SGA and SGA/appropriate for gestational age (AGA) infants and a higher incidence of preterm birth. The associations persisted both in MZ and DZ twins, and twin zygosity influenced the degree of association between GWG and SGA, LBW and preterm birth. High GWG was associated with significant risk reductions in SGA/AGA pairs, LBW/LBW or LBW/NBW pairs, and less than 33 gestational weeks. However, high GWG was only associated with reduced risk of LBW/LBW pairs both in MZ and DZ twins.

CONCLUSIONS

GWG below the Chinese recommendations increased the risk of SGA, LBW and preterm birth in both MZ and DZ twins. The effect was more pronounced in MZ twins than that in DZ twin pairs. A high GWG only reduced the risk of LBW/LBW pairs both in MZ and DZ twins.

Association of preconception mixtures of phenol and phthalate metabolites with birthweight among subfertile couples

Although parental preconception exposure to some phenols and phthalates have been associated with reduced birthweight, few studies have examined these chemicals as complex mixtures.

Risk factors for left ventricular dysfunction in adulthood: role of low birth weight

Aims

This study aimed to determine the relationship of low birth weight (LBW) with adult cardiac structure and function and investigate potential causal pathways.

Methods and results

A population‐based sample of 925 Australians (41.3% male) were followed from childhood (aged 7–15 years) to young adulthood (aged 26–36 years) and mid‐adulthood (aged 36–50 years). Left ventricular (LV) global longitudinal strain (GLS, %), LV mass index (LVMi, g/m^2.7), LV filling pressure (E/e′), and left atrial volume index (g/m²) were measured by transthoracic echocardiography in mid‐adulthood. Birth weight category was self‐reported in young adulthood and classified as low (≤5 lb or ≤2270 g), normal (5–8 lb or 2271–3630 g), and high (>8 lb or >3630 g). Of the 925 participants, 7.5% (n = 69) were classified as LBW. Compared with participants with normal birth weight, those with LBW had 2.01‐fold (95% confidence interval: 1.19, 3.41, P = 0.009) higher risks of impaired GLS (GLS > −18%) and 2.63‐fold (95% confidence interval: 0.89, 7.81, P = 0.08) higher risks of LV hypertrophy (LVMi > 48 g/m^2.7 in men or >44 g/m^2.7 in women) in adulthood, independent of age, sex, and any socio‐economic factors. Participants with LBW significantly increased body fat from childhood to adulthood relative to their peers and had greater levels of triglycerides, fasting glucose, and arterial stiffness in adulthood. These risk factors were the strongest mediators and explained 54% of the LBW effect size on adult GLS and 33% of the LBW effect size on LVMi. The remaining of these associations was independent of any of the measured risk factors.

Conclusions

Low birth weight was associated with impaired cardiac structure and function in mid‐adulthood. This association was only partially explained by known risk factors.

Comparison of Genome-Wide DNA Methylation Profiles of Human Fetal Tissues Conceived by in vitro Fertilization and Natural Conception

Background

Assisted reproductive technology (ART) might induce adverse pregnancy outcomes and increase the risk of metabolic diseases in offspring' later life with unknown reasons. Here we evaluated the global methylation level and methylation profile of fetal tissue from elective terminations of pregnancy (ETP) after natural conception and multifetal pregnancy reduction (MFPR) after in vitro fertilization and embryo transfer (IVF-ET).

Results

Global methylation levels were comparable between the fetal tissue of ETP after natural conception group and MFPR after IVF-ET group. The methylation levels were lower in the hypermethylated regions of the MFPR group than in the ETP group, while the methylation levels were higher in the hypomethylated regions of the MFPR group. Heatmap visualization and hierarchical clustering of the candidate differentially methylated regions (DMRs) showed differences between the DMRs in the ETP and MFPR samples. We identified 196 differentially methylated regions that matched 164 genes between the ETP and MFPR groups. In the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses, skeletal system morphogenesis and diabetes mellitus ranked first. Ingenuity Pathway Analysis (IPA) revealed 8 diseases and functional annotations associated with IVT-ET. In the MFPR group, the final validation showed lower methylation levels in gene bodies of bone morphogenetic protein 4 (BMP4), higher methylation levels in the 1st exon and 5'UTR of thyroid peroxidase (TPO), and higher methylation levels in TSS1500 and TSS200 of interleukin 1 beta (IL1B).

Conclusions

ART does not alter global DNA methylation level, but influences DNA methylation variation in specific regions of human fetus in the early stage of life. Further studies are warranted to clarify the potential role of DNA methylation alterations in the gene expression profile.

Mendelian randomization analysis does not support causal associations of birth weight with hypertension risk and blood pressure in adulthood

Epidemiology studies suggested that low birthweight was associated with a higher risk of hypertension in later life. However, little is known about the causality of such associations. In our study, we evaluated the causal association of low birthweight with adulthood hypertension following a standard analytic protocol using the study-level data of 183,433 participants from 60 studies (CHARGE-BIG consortium), as well as that with blood pressure using publicly available summary-level genome-wide association data from EGG consortium of 153,781 participants, ICBP consortium and UK Biobank cohort together of 757,601 participants. We used seven SNPs as the instrumental variable in the study-level analysis and 47 SNPs in the summary-level analysis. In the study-level analyses, decreased birthweight was associated with a higher risk of hypertension in adults (the odds ratio per 1 standard deviation (SD) lower birthweight, 1.22; 95% CI 1.16 to 1.28), while no association was found between genetically instrumented birthweight and hypertension risk (instrumental odds ratio for causal effect per 1 SD lower birthweight, 0.97; 95% CI 0.68 to 1.41). Such results were consistent with that from the summary-level analyses, where the genetically determined low birthweight was not associated with blood pressure measurements either. One SD lower genetically determined birthweight was not associated with systolic blood pressure (β = - 0.76, 95% CI - 2.45 to 1.08 mmHg), 0.06 mmHg lower diastolic blood pressure (β = - 0.06, 95% CI - 0.93 to 0.87 mmHg), or pulse pressure (β = - 0.65, 95% CI - 1.38 to 0.69 mmHg, all p > 0.05). Our findings suggest that the inverse association of birthweight with hypertension risk from observational studies was not supported by large Mendelian randomization analyses.

Genome-wide DNA methylation changes in placenta tissues associated with small for gestational age newborns; cohort study in the Chinese population

Aim: To investigate DNA methylation changes in placenta tissues associated with small for gestational age (SGA). Materials & methods: A prospective cohort study consisting of 1292 pregnant women from China (including 39 SGA with placenta tissues) was performed, microarray and pyrosequencing were conducted. Results: Total 2012 methylation variable positions stood out from all probes (p < 0.05; Δβ > 0.2). In SGA cases, a CpG site within ANKRD20B showed lower methylation level (p = 0.032) than appropriate for gestational age in validation cohort. Five sites within FAM198A (p = 0.047, 0.050, 0.039, 0.026 and 0.043, respectively) had a reduced methylation in male newborns whose mother had preconception folic acid supplementation. Conclusion: DNA methylation changes in placenta tissues may be associated with SGA, maternal preconception folic acid supplementation status and also be fetal sex-specific.

Renal injury after uninephrectomy in male and female intrauterine growth-restricted aged rats

Epidemiological studies report an inverse association between birth weight and risk for kidney disease that may differ between males and females, but studies investigating this association are limited. This study tested the hypothesis that male intrauterine growth-restricted offspring in a model of low birth weight induced by placental insufficiency in the rat exhibit enhanced renal injury in response to a persistent secondary renal insult while female growth-restricted offspring are protected. For this study, control offspring from sham-operated dams and growth-restricted offspring from reduced uterine perfusion dams underwent uninephrectomy or a sham procedure at 18 months of age. One month later, urinary markers of renal injury, renal function, and histological damage were measured. Results were analyzed using 2-way ANOVA. Male and female offspring were assessed separately. Proteinuria and urinary neutrophil gelatinase-associated lipocalin were significantly elevated in male growth-restricted offspring exposed to uninephrectomy when compared to male uninephrectomized control. Urinary kidney injury marker-1 was elevated in male uninephrectomized growth-restricted offspring relative to male sham growth-restricted but not to male uninephrectomized controls. Likewise, urinary neutrophil gelatinase-associated lipocalin was elevated in female uninephrectomized growth-restricted offspring but only when compared to female sham growth-restricted offspring. Markers of renal function including glomerular filtration rate and serum creatinine were impaired after uninephrectomy in female offspring regardless of birth weight. Histological parameters did not differ between control and growth-restricted offspring. Collectively, these studies suggest that both male and female growth-restricted offspring demonstrate susceptibility to renal injury following uninephrectomy; however, only male growth-restricted offspring exhibited an increase in renal markers of injury in response to uninephrectomy relative to same-sex control counterparts. These findings further suggest that urinary excretion of protein, kidney injury marker-1, and neutrophil gelatinase-associated lipocalin may be early markers of kidney injury in growth-restricted offspring exposed to a secondary renal insult such as reduction in renal mass.

A Systematic Review of Placental Biomarkers Predicting Small-for-Gestational-Age Neonates

Background:

Neonates born small for gestational age (SGA) face increased risk of neonatal mortality, childhood developmental problems, and adult disease. The placenta is a key factor in SGA development because of its multiple biological processes that underlie fetal growth. However, valid and reliable placental biomarkers of SGA have not been determined.

Objectives:

The objective of this article was to systematically identify and review studies examining associations between placental biomarkers and SGA and assess those biomarkers’ predictive value.

Methods:

Use of the matrix method and the PRISMA guidelines ensured systematic identification of relevant articles based on selection criteria. PubMed, CINAHL, and EMBASE were searched for English articles published in 2005–2016 that addressed relationships between placental biomarkers and SGA.

Results:

The search captured 466 articles; 13 met selection criteria. The review identified 14 potential placental biomarkers for SGA, with placental growth factor and soluble fms-like tyrosine kinase 1 being the most commonly studied. However, findings for these and other biomarkers have often been contradictory. Thus, no placental biomarkers have been confirmed as reliable for predicting SGA.

Conclusion:

The inconsistent findings suggest low placental biomarker reliability, perhaps due to the multifactorial nature of SGA. This review is novel in its focus on identifying potential placental biomarkers for SGA, producing a better understanding of how placental function underlies fetal growth. Nevertheless, use of placental biomarkers alone may not be adequate for predicting SGA. Therefore, combinations of biomarkers and other predictive tests should be evaluated for their ability to predict risk of SGA.

Early growth and changes in blood pressure during adult life

Previous studies suggest that the inverse association between birth weight and adult blood pressure amplifies with age. Rapid childhood growth has also been linked to hypertension. The objective of this study was to determine whether the association between childhood growth and adult blood pressure amplifies with age. The study comprised 574 women and 462 men from the Helsinki Birth Cohort Study who attended a clinical study in 2001–2004 and a follow-up in 2006–2008. Mean age at the clinic visits was 61.5 and 66.4 years, respectively. Blood pressure was measured at both occasions. Conditional growth models were used to assess relative weight gain and linear growth. We studied the associations between conditional growth and blood pressure as well as the presence of hypertension. Relative weight gain and linear growth between ages 2 and 11 years were inversely associated with systolic blood pressure at mean age 66.4 years, after adjustment for sex, blood pressure at mean age 61.5 years, as well as other covariates. A one s.d. increase in linear growth between 2 and 11 years was associated with an OR of 0.61 for hypertension at mean age 66.4 years. Contrary to previous studies, we have shown an inverse association between childhood growth and adult blood pressure. There were, however, no associations between childhood growth and systolic blood pressure at mean age 61.5 years indicating that the beneficial effects of a more rapid than expected childhood growth might become more apparent with increasing age.

Effects of Birth Weight on Anterior Segment Measurements in Full-Term Children Without Low Birth Weight by Dual-Scheimpflug Analyzer

PURPOSE

To evaluate the effects of birth weight on ocular anterior segment parameters in full-term children without low birth weight using the Galilei Dual-Scheimpflug Analyzer.

DESIGN

Retrospective cohort study.

METHODS

The right eyes from 110 healthy children, 3-6 years of age, were scanned with the Galilei Dual-Scheimpflug Analyzer. A total of 78 eyes were measured in full-term children with birth weight of >2500 g. Central, paracentral, pericentral, and the thinnest corneal thicknesses; anterior and posterior keratometry (average, steep, flat); axial curvatures; asphericity of cornea; anterior chamber depth and volume; and iridocorneal angle values were measured. Axial length, lens thickness, and vitreous length were obtained by ultrasound biometry.

RESULTS

The mean age of children was 55.86 ± 12.52 (mean ± SD) months. Mean birth weight and gestational age were 3426.3 ± 545 g and 39.4 ± 1.2 weeks, respectively. Although lens thickness, vitreous length, axial length, and anterior chamber volume were moderately correlated with birth weight (P < .05), there was no relationship between birth weight and anterior chamber depth. With the exception of pericentral corneal thickness, all regions of corneal thicknesses were correlated with birth weight (P < .05). Birth weight was negatively correlated with anterior curvature (P < .05) and had no relationship to posterior curvature. While central and paracentral axial curvatures correlated with birth weight (P < .05), pericentral axial curvature did not.

CONCLUSION

Preschoolers who were born heavier had thicker cornea and lens, longer axial length, and flatter corneal curve. The thicknesses and axial curves of central cornea within 7 mm may be particularly associated with birth weight.

Cord blood immune biomarkers in small for gestational age births

Fetal growth restriction is a risk factor for development of adulthood diseases, but the biological mechanism of this association remains unknown. Limited biomarkers have been studied in settings of preterm birth and maternal inflammation, but the relationship between a wide range of immune biomarkers and fetal growth has not been studied. The hypothesis of this study was that fetal growth restriction is associated with altered immune biomarker levels. We examined the relationship between small for gestational age (SGA) status and 27 umbilical cord blood immune biomarkers. This study was part of a large-scale cohort study of preterm birth and low birth weight conducted at Boston Medical Center, an inner city, predominantly minority patient population. Growth status was determined based on birth weight standardized to an internal reference. There were 74 SGA births and 319 appropriate for age (AGA) births with complete clinical and biomarker data. Adjusting for covariates and using AGA as reference, SGA births had lower levels of log IL-1β (ng/l; β -0.38, 95% CI -0.57, -0.19, P < 0.01), log BDNF (β -0.29, 95% CI -0.55, -0.03, P < 0.05) and log NT-3 (β -0.46, 95% CI -0.77, -0.15, P < 0.01). No associations were found between other biomarkers and SGA. In conclusion, three biomarkers were selectively associated with SGA status. Our results provide information that could be used to guide additional studied aimed at determining mechanisms that contribute to fetal growth.

Cardiac and vascular disease prior to hatching in chick embryos incubated at high altitude

The partial contributions of reductions in fetal nutrition and oxygenation to slow fetal growth and a developmental origin of cardiovascular disease remain unclear. By combining high altitude with the chick embryo model, we have previously isolated the direct effects of high-altitude hypoxia on growth. This study isolated the direct effects of high-altitude hypoxia on cardiovascular development. Fertilized eggs from sea-level or high-altitude hens were incubated at sea level or high altitude. Fertilized eggs from sea-level hens were also incubated at high altitude with oxygen supplementation. High altitude promoted embryonic growth restriction, cardiomegaly and aortic wall thickening, effects which could be prevented by incubating eggs from high-altitude hens at sea level or by incubating eggs from sea-level hens at high altitude with oxygen supplementation. Embryos from high-altitude hens showed reduced effects of altitude incubation on growth restriction but not on cardiovascular remodeling. The data show that: (1) high-altitude hypoxia promotes embryonic cardiac and vascular disease already evident prior to hatching and that this is associated with growth restriction; (2) the effects can be prevented by increased oxygenation; and (3) the effects are different in embryos from sea-level or high-altitude hens.

Renal denervation abolishes the age-dependent increase in blood pressure in female intrauterine growth-restricted rats at 12 months of age

Perinatal insults program sex differences in blood pressure, with males more susceptible than females. Aging may augment developmental programming of chronic disease, but the mechanisms involved are not clear. We previously reported that female growth-restricted offspring are normotensive after puberty. Therefore, we tested the hypothesis that age increases susceptibility to hypertension in female growth-restricted offspring. Blood pressure remained similar at 6 months of age; however, blood pressure was significantly elevated in female growth-restricted offspring relative to control by 12 months of age (137±3 vs 117±4 mm Hg; P<0.01, respectively). Body weight did not differ at 6 or 12 months of age; however, total fat mass and visceral fat were significantly increased at 12 months in female growth-restricted offspring (P<0.05 vs control). Glomerular filtration rate remained normal, yet renal vascular resistance was increased at 12 months of age in female growth-restricted offspring (P<0.05 vs control). Plasma leptin, which can increase sympathetic nerve activity, did not differ at 6 months but was increased at 12 months of age in female growth-restricted offspring (P<0.05 vs control). Because of the age-dependent increase in leptin, we hypothesized that the renal nerves may contribute to the age-dependent increase in blood pressure. Bilateral renal denervation abolished the elevated blood pressure in female growth-restricted offspring normalizing it relative to denervated female control offspring. Thus, these data indicate that age induces an increase in visceral fat and circulating leptin associated with a significant increase in blood pressure in female growth-restricted offspring, with the renal nerves serving as an underlying mechanism.

New loci associated with birth weight identify genetic links between intrauterine growth and adult height and metabolism

Birth weight within the normal range is associated with a variety of adult-onset diseases, but the mechanisms behind these associations are poorly understood. Previous genome-wide association studies of birth weight identified a variant in the ADCY5 gene associated both with birth weight and type 2 diabetes and a second variant, near CCNL1, with no obvious link to adult traits. In an expanded genome-wide association meta-analysis and follow-up study of birth weight (of up to 69,308 individuals of European descent from 43 studies), we have now extended the number of loci associated at genome-wide significance to 7, accounting for a similar proportion of variance as maternal smoking. Five of the loci are known to be associated with other phenotypes: ADCY5 and CDKAL1 with type 2 diabetes, ADRB1 with adult blood pressure and HMGA2 and LCORL with adult height. Our findings highlight genetic links between fetal growth and postnatal growth and metabolism.

Metabolic Syndrome in Adolescence

Background—

There are well-established predisposing factors for the development of metabolic syndrome (MetS) in childhood or adolescence, but no specific risk profile has been identified as yet. The Prediction of Metabolic Syndrome in Adolescence (PREMA) study was conducted (1) to construct a classification score that could detect children at high risk for MetS in adolescence and (2) to test its predictive accuracy.

Methods and Results—

In the derivation cohort (1270 children), data from natal and parental profile and from initial laboratory assessment at 6 to 8 years of age were used to detect independent predictors of MetS at 13 to 15 years of age according to the International Diabetes Federation definition. In the validation cohort (1091 adolescents), the discriminatory capacity of the derived prediction score was tested on an independent adolescent population. MetS was diagnosed in 105 adolescents in the derivation phase (8%), whereas birth weight <10th percentile (odds ratio, 6.02; 95% confidence interval, 2.53–10.12, P <0.001), birth head circumference <10th percentile (odds ratio, 4.15; 95% confidence interval, 2.04–7.14, P <0.001), and parental overweight or obesity (in at least 1 parent; odds ratio, 3.22; 95% confidence interval, 1.30–5.29, P <0.01) were independently associated with diagnosis of MetS in adolescence. Among adolescents in the validation cohort (86 [8%] with MetS), the presence of all these 3 predictors predicted MetS with a sensitivity of 91% and a specificity of 98%.

Conclusions—

The coexistence of low birth weight, small head circumference, and parental history of overweight or obesity may be useful for detection of children at risk of developing MetS in adolescence.

Consequences in infants that were intrauterine growth restricted

Intrauterine growth restriction is a condition fetus does not reach its growth potential and associated with perinatal mobility and mortality. Intrauterine growth restriction is caused by placental insufficiency, which determines cardiovascular abnormalities in the fetus. This condition, moreover, should prompt intensive antenatal surveillance of the fetus as well as follow-up of infants that had intrauterine growth restriction as short and long-term sequele should be considered.

Legg-Calve-Perthes disease and risks for cardiovascular diseases and blood diseases

OBJECTIVE

We hypothesized that patients with Legg-Calvé-Perthes disease (LCPD) might have higher risks of cardiovascular and blood diseases.

METHODS

A total of 3141 patients, 2 to 15 years of age, with LCPD diagnosed between 1965 and 2005 were identified with the Swedish Inpatient Register. A total of 15 595 individuals without LCPD were selected randomly from among the Swedish general population, with matching according to year of birth, age, gender, and region of residence. Cox proportional-hazard regression analyses, with adjustment for socioeconomic index, were used to estimate relative risks. The patients also were compared with their same-gender siblings.

RESULTS

Patients with LCPD had a hazard ratio (HR) of 1.70 (95% confidence interval [CI]: 1.39-2.09) for cardiovascular diseases, compared with individuals without LCPD. The point estimate was slightly higher among subjects >30 years of age at the follow-up (HR: 2.10 [95% CI: 1.52-2.91]). There were statistically significantly higher risks for blood diseases, including anemias and coagulation defects (HR: 1.41 [95% CI: 1.07-1.86]), which were more pronounced among subjects >30 years of age at the follow-up (HR: 2.70 [95% CI: 1.50-4.84]). Patients also had statistically significantly higher risks of hypertensive disease (HR: 2.97 [95% CI: 1.87-4.72]) and nutritional anemia (HR: 2.92 [95% CI: 1.58-5.40]). Analyses using siblings as the comparison group showed consistent results for cardiovascular diseases.

CONCLUSION

The results are consistent with the hypothesis that an insufficient blood supply to the femoral head, attributable to vascular pathologic conditions, is involved in the pathogenesis of LCPD.

Early life origins of low-grade inflammation and atherosclerosis risk in children and adolescents

OBJECTIVE

To examine the relationship between birth weight and later low-grade inflammation in children and adolescents.

STUDY DESIGN

We selected 166 children (49.4% boys; aged, 9.5 +/- 0.3 years) and 126 adolescents (43.7% males; aged, 15.5 +/- 0.4 years) from the Swedish part of the European Youth Heart Study. Birth weight data were collected from parental recall. Low-grade inflammatory markers include C-reactive protein, fibrinogen, and complement factors C3 and C4. Fatness was measured by the sum of 5 skinfold thicknesses. Cardiorespiratory fitness was measured with a maximal ergometer bike test. The association between birth weight and low-grade inflammatory markers was examined with multiple regression analyses.

RESULTS

Birth weight was negatively associated with fibrinogen (beta = -0.059; P = .036), C3 (beta = -0.019; P = .010), and C4 (beta = -0.024; P = .031), after controlling for sex, pubertal status, mother's body mass index and socioeconomic status, fatness and fitness. Birth weight was not associated to later C-reactive protein level (all P > .1).

CONCLUSIONS

Our results showed that smaller birth weight is associated with chronic low-grade inflammation in children and adolescents. Because of the implication of complement factors on atherosclerosis process, these results contribute to explain the increased cardiovascular risk associated with low birth weight.

Impact of genetic and epigenetic factors from early life to later disease

There is ample evidence that subtle changes in the early environment, not restricted to the fetal period but expanded to the plastic phase of early development, influence adulthood disease appearance. There is also evidence that genetic background resulting from our evolution is an important contributor to susceptibility to perinatal imprinting. However, rapid adjustment and optimization, at times necessary for survival, require a type of plasticity that the genome sequence alone cannot achieve. Without changing the genomic backbone, epigenetic modulation, in reaction to a given environment, results in functional adaptation of the genomic response. Evolutionally acquired genomic susceptibilities and environmentally induced epigenomic modulations occurring early in life impact on later development of human diseases.