Association between size at birth, truncal fat and obesity in adult life and its contribution to blood pressure and coronary heart disease; study in a high birth weight population

The impact of maternal and paternal birth weights on infant birth weights: the Japan environment and children's study

This study aimed to evaluate the association between parental and infant birth weights in Japan. In total, 37,504 pregnant Japanese women and their partners were included in this birth cohort study. A multinomial logistic regression model was used to evaluate the associations of parental birth weights with small-for-gestational-age (SGA) or large-for-gestational-age (LGA) infants. Associations between parental birth weight and low birth weight (LBW) infants or macrosomia were also examined, and linear associations between parental birth weight and SGA or LGA were found. The adjusted odds ratios (aORs) for SGA infants per 500 g decrease in maternal and paternal birth weights were 1.50 (95% confidence interval [CI],1.43-1.58) and 1.31 (95% CI, 1.25-1.38), respectively. The aORs for LGA infants per 500 g increase in maternal and paternal birth weights were 1.53 (95% CI, 1.47-1.60) and 1.41 (95% CI, 1.35-1.47), respectively. The association between parental birth weight and LBW infants or macrosomia was also linear. The aORs for LBW infants per 500 g decrease in maternal and paternal birth weights were 1.47 (95% CI, 1.40-1.55) and 1.25 (95% CI, 1.19-1.31), respectively. The aORs for macrosomia per 500 g increase in maternal and paternal birth weights were 1.59 (95% CI, 1.41-1.79) and 1.40 (95% CI, 1.23-1.60), respectively. Parental birth weight was found to be associated with infant birth weight even after adjusting for various parental factors. Furthermore, maternal birth weight was more strongly associated with infant birth weight than with paternal birth weight.

Birth Weight Predicts Anthropometric and Body Composition Assessment Results in Adults: A Population-Based Cross-Sectional Study

BACKGROUND

A poor intrauterine environment is associated with increased risks of hypertension, chronic kidney disease, and/or diabetes. This study evaluated relationships between birth weight and body habitus in a representative sample of the general population.

METHODS

Adult participants were asked to complete a birth weight questionnaire. Associations between various current anthropometric and body composition measurements and birth weight were investigated.

RESULTS

Of 7,157 respondents, 4,502 reported their birth weight, which ranged from 0.4 to 7.0 kg with a mean and standard deviation of 3.37±0.7 kg; of these, 384 had low birth weights (LBWs; <2.5 kg). In females, lower birth weights were associated with lower height, weight, lean body mass (LBM), total body water (TBW), fat mass (FM), fat%, and fat-free mass (FFM) than those of higher older birth weights (quintiles); however, waist circumference (WC), and hip circumference (HC) were similar across quintiles. In males, LBW was similarly associated with lower height, weight, LBM, TBW, FM, fat%, and FFM, and also with lower WC and HC. The obesity markers such as WC, WHR, and body mass index (BMI) were 47%, 61%, and 45% greater, respectively, in LBW females compared to normal birth weight females, while these associations showed non-significant trend in males with LBW.

CONCLUSION

In adult male and female respondents, LBW was associated with lower body habitus: central obesity and body fatness (BMI, FM, fat%, FFM, FM/FFM, and FM/FFM²) were more pronounced in females than males, even after taking into account current physical activity and socioeconomic status. These findings indicate LBW may contribute to high blood pressure, dysglycemia and metabolic-abnormalities in adults.

Large for Gestational Age and Obesity-Related Comorbidities

Both small for gestational age and large for gestational age (LGA) size at birth are associated with metabolic complications throughout life. The long-term consequences of LGA have been investigated in only a few studies. LGA is thought to be associated with early obesity and metabolic risk. Understanding how LGA can influence later obesity risk is important for pediatric obesity interventions. Pregnant women who are overweight or obese are at high risk of having LGA babies. Infants born LGA are at increased risk of becoming overweight or obese children, adolescents, and young adults and can have an increased risk of metabolic syndrome later in life and giving birth to LGA offspring. Education and intervention for weight control before and during pregnancy should be conducted to prevent LGA births. Particular attention is needed for women of childbearing age who are diabetic and obese, which could be the starting point for lifelong management of obesity.

Infancy and Childhood Obesity Grade Predicts Weight Loss in Adulthood: The ONTIME Study

We examined the relationships between intergenerational obesity, weight and size at birth, and obesity from infancy to adolescence with weight loss in response to a dietary intervention. We studied 4264 participants (3369 women; mean age 41.5 ± 12.9 years) of the ONTIME study. Participants followed a weight-loss treatment based on a Mediterranean diet. Associations between grandparental and parental obesity grade, birth weight and size, and obesity grade in infancy, childhood and adolescence with total weight loss in response to treatment were assessed, using multivariate linear regression models. A lower weight loss (kg) in response to treatment was found among participants who were obese during infancy (beta coefficient -2.13 kg; 95% CI, -3.96, -0.30; p = 0.023). Furthermore, obesity during infancy and also during childhood was associated with a slower weekly rate of weight loss during treatment (p < 0.05). In conclusion, obesity in infancy and in childhood impairs the weight-loss response to dietary treatments in adulthood. Tackling obesity throughout early life may improve the effectiveness of weight-loss interventions in adulthood.

Maternal exposure to cold spells during pregnancy is associated with higher blood pressure and hypertension in offspring later in life

We aimed to investigate whether month of birth is associated with blood pressure (BP) and prevalent hypertension in adults from a region with frost-free days of <150 days and average temperatures - 13°C in winter, Xinjiang, China. We analyzed data for 6158 subjects from several surveys. We divided participants into April to August (n = 2624) and September to March (n = 3534) groups, based on length of maternal exposure to cold months, and analyzed BP, prevalent hypertension, and related factors. Diastolic BP in total subjects and systolic and diastolic BP in male subjects born between April and August were significantly higher than in those born between September and March. In sensitivity analysis, untreated males born between April and August showed significantly higher systolic and diastolic BP than did their counterparts. Subjects born between April and August showed significantly higher prevalence of hypertension (31.3% vs 27.8%, P = .003), and isolated systolic (23.3% vs 20.8%, P = .018) and diastolic hypertension (24.5% vs 21.4%, P = .004), than those born between September and March, which is similar for men. Birth between April and August showed 1.68 (95% CI: 1.06-2.67, P = .027)-fold increased odds for the prevalence of hypertension, independent of gender, age, body mass index, waist circumference, cigarette consumption, alcohol intake, and family history, compared with their counterparts. In conclusion, maternal exposure to cold spells during pregnancy may be associated with the increased risk of hypertension in offspring later in life, particularly among males, suggesting the involvement of maternal cold exposure during pregnancy in offspring hypertension development.

Associations between birth weight and glucose intolerance in adulthood among Greenlandic Inuit

AIMS

To examine the association between birth weight and glucose intolerance in adult Greenlandic Inuit.

METHODS

We examined 1429 participants aged 18-56 years from two population-based, cross-sectional studies in Greenland with information on birth weight. Oral glucose tolerance tests, anthropometric measures and ultrasound of abdominal tissue were performed. Associations of birth weight with glucose markers were analysed using linear or logistic regressions. Spline analyses were conducted to examine u-shaped associations. Adjustments were done for age, sex, birth place, family history of diabetes, genetic admixture, TBC1D4 p.Arg684Ter carrier status, BMI and visceral adipose tissue.

RESULTS

The median birthweight was 3300 g and 3.9% had type 2 diabetes, T2DM. Spline analyses indicated overall linear associations. In fully adjusted analyses, an increase in birth weight of 1 kg was associated with a change in fasting plasma glucose of -0.06 mmol/L (95%CI: -0.11, -0.01), 2-h plasma glucose of -0.16 mmol/L (95%CI: -0.35, 0.02), HOMA-IR of -5.45% (95%CI: -10.34, -0.29), insulin sensitivity index of 7.04% (95%CI: 1.88, 12.45) and a trend towards a reduced risk of hyperglycaemia and T2DM, although statistically insignificant.

CONCLUSIONS

Birth weight was inversely associated with hepatic and peripheral insulin resistance independently of adult adiposity. Thus, the findings support low birth weight as a contributing factor for glucose intolerance in adult Inuit in Greenland.

Developmental origins of health and disease: current knowledge and potential mechanisms

Epidemiologic and clinical research has provided a large body of evidence supporting the developmental origins of health and disease (DOHaD), but there has been a relative dearth of mechanistic studies in humans due to the complexity of working with large, longitudinal cohorts. Nonetheless, animal models of undernutrition have provided substantial evidence for the potential epigenetic, metabolic, and endocrine mechanisms behind DOHaD. Furthermore, recent research has explored the interaction between the environment and the gastrointestinal system by investigating how the gut microbial ecology may impact the capacity for nutrient processing and absorption in a manner that may limit growth. This review presents a summary of current research that supports the concept of DOHaD, as well as potential mechanisms and interactions that explain how nutrition in utero and during early childhood influences lifelong health.

Blood pressure and heart rate during stress in children born small for gestational age

BACKGROUND

Increased sympathetic nervous system activity has been proposed as a potential mechanism for the blood pressure (BP) elevation seen in individuals born small for gestational age (SGA). This study was carried out to detect the changes in BP and heart rate (HR) in children born SGA during exposure to stress and to assess for changes in urinary catecholamine excretion.

METHODS

Nineteen children aged 6-14 years born SGA and 17 age- and gender-matched healthy controls were included in the study. The stress test included a mathematical test and venipuncture. BP and HR were monitored during the test. Spot urine samples were collected at baseline and after the stress test to determine dopamine, epinephrine and norepinephrine levels.

RESULTS

At baseline, there was no difference in BP and HR between the SGA and control groups, but mean urinary norepinephrine levels were slightly higher in the SGA group (55.7 ± 16.1 vs. 43.4 ± 3.8 mcg/gCr; P = 0.10). Compared to the control group, mean maximal HR increase was higher in the SGA group (31.3 ± 3.1 vs. 19.2 ± 3.8%; P = 0.008), and mean duration of maximal HR to baseline HR was longer (186 ± 23 vs. 97 ± 13 s, respectively; P = 0.003). There was a significant negative correlation between birth weight and maximal HR increase (r = -0.497, P = 0.003).

CONCLUSION

Children born SGA showed significantly greater increases in HR and significantly longer periods of tachycardia during exposure to stress than did healthy controls. The rise in HR was inversely correlated with birth weight. These findings suggest that children born SGA have a greater increase in sympathetic response when exposed to stress than do healthy individuals.

Use of the Dietary Guideline Index to assess cardiometabolic risk in adolescents

The long-term adherence to the dietary guidelines has not been evaluated against emergence of cardiometabolic risks in adolescents with increasing rates of obesity. The present study aimed to (1) determine the level of adherence to the guidelines using the Australian Dietary Guideline Index for Children and Adolescents (DGI-CA) in adolescents of age 14 and 17 years and to (2) examine the relationship between their assessed diet quality and concurrently measured cardiometabolic risk factors over time. Data were analysed from the Western Australian Pregnancy Cohort (Raine) Study. The DGI-CA was determined from a FFQ. Anthropometry and fasting biochemical measures were taken using standard procedures. Hierarchical linear mixed models examined associations between cardiometabolic risk factors and DGI-CA, adjusting for socio-economic status, physical activity, BMI, and sex, and examining for interactions. The mean DGI-CA scores were 47·1 (sd 10·2) at 14 years (n 1419) and 47·7 (sd 11·0) at 17 years (n 843), and were not different between sex. There was a significant inverse association between DGI-CA and insulin, homeostasis model assessment score and heart rate. The DGI-CA was positively associated with BMI (P= 0·029) but negatively with waist:hip ratio (P= 0·026). It was not associated with lipids or blood pressure, with the exception of a negative association with TAG (P= 0·011). The degree of adherence in the Raine Study adolescents was suboptimal but similar to the Australian Children's Nutrition and Physical Activity Survey. The present study shows that, at any particular time, better diet quality was associated with better insulin sensitivity and TAG levels and decreased abdominal fatness.

Faster increase in body mass index between ages 8 and 13 is associated with risk factors for cardiovascular morbidity and mortality

BACKGROUND AND AIMS

Excess childhood weight is associated with cardiovascular disease (CVD) in adulthood. Whether this is mediated through adult body mass index (BMI) and associated risk factors such as metabolic derangements remains unclear. The aim was to examine whether childhood BMI velocity (Δkg m(-2) per year) was associated with adult CVD mortality and to examine how adult BMI and cardiometabolic risk factors contribute to the association.

METHODS AND RESULTS

Subjects were 1924 Icelanders born between 1921 and 1935 and living in Reykjavik when recruited into a longitudinal study from 1967 to 1991. From ages 8-13 years, BMI velocity was calculated to quantify the association between childhood growth and adult CVD mortality. Deaths from recruitment to 31 December 2009 were extracted from the national register. There were 202 CVD deaths among men and 90 CVD deaths among women (mean follow-up: 25.9 years). Faster BMI velocity from ages 8-13 years was associated with CVD mortality when comparing those in the highest versus lowest tertile with corresponding hazard ratio (HR) (95% confidence interval (CI)): 1.49 (1.03, 2.15) among men and 2.32 (1.32, 4.08) among women after adjustment for mid-life BMI and CVD risk factors. Faster childhood BMI velocity was associated with elevated CVD risk factors among men at mid-life but these associations were less pronounced among women.

CONCLUSION

Faster increase in BMI from ages 8-13 years was associated with an increased CVD mortality risk. Children with early growth spurts coupled with excess weight gain during this transition period from childhood into adolescence should be closely monitored to ensure better health in adulthood.

Size at birth and abdominal adiposity in adults: a systematic review and meta-analysis

We performed a systematic literature review on the associations between birth size and abdominal adiposity in adults, while also investigating the role of the adjustment for adult body mass index (BMI). MEDLINE, Scopus, Web of Science, LILACS and SciELO databases were searched for articles published up to February 2013. Only prospective studies were included. After screening 2,570 titles, we selected 31 publications for the narrative synthesis, of which 13 were considered to be of high methodological quality. Six main indicators of birth size were identified, and birth weight (BW) was the most extensively studied. Most studies relied on anthropometric measurements as proxies for abdominal fatness or as indicators of body fat distribution. Few studies assessed abdominal adiposity through imaging methods, generally with small sample sizes. Eleven articles could be included in the meta-analyses. BW was found to be positively associated with waist circumference in adulthood, but the association disappeared after adjustment for adult BMI. In contrast, there was no association between BW and waist-to-hip ratio, whereas a strong negative association became evident after controlling for adult BMI. In conclusion, BW seems to be associated with larger adult size in general, including both waist and hip circumferences. The marked change in coefficients after adjustment for adult BMI suggests that post-natal growth strongly affects relative central adiposity, whereas BW per se does not play a role. Given the potential impact of post-natal growth, further research is needed to identify different growth trajectories that lead to abdominal adiposity, as well as studies on interactions of foetal and post-natal growth patterns.

Early peak height velocity and cardiovascular disease mortality among Icelandic women

INTRODUCTION

Early pubertal onset among girls has been associated with cardiovascular disease (CVD) risk factors. We examined whether timing of peak height velocity (PHV), an early marker of maturity, was associated with CVD mortality.

MATERIALS AND METHODS

We analysed 973 Icelandic women, born 1921-1935, with annual childhood growth measures from ages 8-13 years, recruited into the longitudinal Reykjavik study 1968-1991. CVD deaths from recruitment to December 2009 were recorded.

RESULTS

Eighty-six women died from CVD, 42 deaths from coronary heart disease (CHD). Compared to girls with PHV after age 12, girls with PHV < 11 years and between 11 and 12 years had greater risk of CVD mortality, hazard ratio 1.87 (95% confidence interval 1.07-3.26, P = 0.028) and 2.56 (1.52-4.31, P < 0.001), respectively. Comparable associations were observed with CHD cases 2.27 (1.17-4.44, P = 0.016) as well as non-CHD CVD cases 2.21 (1.17-4.19, P = 0.015) when comparing girls with PHV after versus prior to age 12. Timing of PHV was not associated with traditional CVD risk factors in mid-life including body mass index and adverse lipid profiles or with all-cause mortality.

DISCUSSION

Earlier timing of PHV in girls may increase the lifetime risk of CVD mortality and may be an important determinant for later cardiovascular health.

Effect of birth year on birth weight and obesity in adulthood: comparison between subjects born prior to and during the great depression in Iceland

Background

Many epidemiological studies have linked small size at birth to adverse adult health outcomes but the relative influence of environmental exposures is less well established.

Methods

The authors investigated the impact of prenatal environmental exposure by comparing 2750 participants born before (1925–1929) and during (1930–1934) the Great Depression in Reykjavik, Iceland. Calendar year served as proxy for environmental effects. Anthropometric measurements at birth and school-age (8–13 years) were collected from national registries. Participants were medically examined as adults (33–65 years).

Results

Mean birth weight, adjusted for maternal age and parity, decreased by 97 g (95% confidence interval (CI): 39, 156) for men and 70 g (95% CI: 11, 129) for women from 1925 to 1934; growth at school-age was significantly reduced for participants growing during the Depression. As adults, women prenatally exposed to the Depression had higher body mass index (Δ0.6 kg/m², 95% CI: 0.2, 1.1), higher fasting blood glucose levels (Δ0.16 mmol/L, 95% CI: 0.07, 0.23) and greater odds of being obese 1.43 (95% CI: 1.01, 2.02) compared to unexposed counterparts. Non-significant associations were observed in men.

Conclusion

Reduction in birth weight due to rapid shifts in the economic environment appears to have a modest but significant association with later obesity for women while male offspring appear to be less affected by these conditions.

Birth size and adult size in same-sex siblings discordant for fetal growth in the Early Determinants of Adult Health study

Many studies have reported on relations between birth size and adult size but the findings to date are hard to compare due to the lack of uniform measures across studies. Interpretation of findings is also hampered by potential confounding by ethnic, socioeconomic and family factors. The purpose of this study is to explore these relationships in a comprehensive fashion, with multiple measures of birth size and adult size, using same-sex sibling controls discordant in birth weight to address potential confounding at the family level. Study subjects include pregnant women enrolled during 1959-1966 in the Child Health and Development Study in Oakland, CA and the Boston, MA, and providence, RI, sites of the Collaborative Perinatal Project in New England, currently combined into the New England Family Study. We assessed 392 offspring (mean age 43 years), the great majority as sibships as available. Our analyses confirm the positive association between birth weight and adult length reported in other studies, with a change in adult height of 1.25 cm (95% CI: 0.79 to 1.70 cm) for each quintile change in standardized birth weight. No associations were seen between birth weight and adult fatness for which findings in other studies are highly variable. As adult weight is likely to reflect recent variations in the adult nutritional environment rather than the early environment, it may be more useful for studies of birth size and adult size to focus on adult length rather than weight measures in evaluating the role of early influences on adult health.

The pioneer gut microbiota in human neonates vaginally born at term-a pilot study

The pioneer microbiota of the neonate may affect future actions of the immune system. This study aimed to map the pioneer microbiota in healthy neonates vaginally born at term. A subgroup of neonates born large for GA (LGA) was compared with the neonates appropriate for GA (AGA). Fecal samples were collected, within 48 h after birth, from 79 neonates. Quantitative PCR was used for enumeration of Lactobacillus, a subgroup of Lactobacillus common in the vagina, Bifidobacterium, Enterococcus, Enterobacteriaceae, and the Bacteroides fragilis group. Cloning and sequencing were applied for subgroups of neonates born LGA or AGA. Lactobacillus was detected in all neonates, whereas other bacterial groups were detected only in 14 to 30% of the subjects. The prevalence of Gram-negative Proteobacteria was higher in neonates born LGA, whereas Gram-positive Firmicutes was more prevalent in neonates born AGA (p < 0.001). This study contributed to increased knowledge of the pioneer microbiota and indicates that neonates born LGA had significantly different microbiota compared with those born AGA. As the early microbiota can be important for maturation of the immune system, the outcome from this study may be relevant in the care of pregnant woman and newborns.

Evidence for the intra-uterine programming of adiposity in later life

AIM

Research in animals has shown that altering foetal nutrition by under-nourishing or over-nourishing the mother or rendering her diabetic or foetal exposure to glucocorticoids and toxins can programme obesity in later life. The increased adiposity is mediated by permanent changes in appetite, food choices, physical activity and energy metabolism. In humans, increased adiposity has been shown in people who experienced foetal under-nutrition due to maternal famine or over-nutrition due to maternal diabetes. Lower birth weight (a proxy for foetal under-nutrition) is associated with a reduced adult lean mass and increased intra-abdominal fat. Higher birth-weight caused by maternal diabetes is associated with increased total fat mass and obesity in later life. There is growing evidence that maternal obesity, without diabetes, is also a risk factor for obesity in the child, due to foetal over-nutrition effects. Maternal smoking is associated with an increased risk of obesity in the children, although a causal link has not been proven. Other foetal exposures associated with increased adiposity in animals include glucocorticoids and endocrine disruptors.

CONCLUSIONS

Reversing the current obesity epidemic will require greater attention to, and better understanding of, these inter-generational (mother-offspring) factors that programme body composition during early development.

Infant weight gain, duration of exclusive breast-feeding and childhood BMI – two similar follow-up cohorts

Objective

To describe the association between duration of exclusive breast-feeding (EBF), weight gain in infancy and childhood BMI in two populations with a long duration of EBF.

Design

Cohort study with follow-up in childhood. Breast-feeding status was reported monthly during infancy. Weight and length were measured at birth, 2, 6 and 12 months of age, as well as in childhood at 6 or 10 years of age.

Setting

Iceland and Denmark.

Subjects

Randomly selected healthy newborns from Denmark (n 85) and Iceland (n 100).

Results

Infants exclusively breast-fed for ≤2 months gained 348 (95% CI 69, 626) g more weight from 2 to 6 months than infants exclusively breast-fed for 3–4 months (P = 0·009). Weight gain from 6 to 12 months was found to be greater among infants exclusively breast-fed for ≤2 months compared with those exclusively breast-fed for ≥5 months (P = 0·008). A greater weight change, in terms of Z-score, between the ages of 2 and 6 months was associated with higher Z-score of childhood BMI, adjusted for birth weight, country and duration of EBF (B = 0·49, se = 0·11, P < 0·001, adj. R2 = 0·15). However, the association was much stronger in the Icelandic cohort than the Danish one.

Conclusions

Although duration of EBF was not associated with childhood BMI in the present study it may modulate growth rate in infancy, which is related to childhood BMI. However, other factors determinative for infant growth also need to be considered when assessing the relationship of early growth and nutrition to childhood overweight, as traditions in complementary food might differ between populations.

Effect of birth weight and postnatal weight gain on body composition in early infancy: The Generation R Study

BACKGROUND

Rapid postnatal weight gain is associated with obesity and type 2 diabetes in later life. The influence of rapid weight gain on body composition in early infancy is still unknown and the critical periods of weight gain for later disease are debated.

AIMS

To investigate the effect of birth weight and rapid weight gain on body composition in the first 6 months of life.

STUDY DESIGN

The Generation R Study, a population-based prospective cohort study from fetal life onwards.

SUBJECTS AND OUTCOME MEASURES

We measured body fat and fat distribution by skinfold thickness at the age of 6 weeks and 6 months in 909 Dutch term infants. Analyses were adjusted for current body mass index, sex and maternal socioeconomic status, pre-pregnancy body mass index, height and duration of breastfeeding.

RESULTS

Upward postnatal weight percentile change was associated with increased skinfold thickness, percentage body fat at 6 weeks and 6 months and a larger truncal/peripheral fat ratio at 6 months (p<0.01 for all). Birth weight was inversely associated with truncal/peripheral fat ratio (p<0.01) but not with relative body fat at 6 months.

CONCLUSION

During early postnatal rapid weight gain infants do not grow in all body tissues in equal measure. Instead, they acquire relatively large amounts of fat, which is preferentially distributed to the truncal region. Long term observational studies have to assess if such changes in body composition persist into adulthood.

Anthropometric characteristics as predictors of coronary heart disease in women

OBJECTIVES

Obesity and other anthropometric measures are clearly related to risk of coronary heart disease (CHD), although debate remains as to which measures are most important and how the impact of obesity varies over the life course.

AIM

We aimed to investigate these issues in a large cohort of Swedish women. The Women's Lifestyle and Health Cohort Study includes 49 259 women, aged 30-50 years at baseline (1991-1992) when an extensive questionnaire was completed.

METHODS

Women were given standard instructions for self-measurement of anthropometric characteristics. Women were followed through linkages to national registries until December 2003, during which time 256 cases of incident fatal CHD or nonfatal myocardial infarction occurred.

RESULTS

Waist circumference was associated with increased CHD risk after multivariate adjustment for confounders (HR = 1.9; 95% CI:1.1-3.3; highest versus lowest quartile), whereas height, weight and hip circumference were not. Measures of obesity were strongly related to CHD, and after mutual adjustment, waist-hip ratio (HR = 1.9, 95% CI: 1.2-3.2) was more closely related to CHD risk than BMI (HR = 1.5, 95% CI: 1.0-2.4). Risk of CHD was increased in women who remained heavy, those who were heavy at age 18, and those with low birth weight.

CONCLUSIONS

In conclusion, there is strong evidence for supporting control of obesity, in particular avoidance of abdominal obesity, as a strategy to prevent CHD.

Small birth weight and later body composition and fat distribution in adolescents: the Avena study

OBJECTIVE

To assess the association between birth weight and body composition and fat distribution in adolescents, and to test the possible sex-specific effect in these relationships.

METHODS AND PROCEDURES

A total of 1,223 adolescents 13-18.5 years old (553 male adolescents and 670 female adolescents) born at >35 weeks, were selected from a cross-sectional multicenter study conducted in five Spanish cities in 2000-2002. BMI was calculated from weight and height. Triceps and subscapular skinfold thickness (ST) were measured on the left side, and fat mass (FM) and fat-free mass (FFM) were estimated according to the equations of Slaughter et al. Subscapular skinfold adjusted by tricipital (ST) and waist circumference were used as markers of central adiposity.

RESULTS

Birth weight Z-score was positively associated with FFM in female adolescents (P<0.001), but not in male adolescents, after controlling for age, pubertal stage, gestational age, socioeconomic status, physical activity, and current height (P<0.001 for interaction between adjusted birth weight Z-score and sex). Adjusted birth weight Z-score was inversely associated with central adiposity in male and female adolescents as measured by ST (P=0.026).

DISCUSSION

These results provide further evidence that gender has an important influence on the programming effect of birth weight on later FFM in adolescents because the effect was only observed in female adolescents. Our results suggest that small size for gestational age at birth could program more central subcutaneous fat deposition in adolescents of both sexes, but further research is needed on this issue.

What evidence is there that adjustment for adult height influences the relationship between birth weight and blood pressure?

BACKGROUND

The inverse association between birth weight and blood pressure may partly be the result of inappropriate adjustment for adult body size, but it remains unclear whether adjustment for adult height elicits this effect.

AIM

The study investigated the impact of adjustment for adult height on the relationship between birth weight and blood pressure.

METHODS

A systematic search of Medline from 1996 to 2006 was conducted using the terms 'birth weight', 'blood pressure' and 'hypertension', and any papers containing linear regression analyses of blood pressure on birth weight for populations with an average age of 25+ were eligible for inclusion in comparative meta-analyses.

RESULTS

None of the 30 studies identified had published regression coefficients for blood pressure on birth weight before and after adjustment for adult height, and only two studies were found to adjust for adult height at all. Data from these studies were obtained, and it was found that adjustment for height made the association between birth weight and systolic blood pressure (SBP) more negative in one study but less negative in the other. When compared with meta-analyses of comparable models, it was found that both studies were substantially different from the combined estimate of the relationship between birth weight and SBP.

CONCLUSIONS

Both the differences between the two selected studies and their differences from the combined estimates obtained by meta-analysis are likely to be due to differences in the age of the participants. The relationship between birth weight and SBP tended to become more strongly inverse in studies with older participants. Additionally, the correlations between height and SBP were found to change from positive to negative with increasing age, which explained the differential impact of adjustment for height in the two selected studies. It therefore appears that adjustment for height may have little effect for older participants, but more so for younger participants.

Programming of body composition by early growth and nutrition

There is now compelling evidence that growth patterns in early life are associated with risk of the metabolic syndrome in adulthood, although the relative importance of prenatal v. postnatal growth for such associations remains controversial. Body composition may play a key role in the ‘programming’ of such diseases, through itself being programmed by early growth, and perhaps also by being a mediator of the programming process. Early studies reporting positive associations between birth weight and adult BMI suggested a tendency for large babies to become obese adults. Such findings appeared contradictory to the many studies linking low birth weight with increased risk of the metabolic syndrome. Recent studies now indicate that birth weight is strongly predictive of later lean mass, and has a much weaker association with later fatness. Studies that link low birth weight with a more central adipose distribution in later life remain controversial, and require confirmation using more sophisticated methodologies. Findings for infant growth rate appear population-specific, with infant weight gain predicting subsequent lean mass in developing countries, but predicting subsequent fat mass and obesity in industrialised populations. Further studies are required on this issue, to ensure that appropriate public health policies are recommended for countries across the range of economic development. Although the links between early growth and later disease risk implicate early-life nutrition, either in utero or during infancy, few prospective studies have explored the influence of early diet on later body composition. Many studies have associated breast-feeding with a reduced prevalence of obesity categorised by BMI; however, the few studies directly evaluating childhood fatness provide little support for this hypothesis. Recent advances in the ability to measure body composition during the infant period offer a major opportunity to improve the understanding of the nutritional programming of body composition and its contribution, or lack thereof, to subsequent disease risk.

Tracking of overweight from early childhood to adolescence in cohorts born 1988 and 1994: overweight in a high birth weight population

OBJECTIVE

To investigate the prevalence and tracking of overweight and obesity in childhood cohorts born 1988 and 1994 in a population of high birth weight.

SUBJECTS

Icelandic cohorts born in 1988 and 1994.

MATERIALS AND METHODS

Out of 1328, 9- and 15-year-old children from 18 randomly selected schools all over Iceland, 934 participated (71%). Height and mass were measured by the investigators. Also, height and mass at birth, and at age 2.5, 6, 9, and 12 years, were collected from maternity wards and school health registers.

RESULTS

The prevalence of overweight children ranged from 10.1% for 2.5-year-olds to 18.7% for 9-year-olds. No difference was observed between the two cohorts or sex. The prevalence of obesity in the 1994 cohort (4.3%) was significantly higher (P = 0.01) at age 6 years, compared to the 1988 cohort (1.1%). The children who were overweight at age 2.5 years were more likely to be overweight at age 6 (OR=12.2) and 9 years (OR=4.9), but not significantly at age 12 or 15 years, compared with normal weight 2.5-year-olds. Overweight children at age 6 or 9 years were much more likely (OR 10.4 and OR 18.6, respectively) to be overweight at age 15 years compared to their normal weight peers. Of overweight 6-year-olds, 51% were overweight at 15 years, and were about one-third of all overweight children at that age. The children that weighed above the 85th percentile at birth were more likely than the other children to be overweight at the age of 6 years (OR = 1.8), 9 years (OR = 2.1), and 15 (OR = 2.0) years.

CONCLUSION

The results show high prevalence of overweight and obesity even before the start of compulsory schooling. Approximately, 51% of overweight 6-year-olds were still overweight after puberty. Therefore, preschool overweight prevention, along with prevention at school age, seems to be of uttermost importance.

Early programming of body composition and fat distribution in adolescents

Size at birth and early postnatal growth are determinants of adult height and BMI. The aim of this study was to evaluate the effect of birth weight on body composition and fat distribution in a group of Spanish adolescents. Current body composition was assessed by both skinfold thickness and dual X-ray absorptiometry in 234 adolescents born at term (140 girls and 94 boys), now aged 13-18 y and living in the city of Zaragoza. Relative fat distribution was estimated using the ratio of the subscapular to triceps skinfolds (S:T). Birth weight and gestational age were assessed by a questionnaire. Birth weight was inversely associated with the S:T ratio (P < 0.05) in boys and directly associated with bone mass (P < 0.01) and fat-free mass (P < 0.05) in girls. This association was independent of factors such as age, Tanner stage, gestational age, socioeconomic status, physical activity, and height. In conclusion, our data support the hypothesis that impaired fetal growth, measured by birth weight, may be related to central fat distribution in boys and decreased bone and fat-free mass in girls.