Infant feeding and components of the metabolic syndrome: findings from the European Youth Heart Study

Effect and Concern of Breastfeeding in Infants

Human breast milk is considered the optimal source of nutrition for infants and is recommended as the exclusive nutrient source for term infants during the first six months of life. Existing evidence strongly supports the direct benefits of breastfeeding, encompassing benefits for nutrition, gastrointestinal function, and protection against acute illness in both term and preterm infants. Previously, we demonstrated a notable reduction in a urinary marker of oxidative DNA damage in breastfed term and preterm infants compared to formula-fed infants. While long-term benefits of breastfeeding on neurodevelopmental outcomes and adult health have been reported, the effects may be relatively modest and limited.

Factors affecting exclusive breastfeeding in the first month of life among Amazonian children

Early life feeding practices can directly affect the growth, development, and survival of a child. This study aimed to estimate the frequency of and factors associated with exclusive breastfeeding (EBF) in the first month of life among Amazonian infants. We used data of 1,523 mother-child pairs of the MINA-Brazil birth cohort study. Mothers were interviewed soon after delivery at baseline and by telephone at 30-45 days postpartum (n = 962, 63.2% of those eligible). Kaplan-Meier survival analysis and accelerated failure-time (AFT) models were used to estimate the probability of EBF and the factors associated with EBF duration in the first month. At 30 days of age, 36.7% of the studied population (95% confidence interval [CI] 33.6-39.8) were exclusively breastfed, with a median duration of 16 days. Considering all eligible children for follow-up, the probability of EBF in the first month was 43.7% (95% CI 40.4-46.8), and the median duration was 30 days. The duration of EBF (time-ratio, TR) was 28% longer among multiparous mothers (TR 1.28; 95% CI 1.11-1.48). The use of a pacifier and the occurrence of wheezing were associated with a reduced EBF duration by 33% (TR 0.67; 95% CI 0.58-0.77) and 19% (TR 0.80; 95% CI 0.70-0.93), respectively. These results highlight that EBF among children in the Brazilian Amazon is considerably below international recommendations, and indicate the immediate need to plan and implement actions to promote and support breastfeeding early in life.

Metabolic Syndrome and Its Associated Early-Life Factors among Chinese and Spanish Adolescents: A Pilot Study

Metabolic syndrome (MetS) is a growing problem worldwide in adolescents. This study compared two sample populations of young people in Spain and China, and analyzed the association of birth weight and breastfeeding duration with MetS. A cross-sectional study was conducted in adolescents (10–15 years old); 1150 Chinese and 976 Spanish adolescents. The variables analyzed were anthropometric characteristics, biochemical markers, and demographic characteristics using the same methodology and data collection protocol. Also, birth weight and breastfeeding were retrospectively analyzed during the first year of life. The results showed statistically significant differences between the two groups in reference to body mass index (BMI), blood pressure, triglyceride, glucose, and high-density lipoprotein cholesterol (HDL-C) levels. The MetS prevalence was higher in Spanish adolescents (2.5%) than in the Chinese group (0.5%). Breastfeeding duration was inversely associated with hypertriglyceridemia, low HDL-C, and MetS, whereas higher birth weight was associated with hyperglycemia, low HDL-C, hypertriglyceridemia, and abdominal obesity. Spanish adolescents showed more altered MetS components, and consequently, a higher MetS prevalence than the Chinese adolescents. This made them more vulnerable to cardiometabolic risk. Our results highlight the need for interventions designed by health professionals, which would encourage pregnant women to breastfeed their children.

Effect of human breast milk on biological metabolism in infants

The metabolic changes that occur during the postnatal weaning period appear to be particularly important for future health, and human breast milk is considered to provide the optimal source of nutrition for infants. Our previous studies examined the effect of feeding type on antioxidative properties, glucose and insulin metabolism, the lipid profile, metabolomics, and prostaglandin (PG) metabolism in term and preterm infants. A urinary marker of oxidative DNA damage (8-hydroxy-2'-deoxyguanosine) was significantly lower in breast-fed term and preterm infants than in formula-fed infants. Markers of insulin sensitivity were significantly lower and atherosclerotic indices were significantly higher in breast-fed preterm infants than in mixed-fed infants at discharge. On urinary metabolomics analysis, choline, choline metabolites, and lactic acid were significantly lower in breast-fed term infants than in formula-fed infants. Urinary PGD₂ metabolite level in breast-fed term infants was also significantly lower than in formula-fed term infants. This indicates that human breast milk affects biological metabolism in early infancy.

The association of breastfeeding with insulin resistance at 17 years: Prospective observations from Hong Kong's "Children of 1997" birth cohort

Breastfeeding has many benefits for mother and infant. Whether breastfeeding also protects against type 2 diabetes is unclear. To clarify the role of breastfeeding in type 2 diabetes, we assessed the association of breastfeeding with insulin resistance in late adolescence in a birth cohort from a non-Western setting where breastfeeding was not associated with higher socio-economic position. We used multivariable linear regression, with multiple imputation and inverse probability weighting, to examine the adjusted associations of contemporaneously reported feeding in the first 3 months of life (exclusively breastfed, mixed feeding, or always formula-fed) with fasting glucose, fasting insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) at 17 years in a subset (n = 710, 8.6% of entire cohort) of the Hong Kong Chinese birth cohort "Children of 1997." We found a graded association of breastfeeding exclusivity in the first 3 months of life with lower fasting insulin and HOMA-IR (p-for-trend < .05), but not fasting glucose, at 17 years. Exclusively breastfed adolescents (7%) had nonsignificantly lowest fasting insulin and HOMA-IR, adjusted for sex, birth weight, parity, length of gestation, pregnancy characteristics, parents' education, and mother's place of birth. Exclusively breastfeeding for 3 months may be causally associated with lower insulin resistance in late adolescence. Further follow-up studies into adulthood are required to clarify the long-term protection of breastfeeding from type 2 diabetes.

Effects of Promoting Long-term, Exclusive Breastfeeding on Adolescent Adiposity, Blood Pressure, and Growth Trajectories: A Secondary Analysis of a Randomized Clinical Trial

IMPORTANCE

Evidence that breastfeeding reduces child obesity risk and lowers blood pressure (BP) is based on potentially confounded observational studies.

OBJECTIVE

To investigate the effects of a breastfeeding promotion intervention on adiposity and BP at age 16 years and on longitudinal growth trajectories from birth.

DESIGN, SETTING, AND PARTICIPANTS

Cluster-randomized Promotion of Breastfeeding Intervention Trial. Belarusian maternity hospitals and affiliated polyclinics (the clusters) were allocated into intervention (n = 16) or control arms (n = 15) in 1996 and 1997. The trial participants were 17 046 breastfeeding mother-infant pairs; of these, 13 557 children (79.5%) were followed up at 16 years of age between September 2012 and July 2015.

INTERVENTIONS

Breastfeeding promotion, modeled on the Baby-Friendly Hospital Initiative.

MAIN OUTCOMES AND MEASURES

Body mass index (BMI, calculated as weight in kilograms divided by height in meters squared); fat and fat-free mass indices and percentage of body fat from bioimpedance; waist circumference; overweight and obesity; height; BP; and longitudinal growth trajectories. The primary analysis was modified intention-to-treat (without imputation for losses to follow-up) accounting for within-clinic clustering.

RESULTS

We examined 13 557 children at a median age of 16.2 years (48.5% were girls). The intervention substantially increased breastfeeding duration and exclusivity compared with the control arm (exclusively breastfed: 45% vs 6% at 3 months, respectively). Mean differences at 16 years between intervention and control groups were 0.21 (95% CI, 0.06-0.36) for BMI; 0.21 kg/m2 (95% CI, -0.03 to 0.44) for fat mass index; 0.00 kg/m2 (95% CI, -0.21 to 0.22) for fat-free mass index; 0.71% (95% CI, -0.32 to 1.74) for percentage body fat; -0.73 cm (-2.48 to 1.02) for waist circumference; 0.05 cm (95% CI, -0.85 to 0.94) for height; -0.54 mm Hg (95% CI, -2.40 to 1.31) for systolic BP; and 0.71 mm Hg (95% CI, -0.68 to 2.10) for diastolic BP. The odds ratio for overweight/obesity (BMI ≥85th percentile vs <85th percentile) was 1.14 (95% CI, 1.02-1.28) and the odds ratio for obesity (BMI ≥95th percentile vs <95th percentile) was 1.09 (95% CI, 0.92-1.29). The intervention resulted in a more rapid rate of gain in postinfancy height (1 to 2.8 years), weight (2.8 to 14.5 years), and BMI (2.8 to 8.5 years) compared with the control arm. The intervention had little effect on BMI z score changes after 8.5 years.

CONCLUSIONS AND RELEVANCE

A randomized intervention that increased the duration and exclusivity of breastfeeding was not associated with lowered adolescent obesity risk or BP. On the contrary, the prevalence of overweight/obesity was higher in the intervention arm. All mothers initiated breastfeeding, so findings may not apply to comparisons of the effects of breastfeeding vs formula feeding.

TRIAL REGISTRATION

isrctn.org: ISRCTN37687716; and clinicaltrials.gov: NCT01561612.

Influence of breastfeeding in the first months of life on blood pressure levels of preschool children

OBJECTIVE

To investigate whether breastfeeding in early life affects blood pressure of preschoolers.

METHODS

Cross-sectional study nested in a cohort from a municipality in the state of Minas Gerais, Brazil. All children in the cohort were invited for this study. Thus, between 2009 and 2010, blood pressure of 230 preschool children and their mothers, in addition to anthropometric variables, previous history, and socioeconomic status were evaluated. Blood pressure measurement was assessed in the morning, using automatic Omron^® HEM-714INT and HEM-781INT devices to measure the blood pressure of preschool children and their mothers, respectively. Logistic regression was used to study the association between breastfeeding and blood pressure. The significance level was set at 5%.

RESULTS

This study identified 19 (8.26%) preschool children with high blood pressure (values above the 90th percentile). High systolic blood pressure was associated with low birth weight (OR=5.41; 95% CI=1.45-20.23) and total breastfeeding duration of less than six months (OR=4.14; 95% CI=1.40-11.95). High diastolic blood pressure was not associated with any variable, whereas high systolic blood pressure/diastolic blood pressure ratio was associated with breastfeeding duration of less than six months (OR=3.48; 95% CI=1.34-9.1).

CONCLUSION

The results of this study indicate that preschoolers breastfed for a period of less than six months were more likely to have high blood pressure when compared to those breastfed for a longer period, suggesting a protective effect of breastfeeding against high blood pressure in this population.

Does lactation protect mothers against metabolic syndrome? Findings from the Tehran Lipid and Glucose Study

AIM

We aimed to explore the effect of lactation on development of metabolic syndrome in a prospective population-based study.

METHODS

From among 4028 female participants of the Tehran Lipid and Glucose Study, aged 15–50 years, without metabolic syndrome at the initiation of the study, 925 women were randomly selected to fill out the lactation questionnaire. Women were assigned to five groups based on lactation duration including: none, 1–6 months, 7–12 months, 13–23 months and 24 months or more. Over a 9-year follow-up, metabolic syndrome was compared between these groups, before and after adjustment for possible confounding variables.

RESULTS

Metabolic syndrome was developed in 12.1% of non-lactating women; it was 28.6%, 34.0%, 26.2% and 26.7% in women with 1–6, 7–12, 13–23 and 24 months or more of lifetime duration of lactation, respectively (P < 0.002). Adjustment for confounders revealed that women with 1–6 and 7–12 months of duration of lactation had significantly higher odds of metabolic syndrome in comparison to 24 months or more (1.4 and 1.3 times, respectively).

CONCLUSION

It seems that the longer duration of lactation up to 12 months may protect women against metabolic syndrome, in a dose–response manner.

Effects of breastfeeding on the risk factors for metabolic syndrome in preterm infants

Evidence suggests that breastfeeding during infancy lowers the risk of metabolic syndrome (MS) and its attendant risk factors in adult life. To investigate the influence of feeding type on the risk factors of MS, we assessed insulin sensitivity and lipid and apolipoprotein metabolism in preterm infants. Blood samples were collected from preterm infants at the time of discharge. Infants were separated into two groups: a breast milk (BM) group receiving ⩾90% of their intake from BM, and a mixed-fed (MF) group receiving ⩾50% of their intake from formula. The following indices were then compared between the two groups. Blood glucose and serum insulin levels were used to calculate the quantitative insulin sensitivity check index (QUICKI). We also measured serum total cholesterol (TC), low-density lipoprotein cholesterol (LDLc), high-density lipoprotein cholesterol (HDLc), apolipoprotein-A1 (apoA1) and apolipoprotein-B (apoB) levels, and the ratios of TC/HDLc, LDLc/HDLc and apoB/apoA1. The mean gestational age was 32.9 weeks at birth, and blood samples were collected at a mean corrected age of 37.4 weeks. There were 22 infants in the BM group and 19 in the MF group. QUICKI was significantly higher in the BM group. TC, HDLc and apoA1 were not significantly different between the groups, but LDLc and apoB levels were significantly higher in the BM group. The TC/HDLc, LDLc/HDLc and apoB/apoA1 ratios were significantly higher in the BM group. In preterm infants, the type of feeding exposure in the early postnatal period may influence glucose, lipid and apolipoprotein metabolism, and affect markers of MS.

Air pollution associated hypertension and increased blood pressure may be reduced by breastfeeding in Chinese children: the Seven Northeastern Cities Chinese Children's Study

BACKGROUND

Little is known about the association between air pollution and hypertension among children, and no studies report whether breastfeeding modifies this association in children.

METHODS

Nine thousand three hundred fifty-four Chinese children, ages 5-17 years old, from 24 elementary schools and 24 middle schools in the Seven Northeastern Cities during 2012-2013 were evaluated. The weight, height, and BP were measured. Four-year average concentrations of particles with an aerodynamic diameter of ≤10 μm (PM10), sulfur dioxide (SO2), nitrogen dioxides (NO2), ozone (O3), and carbon monoxide (CO) were calculated from monitoring stations. Two-level regression analysis was used to examine the effects, controlling for covariates.

RESULTS

The results showed that associations existed between hypertension and pollutants. The odds ratios for hypertension ranged from 1.12 per 46.3 μg/m3 increase for O3 (95% confidence interval [CI], 1.10-1.13) to 1.68 per 30.6 μg/m3 increase for PM10 (95% CI, 1.53-1.86). The increases in mean diastolic BP ranged from 0.58 mm Hg per 46.3 μg/m3 increase for O3 (95% CI, 0.52-0.63 mm Hg) to 2.89 mm Hg per 563.4 μg/m3 increase for CO (95% CI: 2.53-3.24 mm Hg). The increase in systolic BP ranged from 0.50 mm Hg per 46.3 μg/m3 increase for O3 (95% CI: 0.43-0.57 mm Hg) to 2.10 mm Hg per 30.6 μg/m3 increase for PM10 (95% CI, 1.73-2.47 mm Hg). Compared with children who had been breastfed, non-breastfed children exhibited consistently stronger effects.

CONCLUSION

Study findings indicate that high levels of PM10, SO2, NO2, O3, and CO are associated with increased arterial BP and hypertension among the children. Breastfeeding may reduce the risk.

Is breastfeeding protective for blood pressure in schoolchildren? A cohort study in northeast Brazil

OBJECTIVE

This study assessed the influence of breastfeeding and nutritional status of full-term infants on blood pressure at school age.

SUBJECTS AND METHODS

This was a cross-sectional study nested in a cohort of 375 infants recruited at birth between 1993 and 1994 in the state of Pernambuco, Brazil. A sample of 213 8-year-old children had their blood pressure measured. A multivariate linear regression analysis was used to identify the influence of low birth weight and breastfeeding duration on blood pressure, adjusting for socioeconomic conditions, maternal nutritional status, eating habits, growth rate (0-6 months), and the children's anthropometry at 8 years.

RESULTS

Mean values of children's blood pressure were significantly higher with lower duration of breastfeeding. Higher per capita family income, maternal body mass index and height, child's weight and length at birth, and child anthropometric dimensions at 8 years of age were associated with higher levels of blood pressure. The multivariate linear regression analysis showed that children who were breastfed for less than 40 days had higher systolic blood pressures, explaining 2.2% of its variation. Anthropometry at 8 years of age explained the higher variance in systolic blood pressure (12.6%) with emphasis on waist circumference (9.5%), followed by per capita income (3.2%) and maternal height (2.1%). Birth weight and length had no influence on blood pressure levels in this age group.

CONCLUSIONS

Children's waist circumference, duration of breastfeeding, socioeconomic conditions, and maternal nutritional status influenced blood pressure levels of schoolchildren born full term, rather than low birth weight.

Does breastfeeding influence the risk of developing diabetes mellitus in children? A review of current evidence

OBJECTIVE

The aim of this study was to perform a review to investigate the influence of breastfeeding as a protective agent against the onset of diabetes in children.

SOURCES

non-systematic review of SciELO, LILACS, MEDLINE, Scopus, and VHL databases, and selection of the 52 most relevant studies. A total of 21 articles, specifically on the topic, were analyzed (nine related to type 1 diabetes and 12 to type 2 diabetes).

DATA SYNTHESIS

The duration and exclusivity of breastfeeding, as well as the early use of cow's milk, have been shown to be important risk factors for developing diabetes. It is believed that human milk contains substances that promote the maturation of the immune system, which protect against the onset of type 1 diabetes. Moreover, human milk has bioactive substances that promote satiety and energy balance, preventing excess weight gain during childhood, thus protecting against the development of type 2 diabetes. Although the above mentioned benefits have not been observed by some researchers, inaccuracies on dietary habit reports during childhood and the presence of interfering factors have been considered responsible for the lack of identification of beneficial effects.

CONCLUSION

Given the scientific evidence indicated in most published studies, it is believed that the lack of breastfeeding can be a modifiable risk factor for both type 1 and type 2 diabetes. Strategies aiming at the promotion and support of breastfeeding should be used by trained healthcare professionals in order to prevent the onset of diabetes.

Breastfeeding and its prospective association with components of the GH-IGF-Axis, insulin resistance and body adiposity measures in young adulthood--insights from linear and quantile regression analysis

BACKGROUND

Breastfeeding may lower chronic disease risk by long-term effects on hormonal status and adiposity, but the relations remain uncertain.

OBJECTIVE

To prospectively investigate the association of breastfeeding with the growth hormone- (GH) insulin-like growth factor- (IGF) axis, insulin sensitivity, body composition and body fat distribution in younger adulthood (18-37 years).

DESIGN

Data from 233 (54% female) participants of a German cohort, the Dortmund Nutritional and Anthropometric Longitudinally Designed (DONALD) Study, with prospective data on infant feeding were analyzed. Multivariable linear as well as quantile regression were performed with full breastfeeding (not: ≤ 2, short: 3-17, long: >17 weeks) as exposure and adult IGF-I, IGF binding proteins (IGFBP) -1, -2, -3, homeostasis model assessment of insulin resistance (HOMA-IR), fat mass index, fat-free mass index, and waist circumference as outcomes.

RESULTS

After adjustment for early life and socio-economic factors, women who had been breastfed longer displayed higher adult IGFBP-2 (p(trend) = 0.02) and lower values of HOMA-IR (p(trend) = 0.004). Furthermore, in women breastfeeding duration was associated with a lower mean fat mass index (p(trend) = 0.01), fat-free mass index (p(trend) = 0.02) and waist circumference (p(trend) = 0.004) in young adulthood. However, there was no relation to IGF-I, IGFBP-1 and IGFBP-3 (all p(trend) > 0.05). Associations for IGFBP-2 and fat mass index were more pronounced at higher, for waist circumference at very low or high percentiles of the distribution. In men, there was no consistent relation of breastfeeding with any outcome.

CONCLUSIONS

Our data suggest that breastfeeding may have long-term, favorable effects on extremes of adiposity and insulin metabolism in women, but not in men. In both sexes, breastfeeding does not seem to induce programming of the GH-IGF-axis.

Breast-fed infants and their later cardiovascular health: a prospective study from birth to age 32 years

The aim of the present study was to evaluate the impact of infant breast-feeding on cardiovascular risk in young adults. This unique study group involved 158 subjects (eighty-two females) originally collected prospectively at birth in 1975 and followed up to the age of 32 years. Frequent visits during the first year guaranteed the knowledge of the precise duration of breast-feeding. All infants received at least some breast milk. Participants were assessed for both individual cardiovascular risk factors (blood pressure, plasma lipids, homeostatic model assessment of insulin resistance and waist circumference) and the general clinical risk of cardiovascular events by calculating the Framingham risk score (FRS) and the metabolic syndrome criteria score (NCEP-ATPIII; National Cholesterol Education Program's Adult Treatment Panel III). Data on lifestyle factors were carefully collected. Linear regression analyses revealed that the effect of the duration of breast-feeding was not relevant (0·02 decrease in the FRS per one additional breast-feeding month; 95 % CI - 0·19, 0·09). Similarly, the effect of breast-feeding was minor on all of the individual cardiovascular risk factors. We used sex, physical activity, dietary fat and vitamin C, smoking and alcohol consumption as covariates. Again, logistic regression analyses detected no significant impact of the duration of breast-feeding on the risk of the metabolic syndrome according to the NCEP-ATPIII (OR 0·95, 95 % CI 0·8, 1·1). The strongest independent predictor for later CVD risk was male sex. In conclusion, in this prospectively followed cohort of young adults born at term and at weight appropriate for gestational age, the duration of breast-feeding did not have an impact on the accumulation of cardiovascular risk factors.

Determinants of metabolic syndrome in Chinese schoolchildren

The objective of this study was to identify the potential risk factors of metabolic syndrome (MetS) among Chinese schoolchildren. A cross-sectional study among 624 children (357 boys and 267 girls, aged 9.6 ± 0.7 years) was conducted in Wuhan, China, from May to June 2010. MetS was defined according to the criteria proposed by De Ferranti and the International Diabetes Federation (IDF) criteria. Data on cardiorespiratory fitness (CRF), household income, parental hypertension, and children's personal information, including birth weight, preterm birth, and breast-feeding, reported by their parents were obtained. Multiple logistic regression showed that CRF (odds ratio [OR] = 0.68; 95% confidence interval [CI] = 0.60-0.77), breast-feeding (OR = 0.32; 95% CI = 0.10-0.97), and paternal hypertension (OR = 5.06; 95% CI = 1.20-21.37) were all independently associated with MetS. In conclusion, low CRF and paternal hypertension significantly increase the risk, whereas breast-feeding may reduce the risk of MetS among Chinese schoolchildren.

Duration of breast-feeding and cardiovascular risk factors among Iranian children and adolescents: the CASPIAN III study

OBJECTIVES

Studies examining the relationship between breast-feeding (BF) duration and cardiovascular disease (CVD) risk factors have reached contradictory results. This study aims to investigate the relationship between BF duration and CVD risk factors in adolescents.

METHODS

This national population-based study was conducted among 5258 Iranian students, ages 10 to 18 y living in central cities of 27 provinces of Iran. Association was examined between duration of BF and adolescent blood pressure, overweight, obesity, and fasting blood glucose and lipid profiles. Analyses were adjusted for potential confounders.

RESULTS

Low birth weight was less frequent in the longer than in the shorter BF duration categories (P < 0.0001). Number of children was lower in individuals with longer BF duration (P = 0.01). Individuals with longer BF duration used more homemade food than those with shorter BF duration (P < 0.0001). Means of total cholesterol and systolic blood pressure were lower in participants with the longest BF period compared with those with the shortest BF duration; this difference was marginally significant (P = 0.06). No significant association was found between BF duration and CVD risk factors in logistic regression after adjustment for potential confounders.

CONCLUSIONS

Although the long-term benefits of BF on preventing CVDs are well documented, controversies exist as to the association of BF duration with such beneficial effects. In this study, there was no substantial evidence that longer BF duration was protective against CVD risk factors among adolescents. More prospective studies are recommended to clarify this association.

Associations of infant nutrition with insulin resistance measures in early adulthood: evidence from the Barry-Caerphilly Growth (BCG) study

Background

Previous studies suggest that over-nutrition in early infancy may programme long-term susceptibility to insulin resistance.

Objective

To assess the association of breast milk and quantity of infant formula and cows' milk intake during infancy with insulin resistance measures in early adulthood.

Design

Long-term follow-up of the Barry Caerphilly Growth cohort, into which mothers and their offspring had originally been randomly assigned, between 1972–1974, to receive milk supplementation or not. Participants were the offspring, aged 23–27 years at follow-up (n = 679). Breastfeeding and formula/cows' milk intake was recorded prospectively by nurses. The main outcomes were insulin sensitivity (ISI₀) and insulin secretion (CIR₃₀).

Results

573 (84%) individuals had valid glucose and insulin results and complete covariate information. There was little evidence of associations of breastfeeding versus any formula/cows' milk feeding or of increasing quartiles of formula/cows' milk consumption during infancy (<3 months) with any outcome measure in young adulthood. In fully adjusted models, the differences in outcomes between breastfeeding versus formula/cows' milk feeding at 3 months were: fasting glucose (−0.07 mmol/l; 95% CI: −0.19, 0.05); fasting insulin (8.0%; −8.7, 27.6); ISI₀ (−6.1%; −11.3, 12.1) and CIR₃₀ (3.8%; −19.0, 32.8). There was also little evidence that increasing intakes of formula/cows' milk at 3 months were associated with fasting glucose (increase per quartile of formula/cows' milk intake = 0.00 mmol/l; −0.03, 0.03); fasting insulin (0.8%; −3.2, 5.1); ISI ₀ (−0.9%; −5.1, 3.5) and CIR₃₀ (−2.6%; −8.4, 3.6).

Conclusions

We found no evidence that increasing consumption of formula/cows' milk in early infancy was associated with insulin resistance in young adulthood.

Breast-feeding and cardiovascular risk factors and outcomes in later life: evidence from epidemiological studies

This paper considers the body of observational evidence examining the association of being breast-fed to cardiovascular risk factors and outcomes in later life, and whether any potentially advantageous findings are causal. Early cardiovascular consequences/correlates of breast-feeding, compared to being formula fed, include markedly higher levels of total blood cholesterol, lower levels of pre-prandial blood glucose and insulin and lower levels of adiposity. However, a key issue is whether these early differences at a period of rapid development programme/influence cardiovascular risk factors and outcomes in later life. Evidence of long-term effects of early feeding, largely from observational studies, has shown that those breast-fed have lower levels of blood total cholesterol, lower risk of type-2 diabetes and marginally lower levels of adiposity and blood pressure in adult life. There is no strong evidence to suggest effects of early feeding on adult levels of blood glucose, blood insulin and CHD outcomes, although further data are needed. However, the influence of confounding factors, such as maternal body size, maternal smoking and socio-demographic factors, and exclusivity of early feeding on these potentially beneficial associations needs to be considered before inferring any causal effects. Moreover, fewer studies have examined whether duration of exclusive breast-feeding has a graded influence on these risk factors and outcomes; such data would help further in deciding upon causal associations. While strong observational evidence suggests nutritional programming of adult cholesterol levels, associations with other markers of cardiometabolic risk and their consequences in later life need to be confirmed in well-conducted observational and experimental studies.

Prevalence of metabolic syndrome in obese children and adolescents using three different criteria and evaluation of risk factors

OBJECTIVE

To compare the prevalence of the metabolic syndrome (MS) in Turkish obese children and adolescents by using three different definitions and to assess the risk factors through a retrospective evaluation of anthropometric and laboratory parameters.

METHODS

Sixty hundred and fourteen obese patients (307 male, 307 female; mean age: 11.3±2.5 years) were included in the study. Medical history, physical examination, anthropometric measurements, results of biochemical and hormonal assays were obtained from the hospital records. MS was diagnosed according to the modified World Health Organization (WHO), Cook and the International Diabetes Federation (IDF) consensus criteria.

RESULTS

The prevalence of MS was found to be 39%, 34% and 33% according to the modified WHO, Cook and the IDF consensus criteria, respectively. MS prevalence in patients aged 12-18 years was significantly higher than that in patients between 7 and 11 years of age (p<0.05). Pubertal patients had a significantly higher MS prevalence than the non-pubertal cases (p<0.05). MS prevalence was also significantly higher in children who had a family history of heart disease, diabetes, obesity and hypertension as well as in those who had not been breast-fed (p<0.05).

CONCLUSION

The use of the modified WHO criteria was found to result in a slightly higher prevalence rate for MS as compared to the other criteria. The prevalence of MS in our study population was higher than that reported in most previous studies in Turkey. A positive family history, puberty and not being breastfed in infancy were shown to be significant risk factors for MS in childhood.

Infant-feeding patterns and cardiovascular risk factors in young adulthood: data from five cohorts in low- and middle-income countries

BACKGROUND

Infant-feeding patterns may influence lifelong health. This study tested the hypothesis that longer duration of breastfeeding and later introduction of complementary foods in infancy are associated with reduced adult cardiovascular risk.

METHODS

Data were pooled from 10 912 subjects in the age range of 15-41 years from five prospective birth-cohort studies in low-/middle-income countries (Brazil, Guatemala, India, Philippines and South Africa). Associations were examined between infant feeding (duration of breastfeeding and age at introduction of complementary foods) and adult blood pressure (BP), plasma glucose concentration and adiposity (skinfolds, waist circumference, percentage body fat and overweight/obesity). Analyses were adjusted for maternal socio-economic status, education, age, smoking, race and urban/rural residence and infant birth weight.

RESULTS

There were no differences in outcomes between adults who were ever breastfed compared with those who were never breastfed. Duration of breastfeeding was not associated with adult diabetes prevalence or adiposity. There were U-shaped associations between duration of breastfeeding and systolic BP and hypertension; however, these were weak and inconsistent among the cohorts. Later introduction of complementary foods was associated with lower adult adiposity. Body mass index changed by -0.19 kg/m(2) [95% confidence interval (CI) -0.37 to -0.01] and waist circumference by -0.45 cm (95% CI -0.88 to -0.02) per 3-month increase in age at introduction of complementary foods.

CONCLUSIONS

There was no evidence that longer duration of breastfeeding is protective against adult hypertension, diabetes or overweight/adiposity in these low-/middle-income populations. Further research is required to determine whether 'exclusive' breastfeeding may be protective. Delaying complementary foods until 6 months, as recommended by the World Health Organization, may reduce the risk of adult overweight/adiposity, but the effect is likely to be small.

Chronic disease and infant nutrition: is it significant to public health?

OBJECTIVE

To assess the public health significance of premature weaning of infants from breast milk on later-life risk of chronic illness.

DESIGN

A review and summary of recent meta-analyses of studies linking premature weaning from breast milk with later-life chronic disease risk is presented followed by an estimation of the approximate exposure in a developed Western country, based on historical breast-feeding prevalence data for Australia since 1927. The population-attributable proportion of chronic disease associated with current patterns of artificial feeding in infancy is estimated.

RESULTS

After adjustment for major confounding variables, current research suggests that the risks of chronic disease are 30-200 % higher in those who were not breast-fed compared to those who were breast-fed in infancy. Exposure to premature weaning ranges from 20 % to 90 % in post-World War II age cohorts. Overall, the attributable proportion of chronic disease in the population is estimated at 6-24 % for a 30 % exposure to premature weaning.

CONCLUSIONS

Breast-feeding is of public health significance in preventing chronic disease. There is a small but consistent effect of premature weaning from breast milk in increasing later-life chronic disease risk. Risk exposure in the Australian population is substantial. Approximately 90 % of current 35-45-year-olds were weaned from breast-feeding by 6 months of age. Encouraging greater duration and exclusivity of breast-feeding is a potential avenue for reducing future chronic disease burden and health system costs.

Do early life exposures explain associations in mid-adulthood between workplace factors and risk factors for cardiovascular disease?

BACKGROUND

Workplace factors (night work, long working hours, psychosocial work stress) have been reported to be associated with increased risk of cardiovascular disease (CVD). We investigated whether (i) workplace factors are associated with CVD risk factors independently of each other, (ii) workplace factors interact, thereby modifying associations and (iii) associations are explained by early life exposures.

METHODS

A total of 7916 employed participants in the 1958 British birth cohort underwent a clinical assessment at age 45 years. Regression analysis was used to examine associations between workplace factors and CVD risk factor levels with adjustment for early life exposures.

RESULTS

Night work was associated with adverse levels of most CVD risk factors. Working > or =48 h/week was positively associated with body mass index (BMI) and waist circumference (WC). Low job control was positively associated with glycosylated haemoglobin (HbA1c) and inflammatory factors, and inversely associated with high-density lipoprotein (HDL)-cholesterol. Low demands were positively associated with systolic blood pressure (SBP), triglycerides and inflammatory factors and inversely associated with HDL-cholesterol. Several associations were weakened when workplace factors were adjusted for each other. Night workers in low-demand jobs had higher BMI [0.78 kg/m(2); 95% confidence interval (CI) 0.35, 1.21], WC (1.49 cm; 0.45, 2.52) and SBP (1.38 mmHg; -0.04, 2.81). HDL was lower for low control plus night work (-0.04 mmol/l; -0.08, -0.01) or long hours (-0.12; -0.18, -0.69). Adjustment for early life exposures explained 30-50% of most associations, e.g. night work/low demands associations reduced by 50% for BMI and WC, and by 39% for SBP.

CONCLUSIONS

Associations between workplace factors and CVD risk factors in mid-adulthood arise in part from social and health disadvantage originating earlier in life.

Breastfeeding in infancy and adult cardiovascular disease risk factors

BACKGROUND

Public health recommendations advocate breastfeeding in infancy as a means to reduce obesity in later life. Several prior studies relating breastfeeding to cardiovascular risk factors have been limited by lack of adjustment for maternal and participant confounding factors.

METHODS

We ascertained breastfeeding history via questionnaire from mothers enrolled in the Framingham Offspring Study. In their young to middle-aged adult children enrolled in the Framingham Third Generation, we examined the relations between maternal breastfeeding history (yes, no) and cardiovascular risk factors, including body mass index (BMI), high-density lipoprotein (HDL) cholesterol, total cholesterol, triglycerides, fasting blood glucose, and systolic and diastolic blood pressure levels. We applied generalized estimating equations to account for sibling correlations and adjusted for maternal and participant lifestyle, education, and cardiovascular risk factors.

RESULTS

In Third Generation participants (n = 962, mean age = 41 years, 54% were women), 26% of their mothers reported breastfeeding. Compared with non-breastfed individuals, breastfed adult participants had lower multivariable-adjusted BMI (26.1 kg/m2 vs 26.9 kg/m2, P = .04) and higher HDL cholesterol levels (HDL 56.6 mg/dL vs 53.7 mg/dL, P = .01). On additional adjustment for BMI, the association between breastfeeding and HDL cholesterol was attenuated (P = .09). Breastfeeding was not associated with total cholesterol, triglycerides, fasting blood glucose, systolic blood pressure, or diastolic blood pressure.

CONCLUSION

Breastfeeding in infancy is inversely associated with adult BMI and positively associated with HDL cholesterol. Associations between breastfeeding and BMI may mediate the association between breastfeeding and HDL cholesterol.

Impact of growth patterns and early diet on obesity and cardiovascular risk factors in young children from developing countries

Non-communicable chronic diseases are now a worldwide epidemic. Diet and physical activity throughout life are among its main determinants. In countries undergoing the early stages of the nutrition transition weight gain from birth to 2 years of life is related to lean mass gain, while ponderal gain after age 2 years is related to adiposity and later diabetes and CVD risk. Evidence from developing countries undergoing the more advanced stages of the nutrition transition is limited. The early growth patterns of a cohort of Chilean children born in 2002 with normal birth weight who at 4 years had a high prevalence of obesity and CVD risk factors have been assessed. Results indicate that BMI gain in early life, particularly from 6 months to 24 months, is positively associated with adiposity and CVD risk status at 4 years. These results together with existing evidence suggest that actions to prevent obesity and nutrition-related chronic diseases in developing countries should start early in life, possibly after 6 months of age. This approach should consider assessing the effect of mode of feeding and the amount and type of energy fed, as well as the resulting growth patterns. The challenge for researchers addressing the nutrition transition is to define the optimal nutrition in early life, considering not only the short- and long-term health consequences but also taking into account the stage of the nutritional transition for the given population of interest. The latter will probably require redefining optimal postnatal growth based on the context of maternal size and fetal growth.

Metabolic programming: Role of nutrition in the immediate postnatal life

Although genes and dietary habits are generally implicated in the aetiology of the prevailing obesity epidemic, the steep increase in the incidence of obesity within a relatively short span of time suggests that other contributing factors may be at play. The role of nutritional experience during the very early periods of life is increasingly being recognized as contributing to growth and metabolic changes in later life. Epidemiological data and studies from animal models have established a strong correlation between an aberrant intrauterine environment and adult-onset disorders in offspring. The nutritional experience in the immediate postnatal life is another independent factor contributing to the development of metabolic diseases in adulthood. Although studies on the small-litter rat model have shown that overnourishment during the suckling period results in adult-onset metabolic disorders, our studies have shown that a change in the quality of calories-specifically, increased carbohydrate intake by newborn rat pups in the immediate postnatal period-results in chronic hyperinsulinaemia and adult-onset obesity. Several functional alterations in islets and in the hypothalamic energy homeostatic mechanism appear to support this phenotype. Remarkably, female rats that underwent the high-carbohydrate dietary modification as neonates spontaneously transmitted the obesity phenotype to their offspring, thus establishing a vicious generational effect. The high-carbohydrate diet-fed rat model has particular relevance in the context of the current human infant feeding practices: reduction in breast feeding and increase in formula feeding for infants, accompanied by early introduction of carbohydrate-enriched baby foods.

[Birth weight and metabolic syndrome in adults: meta-analysis]

OBJECTIVES

To assess published evidences of the effect of birth weight on metabolic syndrome in adults.

METHODS

PubMed and LILACS databases were searched for articles published from 1966 through May 2006. The terms used were: "birth weight", "birthweight", "intra-uterine growth restriction (IUGR)", "fetal growth retardation", "metabolic syndrome", "syndrome X", "Reaven's X syndrome". Two hundred and twenty-four studies reporting estimates of the association between birth weight and metabolic syndrome or its components were considered eligible. Eleven studies provided odds ratios and were included in the meta-analysis.

RESULTS

All but two studies reported an inverse relationship between birth weight and metabolic syndrome. A comparison between low birth weight vs. normal birth weight subjects showed the random effects odds ratio for metabolic syndrome was 2.53 (95% CI: 1.57;4.08). The funnel plot graphic suggests a publication bias but, even in the studies with more than 400 subjects, the results remained significant (pooled odds ratio: 2.37 (95% CI: 1.15;4.90).

CONCLUSIONS

Low birth weight increases the risk of metabolic syndrome in adults.

Factors associated with the metabolic syndrome in a national sample of youths: CASPIAN Study

BACKGROUND AND AIM

To date, research on the influence of environmental factors on metabolic syndrome (MS) among youths is limited. This study was conducted to investigate for the first time the association of these factors with MS in a large national, representative sample of children from a non-Western population.

METHODS AND RESULTS

The study population comprised of 4811 students (2248 boys and 2563 girls) aged 6-18 years, living in six different provinces in Iran. MS, defined based on criteria analogous to those of the Adult Treatment Panel III, was detected in 14.1% of participants. A birth weight of >4000 g in boys and <2500 g in girls increased the risk of having the MS [OR, 95% CI: 1.4 (1.007, 2.05) and 1.2 (1.1, 1.4), respectively]. Poorly educated parents and a positive parental history of chronic disease were other risks factors associated with MS. Low levels of physical activity significantly increased the risk of having MS [boys: 1.3 (1.1, 1.7); girls: 1.4 (1.2, 1.6)]. The risk of MS increased in-line with the consumption of solid hydrogenated fat [boys: 1.2 (1.07, 1.3); girls, 1.3 (1.1, 1.5)] and bread made with white flour [boys: 1.6 (1.3, 2.1); girls, 1.4 (1.1, 1.7)]. In contrast, an increased frequency of consumption of fruits and vegetable, as well as dairy products decreased the risk of having MS.

CONCLUSION

Considering the effect of modifiable lifestyle habits and birth weight on MS in youths, urgent public health approaches should be directed towards primordial and primary prevention of this rapidly growing problem.

Associations of birth size and duration of breast feeding with cardiorespiratory fitness in childhood: findings from the Avon Longitudinal Study of Parents and Children (ALSPAC)

OBJECTIVES

To explore the developmental origins of cardiorespiratory fitness.

METHODS

We examined the associations of birth size and duration of breast feeding with cardiorespiratory fitness assessed at the 9 year follow-up examination in 3612 participants of the Avon Longitudinal Study of Parents and Children (ALSPAC). We used physical work capacity at a heart rate of 170 beats per minute (PWC(170)) as our assessment of cardiorespiratory fitness. This was estimated using standard regression methods from parameters measured using an electronically braked cycle ergometer.

RESULTS

Birth weight, length and ponderal index were all positively associated with cardiorespiratory fitness in both sexes, with no strong evidence of a difference in effect between girls and boys. Work capacity increased by 1.12 W (95% CI: 0.83, 1.40) on average per 1 standard deviation (SD) greater birth weight. This association was not affected by adjustment for socioeconomic position and maternal smoking during pregnancy; there was some attenuation with adjustment for both maternal and paternal height and body mass index and more marked attenuation with adjustment for the child's height and body mass index. In the fully adjusted model work capacity increased by 0.51 W (95% CI: 0.21, 0.81) per SD birth weight. Whether an individual had been breastfed and duration of breastfeeding were not associated with cardiorespiratory fitness in any models.

CONCLUSION

Our results provide some support for a role of intrauterine factors in determining cardiorespiratory fitness in childhood.

Metabolic programming in the immediate postnatal period

In recent decades, there has been a dramatic increase in the incidence of obesity in all age groups of the population in the USA. In addition to genetics and life style changes, the important role of metabolic programming effects in the etiology of the obesity epidemic is being increasingly recognized. Although the role of a compromised intrauterine environment in fetal metabolic programming is well documented to contribute to the development of adult-onset diseases, vulnerability in the immediate postnatal period to similar conditions has also been shown. Metabolic programming effects induced by altered nutritional experiences in the immediate postnatal period can give rise to long-term consequences in the context of the current obesity epidemic.

Tobacco smoke exposure of pregnant mothers and blood pressure in their newborns: results from the wheezing illnesses study Leidsche Rijn birth cohort

There is evidence to suggest that exposure of pregnant women to tobacco smoke is related to higher childhood blood pressure in their offspring. It is not well known whether this association is set in utero or by shared postnatal environments. The objective of this study was to assess the association between tobacco smoke exposure of pregnant mothers and blood pressure and heart rate of their newborns. In an unselected birth cohort, blood pressure and heart rate were measured in 456 infants at approximately 2 months of age. Smoking exposure of mothers in pregnancy was obtained by questionnaire. Of 456 mothers whose infants had blood pressure measured, 363 (79.6%) were not exposed to tobacco smoke in pregnancy, 63 (13.8%) did not smoke in pregnancy but were exposed by others, and 30 (6.6%) smoked. Infant offspring of mothers who had smoked during pregnancy had 5.4 mm Hg (95% CI: 1.2 to 9.7; P=0.01) higher systolic blood pressure levels than offspring of mothers who were not exposed to tobacco smoke in pregnancy, taking account of birth weight, infant age, gender, nutrition, and age of mother. No associations were found between maternal exposure to tobacco smoke in pregnancy and diastolic blood pressure. A positive association between maternal exposure to tobacco smoke and heart rate was largely explained by confounding. It can be concluded that maternal exposure to tobacco smoke in pregnancy has a substantial increasing effect on systolic blood pressure in early infancy.

The effect of breastfeeding on cardiorespiratory risk factors in adult life

OBJECTIVE

Nutrition in the first weeks of life may program disease risk in adulthood. We examined the influence of initial infant feeding on cardiorespiratory risk factors in adulthood.

PATIENTS AND METHODS

A total of 9377 persons born during 1 week in 1958 in England, Scotland, and Wales were followed-up periodically from birth into adulthood. Infant feeding was recorded from a parental questionnaire at 7 years old as never breastfed, breastfed partially or wholly for <1 month, or breastfed for >1 month. Height; waist circumference; hip circumference; waist/hip ratio; body mass index; blood pressure; forced expiratory volume; total, high-density, and low-density lipoprotein cholesterol; triglycerides; hemoglobin A1c; fibrinogen; fibrin D-dimer; C-reactive protein; von Willebrand factor; and tissue plasminogen activator antigen were measured at 44 to 45 years of age.

RESULTS

Breastfeeding for >1 month was associated with reduced waist circumference, waist/hip ratio, von Willebrand factor, and lower odds of obesity compared with formula feeding after adjustment for birth weight, prepregnancy maternal weight, maternal smoking during pregnancy, socioeconomic position in childhood and adulthood, region of birth, gender, and current smoking status. Infant feeding status was not associated with other cardiorespiratory risk factors after adjustment, except for lower fibrinogen and C-reactive protein levels in women.

CONCLUSIONS

The inverse associations of breastfeeding for >1 month with measures of central obesity and inflammatory markers in the current study are small and of little public health importance. Although there was no substantial long-term protective effect of breastfeeding for >1 month on other cardiorespiratory risk factors in adult life, further studies with contemporaneous data on exclusive breastfeeding are needed to confirm these findings.

Does breastfeeding influence risk of type 2 diabetes in later life? A quantitative analysis of published evidence

BACKGROUND

Observational evidence suggests that having been breastfed in infancy may reduce the prevalence of type 2 diabetes in later life.

OBJECTIVE

The objective was to examine the influence of initial breastfeeding on type 2 diabetes and blood glucose and insulin concentrations.

DESIGN

A systematic review of published studies identified 1010 reports; 23 examined the relation between infant feeding and type 2 diabetes in later life or risk factors for diabetes. Risk factors in infants were examined separately from those in children and adults. All estimates were pooled by using fixed-effect models; differences <0 and ratios <1 imply a beneficial effect of breastfeeding.

RESULTS

Subjects who were breastfed had a lower risk of type 2 diabetes in later life than did those who were formula fed (7 studies; 76 744 subjects; odds ratio: 0.61; 95% CI: 0.44, 0.85; P = 0.003). Children and adults without diabetes who had been breastfed had marginally lower fasting insulin concentrations than did those who were formula fed (6 studies; 4800 subjects; percentage difference: -3%; 95% CI: -8%, 1%; P = 0.13); no significant difference in fasting glucose concentrations was observed. Breastfed infants had lower mean preprandial blood glucose (12 studies; 560 subjects; mean difference: -0.17 mmol/L; 95% CI: -0.28, -0.05 mmol/L; P = 0.005) and insulin (7 studies; 291 subjects; mean difference: -2.86 pmol/L; 95% CI: -5.76, 0.04 pmol/L; P = 0.054) concentrations than did those who were formula fed.

CONCLUSION

Breastfeeding in infancy is associated with a reduced risk of type 2 diabetes, with marginally lower insulin concentrations in later life, and with lower blood glucose and serum insulin concentrations in infancy.

Physical activity and clustered cardiovascular risk in children: a cross-sectional study (The European Youth Heart Study)

BACKGROUND

Atherosclerosis develops from early childhood; physical activity could positively affect this process. This study's aim was to assess the associations of objectively measured physical activity with clustering of cardiovascular disease risk factors in children and derive guidelines on the basis of this analysis.

METHODS

We did a cross-sectional study of 1732 randomly selected 9-year-old and 15-year-old school children from Denmark, Estonia, and Portugal. Risk factors included in the composite risk factor score (mean of Z scores) were systolic blood pressure, triglyceride, total cholesterol/HDL ratio, insulin resistance, sum of four skinfolds, and aerobic fitness. Individuals with a risk score above 1 SD of the composite variable were defined as being at risk. Physical activity was assessed by accelerometry.

FINDINGS

Odds ratios for having clustered risk for ascending quintiles of physical activity (counts per min; cpm) were 3.29 (95% CI 1.96-5.52), 3.13 (1.87-5.25), 2.51 (1.47-4.26), and 2.03 (1.18-3.50), respectively, compared with the most active quintile. The first to the third quintile of physical activity had a raised risk in all analyses. The mean time spent above 2000 cpm in the fourth quintile was 116 min per day in 9-year-old and 88 min per day in 15-year-old children.

INTERPRETATION

Physical activity levels should be higher than the current international guidelines of at least 1 h per day of physical activity of at least moderate intensity to prevent clustering of cardiovascular disease risk factors.

The relation between components of adult height and intimal-medial thickness in middle age: the Atherosclerosis Risk in Communities Study

The authors aimed to investigate the relation between components of adult height (leg and trunk length) and atherosclerosis in middle age, using data from 12,254 participants (aged 44-65 years) in the Atherosclerosis Risk in Communities (ARIC) Study. Intimal-medial thickness (IMT) as measured by B-mode ultrasound was the outcome, and exposures were trunk and leg lengths as estimated (using sitting height and the difference between sitting and standing height) at the first study examination in 1987-1989. The mean IMT was 0.73 (standard deviation, 0.17) mm. Greater leg length was associated with lower IMT, with the largest difference being for Black men (a 0.045 (95% confidence interval: 0.023, 0.068)-mm lower IMT per 10-cm higher leg length). Greater trunk length was associated with higher IMT, with the largest difference being for White men (a 0.024 (95% confidence interval: 0.005, 0.044)-mm higher IMT per 10-cm higher trunk length). Although the effect sizes were small, leg length was inversely associated with atherosclerosis, consistent with the results of other studies with cardiovascular disease outcomes.

Perinatal and childhood origins of cardiovascular disease

BACKGROUND

Features of the metabolic syndrome comprise a major risk for cardiovascular disease and will increase in prevalence with rising childhood obesity. We sought to identify early life influences on development of obesity, hypertension and dyslipidemia in children.

METHODS AND RESULTS

Cluster analysis was used on a subset of a longitudinal Australian birth cohort who had blood samples at age 8 (n=406). A quarter of these 8-year-olds fell into a cluster with higher body mass index, blood pressure (BP), more adverse lipid profile and a trend to higher serum glucose resembling adult metabolic syndrome. There was a U-shaped relationship between percentage of expected birth weight (PEBW) and likelihood of being in the high-risk cluster. The high-risk cluster had elevated BP and weight as early as 1 and 3 years old. Increased likelihood of the high-risk cluster group occurred with greatest weight gain from 1 to 8 years old (odds ratio (OR)=1.4, 95% confidence interval (CI)=1.3-1.5/kg) and if mothers smoked during pregnancy (OR=1.82, CI=1.05-3.2). Risk was lower if children were breast fed for >/=4 months (OR=0.6, 95% CI=0.37-0.97). Newborns in the upper two quintiles for PEBW born to mothers who smoked throughout pregnancy were at greatest risk (OR=14.0, 95% CI=3.8-51.1) compared to the nadir PEBW quintile of non-smokers.

CONCLUSION

A U-shaped relationship between birth weight and several components of the metabolic syndrome was confirmed in a contemporary, well-nourished Western population of full-term newborns, but post-natal weight gain was the dominant factor associated with the high-risk cluster. There was a prominence of higher as well as lowest birth weights in those at risk. Future health programs should focus on both pre- and post-natal factors (reducing excess childhood weight gain and smoking during pregnancy), and possibly the greatest benefits may arise from targeting the heaviest, as well as lightest newborns, especially with a history of maternal smoking during pregnancy.

Breast feeding and future health

PURPOSE OF REVIEW

This review discusses the long-term health effects of breast feeding, based on the most relevant publications from the second half of 2004 and 2005.

RECENT FINDINGS

The positive effect of breast feeding on later cognitive function continues to be the most consistent and important effect. Also, breast feeding is likely to protect against some immune-related diseases later in life, such as type 1 diabetes, coeliac disease, inflammatory bowel diseases and perhaps cancer. The evidence for an effect on allergic disease continues to be inconclusive. Furthermore, breast feeding seems to be associated with a lower blood pressure and serum cholesterol, but there is no clear association with cardiovascular disease or death. Most new studies and meta-analyses show a protective effect against later obesity, but this seems to be small. A new hypothesis suggests that breast feeding programmes the insulin-like growth factor axis and results in higher growth velocity later in childhood.

SUMMARY

Evidence is increasing that breast feeding, beyond its well-established beneficial effects during the breast-feeding period, also confers long-term benefits. These effects are not strong at the individual level, but are likely to be of importance at the population level. Since the majority of the studies are observational, however, it is difficult to prove causality.

Breastfeeding duration and blood pressure among Brazilian adolescents

OBJECTIVE

To assess the relationship between breastfeeding duration and blood pressure in a large birth cohort of Brazilians followed from birth to adolescence.

METHODS

All 5914 hospital births occurring in Pelotas in 1982 (over 99% of all deliveries) were studied prospectively. Detailed information on feeding practices was prospectively collected during childhood. In 1997 and 2001 we attempted to trace a sample of the cohort, whereas in 2000 we identified the male subjects when presenting for the army recruitment exam. Blood pressure measurements were taken in 1997 for both sexes, males in 2000 and females in 2001.

RESULTS

Information on breastfeeding collected between 1983 and 1986 was available for 90.8% of the 5914 original cohort subjects. We managed to follow 1076, 2250 and 1031 subjects in 1997, 2000 and 2001, respectively. Total breastfeeding duration was not associated with systolic and diastolic blood pressure in adolescence. Diastolic blood pressure at the age of 15 y (1997) was higher among girls who had been predominantly breastfed for at least 4 mo. After controlling for confounding variables (family income, maternal education at birth and maternal BMI at birth, skin colour, birthweight, gestational age, maternal smoking during pregnancy, adolescent smoking and alcohol drinking), the strength of the association was reduced and the 95% confidence interval encompassed the other blood pressure estimates. Furthermore, such association was not replicated in the 2001 follow-up visit.

CONCLUSION

Breastfeeding duration was not related to blood pressure in adolescence.

Growth and breastfeeding among low birth weight infants fed with or without protein enrichment of human milk

The effect of protein enrichment of mother's milk on growth of low birthweight infants needs further exploration in order to optimize feeding strategies. The aim of this study was to describe feeding and growth of infants weighing <1,900 g at birth, up to a corrected age of 18 months, with or without protein-enriched breastmilk. A retrospective, descriptive, non-experimental design was used to describe the growth of 52 low birthweight infants. Data on their growth and feeding were collected from medical records at hospitals and child health care clinics. Despite more severe morbidity, the infants given protein-enriched milk showed similar growth as the other study infants. Standard deviation score for length at birth correlated positively with delta standard deviation score for length, from discharge to 12 and from discharge to 18 months corrected age. Duration of 'full' breastfeeding had a significant impact on subsequent improvement in SDS for weight. At discharge a smaller proportion of singletons fed with protein enriched milk were breastfed 'fully'. Infants who established breastfeeding at an early post-menstrual age were born with more optimal weight standard deviation score and had a better weight gain after discharge. We conclude that protein-enriched breast milk enables low birthweight infants requiring especially intensive care to attain growth at discharge comparable to that of healthier infants not given enriched milk. Low standard deviation score for length at birth may predict poor growth after discharge. However duration of 'full' breastfeeding had a significant impact on subsequent improvement in SDS for weight. Therefore it is important that mothers of LBW infants are given sufficient support of lactation and breastfeeding.