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 < or =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 < or =2 months compared with those exclusively breast-fed for > or =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.

Long term effects of breastfeeding on the infant and mother.

There is increasing evidence that breastfeeding has long term beneficial effects on the infant. The most important are improved cognitive development, reduced incidence of immune related diseases (e.g. Type-1 diabetes and inflammatory bowel disease), and childhood cancers. A reduced risk of breast cancer in the mother is another important benefit.

[Children, fat and cardiovascular diseases]. / Børn, fedt og hjerte-kar-sygdomme.

Children do not normally develop atherosclerosis. However, they do develop fatty streaks in the aorta. These are reversible. During the first years of life dietary fat has an influence on blood lipids, and other traditional risk factors influence vascular function, but the consequences are unknown. As saturated fat has no positive effects, the Danish Nutrition Council recommends that the intake of saturated fat is reduced to 10 energy per cent from the age of 12 months. This can be accomplished with semi-skimmed milk (1.5% fat) instead of full-cream milk. During the first year of life, it is recommended that a teaspoon of fat is added to each serving of home made mashed food or porridge to prevent the diet from being so hypocaloric that it has a negative effect on growth.

Late introduction of complementary feeding, rather than duration of breastfeeding, may protect against adult overweight.

BACKGROUND: Early nutrition may affect the risk of overweight in later life. OBJECTIVE: The objective was to explore the effect of the duration of breastfeeding (BF) and age at introduction of complementary feeding (CF) on body mass index (BMI) during childhood through adulthood. DESIGN: The study was based on a subsample of the Copenhagen Perinatal Cohort established in 1959-1961 (n = 5068). Information on BF and available information on CF (age of introduction of "spoon-feeding," "vegetables," "egg," "meat," and "firm food") and several covariates were collected in infancy and linked with information on BMI from follow-up examinations in childhood and adulthood at age 42 y. RESULTS: The median (10th, 90th percentiles) durations of any BF and age at introduction of spoon-feeding were 2.50 (0.23, 6.50) and 3.50 (2.00, 6.00) mo, respectively. After 1 y of age and throughout childhood and adolescence, no association between BF and BMI was found in regression models also adjusted for age at introduction of spoon-feeding and covariates. The risk of overweight at age 42 y decreased or tended to decrease with increasing age (in mo) at introduction of spoon-feeding [odds ratio (OR): 0.94; 95% CI: 0.86, 1.02], vegetables (OR: 0.90; 95% CI: 0.81, 0.98), meat (OR: 0.93; 95% CI: 0.87, 1.00), and firm food (OR: 0.92; 95% CI: 0.86, 0.98) but not egg (OR: 0.98; 95% CI: 0.91, 1.05). CONCLUSION: The findings of this study suggest that introduction of CF at a later age (within the range of 2 to 6 mo) is protective against overweight in adulthood but do not support a protective effect of a longer duration of BF.

Effect of growth in infancy on body composition, insulin resistance, and concentration of appetite hormones in adolescence.

BACKGROUND: High infancy weight gain is associated with increased body mass index (BMI) and insulin resistance (IR) in later life, but the association with later body composition has not been well explored. Appetite regulatory hormones may be programmed in early life, but data to support this are lacking. OBJECTIVE: We investigated the effect of weight gain in infancy on body composition, IR, leptin, ghrelin, and adiponectin at 17 y of age. DESIGN: This was an observational study of 95 term and appropriate-for-gestational-age infants. We measured weight at birth and 9 mo of age and, for a subgroup (n = 60), at 3 and 6 mo of age. Changes in weight SD scores from 0 to 9, 0 to 3, 3 to 6, and 6 to 9 mo of age were calculated. Follow-up examinations at 10 and 17 y of age included body fat (BF) assessment by dual-energy X-ray absorptiometry scanning. We measured serum leptin, ghrelin adiponectin, and IR at 17 y of age. RESULTS: Weight gain from 0 to 9 mo of age was positively associated with BMI (P < 0.003), percentage BF (P < 0.05), and percentage trunk fat (TF) (P < 0.03) but not with percentage TF relative to total BF, in childhood and adolescence, and most of these effects were explained by growth from 0 to 3 mo of age. Weight gains from 0 to 9 and 0 to 3 mo of age were not related to IR or leptin but were negatively associated with ghrelin and adiponectin corrected for BF at 17 y of age. CONCLUSION: Our findings suggest that high weight gain in infancy, especially from 0 to 3 mo of age, has a role in programming both BF and concentrations of ghrelin and adiponectin in adolescence, whereas there was no effect on IR or leptin in this study.

Early programming of the IGF-I axis: negative association between IGF-I in infancy and late adolescence in a 17-year longitudinal follow-up study of healthy subjects.

BACKGROUND: IGF-I is a major regulator of growth, influenced primarily by diet in infancy and primarily by GH in childhood. Breastfed infants have lower IGF-I levels compared to formula fed and tend to be shorter. The higher protein content of infant formula has a stimulatory effect on IGF-I production. Conversely, studies suggest that later in childhood, those breastfed are taller and have higher IGF-I levels. Therefore, it has been suggested that the IGF-I axis may be programmed by diet during infancy. The association between IGF-I in infancy and later life is not known. OBJECTIVE: To examine the association between IGF-I in infancy and adolescence. DESIGN: Infants (109) from the observational Copenhagen cohort study. METHODS: Serum-IGF-I was measured during infancy (2, 6, and 9 months) and at follow-up at 17 years. Associations were examined by correlation tests and linear regression controlling for gender, breastfeeding, and other covariates. Likelihood ratio test based on residual log likelihood was applied for analysis including all measurements during infancy. RESULTS: There was an inverse association between IGF-I at 9 months and 17 years (r=-0.39, P=0.014, and n=40). A 1 ng/ml higher IGF-I concentration at 9 months corresponded to 0.95 ng/ml lower IGF-I concentration at 17 years. IGF-I levels at 2 and 6 months were not significantly associated with IGF-I at 17 years, but the estimated directions were negative. These associations were not changed when adjusted for breastfeeding and other covariates except IGF-I at 2 months which was significantly negatively associated with IGF-I at 17 years (P=0.030) corresponding to a 0.96 ng/ml lower IGF-I concentration at 17 years per ng/ml IGF-I at 2 months. Inclusion of all measurements during infancy showed a negative association with 17-year values (r=-0.26, P=0.043, and n=109). CONCLUSION: The results support the hypothesis that the IGF-I axis can be programmed early in life.

Nuclear magnetic resonance-based metabonomics reveals strong sex effect on plasma metabolism in 17-year-old Scandinavians and correlation to retrospective infant plasma parameters.

Nuclear magnetic resonance (NMR)-based metabonomics was carried out on plasma samples from a total of seventy-five 17-year-old Danes to investigate the impact of key parameters such as sex, height, weight, and body mass index on the plasma metabolite profile in a normal, healthy population. Principal component analysis identified sex to have a large impact on the NMR plasma metabolome, whereas no apparent effects of height, weight, and body mass index were found. Partial least square regression discriminant analysis and quantification of relative metabolite concentrations by integration of NMR signals revealed that the sex effect included differences in plasma lipoproteins (mainly high-density lipoprotein), glucose, choline, and amino acid content. Accordingly, the present study suggests a higher lipid synthesis in young women than young men and a higher protein turnover in young men compared with women. Data on plasma content of triglyceride, lipoprotein fractions, and cholesterol at an age of 9 months were available for selected individuals (n = 40); and partial least square regressions revealed correlations between these infant parameters and the NMR plasma metabolome at an age of 17 years. In conclusion, the present study demonstrates the feasibility of NMR-based metabonomics for obtaining a deeper insight into interindividual differences in metabolism and for exploring relationships between parameters measured early in life and metabolic status at a later stage.

Birth weight in relation to leisure time physical activity in adolescence and adulthood: meta-analysis of results from 13 nordic cohorts.

BACKGROUND: Prenatal life exposures, potentially manifested as altered birth size, may influence the later risk of major chronic diseases through direct biologic effects on disease processes, but also by modifying adult behaviors such as physical activity that may influence later disease risk. METHODS/PRINCIPAL FINDINGS: We investigated the association between birth weight and leisure time physical activity (LTPA) in 43,482 adolescents and adults from 13 Nordic cohorts. Random effects meta-analyses were performed on categorical estimates from cohort-, age-, sex- and birth weight specific analyses. Birth weight showed a reverse U-shaped association with later LTPA; within the range of normal weight the association was negligible but weights below and above this range were associated with a lower probability of undertaking LTPA. Compared with the reference category (3.26-3.75 kg), the birth weight categories of 1.26-1.75, 1.76-2.25, 2.26-2.75, and 4.76-5.25 kg, had odds ratios of 0.67 (95% confidence interval: 0.47, 0.94), 0.72 (0.59, 0.88), 0.89 (0.79, 0.99), and 0.65 (0.50, 0.86), respectively. The shape and strength of the birth weight-LTPA association was virtually independent of sex, age, gestational age, educational level, concurrent body mass index, and smoking. CONCLUSIONS/SIGNIFICANCE: The association between birth weight and undertaking LTPA is very weak within the normal birth weight range, but both low and high birth weights are associated with a lower probability of undertaking LTPA, which hence may be a mediator between prenatal influences and later disease risk.

Advances in our understanding of the biology of human milk and its effects on the offspring.

There is an intense interest in the effects of breast-feeding on the offspring and in understanding the mechanisms behind these effects. More than 50 papers are published monthly on topics such as the influence of breast-feeding on aspects of growth, immune-related effects, mental development, and noncommunicable diseases. Most breast-feeding data are observational; confounding can be difficult to rule out because some maternal factors are associated with both breast-feeding and infant outcomes (e.g., obesity and mental development). The most important short-term immunological benefit of breast-feeding is the protection against infectious diseases. There is also some evidence of lower prevalence of inflammatory bowel diseases, childhood cancers, and type I diabetes in breast-fed infants, suggesting that breast-feeding influences the development of the infant's own immune system. One of the most consistent findings of breast-feeding is a positive effect on later intelligence tests with a few test points advantage for breast-fed infants. In the last few years, several systematic reviews and meta-analyses have examined the effect of breast-feeding on noncommunicable diseases. There seems to be a small protective effect against later overweight and obesity. Blood pressure and blood cholesterol seem to be slightly lower in breast-fed infants; however, the few studies examining breast-feeding and the risk of coronary heart disease in later life did not find an association. Recent data have suggested that breast-feeding can program the insulin-like growth factor-I axis, as 3 studies found that breast-fed infants are taller as adults.

[The effects of breastfeeding I: effects on the immune system and the central nervous system]. / Amningens effekter. I: Betydning for immunsystem og centralnervesystem.

In this first of two reviews, the focus is on the effect of breastfeeding on the immune system and the central nervous system. Human milk contains immune factors that protect the child against infections and stimulate the child's own immune system. This could explain the fact that breastfeeding is associated with reduced risk of certain allergic disorders, celiac disease, type 1-diabetes and inflammatory bowel diseases. Furthermore, breastfed infants have a better visual acuity during infancy and a slightly better cognitive function later in life.

[The effects of breastfeeding II: effects on lifestyle illnesses, mother's health and negative effects]. / Amningens effekter. II: betydning for livsstilssygdomme, negative effekter og moderens sundhed.

Growth during infancy is slightly lower among breastfed infants, but the difference seems to disappear later during childhood. Breastfeeding seems to have a beneficial effect on blood pressure, lipid profile and possible insulin resistance/type-2 diabetes and obesity, but there is no evidence for effects on clinical manifestations of cardiovascular diseases. Potential negative effects include transfer of environmental pollutants and viruses, especially HIV, and the risk of hypernatraemic dehydration during the first weeks after delivery. For the mother, breastfeeding seems to reduce the risk of developing breast cancer.

Birth weight and systolic blood pressure in adolescence and adulthood: meta-regression analysis of sex- and age-specific results from 20 Nordic studies.

The authors investigated the shape, sex- and age-dependency, and possible confounding of the association between birth weight and systolic blood pressure (SBP) in 197,954 adults from 20 Nordic cohorts (birth years 1910-1987), one of which included 166,249 Swedish male conscripts. Random-effects meta-regression analyses were performed on estimates obtained from age- and sex-stratified analyses within each of the cohorts. There was an inverse association between birth weight and SBP, irrespective of adjustment for concurrent body mass index. The association was linear for males, but for females with a birth weight greater than 4 kg, SBP increased with birth weight (p < 0.01). The association was stronger in the older age groups (p < 0.05), although this could have been a birth cohort effect. The association was stronger among females than among males (p = 0.005) when birth weight was less than or equal to 4 kg. The estimated effect of birth weight on SBP at age 50 years was -1.52 mmHg/kg (95% confidence interval: -2.27, -0.77) in men and -2.80 mmHg/kg (95% confidence interval: -3.85, -1.76) in women. Exclusion of the Swedish conscripts produced nearly identical results. This meta-analysis supports the evidence of an inverse birth weight-SBP association, regardless of adjustment for concurrent body size. It also reveals important heterogeneity in the shape and strength of the association by sex and age.

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.

Secular change in size at birth from 1973 to 2003: national data from Denmark.

OBJECTIVE: To explore whether birth weight (BW) has been increasing in Denmark at the same level as in other countries and whether this increase is paralleled by an increase in birth length (BL) or whether body proportionality, expressed as ponderal index (PI), has changed. RESEARCH METHODS AND PROCEDURES: This study used data analysis of information from The Danish Medical Birth Registry including all single live births in Denmark from 1973 to 2003 (n = 1,863,456). BW, BL, gestational age, maternal age, and smoking status (only from 1991 on) were measured. RESULTS: Mean BW increased steadily during the period (160 grams; equivalent to approximately 5 g/yr) at a rate higher than that reported from other countries. BL showed only a minor increase (2.4 mm), leading to an increase in PI (0.8 kg/m3) during the period. Controlling for the effect of increasing maternal age and decreasing gestational age and maternal smoking prevalence (only data after 1991), there was still an increase in BW of approximately 4 g/yr. DISCUSSION: During the last 30 years, neonates have become bigger, with a larger relative increase in BW than BL, leading to an increase in PI. The increasing BW and PI, which may be caused by increased maternal weight, could further promote the obesity epidemic.

Fish oil affects blood pressure and the plasma lipid profile in healthy Danish infants.

Animal and epidemiologic studies indicate that early nutrition has lasting effects on metabolism and cardiovascular disease risk. In adults, (n-3) long-chain PUFA (LCPUFA) from fish oils improve blood pressure, the lipid profile, and possibly cardiovascular disease mortality. This randomized trial is the first to investigate the effects of fish oil on blood pressure and the lipid profile in infancy. Healthy term 9-mo old infants (n = 83) were randomly assigned to 5 mL fish oil daily or no fish oil for 3 mo and to 2 different milk types. Before and after the intervention, blood pressure was measured with an oscillometric device, and blood was sampled for analysis of erythrocyte fatty acid composition and the plasma lipid profile. This paper examines the effects of the fish oil supplement, with adjustment for the effects of the milk intervention when relevant. The fish oil intervention increased erythrocyte (n-3) LCPUFA content (P < 0.001). At 12 mo, infants administered fish oil had a lower systolic blood pressure [adjusted mean difference (95% CI)] 6.3 mm Hg (0.9, 11.7) (P = 0.02), a 0.51 mmol/L (0.07, 0.95) higher plasma total cholesterol (P = 0.02), and a 0.52 mmol/L (0.02,1.01) higher LDL cholesterol (P = 0.04) than infants not administered fish oil. Plasma triacylglycerol was inversely associated with the erythrocyte content of eicosapentaenoic acid (r = 0.34, P < 0.01), a biomarker of fish oil dose. The observed effects of fish oil are in accordance with findings in adults. The long-term health implications warrant further investigation.

Arterial stiffness in 10-year-old children: current and early determinants.

It has been suggested that CVD has its origins in early life. An impairment of fetal growth and early postnatal nutrition may have programming effects on cardiovascular physiology. In addition, traditional risk factors for CVD may initiate the atherosclerotic process during childhood. We explored the effect of fat intake, physical activity and lipid profile in childhood, and birth weight, growth during infancy and breast-feeding on arterial stiffness in a cohort study of ninety-three 10-year-old children followed during infancy and re-examined at the age of 10 years. Arterial stiffness in two arterial segments (aorto-radial and aorto-femoral) was measured as pulse wave velocity. Arterial stiffness was inversely associated with physical activity (a regression coefficient in cm/s (95 % CI) of -6.8 (-11.2, -2.4) and -3.9 (-6.9, -0.8) per h of high physical activity/d in the aorto-radial and aorto-femoral segments, respectively). Arterial stiffness was also positively associated with dietary fat energy percentage (3.1 (95 % CI 0.9, 5.2) and 1.8 (95 % CI 0.2, 3.2) per fat energy percentage in the aorto-radial and aorto-femoral segments, respectively) but was not related to body composition, insulin resistance or lipid profile. Arterial stiffness was also positively associated with duration of breast-feeding for the aorto-femoral segment only (2.1 (95 % CI 0.4, 3.7) per month) but was not associated with growth in early life. In conclusion, patterns of physical activity and diet, and history of breast-feeding in infancy, have an influence on the stiffness of the large arteries in children. The long-term effects of this are unknown.

Stability of the association between birth weight and childhood overweight during the development of the obesity epidemic.

OBJECTIVE: To assess whether changes in the birth weight distribution or changes in the association of birth weight with the later risk of childhood overweight have contributed to the development of the obesity epidemic. RESEARCH METHODS AND PROCEDURES: A Danish population-based cohort study of 124,615 girls and 128,346 boys (ages 6 to 13 years), born between 1936 and 1983, were studied. Birth weight and annual measurements of height and weight were obtained from school health records. Overweight was defined by BMI in relation to internationally accepted criteria. The relative risk of being overweight by birth weight was calculated separately for each age, sex, and time period. RESULTS: The birth weight distribution remained relatively stable over time. Compared with children with a birth weight of 3.0 to 3.5 kg, the risk of overweight increased consistently with each increase in birth weight category among girls and boys and at all ages between 6 and 13 years. Furthermore, the association between birth weight and increased risk of overweight in childhood remained stable across a 48-year period. DISCUSSION: The increase in the prevalence of overweight could not be explained by time trends in the distribution of birth weight or by changes in the association between birth weight and the later risk of overweight over time. This implies that, unless the prenatal environment influences the later risk of overweight without increasing birth weight, the environmental influences contributing to the obesity epidemic in children of school age operate in the early postnatal period.