Analysis of the relationship of insulin-like growth factor-1 to the growth velocity and feeding of healthy infants

Dynamic Changes in Serum IGF-I and Growth During Infancy: Associations to Body Fat, Target Height, and PAPPA2 Genotype

CONTEXT

IGF-I is important for postnatal growth and may be of diagnostic value in infants suspected of pituitary disease; however, little is known about the impact of IGF-I and its determinants on infant growth. Importantly, detailed reference ranges for IGF-I and IGF binding protein-3 (IGFBP-3) concentrations during infancy are lacking.

OBJECTIVE

To evaluate the rapid changes in weight and length as well as their determinants in healthy infants, and to establish age- and sex-specific reference curves for IGF-I and IGFBP-3 in children aged 0 to 1 years.

DESIGN

Prospective longitudinal study.

SETTING

Cohort study.

PARTICIPANTS

A total of 233 healthy children (114 girls) with repeated blood samples during the first year of life.

MAIN OUTCOME MEASURE(S)

Serum concentrations of IGF-I and IGFBP-3, length velocity, weight velocity, and PAPPA2 (rs1325598) genotype.

RESULTS

Individual trajectories of length and weight velocities were sex specific. We provide detailed reference curves based on longitudinal data for IGF-I and IGFBP-3 during infancy. In both girls and boys, IGF-I decreased during infancy, whereas IGFBP-3 remained stable. IGF-I and IGFBP-3, but not PAPPA2 genotype, were positively associated with weight gain, but not with longitudinal growth. When stratified by sex, the association between weight gain and IGF-I only remained significant in girls.

CONCLUSIONS

Interestingly, we found a significant association between IGF-I and infant weight gain in girls, but not with longitudinal growth in the first year of life. Our findings highlight the role of IGF-I as an important anabolic hormone that is not limited to linear growth.

Longitudinal Association of Maternal Pre-Pregnancy BMI and Third-Trimester Glycemia with Early Life Growth of Offspring: A Prospective Study among GDM-Negative Pregnant Women

Intrauterine modifiable maternal metabolic factors are essential to the early growth of offspring. The study sought to evaluate the associations of pre-pregnancy BMI and third-trimester fasting plasma glucose (FPG) with offspring growth outcomes within 24 months among GDM-negative pregnant women. Four hundred eighty-three mother –offspring dyads were included from the Shanghai Maternal-Child Pairs Cohort. The pregnant women were categorized into four mutually exclusive groups according to pre-pregnancy BMI as normal or overweight/obesity and third-trimester FPG as controlled or not controlled. Offspring growth in early life was indicated by the BAZ (BMI Z-score), catch-up growth, and overweight/obesity. Among those with controlled third-trimester FPG, pre-pregnancy overweight/obesity significantly increased offspring birth weight, BAZ, and risks of overweight/obesity (RR 1.83, 95% CI 1.23 to 2.73) within 24 months. Those who had uncontrolled third-trimester FPG had a reduced risk of offspring overweight/obesity within 24 months by 47%. The combination of pre-pregnancy overweight/obesity and maternal uncontrolled third-trimester FPG increased 5.24-fold risk of offspring catch-up growth within 24 months (p < 0.05). Maternal pre-pregnancy overweight/obesity and uncontrolled third-trimester glycemia among GDM-negative women both have adverse effects on offspring growth within 24 months. With the combination of increasing pre-pregnancy BMI and maternal third-trimester FPG, the possibility of offspring catch-up growth increases.

Biomarkers of environmental enteric dysfunction are not consistently associated with linear growth velocity in rural Zimbabwean infants

BACKGROUND

Child stunting remains a poorly understood, prevalent public health problem. Environmental enteric dysfunction (EED) is hypothesized to be an important underlying cause.

OBJECTIVES

Within a subgroup of 1169 children enrolled in the SHINE (Sanitation Hygiene Infant Nutrition Efficacy) trial in rural Zimbabwe, followed longitudinally from birth to 18 mo of age, we evaluated associations between the concentration of 11 EED biomarkers and linear growth velocity.

METHODS

At infant ages 1, 3, 6, 12, and 18 mo, nurses measured child length and collected stool and blood; the lactulose-mannitol urine test was also conducted at all visits except at 1 mo. Stool neopterin, α-1 antitrypsin, myeloperoxidase, and regenerating gene 1β protein; urinary lactulose and mannitol; and plasma kynurenine, tryptophan, C-reactive protein, insulin-like growth factor-1 (IGF-1), soluble CD14, intestinal fatty acid binding protein, and citrulline were measured. We analyzed the change in relative [∆ length-for-age z score (LAZ)/mo] and absolute (∆ length/mo) growth velocity during 4 age intervals (1-3 mo; 3-6 mo; 6-12 mo; and 12-18 mo) per SD increase in biomarker concentration at the start of each age interval.

RESULTS

In fully adjusted models, we observed only 3 small, statistically significant associations: kynurenine:tryptophan ratio at 12 mo was associated with decreased mean LAZ velocity during the 12-18 mo interval (-0.015 LAZ/mo; 95% CI: -0.029, -0.001 LAZ/mo); mannitol excretion at 6 mo was associated with increased LAZ velocity during the 6-12 mo interval (0.013 LAZ/mo; 95% CI: 0.001, 0.025 LAZ/mo), and plasma IGF-1 at 1 mo was associated with increased LAZ velocity during the 1-3 mo interval (0.118 LAZ/mo; 95% CI: 0.024, 0.211 LAZ/mo). Results for absolute growth velocity were similar, except IGF-1 was also associated with growth during the 12-18 mo interval. We found no other associations between any EED biomarker and linear growth velocity.

CONCLUSIONS

None of 11 biomarkers of EED were consistently associated with linear growth among Zimbabwean children.This trial was registered at clinicaltrials.gov as NCT01824940.

Is breast milk iodine concentration an influential factor in growth- and obesity-related hormones and infants' growth parameters?

Iodine, a key constituent of thyroid hormones, plays an indirect role in prenatal and postnatal growth. This study aimed to investigate whether breast milk iodine concentration (BMIC) is associated with growth- and obesity-related hormones and subsequently the infants' anthropometric measures. In present study conducted in Tehran (Iran), 94 lactating mothers and healthy infants who were exclusively breastfed were included. Concentrations of iodine, insulin-like growth factor-1 (IGF-1), adiponectin (AD) and leptin (LP) were measured in breast milk samples collected during 3- to 5-day postpartum. Anthropometric measures of infants were assessed at 6 months of life, and age- and sex-specific z-score values were calculated using the World Health Organization growth standards. The median (interquartile range) iodine, IGF-1, AD and LP concentrations were 232.5 (157.5-296.0) μg L-1 , 15.7 (11.9-21.1) ng ml-1 , 13.2 (5.1-29.8) mg L-1 and 1.16 (0.86-1.70) ng ml-1 in breast milk, respectively. No significant correlations were found between BMIC and IGF-1, AD and LP concentrations during the first few days postpartum. In adjusted regression model, BMIC was positively associated with weight-for-length z score of infants. In the presence of IGF-1, AD or LP, the coefficients of BMIC for weight-for-length z score of infants were β = .003 (P = .021), β = .002 (P = .028) or β = .003 (P = .013), respectively. No other anthropometric measurements were associated with iodine or growth- and obesity-related hormones in breast milk. Our findings indicate that BMIC is a potential contributor to infants' growth status, independent of IGF-1, AD or LP concentrations in breast milk. The underlying mechanisms remain to be elucidated.

Early life feeding and current dietary patterns are associated with biomarkers of glucose and lipid metabolism in young women from the Nutritionist's Health Study

BACKGROUND/OBJECTIVES

We investigated if breastfeeding duration and current dietary patterns (DP) were associated with glucose and lipid metabolism biomarkers in women from the Nutritionist's Health Study.

SUBJECTS/METHODS

This is a cross-sectional analysis of 200 healthy undergraduates and nutrition graduates aged ≤45 years. Total [<6; ≥6 months] and predominant [<3; ≥3 months] breastfeeding were recalled using questionnaires. Diet were assessed using a food frequency questionnaire. DP obtained by factor analysis by principal component were categorized into tertiles of adherence (T1 = reference). Glucose and lipid biomarkers were categorized into tertiles (T1 + T2 = reference). Logistic regression was applied considering minimal sufficient adjustment recommended by directed acyclic graphs.

RESULTS

Median (interquartile range) age and BMI were 23.0 (20.0; 28.5) years and 22.6 (20.7; 25.4) kg/m², respectively. Mean ± SD values of glucose, LDL-c and HDL-c were 82.0 ± 9.0, 101.1 ± 29.6 and 54.4 ± 12.4 mg/dL, respectively. Women breastfed for <6 months had higher chance of being classified into T3 of insulin (OR = 2.87; 95%CI = 1.28-6.40). Predominant breastfeeding < 3 months was associated with insulin levels (OR = 2.27; 95%CI = 1.02-5.02) and HOMA-IR (OR = 2.36; 95%CI = 1.06-5.26). Breastfeeding was not associated with lipids. The Processed pattern was directly associated with LDL-c (T3: OR 6.08; 95%CI 1.80-20.58; P-trend = 0.004), while the Prudent pattern was inversely associated with LDL-c (T3: OR 0.26; 95%CI 0.08-0.87; P-trend = 0.029) and LDL-c/HDL-c ratio (T3: OR 0.28; 95%CI 0.08-0.97; P-trend = 0.046).

CONCLUSION

Early feeding could be a protective factor against insulin resistance development, while current DP were associated with lipid profile. This evidence indicates that from early life until early adulthood, dietary habits might influence women's cardiometabolic risk profile.

Factors affecting height velocity in normal prepubertal children

PURPOSE

To analyze the effects of clinical and laboratory factors, including insulinlike growth factor (IGF) levels, on the height velocity of normal prepubertal children.

METHODS

Ninety-five healthy prepubertal children (33 boys, 62 girls) were enrolled. The mean chronological age was 6.3±1.4 years, with a height standard deviation score (SDS) of -0.88±0.70. IGF-1, IGF binding protein-3 (IGFBP-3), SDS for anthropometric measurements, and changes in SDS for anthropometric measurements were analyzed for 1 year, and their associations with 1-year height velocity were investigated.

RESULTS

The group of children with a 1-year height velocity of ≥6 cm were chronologically younger than the group with a 1-year height velocity of &lt;6 cm (5.9±1.3 years vs. 6.7±1.3 years, P=0.004), with a lesser increase of SDS for body mass index (BMI) over 1 year (-0.18±0.68 vs. 0.13±0.53, P=0.014). There were no differences between the 2 groups in IGF-1 SDS and IGFBP-3 SDS. Multiple linear regression showed that baseline chronological age (r=0.243, P=0.026) and height SDS (r=0.236, P=0.030) were positively associated with IGF-1 SDS. Binomial logistic regression showed that an older chronologic age at referral (odds ratio [OR], 0.68; 95% confidence interval [CI], 0.47-0.99) and an increase of BMI SDS over 1 year (OR, 0.41; 95% CI, 0.18-0.89) were associated with a decreased growth possibility of an above-average height velocity (≥6 cm/yr).

CONCLUSION

Height velocity of normal prepubertal children is affected by an increase of BMI SDS and chronological age. Prepubertal IGF-1 SDS reflects height SDS at the time of measurement but is not associated with subsequent height velocity.

IGF-I and IGFBP-3 concentrations at 2 years: associations with anthropometry and milk consumption in an Indian cohort

BACKGROUND/OBJECTIVES

To ascertain associations between plasma insulin-like growth factor I (IGF-I), insulin-like growth factor-binding protein 3 (IGFBP-3) and their molar ratio at 2 y with neonatal size, infant growth, body composition at 2 y, and feeding practices in an Indian cohort.

SUBJECTS/METHODS

A cohort of 209 newborns, with 122 followed at 2 y. Anthropometry was conducted at birth and 2 y. IGF-I and IGFBP-3 concentrations were measured in cord blood and at 2 y. Maternal and child diet was assessed by food frequency questionnaires and maternal interviews. Multivariate regression was used to test for associations adjusting for confounding factors.

RESULTS

Mean 2 y plasma IGF-I and IGFBP-3 concentrations and IGF-I/IGFBP-3 were 49.4 ng/ml (95% CI: 44.1, 54.8), 1953.8 ng/ml (CI: 1870.6, 2036.9) ng/ml, and 0.088 (CI: 0.081, 0.095), respectively. IGF-I and IGF-I/IGFBP-3 were positively associated with current length, but not body mass index or adiposity. IGF-I was higher among those with greater change in length since birth. IGF-I concentrations were higher in children who drank the most milk (>500 vs. <250 ml per day: 65.6 vs. 42.8 ng/ml, p < 0.04), received other milk <6 months compared to ≥6 months (56.3 vs. 44.8 ng/ml, p < 0.05), and in those whose mothers consumed milk daily vs. less frequently in late pregnancy (56.4 vs. 42.7 ng/ml, p < 0.01). In multivariate regression, 2 y IGF-I concentration and IGF-I/IGFBP-3 were each positively associated with current length and milk intake. IGFBP-3 was not related to anthropometry or milk intake.

CONCLUSIONS

Plasma IGF-I concentrations and IGF-I/IGFBP-3 at 2 y are positively associated with length at 2 y and current milk intake.

Childhood growth in boys with congenital hypogonadotropic hypogonadism

BACKGROUND

We describe childhood growth patterns in a series of well-characterized patients with congenital hypogonadotropic hypogonadism (CHH) with special emphasis on genotype-phenotype correlation.

METHODS

We retrospectively evaluated the growth charts of 36 males with CHH (27 from Finland and 9 from Denmark). Fifteen patients (42%) had representative growth measurements during the first year of life. Genetically verified diagnosis of CHH was made in 15 (42%) patients (KAL1, FGFR1, GNRHR, or PROK2).

RESULTS

We found a deceleration of growth rate during early childhood. The mean (SD) length standard deviation score (SDS) at birth (0.2 (1.6) SDS) decreased significantly during the first 3 (to -0.9 (1.2) SDS) and 6 mo of life (to -0.7 (1.3) SDS). At the average age of 3 y, mean height SDS (-0.2 (1.3) SDS) did not differ from mid-parental target height (MPH). Mean height SDS reached its nadir (-1.7 (1.4) SDS) at an average age of 15.8 (0.8) years reflecting pubertal failure. Final heights did not differ from MPH. No clear genotype-growth associations emerged.

CONCLUSION

Moderate postnatal length deflection is a novel feature of CHH and may reflect early androgen deficiency. Childhood growth patterns are not of clinical value in targeting molecular genetic diagnosis of CHH.