%0 PDF %T Associations of Early-Life Nutritional Exposures, Growth-Promoting Hormones and Fetal and Childhood Growth: Analysis of Mother-Child Pairs in Project Viva. %A Switkowski, Karen. %8 2017-04-14 %R http://localhost/files/1831cw81h %X Abstract: Background: Evidence from animal, epidemiologic, and intervention studies suggests that prenatal and early postnatal nutritional exposures may program growth-regulating hormones, fetal and childhood growth patterns, and ultimately risk of associated chronic diseases in later life. Approaches to understanding and preventing unfavorable growth patterns and chronic disease increasingly emphasize a life-course perspective. Objective: The objective of this dissertation was to explore the role of early-life exposure to dietary protein in programming fetal and childhood growth, including evaluating the role of the insulin-like growth factor (IGF) axis. Methods: We used data from Project Viva, a Boston, MA-based cohort of mother-child pairs. We analyzed energy- and weight-adjusted maternal and child protein intakes assessed by food frequency questionnaire. We used multivariable linear regression models adjusted for covariates to assess the following associations: Aim 1: Maternal 1st- and 2nd-trimester protein intake with offspring length at birth and in infancy (~6mo), early childhood (~3y), and mid-childhood (~7y) (N=1961); Aim 2: Maternal 2nd-trimester protein intake with cord blood IGF-I, IGF-II, IGFBP-3 and insulin levels, including effect modification by child sex and parity (N=938); and Aim 3: Early childhood protein intake with adiposity (BMI z-score, sum of skinfolds and dual X-ray absorptiometry (DXA) fat mass), height and IGF-I levels in mid-childhood (N=1058). Results: Mean 2nd-trimester protein intake was 1.4g/kg/d. Mothers were predominantly white, college-educated, and non-smokers. Aim 1: In adjusted models, each 1-SD (0.36g/kg/d) increment in 2nd-trimester protein intake corresponded to changes of -0.10 (95% CI: -0.18, -0.03) in birth length z-score; -0.03cm/mo (95% CI: -0.05, -0.01) in slope of length growth from birth to <6mo; and -0.09cm/y (95% CI: -0.14, -0.05) in slope of length growth from 6mo to mid-childhood. Aim 2: In adjusted models, each 1-SD (0.35g/kg/d) increment in 2nd-trimester protein intake corresponded to changes of -0.71 (-2.48, 1.05) ng/mL in IGF-I, -12.2 (-19.3, -5.14) ng/mL in IGF-II, -37.2 (-60.7, -13.6) ng/mL in IGFBP-3 and -0.89 (-1.44, -0.34) uU/mL in insulin. Associations with IGF-II were stronger in girls (p for interaction =0.05) and multiparous mothers (p for interaction =0.03), and associations with IGFBP-3 were stronger in multiparous mothers (p for interaction=0.03). Aim 3: Mean early childhood protein intake was 58.2g/d, well above the US recommendation of 13g/d for 1-3y. Early childhood protein intake was not associated with any mid-childhood outcomes. In adjusted models, the βs (95% CIs) for the difference in outcome corresponding to the highest vs. lowest quartile of protein intake were: 0.13 (-0.05, 0.30) BMI z-score; 0.02 (-1.66, 1.69) for SS+TR skinfolds (mm); -0.04 (-0.72, 0.63) for DXA fat mass (kg); 0.05 (-0.11, 0.21) for height z-score; and -5.30 (-29.6, 19.0) for IGF-I (ng/mL). Conclusions: In a cohort of pregnant women with relatively high average protein intake, higher intake was associated with shorter offspring birth length, slower linear growth into mid-childhood, and lower levels of growth-promoting hormones in cord blood. Results suggest that high protein intake during pregnancy does not increase fetal and child growth and may even reduce early length growth, possibly via effects on hormones. Additionally, our results do not support a role for early childhood protein intake in programming later adiposity or height growth in children with high average intake.; Thesis (Ph.D.)--Tufts University, 2017.; Submitted to the Dept. of Nutritional Epidemiology.; Advisor: Paul Jacques.; Committee: Aviva Must, and Emily Oken.; Keywords: Nutrition, and Epidemiology. %[ 2022-10-11 %9 Text %~ Tufts Digital Library %W Institution