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Objective: The objective of this study was to estimate the effects of trimester‐specific gestational weight gain (GWG) on small and large (compared with appropriate) for gestational age (i.e., SGA, LGA, and AGA) by prepregnancy BMI classifications. Methods: We conducted a cohort study of pregnancies in a national network of community health care organizations, stratifying by prepregnancy BMI (n = 20,676 with normal weight; 19,156 with overweight; 11,647 with obesity class I; 5124 with obesity class II; and 3197 with obesity class III). SGA and LGA (vs. AGA) were modeled as a function of trimester 1, 2, or 3 GWG rate, previous trimester(s) GWG rate, and maternal characteristics using modified Poisson regression. Results: GWG rates ranged from weight loss to substantial gains. GWG‐LGA associations were strongest in trimester 1 (risk ratio [RR] range for 10th vs. 50th percentile GWG, across BMI categories: 0.60–0.73). GWG‐SGA associations were strongest in lower BMI categories and in trimester 2; RRs were 1.62, 1.40, and 1.17 for prepregnancy normal weight, obesity class I, and obesity class III, respectively, with curvilinear associations for class II and III. Conclusions: Among people with prepregnancy obesity class II or III, GWG rate is associated with higher LGA risk in a dose‐dependent manner, including understudied ranges of weight loss, but with weak associations with SGA. [ABSTRACT FROM AUTHOR]

Introduction Adverse prenatal development is a contributor to obesity susceptibility in children. Dietary behavior is one mechanism through which adverse prenatal development may promote obesity, but evidence for the role of prenatal overnutrition in dietary intake in young children is scant. Methods We used data from the National Health and Nutrition Examination Survey 2009-2014. Our study sample included 1782 U.S. children 2-5 years old with available birth weight and two 24-h dietary recalls. We used linear and Poisson regression to examine the association of birth weight (LBW 4100 g) and 2-day average intake of dietary variables. We tested interactions between birthweight and breastfeeding (breastfed > 5 months vs. not breastfed or breastfed 0-5 months), and report breastfeeding-specific results. Results In multivariable regression analysis, in boys, LBW was associated with 2.4 (95% CI - 4.3, - 0.5) lower percent of kcal from solid fat; lower sugar intake, marginally lower saturated and total fat intake, and 0.6 cup (95% CI 0.1, 1.0) greater vegetable consumption; HBW was marginally associated with lower fat. Birth weight was unrelated to diet in girls. Breastfeeding modified associations between birth weight and dietary intake, but the direction of modification was mixed. Discussion Our findings do not support the hypothesis that LBW or HBW are associated with adverse diet consumption in preschool age U.S. children. Improved understanding of the role of early life development of dietary behavior requires further research on the development of appetitive traits and the role of the family and preschool food environments., Author(s): Kacey Potis [sup.1] , Emily H. Youngers [sup.1] , Thomas K. Tandy [sup.1] , Erin Takemoto [sup.1] , Janne Boone-Heinonen [sup.1] Author Affiliations: (1) grid.5288.7, 0000 0000 9758 5690, [...]

Abstract Background Recent studies suggest that neighborhood fast food restaurant availability is related to greater obesity, yet few studies have investigated whether neighborhood fast food restaurant availability promotes fast food consumption. Our aim was to estimate the effect of neighborhood fast food availability on frequency of fast food consumption in a national sample of young adults, a population at high risk for obesity. Methods We used national data from U.S. young adults enrolled in wave III (2001-02; ages 18-28) of the National Longitudinal Study of Adolescent Health (n = 13,150). Urbanicity-stratified multivariate negative binomial regression models were used to examine cross-sectional associations between neighborhood fast food availability and individual-level self-reported fast food consumption frequency, controlling for individual and neighborhood characteristics. Results In adjusted analysis, fast food availability was not associated with weekly frequency of fast food consumption in non-urban or low- or high-density urban areas. Conclusions Policies aiming to reduce neighborhood availability as a means to reduce fast food consumption among young adults may be unsuccessful. Consideration of fast food outlets near school or workplace locations, factors specific to more or less urban settings, and the role of individual lifestyle attitudes and preferences are needed in future research.

Abstract Background Built environment research is dominated by cross-sectional designs, which are particularly vulnerable to residential self-selection bias resulting from health-related attitudes, neighborhood preferences, or other unmeasured characteristics related to both neighborhood choice and health-related outcomes. Methods We used cohort data from the National Longitudinal Study of Adolescent Health (United States; Wave I, 1994-95; Wave III, 2001-02; n = 12,701) and a time-varying geographic information system. Longitudinal relationships between moderate to vigorous physical activity (MVPA) bouts and built and socioeconomic environment measures (landcover diversity, pay and public physical activity facilities per 10,000 population, street connectivity, median household income, and crime rate) from adolescence to young adulthood were estimated using random effects models (biased by unmeasured confounders) and fixed effects models (within-person estimator, which adjusts for unmeasured confounders that are stable over time). Results Random effects models yielded null associations except for negative crime-MVPA associations [coefficient (95% CI): -0.056 (-0.083, -0.029) in males, -0.061 (-0.090, -0.033) in females]. After controlling for measured and time invariant unmeasured characteristics using within-person estimators, MVPA was higher with greater physical activity pay facilities in males [coefficient (95% CI): 0.024 (0.006, 0.042)], and lower with higher crime rates in males [coefficient (95% CI): -0.107 (-0.140, -0.075)] and females [coefficient (95% CI): -0.046 (-0.083, -0.009)]. Other associations were null or in the counter-intuitive direction. Conclusions Comparison of within-person estimates to estimates unadjusted for unmeasured characteristics suggest that residential self-selection can bias associations toward the null, as opposed to its typical characterization as a positive confounder. Differential environment-MVPA associations by residential relocation suggest that studies examining changes following residential relocation may be vulnerable to selection bias. The authors discuss complexities of adjusting for residential self-selection and residential relocation, particularly during the adolescent to young adult transition.

Abstract Background Inter-relationships among built and socioeconomic environmental characteristics may result in confounding of associations between environment exposure measures and health behaviors or outcomes, but traditional multivariate adjustment can be inappropriate due to collinearity. Methods We used principal factor analysis to describe inter-relationships between a large set of Geographic Information System-derived built and socioeconomic environment measures for adolescents in the National Longitudinal Study of Adolescent Health (Wave I, 1995-96, n = 17,294). Using resulting factors in sex-stratified multivariate negative binomial regression models, we tested for confounding of associations between built and socioeconomic environment characteristics and moderate to vigorous physical activity (MVPA). Finally, we used knowledge gained from factor analysis to construct replicable environmental measures that account for inter-relationships and avoid collinearity. Results Using factor analysis, we identified three built environment constructs [(1) homogenous landscape; 2) development intensity with high pay facility count; 3) development intensity with high public facility count] and two socioeconomic environment constructs [1) advantageous economic environment, 2) disadvantageous social environment]. In regression analysis, confounding of built environment-MVPA associations by socioeconomic environment factors was stronger than among built environment factors. In fully adjusted models, MVPA was negatively associated with the highest (versus lowest) quartile of homogenous land cover in males [exp(coeff) (95% CI): 0.91 (0.86, 0.96)] and intensity (pay facilities) [exp(coeff) (95% CI): 0.92 (0.85, 0.99)] in females. Single proxy measures (Simpson's diversity index, count of pay facilities, count of public facilities, median household income, and crime rate) representing each environmental construct replicated associations with MVPA. Conclusions Environmental characteristics are inter-related. Both built and SES environments should be incorporated into analysis in order to minimize confounding. Single environmental measures may be useful proxies for environmental constructs in longitudinal analysis and replication in external populations, but more research is needed to better understand mechanisms of action, and ultimately identify policy-relevant environmental determinants of physical activity.