Amna Umer

Date of Graduation

2016

Document Type

Dissertation

Degree Type

PhD

College

School of Public Health

Department

Epidemiology

Committee Chair

Christa L Lilly

Committee Co-Chair

Lesley Cottrell

Committee Member

Peter Giacobbi, Jr

Committee Member

Kim Innes

Committee Member

George A Kelley

Abstract

Introduction: Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in the world. West Virginia (WV) has one of the highest prevalence of CVD in the United States. The first two studies examined the association between perinatal risk factors (birth weight (BTW) and breastfeeding) and subsequent childhood and maternal CVD risk factors 11 years post-partum. The purpose of the third study was to conduct a systematic review and meta-analysis to examine the evidence regarding the relationship between childhood obesity and adult CVD risk factors.;Method: We used longitudinally linked data from three cross-sectional datasets in WV for the first (N=19,583) and second study (N=10,457). The outcome variables included blood pressure for children and lipid levels for both mothers and children. The exposures were BTW of the infant (study 1) and reported history of breastfeeding obtained retrospectively when the child was in fifth grade (study 2). Mean differences, correlations, and simple regression analyses were performed to examine the unadjusted associations. Multiple regression analysis was performed adjusting for current body mass index (BMI) and additional covariates. For the third study, the search strategy included (1) electronic searches in multiple databases (PubMed (MEDLINE), Web of Science, and Scopus) on June 5, 2015, and (2) citation tracking (N=4,840 citations). Studies were included if they met the following criteria (1) longitudinal study-design, (2) childhood exposure and adult outcomes collected on the same individual over time, (3) childhood obesity, as defined by the authors, (4) English language articles, (5) studies published by June, 2015, (6) the primary outcome measures included: systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol (TC), high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), non-high-density lipoprotein cholesterol (non-HDL), triglycerides (TG), and (7) outcome not self-reported.;Results: BTW was significantly associated with HDL (b= 0.14mg/dL; 95% CI: 0.11, 0.18), LDL (b = -0.1mg/dL; 95% CI: -0.19, -0.016), non-HDL (b = -0.18mg/dL; 95% CI: -0.28, -0.09), and log-TGs (b=-0.007 (-0.008, -0.005) per 1000 g increase in BTW in the adjusted analyses. There was a positive association between BTW and maternal TC levels, which became non-significant in the adjusted analysis [b= 0.4 mg/dL (95% CI: -0.01, 0.90) per1000 g increase in BTW]. None of the other maternal lipids were significant in the unadjusted or the adjusted analysis. For the second study, there was a significant association between reported history of breastfeeding and child's TGs (beta=-0.04; 95% CI: -0.06, -0.01) when adjusted for the child's current BMI and additional covariates. Maternal lipids were not significantly related to their breastfeeding history. For the third study, a total of 23 studies were included in the systematic review and 21 in the meta-analysis. The findings suggest that childhood obesity is significantly and positively associated with adult SBP (Zr = 0.11; 95% CI: 0.07, 0.14), DBP (Zr = 0.11; 95% CI: 0.07, 0.14), and TG (Zr =0.08; 95% CI: 0.03, 0.13), and inversely associated with adult HDL (Zr =-0.06; 95% CI: -0.10, -0.02). For those studies that adjusted for adult BMI, associations were reversed.;Conclusion: Low BTW was associated with poor lipid levels (LDL, HDL, non-HDL, and TG) and breastfeeding was protective for TGs in fifth grade children independent of their current BMI. As CVD risk factors persist from childhood into adulthood, the small effect sizes observed in the first two studies can have potential unfavorable consequence on lipid levels in later adulthood. The results of the systematic review with meta-analysis suggest that childhood obesity is significantly and positively associated with adult SBP, DBP, and TG and negatively associated with adult HDL. Well-designed, longitudinal studies with improved reporting as well as data analysis that include both unadjusted and adjusted associations for adult adiposity are needed before any definitive conclusions can be made.

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