Dissertations & Theses (Open Access)

Date of Award

12-2019

Degree Name

Doctor of Public Health (DrPH)

Advisor(s)

Courtney E Byrd-Williams

Second Advisor

Casey P Durand

Third Advisor

Harold Kohl

Abstract

With nearly one-quarter (23%) of U.S. preschool children (ages 3-5 years) having overweight or obesity, supporting healthy growth and development is paramount. Hispanic children have the highest prevalence within this age group (15.6%) and a large projected population growth. Energy expenditure through physical activity is one way to combat excess development of obesity and poor health outcomes. Yet there is limited evidence about the correlates associated with physical activity and health within this population. The three studies of this dissertation examined sociodemographic-, cultural-, and context-related factors related to waking activity patterns and the subsequent impact on health indicators. The overall sample was a majority-minority sample of preschool-aged children, aged 2-5 years, with overweight and obesity participating in the baseline assessment of the Texas Childhood Obesity Research Demonstration (TX CORD). The specific aims were to describe and compare waking activity patterns by individual- (age, sex), family- (language spoken at home, family income) (Paper #1), and context-related (day-type, school) (Paper #2) factors. Paper #3 examined the adiposity, cardiovascular, and quality of life outcomes related to these waking activity behaviors. Studies #1 and #2 used Mann-Whitney U test or Kruskal-Wallis tests, depending on the number of categories, to compare differences in waking activity patterns across the correlates. Paper #1 additionally used logistic regressions to examine the odds of meeting physical activity guidelines by correlate. Paper #2 additionally used Wilcoxon signed-rank tests to determine differences in activity patterns by type of day. Isotemporal substitution modeling examined the hypothetical effect on health when adding and substituting waking activity behaviors (Paper #3). Paper #1 results show 75% of participants met the daily physical activity guideline, with clear sociodemographic and cultural differences. Being male (Δ 23.5 min), non-Hispanic (Δ 22.6 min), speaking primarily English (Δ 19.1 min), and living in a family with a higher income to poverty ratio (Δ 18.6 min) were significantly associated with more moderate to vigorous physical activity (MVPA). Paper #2 found preschool children attending school/ child care had significantly higher light intensity activity (Δ 15.7 min), MVPA (Δ 13.2 min), and TPA (Δ 28.1 min) estimates than children not enrolled. Paper #3 found substituting as little as 15 minutes a day of sedentary, light intensity, or moderate intensity activity with vigorous intensity activity was beneficial in lowering systolic and diastolic blood pressure, body mass index (BMI) z-score, percentage of the 95th percentile, fat mass percent, fat mass index (FMI), waist circumference, and waist to height ratio. This association was particularly important for boys, as girls did not show a significant association with adiposity indicators. The results of this dissertation emphasize the need to utilize an ecological perspective when examining waking physical activity patterns and the impact on health. Promoting vigorous intensity physical activity in this age group can help reduce the burden of poor health. Longitudinal study designs are still needed to determine the impact of these correlates on physical activity and long-term health.

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