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theses

According to nationally representative surveys, since the 1980s, obesity has been on the rise in Mexico, with a current prevalence of over 30 % in adults. Obesity is a serious public health problem as it contributes to type II diabetes, asthma, cancer, osteoporosis, and heart disease. Substantial evidence suggests that the path to obesity is established in early life. According to cohort studies in low- and middle-income countries (LMICs), the risk of chronic disease increases in children who were undernourished or experienced rapid growth post-infancy. However, these cohorts included children born before the recent changes brought about by nutrition transition, so it is unclear if these findings can be generalized to LMIC populations.
The objective of this dissertation is to study the longitudinal relationship between early growth and the development of childhood obesity and body composition in late childhood in children living in Cuernavaca, Mexico. Study participants were a sub-sample of a longitudinal cohort study. The study participants were the offspring of women (n=1094) who participated in the POSGRAD study, a double-blind, randomized, placebo-controlled trial designed to assess the effects of prenatal supplementation with DHA on offspring growth and development (NCT00646360) that was conducted from 2004-2006, and followed up through age 8-10 y. Body composition measurements were obtained using bioelectric impedance in a subsample of 545 children from the POSGRAD cohort at age 8-10y. In this cohort, growth-retarded children had higher body mass index z-scores (BMIZ), fat mass (FM), and lower fat-free mass (FFM) at follow-up in comparison with their non-growth-retarded peers. Using latent class growth analysis, two distinct trajectories of growth for height and weight in both genders were identified. In the first set of analyses, with the outcomes at seven years, we observed that belonging to the high-weight trajectory for both girls and boys was associated with higher odds of being overweight or obese at age seven in comparison with the low-weight trajectory. This association was inverted, however, in the height-growth trajectory analysis, where remaining taller during the first five years of life had a negative relationship on obesity status at follow-up. When using body composition as an outcome at a later follow-up period, we observed three height trajectories for boys and two for girls. The lowest-height trajectory class in boys was associated with increased FM and lower FFM at follow-up and the high-height trajectory class was associated with lower FM and higher FFM in comparison with the intermediate-height trajectory class. No significant association was observed between growth trajectories and body composition in girls. Our research suggests that early adverse growth patterns (rapid weight gain or growth retardation) influence body composition or obesity status later in life. Future research needs to focus on discrete aspects of growth and the development of obesity to better understand how to prevent or reverse the double burden of disease.

ETD_9459

Ph.D.

Includes bibliographical references

by Pamela L. Barrios

doi:10.7282/t3-stvm-m249

ETD doctoral

The author owns the copyright to this work.