Associations of early life growth with health at age 22 years as measured by an allostatic load index: birth to twenty plus cohort
Date
2019
Authors
McGowan, Craig
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Growth in early life is associated with various individual health outcomes in
adulthood, but limited research has been done on associations with a more
comprehensive measure of health. Combining information from multiple biological
systems, the allostatic load score provides such a quantitative measure of overall
physiological health. Using longitudinal data from the Birth to Twenty Plus cohort in
South Africa, an allostatic load score in young adulthood (at age 22 y) was
calculated and associations with birth weight and linear growth and weight gain from
age 0-2 y and 2-5 y were examined, as mediated by trajectories of body mass index
and pubertal development in later childhood and adolescence. Missing measures of
components of the allostatic load measure were addressed using multiple imputation
by chained equations. Association with total allostatic load score were assessed
using Poisson regression, while associations with high allostatic load was assessed
using logistic regression. Differences in total allostatic load score between males and
females were small, though levels of individual biological factors contributing to
allostatic load differed by sex. Increased weight gain from age 2 to 5 y among males
was associated with an increased risk of high allostatic load, but no other early life
measures were associated with allostatic load. Increased adiposity through
childhood and adolescence in females was associated with higher allostatic load in
early adulthood. These results illustrate that patterns of early life growth are not
consistently associated with a higher allostatic load. While more research is needed
to link allostatic load in young adulthood to later health outcomes in settings like
South Africa, these results suggest that increased adiposity during childhood and
adolescence represents a critical factor and potential early sign of later physiological
health risk.
Description
A Dissertation submitted to the Faculty of Health Sciences, University of the
Witwatersrand, in fulfillment of the requirements for the degree of Master of Science.
Johannesburg, 2019