Electronic Theses and Dissertations

Identifier

2519

Date

2015

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Social and Behavioral Sciences

Committee Chair

Kenneth Daniel Ward

Committee Member

Satish Kedia

Committee Member

George Relyea

Committee Member

Latrice Pichon

Abstract

Maximizing bone mass during growth is important to prevent osteoporosis later in life. Swimming competitively at elite levels during growth does not offer an osteogenic advantage. Swimmers have lower bone mass than athletes who engage in high-impact activities and have similar or lower bone mass than sedentary individuals. Amateur swimmers, who train less intensely than their elite counterparts, may also be at risk of training-related bone mass deficits, but their bone accrual has not been characterized. This dissertation examines determinants of bone accrual over a two-year period in a cohort of 234 Caucasian of 8- to 18-year-old amateur swimmers and non-athletic controls. It was hypothesized that: (1) at baseline, amateur swimmers, compared to non-athletic controls, will have lower dietary intake of several nutrients related to bone accrual, including calcium and vitamin D; (2) at baseline, amateur swimmers, compared to non-athletic controls, will have lower total body and hip bone mineral content (BMC) when adjusting for confounders of bone mass including sex, age, pubertal status, lean mass, calcium intake, and high-impact activity; and (3) over a two-year follow-up period, bone mass accrual at total body and hip will be lower in amateur swimmers than in non-athletic controls, and this effect will remain significant after adjusting for known confounders of bone mass. The main findings are that (1) nutritional profiles of amateur swimmers and of non-athletes have inadequate intakes of calcium and vitamin D; (2) after taking into consideration several known confounders of bone mass, amateur swimmers have 4.2% lower total body BMC (p = 0.020) and similar hip BMC compared to non-athletes; and (3) amateur swimmers and non-athletes increased their total body BMC (+4%, p < 0.001) and hip BMC (+1%; p = 0.014) over a 24-month period, and rates of bone accrual were similar between groups. These results indicate that amateur swimming does not offer an osteogenic advantage but does not appear to have a detrimental effect on bone accrual. Efforts are needed to ensure that the large population of amateur youth swimmers receives adequate nutritional support and supplemental weight-bearing activity to optimize bone accrual.

Comments

Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.

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