Electronic Theses and Dissertations

Identifier

6660

Date

2020

Date of Award

12-1-2020

Document Type

Thesis

Degree Name

Master of Public Health

Major

Public Health

Concentration

Epidemiology

Committee Chair

Wilfried Karmaus

Committee Member

Hongmei Zhang

Committee Member

Yu Jiang

Abstract

Epigenetic markers have been suggested as mediators of early-life nutrition to future health. Prior studies focused on breastfeeding effects on DNA methylation (DNAm), ignoring other feeding modes. In this analysis of the Isle of Wight birth cohort, feeding modes were categorized as exclusive breastfeeding (EBF), exclusive formula feeding (EFF), and mixed feeding based on whether the respective feeding mode lasted for at least 3 months. In addition, in the past, infant feeding modes were assessed using one time point DNAm in childhood, not changes of DNAm. In this paper, methylation differences (Delta DNAm) were calculated by subtracting residual methylation values (adjusting for cell types and season of blood collection at both ages) at birth from age 10 years. These deltas were estimated for all methylation sites where cytosine was followed by guanines (CpG sites). Then we performed an epigenome-wide association study contrasting EBF, EFF, and mixed feeding with delta DNAm that represents changes in DNAm from birth to 10 years. A total of 87 CpGs (EBF: 27 CpGs, EFF: 48 CpGs, mixed: 12 CpGs) were identified using separate linear regression models adjusting for confounders and multiple testing. Interestingly, the sum of all changes in methylation from birth to age 10 years was significantly lower in the EFF group. Correspondingly, the number of CpG sites with a methylation decline was 4.7% higher. Lower methylation related to exclusive formula feeding and its adverse potential for the child’s development needs future research to reduce adverse health effects.

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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