Yiyi LiFollow

Date of Award

January 2024

Document Type

Thesis

Degree Name

Master of Public Health (MPH)

Department

School of Public Health

First Advisor

Leah M. Ferrucci

Abstract

Introduction: As the number of breast cancer survivors increases, ensuring quality of life during the survivorship period is important. Obesity may induce oxidative stress, which may be relevant mechanistically for adverse health outcomes among breast cancer survivors. Diet, exercise, and weight loss may mitigate oxidative stress, yet few lifestyle trials have investigated if these interventions have impacted oxidative stress. Therefore, we conducted a secondary analysis in a 6-month weight loss randomized controlled trial, the Lifestyle, Exercise, and Nutrition (LEAN) study, among breast cancer survivors with a body mass index (BMI) ≥ 25 kg/m2 to evaluate the effect of the intervention on serum oxidative stress biomarkers.

Methods: Among the 151 women randomized to the LEAN study, 126 participants had paired serum samples in which we evaluated the effect of the weight loss intervention on 6-month changes in three oxidative stress biomarkers (8-hydroxy-2'-deoxyguanosine (8-OHdG), malondialdehyde (MDA), and advanced glycation end products (AGEs)) by study arm via paired t-tests. We also evaluated relationships among 8-OHdG, MDA, AGEs, age, BMI, and dietary antioxidant intake via Pearson correlation coefficients.

Results: There were no significant differences in 6-month changes in 8-OHdG and MDA in either study arm, but AGEs significantly decreased in both arms (intervention = -0.66 ug/mL, p-value = 0.004) (usual care = -1.34 ug/mL, p-value = 0.007). However, there were no significant differences in the 6-month changes in 8-OHdG (p-value = 0.415), MDA (p-value = 0.306), or AGEs (p-value = 0.196) by study arm. At baseline, MDA was positively correlated with 8-OHdG and AGEs, but 8-OHdG and AGEs were not significantly correlated. Six-months changes in all the biomarkers were correlated. There were no significant correlations between either baseline BMI or age and baseline biomarkers or the 6-month changes in biomarkers. The only significant correlation found between the biomarkers and dietary antioxidant intake was a positive correlation between the 6-month changes in MDA and beta-cryptoxanthin (r = 0.199, p-value = 0.031).

Conclusion: Among this population of breast cancer survivors with a BMI ≥ 25 kg/m2, there was no evidence that a lifestyle weight loss intervention affected serum oxidative stress biomarkers. Given limited research on this topic, additional studies are needed to fully characterize if lifestyle interventions can impact oxidative stress among breast cancer survivors with overweight and obesity.

Comments

This thesis is restricted to Yale network users only. It will be made publicly available on 05/07/2026

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