Date of Award

January 2026

Document Type

Thesis

Degree Name

Master of Public Health (MPH)

Department

School of Public Health

First Advisor

Leah M. Ferrucci

Second Advisor

Melinda L. Irwin

Abstract

Background: Lifestyle interventions targeting diet and physical activity improve weight and health outcomes among breast cancer survivors, but their impact on psychosocial factors such as self-esteem is underexplored. Additionally, it is unclear whether baseline self-esteem influences weight loss outcomes or modifies effectiveness of these lifestyle interventions. Methods: Breast cancer survivors with a BMI ≥ 25 kg/m2 were randomized into either a 6-month dietary and physical activity lifestyle intervention (N=93) or usual care (N=58) in the Lifestyle, Exercise and Nutrition (LEAN) study (N=151) to evaluate impacts on weight loss. Self-esteem was assessed at baseline and 6 months using the Rosenberg Self-Esteem Scale. Linear mixed models were used to evaluate changes in self-esteem, assess whether baseline self-esteem predicted weight change, and to test for effect modification by self-esteem of the interventions’ effect on weight loss. Results: The intervention was associated with a modest improvement in self-esteem compared to usual care (mean difference: 1.2; 95% CI: 0.0, 2.4; P=0.05). There was some evidence that participants with baseline low/normal self-esteem had greater increases in self-esteem during the 6-month intervention than those with high baseline self-esteem. Baseline self-esteem was not a significant predictor of weight change within the intervention group (P=0.88). There was no statistically significant interaction between baseline self-esteem and weight loss (P=0.58). Conclusions: A 6-month lifestyle weight loss intervention may modestly improve self-esteem among breast cancer survivors, particularly among those with lower baseline levels. Baseline self-esteem did not significantly influence weight loss outcomes, suggesting that interventions like this can be broadly effective regardless of initial psychosocial status. Improvement in self-esteem may represent an additional benefit for lifestyle-based weight loss programs for women with breast cancer.

Comments

This thesis is restricted to Yale network users only. It will be made publicly available on 09/16/2027

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