Does Residential Setting (urban vs. rural) Moderate the Effects of Physical Exercise and Body Mass Index on Self-Rated Health Among Breast Cancer Survivors?

Background/Purpose: Breast cancer is the most common cancer in the US. More than 3.1 million people in the US are living with breast cancer or have a breast cancer history. Significant rural-urban disparities in health status have been found among cancer survivors. Aiming toward improving treatment outcomes, quality of life and overall survival rates, physical activity guidelines have been issued by the American Cancer Society. Based on diminishing marginal utility theory, marginal utility decreases with increased consumption of services. Considering notable disparities in health resources, breast cancer survivors in rural settings consume fewer health services than urban survivors. Therefore, the authors hypothesize that conducting exercises and lowering body mass index (BMI) will provide greater health benefit to rural survivors through self-rated health (SRH) than their urban counterparts who have additional resources beyond adhering to exercise. This study (1) examines the effect of exercise and BMI on SRH among breast cancer survivors, and (2) explores how rural/urban residential setting moderates this effect.

Methods: This cross-sectional study utilizes 2018 Health Information National Trends Survey (HINTS) data. HINTS provides access to information related to cancer diagnoses and care among US residents. Within the current study, the analytic sample includes only people who had been diagnosed with breast cancer (N=108). SRH, measured on a 5-point Likert scale, was the dependent variable. Time spent exercising per week and BMI were continuous independent variables. Rural/urban residential setting was tested as a moderator. Demographic information (age, gender, and marital status), socioeconomic status (education and income), chronic disease diagnoses and quality of health care were included as covariates. Missing data was minimal (< 10%) and listwise-deletion was employed. Multiple linear regressions were conducted with and without interaction terms (residential setting & exercise time, residential setting & BMI) to predict SRH among breast cancer survivors and test interaction effects of rural versus urban residential settings.

Findings: Roughly 20% (n=19) of breast cancer survivors resided in rural areas. Descriptive statistics showed no differences between urban and rural breast cancer survivors except in marital status, where rural breast cancer survivors were married or partnered at a 21% higher rate than urban survivors (p<.05). The model was first constructed without interaction terms (R²=.30), where quality of health care (β=.247) and chronic disease diagnoses (β=.318) were significant predictors of SRH (p<.05). Exercise time and BMI were not significant. Upon including interaction terms within the model (R²=.36), quality of care and chronic disease diagnoses remained predictive, while the interaction of residential setting and exercise time (β=.345) was also predictive of SRH (p<.05), where 1-unit increase in exercise led to a .155-unit increase in SRH among rural survivors while 1-unit increase led to a .190-unit decrease among urban survivors. The interaction of residential setting and BMI was not significant.

Conclusions: Findings support the hypothesis that rural breast cancer survivors benefit more from exercise than their urban counterparts. These findings suggest that conducting interventions in rural areas to promote physical exercise among breast cancer survivors may be a convenient and efficient way to decrease health disparities.