BMI, Cancer Risk Behaviors, and Readiness for Dietary Change Among Women Surviving with Breast Cancer

Breast cancer survivors (BCS) are at increased risk of recurrence and poorer outcomes if they are overweight [bod mass index (BMI) = 25-29.9] or obese (BMI = 30+) compared to those with a healthy weight; nutrition counseling is a key component of their secondary prevention and supportive care. The stages of change (SoC) continuum, part of the transtheoretical model (TTM), conceptualizes dietary behavior change as a progression from not yet considering change (Precontemplation) to sustained change (Maintenance). We studied BCS readiness to change diet, along with other cancer risk behaviors, in relationship to BMI.

A secondary data analysis was conducted among N = 936 BCS who contacted a community-based cancer control organization for information and support services during and after cancer treatment. Data (demographics, cancer prevention awareness, BMI, tobacco and alcohol use, physical activity) were collected 30 days later, including BCS dietary SoC.

Among BCS, 37% were ≤=45 years, 18.3% were non-white, 22.3% rated their general health as fair/poor, and 46.9% carried a pathogenic variant in BRCA. The M (SD) BMI was 27.1 (6.4), and 56.1% were overweight/obese. Among the risk behaviors assessed, 27.9% of BCS were current or former tobacco users, 33.5% had consumed 2+ drinks containing alcohol in the past 30 days (16.5% consumed 4+ alcohol drinks in 1 sitting), and 30% were not physically active: a majority were aware of cancer prevention guidelines for alcohol (92.7%), physical activity (95%), and nutrition (92.7%). Regarding TTM's SoC, Maintenance consistently had the largest percentage across all dietary behaviors: avoiding red meat (65.6%) and increasing fiber consumption (63.6) showed the highest maintenance. The Preparation and Action stages varied, with the highest proportion (29.8%) increasing fruit/vegetable consumption. The Precontemplation and Contemplation stages were relatively low for all behaviors (<20%). In bivariate analyses, BCS who were overweight/obese (t = -4.23, df = 728, p<0.001), and engaged in less physical activity (t = 6.8, df = 781, p<0.001), reported less dietary change readiness.

Effective dietary interventions may depend on BCS readiness for change (e.g., raising awareness for those in Precontemplation). The TTM can help tailor behavior change strategies to enhance BCS motivation, especially for overweight/obese and less physically active BCS at greatest risk for recurrence.