Relationships among attention function, exercise, and body mass index: a comparison between young breast cancer survivors and acquaintance controls.

OBJECTIVE

Although regular physical activity is associated with lower all-cause and disease-specific mortality among breast cancer survivors (BCS), most BCS do not meet its recommended guidelines. Attention function, a domain of cognition, is essential for daily tasks such as exercising, a form of planned physical activity. We tested the hypotheses that lower self-reported attention function in BCS would be associated with less exercise and higher body mass index (BMI) by comparing a group of 505 young BCS (45 years or younger at diagnosis and 3-8 years post-treatment) with 466 acquaintance controls (AC).

METHODS

The groups were compared on self-reported physical and psychological outcomes. Mplus software was used to perform confirmatory structural equation modeling with a robust maximum likelihood estimator to evaluate hypothesized relationships among variables. The criteria for good model fit were having root mean square error of approximation (RMSEA) < 0.06, comparative fit index (CFI) > 0.95, and standardized root mean square residual (SRMR) < 0.08. Modification indices were used to better fit the model.

RESULTS

The final model demonstrated good fit, with RMSEA = 0.05, CFI = 0.98, and SRMR = 0.03. After controlling for demographics, parameter estimates revealed that, compared with AC, young BCS reported worse attention function (p < 0.001), more depressive symptoms (p < 0.001), and more fatigue (p < 0.001). Controlling for fatigue, depression, and anxiety, better attention function was associated with a greater likelihood of exercise in the past 3 months (p = 0.039), which in turn was associated with a lower BMI (p < 0.001).

CONCLUSIONS

The significant association between attention function and physical activity, if confirmed in a longitudinal study, will provide new targets for interventions aimed at improving physical activity and decreasing BMI among BCS.