Letters Section Editor: Robert M. Golub, MD, Senior Editor.
In Reply: We agree with Dr Chu that other measures of energy expenditure have been shown to be associated with disease-free survival in colon cancer survivors. However, we believe that BMI alone is not a surrogate marker for the potential biological impact of diet and physical activity. In Dignam et al1 (cited by Chu), only patients with class III obesity (BMI ≥35) experienced an inferior disease-free survival compared with normal weight patients. The hazard ratio for very obese patients was 1.28 (95% confidence interval, 1.04-1.57),1 weaker than the association we found for patients with the highest level of a Western pattern diet (hazard ratio, 3.25; 95% confidence interval, 2.04-5.19). In our study, we adjusted for BMI in all multivariate analyses, and this did not attenuate the relationship. Furthermore, as shown in Table 6 of our article, stratification by BMI (≤25 vs >25) showed a similar association for underweight/normal weight individuals and overweight/obese individuals. We are currently in the process of analyzing BMI by cancer state and node status, and intend to publish that information when it is completed.
Meyerhardt J, Fuchs C. Cancer Recurrence and Survival Associated With Dietary Patterns in Stage III Colon Cancer—Reply. JAMA. 2007;298(19):2263. doi:10.1001/jama.298.19.2263-b