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In Reply We thank Mullie and Autier for their correspondence. Regarding adjustment for body mass index (BMI), we disagree with the assertion that adiposity is not part of the causal pathway relating dietary patterns to mortality. In our article,1 Table 2 suggests an association of dietary pattern with BMI. Analysis of covariance analysis demonstrates this to be significant (P < .001) after adjustment for age, sex, race, exercise, and energy intake. Dietary pattern may plausibly affect BMI causally, the association persists after adjustment, and reverse causation seems unlikely. It is generally believed that adiposity causally contributes to mortality. Thus, a potential causal pathway from dietary pattern to mortality with BMI as an intermediate is suggested. Adjustment for such a potential intermediate would remove part of the total “effect” of dietary patterns on mortality. Nevertheless, we reported results for a sensitivity analysis in which BMI was a covariate. This had only modest effects, which were described in our article.1 The odds ratio for all-cause mortality for men and women combined for all vegetarians vs nonvegetarians changed from 0.88 (95% CI, 0.80-0.97) to 0.90 (95% CI, 0.82-0.98) when BMI was included.1
Orlich MJ, Fraser GE. Lack of Adjustment for Body Mass Index—Reply. JAMA Intern Med. 2014;174(1):169. doi:10.1001/jamainternmed.2013.11169