Association Between Awareness of Dietary Intake Restriction at Two Time Points and Mortality Outcomes: A Cohort Study in Japan

Our previous study identified a modest association between awareness of dietary intake restriction and all-cause mortality. However, whether repeated awareness is associated with all-cause, cardiovascular disease (CVD), and cancer mortality remained unclear. We analyzed 14,060 participants from the Japan Multi-Institutional Collaborative Cohort Study. Participants reporting energy or fat intake restriction at two points in time, approximately 5 years apart, were classified as having both-survey energy or fat awareness, respectively. Multivariable and inverse probability-weighted (IPW) Cox models estimated hazard ratios (HRs) and 95% confidence intervals (CIs). Over approximately 7 years, 374 deaths occurred. In the IPW model (Model 2), both-survey energy awareness was associated with lower all-cause mortality (HR, 0.76; 95% CI, 0.59-0.97) and CVD mortality (0.48; 0.24-0.97), although the latter was not significant in Model 1; the cancer association was significant in Model 1 but not in Model 2. It should be noted, however, that the number of CVD deaths was extremely low (n = 63) and that, of these, only 10 occurred among individuals with both-survey energy awareness. Both-survey fat awareness was not associated with mortality. Exploratory subgroup analyses suggested inverse awareness–mortality associations. Overall, both-survey energy awareness was inversely associated with all-cause mortality, but cause-specific findings require caution.