Higher dietary omega-3 polyunsaturated fatty acid intake is associated with reduced all-cause mortality in cancer survivors: A prospective cohort study.

Despite advances in cancer treatment, survivors continue to face elevated all-cause mortality, and the relationship between omega-3 polyunsaturated fatty acids (PUFAs) and mortality in this population remains uncertain. We hypothesized that higher dietary omega-3 PUFA intake is associated with reduced all-cause mortality in cancer survivors. Using data from 4836 adults with self-reported cancer in NHANES (1999-2018), we evaluated dietary intake of omega-3 PUFAs based on 24-hour recalls and categorized it into quartiles. During a median follow-up of 81 months, 1776 deaths occurred. After adjusting for confounders, multivariable Cox proportional hazards regression revealed that each additional gram per day of omega-3 PUFA intake was associated with a 6% reduction in mortality risk (HR: 0.94, 95% CI: 0.89-0.99). When omega-3 PUFA intake was analyzed as a categorical variable, participants in the highest quartile (Q4) had a 24% lower mortality risk compared with those in the lowest quartile (Q1) (HR: 0.76, 95% CI: 0.65-0.90; P for trend < .01).Restricted cubic spline analysis indicated a linear dose-response relationship (P for nonlinearity = .255). In subgroup analyses, body mass index modified this association (interaction P = .031), with significant inverse associations observed among overweight and obese individuals (HR: 0.91, 95% CI: 0.86-0.98) but not among those with normal weight. These findings were robust in sensitivity analyses. In conclusion, higher dietary omega-3 PUFA intake was associated with reduced all-cause mortality in cancer survivors, with stronger associations observed among overweight and obese individuals.