Diet and sedentary behaviour in relation to cancer survival. A report from the national health and nutrition examination survey linked to the U.S. mortality registry

Cancer is the second most common chronic disease and cause of death in the United States. Our aim was to evaluate the associations of sedentary behavior and nutrient intakes with total and cancer-specific mortality among US cancer survivors. Data from 2371 cancer survivors collected by the US National Health and Nutrition Examination Survey between 1999 and 2014 were linked to the US mortality registry. Multivariable adjusted Cox proportional hazard models were used to estimate the hazard ratios (HR) and 95% confidence intervals (CI) for all-cause and cancer-specific mortality associated with sedentary time and nutrient intakes. The interaction between time spent on sedentary activities and nutrient intake was evaluated on additive and multiplicative scales. During a median observational period of 5.7 years, 532 total deaths occurred among cancer survivors, of which 180 were cancer-specific. A monotonic increasing linear relationship between time spent sitting and all-cause mortality was observed (HR = 1.15, 95% CI = 1.03, 1.28 per one standard deviation increment). The highest versus the lowest tertiles of intakes of dietary fiber, carotene, niacin, thiamine, riboflavin, vitamin B6, vitamin B12, and vitamin C were inversely associated with all-cause and cancer-specific mortality (HRs = 0.48 to 0.75). The inverse associations with all-cause mortality were more pronounced for combinations of low sedentary behaviour and high intakes of dietary fiber, carotenoids, vitamin B12, and vitamin C. Our findings support recommendations for cancer survivors to reduce time spent sedentary and to follow a balanced diet with adequate intakes of dietary fiber and micronutrients.