Diet and sedentary behaviour in relation to mortality in US adults with a cardiovascular condition: results from the National Health and Nutrition Examination Survey linked to the US mortality registry.

CVD is the most common chronic condition and the highest cause of mortality in the USA. The aim of the present work was to investigate diet and sedentary behaviour in relation to mortality in US CVD survivors. The National Health and Nutrition Examination Surveys conducted between 1999 and 2014 linked to the US mortality registry updated to 2015 were investigated. Multivariate adjusted Cox regression was used to derive mortality hazards in relation to sedentary behaviour and nutrient intake. A multiplicative and additive interaction analysis was conducted to evaluate how sedentariness and diet influence mortality in US CVD survivors. A sample of 2473 participants followed for a median period of 5·6 years resulted in 761 deaths, and 199 deaths were due to CVD. A monotone increasing relationship between time spent in sedentary activities and mortality risk was observed for all-cause and CVD mortality (hazard ratio (HR) = 1·20, 95 % CI 1·09, 1·31 and HR = 1·19, 95 % CI 1·00, 1·67, respectively). Inverse mortality risks in the range of 22-34 % were observed when comparing the highest with the lowest tertile of dietary fibre, vitamin A, carotene, riboflavin and vitamin C. Sedentariness below 360 min/d and dietary fibre and vitamin intake above the median interact on an additive scale influencing positively all-cause and CVD mortality risk. Reduced sedentariness in combination with a varied diet rich in dietary fibre and vitamins appears to be a useful strategy to reduce all-cause and CVD mortality in US CVD survivors.