Influence of nutritional intake on 6-year mortality in an Italian elderly population

Many observations agree on the existence, in older ages, of nutritional deficiencies secondary to dietary intake. This study investigated to what extent dietary intake of calories, protein, iron and vitamins influences the 6-year mortality in an elderly population living at home. To prevent the confounding effect of non-dietary factors, such as gender, functional and health status, socio-economic conditions and health risk habits, these variable have also been considered. The dietary intake was calculated comparing the content of nutrients in self-reported, 24-hour diet, with the 1980 Recommended Dietary Allowances (RDA) obtaining a percentage for each nutrient. The percentage difference from the RDA was tested on 6-year mortality using a bivariate regression model. The intake of protein, vitamin A, thiamin, niacin, vitamin B6 and folate was significantly related to mortality: subjects with a lower dietary intake of those nutrients had a higher risk of death. When nutrient intake was tested in a multiple regression model, adjusted for non-dietary potential confounders, only folate was an independent predictor of mortality. This study shows that most of the dietary nutrient's intake is related to socio-economic and physical factors.