The SENECA study: potentials and problems in relating diet to survival over 10 years.

OBJECTIVE To give an overview of the evaluation of the modified diet history applied in the SENECA study (Survey in Europe on Nutrition and the Elderly; a Concerted Action). DESIGN Nineteen centres in 12 countries participated at baseline. Nine of these SENECA centres conducted a repeat measurement scheme in elderly people born between 1913 and 1918. These longitudinal centres included 100 subjects per sex per site. METHODS The relative validity of the method was tested by comparing results of the modified diet history with results obtained from a weighed record in 82 subjects. In the follow-up we compared changes in energy intake with changes in body weight and calculated the physical activity ratio in all longitudinal centres. In SENECA's finale we examined the predictive value of dietary patterns observed at baseline for survival 10 years later, making use of the original and an adapted Mediterranean Diet Score. RESULTS The modified diet history overestimated intake, compared with the weighed record. However, the physical activity ratio and an in-depth study in a metabolic room indicated that the diet history rather underestimated energy intake. We did not find a relationship between changes in energy intake and changes in body weight, but this could be explained by the fact that most likely we did not measure intake in the dynamic phase of body weight change. Based on the adapted Mediterranean Diet Score, the study results showed a positive relation between a healthy diet and survival. CONCLUSION We conclude that the modified diet history has given sufficiently reliable results for the purposes of the study.