The SENECA study: potentials and problems in relating diet to survival over 10 years Wija A van Staveren*, Lisette CPMG de Groot and Annemien Haveman-Nies Wageningen University, Department of Agrotechnology and Food Sciences, Division of Human Nutrition and Epidemiology, PO Box 8129, 6700 EV Wageningen, The Netherlands Abstract 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. Keywords Modified dietary history Validity Mediterranean diet score Predictive value and survival In 1988, a European multi-centre study named SENECA (Survey in Europe on Nutrition and the Elderly; a Concerted Action) was initiated in people born between 1913 and 1918. Nine of the original 19 towns participating in 12 European countries decided to continue the longitudinal study by conducting a second survey in 1993 and a finale in 1999. The aim of SENECA’s finale was to identify dietary and lifestyle factors important for survival and the maintenance of health of SENECA participants since 1988. In nutritional epidemiology, longitudinal studies are expected to be easier and more fruitful in older adults for several reasons. One reason, amongst others, is that people tend to have fairly definite likes and dislikes so that their diet is likely to be more uniform (and may therefore be more easily characterised) with ageing than that of younger persons. Nutritional deficiency is more common at older ages than at other periods in life, yet many elderly people eat well. The dietary variation between individuals is therefore expected to be large in comparison with the variations within individuals. Furthermore, due to increased morbidity and mortality, endpoints in the older category will occur per person year of follow-up more often than at younger ages 1 . However, it is well known that there are also problems in surveying older people 2 . Fading memory is a problem in older adults for reporting on food consumption patterns. Physical disabilities may require special equip- ment, for instance in recording dietary intake. A high proportion of non-responders and dropouts in the course of the study is often observed, which may lead to selectivity. Co-morbidity makes it difficult to diagnose diseases and to distinguish relationships between diet and disease from relationships between diet and ageing 3 . In this paper, the experience gained from the SENECA study is used to illustrate the problems related to dietary assessment in different stages of longitudinal research. Evaluation of the applied method at baseline and follow- up is discussed and the predictive value of the observed intakes for survival examined. q The Authors 2002 *Corresponding author: Email wya.vanstaveren@staff.nutepi.wau.nl. Public Health Nutrition: 5(6A), 901–905 DOI: 10.1079/PHN2002376