Background/objectives: Assessing food choice and/or nutrient intake in older people, particularly the oldest old (85 years and over), presents particular challenges. In some cases the respondent may have little or no involvement in food acquisition or preparation, in others, cognitive/memory impairment may restrict the ability to recall intake, or physical limitations may affect the ability to record intake. The assessment may therefore need to involve whoever provides care for the older person, of whom there may be more than one. For these reasons, there is a need for validated methods for dietary assessment in large populations within this age range. The need is particularly acute in view of the secular increase in the numbers of older people and the interest in the role of nutrition in maintaining health and ameliorating age-related decline. This paper describes a comparison of two different methods of dietary assessment within the Newcastle 85+ Study; a UK cohort study of health and ageing in the oldest old.
Methods: Two methods, the food frequency questionnaire (FFQ) (based on broad recall of the previous 12 months intake) and the repeated multiple pass recall (MPR) tool (based on detailed recall of the previous day's intake on two separate occasions), were applied in two different groups of approximately 85 individuals aged 85 years. FFQ data were collected during a pilot study conducted between 2003 and 2004, MPR data were collected in the main Newcastle study in 2006. Relative validity was measured by calculation of the ratio of reported energy intake to estimated basal metabolic rate (EI/BMR) and by comparison with dietary intakes reported for subjects of similar age in the UK National Diet and Nutrition Survey.
Results: EI/BMR ratios for MPR were 1.56 and 1.39 for men and women, respectively, and for FFQ were 2.18 and 2.14. The FFQ was found to overestimate energy and nutrient intake considerably. The MPR gave more realistic estimates of energy and nutrient intakes, and was found to be acceptable for use in this population group. However, use of this tool required greater investigator (nurse) time, extra resources for training and quality assurance and additional time and expertise in data processing.
Conclusions: In the Newcastle 85+ Study, where the overall aims include detailed investigation of diet in relation to many variables describing biological, clinical and psychosocial status, we concluded that MPR was the preferable method, although there remains a need for non-subjective methods for assessing dietary intake, that is, biomarker approaches, which can give a comprehensive and objective assessment of dietary exposure.