Objective: To validate an eighty-nine-item semi-quantitative FFQ for measurement of nutrient intakes in elderly women. Design: FFQ and 3 d food records were filled in by women participating in the Kuopio Fracture Prevention Study (OSTPRE-FPS). Data on intakes of energy, fat, protein, carbohydrate, fibre, Ca, Fe, P, K, Mg, folic acid, vitamin B 12 , vitamin C, vitamin D and vitamin K from ninety-nine women were available to assess the agreement of the two methods. Validity was assessed using correlation coefficients, cross-classification into quintile categories and Bland-Altman plots. Nutrients relevant to bone health were assessed. Setting: OSTPRE-FPS in Finland. Subjects: Elderly women with a mean age 71?3 years. Results: The FFQ overestimated energy and nutrient intakes as compared with food records by 30-50 %. The highest correlation coefficients of the energyadjusted nutrient intakes between the methods were observed for fibre (0?60), Mg (0?56) and folic acid (0?49) and the lowest for protein and vitamin D (both 0?19). The cross-classification of energy-adjusted nutrient intakes showed that on average 68 % of the participants (range 62-78 %) were classified into the same or an adjacent quintile category. Conclusions: The validity of energy and nutrient intakes measured with the FFQ was moderate as compared with 3 d food records in elderly women. The FFQ is a useful tool for the nutrient assessment of elderly women in epidemiological research.
Keywords
FFQ Food record Validity Women ElderlyFew studies have estimated the use and validity of FFQ in nutrient intake estimation in elderly populations (1)(2)(3) . However, determining nutrient intakes is critical in examining the effect of nutrition on health and disease. The FFQ is a useful tool to estimate long-term habitual dietary intake, can be self-administered and is relatively inexpensive. However, an FFQ should be tested in the specified population group before use (4) . Food records are a suitable reference method for assessing the validity of an FFQ because the errors associated with the two methods are independent (5) .The present study examined the nutrient intakes measured in the Kuopio Fracture Prevention Study (OSTPRE-FPS). Therefore, especially the nutrients related to bone health were of interest in the validation. Our aim was to develop a semi-quantitative FFQ for elderly women and to evaluate the relative validity of nutrient intakes estimated by the FFQ as compared with 3 d food records.
Experimental methods
ParticipantsParticipants were recruited from the OSTPRE-FPS (6) , which aims to examine the effect of Ca and vitamin D supplements on falls and fractures in women aged over 65 years during a 3-year intervention. The total number of women in the study was 3432, of whom 750 were randomly selected for a subsample participating in detailed examinations including measurement of bone mineral density and dietary records and FFQ. Dietary data used in the present study were collected at study year 3 (between