Validity of retrospective diet history: Assessing recall of midlife diet using food frequency questionnaire in later life

Abstract

Objectives Limited information exists on the validity of dietary information given by elderly people on their past diet. Here we test the relative validity of a food frequency questionnaire asking older persons about their midlife diet. Design Retrospective food intake of 56–72-year-old subjects was estimated using a food frequency questionnaire designed for the AGES-Reykjavik Study (AGES-FFQ), an epidemiological study of older individuals. Results were compared with detailed dietary data gathered from the same individuals 18–19 years previously, i.e., in midlife, as part of a national cohort. Spearman correlation and cross-classifications were used to assess the ability of the AGES-FFQ to rank subjects according to their intake. Setting Nationwide, Iceland. Participants Subjects, born 1937–1952 (n=174), who participated in the 1990 Icelandic National Dietary Survey. Measurements Dietary intake, estimated by the AGES-FFQ (2008–2009), and dietary history obtained from the 1990 Icelandic National Dietary Survey as a reference method. Results The strongest correlation between the AGES-FFQ and the reference method was found for cod liver oil, r=0.53, p<0.001 and r=0.56, p<0.001, for men and women, respectively. For men the corresponding correlation coefficient for milk and dairy products was r=0.43, p<0.001. The correlation coefficients were lower but within a reasonably acceptable range (r=0.26–0.40) for meat, fish and potatoes for both genders, as well as fresh fruits and milk/dairy products for women and whole-wheat bread, oatmeal/muesli and blood/liver-sausage for men. No correlation was found between the AGES-FFQ and the dietary history for rye bread and vegetable consumption. Subjects were categorized into five groups according to level of consumption by the two methods. Cross-classification showed that 16–59% were classified into same group and 43–91% into same or adjacent group, 0–14% were grossly misclassified into opposite groups. Conclusion The AGES-FFQ on midlife diet was found suitable to rank individuals by their intake of several important food groups.

Milk consumption throughout life and bone mineral content and density in elderly men and women

“…Foods and food groups were selected for the questionnaire on the basis of their contribution to the absolute intake of elderly Icelanders according to a National Nutrition Survey [24] as well as their unique nutritional qualities and possible connection to the development of various diseases in later life. The questionnaire has been described previously [20, 21]. …”

“…Validity of questions on midlife diet and current diet has been assessed in previous studies, and milk was among the foods that showed the highest validity [20, 21]. Midlife milk intake of 56–72-year-old individuals was estimated retrospectively using the questions on midlife diet in the AGES-FFQ and results compared with detailed dietary data, gathered from the same individuals 18–19 years previously, i.e., in midlife, as a part of a national dietary survey [24].…”

“…Midlife milk intake of 56–72-year-old individuals was estimated retrospectively using the questions on midlife diet in the AGES-FFQ and results compared with detailed dietary data, gathered from the same individuals 18–19 years previously, i.e., in midlife, as a part of a national dietary survey [24]. Correlation using Spearman’s rho was r =0.43, p <0.001 and r =0.29, p =0.003 for men and women, respectively [20]. The validity of current milk intake was assessed among elderly individuals (average age 74 years) by comparing answers of the AGES-FFQ to 3-day weighed food records completed by the same individuals.…”

“…Current consumption of alcohol was converted into grams per week using 14 g of alcohol as a standard drink and then divided into <25, 25–50, and >50 g/week. Information on cod liver oil intake was gathered using the AGES-FFQ [19, 20]. Midlife data on BMI had been collected in the Reykjavik Study [22].…”

Plasma phospholipid fatty acids and fish-oil consumption in relation to osteoporotic fracture risk in older adults: the Age, Gene/Environment Susceptibility Study

“…The FFQ for midlife was validated with dietary data gathered from the same individuals in midlife (Reykjavik Study), and late-life intake was validated against weighed dietary intake. Correlations for fish liver oil ranged from 0.42 to 0.56 (P , 0.001) (20,21). Early-life dietary habits have not yet been validated but are consistent with residency dependent dietary habits (i.e., higher fish consumption in coastal areas) (22).…”