Assessing Validity of Short Food Frequency Questionnaire on the Dietary Intake in Elderly Iceland Population

Food Frequency Questionnaires (FFQs) are significant tools used in nutritional epidemiological studies but, most of the FFQs used on the elderly are actually those designed for younger subjects.

Therefore, evaluating the validity of food frequency questionnaire (FFQs) on elderly subjects is quintessential before they are used in studies carried out to assess diet-related disease risks and health outcomes.

Assessing the dietary intake of older individuals has always remained a challenge. This may be due to their fading memory, visual and auditory impairment or impaired cognitive function.

Although short questionnaires are not as informative as long ones they are adequate enough to assess the intake of specific foods and categorize individuals according to selective nutrients.

The AGES-FFQ is a short food frequency questionnaire that has been specially designed for the elderly. AGES- Reykjavik study involving 5,764 elderly participants. AGES stands for Age Gene-Environment Susceptibility and the study evaluates risk factors, genetic susceptibility, gene/environment interaction (particularly diet) and the influence these factors have on disease and disability in the aged. The AGES-FFQ has queries regarding a person's diet during early life, midlife and present diet.

The aim of the present study is to assess the validity and ability of the AGES-FFQ to categorize individuals according to their intake of selective foods and food groups.

The subjects were elderly people 65 years and older of which 58.6% were female. Exclusion criteria involved sub-standard cognitive function, certain skeletal diseases, uncontrolled CHD, administration of testosterone or certain other specific drugs known to influence muscle mass.

The participants were required to answer the AGES-FFQ and then fill out a 3-day weighed food form within two weeks time. They also answered questions regarding their exercise regime, quality of life with special emphasis on health and also regarding their supplement intake such as vitamins, herbal medicine or other drugs.

The AGES-FFQ was then compared with the reference method (weighed food record). Weighed food records are considered the "gold standard" in validating food questionnaires and the elderly are quite adept at maintaining these records.

In the case of mena correlation [greater than or equal to] 0.4 was found for potatoes, oatmeal/muesli, fresh fruits, cakes/cookies, dairy products, milk, candies, pure fruit juice, coffee, tea, cod liver oil and sugar in coffee/tea (r = 0.40-0.71). A lower, but acceptable, correlation was discovered in the case of raw vegetables (r = 0.33).

In the case of women, the highest correlation was found for the intake of rye bread, oatmeal/muesli, candy, raw vegetables, dairy products, milk, cod liver oil, pure fruit juice, coffee and tea (r = 0.40-0.61) while an acceptable correlation was found for fish topping/salad, blood/liver sausage, fresh fruits, whole-wheat bread, and sugar in coffee/tea (r = 0.28-0.37).

The questions regarding meat/fish meals, cooked vegetables and soft drinks did not show a significant correlation to the reference method. However these questions must not be discarded as irrelevant and must be further probed.

Most of the questions that feature in the AGES-FFQ had an acceptable correlation and may be employed to rank elderly individuals in accordance to their intake of significant foods/food groups and their impact on health. However, it is not useful in assessing total food intake, nutrients or energy.

Reference:

1. Assessing validity of a short food frequency questionnaire on present dietary intake of elderly Icelanders; Tinna Eysteindottir et al;BMC Nutrition Journal 2012.

Source-Medindia