[Dietary habits of 2 populations of the province of Barcelona (I): design and validation of a semiquantitative questionnaire of frequency of food consumption].

BACKGROUND: The identification of associations between alimentary factors and specific chronic diseases has led to the development of valid diet measurement methods. In the present article the design and validation of a questionnaire on the frequency of food consumption is reported.
METHODS: From an initial sample of 1,034 inhabitants of two populations in the province of Barcelona, Spain, a sample stratified by age, sex and population of 64 individuals between 13-70 years of age was randomly selected. A semiquantitative questionnaire was initially given to 58 of the 64 subjects including 39 foods or groups of food and these were instructed as to how to follow a registry of food for 7 days in two different periods. The intakes of energy products, macronutrients, fiber, cholesterol and vitamins C, A and E were estimated by the two methods were compared.
RESULTS: The means of nutrients estimated were lower in the questionnaire than those obtained by the reports of foods with the exception of the intake of carbohydrates. The range of the correlation coefficients for the values obtained by both methods was of 0.17 for vitamin E and 0.54 for the monounsaturated fatty acids which, after correction for the alternation factor, were found to be 0.20 and 0.67, respectively. Thirty-nine percent of the individuals were classified within the quintile of low consumption with 33% being within the quintile of greatest consumption.
CONCLUSIONS: The use of a semiquantitative questionnaire may be useful to describe the dietary habits in a given population and fundamentally when the population studied is to be classified according to the normal consumption of energy and macronutrients.