Validation of the second version of a quantitative food-frequency questionnaire for use in Western Mali

Abstract

Objective: To assess the relative validity of the second version of a quantitative foodfrequency questionnaire (QFFQ), designed to measure the habitual food and nutrient intake in one season in rural populations in Western Mali, West Africa. Design: The dietary intake during the previous week was assessed with the 164-item QFFQ administered by interview. This was compared with the intake from a 2-day weighed record (WR) with weighed recipes. Setting: The village of Ouassala in the Kayes region, Western Mali. Subjects: Thirty-four women and 36 men aged 15 -45 years, from 29 households. Results: The QFFQ gave a lower intake of lunch and dinner and a higher intake of snacks than the WR. The discrepancies were larger for women than for men. The median proportion of subjects classified in the same quartile of intake was 29% for food groups and 36% for energy and nutrients. For classification into extreme opposite quartiles, the median proportion was 6% for food groups and 7% for energy and nutrients. Spearman's rank correlation for energy and nutrients ranged from 0.16 (% energy from protein) to 0.62 (retinol equivalents). Conclusions: The second version of the QFFQ tends to underestimate total food weight. The methods used for estimating food portion size should therefore be applied with caution. The changes made from the first version had little effect. The ability to rank subjects according to dietary intake is similar with both versions. The improved layout of the new QFFQ makes it a more user-friendly tool for comparing dietary intake between population groups and for measuring changes over time. The food-frequency questionnaire (FFQ) is often the most feasible method for collecting data on regular dietary intake from large population samples. Its advantages include quicker administration and processing, and subsequently lower costs and participant burden than alternative methods such as diet history or repeated 24-hour recalls. Although the FFQ has traditionally been used in epidemiological studies 1,2 , it can also be used to assess and monitor nutrition situations, and as a basis for policy planning 3 . The FFQ is a simple tool for ranking individuals according to dietary intake, but its ability to provide accurate quantitative measures of intake is generally limited 4 . Furthermore, FFQs should be developed and validated in the local setting to ensure that the method is adapted to the target population and culturally sensitive 5 . A number of recently published studies report the use of FFQs in various populations in South Africa 6 -12 . However, the application of FFQs in other African countries appears much more limited 13 -16 . To our knowledge, very few studies have been done on the development and validation of FFQs in African population groups 3,17 -20 , indicating a need for further development of quantitative methods for assessing their dietary intake. This paper describes the relative validity of the second version of a quantitative food-frequency questionnaire (QFFQ), designed to m...

Validation of food variety as an indicator of diet quality assessed with a food frequency questionnaire for Western Mali

“…The larger discrepancies in the index scores between the WRs and FFQ for women than for men confirm results from the two earlier validation studies (Torheim et al, 2001;Parr et al, 2002). Both studies concluded that the questionnaire Table 5 Crossclassification of subjects in quartiles (Q) of food variety score (FVS), diet diversity score (DDS) and mean adequacy ratio (MAR) from the food frequency questionnaire (FFQ) and from the weighed records (WR).…”

“…The two earlier validation studies published on the FFQ (Torheim et al, 2001;Parr et al, 2002) compared intake of foods and nutrients from the FFQ and the WR, and median Spearman's correlation coefficient was in the range of 0.3-0.4 for both foods and nutrients. Correct classification was in the order of 29-36% (median values), while median gross misclassification ranged from 4 to 7%.…”

“…The results from the two studies showed that both versions of the questionnaire could rank and categorise subjects according to the intake of foods and nutrients (Torheim et al, 2001;Parr et al, 2002). The FFQ did not determine absolute intakes equally well.…”

“…Food intake between meals was mainly recalled in study A (Torheim et al, 2001) and weighed in study B (Parr et al, 2002). The methods have been described in more detail elsewhere (Torheim et al, 2001;Parr et al, 2002).…”

“…The aim of this study was to assess the relative validity of the three diet quality indexes: food variety score (FVS), diet diversity score (DDS) and mean adequacy ratio (MAR), derived from a quantitative food frequency questionnaire (FFQ) developed for use in Western Mali. Data from two previous validation studies of the FFQ were used (Torheim et al, 2001;Parr et al, 2002). The reference method was a 2-day weighed record (WR).…”