Assessing change in diet-intervention research

Abstract

In nutrition-intervention research, it is important to consider the sensitivity of dietary assessment instruments to the changes in nutrient intake or dietary behavior under study. This presentation describes a measure called "responsiveness," an index of an instrument's sensitivity to change. Illustrations of this measure are from two randomized dietary-intervention trials that targeted reductions in fat intake: the Women's Health Trial (WHT), a trial to test whether fat reduction would reduce the risk of breast cancer, and the Eating Patterns Study (EPS), a trial to evaluate a self-help booklet to promote dietary change. In the WHT, a 4-d diet record (FDDR) was only slightly more responsive to dietary change than was a food-frequency questionnaire (FFQ). In the EPS, a fat-related diet-habits questionnaire was most responsive, followed by an FDDR and an FFQ. These data suggest that short, inexpensive measures such as FFQs or questionnaires that assess dietary habits can be as responsive as multiple-day diet records. More research is needed on the relative responsiveness of dietary assessment tools. Intervention studies should include at least two types of dietary assessment tools and the relative validity, reliability, and responsiveness of these tools should be reported as part of the study outcome.

The summary of diabetes self-care activities measure: results from 7 studies and a revised scale.

“…Table 2 shows the correlations between the dietary and exercise subscales and criterion variables. For dietary comparisons, criterion measures were derived from 3-or 4-day food records, food-frequency questionnaires (42,44), the Food Habits Questionnaires (45), and the Block Fat Screener (46). For exercise, comparisons were with the Stanford 7-Day Recall (47), the Physical Activity Scale for the Elderly (48), exercise self-monitoring data (33), or attendance at an exercise class.…”

Changes in dietary intake during a 6-year follow-up of an older population

“…Although the validity and reproducibility of the FFQ used in this study have been demonstrated, its ability to quantify changes in intake over long times has not been established. The FFQ approach has been found to be only slightly less responsive than multiple diet records in determining changes in fat intakes in an intervention study (Kristal et al, 1994), indicating that the FFQ is able to measure change and, if anything, tends to underestimate change in dietary intake. Another limitation of this study is the absence of a time-sequential component, that is, recruitment of a new group of adults aged 70 y and older in 1995a96, for the examination of time effects.…”

Weight-Loss Treatment-induced Physical Activity Associated with Improved Nutrition through Changes in Social Cognitive Theory Variables in Women with Obesity

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