Development of a dichotomous indicator for population-level assessment of dietary diversity in women of reproductive age

Background: Dietary diversity is a key element of diet quality, but diets of women of reproductive age (WRA; aged 15-49 y) in resource-poor settings are often deficient in a range of micronutrients. Previous work showed associations between simple food-group diversity indicators (FGIs) and micronutrient adequacy among WRA. For operational and advocacy purposes, however, there is strong demand for a dichotomous indicator reflecting an acceptable level of dietary diversity. Objective: The aim of the study was to develop a dichotomous indicator of dietary diversity inWRA. Methods: We performed a secondary analysis of 9 data sets containing quantitative dietary data from WRA in resource-poor settings (total n = 4166). From the raw dietary data, we calculated an individual "mean probability of adequacy" (MPA) across 11 micronutrients. Several candidate FGIs were constructed. Indicator performance in predicting an MPA > 0.60 was assessed within each data set by using receiver-operating characteristic analysis and sensitivity and specificity analysis at various FGI cutoffs. The analysis was performed separately for nonpregnant and nonlactating (NPNL) women and for lactating women. Results: We identified 2 "best candidate" dichotomous indicators on the basis of 9- or 10-point food-group scores (FGI-9 and FGI-10) with a cutoff of ≥ 5 food groups. Both were significantly correlated to MPA in each site (P < 0.001). Areas under the curve were moderate, ranging from 0.62 to 0.82 among NPNL women and from 0.56 to 0.90 among lactating women. Comparisons of results slightly favored FGI-10 for all women. Conclusions: When resource-intensive dietary methods are not feasible, a simple dichotomous indicator based on a cutoff of ≥ 5 of 10 defined food groups reflects "minimum dietary diversity for women of reproductive age." According to the conclusions of a consensus meeting of experts, this indicator is well suited for population-level assessment, advocacy, and possibly also for tracking of change in dietary diversity across time.