Evaluation of dietary diversity scores to assess nutrient adequacy among rural Kenyan women

S.A. Ngala

Research output: Thesisinternal PhD, WU

Abstract

 

Evaluation of dietary diversity scores to assess nutrient  adequacy among rural Kenya women

S. A. Ngala

Abstract

Background:The major cause of micronutrient deficiencies are low intake due to monotonous diets, especially among women of child bearing age.  Dietary diversity score has been found to be a good proxy indicator for micronutrient adequacy. However, there are still outstanding methodological questions related to seasonal effects,  food intake methods, selection of foods and the cut-off for estimating the prevalence of acceptable nutrient adequacy. This thesis evaluated the performance of a simple dietary diversity score for assessing nutrient adequacy in the diets of rural women in Kenya.

Methods: The study was conducted in Mbooni Division, Makueni District, Kenya among non-pregnant, non-lactating women of reproductive age having a child between  2-5 years.  Food consumption data was collected by 3 non-consecutive 24hour-recalls and a qualitative 24hour-recall in pre-harvest (period 1, October 2007, n=73) and post-harvest (period 2, April 2008, n=203) seasons. Dietary diversity scores (DDS) were derived based on 10 and 13 food groups with minimum intake threshold per food group of 0 and 15 g respectively.  Mean probability of adequacy (MPA) was calculated based on intake of 11 micronutrients.

Results: The dietary diversity score (DDS) and mean probability of adequacy (MPA) were significantly but moderately associated in both seasons (r=0.40 and r=0.38 period 1 and 2) and the association was independent of season (p=0.45). The DDS from a qualitative  24 hour recall (DDSql)  showed little agreement with quantitative 24 hour recall (DDSqn) with a mean difference (DDSqn-DDSql) of -0.51±1.46 (Period 1) and -0.58±1.43 (period 2), with lower correlation between MPA and DDS for DDSql (r=0.14 and 0.19 in period 1 and 2, p>0.05) compared to DDSqn (r=0.40 and 0.54 in period 1 and 2, p<0.01). The Informative food-based scores and the food group-based scores were  moderately associated with mean probability of adequacy (r=0.54-0.59 in period 1; r=0.37- 0.45 in period 2) with higher values for informative food based scores. The Minimum Dietary Diversity of Women (MDD-W) and mean probability of adequacy were significantly but moderately associated in both seasons (r=0.43-0.58 in period 1; r=0.24-0.50 in period 2) with but the use of a cutoff of consuming 5 or more food groups as indication of nutrient adequacy resulted in high total misclassification  in both periods.

Conclusion: A dietary diversity score can be used as a simple proxy for micronutrient adequacy, independent of season. The dietary diversity score derived from qualitative free-listing 24-hour recall formed a poor indicator, needing further refinement to improve its performance. The informative food-based score performs moderately better  in predicting nutrient adequacy, but its advantages do not outway those of the food group-based scores, and the latter is therefore preferred. The Minimum Dietary Diversity score for Women, formed a good  indicator to predict nutrient adequacy, but using the cutoff of 5 or more food groups resulted in an overestimation of prevalence of adequate intake in our resource poor population.

 

 

Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Wageningen University
Supervisors/Advisors
  • Kok, Frans, Promotor
  • Brouwer, Inge, Co-promotor
  • Mwangi, A.M., Co-promotor
Award date9 Sep 2015
Place of PublicationWageningen
Publisher
Print ISBNs9789462574236
Publication statusPublished - 2015

Keywords

  • kenya
  • women's health
  • nutrients
  • trace elements
  • nutritional adequacy
  • diversity
  • rural population
  • quantitative methods
  • qualitative methods

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