Provincial Dietary Intake Study (PDIS): Micronutrient Intakes of Children in a Representative/Random Sample of 1- to <10-Year-Old Children in Two Economically Active and Urbanized Provinces in South Africa

In 1999, the National Food Consumption Survey found serious risk of dietary deficiency for a number of micronutrients in 1- to 9-year-old children in South Africa. To address these shortfalls, fortification with vitamin A, thiamine, riboflavin, niacin, vitamin B6, folic acid, iron and zinc of maize meal and bread flour was made mandatory in 2003. The aim of this study was to examine micronutrient intakes of 1- to <10-year-old children after nearly 20 years of fortification in two of the most urbanized and economically active provinces, Gauteng (GTG) and the Western Cape (WC). A multistage stratified cluster random sampling design and methodology was used. Households were visited by fieldworkers who interviewed caregivers and obtained dietary intake data by means of a multiple-pass 24-h recall. Two additional 24-h recalls were completed among a nested sample of 146 participants to adjust the single 24-h recall data of the total sample using the National Cancer Institute Method. Results show that median intake of all the fortification nutrients were above the estimated average requirement (EAR), with the only concern being folate in the WC. Between a quarter and a third of children in the WC, where maize porridge intake was significantly lower than in GTG, had a folate intake below the EAR. Nutrients that are not included in the fortification mix that remain a serious concern are calcium and vitamin D, with intake of dairy and vitamin D sources being very limited in both provinces. The improvement in micronutrient intakes of children is encouraging, however the outstanding nutrient deficiency risks need attention.

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Do you ever cut the size of meals or skip any because there is not enough food in the house? 3a Has it happened in the past 30 days? 3b.
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Do you ever eat less than you should because there is not enough money for food? 4a.
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Do your children ever eat less than you feel they should because there is not enough money for food? 5a.
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Do your children ever say they are hungry because there is not enough food in the house? 6a.
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Do you ever cut the size of your children's meals or do they ever skip meals because there is not enough money to buy food? 7a.
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Do any of your children ever go to bed hungry because there is not enough money to buy food? 8a.
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Community  The National Cancer Institute (NCI) method [1] that was developed to distinguish withinperson from between-person variation, account for extreme intakes, including zero intake, and allow for adjustment for covariates and association analyses. The NCI method is used to adjust the measurement of the observed single 24-hour dietary intake data using data from the PDIS study, to establish usual intake, and thereby improve the validity of the results.
Two additional 24-hour dietary recalls were completed on a subsample of 148 (2 nd recall) and 146 (3 rd recall) children in the sample. The last five EAs in each province, mainly for logistical reasons, were visited three times a week apart for this purpose. Parents of children also needed to indicate whether the 24-hour recall was less, same or more than the child's usual intake. The data obtained from the three 24-hour recalls of the subsample were used to adjust the observed distributions of the single 24-hour recall completed by the larger sample for the effects of random within-person variation.
Using the NCI method, the available 3-day 24-hour recalls for the subgroup were used to estimate within-person variance and remove it from the first 24-hour recall. The balanced repeated replication (BRR) method [2] was used to do variance estimation with a Fay coefficient of 0.3. Two pseudo primary sampling units (PSU) were created per stratum by randomly selecting half of the PSU (or EA) in each stratum into one pseudo-PSU, and the rest in a second pseudo-PSU [2,3]]. Therefore 6 original strata were maintained with 12 pseudo-PSUs, two per stratum. Consequently, 8 BRR weights were created, taking the original sampling weights as well as the age and gender of each child in consideration.
When estimating usual intakes, covariates adjusted for in this study included province, type of residential area (urban formal, urban informal or rural), gender of the child and whether the intake of the 24-hour recall was less, the same or more than usual. The three age groups, namely 1 to <3 years, 3 to <6 years and 6 to <10 years were treated as subgroup options within the macros. The NCI method calculations should be interpreted at population level, and usual intakes for individuals within the group are not produced. The website accessed is: https://prevention.cancer.gov/research-groups/biometry/measurement-error-impact/softwaremeasurement-error and the software selected are for estimating usual intake distribution, specifically for single regularly-consumed nutrients, and the percentage of energy intake from selected macronutrients.