Predictors of vitamin A rich food consumption among women living in households growing orange-fleshed sweetpotatoes in selected regions in Uganda.

Objective: Vitamin A deficiency (VAD) has serious public health consequences including morbidity and mortality for populations in low and middle-income countries (LMICs), especially for children under 5 years and pregnant women. LMICs are at greater risk of VAD, in part due to low levels of consumption of vitamin A-rich foods most of which are plant-based, such as orange-fleshed sweet potatoes (OFSP), with lower bioavailability than animal sources of the vitamin A. Food-based approaches such as biofortification of OFSP, including promoting the consumption of vitamin A-rich biofortified staple crops, has been shown to be potentially effective in improving the status of vitamin A and other micronutrients. This study examined vitamin A-rich food consumption and its predictors among women of reproductive age from OFSP-growing households in two regions of Uganda. Methods: A cross-sectional survey was conducted among 617 OFSP growing households, focusing on women in the reproductive age group from the northern and eastern regions of Uganda. Households were not receiving any VAD-related intervention at the time of the survey. Quantitative data included vitamin A-rich food consumption, knowledge on vitamin A, and rich food sources dietary intake, using a 7-day food frequency questionnaire. Vitamin A consumption and risk of deficiency were estimated using the Hellen Keller International guide. Results: The majority of women in this study were either pregnant (80%) or lactating (17%). More than 70% of the study population had a weighted vitamin A rich food consumption mean score of <6 days per week, indicating a high risk of VAD. Knowledge about vitamin A [b (SE) = -0.18 (0.50), p < 0.001] was significantly and inversely associated with vitamin A rich food consumption. Conclusion: Components of food insecurity such as availability, affordability, utilization, and changing food preferences may contribute to the unexpected inverse relationship between knowledge and consumption of vitamin A rich foods. Scaling up biofortified food initiatives, including OFSP, can improve consumption of vitamin A rich foods with effective strategies to comprehensively address consumption barriers such as lack of nutrition education, cooking skills, and storage facilities, as well as low production levels and perceived contamination of biofortified foods.

Comparison of indicators of iron deficiency in Kenyan children.

BACKGROUND: In the absence of a feasible, noninvasive gold standard, iron deficiency (ID) is best measured by the use of multiple indicators. However, the choice of an appropriate single iron biomarker to replace the multiple-criteria model for screening for ID at the population level continues to be debated. OBJECTIVE: We compared ID defined as ≥ 2 of 3 abnormal ferritin (< 12 µg/L), soluble transferrin receptor (TfR; > 8.3 mg/L), or zinc protoporphyrin (ZP; > 80 µmol/mol) concentrations (ie, multiple-criteria model) with ID defined by abnormal concentrations of any of the independent candidate iron biomarkers (ferritin alone, TfR alone, or ZP alone) and TfR/ferritin index (ID, > 500). Values either were adjusted for inflammation [as measured by C-reactive protein (> 5 mg/L) and α(1)-acid glycoprotein (> 1 g/L) before applying cutoffs for ID] or were unadjusted. DESIGN: In this community-based cluster survey, capillary blood was obtained from 680 children (aged 6-35 mo) for measurement of iron status by using ferritin, TfR, and ZP. RESULTS: On the basis of the multiple-criteria model, the mean (±SE) prevalence of ID was 61.9 ± 2.2%, whereas the prevalences based on abnormal ferritin, TfR, or ZP concentrations or an abnormal TfR/ferritin index were 26.9 ± 1.7%, 60.9 ± 2.2%, 82.8 ± 1.6%, and 43.1 ± 2.3%, respectively, for unadjusted values. The prevalences of ID were higher for adjusted values only for low ferritin and an elevated TfR/ferritin index compared with the unadjusted values. The κ statistics for agreement between the multiple-criteria model and the other iron indicators ranged from 0.35 to 0.88; TfR had the best agreement (κ = 0.88) with the multiple-criteria model. Positive predictive values of ID based on the other iron indicators in predicting ID based on the multiple-criteria model were highest for ferritin and TfR. Receiver operating characteristic curve analysis indicated that TfR (AUC = 0.94) was superior to the other indicators in diagnosing ID based on the multiple-criteria model (P < 0.001). The inflammation effect did not appear to alter these observations appreciably. CONCLUSION: TfR better estimates the prevalence of ID in preschoolers than do ferritin, ZP, and the TfR/ferritin index on the basis of multiple indexes in a high inflammation, resource-poor setting. This trial was registered at clinicaltrials.gov as NCT101088958.

Correcting for inflammation changes estimates of iron deficiency among rural Kenyan preschool children.

The assessment of iron status where infections are common is complicated by the effects of inflammation on iron indicators and in this study we compared approaches that adjust for this influence. Blood was collected in 680 children (aged 6-35 mo) and indicators of iron status [(hemoglobin (Hb), zinc protoporphyrin (ZP), ferritin, transferrin receptor (TfR), and TfR/ferritin index)] and subclinical inflammation [(the acute phase proteins (APP) C-reactive protein (CRP), and α-1-acid glycoprotein (AGP)] were determined. Malaria parasitemia was assessed. Subclinical inflammation was defined as CRP >5 mg/L and/or AGP >1 g/L). Four groups were defined based on APP levels: reference (normal CRP and AGP), incubation (raised CRP and normal AGP), early convalescence (raised CRP and AGP), and late convalescence (normal CRP and raised AGP). Correction factors (CF) were estimated as the ratios of geometric means of iron indicators to the reference group of those for each inflammation group. Corrected values of iron indicators within inflammation groups were obtained by multiplying values by their respective group CF. CRP correlated with AGP (r = 0.65; P < 0.001), ferritin (r = 0.38; P < 0.001), Hb (r = -0.27; P < 0.001), and ZP (r = 0.16; P < 0.001); AGP was correlated with ferritin (r = 0.39; P < 0.001), Hb (r = -0.29; P < 0.001), and ZP (r = 0.24; P < 0.001). Use of CF to adjust for inflammation increased the prevalence of ID based on ferritin < 12 µg/L by 34% (from 27 to 41%). Applying the CF strengthened the expected relationship between Hb and ferritin (r = 0.10; P = 0.013 vs. r = 0.20; P < 0.001, before and after adjustment, respectively). Although the use of CF to adjust for inflammation appears indicated, further work is needed to confirm that this approach improves the accuracy of assessment of ID.