Background: Anaemia remains a public health concern, and the its prevalence varies between countries as well as between age, sex and levels of poverty. This study aims at examining the association between socio-demographic factors and anaemia among children aged 6–59 months in Namibia. Methods: Data was extracted from the 2013 Namibian Demographic Health Survey. The association between anaemia and other factors was examined with logistic regression. Results are reported in odds ratio (OR), with 95% confidence intervals (CI). Results: In total, 1,383 children aged 6–59 months had complete data and included in the analyses. Our study shows that there is a statistically significantly increased risk of anaemia among children from poorer households compared with the richest quintile. Also, there was a statistically significance supporting anaemia being more common among boys than girls. There was also a statistically significant negative effect related to age. Discussion: Our study shows that young children, boys and children in poorer households have an increased risk of anaemia. Considering the adverse impact of anaemia on child development, policies must prioritise factors exacerbating anaemia risk.
The NDHS aims to gather data, amongst other things, on key health indicators such as fertility, maternal and child health, and nutritional status of mothers and children, and it has been conducted four times, in 1992, 2000, 2006-2007, and 2013.17 In our study, data from the 2013 NDHS was used. The two-stage sampling frame used in the 2013 NDHS was mainly based on the frame for the Namibia Population and Housing Census during 2011, though with partial updates. Namibia consists of 6,102 enumeration areas (EAs), 2,818 in urban areas, with an average of 86 households in them, and 3,284 in rural areas, with an average of 74 households in them. A predefined number of urban and rural EAs within each of the 13 regions in Namibia, totaling 269 urban and 285 rural clusters, were decided before the randomization took place. Within these 26 areas, in the first stage, probability proportional to size was used to select the 554 clusters. In the second stage, 20 households were chosen with equal probability systematic sampling in each of the clusters, and the total sample size was, therefore, 11,080 households. Detailed information about the sampling methods and the entire survey can be found in the 2013/14 NDHS report.17 In each household, a questionnaire was used, in which all members of the household were listed, and covering information about assets, which was used to calculate a wealth index. Additionally, all women aged 15-49 years in the households responded to a face-to-face questionnaire, which included questions about their educational level, and their children’s use of vitamin A supplements and deworming medication. Additional to these questionnaires, hemoglobin, height and weight of the children were measured. In our study children aged 6–59 months whose parent participated in the 2013 NDHS and provided information for them were included. Hemoglobin was measured in 2,303 children aged 6 – 59 months.17 After restricting to children who had anemia tested, their height and weight measured, and a face-to-face interview conducted with their mother, we got a total sample size of 1,537 children. Hemoglobin testing was performed by trained health technicians, by drawing a drop of capillary blood from a child’s fingertip or heel. The blood was drawn into a micro-cuvette and analyzed with a battery portable HemoCue photometer (HemoCue AB, Ängelholm, Sweden) that displays the hemoglobin concentration. We followed the WHO criteria and defined anemia as an Hb level of ≤ 11.0 g/dL.2 Height and weight were measured lying down for children below 24 months and for older children was measured standing. In our analyses, we used sex, place of residence, age, household wealth status, maternal education, received vitamin A supplement, received deworming medication, wasted, underweight, and stunted as exposure variables. These socioeconomic variables have previously been reported as being associated with anemia in children under 5. For the variable sex, girls were defined as the exposure group. Age was grouped as 6–11 months (reference group), 12–23 months, 24–35 months, 36–47 months, and 48–59 months. For place of residence, urban was used as reference and rural as exposure. The household wealth index was compiled in the NDHS dataset using the principle component analysis of asset variables, which are then categorized into quintiles, 17 with the highest wealth quintile as reference group. Questions about household characteristics (roofing type, flooring type, cooking fuel), possession of durable goods (bicycle, radio, television) and access to basic services (electricity, toilet, source of drinking water) were used to compile the household assets.17 This method is considered the most reliable measure of household socio-economic position.27 We used the lowest quintile as a reference group. Maternal education was divided into no education (defined as never went to school), primary education (attended school for 1–7 years), secondary education (attended school for 8–12 years) and higher education (attended university studies or similar) with secondary education used as the reference group. For received vitamin A supplement, received deworming medication was used as the exposure group. In our analyses, we excluded responses of do not know regarding vitamin A supplement and deworming medication(227 individuals and 405 individuals respectively) from analyses. Children were classified as stunted for a low height-for-age, as underweight for a low weight-for-age, and as wasted for low weight-for-height, according to the WHO child growth criteria.17 Descriptive statistics were performed with adjustments for the sampling weights of the NDHS. The weights are used to ensure a national representative survey sample for NDHS’s two-stage stratified cluster sampling methodology, which leads to a non-proportional distribution of sample divisions across regions.17 Multivariable logistic regression was applied to study the association between anemia and other factors. Estimates from this were presented with odds ratios (ORs) and 95% confidence intervals (CI). Stratified estimates were applied for sex. In these analyses, 1,383 children were included, whereas 154 participants were excluded because of missing data, either for use of Vitamin A, use of deworming medicine or no data for weight and/or height. To evaluate whether the drop-out because of lack of interview data might affect our results, a complementary analysis was performed on the 2,208 children aged 6–59 months with haemoglobin data, anthropometric data, and socioeconomic data (not including mother’s education). These analyses consequently did not include the variables mother’s education, vitamin A supplements and deworming medication. Furthermore, we conducted logistic regression without sample weights. This was done as the sample weights were calculated for the whole NDHS, while our study was based on a limited part of the sample due to our inclusion criteria, which meant that only mothers of 6–59 months old children with all required measurements was included. This limits our data to on average less than 2.5 children per EA in comparison to the 20 household per EA that was sampled, and this causes potential bias due to unstable sample weights. Statistical significance was set at 0.05. The statistical analyses were performed using STATA statistical software (Version 13; The StataCorp LP, College Station, Texas). We checked whether collinearity between stunting, underweight and wasting might affect our estimates by performing analyses with one of them at a time in separate logistic regressions (results not shown). We have not evaluated whether collinearity might affect our results in any other way. The DHS is conducted in countries with which WHO have established collaborations. Ethical clearance was obtained from WHO and the participating individual countries’ ethical committees before the surveys were conducted. Informed consent was obtained from legal guardian for participation in the study before individuals were interviewed. The DHS data that was used for the current study is available freely on a public domain (downloaded from http://www.dhsprogram.com/data/dataset_a dmin/download-datasets.cfm) after completion of a user’s agreement and the granting of access. No separate permission is required for data usage and publication.
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