Effect of individual, household and regional socioeconomic factors and PM2.5 on anaemia: A cross-sectional study of sub-Saharan African countries

A cross-sectional analysis of ambient fine particulate matter (PM2.5) exposure and haemoglobin levels in children aged under 5 years living in 36 countries

Low haemoglobin (Hb) concentrations and anaemia in children have adverse effects on development and functioning, some of which may have consequences in later life. Exposure to ambient air pollution is reported to be associated with anaemia, but there is little evidence specific to low- and middle-income countries (LMICs), where childhood anaemia prevalence is greatest. We aimed to determine if long-term ambient fine particulate matter (≤2.5 μm in aerodynamic diameter [PM_2.5]) exposure was associated with Hb levels and the prevalence of anaemia in children aged <5 years living in 36 LMICs. We used Demographic and Health Survey data, collected between 2010 and 2019, which included blood Hb measurements. Satellite-derived estimates of annual average PM_2.5 was the main exposure variable, which was linked to children's area of residence. Anaemia was defined according to standard World Health Organization guidelines (Hb < 11 g/dL). The association of PM_2.5 with Hb levels and anaemia prevalence was examined using multivariable linear and logistic regression models, respectively. We examined whether the effects of ambient PM_2.5 were modified by a child's sex and age, household wealth index, and urban/rural place of residence. Models were adjusted for relevant covariates, including other outdoor pollutants and household cooking fuel. The study included 154,443 children, of which 89,904 (58.2%) were anaemic. The country-level prevalence of anaemia ranged from 15.8% to 87.9%. Mean PM_2.5 exposure was 33.0 (±21.6) μg/m³. The adjusted model showed that a 10 μg/m³ increase in annual PM_2.5 concentration was associated with greater odds of anaemia (OR = 1.098 95% CI: 1.087, 1.109). The same increase in PM_2.5 was associated with a decrease in average Hb levels of 0.075 g/dL (95% CI: 0.081, 0.068). There was evidence of effect modification by household wealth index and place of residence, with greater adverse effects in children from lower wealth quintiles and children in rural areas. Exposure to annual PM_2.5 was cross-sectionally associated with decreased blood Hb levels, and greater risk of anaemia, in children aged <5 years living in 36 LMICs.

Spatial distributions and determinants of anaemia among adolescent girls in Ethiopia: a secondary analysis of EDHS 2016 - a cross-sectional study

OBJECTIVE

This study aimed to investigate the spatial distributions and determinants of anaemia among adolescent girls in Ethiopia. Exploring the spatial epidemiology of anaemia and identifying the risk factors would inform policymakers to come up with evidence-based prevention strategies for anaemia, especially in adolescent girls, who are the most affected segment of the population.

METHODS

Secondary analysis of the Ethiopian Demographic and Health Survey 2016 was conducted. A total of 3172 adolescents were included in the analysis. The Bernoulli model was fitted using SaTScan V.9.6 to identify hotspot areas and the geospatial pattern and prediction of anaemia were mapped using ArcGIS V.10.8. A multilevel logistic regression model was fitted to identify factors associated with anaemia among adolescent girls. Adjusted OR with 95% CI was calculated and variables having a p value less than 0.05 were statistically significant factors of anaemia.

RESULT

The overall prevalence of anaemia among adolescent girls in Ethiopia was 23.8 (22.4 to 25.3), with significant spatial variations across the country. The SaTScan analysis identified a primary cluster in the eastern, northeastern and southeastern parts of Ethiopia (loglikelihood ratio=39, p<0.001). High anaemia prevalence was observed in eastern parts of the country. In the multivariable multilevel logistic regression analysis, no formal education (adjusted OR (AOR)=1.49, 95% CI 1.05 to 2.12), Afar (AOR=3.36, 95% CI 1.87 to 6.05), Somali (AOR=4.63, 95% CI 2.61 to 8.23), Harari (AOR=1.90, 95% CI 1.32 to 4.10), Dire Dawa (AOR=2.32, 95% CI 1.32 to 4.10) and high cluster altitude (AOR=1.37, 95% CI 1.03 to 1.82) were significantly associated with anaemia.

CONCLUSION

The national distributions of anaemia varied substantially across Ethiopia. Educational status, region and cluster altitude were significantly associated with anaemia in the multivariable logistic regression model. Thus, targeted public health interventions for adolescent girls should be implemented in the hotspot areas.