Trends in Socioeconomic Inequalities and Prevalence of Anemia Among Children and Nonpregnant Women in Low- and Middle-Income Countries

Key Points Question How did anemia inequalities change over time in low- and middle-income countries? Findings In this cross-sectional study of 163 419 children aged 6 to 59 months and 304 202 nonpregnant girls and women aged 15 to 49 years, the socioeconomic inequalities of anemia did not decrease among children in approximately 80% of low- and middle-income countries. For nonpregnant women, that figure was approximately 60% of low- and middle-income countries. Meaning To reduce the anemia inequalities found in most low- and middle-income countries, future efforts should attend to policies designed to reach vulnerable groups, specifically those with lower socioeconomic status.


Position: Education (or Maternal Education in the Case of Children)
We also examined anemia inequalities for another dimension of socioeconomic position: education (or maternal education in the case of children) using the same analysis method as that employed when examining household wealth. Education was measured as the reported number of education years. The children and non-pregnant women in this study were separately ranked from the lowest education level (rank 0) to the highest (rank 1) in order to estimate their positions in the cumulative distribution of socioeconomic status. 15 The education-related slope index of inequality (SII) and the relative index of inequality (RII) were calculated to determine absolute and relative socioeconomic inequalities of anemia, respectively. The annualized changes of the education-related SII and RII were calculated to adjust for the time difference between the earliest and the most recent surveys.
The education-related SII and RII of total anaemia among children was −8.37% and 0.71 (eTable 9). For children, the education-related SII and RII were significantly negative and less than 1 in 32 of 45LMICs, respectively (eTable 9). The education-related SII and RII of total anaemia among non-pregnant women was −4.88% and 0.80, respectively (eTable 10). For non-pregnant women, the education-related SII and RII were significantly negative and less than 1 in 25 countries, respectively (eTable 10). For example, the education-related SII for Ethiopia was -16.79 (-18.94 to -14.63), signifying that moving from the bottom to the top of the education distribution was associated with an estimated decrease of 16.79 cases of anemia per 100 non-pregnant women (eTable 10). Among children, the annualized changes in the education-related SII were not significantly different from 0 in 18 of the 24 LMICs (eTable 11). Among pregnant women, the changes in the education-related SII were not significantly different from 0 in 15 of the 25 LMICs.
However, the changes in the education-related SII for the countries of Sierra Leone, Guinea, and Cameroon represented annualized decreases among non-pregnant women, indicating an increase in socioeconomic inequalities (eTable 12 According to WHO standards, total anaemia was defined as Hb < 11 g/dL for children aged 6-59 months; severe anaemia was defined as Hb < 7 g/dL. 9,17 We used the above cross-sectional data set (the first data set) for the estimates of anaemia prevalence among children. According to WHO standards, total anaemia was defined as Hb < 12 g/dL for non-pregnant women aged 15-49 years; severe anaemia was defined as Hb < 8 g/dL. We used the above cross-sectional data set (the second data set) for the estimates of anaemia prevalence among non-pregnant women. All estimates used to determine anemia were weighted and proved appropriate for the DHS complex survey design.
Estimates of the prevalence of total and severe anemia among non-pregnant women were adjusted using world population data obtained from the WHO. According to WHO standards, total anaemia was defined as Hb < 11 g/dL for children aged 6-59 months; severe anaemia was defined as Hb < 7 g/dL. 9,17 We used above repeated cross-sectional dataset (The third dataset) for the analyses of the annualized changes. All estimates used to determine anemia were weighted and proved appropriate for the DHS complex survey design. The changes in the prevalences of total and severe anemia were measured by the annual absolute change in percentage points and were estimated through a calculation of the difference between anemia prevalence in the earliest and most recent surveys divided by the number of years between these two surveys. According to WHO standards, total anaemia was defined as Hb < 12 g/dL for non-pregnant women aged 15-49 years; severe anaemia was defined as Hb < 8 g/dL. We used above repeated cross-sectional dataset (The four dataset) for the analyses of the annualized changes. All estimates used to determine anemia were weighted and proved appropriate for the DHS complex survey design. The changes in the prevalences of total and severe anemia were measured by the annual absolute change in percentage points and were estimated through a calculation of the difference between anemia prevalence in the earliest and most recent surveys divided by the number of years between these two surveys. According to WHO standards, total anaemia was defined as Hb < 11 g/dL for children aged 6-59 months; severe anaemia was defined as Hb < 7 g/dL. We used the above cross-sectional dataset (the first dataset) for the estimates of education-related absolute and relative inequality among children women. All estimates used to determine anemia were weighted and proved appropriate for the DHS complex survey design.
The slope index of inequality (SII) and the relative index of inequality (RII) were calculated to determine the absolute and relative socioeconomic inequalities of anemia, respectively. SII > 0 and RII > 1 would indicate that individuals with lower socioeconomic status would be more likely to suffer from anemia, whereas the reverse inequality would indicate lower anemia prevalence among populations with lower socioeconomic status. According to WHO standards, total anaemia was defined as Hb < 12 g/dL for non-pregnant women aged 15-49 years; severe anaemia was defined as Hb < 8 g/dL. We used the above cross-sectional dataset (the second dataset) for the estimates of absolute and relative inequality among non-pregnant women. All estimates used to determine anemia were weighted and proved appropriate for the DHS complex survey design. The slope index of inequality (SII) and the relative index of inequality (RII) were calculated to determine the absolute and relative socioeconomic inequalities of anemia, respectively. SII > 0 and RII > 1 would indicate that individuals with lower socioeconomic status would be more likely to suffer from anemia, whereas the reverse inequality would indicate lower anemia prevalence among populations with lower socioeconomic status. According to WHO standards, total anaemia was defined as Hb < 11 g/dL for children aged 6-59 months; severe anaemia was defined as Hb < 7 g/dL. We used above repeated cross-sectional dataset (The third dataset) for the analyses of the annualized changes. All estimates used to determine anemia were weighted and proved appropriate for the DHS complex survey design. The annualized changes of the SII and RII were calculated to adjust for the interval of time between the earliest and most recent surveys. Positive values for the annualized change of the SII and RII indicate a reduction in inequality, whereas negative values indicate an increase in inequality. According to WHO standards, total anaemia was defined as Hb < 12 g/dL for non-pregnant women aged 15-49 years; severe anaemia was defined as Hb < 8 g/dL. We used above repeated cross-sectional dataset (The four dataset) for the analyses of the annualized changes. All estimates used to determine anemia were weighted and proved appropriate for the DHS complex survey design. The annualized changes of the SII and RII were calculated to adjust for the interval of time between the earliest and most recent surveys. Positive values for the annualized change of the SII and RII indicate a reduction in inequality, whereas negative values indicate an increase in inequality. According to WHO standards, total anaemia was defined as Hb < 11 g/dL for children aged 6-59 months; severe anaemia was defined as Hb < 7 g/dL. We used the above cross-sectional dataset (the first dataset) for the estimates of education-related absolute and relative inequality among children. All estimates used to determine anemia were weighted and proved appropriate for the DHS complex survey design. The slope index of inequality (SII) and the relative index of inequality (RII) were calculated to determine the absolute and relative socioeconomic inequalities of anemia, respectively. SII > 0 and RII > 1 would indicate that individuals with lower socioeconomic status would be more likely to suffer from anemia, whereas the reverse inequality would indicate lower anemia prevalence among populations with lower socioeconomic status. According to WHO standards, total anaemia was defined as Hb < 11 g/dL for children aged 6-59 months; severe anaemia was defined as Hb < 7 g/dL. We used above repeated cross-sectional dataset (The third dataset) for the analyses of the annualized changes. All estimates used to determine anemia were weighted and proved appropriate for the DHS complex survey design. The annualized changes of the SII and RII were calculated to adjust for the interval of time between the earliest and most recent surveys. Positive values for the annualized change of the SII and RII indicate a reduction in education-related inequality, whereas negative values indicate an increase in educationrelated inequality. According to WHO standards, total anaemia was defined as Hb < 12 g/dL for non-pregnant women aged 15-49 years; severe anaemia was defined as Hb < 8 g/dL. We used above repeated cross-sectional dataset (The four dataset) for the analyses of the annualized changes. All estimates used to determine anemia were weighted and proved appropriate for the DHS complex survey design. The annualized changes of the SII and RII were calculated to adjust for the interval of time between the earliest and most recent surveys. Positive values for the annualized change of the SII and RII indicate a reduction in education-related inequality, whereas negative values indicate an increase in education-related inequality.