Regional and sex inequalities in the prevalence of underweight in adults in 48 sub-Saharan African countries: a multi-country descriptive analysis

Abstract

Adult underweight remains a persistent yet underrecognized public health concern in sub-Saharan Africa (SSA), with marked geographic and sex-based inequalities in its prevalence. underweight remains. Underweight reflects not only a lower body mass but also the broader consequences of chronic nutrient deficiencies, inadequate food access, and social and economic marginalization. However, comprehensive, sex-disaggregated, multi-country assessments of adult underweight individuals across the region remain limited. Understanding underweight, especially how its prevalence differs by sex and across regions, is critical for designing equitable nutrition policies and reducing health disparities. This study assessed the prevalence and distribution of underweight adults (BMI < 18.5 kg/m²) across 48 sub-Saharan African countries. The data were obtained from the WHO Inequality Monitor platform and validated through cross-referencing with the WHO Global Health Observatory (GHO) database. Country-level and regional estimates were generated, and sex-disaggregated analyses were conducted to examine inequalities between men and women across countries and sub regions. The overall prevalence of adult underweight in SSA was 11.7%, indicating a low-to-moderate public health burden, but there was marked heterogeneity across countries, ranging from 4.2% in Seychelles to 32.3% in Eritrea. The highest prevalence was observed in Eritrea, Equatorial Guinea, Ethiopia, and the Central African Republic. East Africa (16.2%) and Central Africa (13.9%) presented the highest regional prevalence rates. Pronounced sex-based disparities observed among males and females. In most countries and all sub regions, the prevalence of underweight was higher among men than women, particularly in Eastern and Southern Africa. Adult underweight in sub-Saharan Africa remains a significant and unevenly distributed public health problem, with clear regional clustering and substantial sex-based inequalities. The coexistence of widespread male underweight and persistent female vulnerability in specific contexts underscores the limitations of uniform nutrition policies. These findings justify the need for sex-responsive, region specific, and context-appropriate nutrition interventions that address adult underweight across the life course in SSA.