Socioeconomic inequalities in underweight, overweight, and obesity among women in Malawi: a cross-sectional analysis of the 2024 Malawi demographic and health survey

Abstract

Malnutrition remains a major public health concern among women in low-and middle-income countries, where undernutrition and overnutrition increasingly coexist. This pattern reflects rapid socioeconomic, dietary, and lifestyle transitions that disproportionately affect women of reproductive age. In sub-Saharan Africa, urbanization, changing food environments, and socioeconomic inequalities are associated with rising overweight and obesity while undernutrition persists among disadvantaged populations. This study examined the prevalence, socioeconomic inequalities, and determinants of underweight, overweight, and obesity among women in Malawi. We conducted a cross-sectional analysis of nationally representative data from the 2024 Malawi Demographic and Health Survey (2024 MDHS). The analytic sample included 9,286 non-pregnant women aged 15–49 years with valid anthropometric measurements. All analysis incorporated sampling weights, clustering, and stratification. Body mass index (BMI) was calculated as weight in kilograms divided by height in meters squared (kg/m²) and categorized using World Health Organization criteria as underweight (< 18.5 kg/m²), normal weight (18.5–24.9 kg/m²), overweight (25.0–29.9 kg/m²), and obesity (≥ 30.0 kg/m²). Survey-weighted descriptive statistics were used to estimate the prevalence across sociodemographic characteristics. Socioeconomic inequality was assessed using concentration indices based on household wealth ranking. Multinomial logistic regression was used to identify factors associated with underweight, overweight, and obesity, using normal weight as the reference category. Overall, 6.9% of women were underweight, 65.3% had normal weight, 17.9% were overweight, and 9.9% were obese. Overweight and obesity were substantially more prevalent in urban areas than in rural areas (overweight: 24.9% vs. 16.5%; obesity: 22.2% vs. 7.4%). Concentration index analysis showed that obesity was strongly concentrated among wealthier women (Wagstaff CI = 0.268, Erreygers CI = 0.106), whereas underweight was concentrated among poorer women (Wagstaff CI = -0.162, Erreygers CI = -0.045); the national overweight gradient was not statistically significant once clustering was accounted for. In adjusted multinomial models, urban residence and membership in the richer and richest wealth quintiles were associated with higher odds of obesity, but urban residence and wealth quintile were not significantly associated with underweight. Women in the Northern region had lower odds of both underweight and obesity than women in the Central region. Current contraceptive use was associated with lower odds of obesity. No examined factor was significantly associated with overweight after adjustment. Malawi faces a clear double burden of malnutrition among women of reproductive age, but this burden is not uniform: obesity is concentrated among wealthier, urban women, and underweight is concentrated among poorer, rural women, whereas overweight shows no significant socioeconomic or residential patterning. This distinction indicates that underweight, overweight, and obesity require separate policy attention rather than a single undifferentiated nutrition response. Integrated, equity-oriented nutrition policies that simultaneously target both ends of the BMI spectrum are needed to reduce health disparities among women in Malawi.