Slim north, fat south: explaining regional differences in abnormal weights in Nigeria

Weight abnormalities (underweight, overweight, and obesity) can cause life-threatening ailments. This study investigates disparities in the prevalence of underweight, overweight, and obesity between northern and southern Nigeria and their associated factors. Using the 2018 Nigeria Demographic and Health Survey (NDHS), the study analysed a sample of 12,333 women with complete records of body mass index. The study found that southern women had lower odds of being underweight than women in the north, but the reverse was the case for overweight and obesity. The prevalence of underweight was 11.6%, and it varies from 6.9% in the southern state of Enugu to 31.6% in the northern state of Jigawa. The national prevalence of overweight was 17.9%, ranging from 6.7% in Jigawa State of the northern region to 39.9% in Lagos State of the south. Similarly, the prevalence of obesity in the north was 6.1% compared to 14.4% in the south, with Anambra State of the southern region recording the highest figure of 35.5% compared to 2.1% in the Yobe State of the northern region. In all, the rate of abnormal weight was significantly higher in the south than in the north. However, the type of weight abnormality varies between the two regions. Religion, education, use of contraceptives, and wealth were associated with the three forms of abnormal weights. However, while religion was significantly associated with obesity in the north, the association was not significant in the south. This study found that wealth and education have dissimilar influences on overnutrition. While the odds of being overweight and obese increase with wealth, being educated up to a secondary level significantly reduces the odds in Nigeria and across the two regions.