Differential Association of Hepatocellular Carcinoma Related to Hepatitis B Between Urban and Rural Areas in Africa Using Satellite Spatial Scaling Data

PURPOSE Sub-Saharan Africa carries one of the highest burdens of hepatocellular carcinoma (HCC) in the world, with hepatitis B virus (HBV) as the most common cause. Studies in several regions of the world suggest important cancer differences in rural versus urban settings, but limited studies have been performed in Africa.METHODSWe performed a scoping review and pooled analysis of studies on HCC in Africa. Using land use data from the European Space Agency, we calculated the distance in kilometers from each study site to the nearest rural area. Regression models were fit to estimate the association between distance to the nearest rural area and HBV, sex, and weighted mean age.RESULTSData from 57 studies including 10,907 patients across 36 towns/cities were included in our analysis. Proximity to rural areas was associated with a higher frequency of HBV-associated HCC in assessment of distance both at midpoint and at quartiles after controlling for country: risk ratio (RR) 1.71 (95% CI, 1.52 to 1.93) and RR 1.51 (95% CI, 1.25 to 1.84), respectively. No association was found between sex and proximity to a rural area: RR 1.02 (95% CI, 0.96 to 1.08). The weighted mean age across the four distance quartiles was 50.09, 53.43, 47.98, and 53.35 years with no statistically significant difference found across the quartiles (P =.81).CONCLUSIONIndividuals living in rural Africa have a higher rate of HBV-related HCC compared with other liver diseases. Increased HBV awareness efforts in these areas should be considered.