Incidence of low birth weight and proximity to mining in Lubumbashi and Kipushi, DR Congo

Background. Previous studies have shown high exposure to trace metals in people living close to mining/smelters in Katanga. We determined the incidence of low birth weights (LBW) in Lubumbashi and Kipushi, cities that host zones with different degrees of environmental pollution caused by copper and cobalt mining and smelting.Methods. We used routinely collected birth data in 8 out of 12 existing health zones during one year (1 July 2018 to 30 June 2019). We compared the proportions of neonates with LBW according to the presence of mining/smelting in the health zones. We also looked in more detail into the data of 9 selected maternities where we only considered first-born neonates.Results. Of 202,028 births in Lubumbashi during the observation period, 145,512 (72%) were recorded in the studied health zones, of which 11,448 were LBW neonates (excluding premature births), i.e. 7.87/100 births. The incidence of LBW was 1.80 times higher (p<0.001) for the 3 health zones with mining (6,190/57,597 births; 10.75/100) than for the 5 health zones without mining (5,258/87,915 births; 5.98/100). In the 9 selected maternities, LBWs were recorded in 589/7,203 first-born neonates (8.18/100). The incidence was 2.75 times more frequent (p<0.001) for the 2 maternities very close (i.e. within sight) to mining (235/1,400 births; 16.78/100) than for the 7 maternities far from mining (354/5,803; 6.10/100).Conclusions. Based on the previous findings of high exposure to trace metals in people living close to mining, it is plausible that mining-related metal pollution plays a role in the spatial association observed in Lubumbashi between proximity to mining and the incidence of low birth weights.