Relationship between household air pollution from biomass smoke exposure, and pulmonary dysfunction, oxidant-antioxidant imbalance and systemic inflammation in rural women and children in Nigeria.

BACKGROUND

Exposure to particulate matter from burning biomass fuels is believed to affect oxidant-antioxidant balance and to induce oxidative stress.

METHODS

Fifty-nine mother-child pairs from 59 households that used firewood exclusively for cooking in three rural communities in southwest Nigeria underwent blood test for albumin, pre-albumin, retinol-binding protein (RBP), superoxide dismutase (SOD), vitamins C, vitamin E, malondialdehyde (MDA) and C-reactive protein (CRP). Spirometry was performed and indoor levels of PM2.5 were determined.

RESULTS

Mean age (± SD; years) of mothers and children was 43.0±11.7 and 13.6±3.2, respectively. The median indoor PM2.5 level was 1575.1 µg/m3 (IQR 943.6--2847.0, p<0.001), which is substantially higher than the World Health Organization (WHO) standard of 25 µg/m3. The mean levels of pre-albumin (0.21±0.14 g/dL) and RBP (0.03±0.03 g/dL) in women were significantly lower than their respective normal ranges (1-3 g/dL and 0.2-0.6 g/dL, respectively, p<0.05). Similarly, the mean levels of pre-albumin (0.19±0.13 g/dL) and RBP (0.01±0.01 g/dL) in children were significantly lower than the respective normal ranges (1-3 g/dL and 0.2-0.6 g/dL, respectively, p<0.05). Mean serum concentrations of MDA in children (5.44±1.88 µmol/L) was positively correlated to serum concentrations of CRP (r=0.3, p=0.04) and negatively correlated to lung function (FEV1/FVC) in both mothers and children (both r=-0.3, p<0.05). Also, regression analysis indicates that CRP and SOD are associated with lung function impairment in mothers (-2.55±1.08, p<0.05) and children (-5.96±3.05, p=0.05) respectively.

CONCLUSION

Exposure to HAP from biomass fuel is associated with pulmonary dysfunction, reduced antioxidant defense and inflammation of the airways. Further studies are needed to better define causal relationships and the mechanisms involved.