Abstract

Objectives: To investigate whether there is an association between risk of congenital anomaly and annual ward level exposure to air pollution in England during the 1990s.

Methods: A geographical study was conducted across four regions of England with population-based congenital anomaly registers, 1991-99. Exposure was measured as 1996 annual mean background SO2, PM10 and NO2 concentrations at census ward level (n=1474). Poisson regression, controlling for maternal age, area socioeconomic deprivation, and hospital catchment area was used to estimate relative risk for an increase in pollution from the 10th to the 90th centile.

Results: For non-chromosomal anomalies combined, relative risks were 0.99 (95%CI 0.93-1.05) for SO2, 0.97 (95%CI 0.84-1.11) for NO2, 0.89(95%CI 0.75-1.07) for PM10. For chromosomal anomalies, relative risks were 1.06 (95%CI 0.98-1.15) for SO2, 1.11 (95%CI 0.95-1.30) for NO2, 1.18 (0.97-1.42) for PM10. Raised risks were found for Tetralogy of Fallot and SO2 (RR=1.38, 95%CI 1.07-1.79), NO2 (RR=1.44, 95%CI 0.71-2.93) and PM10 (RR=1.48, 95%CI 0.57-3.84), of interest in the light of previously reported associations between this cardiac anomaly and other air pollutants.

Conclusions: While air pollution in the 1990s did not lead to sustained geographical differences in overall congenital anomaly rate in England, further research regarding specific anomalies is indicated.