Ambient air pollution and school children's respiratory health, lung functions and cardiopulmonary fitness in Hong Kong: A cross-sectional study.

摘要

To explore associations between air pollution and respiratory and cardiovascular health of school children, a cross-sectional study was conducted among 3,186 primary school children in P3 and P4 from three districts with different air pollution levels in Hong Kong during March to June in 2004.; In the past year preceding the study (May 2003 to April 2004), the annual means for PM10, NO2, SO2 and O3 were respectively 55.1 mug/m3, 51.4 mug/m3, 15.4 mug/m3, and 42.5 mug/m3 in the least-polluted district (LPD); 56.3 mug/m3, 64.7 mug/m3, 15.2 mug/m3, and 35.2 mug/m3 in the moderately-polluted district (MPD); and 63.8 mug/m3, 64.1 mug/m3, 22.2 mug/m3, and 31.7 mug/m3 in the highly-polluted district (HPD). The 99th percentiles were 178 mug/m3, 158 mug/m 3, 104 mug/m3, and 140 mug/m3 in the LPD; 169 mug/m3, 181 mug/m3, 106 mug/m 3, and 113 mug/m3 in the MPD; and 226 mug/m 3, 177 mug/m3, 140 mug/m3, and 137 mug/m 3 in the HPD. The average daily 1-h maximum O3 (peak O 3) was 83.7 mug/m3 in the LPD, 73.6 mug/m 3 in the MPD, and 64.8 mug/m3 in the HPD.; There were totally 2,641 (82.9%) children who participated in the study, and 2,203 participants were involved in analyses. After adjustment for confounding factors, girls living in the HPD had significantly increased odds ratios (ORs) for wheezing without cold (4.75), cough at night (1.71), phlegm without cold (3.61), compared with those in the LPD. Boys in the HPD had increased OR only for phlegm without cold (1.88). When comparing the MPD with LPD, the adjusted OR for cough at night achieved significance in girls (1.74) and marginal significance in boys (1.40). Sneeze with itchy-watery eyes and current/ever allergic rhinitis had negative associations with district. In comparison with LPD, the decreased OR for sneeze with itchy-watery eye in girls in HPD (0.65) reached statistical significance. Both boys and girls in MPD had significantly decreased ORs for current allergic rhinitis (0.72 and 0.50 respectively) and for ever allergic rhinitis (0.74 and 0.55 respectively). There were no significant differences in the prevalence rates of asthma and bronchitis between districts.; Lung function indices included FVC, FEV1, FEV 1/FVC, FEF25-75%, FEF25%, and FEF75%. Children in the HPD had lower FEV 1/FVC, FEF25-75%, and FEF25% than those in both the LPD and MPD, after controlling for their corresponding confounders. In comparison between the LPD and HPD, the adjusted mean differences for FEV1/FVC, FEF25-75%, and FEF25% were respectively 1.39%, 85 ml, and 113 ml in boys, and 1.60%, 86 ml, and 225 ml in girls. In addition, the decreased FEF75% of HPD was found in boys (62 ml) but not in girls. When comparing the MPD with LPD, the increased FEF25% was observed in girls in the LPD (158 ml), whereas boys in the LPD had lower FEF75% than those in the MPD (81 ml). There were no significant differences in children's FVC and FEV1 between districts.; The multistage fitness test (MFT) with the Matsuzaka's function was employed to predict cardiopulmonary fitness (VO2max) of children. After adjustment for the factors, girls in the LPD had significantly higher VO 2max than those in the MPD and HPD by 0.19 and 0.75 ml·kg -1 ·min-1 respectively. The VO 2max among boys in the LPD was 0.48 ml·kg-1 ·min -1 higher than those in the HPD. When we compared the VO 2max between students in MPD and HPD, higher VO2max in both boys and girls in the MPD were observed---by 0.49 and 0.56 ml·kg -1 ·min-1 respectively. In LPD, significantly higher VO2max values were observed in both boys and girls who were physically active (children who took part in sports and/or vigorous free play at least three times a week for at least 30 minutes each time) compared with those who were not (0.71 and 0.65 ml·kg-1 ·min -1 respectively), but those differences in VO2max among students in MPD and HPD were small and insignificant.; In conclusion, the current air pollution levels in Ho