摘要 : Within a cohort of 846 inner - city asthmatic children aged 4 to 9 yr, we looked for subgroups that were more susceptible to the effects of summer ozone. Daily diaries were compared with ambient ozone levels to evaluate effect mod... 展开 Within a cohort of 846 inner - city asthmatic children aged 4 to 9 yr, we looked for subgroups that were more susceptible to the effects of summer ozone. Daily diaries were compared with ambient ozone levels to evaluate effect modification by demographic and environmental characteristics. Children born > 3 wk prematurely or weighing < 5.5 lb. Had greater declines in morning /100 peak ex - piratory flow rate (PEFR) (1.8/100 versus 0.3/100 per 15 ppb ozone , p> 0.05) and a higher incidence of morning symptoms (odds ratio = 1.42 versus 1.09 per 15 ppb ozone, p < 0.05 than did children who had been full - term infants of normal birthweight. 收起