Short-Term Effects of Air Pollution on Wheeze in Asthmatic Children in Fresno, California

BACKGROUND: Although studies have demonstrated that air pollution is associated with exacerbation of asthma symptoms in children with asthma, little is known about the susceptibility of subgroups, particularly those with atopy. OBJECTIVE: This study was designed to evaluate our a priori hypothesis that identifiable subgroups of asthmatic children are more likely to wheeze with exposure to ambient air pollution. METHODS: A cohort of 315 children with asthma, 6-11 years of age, was recruited for longitudinal follow-up in Fresno, California (USA). During the baseline visit, children were administered a respiratory symptom questionnaire and allergen skin-prick test. Three times a year, participants completed 14-day panels during which they answered symptom questions twice daily. Ambient air quality data from a central monitoring station were used to assign exposures to the following pollutants: particulate matter <= 2.5 mu m in aerodynamic diameter, particulate matter between 2.5 and 10 mu m in aerodynamic diameter (PM(10-2.5)), elemental carbon, nitrogen dioxide (NO(2)), nitrate, and O(3). RESULTS: For the group as a whole, wheeze was significantly associated with short-term exposures to NO(2) [odds ratio (OR) = 1.10 for 8.7-ppb increase; 95% confidence interval (CI), 1.02-1.20] and PM(10-2.5) (OR = 1.11 for 14.7-mu g/m(3) increase; 95% CI, 1.01-1.22). The association with wheeze was stronger for these two pollutants in children who were skin-test positive to cat or common fungi and in boys with mild intermittent asthma. CONCLUSION: A pollutant associated with traffic emissions, NO(2), and a pollutant with bioactive constituents, PM(10-2.5), were associated with increased risk of wheeze in asthmatic children living in Fresno, California. Children with atopy to cat or common fungi and boys with mild intermittent asthma were the subgroups for which we observed the largest associations

Male fetal loss in the U.S. following the terrorist attacks of September 11, 2001

Background: The secondary sex ratio (i.e., the odds of a male birth) reportedly declines following natural disasters, pollution events, and economic collapse. It remains unclear whether this decline results from an excess of male fetal loss or reduced male conceptions. The literature also does not converge as to whether the terrorist attacks of September 11, 2001 induced "communal bereavement", or the widespread feeling of distress among persons who never met those directly involved in the attacks. We test the communal bereavement hypothesis among gravid women by examining whether male fetal deaths rose above expected levels in the US following September 11, 2001. Methods: We apply interrupted time-series methods to all fetal deaths at or greater than the 20(th) week of gestation in the US from 1996 to 2002. Time-series methods control for trends, seasonality, and other forms of autocorrelation that could induce spurious associations. Results: Results support the hypothesis in that the fetal death sex ratio (i.e., the odds of a male fetal death) increased above its expected value in September 2001. Additional analysis of the secondary sex ratio indirectly supports that the terrorist attacks may have threatened the gestation of male more than female fetuses. Conclusions: Societal responses to events such as September 11, 2001 do not appear confined only to persons who have ever met the deceased. The fetal death sex ratio in the US population may serve as a sentinel indicator of the degree to which pregnant women react to population stressors