Is outdoor air pollution associated with physician visits for allergic rhinitis among the elderly in Toronto, Canada?

BACKGROUND: While a number of studies suggest that air pollution is associated with allergic rhinitis in children, findings among adults have been equivocal. The aim of this study was to examine the relationship between outdoor air pollution and physician visits for allergic rhinitis among individuals>or=65 years of age in Toronto, Canada. METHODS: Physician visits were identified by using data from the Ontario provincial health insurance plan that is made available to all residents. Our analyses are based on 52,691 physician visits for allergic rhinitis among individuals>or=65 years of age in the Toronto metropolitan area between 1995 and 2000. Generalized linear models were used to regress daily counts of physician visits against daily measures of gaseous and particulate components of air pollution after controlling for seasonality, potential confounders (temperature, relative humidity, aeroallergens), overdispersion and serial correlation. RESULTS: A large number of comparisons were undertaken, with most showing no statistically significant associations between daily levels of air pollution and the number of physician visits for rhinitis. In contrast, an interquartile increase in the 10-day average of ragweed particles increased the mean number of daily rhinitis consultations by 6.4% (95% CI=0.7-12.4%). CONCLUSIONS: Our findings suggest that outdoor air pollution is a poor predictor of physician visits for allergic rhinitis among the elderly.

Evaluation of the validity of the Done nomogram in the management of acute salicylate intoxication.

To evaluate the validity of the Done nomogram in the management of acute adult salicylate intoxications, a retrospective review of cases at our institution was performed. The degree of severity (ie, asymptomatic, mild, moderate, or severe) as determined by plotting the serum concentration and time on the nomogram for 55 acute salicylate intoxications was compared with the degree of severity decided on by three experienced emergency physicians who based their decision on the clinical presentation of the cases and the original criteria devised by Done for each category of severity. Discordant classifications between the nomogram and the physicians provided a basis on which a predictive index for the nomogram and various subsets of cases could be determined. The calculated predictive index for the nomogram was 0.42, with the highest predictive index of 0.79 in the mild salicylate category. The nomogram tends to overpredict the severity of intoxication in the moderate and severe categories. There was no significant difference between predictive indexes of mixed versus nonmixed or enteric-coated acetylsalicylic acid versus plain acetylsalicylic acid cases, although the nomogram had a higher predictive index when used for concentrations drawn six to 12 hours after ingestion (P less than .01, Fisher's exact test). Decisions on management of an acute salicylate overdose should be based on clinical presentation and good judgment as well as the serum salicylate concentration in relation to the time of ingestion.