BackgroundWe studied whether short-term exposure to air pollution was associated with non-specific abdominal pain in epidemiologic and animal studies.MethodsPatients visiting the emergency department with non-specific abdominal pain were identified in Edmonton (1992 to 2002, n = 95,173) and Montreal (1997 to 2002, n = 25,852). We calculated the daily concentrations for ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO), and particles <10 (PM10) or <2.5 (PM2.5) µm. A case crossover study design was used to estimate the odds ratio (OR) and 95% confidence interval (CI) associated with an increase in the interquartile range of the air pollutants. We investigated differential effects by age and sex. Mice were gavaged with urban particle extracts. In animal models, colonic motility was tested, and visceral abdominal pain was measured using a writhing test, and behavioral response to oil of mustard and neostigmine. Motility and pain was measured acutely (1.5 hours after gavage) and chronically (7-days and 21-days after gavage).ResultsEmergency department visits for non-specific abdominal pain were primarily by women between the ages of 15–24 years. Individuals aged 15 to 24 years were at increased risk of non-specific abdominal pain in Edmonton (same day CO: OR = 1.04, 95% CI = 1.02–1.06; and NO2: OR = 1.06, 95% CI = 1.03–1.09). The risk of air pollution among 15–24 year olds in Montreal was significantly positive (same day CO: OR = 1.11, 95% CI = 1.05–1.17; NO2: OR = 1.09, 95% CI = 1.01–1.16; SO2: OR = 1.17, 95% CI = 1.10–1.25; PM2.5: OR = 1.09, 95% CI = 1.04–1.15). Abdominal pain was increased by an acute gavage of pollution extract but not to chronic exposure to pollutants. Colonic transit was delayed following chronic but not acute exposure with the pollutants.ConclusionsEpidemiological and animal data suggest that short-term exposure to air pollution may trigger non-specific abdominal pain in young individuals.

Objectives were to assess and estimate an association between exposure to ground-level ozone and emergency department (ED) visits for cellulitis. All ED visits for cellulitis in Edmonton, Canada, in the period April 1992–March 2002 (N = 69,547) were examined. Case-crossover design was applied to estimate odds ratio (OR, and 95% confidence interval) per one interquartile range (IQR) increase in ozone concentration (IQR = 14.0 ppb). Delay of ED visit relating to exposure was probed using 0- to 5-day exposure lags. For all patients in the all months (January–December) and lags 0 to 2 days, OR = 1.05 (1.02, 1.07). For male patients during the cold months (October–March): OR = 1.05 (1.02, 1.09) for lags 0 and 2 and OR = 1.06 (1.02, 1.10) for lag 3. For female patients in the warm months (April–September): OR = 1.12 (1.06, 1.18) for lags 1 and 2. Cellulitis developing on uncovered (more exposed) skin was analyzed separately, observed effects being stronger. Cellulitis may be associated with exposure to ambient ground level ozone; the exposure may facilitate cellulitis infection and aggravate acute symptoms.

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Ambient air pollution and weather conditions may affect the number of daily emergency department (ED) visits for skin bacterial infections. The aim of this study was to assess the potential relationship between the odds of an ED visit for cellulitis and the concentration of ambient ozone (O3). The data employed in the study covered ED visits for cellulitis at a Vancouver hospital in the period of January 1999 to February 2003 (1520 days, N = 9,857). A conditional logistic regression model was built to estimate odds ratios (OR) and their 95% confidence intervals (95% CI). The model was adjusted for temperature and humidity. The results are reported for one interquartile range (IQR) of ozone concentrations (IQR = 10.9 ppb). An increase by one IQR in daily ozone concentrations lagged by 3 days was significantly associated with an increase in the odds of ED visit for cellulites: among male patients OR=1.06 (95% CI: 1.01-1.13) and among female patients in the warm period (April-September) OR=1.20 (95% CI: 1.06-1.48). Patients aged 50 or less showed increased odds. Some cases of cellulitis may be associated with exposure to ambient ground-level ozone