Nitrogen dioxide and asthma emergency department visits in California, USA during cold season (November to February) of 2005 to 2015: A time-stratified case-crossover analysis.

Nitrogen dioxide (NO2) is responsible for aggravating respiratory diseases, particularly asthma. The aim of this study is to investigate the association between NO2 exposure and asthma emergency department (ED) visits during the cold season (November-February) in five populated locations (Sacramento, San Francisco, Fresno, Los Angeles, and San Diego) of California from 2005 to 2015 (1320 Days). Conditional logistic regression models were used to obtain the odds ratio (OR) and 95% confidence interval (CI) associated with a 5 ppb increase in NO2 concentration for the 19,735 ED visits identified. An increase in NO2 exposure increased the odds of having asthma ED visits for the studied population. The potential effect modification by sex (female and male), race (White, Black, Hispanic, and Asian), and age (2-5, 6-18, 19-40, 41-64, and ≥65) was explored. A 5 ppb increase in the concentration of NO2 during lag 0-30 was associated with a 56% increase in the odds of having an asthma ED visit (OR = 1.560, CI: 1.428-1.703). Sex was not found to be a modifier. Asthma ED visits among all the races/ethnicities (except Asians) were associated with NO2 exposure. Whites had the highest OR 75% (OR = 1.750, CI: 1.417-2.160) at lag 0-30 in response to NO2 exposure. The association between NO2 exposure and asthma ED visits was positive among all age groups except for 19 to 40 years old; the OR was higher among 2 to 18 year old (at lag 0-30: age group 2-5 (OR = 1.699, CI: 1.399-2.062), and age group 6-18 (OR = 1.568, CI 1.348-1.825)). For stratification by location, San Diego and Fresno were found to have the highest OR, compared to the other studied locations.

Methyl-bromide and asthma emergency department visits in California, USA from 2005 to 2011.

Objective: Urban monitors of Methyl bromide (MBr), not typically near application sites, are used to investigate the impact of ambient concentrations on asthma Emergency Department (ED) visits.Methods: 4262 ED visits from August to February of 2005 to 2011 in Central and Southern California were selected from California's Office of Statewide Health Planning and Development (OSHPD). A bidirectional-symmetric case-crossover study design using conditional logistic regression model was used to obtain the odds ratio (OR) and 95% confidence interval associated with a 0.01 ppb (interquartile range) increase in MBr.Results: The population sample was comprised of 46.0% male and 53.9% females. Ethnic groups included 32.0% Non-Hispanic White, 23.5% Non-Hispanic Black, and 44.4% Hispanic. Age distribution was between 2 and 5 years old (11.6%), 6 and 18 years old (23.5%), 19 and 40 years old (29.3%), 41 and 64 years old (24.1%), and 65 or older (6.9%). There was a positive association between MBr and asthma ED visits among Non-Hispanic Blacks [OR: 1.065 (95% confidence intervals: 1.019, 1.108)] and Hispanics [OR: 1.107 (95% confidence intervals: 1.043, 1.173)], while Non-Hispanic Whites did not have an association with asthma ED visits. Positive association between MBr and asthma ED visits was found only among 6 to 18 [OR: 1.071 (95% confidence intervals: 1.016, 1.125)] years old.Conclusion: An increase in MBr concentration was found to be associated with an increase of the odds of having asthma ED visits in California among 6 to 18 years old and disproportionately affects Non-Hispanic Blacks and Hispanics over Non-Hispanic Whites.

The association between 1,3-dichloropropene and asthma emergency department visits in California, USA from 2005 to 2011: a bidirectional-symmetric case crossover study.

Objective: The ever-increasing rate of pesticide use in California farmlands is of great concern due to its potential toxicity on human health. In this study, the association between short term exposure to 1,3-dichloropropene (1,3-D) and asthma emergency department (ED) visits in central and southern California from 2005 to 2011 is investigated.Methods: 3878 ED visits were identified from 2005 to 2011 (1064 days). Conditional logistic regression models were used to obtain the odds ratio (OR) associated with 0.01 ppb increase in 1,3-D. Potential effect modification by sex, race/ethnicity (Non-Hispanic White, Non-Hispanic Black, or Hispanic), and age (2-5, 6-18, 19-40, 41-64 or ≥ 65) are investigated.Results: It was found that a 0.01 ppb increase in 1,3-D at the event day is associated with 13.5% [OR = 1.135, 95% CI: 1.123, 1.149] increase in the odds of having asthma ED visits in central and southern California during October to February of 2005 to 2011. Race had a positive association between 1,3-D and asthma ED visits among Non-Hispanic Black [OR= 1.095 95% CI: 1.035, 1.155] and Hispanic [OR= 1.121 95% CI: 1.064, 1.179]; while Non-Hispanic Whites had no association. Positive association for age was found between 1,3-D and asthma ED visits among patients 2 to 5 [OR= 1.065 95% CI: 1.020, 1.133], 6 to 18 [OR= 1.142 95% CI: 1.086, 1.196], and 19 to 40 [OR= 1.023 95% CI: 1.015, 1.073] years old.Conclusion: These findings suggest a 0.01 ppb increase in 1,3-D concentration increases the odds of having asthma ED visits.