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

Abstract

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.

Keywords:

• Methyl Bromide
• pesticide air toxicants
• Central and Southern California
• asthma ED visits

Acknowledgment

We would like to thank the California's Office of Statewide Health Planning and Development (OSHPD) for providing us with the data; and, those who helped us conducting this research.

Compliance with ethical standards

Ethics approval and consent to participate

The study was approved by the State of California Committee for the Protection of Human Subjects. The data used in this analysis does not contain any personal identifiable information. Informed consent was not required because data were anonymous. Additional safeguards included physical and electronic barriers to data access and encryption.

Consent for publication

Not Applicable

Disclosure statement

The authors declare that they have no conflict of interest.

Financial disclosure

The authors have no financial relationships relevant to this article to disclose.