Incidence of Emergency Department Visits and Hospitalizations for Asthma Exacerbations during the Lunar Month in Singapore

Background:   There have been anecdotal observations that there is a higher incidence of emergency visits and hospitalizations for asthma exacerbations during the lunar months in Singapore. This is postulated to be due increased outdoor air pollution during these months secondary to cultural practices of incense and joss paper burning. Incense burning is known to release particulate matter into the environment. This increases the risk of acute irritative symptoms as well as the prevalence of chronic respiratory symptoms^1,2.

Methods:     Data of emergency visits and hospitalizations for asthma exacerbations between January 2005 and December 2012 was collected from the Singapore National Asthma Programme database. This included data from the seven main government restructured hospitals in Singapore. Linear regression was performed using SPSS 22.0 to compare the significance of asthma exacerbations during the weeks of the lunar month compared to weeks of non-lunar months between 2005 and 2012.

Results:     Results showed that there was a significant difference between lunar weeks and non-lunar weeks for the years 2005 and 2011. For 2005, the lunar weeks had significantly increased number of emergency visits and hospitalizations for asthma exacerbations (p= 0.028). However, in 2011 it was noted that the incidence was significantly reduced during the lunar weeks (p= 0.03). A combined analysis of all eight years also did not show any significant increase during the lunar weeks.

Conclusion:     There is no significant increase in the incidence of emergency visits and hospitalizations for asthma exacerbations during the lunar months in Singapore.

References:     1)    Incense smoke: clinical, structural and molecular effects on airway disease. Ta-Chang Lin, Guha Krishnaswamy, David S Chi. Clinical and Molecular Allergy 2008, 6:3                                                                                          2)    Mechanism of asthmatic exacerbation by ambient air pollution particles. Ghio AJ. Expert Rev Respir Med. 2008 Feb;2(1):109-18.