Are People With a History of Disease More Susceptible to a Short-term Exposure to Asian Dust?: A Case-Crossover Study Among the Elderly in Japan.

Abstract

Factors influencing the susceptibility of the elderly to the adverse health effects of short-term exposure to desert dust have yet to be explored. We aimed to identify the disease histories that increase the susceptibility of the elderly to disease onset induced by dust events. We used a time-stratified case-crossover design using data on 17,874 elderly residents (≥65 years) of Okayama, Japan, who were transported to hospital emergency rooms because of cardiovascular and respiratory diseases between 2006 and 2010. We used conditional logistic models to calculate the odds ratios (ORs) per interquartile increase of Asian dust. We then conducted stratified analyses based on patients with or without a history of chronic disease. Dust concentration was associated with a higher risk of cardiovascular (3-day lag), cerebrovascular (same day), and respiratory (3-day lag) disease onset. Patients with a history of respiratory disease had a higher risk of cardiovascular (OR: 1.09 [95% confidence interval (CI) = 1.00, 1.19] vs. 0.99 [0.97, 1.01]; P for interaction = 0.03) or cerebrovascular (1.15 [1.01, 1.31] vs. 0.99 [0.97, 1.01]; P = 0.02) disease onset (2-day lag) than those without. Patients with diabetes also had a higher risk of cerebrovascular disease onset (1.09 [1.00, 1.19] vs. 0.99 [0.97, 1.01]; P = 0.05) (2-day lag). In contrast, patients with a history of cerebrovascular disease had a lower risk of respiratory disease. People with a history of respiratory disease or diabetes might have a greater susceptibility to cardiovascular disease from Asian dust and would therefore benefit from proactive interventions during desert dust events.