Particulate matter (PM10) as a newly identified environmental risk factor for acute gout flares: A time-series study

ObjectivesThis study aimed to investigate the effect of short-term exposure to ambient particulate matter less than 10 μm in diameter (PM₁₀) on occurrence of acute gout flares in the general population and identify susceptible groups accordingly.MethodsThe data of emergency department (ED) cases with acute gout flare in Incheon city, Korea between January 1st 2008 and December 31st 2015 were collected from the National Health Insurance Service claims data. The levels of PM₁₀ and meterological measurements were provided by the Ministry of Environment and the National Meterological Office, respectively. To estimate the risk of daily ED visits due to acute gout flare, these time-series data set were analyzed using generalized additive models with Poisson distribution, including daily average PM₁₀ level, temperature, relative humidity, day of the week, national holiday, season, and date.ResultsThe risk of daily ED visits for acute gout flares per interquartile range increment of the average daily PM₁₀ levels significantly increased in the cumulative lag 0–7 model (relative risk, 1.018; 95% confidence interval, 1.008–1.027, P < 0.001). In particular, men aged ≥ 40 years and those with a history of diabetes mellitus or gout were significantly at a high risk of acute gout flares by subgroup analysis.ConclusionsOur time-series study demonstrated a modest, but significant effect of short-term exposure to PM₁₀ on ED visits for acute gout flares. Ambient PM₁₀ may be a newly identified environmental risk factor for acute gout flares.