Abstract
Introduction
Asian dust (AD) is one of the health care problems because AD increases risk for mortality, respiratory, and cardiovascular disease. Previous animal studies showed that particulate matter from AD induced oxidative stress and systemic inflammation, increased blood pressure and heart rate, and decreased cardiac contraction. However, few reports show association of AD with increased blood pressure in human healthy subjects.
Purpose
The aim of this study was to investigate effects of AD on blood pressure and blood cell counts in human.
Methods
Using generalized linear models, we estimated the association between short-term exposure to AD and systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR) and white blood cell (WBC) count in 296,168 participants aged 20 and older (men n=168,579, 56.9%) who underwent medical check-ups and had no anti-hypertensive agents between April 2005 and March 2015 in a health check-up center in Japan. AD days were the days on which AD events occurred, which were defined as decreased visibility (<10km) due to AD monitored by local meteorological observatory. Propensity score matching analysis was performed to reduce the effects of possible confounders such as age, sex, mean temperature, humidity. In multivariable generalized linear models, data of other air pollutant such as SO2, NO2, Ox or suspended particulate matter was used as covariate.
Results
During study period, 61 AD days were observed, and there were 4,670 participants undergoing medical check-ups on AD days. In the propensity score matched population (n=4,670, each), short-term exposure to AD was significantly associated with an increased risk of higher SBP, DBP, HR, or WBC count [β=1.303, 95% confidence interval (CI) 0.577 to 2.029 for SBP, β=0.630, 95% CI 0.122 to 1.138 for DBP, β=0.987, 95% CI 0.410 to 1.563 for HR, β=150.0, 95% CI 64.9 to 235.1 for WBC]. These significant associations were also observed in two-pollutant models. In subgroup analysis according to age, AD exposure had greater impact on SBP, DBP, and HR in younger people (20 to 40 years old), but WBC count in middle-high age (51 years and older).
GLM analysis according to age category
Conclusions
The present study showed that short-term exposure to AD was associated with higher SBP, DBP, HR and WBC count. Short-term exposure to AD may exacerbate sympathetic nervous system for the young and immune system for the elderly.