Beware the Air

Emerging evidence suggests a potential role of particulate matter air pollution (most notably particulates measuring less than 2.5 micrometers in size [PM2.5]) to trigger or worsen certain health conditions, from cardiac to respiratory disorders.  A condition that causes reduced quality of life, anxiety is a common disorder for which previous studies suggest external contributing factors.   Melinda C. Power, from Johns Hopkins University (Maryland, USA), and colleagues studied  data collected on 71, 271 women, ages 57 to 85 years, enrolled in the US Nurses’ Health Study. The team used national geographic and meteorological data to establish exposure to particulate matter (PM 2.5 and PM 2.5-10), estimating from five periods (one month, three months, six months, one year and 15 years) before assessment of anxiety. The team also calculated the distance from residence address to the nearest major road, a common indicator for traffic related air pollution exposure. Study participants completed an anxiety questionnaire that included eight self-rated questions on symptoms including fearfulness, desire for avoidance and tendency to worry was completed by each participant. After adjusting for confounding factors, data analysis revealed that approximately 15% of women experienced high anxiety symptoms. Exposure to particulate matter was linked to a higher risk of anxiety, with PM2.5 having the most significant association.  Further, women who resided 50 to 200m from a major road were more likely to have higher anxiety symptoms, as compared to those living more than 200m away.  As well, recent exposure was found to have a more significant association with anxiety, with effects the strongest following the first month of exposure.  The study authors warn that: “Exposure to fine particulate matter (PM2.5) was associated with high symptoms of anxiety, with more recent exposures potentially more relevant than more distant exposures.”