Effects of TRAP Exposure on Development and Persistence of Asthma and Low Lung Function in Middle Age Adults

Abstract

Background/Aim: There has been limited investigation of the association between exposure to Traffic Related Air Pollution (TRAP) and development or persistence of asthma and impaired lung function in adults. Methods: Associations between TRAP exposure and asthma (n=649), and lung function (n=573), were investigated using data from three follow-ups (mean ages of 45, 50 and 55 years) of the Tasmanian Longitudinal Health Study. TRAP exposure at residential address at the ag of 45 years was assigned using two methods: 1. Mean annual NO2 from a validated land-use regression model, and; 2. distance to the nearest major road. Multinomial logistic regression was used to model the association between TRAP exposures at age 45 years and change in both asthma status and lung function while adjusting for confounders. Low lung function was defined by FEV1 less than the 5th percentile (z-score <-1.645). Results: Among those who did not have asthma at 45 years, living <200 metres from a major road at age 45 years and NO2 exposure were associated with increased risk of new asthma at 50 and 55 years (adjusted Odds Ratio [aOR] 3.57; 95%CI 1.55, 8.25 and aOR 1.43; 95%CI 1.06, 1.93 [per IQR increase of NO2 = 2.4 ppb], respectively). Among those who had asthma at 45 years, living <200m from a major road was associated with persistent asthma from 45 to 55 years (aOR 1.79; 95%CI 1.10, 2.90). For those with a low FEV1 at 45 years, living < 200m from a major road was associated with persistent low FEV1 from 45 to 55 years (aOR 2.09; 95%CI 1.03, 4.25), a similar trend was observed with NO2 exposure. Conclusions: TRAP exposure in middle-aged adults is associated with new asthma, persistent asthma and persistently impaired lung function.