TNF and asthma: The inflammatory response gene TNF (rs1800629) has been reported to modify the relationship between ozone and asthma (Yang et al. 2008) and indoor home dampness and asthma (Tsai et al. 2011); however, similar to our results, no effect modification was noted in the association between traffic-related NO2 and adult-onset asthma (Castro-Giner et al. 2009).