Association between TNF-α, cortisol levels, and exposure to PM10 and PM2.5: a pilot study

Purpose The most harmful atmospheric pollutant for human health is particulate matter (PM). We analyzed the correlation between short-term lag exposure to PM10 and PM2.5, salivary cortisol and TNF-α level, and methylation levels of the TNF-α promoter. Methods A pilot study including 20 subjects. Eight salivary samples for each subject at various times of the day were collected for comparing cortisol levels and TNFα detection. TNFα promoter methylation levels on salivary DNA were analyzed. Regression analyses were performed using generalized linear mixed models between the different outcomes and 4, 3, 2 and 1 day’s lag values of PM10/PM2.5.Generalized additive mixed model (GAMM) was used to evaluate any potential deviation from linearity. Results Area under the curve with respect to the ground (AUCg) showed a statistically positive association with 4-, 3-, 2-, and 1-day lag of exposure to PM10. Area under the curve with respect to the increase (AUCi) showed a statistically negative association with 4-, 3- and 1-day lag of exposure to PM10. TNFα showed statistically significant association with both exposures, PM10 and PM2.5, at 4-, 3-, 2-, and 1-day lag. Conclusions Regarding cortisol levels there is an increase of overall hormone levels but a less dynamism of the system to answer to external stressors. Increase of TNF-α may reflect increased levels of oxidative stress and inflammation due to pollution exposure.