Pro-inflammatory cytokines moderated by visceral adiposity from a pragmatic randomized crossover trial of portable HEPA air purifiers

ABSTRACT Background : Airborne particulate matter (PM) increases the risk of cardiovascular disease. High efficiency particulate arrestance (HEPA) filtration can reduce indoor PM, but evidence is lacking as to whether HEPA filtration has an effect on pro-inflammatory cytokines. Methods : This pragmatic crossover trial randomly assigned participants to 30 days of HEPA or sham filtration, followed by a 30-day washout, and then 30 days of the alternative. Concentrations of interleukin-1β (IL-1β), interleukin 6 (IL-6), and high-sensitivity C-reactive protein (hsCRP) were measured in quality-controlled peripheral blood plasma samples using ultra-sensitive assays. Linear mixed models compared HEPA to sham filtration. The moderating effect of visceral adipose tissue (VAT) was assessed using a dichotomized A Body Shape Index (ABSI) z-score and other measures of adiposity. Results : Among 116 participants, mean age was 41.5 years, 58.6% were female, and 72.4% were non-Hispanic White. No overall difference in mean IL-1b concentration was observed between HEPA and sham filtration. However, VAT significantly moderated the results (test for interaction P = 0.001). Among participants with excessive VAT (ABSI z-score > +0.229, N = 12), HEPA filtration significantly reduced mean IL-1b concentration by 22.8% compared with sham filtration (0.138 versus 0.179 pg/mL, P < 0.001). No reduction was observed among participants with healthy VAT. Similar non-significant patterns were observed for IL-6, but little effect for hsCRP. Other measures of adiposity, including BMI, were less effective or did not moderate the results. Conclusions : VAT moderated inflammatory responses to HEPA filtration, with a significant reduction in IL-1β among participants with excessive VAT.