Associations between ambient air pollutants and clonal hematopoiesis of indeterminate potential (CHIP).

Background Clonal hematopoiesis of indeterminate potential (CHIP) is an age-related somatic mutation associated with incident hematologic cancer. Environmental stressors which, like air pollution, generate oxidative stress at the cellular level, may induce somatic mutations and some mutations may provide a selection advantage for persistence and expansion of specific clones. Materials and Methods We used data from the Multi-Ethnic Study of Atherosclerosis (MESA) N=4,379 and the Women's Health Initiative (WHI) N=7,701 to estimate cross-sectional associations between annual average air pollution concentrations at participant address the year before blood draw using validated spatiotemporal models. We used covariate-adjusted logistic regression to estimate risk of CHIP per interquartile range increases in PM2.5 (4 ug/m3) and NO2 (10 ppb) as odds ratios (95% confidence intervals). Results Prevalence of CHIP at blood draw (variant allele fraction > 2%) was 4.4% and 8.7% in MESA and WHI, respectively. The most common CHIP driver mutation was in DNMT3A. Neither pollutant was associated with CHIP: ORMESA PM2.5=1.00 (0.68-1.45), ORMESA NO2=1.05 (0.69-1.61), ORWHI PM2.5=0.97 (0.86-1.09), ORWHI NO2=0.98 (0.88-1.10); or with DNMT3A-driven CHIP. Conclusions We did not find evidence that air pollution contributes to CHIP prevalence in two large observational cohorts. Impact This is the first study to estimate associations between air pollution and CHIP.