Particulate Air Pollution, Oxidative Stress Genes, and Heart Rate Variability in an Elderly Cohort

• Published in: Environmental health perspectives 2007-11, Vol.115 (11), p.1617-1622
• Main Authors: Teresa Chahine, Baccarelli, Andrea, Litonjua, Augusto, Wright, Robert O., Suh, Helen, Gold, Diane R., Sparrow, David, Pantel Vokonas, Schwartz, Joel
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Air Pollutants - adverse effects; Air pollution; Air Pollution - adverse effects; Alleles; Cardiovascular diseases; Cohort Studies; Environmental health; Genetic Variation; Genotypes; Glutathione Transferase - genetics; Health aspects; Heart rate; Heart Rate - physiology; Heme Oxygenase-1 - genetics; Humans; Male; Microsatellite Repeats - genetics; Microsatellites; Older adults; Oxidative stress; Oxidative Stress - genetics; Particle interactions; Particulate matter; Particulate Matter - adverse effects; Patient outcomes; Polymorphism, Genetic; Risk factors
• ISSN: 0091-6765; 1552-9924
• DOI: 10.1289/ehp.10318

Background and objectives: We have previously shown that reduced defenses against oxidative stress due to glutathione S-transferase M1 (GSTM1) deletion modify the effects of PM2.5(fine-particulate air pollution of $< 2.5 \mum$ in aerodynamic diameter) on heart rate variability (HRV) in a cross-sectional analysis of the Normative Aging Study, an elderly cohort. We have extended this to include a longitudinal analysis with more subjects and examination of the GT short tandem repeat polymorphism in the heme oxygenase-1 (HMOX-1) promoter. Methods: HRV measurements were taken on 539 subjects. Linear mixed effects models were fit for the logarithm of HRV metrics-including standard deviation of normal-to-normal intervals (SDNN), high frequency (HF), and low frequency (LF)-and PM2.5concentrations in the 48 hr preceding HRV measurement, controlling for confounders and a random subject effect. Results: PM2.5was significantly associated with SDNN (p = 0.04) and HF (p = 0.03) in all subjects. There was no association in subjects with GSTM1, whereas there was a significant association with SDNN, HF, and LF in subjects with the deletion. Similarly, there was no association with any HRV measure in subjects with the short repeat variant of HMOX-1, and significant associations in subjects with any long repeat. We found a significant three-way interaction of PM2.5with GSTM1 and HMOX-1 determining SDNN (p = 0.008), HF (p = 0.01) and LF (p = 0.04). In subjects with the GSTM1 deletion and the HMOX-1 long repeat, SDNN decreased by 13% [95% confidence interval (CI), -21% to -4%], HF decreased by 28% (95% CI, -43% to -9%), and LF decreased by 20% (95% CI, -35% to -3%) per$10 \mug/m^3$increase in PM. Conclusions: Oxidative stress is an important pathway for the autonomic effects of particles.