A new study has revealed that in patients with pre-existing heart or lung disease, exposure to high levels of traffic-related air pollutants is linked to reduced heart rate variability (HRV) - a risk factor for sudden cardiac death.

The study included 30 Atlanta-area residents with lung disease (chronic obstructive pulmonary disease) or heart disease (previous myocardial infarction). Ambient levels of air pollutants in the areas where the patients lived were unrelated to HRV. However, when the patients wore 24-hour monitoring devices, their personal exposure (levels of traffic-related air pollutants-specifically, elemental carbon and nitrogen dioxide) were significantly related to reduced HRV.

In contrast, the Atlanta patients were spread out over a larger area, with differing population densities, distances from major roads, etc. The results add to recent evidence that short-term, personal exposure to traffic-related pollution is linked to decreased HRV and increased cardiac risk.

The findings of the survey were published in the Journal of Occupational and Environmental Medicine, official publication of the American College of Occupational and Environmental Medicine (ACOEM).