Background: Research shows an association between particulate air pollution exposure and cardiovascular morbidity and mortality, with atherosclerosis as an implied underlying mechanism. The accurate assessment of personal exposure is a major challenge in epidemiological research since it is strongly related to time-activity patterns. We investigated carotid intima-media thickness (CIMT) in association with subchronic personal exposure to black carbon (BC) in a panel of healthy adults.

Methods: Personal BC exposure of 54 participants (92.3% female; mean age 40.7 years) was measured during one average workweek as a proxy for subchronic exposure. Within this week, the CIMT of each participant was measured ultrasonographically on two separate days. The effect of personal BC exposure on CIMT was estimated using mixed models adjusted for covariates including gender, age, exposure to secondhand smoke and general health indicators.

Results: The analyses showed a strong positive association between CIMT and personally measured BC. An interquartile range (320.8 ng/m³) higher personal BC exposure was associated with a 40.7 μm (95% CI: 16.0 to 65.5 μm; p=0.0026) thicker CIMT. Each year increase in age was associated with a 5.02 μm (3.30 to 6.74; p<0.0001) thicker CIMT, suggesting that an IQR higher personal BC exposure is equivalent to 8 years of ageing.

Conclusion: Based on individually measured BC exposures in a relatively young cohort of healthy nurses, our results suggest a larger impact of BC on CIMT than reported so far for other measures of pollution, including particulate matter.