Particulate air pollution and the blood

Abstract

Background-Particulate air pollution has been associated with excess deaths from, and increases in hospital admissions for, cardiovascular disease among older people. A study was undertaken to determine whether this may be a consequence of alterations in the blood, secondary to pulmonary inflammation caused by the action of fine particles on alveolar cells, by repeatedly measuring haematological factors in older people and relating them to measurements of exposure to airborne particles. Methods-One hundred and twelve individuals aged 60+ years in two UK cities provided repeated blood samples over 18 months, 108 providing the maximum of 12 samples. Estimates of individual exposure to particles of less than 10 µm diameter (PM 10 ), derived from a mathematical model based on activity diaries and comparative measurements of PM 10 at multiple sites and during a variety of activities, were made for each three day period prior to blood sampling. The relationships between blood values and estimates of both personal exposure and city centre measurements of PM 10 were investigated by analysis of covariance, adjusting for city, season, temperature, and repeated individual measurements. Results-Estimated personal exposure to PM 10 over the previous three days showed negative correlations with haemoglobin concentration, packed cell volume (PCV), and red blood cell count (p<0.001), and with platelets and factor VII levels (p<0.05). The changes in red cell indices persisted after adjustment for plasma albumin in a sample of 60 of the subjects. City centre PM 10 measurements over three days also showed negative correlations with haemoglobin and red cell count (p<0.001) and with PCV and fibrinogen (p<0.05), the relationship with haemoglobin persisting after adjustment for albumin. C reactive protein levels showed a positive association with city centre measurements of PM 10 (p<0.01). Based on a linear relationship, the estimated change in haemoglobin associated with an alteration in particle concentration of 100 µg/m 3 is estimated to have been 0.44 g/ dl (95% CI 0.62 to 0.26) for personal PM 10 and 0.73 g/dl (95% CI 1.11 to 0.36) for city centre PM 10 measurements. Conclusions-This investigation is the first to estimate personal exposures to PM 10 and to demonstrate associations between haematological indices and air pollution. The changes in haemoglobin adjusted for albumin suggest that inhalation of some component of PM 10 may cause sequestration of red cells in the circulation. We propose that an action of such particles either on lung endothelial cells or on erythrocytes themselves may be responsible for changing red cell adhesiveness. Peripheral sequestration of red cells oVers an explanation for the observed cardiovascular eVects of particulate air pollution.

Inhalation of concentrated ambient air particles exacerbates myocardial ischemia in conscious dogs.

“…Decreases in circulating red blood cell (RBC) count, hemoglobin concentration, and hematocrit have been correlated with particulate exposure in humans (Seaton et al 1999) and in dogs (Clarke et al 2000), raising the possibility that enhanced ischemia may also be attributed to a decrease in the oxygen-carrying capacity of the blood. In a hematologic study carried out on the same dogs in parallel with the current study, Savage et al (2002) found decreased RBC and platelet counts, hemoglobin concentration, and hematocrit after CAPs exposure.…”

Particulate Matters, Ulfur Dioxide, and Daily Mortality in Chongqing, China

“…Although the biologic pathways through which air pollution might increase the risk of cardiovascular mortality require further study, some cardiorespiratory pathophysiologic effects of air pollution that could increase the risk of cardiovascular disease and mortality have been observed in humans (Stieb et al 2002). Measures of ambient air pollution have been associated with poor cardiac autonomic control in the elderly (Liao et al 1999), increased heart rate (Peters et al 1999a), increased systolic blood pressure (Peters et al 1999b), increased plasma fibrinogen (Pekkanen et al 2000), increased plasma viscosity (Peters et al 1997), and possible sequestration of red cells in the circulation (Seaton et al 1999). Our results are consistent with the expectation that persons with serious respiratory or cardiovascular diseases should be those who are most sensitive to the biologic effects of air pollution.…”

Long-Term Health Effects of Particulate and Other Ambient Air Pollution: Research Can Progress Faster If We Want It To

“…The few ongoing air pollution cohort studies developed a strong focus on respiratory health, whereas short-term air pollution studies indicate that the cardiovascular system may play an important pathophysiologic role (27)(28)(29)(30). Among some of the large cohorts, data that is already available may permit investigation of whether genetic, societal, behavioral, and environmental factors modify the susceptibility to long-term effects of outdoor air pollution, an area with clear need for intensified research (1-3).…”