Respiratory Changes due to Long-term Exposure to Urban Levels of Air Pollution

In: Pulmonary function

7 May 2014

Respiratory Changes due to Long-term Exposure to Urban Levels of Air PollutionAcute effects of air pollution on human health have been demonstrated by different studies, using various statistical designs and analytical approaches. Fewer studies have evaluated the longterm effects of air pollution. Two recent prospective cohort studies observed that long-term exposure to air pollution was associated with chronic health effects that were manifested by a significant increased risk of cardiopulmonary mortality. These studies were able to control for individual differences in various alternative risk factors, including age, sex, race, and cigarette smoking, and indicate the necessity of further studies to address the possible effects of long-term exposure to air pollution on health. In this context, histopathologic studies of the lungs may provide useful information not only to support the hypothesis that long-term exposure to urban levels of air pollution cause respiratory impairment, but also to characterize some of the mechanisms of pollution-induced injury. avandia online

Unfortunately, there are few reports on the histopathologic alterations secondary to long-term exposure to air pollution. Scott studied the volume of mucus-secreting glands of human airways across different smoking and air pollution conditions and suggested that ambient pollution could be an important factor in the pathogenesis of chronic bronchitis. Based on necropsy studies, it has also been suggested that young residents of the Los Angeles area have histologic evidences of damage at the distal airspace.
The aforementioned studies have support from a series of experiments performed in our laboratory in which rats were kept for prolonged periods of time in areas with different pollution backgrounds. Rats exposed long term to air pollution had inflammatory alterations of the air passages and alveolar parenchyma, mucus hypersecretion, decrease of mucociliary transport, and bronchial hyperresponsiveness. Similar findings were recently reported by other groups indicating that the hypothesis that longterm exposure to air pollution promotes respiratory damage is plausible and that more work is necessaiy to determine the real impact of pollution on the health of inhabitants of the urban large conglomerates.
The present study was designed to further evaluate potential associations between long-term exposure to air pollution and significant histologic alterations of the lungs. For this purpose, human lung samples of people who had lived in areas with different pollution backgrounds but who had died due to violent causes were taken during necroscopic examination and submitted to quantitative histopathologic studies.

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