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Thursday, January 26, 2006Blacks are much more likely than whites to get lung cancer from smoking cigarettes, according to a large study that provides significant new evidence in the debate over whether race plays a critical role in health. The eight-year study of more than 183,000 people found that blacks and Hawaiians are about 55 percent more likely than whites to develop lung cancer from light to moderate smoking. Japanese Americans and Latinos are about 50 percent less likely than whites, the researchers found. The study isn't perfect. The groups were not well controlled to match one another in terms of social factors such as education and years of smoking, but the differences in rates of lung cancer were striking. African-American and Hawaiian men had an incidence of lung cancer of 264/100,000 compared to 79/100,000 for Hispanic men. (White men had a rate of 158/100,000 and Japanese-American men had one of 121/100,000) Rates were lower across the board for women of all races, suggesting that something in the genes may, indeed, be responsible for the difference. The authors offer some speculation: Variation in the metabolism of nicotine among different ethnic and racial populations may underlie differences in smoking behavior (i.e., the depth and frequency of inhalation) and, thus, the uptake of carcinogens. Blacks have higher cotinine levels than white or Hispanic smokers after having smoked the same number of cigarettes. Blacks have also been reported to inhale more nicotine per cigarette smoked than whites and perhaps therefore have increased exposure to tobacco carcinogens, which may account in part for their high rates of lung cancer, despite a low number of cigarettes smoked per day. Greater dietary intake of fruit and vegetables has been associated with a reduced risk of lung cancer.20,21 There were considerable dietary differences among the ethnic and racial populations in our study; however, adjustment for mean daily fruit and vegetable intake among these groups could not explain the strong differences in risk among the populations. The level of education was related to risk, with the highest risk among those with less than eight years of schooling. Education is very likely a surrogate variable for other important exposures, but what these are and whether they are distributed disproportionately in the observed high-risk groups of African Americans and Native Hawaiians are not clear. Our findings are unlikely to be explained by differences in socioeconomic status, since over 50 percent of the African Americans in the Multiethnic Cohort Study had some college education, as compared with only 20 to 30 percent of Latinos. Another explanation for the increased risks among African Americans and Native Hawaiians at lower levels of smoking is that they are constitutionally more susceptible to the effects of tobacco carcinogens. Our data suggest that these differences may be most relevant at lower levels of smoking, perhaps because, at high levels (more than 30 cigarettes per day), metabolic or other relevant pathways become saturated. Inflammation or other pathophysiological processes may also differ between populations and influence susceptibility to lung cancer. Further research is needed to understand the underlying mechanisms. Now the next question. Will the public health police try to ban cigarette sales based on race? Of course not! That would not be P.C. posted by Sydney on 1/26/2006 07:44:00 AM 0 comments 0 Comments: |
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