Smoking Might Increase Risk of Contracting HIV, Study Says

Smoking might increase the risk of contracting HIV, according to a study published in the Aug. 21 online edition of the journal Sexually Transmitted Infections, the New York Times reports (Nagourney, New York Times, 9/26). Andrew Furber, a public health consultant at the South East Sheffield Primary Care Trust in the United Kingdom, and colleagues conducted a systematic review of studies examining tobacco smoking as a risk factor for either HIV infection or progression of the virus to AIDS. Of the six studies the researchers examined, five suggest that smoking tobacco is an independent risk factor for HIV seroconversion after adjusting for confounding factors (Furber et al., Sexually Transmitted Infections, 8/21). According to the study, smokers are between 60% and 300% more likely to contract HIV than nonsmokers (BBC News, 9/23). The researchers said they are not sure why the link exists, but they note the increasing evidence that smoking raises the risk of contracting all types of infections, possibly because it might alter the structure of the lungs or weaken the immune system. According to the researchers, tobacco use is often higher among groups at higher risk for HIV transmission, including commercial sex workers (New York Times, 9/26). Nine of 10 other studies the researchers looked at showed no evidence that tobacco smoking increased the progression of HIV to AIDS, according to the researchers (Reuters, 9/20).

Conclusions, Reaction
The researchers concluded that smoking tobacco might be an "independent risk factor for HIV infection although residual confounding is another possible explanation." They also write that smoking does not "appear to be related to progression to AIDS, although this finding may not be true in developing countries or with the longer life expectancies seen with highly active antiretroviral therapy" (Sexually Transmitted Infections, 8/21). "More research clearly needs to be done in this area," Furber said. He added, "As the tobacco market is squeezed in the developed world, the tobacco industry increasingly looks to Asia, Eastern Europe and Africa." Keith Alcorn, a senior editor at National AIDS Map, said, "The weakness of this analysis, as the authors themselves acknowledge, is that most of the studies reviewed were carried out before the widespread use of antiretroviral therapy in developed countries." According to Alcorn, a large study in 2006 of HIV-positive women in the U.S. receiving antiretroviral therapy finds that smokers had a 36% greater risk of developing an AIDS-related illness over five years of follow-up care. "Anyone living with HIV would be strongly advised by their doctor to stop smoking because of the increased risk of cardiovascular disease and the much greater risk of various smoking-related cancers for HIV-positive people, whether on treatment or not," Alcorn said (BBC News, 9/23).

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