Research, carried out by Krishna Poudel and colleagues, has found positive linear relationships between inflammation and the intensity, duration, and pack-years of smoking in HIV-positive people.
Poudel says the study's findings suggest that people living with HIV would benefit not just from quitting smoking but from smoking less. He also points out that a high level of inflammation is associated with a greater risk of disease and death in HIV-positive people.
"While it is important to support and encourage people living with HIV to quit smoking ultimately, it is also important to suggest they reduce the frequency of smoking until they can fully quit. That would also help their health status by reducing inflammation," he adds.
For the study, the research team interviewed 284 participants and collected information on their smoking, medical history, if they were receiving HAART, and other relevant details.
Participants were questioned on how many cigarettes they smoked per day (intensity) and for how many years (duration). Lifetime smoking exposure was converted in pack-years - by multiplying the number of packs smoked daily by the number of years the person has smoked.
The serum C-reactive protein (CRP), a pro-inflammatory biomarker, and other strong predictors of inflammation were then measured in the participants.
"We adjusted for zinc levels and hepatitis C. We adjusted for HAART status and CD4 cell counts. We adjusted for depression and the history of injected drug use," Poudel says. "We adjusted a total of 16 HIV-related symptoms, as well."
A positive relationship between smoking and inflammation was found in each dose-response category, but Poudel cautions that the study's design cannot determine causality.
Findings showed that a substantially higher proportion of participants with high intensity of smoking had high CRP concentrations than those with low intensity of smoking. Similarly, participants with longer smoking duration and greater pack-years were more likely to have high CRP levels than with shorter smoking duration and fewer pack-years.
Poudel says that it is crucial to develop effective smoking reduction and cessation programs for HIV-positive people in low and middle-income countries, where education and support are rarely available, Poudel says.
"Many HIV-positive people in low- and middle-income countries are willing to quit smoking and need support," Poudel says. "Our findings highlight an urgent need for providing smoking cessation support to HIV-positive people. While supporting HIV-positive people for quitting smoking is a critical public health priority, HIV care providers should encourage their patients at least to reduce the frequency of smoking, as this would be a positive step toward ultimately quitting smoking."