In
the July 1, 2007 issue of Clinical Infectious Diseases, researchers from
JohnsHopkinsUniversity presented results
of a study of lung cancer rates in people with HIV.
Past findings -- including those from a recent meta-analysis-- indicate that HIV positive people are at higher risk for lung cancer.
However, it is not known to what extent this increased risk is due to smoking,
which has been reported as more common
among HIV positive compared with HIV
negative people.
The
investigators assessed data from the AIDS Link to the Intravenous Experience (ALIVE) study, a prospective observation cohort of 2086 injection
drug users in Baltimore
followed since 1988. About one-quarter were HIV positive at baseline,
and 334 more seroconverted during follow-up. At study
entry, about 90% of participants smoked, with 45% consuming 20 or more cigarettes
(1 pack) per day and 10% consuming at least 40 cigarettes. Smoking, and the amount smoked, were similar in the HIV positive
and HIV negative groups.
Lung
cancer deaths were identified through linkage with the National Death Index. Cox
proportional hazards regression was used to examine the effect of HIV infection
on lung cancer risk, controlling for smoking status, drug use, and clinical variables.
Results
·
Among 2086 study participants observed for a total of 19,835 person-years,
27 lung cancer deaths were identified.
·14
of these deaths were among HIV positive persons.
·After
adjusting for potential confounding factors including smoking, HIV positive participants
had a 3.4-fold increased risk of death due to lung cancer.
·All
but 1 (96%) of the patients with lung cancer were smokers, smoking a mean of 1.2
packs per day.
·Lung
cancer mortality increased since the advent of effective combination
antiretroviral therapy compared with
the pre-HAART era (mortality rate ratio 4.7).
·After
adjusting for age, sex, smoking status, and calendar period, HIV infection was
associated with a significantly increased risk of lung cancer (hazard ratio 3.6).
·Pre-existing
lung disease, particularly non-infectious diseases and asthma, displayed trends
for increased lung cancer risk.
·Use
of illegal drugs was not associated with increased lung cancer risk.
·Among
HIV positive persons, smoking remained the major risk factor for lung cancer,
with the risk increasing by 70%-80% per additional daily pack of cigarettes.
·CD4
cell count and HIV load were not strongly associated with increased lung cancer
risk, and trends for increased risk related to use of HAART were not significant.
Conclusion
In
conclusion, the authors wrote, “HIV infection is associated with significantly
increased risk for developing lung cancer, independent of smoking status.”
07/13/07
Reference GD Kirk, C Merle, P O’Driscoll,
and others. HIV infection is associated with an
increased risk of lung cancer, independent of smoking. Clinical Infectious
Diseases 45(1): 103-110. July 1, 2007.
