People with HIV in Denmark who smoke greatly underestimate
the impact of smoking on life expectancy, a study of perceptions of life
expectancy published this month in the Journal of Acquired Immune Deficiency
Syndromes
shows.

Current smokers living with HIV, asked to estimate their
life expectancy, anticipated their life expectancy to be 3.65 years lower than
people with HIV who had never smoked. However, epidemiological research carried out in Denmark
indicates that smoking reduces life expectancy by twelve years in people living
with HIV.

In comparison, the overall estimation of life expectancy by
people living with HIV was accurate. Danish
research estimates that HIV infection will reduce life expectancy by five years

compared to the general population. People living with HIV perceived their life
expectancy to be almost four-and-a-half years shorter (4.26 years) than
people in the general population asked to estimate their life expectancy.

The study was carried out by researchers at the University
of Copenhagen who have previously investigated changes in life expectancy in
people living with HIV resulting from successful antiretroviral treatment.
Using Denmark’s national cohort of people receiving HIV care, other researchers
have looked at the impact of smoking on life expectancy in people living with
HIV.

In this study, the University of Copenhagen researchers asked
a cohort of 937 people living with HIV and 6147 age-matched controls from the
general population what age they expected to live to, and analysed responses
based on demographic and behavioural data gathered as part of larger cohort
studies.

The median age of participants was 51 years for people
living with HIV and 53 years for the general population. The cohort was 88%
male. Thirty per cent of people living with HIV were current smokers compared
to 14% of the general population sample, and 35% of people living with HIV were
former smokers compared to 38% of the general population.

People living with HIV expected to live to the age of 80.5
on average, while people in the general population expected to live to the age of
85.2 years (p0.0001).

This differential is remarkably close to the
difference in life expectancy estimated
in one national cohort study carried out in Denmark
, which projected a
reduction of 5.1 years in life expectancy compared to the general population
for people with HIV taking effective antiretroviral therapy. However, another
study which looked at people living with HIV aged 50 and over
, found that
life expectancy for this group was almost nine years shorter than for the
general population.

When asked about the effects of smoking, people living with
HIV who smoked estimated that smoking would reduce life expectancy by 3.65
years and general population respondents estimated that it would reduce life
expectancy by 4.36 years. Smokers with a longer history of smoking were likely
to estimate that smoking had a greater negative impact on life expectancy, so
that for every ten years of smoking 20 cigarettes a day, they cut their
estimate of life expectancy by 0.69 years.

Factors related to HIV disease such as current CD4 count,
viral load, previous AIDS diagnosis or hepatitis C did not affect perceptions
of life expectancy among people living with HIV.

Multivariate analysis found that male sex and higher alcohol
consumption were each independently associated with modestly lower
self-perceived life expectancy. No education after high school was associated
with a 1.76-year reduction in estimated life expectancy. HIV was associated
with a 4.26-year reduction in estimated life expectancy.

The investigators speculate that the focus on HIV infection,
both by health care providers and by people living with HIV, has shifted
attention away from the harmful effects of smoking.

“Disseminating knowledge
about the harmful effects of smoking is a perquisite for an individual to make
behavioural changes, and this study emphasizes the need for clinicians to
communicate this knowledge to PLWH,” the study authors conclude.