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DM Torre, N-Y Wang,
LA Meoni, DE Ford, MJ Klag. Division of General Internal Medicine,
The Johns Hopkins Medical Institutions.
Background: Physicians in the U.S. have been reported to have
lower mortality than the general population. Smoking is strongly related
to most health outcomes. However the contribution of smoking behavior
to mortality benefits in this group has not been investigated.
Methods: We compared the mortality experience of a cohort of
1,213 white male medical students, graduating classes 1948-64, to
the U.S. white male population using age-race-sex and calendar time
specific death rates from U.S. vital statistics. We calculated all
cause and specific cause mortality compared to the general population,
stratifying by smoking status at baseline and lifetime smoking. Mortality
through 1998 was assessed by annual questionnaires, contacting family
members and co-workers, scanning obituaries and National Death Index
searches. Vital status was known for > 99% of the cohort.
Results: The average age was 26, average follow-up 40 years
and mean age at death 58 years. During 48,589 person-years of follow-up,
195 deaths occurred. When smoking from baseline to 1993 was considered,
all cause mortality in men compared to the general population was
74% lower for lifelong nonsmokers (SMR 0.26, 95% CI 0.19-0.36), intermediate
for those who quit smoking during follow-up (SMR 0.38, 95% CI 0.31-0.47),
and high for lifelong smokers (SMR 1.33, 95% CI 0.92-1.86). Mortality
from cardiovascular disease was 86% lower than expected for lifelong
non-smokers (SMR 0.14, 95% CI 0.06-0.26) and 46% lower than expected
for lifelong smokers (SMR 0.54, 95% CI 0.20-1.18). Risk of dying from
lung cancer was 93% lower than expected for those who never smoked
(SMR 0.07, 95% CI 0.00-0.37), greater that the general population
for lifelong smokers (SMR 1.92, 95%CI 0.62-4.49), and intermediate
for intermittent smokers (SMR 0.13, 95% CI 0.01-0.48). The risk of
dying from suicide compared to the general population was higher among
baseline smokers (SMR 2.25, 95% CI 0.16-3.92) and lifelong smokers
(SMR 8.60, 95% CI 3.14-18.72).
Conclusions: These results demonstrate the substantial health
benefits associated with low rates of smoking among physicians, compared
to the general population.
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