Passive smoking and atherosclerosis - IESC/UFRJ

The relationship of reported number of hours of environmental tobacco smoking (ETS)
exposure to carotid wall thickness has been also assessed in ARIC. Using the authors’ own
words, the results (not shown in a table) were as follows: “For the 885 men with ETS exposure,
after controlling for age and race, there was an increase in IMT of 0.00792 mm per 10 hours of
weekly ETS exposure, a relationship that proved statistically significant. Despite a larger
sample of ETS women (n=2340), the increase in IMT per 10 hours of ETS exposure was only
0.0011 mm, a difference that proved statistically insignificant (p=0.43).”
(14) In the absence of any other data in the report, can you critically assess whether
there is indeed a linear dose-response relationship in men? Why?
(15) Assuming that these estimates of wall thickness increases are accurate and
precise, what term would you use to describe the gender difference? What are
some possible reasons for this difference?
In one of the four communities included in the ARIC study, Washington County,
Maryland (the Johns Hopkins site), the sampling frame used to select the ARIC cohort was
based on current Motor Vehicle Administration data, supplemented by a private census
conducted iun 1975 by the Johns Hopkins Training Center for Public Health Research.
About 2,884 of the 4,023 individuals who participated in the Washington County ARIC
baseline examination conducted in 1987-89 could be identified in the 1975 census, which
collected information on smoking in the household (Figure 4). Of these persons, data on both
smoking in 1975 and carotid wall thickness in 1987-89 were available for 2,073 (about 51% of
the total ARIC Washington County cohort). These 2,073 Washington County ARIC cohort
participants comprised the study group used by Diez-Roux et al to examine the relationship of
both active and passive smoking in 1975 to carotid wall thickness measured in the ARIC
baseline visit approximately 12 to 14 years later (Figure 5) (Preventive Medicine
1995;24:48-55).
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