Passive smoking and atherosclerosis - IESC/UFRJ

Crude and adjusted estimates of the differences in mean carotid wall thickness in never
active smokers according to exposure to environmental tobacco smoke are shown in table 2.
Table 2. Differences in mean carotid wall thickness (mm) between never smokers exposed and
those unexposed to environmental tobacco smoke, unadjusted and adjusted for combinations of
selected factors in participants of the ARIC study baseline visit, excluding persons with
prevalent clinical cardiovascular disease¤
Difference in mean carotid
wall thickness (mm)
between never smokers
exposed and those
Adjusted for:
unexposed to ETS
(p-value)
No factors (crude) 0.012§
Age, race and gender
Age, race, gender plus life style factors (education, physical
activity, fat intake, alcohol intake, body mass index)
Age, race, gender, life style factors plus diabetes, hypertension
and low density lipoprotein cholesterol
¤ Myocardial infarction, angina pectoris, stroke, intermittent claudication
Environmental tobacco smoke
§ From table 1 (0.705 – 0.693 = 0.012)
0.019 (p0.001)
0.018 (p=0.003)
0.016 (p=0.001)
(12) Why is it important to examine the association between passive smoking and
carotid wall thickness adjusting for different combinations of risk factors (as
opposed to using a single model in which all potential confounders are
simultaneously adjusted)? What is the reason why the adjusted values are
larger than the unadjusted ones?
(13) What is the main shortcoming of assessing environmental tobacco smoke as a
dichotomous variable, as done in tables 1 and 2, and Figure 3?
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