Skip to main content
. Author manuscript; available in PMC: 2010 Feb 16.
Published in final edited form as: N Engl J Med. 2008 May 22;358(21):2249–2258. doi: 10.1056/NEJMsa0706154

Figure 4. Association of Smoking Status Between Subjects and Their Social Contacts.

Figure 4

The figure shows the probability that a subject (an “ego”) smokes given that their social contact (an “alter”) quits smoking, for generalized estimating equation logit models of smoking on several different sub-samples of the Framingham Heart Study Social Network. The dependent variable in each model is subject smoking and independent variables include lagged subject smoking status, contact smoking status, lagged contact smoking, subject age, gender, and education, and fixed effects for each wave. Full models and equations are available in the supplement. Mean effect sizes and 95% confidence intervals calculated by simulating first difference in contact contemporaneous smoking (changing from 1 to 0) using 1,000 randomly drawn sets of estimates from coefficient covariance matrix and assuming all other variables are held at their means. “Small firm coworkers” are those where six or fewer FHS participants work at the same physical location.