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. 2014 Apr 30;9(4):e95297. doi: 10.1371/journal.pone.0095297

Figure 1. The modifying effects of time-since-cessation on the relation between smoking and PD.

Figure 1

The fitted excess OR model with a spline function for total smoking and effect modification by time-since-cessation. 95% confidence intervals were estimated via 100 bootstrap replications. A: The OR for different levels of total pack-years, plotted for 21 years-since-cessation. B: The OR for different levels of time-since-cessation, plotted for 15 pack-years of total smoking.