The analysis showed that the AOR for wave 2 SRO among recent former smokers (category 3) did not differ from persistent current smokers (category 4) (χ2 (1)=1.26, p=0.26). However, long-term former smokers (category 2) showed a significantly lower AOR for wave 2 SRO than persistent current smokers (χ2 (1)=16.9, p<0.0001). These data suggest that a reduction in risk for future SRO with past smoking becomes apparent after a considerable period of abstinence. Of additional interest were the risk estimates associated with re-starting (ie, relapse) and with beginning to smoke in wave 2. Compared with persistent current smokers, the AOR for wave 2 SRO was significantly higher for both relapsers (χ2 (1) =56.00, p<0.0001) and smoking beginners in wave 2 (χ2 (1) =4.11, p=0.04). Furthermore, the AOR for wave 2 SRO was significantly higher among relapsers than beginning smokers (χ2 (1)=19.0, p<0.0001).
