Relationship between early product substitution and harm reduction in an ENDS switching trial for adults who smoke.
When heavy smokers (>16 cigarettes/day) used e-cigarettes early in a trial, they were more likely to reduce smoking and lower harmful chemical exposure within weeks. However, lighter smokers (<7 cigarettes/day) who switched to e-cigarettes actually had worse outcomes and were more likely to use both products simultaneously.
Relevance to India: None stated.