Tobacco Dependence Transition Speed & The Power of Quasi-Causality

Tobacco use is responsible for millions of deaths worldwide and is a tremendous financial burden for society. Increased understanding of the temporal development of tobacco use may indicate a more precise time window for... [ view full abstract ]

Tobacco use is responsible for millions of deaths worldwide and is a tremendous financial burden for society. Increased understanding of the temporal development of tobacco use may indicate a more precise time window for targeted intervention and prevention. Early tobacco initiation increases risk for the progression to tobacco dependence, but is associated with substantially slower transitions to dependence. Using a co-twin control (CTC) design and a sample of ~2800 twins we investigated the quasi-causal relationship between age of tobacco initiation and transition times to dependence. One limitation of the CTC design is limited power to detect potentially causal relationships and little is known regarding the most powerful technique to model these associations in twins. Therefore, we conducted a power analysis manipulating sample size and the level of quasi-causal effect on different types of CTC designs. Using the most powerful CTC method from our power analysis, we analyzed the quasi-causal effect of early initiation with slower transitions to dependence and investigated potential confounding of zygosity. Our results elucidate the relationship between early tobacco use and slower transitions to dependence and may have important implications for discordant twin research and substance use prevention programs.