Cancer in twin pairs discordant for smoking
The discordant twin pair study design is powerful to control for familial confounding. We employed this approach to investigate the associations of smoking with several cancers.
Unlike lung cancer, a causal association between smoking and other cancer sites that are associated smoking remains to be established.
In this Nordic Twin Study of Cancer, the authors employed the discordant twin pair study design to study the associations of smoking with several cancers while controlling for familial confounding. The analysis of genetically informative twin data indicates that cigarette smoking is a risk factor for multiple cancers, independent of familial confounding. The causative role of cigarette smoking in cancer is thus not limited to lung cancer but appears to extend to several other cancer types.
Cancer in twin pairs discordant for smoking: The Nordic Twin Study of Cancer
T Korhonen, J Hjelmborg, J Harris, S Clemmensen, HO Adami, J Kaprio.
International Journal of Cancer, 2022 Feb / Volume 151, Issue 1 / p. 33-43.