Applying the transtheoretical model to tobacco cessation and prevention: a review of literature.

OBJECTIVE: To comprehensively review all published, peer-reviewed research on the Transtheoretical Model (TTM) and tobacco cessation and prevention by exploring the validity of its constructs, the evidence for use of interventions based on the TTM, the description of populations using TTM constructs, and the identification of areas for further research. The three research questions answered were: "How is the validity of the TTM as applied to tobacco supported by research?" "How does the TTM describe special populations regarding tobacco use?" "What is the nature of evidence supporting the use of stage-matched tobacco interventions?" DATA SOURCE: Computer Database search (PsychInfo, Medline, Current Contents, ERIC, CINAHL-Allied Health, and Pro-Quest Nursing) and manual journal search. INCLUSION/EXCLUSION CRITERIA: All English, original, research articles on the TTM as it relates to tobacco use published in peer-reviewed journals prior to March 1, 2001, were included. Commentaries, editorials, and books were not included. DATA EXTRACTION AND SYNTHESIS: Articles were categorized as TTM construct validation, population descriptions using TTM constructs, or intervention evaluation using TTM constructs. Summary tables including study design, research rating, purpose, methods, findings, and implications were created. Articles were further divided into groups according to their purpose. Considering both the findings and research quality of each, the three research questions were addressed.
RESULTS: The 148 articles reviewed included 54 validation studies, 73 population studies, and 37 interventions (some articles fit two categories). Overall, the evidence in support of the TTM as applied to tobacco use was strong, with supportive studies being more numerous and of a better design than nonsupportive studies. Using established criteria, we rated the construct validity of the entire body of literature as good; however, notable concerns exist about the staging construct. A majority of stage-matched intervention studies provided positive results and were of a better quality than those not supportive of stage-matched interventions; thus, we rated the body of literature using stage-matched tobacco interventions as acceptable and the body of literature using non-stage-matched interventions as suggestive. Population studies indicated that TTM constructs are applicable to a wide variety of general and special populations both in and outside of the United States, although a few exceptions exist.
CONCLUSIONS: Evidence for the validity of the TTM as it applies to tobacco use is strong and growing; however, it is not conclusive. Eight different staging mechanisms were identified, raising the question of which are most valid and reliable. Interventions tailored to a smoker's stage were successful more often than nontailored interventions in promoting forward stage movement. Stage distribution is well-documented for U.S. populations; however, more research is needed for non-U.S. populations, for special populations, and on other TTM constructs.