Self-determination, smoking, diet and health.

A Clinical Trial will test (1) a Self-Determination Theory (SDT) model of maintained smoking cessation and diet improvement, and (2) an SDT intervention, relative to usual care, for facilitating maintained behavior change and decreasing depressive symptoms for those who quit smoking. SDT is the only empirically derived theory which emphasizes patient autonomy and has a validated measure for each of its constructs, and this is the first trial to evaluate an SDT intervention. Adult smokers will be stratified for whether they are at National Cholesterol Education Program (1996) recommended goal for low-density lipoprotein cholesterol (LDL-C). Those with elevated LDL-C will be studied for diet improvement as well as smoking cessation. Six-month interventions involve a behavior-change counselor using principles of SDT to facilitate autonomous motivation and perceived competence for healthier behaving. Cotinine-validated smoking cessation and LDL-C-validated dietary recall of reduced fat intake, as well as depressive symptoms, will be assessed at 6 and 18 months. Structural equation modeling will test the model for both behaviors within the intervention and usual-care conditions.