High dietary intakes and blood concentrations of the micronutrients vitamin C, 13-carotene, folate, and vitamin B have been associated with a decreased risk of cardiovascular disease and/or cancer in epidemiologic studies. Identifying modifiable risk factors which influence plasma concentrations of these micronutrients could provide a means of decreasing disease risk. Cigarette smoking has been shown in numerous cross-sectional studies to be associated with lower plasma concentrations and dietary intake of these micronutrients, potentially placing smokers at increased risk for disease. However, very few studies have examined the effect of smoking cessation on intake or plasma concentrations of these micronutrients. In the proposed study, subjects in a recently-funded study of smoking cessation and cervical dysplasia progression will be utilized to study the effects of smoking cessation on these plasma micronutrients in a cost-effective manner. Subjects in the Smoking Cessation to Reduce Cervical Cancer Risk (WISH) study will be randomized to either usual care or an intensive theory-based smoking cessation intervention and followed for 18 months to assess the effect of smoking cessation on the progression of existing cervical dysplasia. In the proposed study, concentrations of vitamin C, beta-carotene, folate, and alpha-tocopherols will be measured in all 220 randomized WISH subjects at baseline, prior to the intervention, and at the first 6-month follow-up visit, following completion of the intensive portion of the smoking cessation intervention. Dietary assessment will also be conducted at the same two visits, using a food frequency questionnaire. Multiple linear regressions will be used to determine the effect of smoking cessation on plasma concentrations of these micronutrients, controlling for dietary intake and other factors. Regression analysis will also be used to determine the effect of smoking cessation on the dietary intake of these micronutrients. If smoking cessation is associated with increased plasma micronutrients as hypothesized, this would provide further justification for encouraging smokers to quit.
| Shikany, James M; Heimburger, Douglas C; Piyathilake, Chandrika J et al. (2004) Effect of folic acid fortification of foods on folate intake in female smokers with cervical dysplasia. Nutrition 20:409-14 |
