Skip to content

Smoking Cessation Health Center

Font Size

Description of the Evidence

    continued...

    Interventions Associated With Increased Risk of Lung Cancer

    Beta-carotene supplementation in smokers

    Results of the National Cancer Institute (NCI) Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) trial were first published in 1994.[55] This trial included 29,133 Finnish male chronic smokers aged 50 to 69 years in a 2 x 2 factorial design of alpha-tocopherol (50 mg/day) and beta-carotene (20 mg/day). Subjects were randomly assigned to one of the following four groups for 5 to 8 years: beta-carotene alone, alpha-tocopherol alone, beta-carotene plus alpha-tocopherol, or placebo. Subjects receiving beta-carotene (alone or with alpha-tocopherol) had a higher incidence of lung cancer (RR = 1.18; 95% CI, 1.03–1.36) and higher total mortality (RR = 1.08; 95% CI, 1.01–1.16). This effect appeared to be associated with heavier smoking (one or more packs/day) and alcohol intake (at least one drink/day).[56] Supplementation with alpha-tocopherol produced no overall effect on lung cancer (RR = 0.99; 95% CI, 0.87–1.13).

    In 1996, the results of the U.S. Beta-Carotene and Retinol Efficacy Trial (CARET) were published.[57] This multicenter trial involved 18,314 smokers, former smokers, and asbestos-exposed workers who were randomly assigned to beta-carotene (at a higher dose than the ATBC trial, 30 mg/day) plus retinyl palmitate (25,000 IU/day) or placebo. The primary endpoint was lung cancer incidence. The trial was terminated early by the Data Monitoring Committee and NCI because its results confirmed the ATBC finding of a harmful effect of beta-carotene over that of placebo, which increased lung cancer incidence (RR = 1.28; 95% CI, 1.04–1.57) and total mortality (RR = 1.17; 95% CI, 1.03–1.33). In a follow-up study of CARET participants after the intervention discontinued, these effects attenuated for a period of time. After 6 years of postintervention follow-up, the postintervention RR for lung cancer incidence was 1.12 (95% CI, 0.97–1.31) and for total mortality was 1.08 (95% CI, 0.99–1.71). During the postintervention phase a larger RR among women, rather than men, emerged for both outcomes in subgroup analyses; the reason for this observation, if reliable, is not known.[58]

    1|2|3|4|5|6|7|8|9|10|11

    Today on WebMD

    hands breaking a cigarette
    Is quitting cold turkey an effective method?
    ashtray
    14 tips to get you through the first hard days.
     
    smoking man
    Surprising impacts of tobacco on the body.
    cigarette smoke
    What happens when you kick the habit?
     

    Filtered cigarettes
    ARTICLE
    an array of e cigarettes
    ARTICLE
     
    human heart
    ARTICLE
    Woman experiencing withdrawal symptoms
    ARTICLE
     

    man smoking cigarette
    ARTICLE
    no smoking sign
    VIDEO
     
    Woman ashing cigarette in ashtray
    ARTICLE
    chain watch
    ARTICLE