SAN FRANCISCO -- Vitamin supplements do not protect against lung cancer and vitamin E may even elevate risk slightly for some patients, according to researchers.
SAN FRANCISCO, May 23 -- Vitamin supplements do not protect against lung cancer and vitamin E may even elevate risk slightly for some patients, according to researchers.
Multivitamins, vitamin C, and folate did not decrease lung cancer risk even at high intake levels; vitamin E increased relative risk 7% for each 100 mg/day increase over 10 years in a cohort study, found Chris Slatore, M.D., of the University of Washington in Seattle, and colleagues.
"We've known for a long time that fruits and vegetables protect against lung cancer," he said at the American Thoracic Society meeting here. "It's hard to get people to change their diet. The hope was that it would be easier to get them to take a pill."
One study stemming from this hope was the large Beta-Carotene and Retinol Efficacy Trial (CARET). When it found beta-carotene and retinol supplements increased lung cancer risk, particularly among smokers, researchers started looking more closely at the relationship, Dr. Slatore said.
So, he and his colleagues undertook the VITamins And Lifestyle (VITAL) study to look at supplements and various types of cancer, including prostate, breast cancer, and lung cancer.
Dr. Slatore and colleagues analyzed lung cancer specific outcomes for this cohort of 77,721 men and women aged 50 to 76 living in Washington state.
Participants completed a 24-page questionnaire on type, dose, and duration of vitamin supplement use over the prior 10 years. They were monitored for incident lung cancer over about four years using the Seattle-Puget Sound Surveillance, Epidemiology and End Results (SEER) cancer registry.
The investigators found 521 cases of lung cancer.
Adjusting for risk factors including smoking, age, sex, cancer history, other lung disease, and history of lung cancer, the researchers found: