Vitamins, Minerals, and Specialty Supplements and Risk of Hematological Malignancies In the VITamins and Lifestyle (VITAL) Cohort Study

The use of vitamins and dietary supplements is a common health practice in many parts of the world, in part because of the belief that they will prevent diseases, including cancer. However, results of epidemiologic studies regarding their efficacy in reducing the risk of any cancer, particularly hematologic malignancies, are inconsistent and are mostly limited to case-control studies.

Participants were male and female members of the VITamins And Lifestyle (VITAL) cohort. Between 2000 and 2002, 64,839 men and women, aged 50 to 76 years, who lived in the region of Washington State covered by the Surveillance, Epidemiology, and End Results (SEER) registry, were recruited. Participants were excluded if they had any cancer prior to baseline other than non-melanoma skin cancer and were censored at the time of diagnosis of a non-hematologic malignancy during follow-up; after exclusions, there were 64,839 participants available for study. Incident cases of hematologic malignancies were identified through December 2008 by linkage to the SEER registry. Participants answered questions on the frequency (days/week), duration (years), and dose per day of their supplemental use of vitamins, including A, B3, B6, B12, C, D, E, multivitamin compounds, and folic acid; minerals, including calcium, selenium, iron, magnesium, chrome, and zinc during the 10 years before baseline. For the non-vitamin, non-mineral “specialty” supplements, garlic, ginseng, and fish oil, only frequency and duration were ascertained. Use of vitamin and mineral supplements was categorized into non-users and tertiles of use, such that the highest category was greater than could be achieved only by use of a common multivitamin (Centrum Silver). 10-year average use of specialty supplements was categorized into: non-user; low use, <4 days/week or <3 years; and high use, ≥4 days/week and ≥3 years. Multivariable-adjusted Cox proportional hazards models were used to estimate hazards ratios (HR) and 95% confidence intervals (95% CI) of the use of dietary supplements with the risk of total hematologic malignancies. Models were adjusted for age, sex, race/ethnicity (white/hispanic/other), education, smoking, self-rated health, physical activity, history of anemia in the year before baseline, and family history of leukemia or lymphoma.

A total of 577 case of hematological malignancies were identified including MDS [n=54], AML [n=36], myeloproliferative disorders [n=46], CLL/SLL [n=88] and other non-Hodgkin lymphomas [n=235], Hodgkin lymphomas [n=22], plasma cell disorders [n=66], mature NK/T cell neoplasms [n=17], and other entities [n=13]). None of the vitamin 10-year average intakes were associated with decreased risk of incident hematologic malignancies There was no evidence that high use of vitamins A (HR=0.79, 95% CI: 0.58–1.08; p-trend=0.28), B12 (HR=0.98, 95%CI: 0.73–1.31; p-trend=0.26), C (HR=0.97, 95% CI: 0.77–1.22; p-trend=0.99), D (HR=0.90, 95% CI: 0.62–1.31; p-trend=0.45), or folic acid (HR=1.00, 95% CI: 0.73–1.39; p-trend=0.19) was associated with the risk of blood cancer. Among specialty supplements, only high 10-year average use of garlic was significantly associated with a reduced risk of development of blood cancers (HR=0.64,95% CI: 0.42–0.98); however the association was not linear (p-trend=0.14).

We observed no reduction in the risk of incident hematologic malignancies with dietary supplement and vitamin use with the exception of garlic when used at a high amount (≥4 days/week for ≥ 3 years).

No relevant conflicts of interest to declare.