Daily multivitamin use was found to have no mortality benefit in a large-scale analysis of data form 390,124 healthy U.S. adults followed for more than 20 years.

"In contrast, we found that daily multivitamin use vs nonuse was associated with 4% higher mortality risk," wrote the study investigators from the National Cancer Institute.

Data from 3 large, geographically diverse prospective studies involving generally healthy U.S. adults were reviewed: the National Institutes of Health–AARP Diet and Health Study (327,732 participants), Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (42,732 participants), and Agricultural Health Study (19,660 participants).

Participants were adults without a history of cancer or other chronic diseases, with baseline multivitamin use assessed from 1993 to 2001 and follow-up multivitamin use assessed from 1998 to 2004. The main outcome was mortality, according to the results published in JAMA Network Open.

Among the 390,124 participants (median age 61.5 years; 55.4% male), 164,762 deaths occurred during follow-up. After adjusting for factors such as race and ethnicity, education, and diet quality, the analysis showed that daily multivitamin use was not associated with a lower risk of death from any cause compared with no multivitamin use.

Multivitamin use was not associated with lower all-cause mortality risk in the first (multivariable-adjusted HR, 1.04; 95% CI, 1.02-1.07) or second (multivariable-adjusted HR, 1.04; 95% CI, 0.99-1.08) halves of follow-up.

HRs were similar for major causes of death, including cancer, heart disease, and cerebrovascular diseases, and in time-varying analyses.

"In the U.S., multivitamin use declined by 6% from 1999 to 2011 but remains popular, with nearly 1 in 3 adults reporting recent use," noted study investigators.

The researchers highlighted the need for further studies to evaluate multivitamin use and mortality risk among different populations, such as those with documented nutritional deficiencies, and to investigate the potential impact of regular multivitamin use on other health conditions associated with aging.

The authors declared having no competing interests.