Study Connects Multivitamin Use With Mortality Risk
Daily multivitamin users were associated with a 4% higher mortality risk compared to nonusers.
Consuming multivitamin (MV) supplements were not associated with a mortality benefit, according to research drawn from 3 cohort studies conducted by Erikka Loftfield, PhD, MPH from the National Cancer Institute, and colleagues. Researchers found the use of MV declined by 6% from 1999 to 2011. However, despite this, MV remains prevalent as 1 in 3 US adults take MV to prevent chronic disease and improve health.1,2
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The US Preventive Services Task Force (USPSTF) reviewed data in 2022 that assessed all-cause mortality in connection to taking a MV supplement. Study authors noted that the data displayed insufficient evidence of benefits when taking a MV. However, further research displayed a mix of mortality connected to the use of MVs. Researchers noted that this could be due to lifestyle impacts as most MV users reported living a healthier lifestyle that included healthier diets, more exercise, and less cigarette smoking. Additionally, researchers noted that it is unknown how the use of MV can adjust over time and impact individuals’ health. Other studies have displayed no benefit of MV use in reducing cardiovascular disease, cancer, or mortality. In contrast, another study found a lower risk of cardiovascular disease mortality among individuals that reported to take MV compared with those that did not.2
To assess the use of daily MV in connection with a lower mortality risk, researchers used data from 3 large US based cohorts that conducted repeat assessments and follow-ups on MV use in mortality outcomes. The study included data from the National Institutes of Health–AARP Diet and Health Study (NIH-AARP) cohort, the PLCO Cancer Screening Trial cohort, and the Agricultural Health Study (AHS) cohort. Among each cohort, a total of 390,124 individuals were included in the final analytic sample for the complete case and the time-varying complete-case included 234,593 of these individuals, according to study authors.2
All individuals were required to complete baseline and follow-up questionaries that assessed their MV supplement use in the past. Following the questionaries, the researchers divided the individuals into 3 categories— nonusers, non-daily users, or daily users of MV. Across all 3 cohorts, the study authors noted that the individuals were followed from baseline MV assessment until date of death, loss to follow-up, or the completion of the study, which included more than 20 years of follow-up.2
The results displayed that daily use of MV was not connected with a mortality benefit among the largely healthy group of individuals evaluated. The study authors noted that the results showed daily MV users were associated with a 4% higher mortality risk compared to nonusers.2
“Considerable evidence now shows that, apart from the aforementioned roles for vitamin supplementation, there is little health rationale for the use of multivitamin supplements. Micronutrients come most healthfully from food sources. When supplementation is required, it can often be limited to the micronutrients in question,” said study authors, in a news release.1
Limitations in the study included poorly measured or unmeasured confounders since the trial was an observational study. Along with misclassification due to memory of sporadic MV usage and selection bias. Additionally, all 3 cohorts included a majority of White individuals, which could display statistical power for subgroup analyses.2
