To analyze baseline data from the Ginkgo Evaluation of Memory (GEM) study, in which information was collected on the use of all dietary supplements.
Cross-sectional regression analysis.
GEM study sites in California, Maryland, North Carolina, and Pennsylvania.
The GEM study enrolled 3,072 ambulatory individuals aged 75 and older between September 2000 and June 2002.
Self-reported use of dietary supplements and use identified through bottles brought to the clinic.
Respectively, 59.4%, 66.6%, and 27.4% of the GEM study cohort used a multivitamin, at least one individual vitamin or mineral supplement, and some type of nonvitamin/nonmineral dietary supplement (NVNMDS). In logistic regression models, multivitamin use was associated with female sex, a higher income, a higher modified Mini-Mental State Examination score, difficulty with mobility, and asthma history; use of any other vitamin or mineral was associated with female sex, white race, nonsmoking, more years of schooling, difficulty walking, a history of osteoporosis, and reading health and senior magazines; and NVNMDS use was associated with residing in California, having difficulties with muscle strength, and reading health and senior magazines.
There were substantial differences between individuals who used vitamins and minerals and those who used NVNMDS. These data require that trial investigators pay close attention to participant use of off-protocol dietary supplements. In addition, these findings may help identify elderly individuals likely to combine NVNMDS and prescription drugs.