Use of vitamins, minerals and herbs: a survey of patients attending familypractice clinics

Objective: To examine the use of vitamin, mineral and herbal supplements in patients attending family practice clinics. Design: A prospective 1-year cohort study. Setting: Sixteen family practices in Calgary. Participants: One hundred and eighteen patients (more than 18 years of age) were initially interviewed; 12 patients were lost to follow-up. Main outcome measures: Number and type of supplements used, duration of use , sources of patient information, beliefs about supplement efficacy and saf ety, reporting use to physicians, costs and changes in pattern of use over 1 year. Results: Supplement use was unrelated to age, but more women (73%) used sup plements than men (44%). Relative to age, more patients younger than 50 yea rs believed supplements were safer than prescription medications (82% v. 43 %, p = 0.0005). Younger patients were less likely than those over 50 years old to have received supplement information from physicians (10% v. 37%, p = 0.0008) and were less compliant than older patients with manufacturers' r ecommended dosages (p = 0.02). Whereas 74% of those over the age of 50 year s informed their physician that they used supplements, only 30% of younger patients did so (p = 0.0006). At 1-year followup, the number of supplements taken per patient increased (p < 0.05), and there was a tendency for more patients to take supplements (61% v. 70%, p = NS). Conclusions: The majority of patients attending family practices in Calgary use vitamin, mineral or herbal supplements, and monitoring of supplement u se by health care professionals is minimal. Young patients, in particular, tend not to report their use of supplements. They also believe the suppleme nts are safer and more effective than prescription medications and obtain i nformation from nonmedical sources. Physicians should enhance patient under standing of these products and include supplement use in all medical histor ies. In particular, younger patients require more reliable information on s upplements.