Natural health product use in Canada: analysis of the National Population Health Survey.

Background: The use of natural health products (NHPs) in Western countries has increased dramatically over the past two decades. Although prevalence estimates have been published in the U.S. and elsewhere, little is known about the characteristics of persons who use NHPs.

Objectives: To measure the prevalence of NHP use among adults in Canada, identify the most commonly used agents, and determine the socioeconomic, demographic, and health-related correlates of use.

Methods: NHP use by adults was assessed using the 2000-2001 National Population Health Survey (NPHS), a biennial general health survey conducted by Statistics Canada. A total of 11,424 adults completed the survey in 2000-2001. NHPs were defined as botanical and naturally-derived non-botanical products, excluding essential vitamins and minerals. Prevalence of use estimates were calculated nationally, and by age, gender, socioeconomic status, disease states, and health care practices. Multivariate logistic regression modeling was used to simultaneously assess the correlations of these variables with NHP use.

Results: The prevalence of past 2-day NHP use in Canada was 9.3% in 2000-2001. Fifty-seven percent of users also reported taking a conventional medicine in the same period. Glucosamine, echinacea, and garlic were the most frequently used products. Women reported NHP use more frequently than men (11.5% vs. 7.1%). As compared to young adults, NHP use was about 50% higher in middle-aged and older Canadians. There were no associations with either income or education level. Several disease states were associated with a high prevalence of NHP use: respondents with fibromyalgia (23.3%), inflammatory bowel disease (17.4%), and urinary incontinence (16.8%) were most likely to be NHP users. However, in the multivariate analysis, age and the use of vitamins or minerals were most predictive of NHP use, while health status variables were of less importance.

Conclusions: NHP use is an important health phenomenon in Canada. Although respondents in poor health were more likely to use NHPs, a significant proportion of healthy Canadians also reported NHP use. The use of NHPs also cut across different socioeconomic groups. Concurrent use of conventional medications was common and suggests a need for health professionals to monitor for potential interactions.