Concurrent Use of Drugs and Supplements in a Community-Dwelling Population Aged 50 Years or More: Potential Benefits and Risks
The use of vitamin and mineral (VMs) and non-vitamin/non-mineral supplements (non-VMs) in the general population and the older population in developed countries has increased. When combined with drugs, their use can be associated with benefit and potential risks.
The aims of this study were to determine the extent and associated factors of the combined use of drugs and VM/non-VM supplements, and to examine the potential major drug–supplement interactions
Cross-sectional analysis of first-wave data of TILDA, The Irish Longitudinal Study on Ageing, nationally representative a cohort including 8,081 community-dwelling persons aged ≥50 years. Prevalences including 95 % confidence intervals (CI) were weighted to the population. Group differences in drug and supplement use were assessed using Pearson’s Chi-square test, and associations between concurrent drug–supplement use and covariates were assessed using logistic regression. Potential interactions between drugs and supplements were assessed using relevant sources.
Every seventh respondent (14.0 %; 95 % CI 13.1–15.0) reported regular concurrent use of drugs and supplements; 7.9 % (95 % CI 7.3–8.6) took only VMs, 3.9 % (95 % CI 3.4–4.4) took only non-VMs, and 2.2 % (95 % CI 1.8–2.6) took at least one of each concurrently with drugs. Concurrent use was more prevalent in women and in the oldest (≥75 years) group. Chronic disease, female sex, third-level education and private medical insurance were associated with an increased likelihood of use of both supplement types, whereas those classed as employed were much less likely to use any supplements. Supplements were combined with drugs in all of the commonly prescribed therapeutic groups, ranging from just under 60 % with drugs for bone diseases to 15.7 % with drugs for diabetes. Potential major drug–supplement interactions were detected in 4.5 % (95 % CI 3.4–5.8) of concurrent drug–supplement users, and were more prevalent in older respondents.
Concurrent use of drugs and supplements among those aged over 50 years in the Irish population is substantial and increases with age. There is considerable variation in usage, and the outcome of this approach is evidence of unmet need and therefore unrealised benefits among some subgroups, and of exposure to avoidable and potential serious drug interactions among others.
KeywordsRosuvastatin Food Supplement Adverse Drug Reaction Reporting Supplement Type Thyroid Hormone Replacement Therapy
The authors wish to thank the Irish Medicines Board for the pharmacovigilance data on food supplement use and to acknowledge the contribution of the TILDA participants and research staff.
This work was supported by Irish Life; the Department for Health and Children; and by The Atlantic Philanthropies. The sponsors had no role in the design and conduct of the study; collection, management, analysis and interpretation of the data; or preparation, review and approval of the manuscript.
The authors have no potential conflicts of interest that are directly relevant to the content of this study.
The presented work has not been submitted elsewhere. Preliminary results were presented at a poster session at the British Geriatric Society Spring meeting in Belfast, April 2013.
J. Peklar and K. Richardson had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: All authors.
Analysis and interpretation of data: J. Peklar, M.C. Henman, M. Kos.
Drafting of the manuscript: J. Peklar and M.C. Henman.
Statistical analysis: J. Peklar, K. Richardson.
Study supervision: M.C. Henman, M. Kos, R.A. Kenny.
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