Medication use by middle-aged and older participants of an exercise study: results from the Brain in Motion study

BIM is an 18-month quasi-experimental prospective cohort study examining the role of exercise on cognitive function and cerebrovascular physiology [12]. The study consisted of three six-month phases: 1) pre-intervention phase; 2) aerobic exercise intervention phase; and 3) post-intervention phase (Fig. 1) [12]. The Conjoint Health Research Ethics Board at the University of Calgary approved the study, and participants provided written informed consent prior to participating in the study. Medication use was obtained at the time of the baseline assessment (Pre-intervention Phase 1A) (Fig. 1), during which time participants were asked to list the name, formulation, dosages, and frequency of consumption of all medications and supplements that they were currently taking. These agents were then categorized as prescribed (i.e., require a prescription to be obtained from their physician) and non-prescribed, which were further sub-categorized as OTC medications (i.e., available for purchase without a prescription) as natural health products (which included vitamins and minerals, herbal remedies, homeopathic medicines, traditional medicines, or probiotics). We defined drug use intensity as the mean number of medications consumed per person. Years of education were also recorded at baseline, and defined as total years completed in a formal education program starting with primary (elementary) school.

Among the 271 subjects (mean [SD] age 65.9 ± 6.5 years, 54.6% females) enrolled in the Brain In Motion study who completed their baseline assessment (Table 1), most subjects were taking at least one prescription drug (75.3%), natural health product (81.5%), and/or OTC drug (64.2%). The most commonly prescribed medications were cholesterol lowering agents (specifically HMG-CoA reductase inhibitors or statins) and thyroid replacement therapy (Table 2). Vitamin D was the most common natural health product consumed, while non-steroidal anti-inflammatories (NSAIDs) were the most common OTC medication reported (Table 3). The average daily vitamin D intake was 1896 IU per participant with 42% of participants taking more than 2000 IU per day and 10% above 4000 IU (Table 4).

More females than males were taking one or more OTC medications (70% women v 57% men). Natural health products (58% women v 42% men) and prescribed medications (78% women v 72% men) use was similar between the sexes. Older subjects (age > 65 years) were more likely to be taking at least one medication in all three categories and had a higher prescribed drug use intensity (mean number of medications consumed per person) (Table 5). When controlling for age, men and women taking more than two prescribed or OTC medications were less physically fit, as determined by their VO₂max measurements (Table 6).

This study presents data on the pattern of medication use in sedentary but otherwise generally healthy middle-aged and older adults. According to the Chief Public Health Officer’s Report on the State of Public Health in Canada 2010, approximately one-quarter (23%) of Canadian older persons (i.e., 65 or more years of age) suffered from cardiovascular disease and over 4% from stroke. Those with active cardiovascular or debilitating neurological conditions were excluded from entry into our study, which also recruited a number of individuals less than 65 years of age [16]. While 62% of Canadian seniors reported being in very good functional health, nearly one-quarter of them had difficulties with activities such as walking, communicating, seeing, and climbing stairs [16]. BIM participants had to be able to function independently without difficulties. They were able to perform moderate physical activity three times a week, for the 6-month intervention period, and also underwent demanding physiological testing (such as VO₂max tests) a number of times during the 18-month study.

Most subjects (75.3%) were taking at least one prescription drug at baseline (most commonly used were cholesterol lowering agents and L-thyroxine) (Table 2). Canadians in general are heavy users of prescribed medications. A total of $27,734 million (or $795.32 per capita) was spent on prescription drugs nationally in 2012 [6, 17]. In 2012 the most common prescription medication used by older persons in Canada were statins (46.6%), followed by angiotensin-converting-enzyme (ACE) inhibitors (28.4%) and proton pump inhibitors (27%) [18]. While BIM participants commonly were taking statins, their rate of use (19.2%) was less than half of that reported for the general older population (Table 2). Use of ACE inhibitors (8.9%) and proton pump inhibitors (7.4%) was also substantially lower than that reported for the general older Canadian population [9]. This is consistent with our impression that study participants were generally healthier than the older Canadian population. Similar to other studies female sex and older age were associated with a greater intensity of prescribed medication use [6‐9].

A majority of subjects were taking at least one natural health product (81.5%) or OTC medication (64.2%) (Table 1). NSAIDs were the most commonly used OTC medication (30.3%) in our study. One of the commonest reason for supplement use is a desire to improve or maintain overall health [19]. There are limited data to support the health benefits of supplements and natural products in generally healthy individuals, and there is a potential, albeit small, of risk of harm with their use. Adverse drug effects and drug-drug interactions can occur [20‐33]. Supplements can reduce the efficacy of specific medications [10, 22‐25, 28‐37] while the consumption of multiple agents concurrently is associated with a higher risk of non-adherence [35]. Although prescription medications have a higher likelihood of side effects, there is greater regulatory oversight. Since these medications require a prescription, physicians and pharmacists should be informing patients of potential side effects and monitoring for them. With OTC medications the attending physician may be unaware of their use (which is commonly the case) [29] with no monitoring for side effects and assessment for potential interactions. Consumption of these agents tends to increase with age [36]. The use of medications (prescription and OTC) is associated with a decrease in the fitness levels of participants (Table 6). Because of the observational nature of this study no conclusions about a causal relationship can be made. Possibly the presence of various clinical conditions alone or in combination with other ones are associated with both medication use and worse fitness levels.

Nearly three-quarters of our study population were taking vitamin D. The average daily intake was 1896 IU per participant with nearly half consuming more than 2000 IU per day and 10% above 4000 IU (Table 4). Nearly half (47.5%) of the Canadian population is reportedly taking supplemental vitamin D [38] at a median dose of 400 IU/day [39]. Factors reported to be associated with a greater likelihood of use included increasing age, female sex, English language, diagnosis of osteoporosis, perceived lactose intolerance, and university education [38]. In postmenopausal women and men above 50, vitamin D and calcium supplementation might lead to increased bone density and reduce the risk of falls and hip and non-vertebral fractures [40] though these claims are controversial [41, 42]. Adults over 50 years of age are at a moderate risk of vitamin D deficiency. Vitamin dosages as high as 2000 IU/day can safely be given without the need for any monitoring [39, 43]. While some feel doses up to 4000 IU/day are safe [44], others believe that doses above 2000 IU/day should be supervised because of potential risks of hypercalcemia and renal dysfunction [40, 43].

Our study had a number of limitations. We did not know the indications for the medications taken, or whether they were effective for the indication of their use. We were unable to determine whether OTC medications were recommended by a physician or taken without their advice or knowledge. We did not assess adherence. Together, this means that we cannot comment on the appropriateness of the medications being taken. Our emphasis was on describing overall use rather than understanding their indications. Finally, given the strict inclusion criteria for the Brain in Motion study, our findings relating to the medication use in this group, may not be representative of the general population.

This study showed high medication use (prescribed, OTC, and natural health products) in a generally healthy group of middle-aged and older Canadians. Consumption was higher in females, and amongst those older than 65 years. Higher medication usage was associated with a lower fitness level. Rate of medication use was lower than that of the general older Canadian population. The appropriateness of this the high rate of medication use in this generally healthy population deserves further investigation.