Health Reports
Prescription medication use among Canadian children and youth, 2012 to 2017

by Jennifer Servais, Pamela L. Ramage-Morin, Julia Gal and Craig M. Hales

Release date: March 17, 2021

DOI: https://www.doi.org/10.25318/82-003-x202100300001-eng

In 2002, the Commission on the Future of Health Care in Canada reported on the growing importance and costs of drugs in the Canadian health care system.Note 1 At that time, prescribed drug expenditures totalled $14.8 billion and represented 12.8% of total health spending.Note 2 By 2019, prescribed drug expenditures were projected to be more than double ($34.3 billion), accounting for 13.0% of health care spending in Canada and surpassed only by those associated with hospitals (26.6%) and physicians (15.1%).Note 2 Prescribed drugs were projected to make up 85.1% of all drug expenditures, with non-prescribed drugs comprising the remaining 14.9%.Note 3 An international comparison revealed that Canada’s per capita drug expenses were high among Organisation for Economic Co-operation and Development countries. For example, in 2016, drug expenses averaged $1,043 per person in Canada, placing it in third place behind the United States ($1,470) and Switzerland ($1,353).Note 4

Prescription medications are used throughout the life course, including among children and youth. Data from the Canadian Health Measures Survey (CHMS) from 2007 to 2011 revealed that 12% of those aged 6 to 14 years had used a prescription medication in the previous two days, with boys more likely than girls to have used medications—14% and 9%, respectively.Note 5 Prescription medication use rose to 26% among those aged 15 to 24 years, at which time medication use was lower among males (13%) than females (40%), with contraceptives contributing to this significant difference. In a U.S. study based on National Health and Nutrition Examination Survey (NHANES) data from 2011 to 2014, Hales et al.Note 6 reported that 22% of children and adolescents (aged 0 to 19 years) had used at least one prescription medication in the prior 30 days and 9% had used two or more over the same period. Their study showed that the use of prescription medications increased with age, from 17% among infants (birth to 23 months) to 26% among adolescents aged 12 to 19 years.Note 6 Prescription medications commonly used by children and adolescents included asthma medications (6%), antibiotics (5%), attention deficit hyperactivity disorder (ADHD) medications (4%) and topical agents (4%).

Prescribing practices may be influenced by emerging medical conditions, the availability of new medications, changing clinical practices, and evolving knowledge of the safety and effectiveness of medications.Note 7 The CHMS provides national-level information on the use of prescribed medications by Canadians in the past month. The objective of this study was to describe past-month prescription medication use among children and youth aged 3 to 19 years, as well as determine the percentage of youth aged 14 years or older who reported ever having misused prescription medication. Combined data from three CHMS cycles spanning 2012 to 2017 will provide a benchmark for comparisons over time and across jurisdictions.

Methods

Data source

The CHMS is an ongoing cross-sectional survey that samples households from five regions across Canada (Atlantic provinces, Quebec, Ontario, the Prairies and British Columbia). Participants provide demographic, socioeconomic, health and lifestyle information through an in-person, computer-assisted household interview, followed by direct physical measurements collected at a mobile examination centre (MEC). The CHMS excludes full-time members of the Canadian Armed Forces, residents of the three territories, people living on First Nations reserves and other Indigenous settlements in the provinces, residents of institutions such as nursing homes, and residents of certain remote regions. Altogether, these exclusions represent approximately 4% of the target population. Parents or guardians answered questions about their children aged 3 to 11 years; and proxy interviews were accepted for those aged 12 years or older in cases of physical or intellectual impairment.

Data from cycles 3 (2012 to 2013), 4 (2014 to 2015) and 5 (2016 to 2017) were combined for this analysis. At each cycle, data were collected from January (year 1) through December (year 2) at 16 randomly selected sites and two MECs distributed across the five regions. The combined response rates for the household and MEC components were 51.7%, 53.7% and 48.5% for cycles 3, 4 and 5 respectively. The surveys were weighted to account for the sample design and non-response. The weights were divided by three so that the estimates were representative of the Canadian population from 2012 to 2017. Details on the sampling design, data collection and calculation of response rates are available in the CHMS Data User Guides and the Instructions for Combining Multiple Cycles of the CHMS Data.Note 8

Study sample

This study sample was composed of 7,892 children and youth (3,950 males and 3,942 females) aged 3 to 19 years from cycles 3 (n=2,601), 4 (n=2,621) and 5 (n=2,670) of the CHMS. Data for all variables were not collected at every cycle or for every age group. Therefore, some analyses were based on subsamples. Information on these limitations are included in the Definitions section and in the table notes.

Definitions

In the Medication use module of the CHMS questionnaire, information on up to 45 medications that were prescribed or administered by a health professional and used in the past month was recorded from the bottles or containers that respondents brought to their interviews. Over-the-counter medications that were prescribed were included as prescription medications. Information was not collected on medications that were prescribed but not used, such as an epinephrine auto-injector. Prescription medications were classified according to Health Canada’s Anatomical Therapeutic Chemical (ATC) classification code, a system developed by the World Health Organization that classifies products according to the organ or system on which they act and their chemical, pharmacological and therapeutic properties (Appendix Table A). Medications taken in the month prior to the MEC visit were verified and included in the study. The current study presents estimates for any medication use (i.e., the use of one or more different medications in the past month) and the use of two or more different medications over the same period. Prevalence estimates of medication use were stratified by sex to establish whether sex-related differences existed and were then presented by age group, household income and household education.

Age group was based on age at the time of the MEC visit. Estimates of medication use were presented for children and youth aged 3 to 5, 6 to 11 and 12 to 19 years to facilitate comparisons with recent U.S. results.Note 6

For CHMS cycles 3 (2012 to 2013) and 4 (2014 to 2015), household income was reported for the previous year in response to the question, “What is your best estimate of your total household income received by all household members, from all sources, before taxes and deductions, during the year ending December 31?” The income questions were not asked in Cycle 5 (2016 to 2017). Instead, respondents were asked for permission to link to tax data for all household members. Total household income was imputed when it was not reported during the interview (cycles 3 and 4) or when the respondent refused permission to link to tax data or a link could not be established. Personal income was imputed as the median revenue of the respondent’s imputation class based on their age, sex and collection site.Note 9 Overall, household income was imputed for 25% of the study sample. The median household income ($88,000) of the study population was used to classify respondents as below the median versus at or above the median.

Household education indicates the highest level of education acquired by any member of the household and was classified as less than postsecondary or a higher level of educational attainment.

Self-reported general health was based on the question, “In general, would you say your health is: (excellent, very good, good, fair, or poor)?” Respondents were classified into three groups: excellent or very good, good, or fair or poor. The self-reported mental health question was limited to those aged 12 years or older with non-proxy interviews. The question and response categories were in the same format and classified for general health.

Body mass index (BMI) was calculated as measured weight in kilograms divided by measured height in meters squared (kg/m2) and rounded to two decimal places. BMI among children and youth aged 3 to 17 years was classified as underweight, normal range, overweight or obesity based on age- and sex-specific percentiles from BMI growth charts developed by the Centers for Disease Control and Prevention in the United States (Table 1).Note 10 The BMI values of respondents aged 18 or 19 were categorized according to Health Canada’s Canadian Guidelines for Body Weight Classification in Adults.Note 11

Respondents reported (yes/no) whether they had a regular medical doctor.

Chronic conditions were described as long-term conditions, which are expected to last or have already lasted six months or more and that have been diagnosed by a health professional. From the range of chronic conditions collected in the CHMS, four were selected for the analysis that a) had sufficient sample sizes and could yield reliable estimates (see Quality of estimates) and b) were relevant for children and youth: asthma, mood disorder (e.g., depression, bipolar disorder, mania or dysthymia), learning disability and attention deficit disorder (ADD). CHMS content is revised periodically and—therefore—the latter two conditions were included only in cycles 3 (2012 to 2013) and 4 (2014 to 2015). It is important to note that the CHMS survey question refers to ADD, while Health Canada’s ATC classification code refers to “agents used for attention deficit hyperactivity disorder,” i.e., ADHD.

The CHMS includes an illicit drug use module administered to non-proxy participants aged 14 years or older. It includes one question about the misuse of prescription medications: “Have you ever used or tried prescription drugs for non-medicinal purposes, for the experience, for the feeling they cause or to get high?” Response categories were either yes or no. Information on specific medications that had been misused was not collected. Responses were examined by sex and household income. The sample size was insufficient for analyzing by level of household education.

Analytical techniques

All estimates were weighted at the person level to represent the population after taking into account the sample design as well as non-response at the household interview and MEC.Note 8 Descriptive statistics were used to estimate the number and percentage of prescription medication users by sociodemographic and health-related characteristics. Except where specified in the Definitions section, estimates were based on pooled data from three CHMS cycles, representing the population from 2012 to 2017. Detailed medication use to the second and third levels of the ATC classification code was presented by age group. Sample sizes and the quality of estimates guided decisions on the number of medication classes presented for each age group (see Quality of estimates). The percentage of youth aged 14 years or older who reported misusing prescription medications was presented by sex. Sample numbers—total and by sex and cycle—are provided (see Study sample). Otherwise, only weighted numbers are presented. The CHMS assumes a Student’s t-distribution with the following denominator degrees of freedom: 33 for cycles 3, 4 and 5; 22 for cycles 3 and 4. To account for survey design effects, 95% confidence intervals and significance testing were estimated with the bootstrap technique (500 iterations). Comparisons were done using t-tests, and the significance level alpha was set at 0.05. The data were analyzed using SAS 9.3 (SAS Institute, Cary, North Carolina) and SUDAAN 11.0 (RTI International, North Carolina).

Quality of estimates

Estimates with high sampling variability (16.6 < coefficient of variation [CV] ⋜33.3%) indicating marginal quality are designated with a superscript E and should be used with caution. Estimates with a CV greater than 33.3% are unacceptable for publication. A minimum sample of 10 respondents in the numerator is required for publication.

Results

The weighted CHMS sample (n=7,892) represented 6.5 million children and youth aged 3 to 19 years during 2012 to 2017. Table 2 presents selected demographic and health-related characteristics of the study population.

Prescription medication use

An estimated 23% of Canadian children and youth (1.5 million) had used at least one prescription medication in the past month according to results from the 2012 to 2017 CHMS (Tables 3-1 and 3-2). Individuals aged 12 to 19 years were significantly more likely than those in the younger age groups to have taken medication. Overall, females were more likely than males to have used prescription medication—26% versus 20% respectively. However, when examined by age group, the difference was evident only among those aged 12 to 19 years, where 39% of females had used a prescription medication in the past month compared with 25% of males. Contraceptive use by 18% of females aged 12 to 19 years accounts in large part for this difference (Table 4).

There was no difference in past-month prescription medication use by household income (Tables 3-1 and 3-2). Prescription medication use did not differ by education for males, but females from households with lower educational attainment were significantly more likely to have used prescription medication than those from higher education households—33% versus 24% respectively. At least some of this difference can be accounted for by the higher use of psychoanaleptics among females from lower education households (9%; 95% CI: 5.5 to 15.1) than among higher education households (4%; 95% CI: 2.6 to 5.0, data not shown). Psychoanaleptics include antidepressants and agents used for ADHD (Appendix Table A).

Two or more medications

From 2012 to 2017, 9% of individuals aged 3 to 19 years had used two or more prescription medications in the past month (Tables 3-1 and 3-2). Youth aged 12 to 19 years were twice as likely as those aged 3 to 11 years to have used more than one prescription medication—13% versus 6%. There were no significant differences in the use of two or more prescription medications in the past month by level of household education or income when both sexes of all ages were considered together.

A comparison of males and females in their use of two or more medications revealed no significant difference among 3- to 5-year-olds. Males in the 6 to 11 year age group were more likely than females to have used at least two medications in the past month (7% versus 4%), but the opposite was true for the older age group (12 to 19 years, 9% versus 17%). Females from lower income households were more likely than their male counterparts to have used two or more prescription medications in the past month—11% versus 7%. The differences observed between males and females in the higher household income and household education groups were not significantly different.

Prescription medication and health

There was a gradient of increasing prescription medication use with lower levels of self-perceived general and mental health (Table 5). For example, among children and youth who rated their general health as very good or excellent, 19% had used at least one prescription medication in the past month, increasing to 32% for those whose health was reported as good and to 49% for people with fair or poor self-reported health. There was no difference in prescription medication use by BMI classification. Most children and youth (89%) had a regular medical doctor (Table 2). This was associated with a higher likelihood of prescription medication use for females but not males (Table 5).

Use of prescription medication was at least twice as common for children and youth with the selected chronic conditions. For example, among those with asthma, more than half (51%) reported past-month prescription medication use, compared with 19% of those without asthma (Table 5). The percentages using prescription medication in the past month were significantly higher for children and youth with a mood disorder (71%), ADD (60%) or a learning disability (43%) than for those without each of these conditions. A commonly used class of medications was psychoanaleptics (Figure 1, Appendix Table A). For example, among those with a mood disorder, 50% had used a psychoanaleptic-class medication in the past month, compared with 4% of children and youth who did not have a mood disorder.

Types of medication (Anatomical Therapeutic Chemical code) by age group

Ages 3 to 5 years

Medications from three classes that were used by 1% or more of young children in the past month were for the respiratory system (R), anti-infectives for systemic use (J) and dermatologicals (D) (Table 4, Appendix Table A). For the respiratory system, an estimated 4% of children (46,000) aged 3 to 5 used drugs for obstructive airway diseases (R03), including asthma. While this class includes inhalants and systemic drugs, only inhalants were commonly reported (R03A and R03B). Approximately 3% had reported systemic use of antibacterials (J01), most of which were penicillin beta-lactam antibacterials (J01C). A third class of prescription medication was corticosteroids, dermatological preparations (D07), most or all of which were corticosteroids, plain (D07A), which were used by just over 1% of children. Less than 1% of individuals aged 3 to 5 years had used drugs for constipation (A06A) in the past month.

Ages 6 to 11 years

Nervous system (N) medications were prescribed and used by children aged 6 to 11 years (Table 4, Appendix Table A). More than 84,000 (4%) were prescribed psychostimulants, agents used for ADHD and nootropics (N06B). Psycholeptics (N05), which include antipsychotics, hypnotics and sedatives, were used by less than 1% of this age group. Drugs for obstructive airway diseases (R03), including asthma, were used by an estimated 4% of those aged 6 to 11 years and, as with the youngest age group, only inhalants were commonly reported (R03A and R03B). Another commonly reported drug used for the respiratory system was nasal preparations (R01), primarily decongestants and other nasal preparations for topical use (R01A), with a past-month use of just over 1%. An estimated 2% of this age group used antibacterials (J01), most of which were penicillin beta-lactam antibacterials (J01C).

Ages 12 to 19 years

The most commonly used prescription medication among this age group was hormonal contraceptives for systemic use, which was reported by approximately 269,000 females (18%) (Table 4, Appendix Table A). A more detailed breakdown shows that 3% (95% CI: 1.5 to 4.9) of females aged 12 to 14 years used hormonal contraceptives for systemic use, compared with 26% (95% CI: 21.9 – 31.5) of those aged 15 to 19 years (data not shown). Nervous system (N) medications that were prescribed and used included antidepressants (N06A) (5%), as well as psychostimulants, agents used for ADHD and nootropics (N06B) (5%). Psycholeptics (N05) were used by approximately 2% of those aged 12 to 19. Past-month use of analgesics (N02), which are also for the nervous system, was reported by an estimated 48,000 youth (2%). As with the younger age groups, youth aged 12 to 19 years used prescription medications for obstructive airway diseases (R03), including asthma (4%), and antibacterials for systemic use (J01) (3%). Prescription dermatologicals (D) used by youth included anti-acne preparations (D10) and corticosteroids (D07).

Misuse of prescription medications

Respondents aged 14 years or older were asked whether they had ever used or tried prescription drugs for non-medicinal purposes, for the experience, for the feeling they cause or to get high. Among youth aged 14 to 19 years, an estimated 97,000 youth (4%; 95% CI: 2.9 to 5.7) stated that they had done so. Although females were more likely than males to have used prescription medications (Tables 3-1 and 3-2), there was no difference by sex in the percentages of those who had ever misused them (data not shown). Prescription medication misuse did not differ significantly by household income (data not shown), and the sample size was insufficient for estimating misuse by level of household education.

Discussion

This study provides details about prescription medication use among children and youth aged 3 to 19 years in Canada’s 10 provinces from 2012 to 2017. An estimated 23% of this young population reported recent (i.e., in the past month) prescription medication use, which is comparable with the United States, where—from 2011 to 2014—22% of people aged 19 years or younger reported past-month prescription medication use.Note 6 Among adolescents in Canada and the United States, females were more likely than males to use prescription medication. In Canada, this can be attributed—at least in part—to the use of contraceptives among adolescent girls. In the United States, the use of antidepressants, antibiotics and analgesics was higher among adolescent females than adolescent males.Note 12

According to the CHMS, the percentage of Canadian children and youth who had used two or more medications in the past month was 9%—the same as has been reported for the United States using data from the NHANES for 2011 to 2014.Note 6 The use of two or more medications differed by age group in Canada and the United States according to the current study and the NHANES by Hales et al.,Note 6 respectively. The CHMS revealed that, among children aged 6 to 11 years, past-month use of two or more medications was more common among boys than girls. The same was reported in the United States by Qato et al.Note 12 using NHANES data for 2003 to 2014. Unlike in the United States,Note 12 Canadian girls aged 12 to 19 were more likely than boys in the same age group to have used two or more medications in the past month. Note that Qato et al.Note 12 reported on the concurrent use of two or more medications in the past month, whereas results from the CHMS may reflect concurrent or consecutive use. Qato et al.Note 12 reported that 1 in 12 children and adolescents who were concurrent prescription medication users were at risk of serious drug interactions, which can result in injury or death.

There was no difference in prescription medication use by household income, which is consistent with other studies.Note 5Note 6 This is counterintuitive, as having a lower income is generally associated with poorer healthNote 13 and—therefore—higher prescription medication use among members of lower income households might be expected. However, lack of affordability may be a barrier to meeting medication needs.Note 14Note 15 Lower income households are less likely to have private drug coverage and an estimated three million Canadians have reported that they could not afford to purchase at least some of their prescribed medications.Note 16 On the other hand, there are over 100 federal, provincial and territorial drug plans in Canada, as well as catastrophic coverage designed to help ensure that people receive the medications they require.Note 16 The lack of association between income and prescription medication use may indicate that public drug plans are compensating for lower incomes, at least for the medication needs of children and youth.

Hales et al.Note 6 reported that medication use did not differ by household level of education, whereas the current study found that lower household educational attainment was associated with prescription medication use, albeit for females only. The more common use of antidepressants and psychostimulants among females from lower education households accounts for at least part of this difference. Mental health conditions, such as depressed mood and anxiety, commonly emerge in adolescence and early adulthood and have been associated with risk factors including lower socioeconomic status.Note 17Note 18 Mood and anxiety disorders tend to be more prevalent among girls, while behavioural disorders such as ADHD are more common among boys.Note 18 Gender differences in the prevalence of these conditions may reflect real differences, as well as differential diagnoses.Note 19 Future studies could help establish whether higher medication use among females from lower education households reflects differences in morbidity, diagnoses, help-seeking behaviours, prescribing practices or other factors. Differences in patterns of prescription medication use in Canada and the United States by education and income may reflect differences in the health care systems related to these characteristics, such as public and private health insurance coverage and access to health care.

Poor health was associated with prescription medication use among young Canadians. Some medications are commonly used throughout childhood and adolescence, such as those for obstructive airway diseases, including asthma. Exposure to air pollution and second-hand smoke have been associated with respiratory conditions in children and youth,Note 20Note 21 likely contributing to the use of medications starting at an early age. However, the need for respiratory system medications may decline with reductions in antibiotic prescribing. A recent study found lower rates of asthma among children with fewer antibiotic prescriptions in their first year of life.Note 22 Other medications, such as those for treating acne and depression, were only evident among adolescents. A number of the therapeutic classes of medications prescribed to children and youth in Canada were similar to those prescribed in the United States and elsewhere.Note 6Note 23Note 24 Among the 10 most commonly used medications in the Netherlands, United Kingdom and ItalyNote 23 were those that were also common in Canada, including, antibacterials for systemic use (J01); drugs for obstructive airway diseases (R03); corticosteroids, dermatological preparations (D07); analgesics (N02); anti-acne preparations (D10); and sex hormones and modulators of the genital system (G03). However, psychoanaleptics (N06) used to treat depression and ADHD were not among the top 10 in the 3 European countries, but were common in Canada for those aged 6 to 19 years. A population-based study on individuals aged 17 years or younger from British Columbia found that they were two to five times more likely than those in Europe to have used psychoanaleptics.Note 25 Hales et al.Note 6 reported that, in the United States, 6.2% of children aged 6 to 11 years and 3.8% of youth aged 12 to 19 years used medications to treat ADHD from 2011 to 2014. In 2016, an estimated 5.5% of those aged 2 to 17 years in the United States were reported to have used medications for ADHD.Note 26 Estimates for Canada for 2012 to 2017 did not differ substantially. The use of ADHD medications has increased in the United States since the 1999 to 2002 period.Note 6 Further investigation could establish whether the same trend exists in Canada.

Data from the CHMS indicate that 4% of youth aged 14 years or older have used or tried prescription drugs for non-medicinal purposes, for the experience, for the feeling they cause or to get high. Survey respondents were not asked about the specific medications they had misused. One example of prescription medication misuse in Canada is the misuse of fentanyl patches and other opioids.Note 27Note 28 The misuse of opioids is of particular concern, as they are highly addictive. There is evidence that younger people and more recent cohorts of youth in particular are at greater risk of developing problems with opioid misuse.Note 29 In Ontario, 114 youth aged 15 to 24 died from an opioid overdose over an 18-month period ending in June 2018; most were unintentional deaths rather than suicides or undetermined deaths.Note 30 The 2019 Ontario Agency for Health Protection and Promotion surveillance reportNote 30 indicated that individuals may misuse their own prescription medications or those that have been prescribed to others.

Strengths and limitations

This large, population-based study was representative of prescription medication use among children and youth in Canada’s provinces from 2012 to 2017. Detailed information was collected directly from medication containers, eliminating the need for individuals to recall this information accurately. Product information numbers were recorded and, if they were not available, interviewers searched the MedSearch database using the product name, manufacturer, active ingredients, route of administration, form and/or product strength. ATC classification codes were assigned and the information was presented at three- and four-digit levels from the main anatomical or pharmacological groups to the pharmacological or therapeutic subgroups.

There are a number of limitations. It was not established whether the use of more than one medication in the past month signified concurrent or consecutive use, which has implications for drug–drug interactions. The chronic conditions—asthma, learning disability, mood disorder and ADD—were self-reported and not verified by another source. The relatively small CHMS sample size limited the number of reportable estimates for medication classes, especially among children aged 3 to 5 years. Many estimates of medication use by class were of marginal quality because of high sampling variability and need to be viewed with caution, as noted in the tables. The analysis is limited to one period in time, and there is no indication of whether the estimates have been stable over time. Information on the use of over-the-counter medications and other health products, including natural health remedies, was collected in the CHMS but not included in this study unless the product was prescribed.

Conclusion

Medications are an important component of Canada’s health care system. Nearly one-quarter of children and youth use prescription medications, particularly those indicated for diseases of the respiratory and nervous systems, such as asthma and ADHD. Prescribing practices may be influenced by the development of new medications, evidence of drug safety and effectiveness, and the emergence and diagnosis of conditions. This study contributes benchmarks of prescription medication use among Canadians aged 3 to 19 years, including an estimate of misuse among those aged 14 to 19 years.

Appendix

References
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