Repetitive strain injury

One out of every 10 Canadian adults had a repetitive strain injury (RSI) serious enough to limit their normal activities in 2000/01, according to a new study published today in Health reports, which shows that RSIs are affecting a growing number of adults.

An estimated 2.3 million people aged 20 or older reported having had an RSI at some point in the 12 months prior to their participation in the Canadian Community Health Survey, for which data collection began in September 2000.

This marked an increase in the prevalence of RSIs during the late 1990s. In 1996/97, 8% of adults reported the problem, according to the National Population Health Survey. The proportion hit 10% in 2000/01. Work-related activities were most often the cause.

Repetitive strain injury is an umbrella term for a group of disorders usually caused by repetitive movements that affect the muscles, tendons and nerves. Unlike other injuries, which occur at a single point in time, RSIs develop over an extended period.

In 2000/01, men and women were almost equally likely to report an RSI, although since 1996/97, the percentage of women sustaining such injuries rose faster than the percentage of men. For women, the increase was from 7.9% to 10.3%, compared with an increase from 8.2% to 9.9% for men.

Injury characteristics vary between men and women

Most repetitive strain injuries affected the upper body. About 25% were in the neck or shoulder. Another 23% occurred in the wrist or hand, followed by the back (19%) and then the elbow or lower arm (16%). The remaining 17% involved a lower extremity or unspecified body part.

Men were more likely than women to have hurt their arm, leg or back. In contrast, a higher percentage of women than men reported injuries to their neck, shoulder or hand. These differences are likely attributable to the types of activities each sex undertakes.

Just over half of RSIs sustained by men and women happened while working. For men, sports or physical exercise was the next most frequently cited activity, whereas for women, activities relating to chores, unpaid work or school ranked second.

Certain occupations associated with higher risk

The report found that working did not in itself increase the likelihood of reporting an RSI. However, among those who did work, the type of job mattered.

Least likely to be injured were people in management. Men and women who worked in sales or service; trades, transport or equipment operating; farming, forestry, fishing or mining; and processing, manufacturing or utilities had high odds of reporting an RSI, compared with those in management. This was particularly true for women in traditionally male-dominated occupations.

Stress increases risk

Work stress deriving from a fast work pace, role ambiguity, worry and monotonous tasks has been associated with RSIs in the past. The report supports the association between work stress and RSIs, but also finds that once other contributing factors are taken into consideration, the association differs for men and women.

People who reported at least some work stress were generally more likely to report an RSI in 2000/01 than were those who reported no work stress. This relationship was especially pronounced for women: 18% who indicated that their work was "extremely stressful" reported an RSI, compared with 10% who considered their work "not at all" or "not very" stressful.

Even allowing for other possible explanatory factors, the odds of reporting an RSI were higher among women who found most days at work were "quite" or "extremely" stressful, compared with women who felt lower degrees of work stress. The association between workplace stress and RSI did not hold for men, however, once the same factors were taken into consideration.

There was a significant association for both sexes between day-to-day life stress and reporting an RSI, even after potentially confounding factors were considered. Compared with people who described their lives as "not at all" or "not very" stressful, those experiencing greater degrees of daily stress had higher odds of reporting an RSI.

Chronic pain and distress associated with RSI

In 1998/99, 23% of men and 31% of women with an RSI reported chronic pain or discomfort, compared with 13% of men and 16% of women who did not report an RSI. This association persisted even when factors such as age and arthritis were taken into account. As well, men and women with an RSI reported significantly higher levels of psychological distress than did those without such injuries.

The effects of RSIs can be long-lasting. For women, reporting an RSI in 1998/99 was associated with increased pain and distress by 2000/01, and among men who reported an RSI in 1998/99, the elevated levels of pain and distress had not declined in 2000/01.

Definitions, data sources and methods: survey numbers, including related surveys, 3225 and 3226.

The full article, "Repetitive strain injuries," appears in the August 2003 issue of Health reports, Vol. 14, no. 4 (82-003-XIE, $15/$44; 82-003-XPE, $20/$58), now available. For more information about this article, contact Michael Tjepkema (416-952-4620; michael.tjepkema@statcan.gc.ca), Health Statistics Division.

This issue contains two other articles: "Dependents seniors at home - formal and informal help" and "Impact of chronic conditions."

The article on seniors uses data from the 1996 General Social Survey to estimate the relative number of hours of help that seniors living in private households receive from various sources. It concludes that more than half of this assistance comes from informal sources alone, and that an increase in help from formal sources does not significantly reduce the hours received from informal sources. For more information about this article, contact Sylvie A. Lafrenière (613-951-7197; sylviea.lafreniere@statcan.gc.ca), Health Statistics Division.

The article on chronic conditions uses data from the 1996/97 National Population Health Survey to compare the impact of 21 chronic conditions on health-related quality of life. The effect of these conditions varies substantially by age and by the number of conditions reported. For more information about this article, contact Susan E. Schultz (416-480-6100, ext. 3788; sue.schultz@ices.on.ca), Institute for Clinical and Evaluative Sciences.

For information about Health reports, contact Christine Wright (613-951-1765; christine.wright@statcan.gc.ca), Health Statistics Division.