Shift work and health

Three out of 10 employed Canadians worked some type of shift in 2000/01. Many shift workers reported problems that ranged from sleep disruption to difficulties with relationships. For most of them, working shift was not a choice, but a requirement of employment.

For both sexes, an evening shift in 1994/95 was associated with increases in psychological distress over the following two years, according to a new profile of shift workers published in the latest issue of Health reports.

Men who worked an evening, rotating or irregular shift in 1994/95 had increased odds of having been diagnosed with a chronic condition over a four-year period. For women, a non-standard schedule was not associated with a new diagnosis of chronic conditions during that period.

In 2000/01, 30% of men and 26% of women aged 18 to 54 who were employed throughout the year had non-standard schedules. About one-quarter of shift workers reported evening or night shifts. Rotating and irregular shifts were reported more frequently, each accounting for about 4 in 10 of these workers.

Whether they had an evening, rotating or irregular shift, the majority of shift workers had no choice. However, men were more likely than women to say that it was a requirement of the job: 65% of men and 53% of women working an evening shift reported that they had to. In contrast, 11% of women, but just 3% of men, working an evening shift did so because they were caring for family.

Shift work more common among blue-collar, sales and service workers

Shift work was more common in blue-collar or sales and service occupations than in white-collar or clerical jobs. People working fewer than 30 hours a week were more likely to have non-standard schedules, as were those who worked on weekends.

The likelihood of working shift decreased with advancing age, possibly because older workers with seniority have more choice in their hours than do younger, less experienced workers.

Single or previously married workers were more likely than those who were married to have non-standard schedules.

Male workers living in households with children were less likely than those in childless households to work shifts. There was no difference for female workers, which may be, in part, because of women's greater tendency to cite caring for family as their reason for shift work.

Sleep problems common

Men and women who worked shift were more likely to have trouble falling asleep and staying asleep than regular daytime workers. They were also more likely to report that their sleep was not always refreshing.

Few workers got less than six hours of sleep in a 24-hour period, but this was generally more common among shift than daytime workers.

Evening shift particularly difficult for men

In 1994/95, several types of work stress were relatively common among shift workers: job strain (high psychological demands, but little decision-making authority) for those who worked an evening or rotating shift, and job insecurity for those who worked a rotating or irregular shift. High physical demands were reported by women who did all types of shift work and by men with rotating shifts.

The evening shift seemed to be particularly difficult for men. A high percentage of married men working evenings reported relationship problems with their spouse. For single men, difficulty finding a partner was more common for those working evenings than for those with regular daytime hours.

Men who worked an evening shift were more likely than those with a regular daytime schedule to report a low sense of "mastery," (for example, feeling little control over their life). As well, 45% of men working an evening shift were daily smokers, compared with 27% of daytime workers.

For women, an irregular shift was related to high personal stress (for example, trying to do too many things at once or feeling that others expect too much), and a rotating shift was related to a low sense of mastery.

Shift work may exact a toll on health in long run

The prevalence of chronic conditions among shift workers did not differ significantly from that of daytime workers in 1994/95.

And although disruption of daily living patterns and of sleep might contribute to mental health problems, in 1994/95, distress levels among men and women with non-standard schedules were similar to those of workers with regular daytime schedules.

In the long run, however, shift work may exact a toll on health. Men working an evening, rotating or irregular shift in 1994/95 had higher odds of reporting a diagnosis of a chronic condition in the next four years than did men with regular daytime schedules. For both sexes, working the evening shift in 1994/95 was associated with an increase in psychological distress by 1996/97.

The rigours of working shift may be reflected in the fact that few maintain those hours over several years. Among men and women who worked shift in 1994/95, less than a third continued to do so in both 1996/97 and 1998/99. For the evening shift, the figure was less than one in five. In contrast, three-quarters of workers with regular daytime schedules in 1994/95 still had these hours two and four years later.

The article "Shift work and health" is now available in Health reports, Vol. 13, no 4 (82-003-XIE, $15/$44). A paper version (82-003-XPE, $20/$58) will be available soon. For more information, or to enquire about the concepts, methods or data quality of this release, contact Margot Shields (613-951-4177; margot.shields@statcan.gc.ca), Health Statistics Division.

This issue of Health reports contains two other articles. "Loss and recovery of independence among seniors" examines the characteristics and behaviours that are associated with seniors losing their independence, as well as with dependent seniors regaining their independence. For information on this article, contact Laurent Martel (613-951-2352), Demography Division.

"Disability-free life expectancy by health region" shows substantial differences across health regions in estimates of the years residents can expect to live free of conditions that impede their ability to function in society. For more information on this article, contact Nancy Ross (514-398-4307), Health Analysis and Measurement Group.

For more information about Health reports, contact Marie P. Beaudet (613-951-7025; beaumar@statcan.gc.ca), Health Statistics Division.