Long Working Hours and Health

Abstract

This article examines associations between long working hours, depression and changes in selected health behaviours. Based on an analysis of people followed over a two-year period, the relationship between changes in work hours and changes in health behaviours is explored.
The data are from the household longitudinal component of the 1994/95 and 1996/97 cycles of the National Population Health Survey, conducted by Statistics Canada. Results are based on 3,830 adult workers aged 25 to 54 (2,181 men and 1,649 women) who worked 35 hours or more per week throughout the year before their 1994/95 interview.
Multivariate analyses were used to estimate associations between working hours and depression, and changes in weight, smoking, drinking and exercise, while controlling for potential socioeconomic and work-related confounders such as education, income, occupation, shift work and self-employment.
Women who worked long hours had increased odds of subsequently experiencing depression. Moving from standard to long hours was associated with unhealthy weight gain for men, with an increase in smoking for both men and women, and with an increase in drinking for women. No associations were detected for physical activity.

Full text

Health Reports, Autumn 1999, Vol. 11, No. 2 Statistics Canada, Catalogue 82-003
Long working hours
and health
Margot Shields
33
Abstract
Objectives
This article examines associations between long
working hours, depression and changes in selected
health behaviours. Based on an analysis of people
followed over a two-year period, the relationship
between changes in work hours and changes in health
behaviours is explored.
Data source
The data are from the household longitudinal
component of the 1994/95 and 1996/97 cycles of the
National Population Health Survey, conducted by
Statistics Canada. Results are based on 3,830 adult
workers aged 25 to 54 (2,181 men and 1,649 women)
who worked 35 hours or more per week throughout the
year before their 1994/95 interview.
Analytical techniques
Multivariate analyses were used to estimate
associations between working hours and depression,
and changes in weight, smoking, drinking and exercise,
while controlling for potential socioeconomic and work-
related confounders such as education, income,
occupation, shift work and self-employment.
Main results
Women who worked long hours had increased odds of
subsequently experiencing depression. Moving from
standard to long hours was associated with unhealthy
weight gain for men, with an increase in smoking for
both men and women, and with an increase in drinking
for women. No associations were detected for physical
activity.
Key words
weight gain, smoking, alcohol consumption, exercise,
depression, work schedule tolerance
Author
Margot Shields (613-951-4177; shiemar@statcan.ca) is
with the Health Statistics Division at Statistics Canada,
Ottawa K1A 0T6.
In Canada, a growing share of the workforce is putting
in long hours on the job (see Working hours).1-3
Whether long hours adversely affect health has been
debated for decades. However, policy-makers considering
the regulation of working hours have had difficulty making
decisions based on scientific research.4
In Japan, where long hours are common, a growing
number of workers have been dying from cardiovascular
causes (for instance, stroke, acute cardiac failure, myocardial
infarction and aortic rupture) in their most productive years.
Studies based on workers compensation claims have found
that many of the victims had been putting in long hours
before they died.5,6 The Japanese have named such deaths
Karoshi, meaning death from overwork.
Japanese researchers have proposed a Karoshi model to
examine the relationship between long hours and
cardiovascular disease.5 It is hypothesized that long hours
bring about unhealthy lifestyle changes such as smoking,
alcohol abuse, lack of physical activity, sleeplessness, poor
eating habits, and fewer chances for medical examinations.
Prolonged periods of long hours may also increase anxiety,
strain and irritability. Over time, individuals can become
fatigued and develop a propensity toward obesity. The
cumulative result can be cardiovascular disease.5

Health Reports, Autumn 1999, Vol. 11, No. 2 Statistics Canada, Catalogue 82-003
Long working hours and health34
Methods
Data source
This article is based on data from the National Population Health
Survey (NPHS). The NPHS, which began in 1994/95, collects
information about the health of the Canadian population every two
years. It covers household and institutional residents in all provinces
and territories, except persons living on Indian reserves, on
Canadian Force bases, and in some remote areas. The NPHS has
both a longitudinal and cross-sectional component. Respondents
who are part of the longitudinal component will be followed for up to
20 years.
Individual data are organized into two files: General and Health.
Socio-demographic and some health information is collected for
each member of participating households. These data are found in
the General file. Additional in-depth health information is collected
for one randomly selected household member. This additional
information, as well as the information on the General file pertaining
to that individual, is found in the Health file.
The 1994/95 NPHS provincial, non-institutional sample consisted
of 27, 263 households, of which 88.7% agreed to participate in the
survey. After application of a screening rule (to improve the
representativeness of the sample) 20,725 households remained in
scope. In 18,342 of these households, the randomly selected person
was aged 12 or older. Their response rate to the in-depth health
questions was 96.1% or 17,626 respondents. Of these 17,626
randomly selected respondents, 14,786 were eligible members of
the longitudinal panel. In addition, 468 selected respondents for
whom only general information was collected in 1994/95 and 2,022
randomly selected respondents younger than 12 were also eligible.
Thus, a total of 17,276 longitudinal respondents were eligible for
re-interview in 1996/97. The remaining respondents to the
1994/95 survey were sponsored by provincial governments that
elected to enlarge the sample size in their province for cycle 1 only.
These respondents were not followed up.
A response rate of 93.6% was achieved for the longitudinal panel
in 1996/97. Of these 16,168 respondents, full information was
available for 15,670; that is, general and in-depth health information
for both cycles of the survey.
A more detailed description of the NPHS design, sample and
interview procedures can be found in published reports.7-9
The sample analyzed in this article consists of 3,830 respondents
aged 25 to 54 (2,181 men and 1,649 women) who worked 35 hours
per week or more throughout the entire year before their 1994/95
interview, and from whom information was collected in 1996/97
(Appendix Table A). A small percentage (0.9%) of respondents, for
whom working hours in the year before the 1994/95 survey were
not stated, was excluded. The profile of workers putting in long
hours in 1994/95 is based on the longitudinal file. Estimates based
on the 1994/95 cross-sectional file are very similar (data not shown).
Every effort is made to collect the in-depth health information
directly from the randomly selected individuals. However, in a small
number of cases, proxy responses were accepted in both 1994/95
and 1996/97. Because the primary focus of this analysis is
measurement of the change between the two NPHS cycles, the
records for which a proxy response was accepted for the in-depth
health interview in either cycle (4.4% of respondents) were not
included: 8 respondents for whom only proxy information was
available for both years; 151 with proxy information for 1994/95;
and 18 with proxy information for 1996/97. These respondents were
excluded to reduce potential bias that may have resulted from
response errors due to proxy reporting.
Analytical techniques
All analyses are based on weighted data. The group examined
consists of longitudinal respondents for whom non-proxy information
was available for both 1994/95 and 1996/97. Descriptive statistics
for 25- to 54-year-olds who worked 35 hours per week or more
throughout 1994/95 are presented. Those who worked long hours
(an average of 41 or more hours per week) are compared with those
who worked standard hours (an average of 35 to 40 hours).
Multiple logistic regression was used to model the relationship
between long hours in 1994/95 and a subsequent depressive
episode in 1996/97. Multiple logistic regression was also used to
model the effects of changing or maintaining working hours between
the two surveys (for example, moving from standard to long hours
or working long hours in both survey periods) in relation to changes
in health behaviours; namely, unhealthy weight gain, increased
smoking, increased drinking, and reduced physical activity.
Based on face validity, a review of the literature on occupational
stress,10,11 and availability in the NPHS, selected work-related and
socio-demographic factors were included in the regression models
as control variables. Work-related variables were: occupation, self-
employment, shift work, multiple jobs, high job strain, high job
insecurity, and low supervisor support. Socio-demographic
characteristics included age, marital status, educational attainment,
household income and the presence of children younger than 12 in
the household. Unless otherwise stated, the control variables in
the regression models are based on data collected in the 1994/95
survey.
In all cases, separate regression models were fitted for men and
women. Coefficients of variation and standard errors were estimated
using a weighted bootstrap procedure12,13 that fully accounts for the
design effect of the survey.

Long working hours and health 35
Health Reports, Autumn 1999, Vol. 11, No. 2 Statistics Canada, Catalogue 82-003
Using longitudinal data from the first two cycles
of the National Population Health Survey (1994/95
and 1996/97), this article examines Canadian
workers aged 25 to 54 who worked at least 35 hours
a week in 1994/95). People in this age range are
the most likely to feel stress from the time-crunch,
as they juggle work, family and personal
responsibilities.14
The data are analyzed in the context of the early
phases of the Karoshi model to determine if long
hours (41 or more a week) are associated with
depression and with changes in health behaviours.
Four indicatorsweight, smoking, drinking, and
physical activityare used to investigate if moving
from standard to long hours is related to unhealthy
lifestyle changes (see Methods and Limitations).
Working hours and health
Surprisingly few studies have examined associations
between working hours and health status and
behaviours. Although the effects of shift work have
been studied extensively, it is rare for research to
focus on the quantity of hours.15 Nonetheless, there
is currently sufficient evidence to raise concerns
Working hours
At the turn of the century, a typical worker in Canada put in a 60-
hour week. In the following decades, largely as a result of union
activity, efforts were made to reduce the length of the workweek in
the interests of health and safety. It was widely argued that more
opportunity for rest and time to participate more fully in family life
would have a positive effect on workers physical and mental health.16
As a result, there was a general downturn in working hours, and the
average workweek stabilized in the 35- to 40-hour range in the mid-
1960s.
However, average weekly hours provide an incomplete picture.
Although average hours worked per week have changed very little
since the mid-1960s, a new trend has developed since the economic
downturn of the early 1980s: hours polarization.1-3 The proportions
of male workers putting in both longer (41 or more) and shorter
weekly hours (less than 35) have risen. Among female workers, a
growing percentage work long hours. The proportion of the
population working long hours is highest at ages 25 to 54, and the
shift out of standard to long hours has been the most skewed for
women aged 35 to 54.3
about the health and safety risks of working long
hours.4,15,17
In North America and Europe, research has
focused on the association between high job strain
(high psychological demands coupled with low
decision-making latitude11) and health outcomes
such as depression, anxiety, migraine, high blood
pressure and coronary heart disease,18-28 and health
behaviours such as smoking and excess body
weight.29-31 However, most research based on the
job strain model has not explicitly examined the
impact of the number of working hours.
While researchers in Japan have investigated the
Karoshi phenomenon,5,6 the data are, for the most
part, presented as a series of cases studies; there are
no epidemiologically sound estimates of the
prevalence of Karoshi.6 Other Japanese studies
showing associations between long hours and weight
gain, increased perceived stress, and an unhealthy
lifestyle were based only on men in a small number
of occupational groups.32,33
Among the few studies of the number of hours
worked, a recent report by the Economic and Social
Research Council in Great Britain concluded that
Percentage distribution of usual weekly hours, employees
aged 25 or older, by sex, Canada excluding territories,
selected years 1980 to 1995
Usual
weekly
hours 1980 1985 1989 1995
%
Men 1-34 4.4 5.2 5.2 7.1
35-40 77.5 75.0 73.4 68.6
41+ 18.0 19.7 21.4 24.3
Women 1-34 29.9 30.9 29.3 30.1
35-40 64.5 62.6 63.4 61.3
41+ 5.6 6.5 7.3 8.6
Data source: Reference 3
 Excludes self-employed

Long working hours and health36
Health Reports, Autumn 1999, Vol. 11, No. 2 Statistics Canada, Catalogue 82-003
Limitations
To estimate working hours, respondents were asked about jobs
they had over the previous year. They were asked their usual
weekly working hours and the start and end dates for each job. It
may have been difficult for some respondents to recall this
information. Working hours may be underestimated for those who
had a complex work history over the year, particularly if it involved
multiple jobs.
Professionals and managers often work unpaid overtime to deal
with excessive workloads. These workers may not report those
additional hours, which would result in an underestimate of working
hours for this group.
The calculation to derive average working hours was based on a
maximum of three jobs. Consequently, working hours for individuals
who had more than three jobs during the year would be
underestimated. It is expected that this constraint had only a
minimal impact on the analysis. Using 1994/95 NPHS cross-
sectional data, it is estimated that less than 1% of workers had
more than three jobs over the year. In 1996/97, details were only
asked for a maximum of three jobs. The longitudinal file has details
about a maximum of three jobs for both reference years.
It is not possible to have a complete picture of an individuals
work situation because the NPHS is conducted every two years,
and the questions about work pertain to the year before the date
of the respondents interview. For example, respondents classified
as working standard hours both reference years may not have
done so in the intervening year. This may have had an effect on
the associations of changes observed between reference years.
The calculation of body mass index was based on self-reported
data, and some respondents may have under-reported their weight
and/or over-reported their height.
Respondents were classified as having experienced a new
major depressive episode if they experienced depression in the
year before the 1996/97 survey but not in the year before the
1994/95 survey. It is possible that these respondents may have
had a history of depression; that is, they experienced depression
before the NPHS began, or had an episode in the non-survey year.
The final stage of the Karoshi model
cardiovascular diseasehas not been investigated
extensively. Japanese research, based on case studies
of small samples of male subjects, suggests an
association between long working hours, high blood
pressure and heart disease.35-37 As well, one of these
studies35 detected a U-shaped relationship
between long working hours and the risk of a heart
attack: while men working more than 55 hours per
week had increased odds of experiencing an attack,
so did those working 35 hours per week or less,
long hours have negative health consequences.34
Using data from the British Household Panel Study,
the researchers found that working long hours a
week increased feelings of stress and was associated
with a decline in physical exercise. For women,
several associations were found between long hours
and health, including problems with arms, legs,
hands, and blood pressure.
Measures of socio-
demographic characteristics
All measures of socio-demographic characteristics were derived
using data collected in the 1994/95 survey.
To establish marital status, respondents were asked for their
current marital status. Those who chose the now married,
common-law or living with a partner options were grouped
together as married. Individuals who answered single were
classified as never married, and widowed, separated and
divorced were categorized as previously married.
Respondents were grouped into three education categories
based on the highest level of education attained: high school
graduation or less; some postsecondary; and postsecondary
(college, trade or university) graduation.
Household income was defined based on the number of people
in the household and total household income from all sources in
the 12-month period before the survey.
Household People in Total household
income group household income
Lowest 1 to 4 Less than $10,000
5 or more Less than $15,000
Lower-middle 1 or 2 $10,000 to $14,999
3 or 4 $10,000 to $19,999
5 or more $15,000 to $29,999
Middle 1 or 2 $15,000 to $29,999
3 or 4 $20,000 to $39,999
5 or more $30,000 to $59,999
Upper-middle 1 or 2 $30,000 to $59,999
3 or 4 $40,000 to $79,999
5 or more $60,000 to $79,999
Highest 1 or 2 $60,000 or more
3 or more $80,000 or more

Long working hours and health 37
Health Reports, Autumn 1999, Vol. 11, No. 2 Statistics Canada, Catalogue 82-003
compared with men who worked 40 to 45 hours
per week. It may be that the men working shorter
hours were doing so because of ill health.
Currently, small sample sizes preclude an
examination of the relationship between long
working hours and heart disease based on NPHS
data. In the two years between the first and second
NPHS cycles, for the population under study, the
sample counts for the incidence of heart disease
were 21 men and 13 women; for high blood pressure,
the counts were 57 and 33, respectively.
Workers putting in long hours
In 1994/95, among the population aged 25 to 54
working 35 hours or more per week, a higher
percentage of men than women put in long hours
(Table 1) (see Measures of socio-demographic
characteristics). Half of these men reported 41 or
more hours of work per week, compared with about
one-quarter (28%) of their female counterparts.
Men working long hours averaged 55 per week;
women, 51 (data not shown). Among those working
long hours, 32% of the men and 19% of the women
put in at least 60 hours per week.
For men, long hours were more common at ages
25 to 34 and 35 to 44 than at age 45 or older. By
contrast, for women, working long hours was not
significantly related to age. Marital status was not
associated with long hours for either male or female
workers. However, men in households with young
children were significantly more likely than other
men to work long hours. For women, the
proportion working long hours differed little by the
presence of young children at home.
Postsecondary graduates were significantly more
likely to work long hours, compared with workers
whose formal education had not extended beyond
high school. As well, men and women in high-
income households were more likely than those in
middle-income households to put in long hours. For
men, long hours were also common among those
in households with incomes in the low-to-middle
range.
Table 1
Percentage working long hours among men and women aged
25 to 54 who worked 35 hours or more per week throughout
1994/95, by selected socio-demographic characteristics,
Canada excluding territories
Men Women
Total Long Total Long
number hoursnumber hours
000 % 000 %
Total 4,414 502,789 28
Age
25-34 1,489 52§1,058 26
35-44 1,681 53§1,093 28
45-54 1,244 43 638 30
Marital status
Married 3,477 50 2,016 27
Never married 659 49 410 28
Previously married 278 47 360 32
Missing -- -- -- --
Child(ren) under age 12
in household
Yes 1,841 54 1,043 25
No 2,573 47 1,746 29
Education
Secondary graduation or less 1,439 45 778 23
Some postsecondary 1,086 50 734 26
Postsecondary graduation 1,880 53 1,272 32
Missing -- -- -- --
Household income
Lowest/Lower-middle/Middle 1,143 53§§ 756 25
Upper-middle 1,978 44 1,255 25
Highest 1,064 58§§ 691 35§§
Missing 229 49 87 26
Data source: 1994/95 and 1996/97 National Population Health Survey,
longitudinal sample, Health file
Notes: Based on 2,181 male and 1,649 female longitudinal respondents for
whom non-proxy information was available for 1994/95 and 1996/97. A critical
value of 2.40 instead of 1.96 was used when significance testing involved
comparison of three groups within a variable. Because of rounding, detail
may not add to totals.
 41 or more hours per week
 Significantly higher than women
§ Significantly higher than ages 45-54
 Significantly higher than no children in household
 Significantly higher than secondary graduation or less
§§ Significantly higher than upper-middle income group
 Coefficient of variation between 16.6% and 25.0%
 Coefficient of variation between 25.1% and 33.3%
-- Amount too small to provide reliable estimate

Long working hours and health38
Health Reports, Autumn 1999, Vol. 11, No. 2 Statistics Canada, Catalogue 82-003
Measures of work characteristics
The data in this article dealing with occupation, self-employment,
shift work and multiple job-holding were derived from the first, or
1994/95, cycle of the National Population Health Survey (NPHS).
Occupation was categorized as white-collar (administrative and
professional); clerical, sales or service; and blue-collar, based on
the 1980 Standard Occupational Classification (SOC) system.
Respondents were asked if they worked mainly for others for
wages, salary, or commission, or in their own business, farm or
professional practice. The latter were classified as self-employed.
Unpaid family workers were excluded from the analysis
(5 respondents).
Respondents who reported working anything but a regular
daytime shift were coded as shift workers (including evening shift,
night shift, rotating shift, split shift, irregular/on call schedule or
other).
Some individuals had more than one job at the same time during
the reference year. Those who held two or more jobs concurrently
throughout 1994/95 were classified as multiple job holders.
When a respondent had more than one job during the reference
year, the questions on occupation, self-employment, and shift work
were asked about the job the respondent considered to be his or
her main job.
For each job, respondents were asked how many hours per week
they usually worked at that job. In addition, dates were collected
for each job so that it was possible to calculate the number of
weeks the respondent worked at the job during the year. With this
information, the average number of hours worked per week during
the reference year was calculated across all jobs. This was done
for both reference years on the longitudinal file. Reference year
1994/95 is the year before the interview date of the 1994/95 survey,
and reference year 1996/97 is the year before the interview date
of the 1996/97 survey.
Individuals were classified as working standard hours if, on
average, they worked 35 to 40 hours per week, and as working
long hours if, on average, they worked 41 or more hours. The
analysis in this article is based only on individuals who worked 35
or more hours per week throughout reference year 1994/95.
The pattern of working hours was examined across reference
years by identifying the following categories:
standard-standard: individuals who, on average, worked
standard hours the entire year both reference years
standard-long: individuals who worked the entire year both
reference years, and who, on average, worked standard
hours in reference year 1994/95 and long hours in
reference year 1996/97
standard-reduced: individuals who, on average, worked
standard hours for the entire 1994/95 reference year, and
who reduced their hours to less than 35 per week or did not
work all 52 weeks of reference year 1996/97
long-long: individuals who, on average, worked long hours
the entire year both reference years
long-reduced: individuals who, on average, worked long
hours for the entire 1994/95 reference year, and who
reduced their hours to less than 41 per week or did not
work all 52 weeks of reference year 1996/97
The questions on job strain, job insecurity, and supervisor support
were asked in the 1994/95 survey about the job the respondent had
at the time of the interview. To measure job strain, respondents
were asked to rank their responses to the following seven statements
using a 5-point scale ranging from strongly agree (a score of 1) to
strongly disagree (a score of 5).
1. Your job requires that you learn new things (reverse score).
2. Your job requires a high level of skill (reverse score).
3. Your job allows you freedom to decide how you do your
job (reverse score).
4. Your job requires that you do things over and over.
5. Your job is very hectic (reverse score).
6. You are free from conflicting demands that others make.
7. You have a lot to say about what happens in your job
(reverse score).
Job strain was measured as the ratio of psychological demands
(items 5 and 6) to decision latitude. Items pertaining to decision
latitude include skill discretion (1, 2, and 4) and decision authority (3
and 7). So that the potential contribution of each item to the scores
for decision latitude and psychological demands would be equal,
the summed scores of responses to the items pertaining to each
were divided by 5 and 2, respectively. The ratio for job strain was
then calculated by dividing the new score for psychological demands
by that for decision latitude. For values of the ratio that fell in the
upper quartile of the distribution for the total working population
(scores equal to or greater than 1.18), the respondent was
categorized in a high-strain job. Cronbachs alpha was used to
assess the internal consistency of the job strain scale. The internal
consistency estimate was 0.61 for decision latitude and 0.34 for
psychological demands of work.
Job insecurity was measured by the statement, Your job security
is good. Respondents who replied neither agree nor disagree,
disagree, or strongly disagree were categorized as experiencing
job insecurity.
Supervisor support was measured by the statement, Your
supervisor is helpful in getting the job done. Respondents who
said they disagreed or strongly disagreed were categorized as
receiving low support from their supervisor.

Long working hours and health 39
Health Reports, Autumn 1999, Vol. 11, No. 2 Statistics Canada, Catalogue 82-003
Table 2
Percentage working long hours among men and women aged
25 to 54 who worked 35 hours or more per week throughout
1994/95, by selected employment characteristics, Canada
excluding territories
Men Women
Total Long Total Long
number hoursnumber hours
000 % 000 %
Total 4,414 502,789 28
Occupation
White-collar 1,487 56§1,193 35§
Clerical/Sales/Service 875 46 1,192 22
Blue collar 1,843 45 275 17
Missing 209 59 130 35
Self-employed
Yes 795 80§271 67§
No 3,619 43 2,518 23
Shift worker
Yes 976 57§380 36§
No 3,438 48 2,409 26
Multiple job holder
Yes 247 94§163 82§
No 4,167 47 2,626 24
High job strain
Yes 728 48 816 24
No 3,347 51 1,778 29
Missing 339 42 195 29
High job insecurity
Yes 1,189 49 778 27
No 2,886 51 1,817 28
Missing 339 42 195 29
Low supervisor support
Yes 724 52 444 27
No 3,351 50 2,151 28
Missing 339 42 195 29
Data source: 1994/95 and 1996/97 National Population Health Survey,
longitudinal sample, Health file
Notes: Based on 2,181 male and 1,649 female longitudinal respondents for
whom non-proxy information was available for 1994/95 and 1996/97. A critical
value of 2.40 instead of 1.96 was used when significance testing involved
comparisons of three groups within a variable. Because of rounding, detail
may not add to totals.
 41 or more hours per week
 Significantly higher than women
§ Significantly higher than other item(s) in category
 Coefficient of variation between 16.6% and 25.0%
- - Amount too small to provide reliable estimate
Job characteristics
The propensity to work long hours was associated
with several aspects of employment (see Measures
of work characteristics). Men and women in white-
collar occupations were more likely to report long
hours than were those in clerical, sales and service
occupations or in blue-collar occupations (Table2).
High proportions of shift workers and individuals
who were self-employed worked long hours. And
not surprisingly, long hours were very common
among individuals who worked at more than one
job or business (94% for men and 82% for women).
However, high job strain, high job insecurity and
low supervisor support were not related to working
hours. Among individuals who reported these
situations, there were no significant differences in
the proportions working long versus standard hours.
Changing hours
Most people who worked standard hours in 1994/95
continued to do so throughout 1996/97: 64% of
men and 69% of women (Table3). Men who
worked long hours in 1994/95 were likely to
continue in 1996/97 (66%). However, this was not
the case for women; those who worked long hours
in 1994/95 were about as likely to reduce their hours
as they were to continue with long hours. And the
percentage of men moving from standard to long
hours was close to triple the corresponding
percentage for women (21% versus 8%).
Table 3
Pattern of working hours between 1994/95 and 1996/97 among
men and women aged 25 to 54 who worked 35 hours or more
per week throughout 1994/95, Canada excluding territories
Men Women
%
Standard hours in 1994/95
Continued standard hours in 1996/97 6469
Moved to long hours in 1996/97 21§8
Reduced hours in 1996/97 15 23
Long hours in 1994/95
Continued long hours in 1996/97 6648
Reduced hours in 1996/97 34 52
Data source: 1994/95 and 1996/97 National Population Health Survey,
longitudinal sample, Health file
Notes: Based on 2,164 male and 1,643 female longitudinal respondents for
whom non-proxy information was available for 1994/95 and 1996/97; 17 men
and 6 women were excluded because of missing values for hours of work in
1996/97.
 35 to 40 hours per week
 Significantly higher than other item(s) in category
§ Significantly higher than reduced hours
 Significantly higher than moved to long hours
 41 or more hours per week

Long working hours and health40
Health Reports, Autumn 1999, Vol. 11, No. 2 Statistics Canada, Catalogue 82-003
Depression
Previous studies have shown a number of mental
health problems to be related to the work
environment.18-24 However, most of the emphasis
has been on job strain, with little attention paid to
working hours.
Of the population aged 25 to 54 who worked 35
or more hours per week throughout 1994/95, 5%
of women and 3% of men were classified as having
experienced a new major depressive episode at
Using the methodology of Kessler et al.,38 the National Population
Health Survey defines a major depressive episode (MDE) with a
subset of questions from the Composite International Diagnostic
Interview. These questions cover a cluster of symptoms for
depressive disorder, which are listed in the Diagnostic and
Statistical Manual of Mental Disorders.39 Responses to these
questions were scored and transformed into a probability estimate
of a diagnosis of MDE. If the estimate was 0.9 or more (that is,
90% certainty of a positive diagnosis), then the respondent was
considered to have experienced an MDE in the previous 12 months.
Respondents were classified as having experienced a new MDE if
they experienced an MDE in the year before their 1996/97 interview,
but not in the year before they were interviewed in 1994/95.
The Canadian Guidelines for Healthy Weights use body mass
index (BMI) to determine an acceptable range of healthy weights
and to identify conditions of excess weight and underweight.40 BMI
is calculated by dividing weight in kilograms by height in metres
squared. Four weight categories are identified based on BMI:
Underweight (BMI less than 20)
Acceptable weight (BMI 20 to 24.9)
Some excess weight (BMI 25 to 27)
Overweight (BMI greater than 27).
These guidelines are recommended for everyone aged 20 to 64,
excluding pregnant women. In accordance with these guidelines,
for this analysis, individuals whose BMI was 25 or higher in 1994/95
were classified as having excess body weight.
The BMI scale is intended to be used as a continuum where
the risk of developing health problems increases with shifts away
from the generally acceptable range. Rapid changes within and
between BMI categories should be considered as important
indicators of potential problems.40 To classify individuals as having
an unhealthy weight gain, the average percentage gain was
calculated separately for men and women between the two
reference years for individuals whose BMI was 20 or more in 1994/95.
For men, the average gain was 0.7%, with a standard deviation of
5.7%. For women, the average gain was 1.2%, with a standard
deviation of 7.6%. Individuals were then classified as having an
unhealthy weight gain if their percentage weight gain between
reference years was more than one standard deviation above the
mean: more than 6.4% for men and more than 8.8% for women.
People who were underweight in 1994/95 were not classified as
having an unhealthy weight gain, regardless of how many pounds
they had gained by 1996/97.
To classify smokers, the NPHS asked respondents if they currently
smoked cigarettes daily, occasionally or not at all. Daily smokers
were asked how many cigarettes they smoked each day.
Respondents were identified as having increased daily smoking if
they had been occasional or non-smokers in 1994/95 and had
become daily smokers by 1996/97, or if they were daily smokers in
both surveys and the number of cigarettes smoked per day increased
by three or more (a pack a week) between the two surveys.
To measure alcohol consumption, respondents were asked the
number of drinks they had on each day in the week before the survey.
A drink was defined as one bottle of beer or a glass of draft, one
glass of wine or a wine cooler, or one drink or cocktail with one and
a half ounces of liquor. Respondents were classified as having
increased their alcohol consumption if the number of drinks
consumed in the week before the 1996/97 interview exceeded the
number consumed before the 1994/95 interview.
The frequency of physical activity was based on the number of
times in the previous three months that respondents had participated
in a leisure-time physical activity that lasted more than 15 minutes.
Monthly frequency was derived as the number of times in the past
three months divided by 3. Respondents were considered to have
decreased their physical activity if they reported fewer periods of
exercise in 1996/97 than they had in 1994/95.
Measures of health
some time in the 12 months before their 1996/97
interview (Table4) (see Measures of health). Women
who worked long hours in 1994/95 had 2.2 times
the odds of reporting having experienced a major
depressive episode, compared with those who
worked standard hours (Appendix Table B). For
men, no relationship was found between depression
and long working hours. However, consistent with
numerous other studies, high job strain was related
to depression for both sexes.18-24

Long working hours and health 41
Health Reports, Autumn 1999, Vol. 11, No. 2 Statistics Canada, Catalogue 82-003
Weight
Body mass index (BMI) is a measure of weight in
relation to height. A BMI greater than 27 is
associated with increased occurrence of
hypertension, coronary heart disease and
diabetes.40-42 The 25-to-27 range is suggested as a
caution zone that may lead to health problems in
some people.
Among the group of workers examined in this
analysis, a much higher proportion of men than
women were overweight in 1994/95 (BMI greater
than 27): 36% versus 23% (Table4). Similarly, the
proportion of men having some excess weight (BMI
25 to 27) was close to double that for women: 25%
compared with 13%. The men with excess weight
(BMI 25 or higher) weighed, on average, 196 pounds
(89 kilograms); the women averaged 168 pounds (76
kilograms).
When factors such as age, education, smoking
status, occupation, shift work and work stress were
taken into account, men who worked long hours in
1994/95 had increased odds (1.4) of having excess
body weight (data not shown). Among women, this
association was not found.
Between 1994/95 and 1996/97, the average
weight gain for the group of workers analyzed in
this article was minimal: about 1 pound (0.45
kilograms) for men and 2 pounds (0.91 kilograms)
for women. Nevertheless, approximately 10% of
both men and women had an unhealthy weight gain.
The men gained an average of 19 pounds (8.6
kilograms); the women, 21 pounds (9.7 kilograms).
For men, moving from standard to long hours
was associated with unhealthy weight gain (Chart1).
Table 4
Selected health indicators, men and women aged 25 to 54
who worked 35 or more hours per week throughout 1994/95,
Canada excluding territories
Men Women
New major depressive episode, 1996/97 (%) 35
Body mass index, 1994/95
Some excess weight (BMI 25 to 27) (%) 25§13
Overweight (BMI greater than 27) (%) 36§23
Average weight in pounds/kilograms
1994/95 180.7/82.0§141.7/64.3
Average weight in pounds/kilograms
1994/95 for individuals with excess
weight (BMI 25 or higher) 195.7/88.8§167.6/76.0
Weight gain, 1994/95 to 1996/97
Average % weight gain 0.9 1.6
Average gain in pounds/kilograms 1.2/0.5 2.0/0.9
Unhealthy weight gain
% with unhealthy weight gain 10 10
Average gain in pounds/kilograms 19.1/8.6 21.4/9.7
Daily smoker, 1994/95 (%) 28 25
Increase in daily smoking,
1994/95 to 1996/97 (%) 9 7
Average increase (cigarettes per day) 10 8
Increase in weekly alcohol consumption,
1994/95 to 1996/97 (%) 34 §25
Average increase (drinks per week) 6 3
Decrease in periods of leisure-time
physical activity, 1994/95 to 1996/97 (%) 43 41
Average decrease (periods per month) 16§14
Data source: 1994/95 and 1996/97 National Population Health Survey,
longitudinal sample, Health file
Note: Based on male and female longitudinal respondents for whom non-
proxy information was available for 1994/95 and 1996/97. Excludes
missing.
 Significantly higher than men (p = 0.05)
 Coefficient of variation between 16.6% and 25.0%
§ Significantly higher than women (p = 0.05)
 Coefficient of variation between 25.1% and 33.3%
Chart 1
Percentage of men and women aged 25 to 54 who worked 35
or more hours per week throughout 1994/95 and had unhealthy
weight gain, by pattern of working hours between 1994/95 and
1996/97, Canada excluding territories
Data source: 1994/95 and 1996/97 National Population Health Survey,
longitudinal sample, Health file
Notes: For both men and women, a one-tailed test was carried out to
determine if the outcome measure was higher for individuals who were
standard - long, compared with those who were standard - standard.
Significance testing was not done for other patterns of working hours.
 Coefficient of variation between 16.6% and 25.0%
 Coefficient of variation between 25.1% and 33.3%
* Significantly higher than standard - standard; one-tailed test, p = 0.05
Men
Women
0 4 8 12 16
Working hours
(1994/95 - 1996/97)
% with unhealthy weight gain (1994/95 - 1996/97)
†
†
‡
‡
‡
‡
†*
Standard - Long
Standard - Reduced
Long - Long
Long - Reduced
Standard - Standard
Standard - Standard
Standard - Long
Long - Long
Standard - Reduced
Long - Reduced

Long working hours and health42
Health Reports, Autumn 1999, Vol. 11, No. 2 Statistics Canada, Catalogue 82-003
Men
Women
0 4 8 12 16
Working hours
(1994/95 - 1996/97)
% with increase in daily smoking (1994/95 - 1996/97)
†
†
‡
‡
‡
‡*
†
†*
Standard - Long
Standard - Reduced
Long - Reduced
Standard - Standard
Long - Long
Standard - Long
Long - Reduced
Standard - Reduced
Standard - Standard
Long - Long
And even when factors such as age, education,
smoking status, occupation, shift work and work
stress were taken into account, men whose hours
changed from standard to long had more than twice
the odds (2.2) of experiencing an unhealthy weight
gain, compared with men who continued to work
standard hours (Appendix TableC). Among
women, no significant associations were found
between unhealthy weight gain and changes in
working hours, although there was a significant
relationship with job strain. Women classified as
having high job strain in 1994/95 had increased odds
(1.8) of experiencing an unhealthy weight gain by
1996/97.
Smoking
In 1994/95, 28% of the male and 25% of the female
workers in this analysis were daily smokers (Table4).
There was, however, no relationship between
working hours and the propensity to be a daily
smoker in 1994/95 (data not shown). As well, unlike
other studies that have found an association between
job strain and smoking,29,30 this analysis found no
significant relationship for either sex.
Between 1994/95 and 1996/97, 9% of the male
and 7% of the female workers increased their daily
smoking; that is, they either became daily smokers
(after being non-smokers or occasional smokers) or
increased the number of cigarettes they smoked per
day by at least three (Table 4). Men who increased
their smoking, smoked, on average, an additional
10 cigarettes per day; for women, the average daily
increase was 8.
For both sexes, changing from standard to long
hours was associated with increased smoking
(Chart2). But as is true for weight gain, factors
such as age and education can affect smoking
behaviour. Therefore, to understand the relationship
between smoking and a change in working hours,
this analysis takes these factors into consideration,
along with other employment characteristics such
as occupation, shift work and work stress. Men who
changed from standard to long hours had more than
twice the odds of an increase in daily smoking,
compared with men who continued to work standard
hours; the corresponding odds for women were
more than four times higher (Appendix Table D).
Alcohol consumption
Between 1994/95 and 1996/97, 34% of the male
workers and 25% of the female workers in this
analysis increased their weekly alcohol consumption
(Table4). Men who increased their consumption
had, on average, an additional six drinks per week,
while women had, on average, three more drinks.
Among women, higher alcohol consumption was
associated with changes in working hours (Chart 3).
Those who moved from standard to long hours had
higher odds of increased consumption, compared
with those who continued to work standard hours
(Appendix Table E). Women who had worked long
hours in 1994/95 and subsequently reduced their
hours also had high odds of increased drinking.
For men, an increase in weekly hours was not
associated with consuming more alcohol. However,
those who had worked standard hours in 1994/95
and reduced their hours by 1996/97 had significantly
lower odds of increasing their alcohol consumption.
Chart 2
Percentage of men and women aged 25 to 54 who worked 35
or more hours per week throughout 1994/95 and had increase
in daily smoking, by pattern of working hours between 1994/95
and 1996/97, Canada excluding territories
Data source: 1994/95 and 1996/97 National Population Health Survey,
longitudinal sample, Health file
Notes: For both men and women, a one-tailed test was carried out to
determine if the outcome measure was higher for individuals who were
standard - long, compared with those who were standard - standard.
Significance testing was not done for other patterns of working hours.
 Coefficient of variation between 16.6% and 25.0%
 Coefficient of variation between 25.1% and 33.3%
* Significantly higher than standard - standard; one-tailed test, p = 0.05

Long working hours and health 43
Health Reports, Autumn 1999, Vol. 11, No. 2 Statistics Canada, Catalogue 82-003
Men
Women
0 1020304050
Working hours
(1994/95 - 1996/97)
% with decrease in periods of leisure-time physical activity
(1994/95 - 1996/97)
Standard - Reduced
Long - Long
Standard - Long
Standard - Standard
Long - Reduced
Standard - Long
Long - Long
Standard - Standard
Long - Reduced
Standard - Reduced
This might reflect health problems that could have
prompted the reduction in hours of work. Male
shift workers, too, had significantly low odds of
reporting increased drinking.
Physical activity
In 1994/95, the male workers included in this
analysis exercised, on average, 19 times per month,
while the female workers exercised 17 times per
month. For both sexes, there were no significant
differences in the average number of times
exercising between those who worked standard and
those who worked long hours (data not shown).
Between 1994/95 and 1996/97, 43% of men and
41% of women reduced the number of times they
exercised. However, those who decreased their
exercise tended to have had significantly higher levels
to begin with: the men had exercised an average of
29 times per month in 1994/95, and the women, 27
times (data not shown). By 1996/97, these men
and women had reduced their exercise level to an
average of 13 times per month.
However, changes in working hours were not
related to a decrease in physical activity (Chart 4).
The odds that workers who moved from standard
to long hours would report fewer periods of exercise
were not significantly different from the odds for
workers who continued with standard hours
(Appendix Table F). Thus, among the four lifestyle
consequences of long hours that are hypothesized
by the Karoshi model and that are examined in this
analysis, a reduction in physical activity is the only
one not supported by NPHS data.
These findings are somewhat unexpected, as an
increase in time on the job is likely to reduce the
time available for exercise. As well, the lack of an
association between hours of work and physical
activity in the NPHS runs counter to the previously
mentioned British study.34 However, those
researchers used a more detailed breakdown of
hours of work, and detected an association between
excessively long hours (60 or more a week) and
lower levels of physical activity. Moreover, the
British study did not report the relationship between
changes in working hours and time devoted to
physical activity.
Chart 4
Percentage of men and women aged 25 to 54 who worked 35
or more hours per week throughout 1994/95 and experienced
decrease in periods of leisure-time physical activity, by pattern
of working hours between 1994/95 and 1996/97, Canada
excluding territories
Chart 3
Percentage of men and women aged 25 to 54 who worked 35
or more hours per week throughout 1994/95 and had increase
in weekly alcohol consumption, by pattern of working hours
between 1994/95 and 1996/97, Canada excluding territories
Data source: 1994/95 and 1996/97 National Population Health Survey,
longitudinal sample, Health file
Notes: For both men and women, a one-tailed test was carried out to
determine if the outcome measure was higher for individuals who were
standard - long, compared with those who were standard - standard.
Significance testing was not done for other patterns of working hours.
 Coefficient of variation between 16.6% and 25.0%
* Significantly higher than standard - standard; one-tailed test, p = 0.05
Men
Women
0 10203040
Working hours
(1994/95 - 1996/97)
% with increase in weekly alcohol consumption
(1994/95 - 1996/97)
†
*
Data source: 1994/95 and 1996/97 National Population Health Survey,
longitudinal sample, Health file
Notes: For both men and women, a one-tailed test was carried out to
determine if the outcome measure was higher for individuals who were
standard - long, compared with those who were standard - standard.
Significance testing was not done for other patterns of working hours.

Long working hours and health44
Health Reports, Autumn 1999, Vol. 11, No. 2 Statistics Canada, Catalogue 82-003
To further investigate the issue, a finer breakdown
of working hours in the NPHS data was considered:
standard (35 to 40 hours per week), somewhat long
(41 to 59 hours), and excessively long (60 or more
hours). Modest decreases in exercise levels were
observed among women who moved from standard
to somewhat long hours and among men who
moved from somewhat long to excessively long
hours. In all other cases, there were modest increases
in exercise levels (data not shown). When the
analysis was repeated eliminating those who did not
exercise at all in 1994/95, the patterns were similar.
The inability to detect a significant association
between an increase in working hours and a decrease
in exercise levels may indicate that some respondents
use exercise to cope with potential stressors
associated with long working hours. However, a
possible confounding factor may be seasonality. The
time devoted to exercise varies throughout the year
and tends to peak in the summer. NPHS
respondents activity levels were measured only once
in each survey cycle, and individuals who increased
their working hours from standard to long or
somewhat long to 60 or more hours per week were
more likely to have been interviewed in the summer.
Concluding remarks
From the turn of the century to the 1960s, Canada
experienced a decline in working hours, which led
some economists to predict a 32-hour workweek.43
This has not happened. In fact, the proportions of
men and women putting in long hours have been
rising since the early 1980s.3
In 1994/95, half of male and over a quarter of
female full-time year-round workers spent at least
41 hours a week on the job. For both sexes, long
hours were associated with high educational
attainment, white-collar occupations, and
predictably, self-employment, shift work, and
multiple job holding. For men, long hours were also
associated with being aged 25 to 44, having young
children at home.
Relatively little research has been devoted to the
health implications of working long hours. It is not
yet known whether the Japanese Karoshi model can
be applied to Canada. However, data from the
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Long working hours and health46
Health Reports, Autumn 1999, Vol. 11, No. 2 Statistics Canada, Catalogue 82-003
Table A
Longitudinal sample aged 25 to 54 working 35 or more hours
per week throughout 1994/95, by sex, Canada excluding
territories
Men Women
Total 2,181 1,649
Occupation
White-collar 728 723
Clerical/Sales/Service 412 714
Blue collar 954 133
Missing 87 79
Self-employed
Yes 392 147
No 1,789 1,502
Shift worker
Yes 508 248
No 1,673 1,401
Multiple job holder
Yes 139 98
No 2,042 1,551
High job strain
Yes 365 485
No 1,696 1,070
Missing 120 94
High job insecurity
Yes 594 466
No 1,467 1,089
Missing 120 94
Low supervisor support
Yes 357 258
No 1,704 1,297
Missing 120 94
Age
25-34 754 622
35-44 799 619
45-54 628 408
Education
Secondary graduation or less 735 426
Some postsecondary 521 446
Postsecondary graduation 921 775
Missing 4 2
Marital status
Married 1,574 1,056
Never married 391 302
Previously married 216 290
Missing -- 1
Child(ren) under age 12 in household
Yes 775 557
No 1,406 1,092
Household income
Lowest/Lower-middle/Middle 590 487
Upper-middle 1,039 794
Highest 458 324
Missing 94 44
Data source: 1994/95 and 1996/97 National Population Health Survey,
longitudinal sample, Health file
Note: Includes only longitudinal respondents for whom non-proxy 1994/95
and 1996/97 information was available.
-- Nil
Appendix
Table B
Adjusted odds ratios relating selected characteristics to
probability of major depressive episode in 1996/97 among men
and women aged 25 to 54 who worked 35 or more hours per
week throughout 1994/95, Canada excluding territories
Men Women
95% 95%
Odds confidence Odds confidence
ratio interval ratio interval
Long working hours0.6 0.3, 1.3 2.2* 1.1, 4.4
White-collar0.5 0.2, 1.4 1.6 0.8, 3.1
Self-employed- - ... 0.2 0.0, 3.2
Shift worker0.7 0.3, 1.6 2.3 0.9, 6.0
Multiple job holder- - ... - - ...
Work stress
High job strain3.3* 1.3, 8.5 2.1* 1.1, 4.0
High job insecurity1.6 0.7, 4.1 1.0 0.5, 1.9
Low supervisor support0.6 0.0, 26.5 1.4 0.7, 2.9
Age
25-341.0 ... 1.0 ...
35-44 1.0 0.3, 2.7 0.8 0.4, 1.6
45-54 0.9 0.2, 3.1 0.9 0.3, 2.5
Married0.8 0.2, 2.6 0.9 0.4, 2.1
Child(ren) under age 12
in household2.6 0.8, 8.0 1.4 0.6, 3.3
Education
Secondary graduation or less1.0 ... 1.0 ...
Some postsecondary 0.5 0.1, 1.7 0.3* 0.1, 0.8
Postsecondary graduation 0.5 0.2, 1.2 0.5 0.3, 1.0
Household income
Lowest/Lower-middle/Middle 0.2* 0.0, 0.7 1.8 0.6, 5.3
Upper-middle 0.3* 0.1, 0.9 1.7 0.7, 4.3
Highest1.0 ... 1.0 ...
Data source: 1994/95 and 1996/97 National Population Health Survey,
longitudinal sample, Health file
Notes: Based on 2,151 male and 1,632 female longitudinal respondents for
whom non-proxy information was available for 1994/95 and 1996/97; 46 men
and 75 women were categorized as having a major depressive episode in
reference year 1996/97. Missing categories for occupation, income and work
stress variables were included in the model to maximize sample size; however,
their respective odds ratios are not shown. Unless otherwise noted, all
characteristics refer to 1994/95.
 Reference category is absence of characteristic; for example, the reference
category for long working hours is standard working hours.
 Reference category for which odds ratio is always 1.0
- - Sample counts were very low for the number of individuals experiencing a
major depressive episode for certain variables in the models; namely self-
employed men (4), men with multiple jobs (4) and women with multiple jobs
(5). This resulted in instability in the regression models and, therefore, these
variables were removed from the models. The conclusions based on the
analysis were similar regardless of whether these variables were included.
* p
≤
0.05
... Not appropriate

Long working hours and health 47
Health Reports, Autumn 1999, Vol. 11, No. 2 Statistics Canada, Catalogue 82-003
Table C
Adjusted odds ratios relating selected characteristics to
unhealthy weight gain between 1994/95 and 1996/97 among
men and women aged 25 to 54 who worked 35 or more hours
per week throughout 1994/95, Canada excluding territories
Men Women
95% 95%
Odds confidence Odds confidence
ratio interval ratio interval
Working hours
(1994/95 - 1996/97)
Standard - standard1.0 ... 1.0 ...
Standard - long 2.2* 1.2, 4.0 0.8 0.3, 2.2
Standard - reduced 1.5 0.7, 3.4 0.6 0.2, 1.3
Long - long 1.3 0.8, 2.1 0.9 0.4, 1.9
Long - reduced 1.2 0.6, 2.1 0.5 0.2, 1.1
Occupation
White-collar0.7 0.4, 1.0 0.7 0.4, 1.2
Self-employed1.0 0.6, 1.7 0.8 0.3, 2.1
Shift worker1.3 0.8, 1.9 1.6 0.9, 3.1
Multiple job holder1.0 0.5, 1.9 1.7 0.6, 4.7
Work stress
High job strain1.0 0.6, 1.7 1.8* 1.0, 3.2
High job insecurity1.3 0.8, 1.9 0.9 0.5, 1.5
Low supervisor support0.9 0.6, 1.5 1.1 0.6, 2.3
Age
25-341.0 ... 1.0 ...
35-44 1.1 0.8, 1.7 0.9 0.5, 1.6
45-54 0.8 0.5, 1.2 0.6 0.3, 1.3
Married0.6 0.4, 1.0 0.9 0.5, 1.5
Child(ren) under age 12
in household0.8 0.5, 1.2 0.9 0.5, 1.7
Education
Secondary graduation
or less1.0 ... 1.0 ...
Some postsecondary 0.8 0.5, 1.3 0.7 0.3, 1.3
Postsecondary graduation 1.0 0.6, 1.5 0.9 0.4, 1.8
Household income
Lowest/Lower-middle/
Middle 0.8 0.4, 1.5 2.0 0.8, 4.6
Upper-middle 1.0 0.6, 1.6 1.2 0.6, 2.6
Highest1.0 ... 1.0 ...
Daily smoker (1996/97)0.7 0.4, 1.1 0.6 0.3, 1.2
Data source: 1994/95 and 1996/97 National Population Health Survey,
longitudinal sample, Health file
Notes: Based on 2,134 male and 1,512 female longitudinal respondents for
whom non-proxy information was available for 1994/95 and 1996/97; 228 men
and 144 women were categorized as having an unhealthy weight gain between
reference years. Missing categories for occupation, income and work stress
were included in the model to maximize sample size; however, their respective
odds ratios are not shown. Because of rounding, some confidence intervals
with 1.0 as the lower limit were significant. Unless otherwise noted, all
characteristics refer to 1994/95.
 Reference category, for which odds ratio is always 1.0
 Reference category is absence of characteristic; for example, the reference
category for self-employed is paid worker.
* p
≤
0.05
... Not appropriate
Table D
Adjusted odds ratios relating selected characteristics to
increased daily smoking between 1994/95 and 1996/97 among
men and women aged 25 to 54 who worked 35 more hours
per week throughout 1994/95, Canada excluding territories
Men Women
95% 95%
Odds confidence Odds confidence
ratio interval ratio interval
Working hours
(1994/95 - 1996/97)
Long - long 1.1 0.6, 2.0 1.0 0.3, 2.9
Standard - long 2.2* 1.1, 4.5 4.1* 1.4, 11.6
Long - reduced 1.2 0.6, 2.3 1.7 0.8, 4.0
Standard - reduced 1.7 0.7, 4.2 1.3 0.6, 2.8
Standard - standard1.0 ... 1.0 ...
Occupation
White-collar0.6 0.3, 1.0 0.4* 0.2, 0.8
Self-employed0.5* 0.3, 0.9 0.9 0.3, 2.4
Shift worker1.0 0.6, 1.9 1.3 0.5, 3.1
Multiple job holder1.5 0.6, 3.9 1.2 0.4, 3.8
Work stress
High job strain1.0 0.6, 1.7 0.9 0.5, 1.6
High job insecurity0.7 0.4, 1.1 1.4 0.8, 2.3
Low supervisor support0.9 0.5, 1.6 1.3 0.7, 2.7
Age
25-341.0 ... 1.0 ...
35-44 0.7 0.4, 1.2 0.9 0.5, 1.8
45-54 0.6 0.3, 1.1 0.9 0.4, 2.1
Married0.9 0.5, 1.6 0.5* 0.3, 0.9
Child(ren) under age 12
in household1.0 0.6, 1.7 1.2 0.6, 2.3
Education
Secondary graduation
or less1.0 ... 1.0 ...
Some postsecondary 1.0 0.6, 1.7 0.5 0.3, 1.1
Postsecondary graduation 0.5* 0.3, 0.9 0.4* 0.2, 0.7
Household income
Lowest/Lower-middle/
Middle 0.9 0.5, 1.7 0.6 0.2, 1.4
Upper-middle 0.9 0.5, 1.6 0.7 0.3, 1.6
Highest1.0 ... 1.0 ...
Data source: 1994/95 and 1996/97 National Population Health Survey,
longitudinal sample, Health file
Notes: Based on 2,156 male and 1,637 female longitudinal respondents for
whom non-proxy information was available for 1994/95 and 1996/97; 189 men
and 118 women had increased their smoking between reference years.
Missing categories for occupation, income and work stress variables were
included in the model to maximize sample size; however, their respective
odds ratios are not shown. Unless otherwise noted, all characteristics refer to
1994/95.
 Reference category for which odds ratio is always 1.0
 Reference category is the absence of characteristic; for example, the
reference category for self-employed is paid worker.
* p
≤
0.05
... Not appropriate

Long working hours and health48
Health Reports, Autumn 1999, Vol. 11, No. 2 Statistics Canada, Catalogue 82-003
Table E
Adjusted odds ratios relating selected characteristics to
increased weekly alcohol consumption between 1994/95 and
1996/97 among men and women aged 25 to 54 who worked 35
or more hours per week throughout 1994/95, Canada excluding
territories
Men Women
95% 95%
Odds confidence Odds confidence
ratio interval ratio interval
Working hours
(1994/95 - 1996/97)
Long - long 0.9 0.6, 1.3 1.5 0.9, 2.5
Standard - long 1.1 0.7, 1.7 2.0* 1.1, 3.4
Long - reduced 0.8 0.6, 1.3 1.6* 1.0, 2.6
Standard - reduced 0.5* 0.3, 0.9 1.0 0.6, 1.5
Standard - standard1.0 ... 1.0 ...
Occupation
White-collar0.9 0.7, 1.2 1.0 0.7, 1.4
Self-employed1.1 0.8, 1.5 0.9 0.5, 1.7
Shift worker0.7* 0.5, 1.0 0.9 0.6, 1.5
Multiple job holder1.0 0.6, 1.9 0.6 0.3, 1.3
Work stress
High job strain1.1 0.8, 1.6 1.0 0.7, 1.4
High job insecurity0.9 0.7, 1.2 1.1 0.7, 1.5
Low supervisor support1.1 0.8, 1.6 1.1 0.7, 1.7
Age
25-341.0 ... 1.0 ...
35-44 1.0 0.7, 1.3 0.7 0.5, 1.0
45-54 0.7 0.5, 1.0 0.9 0.6, 1.4
Married0.9 0.7, 1.3 1.1 0.8, 1.5
Child(ren) under age 12
in household1.1 0.8, 1.5 0.8 0.5, 1.1
Education
Secondary graduation
or less1.0 ... 1.0 ...
Some postsecondary 0.8 0.6, 1.1 1.0 0.7, 1.6
Postsecondary graduation 0.8 0.6, 1.0 1.2 0.7, 1.9
Household income
Lowest/Lower-middle/
Middle 0.8 0.5, 1.2 1.2 0.7, 2.1
Upper-middle 0.9 0.7, 1.3 1.2 0.8, 1.9
Highest1.0 ... 1.0 ...
Data source: 1994/95 and 1996/97 National Population Health Survey,
longitudinal sample, Health file
Notes: Based on 2,120 male and 1,626 female longitudinal respondents for
whom non-proxy information was available for 1994/95 and 1996/97; 696
men and 408 women increased their weekly alcohol consumption between
reference years. Missing categories for occupation, income and work stress
variables were included in the model to maximize sample size; however, their
respective odds ratios are not shown. Because of rounding, some confidence
intervals with 1.0 as the lower/upper limit were significant. Unless otherwise
noted, all characteristics refer to 1994/95.
 Reference category for which odds ratio is always 1.0
 Reference category is the absence of characteristic; for example, the
reference category for self-employed is paid worker.
* p
≤
0.05
... Not appropriate
Table F
Adjusted odds ratios relating selected characteristics to
decreased physical activity between 1994/95 and 1996/97
among men and women aged 25 to 54 who worked 35 or more
hours per week throughout 1994/95, Canada excluding
territories
Men Women
95% 95%
Odds confidence Odds confidence
ratio interval ratio interval
Working hours
(1994/95 - 1996/97)
Long - long 1.1 0.8, 1.4 1.1 0.7, 1.7
Standard - long 1.0 0.7, 1.6 1.4 0.8, 2.3
Long - reduced 0.9 0.7, 1.3 0.9 0.6, 1.4
Standard - reduced 1.2 0.7, 1.9 1.0 0.6, 1.5
Standard - standard1.0 ... 1.0 ...
Occupation
White-collar0.9 0.7, 1.2 1.0 0.7, 1.4
Self-employed1.1 0.8, 1.5 1.1 0.7, 1.9
Shift worker1.0 0.7, 1.2 0.9 0.6, 1.4
Multiple job holder0.9 0.6, 1.5 1.0 0.5, 1.8
Work stress
High job strain1.0 0.7, 1.4 0.8 0.6, 1.2
High job insecurity1.1 0.8, 1.4 0.9 0.7, 1.2
Low supervisor support0.9 0.7, 1.3 1.0 0.7, 1.5
Age
25-341.0 ... 1.0 ...
35-44 0.9 0.7, 1.2 0.9 0.7, 1.3
45-54 1.1 0.8, 1.4 0.8 0.6, 1.2
Married1.0 0.7, 1.3 0.9 0.6, 1.2
Child(ren) under age 12
in household1.1 0.8, 1.4 1.0 0.7, 1.3
Education
Secondary graduation
or less1.0 ... 1.0 ...
Some postsecondary 1.0 0.7, 1.3 1.1 0.8, 1.7
Postsecondary graduation 1.0 0.8, 1.4 1.1 0.8, 1.6
Household income
Lowest/Lower-middle/
Middle 0.8 0.6, 1.2 1.0 0.6, 1.5
Upper-middle 1.2 0.9, 1.6 0.7 0.5, 1.0
Highest1.0 ... 1.0 ...
Data source: 1994/95 and 1996/97 National Population Health Survey,
longitudinal sample, Health file
Notes: Based on 2,153 male and 1,635 female longitudinal respondents for
whom non-proxy information was available for 1994/95 and 1996/97; 952 men
and 655 women decreased their physical activity between reference years.
Missing categories for occupation, income and work stress variables were
included in the model to maximize sample size; however, their respective
odds ratios are not shown. Unless otherwise noted, all characteristics refer to
1994/95.
 Reference category for which odds ratio is always 1.0
 Reference category is the absence of characteristic; for example, the
reference category for self-employed is paid worker.
... Not appropriate