Evaluation of health-related quality of life using EQ-5D in Takamatsu, Japan
Environ Health Prev Med
Evaluation of health-related quality of life using EQ-5D in Takamatsu, Japan
Ai Fujikawa 0 1 2
Takeshi Suzue 0 1 2
Fumihiko Jitsunari 0 1 2
Tomohiro Hirao 0 1 2
0 F. Jitsunari Sanyo Gakuen University and College , Okayama , Japan
1 A. Fujikawa T. Suzue T. Hirao Department of Public Health and Social Medicine, Faculty of Medicine, Kagawa University , Takamatsu, Kagawa , Japan
2 A. Fujikawa (&) Takamatsu City Public Health Center , 10-27 Sakura-machi 1-chome, Takamatsu, Kagawa 761-0074 , Japan
Objectives Healthy Japan 21 (Japanese National Health Promotion in the 21st Century) was started in 2000 to promote extension of healthy life expectancy and improve health-related quality of life (HRQOL). The present study aims to describe HRQOL of Japanese subjects using the EuroQol questionnaire (EQ-5D) and investigate the influence of social background, health-related behaviors, and chronic conditions on HRQOL using representatives in Takamatsu, Japan. Methods Data were obtained from a 2005 Takamatsu City health survey mailed to 2,500 randomly selected Japanese individuals in Takamatsu, a medium-sized city. We examined data from 915 Japanese adults. The questionnaire addressed social background, health-related behaviors, chronic conditions, EQ-5D items, and self-rated health. The impact of social background, health-related behaviors, and chronic conditions on Japanese HRQOL was examined through multivariate regression, adjusting for age and sex. Results EQ-5D scores decreased with age, particularly for respondents who were unemployed or retired. Adjusting for sex and age, the results showed that age, unemployment/ retirement, feeling severe stress, and musculoskeletal and gastrointestinal diseases were significantly associated with decreased HRQOL. Conversely, sufficient sleep (7-8 h/day) and having a hobby were significantly associated with increased HRQOL. Conclusions Information is lacking regarding HRQOL in Japanese populations. This study furthers our understanding of some important determinants influencing Japanese HRQOL, using the EQ-5D in Takamatsu, Japan. Our results also resembled some findings from similar studies in other countries. We hope to use the EQ-5D with other health survey questionnaires to gather more data about HRQOL of Japanese people.
HRQOL; Healthy Japan 21; EQ-5D; Health-related behaviors; Chronic conditions
In recent years, health-related quality of life (HRQOL) has
received much worldwide attention, and several
multiattribute health status classifications have increasingly been
used to describe and evaluate HRQOL in Japan. Healthy
Japan 21 (Japanese National Health Promotion in the 21st
Century), a Japanese health policy introduced in 2000 [
aims to promote extension of life expectancy and improve
HRQOL in all Japanese people.
Internationally, studies using the EuroQol (EQ-5D)
survey have demonstrated lower scores in older individuals
compared with younger individuals [
], lower scores in
women than in men [
], lower scores in individuals of
lower socioeconomic status compared with individuals of
higher socioeconomic status [
2, 3, 6, 8
], and lower scores
in individuals with lower educational attainment than in
those with higher educational attainment [
2, 4, 6, 7
] has been translated into Japanese, and
the official Japanese version was developed in May 1998
]. In a past study in a Japanese population,
moderate problems in at least one dimension were reported
by a quarter of 621 interview respondents, while only
2.1% of respondents reported extreme problems .
Respondents who were elderly, had experiences of
serious illness, had lower educational background, were
retired or were engaged in housewife were more likely to
report problems [
]. However, few studies have
evaluated the relationships between EQ-5D index and social
background, health-related behaviors, and chronic
conditions in the Japanese general population. According to
common health surveys in Japan (e.g., the
Comprehensive Survey of Living Conditions of the People by the
Ministry of Health, Labor, and Welfare), self-rated health
(SRH) has mainly been used to investigate subjective
HRQOL in the general Japanese population [
1, 23, 24,
]. However, it is difficult to describe Japanese
HRQOL as a multidimensional concept using only a
SRH questionnaire. The present study aims to describe
HRQOL of Japanese people using EQ-5D and
investigate the influence of social background, health-related
behaviors, and chronic conditions on HRQOL. We
investigated responses from 915 Japanese individuals in Takamatsu
Data in this study were obtained from a 2005 Takamatsu
City health survey. Takamatsu is a medium-sized city
located in Kagawa Prefecture in western Japan [
Takamatsu City covers an area of 375.09 km2, with a
population of 418,125 people. The residential density is
1,795 people/km2 (2008). The aim of this survey is to
investigate the health state of Japanese general people in
Takamatsu City; 2,500 surveys were mailed to randomly
selected residents in October 2005. A statement about
informed consent was included with the questionnaire, and
returning the questionnaire was considered to constitute
provision of informed consent. Of these 2,500 surveys,
1,196 were returned by respondents. Of these, 281 were
deemed unusable due to missing data. This left 915
surveys, for a usable response rate of 36.6%.
The survey addressed social background,
health-related behaviors, 11 chronic conditions, EQ-5D items, and
Regarding social background, we surveyed age, sex,
family, living status, marital status, and employment
status. Respondents were classified by age as 18–29, 30–39,
40–49, 50–59, 60–69, 70–79, and C80 years. From
selfreported height and weight, we calculated body mass index
(BMI) and created the following three categories:
underweight (\18.5 kg/m2), normal weight (18.5–24.9 kg/m2),
and obese (C25 kg/m2). Contents of health-related
behaviors were: (1) current smoking, (2) excessive alcohol
intake (C44 g/day), (3) regular exercise (moderate or
vigorous exercise for [30 min, C3 times/week), (4)
sufficient sleep (7–8 h/day), (5) having a hobby, and (6)
feeling severe stress. We also surveyed family, living
status, and other health-related behaviors (e.g., eating
breakfast every day, eating lots of vegetables, going out
well, and joining social activity); however, these data did
not correlate significantly with HRQOL data, therefore
corresponding results are not reported herein. Regarding
severe stress, participants were asked if they had felt
severe stress over the past month. Chronic conditions
covered 11 major medical chronic conditions:
hyperlipidemia, hypertension, heart disease (including coronary
heart disease and any other heart condition), stroke, liver
disease, diabetes mellitus, respiratory disease, renal
disease, musculoskeletal disease, gastrointestinal (GI)
disease, and dental caries or other dental diseases.
Respondents answered ‘‘yes’’ if they had each chronic
condition and were taking pharmacotherapy prescribed by
or were currently under the treatment of a doctor. All
respondents were asked both EQ-5D items and to provide
a 5-point self-rating of health (very good, good, neither
good nor bad, poor, or very poor).
All information on the characteristics of the sample was
based on questions from this Takamatsu City health survey.
Data were based on unidentified information from
individuals who agreed to participate, and data collection was
performed within the scope of city council activity.
We obtained permission to publish this study from the
Medical Ethics Committee of Kagawa University on 28
April 2010 (permission no. 22-8).
EQ-5D is a brief, self-completed instrument for describing
and valuing quality of health states defined by the EQ-5D
index. This descriptive system classifies respondents into
one of 243 distinct health states. The descriptive system
consists of five dimensions: (1) mobility, (2) self-care,
(3) usual activities, (4) pain/discomfort, and (5) anxiety/
depression. Each dimension has three levels, allowing for
35 (i.e., 243) possible health combinations. In addition, for
completeness, the states ‘‘dead’’ and ‘‘unconscious’’ were
also incorporated in the framework [
]. The unique
EQ5D health state is defined by combining one level from
each of the five dimensions and producing a set of utility
values for 245 health states (EuroQol Group, http://www.
euroqol.org). We used the Japanese EQ-5D instrument to
assess the QOL of participants .
Because we supposed that age, health-related behaviors,
and chronic conditions were likely to exert some influence
on Japanese HRQOL, we analyzed these relationships.
Bivariate analyses, such as two-way analysis of frequency
with the v2 test and nonparametric statistics (Mann–
Whitney U test or Kruskal–Wallis test), were used to
examine relationships between EQ-5D indicators and other
data from respondents (statistical tests were performed
using a 5% significance level). Using multiple linear
regression analyses, HRQOL scores were modeled using
social background, health-related behaviors, and chronic
conditions as independent variables. Impact on HRQOL
scores, adjusted by other covariates, was evaluated using
values of the regression coefficient. Calculations of the
percentage of respondents reporting problems in different
EQ-5D dimensions, mean EQ-5D index values, standard
error of the mean (SEM), calculation of p values, and
multiple regression analyses were performed using SPSS
version 14.0 software (SPSS Japan Inc., Tokyo, Japan) for
The distribution of respondents according to age and sex,
and that of 2005 Takamatsu City population, is shown
in Table 1. The ratio of respondents aged 40–69 years
was slightly higher than that in the general population of
The demographic details of respondents are presented
in Table 2. Mean age was 51.4 years [standard deviation
(SD) 16.8 years; range 18–95 years]. Mean EQ-5D index
was 0.877 (SD 0.157) and declined with age.
Respondents were predominantly female and married, with 36.4%
employed full time, 21.5% engaged in housewife, and
16.9% unemployed or retired. Mean BMI was 22.4 kg/m2,
with 18.8% of respondents having BMI C25 kg/m2.
Regular exercise ([30 min, C3 times/week) was performed
by about a quarter of respondents (24%), and 72.3% did
not get 7–8 h/day of sleep. Almost a quarter of respondents
were smokers (23.8%), and 5.0% reported excessive
alcohol intake (C44 g/day). Over four-fifths (82.8%)
reported having a hobby. Feelings of severe stress in the
past month were reported by about a quarter of
respondents (27.2%), and almost half (47.7%) had at least one
chronic condition. Percentages of respondents reporting
problems on each EQ-5D dimensions were higher in older
The age gradient was significant across all dimensions
except for anxiety/depression. Employment status and
reporting a problem on the EQ-5D were also significantly
related, with respondents who were unemployed or retired
being more likely to report some problem on all
dimensions. According to health-related behaviors, respondents
without a hobby and those who had experienced severe
stress within the past month were more likely to report
some problem across all dimensions except for self-care.
As shown in Tables 2 and 3, almost half of respondents
reported at least one chronic condition, with hypertension
in 15.8%, heart disease in 3.9%, diabetes mellitus in 6.8%,
musculoskeletal disease in 6.1%, and GI disease in 4.7%.
Respondents with a chronic condition were more likely to
report some problem on all EQ-5D dimensions and showed
lower mean EQ-5D index (Table 2). When specific chronic
conditions were considered (Table 3), significant
differences in the percentage of respondents reporting a problem
were observed in at least three dimensions (mobility, usual
activity, and pain/discomfort) for those with and without
the specific chronic conditions identified.
Population of Takamatsu City (2005)
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From the results of each level of the five dimensions in
Table 4, about 30% of respondents reported some pain/
discomfort and about 20% had anxiety/depression. A
‘‘moderate’’ problem on at least one dimension was
reported by 41.6% of respondents, whereas 4.0% of respondents
reported some form of ‘‘extreme’’ problem. Problems on
one or more EQ-5D dimensions were reported by 45.6% of
EQ-5D health state and SRH
The relationship between EQ-5D dimensions and SRH
status is presented in Table 5. These results show that, as
SRH decreases from very good to very poor, the
percentages of respondents reporting moderate or severe problems
increases in each of the five EQ-5D dimensions. In the
worst SRH category, over three-quarters of respondents
reported problems in each EQ-5D dimension except the
self-care dimension, while only 10.3% of respondents
reported problems on any of the five EQ-5D dimensions in
the best SRH category. Mean EQ-5D indices at each level
of SRH were all significantly different from each other and
decreased from very good (0.977) to very poor (0.537). The
Pearson correlation coefficient between SRH and the
EQ-5D index value was r = 0.568 (p \ 0.001).
Determinants influencing Japanese HRQOL
The results of multiple linear regression analyses for the
association between all social determinants and EQ-5D
score are shown in Table 6. Explanatory factors of social
background, health-related behaviors, and 11 chronic
conditions were entered into multiple regression analyses
as independent variables. HRQOL decreased with age.
Marital status and BMI were not associated with HRQOL.
Regarding employment status, unemployment/retirement
had a significantly negative impact on HRQOL.
Healthrelated behaviors, sufficient sleep (7–8 h/day), and having
a hobby exerted positive impacts, but feelings of severe
stress within the past month had a negative impact on
HRQOL. In terms of specific chronic conditions,
musculoskeletal and GI diseases showed significantly negative
impacts on HRQOL.
We attempted to describe HRQOL of the general population
of Takamatsu City in 2005, expressed in EQ-5D dimensions
and health state scores (mean EQ-5D index values).
Compared with a previous study in Japan by Ikeda et al. [
figures were higher on all EQ-5D dimensions. According to
other results from overseas (Table 7) [
2–5, 13, 16, 17
result resembled those from a UK study [
As mentioned, SRH is the most commonly used
singledimension measure for HRQOL in Japanese populations.
As SRH status decreased from very good to very poor, the
percentage of respondents reporting problems on any
EQ-5D dimension increased and mean EQ-5D index
decreased. This pattern again resembled those of studies in
other countries [
]. This study is the first to compare
SRH and EQ-5D index in Japan. An intermediate
correlation was identified between SRH and EQ-5D index
(r = 0.568; p \ 0.001).
This study also examined the relationship between
various factors and HRQOL using representative Japanese
samples. Consistent with past studies [
scores decreased with age. Regarding sex differences,
HRQOL tended to be lower in females than in males, but
not significantly so. In terms of employment status,
unemployment/retirement was associated with the lowest
Adjusting scores for age and sex by multiple linear
regression, age, unemployment/retirement, feelings of
severe stress within the past month, and musculoskeletal and
GI diseases were significantly associated with decreased
HRQOL score. Conversely, sufficient sleep (7–8 h/day) and
having a hobby were associated with increased HRQOL
This model in our study successfully explained 30% of
the variance in EQ-5D index scores. Conversely, BMI,
smoking, and alcohol intake were not associated with
Previous surveys of HRQOL and employment status
have reported that respondents who are retired or engaged
in housewife are more likely to report problems [
2, 13, 18
We were unable to find any significant association between
housewife or part-time employment and HRQOL, but
unemployment/retirement was significantly associated with
lower HRQOL in the general Japanese population. In
Japan, the unemployment rate was 4.4% in 2005 and
decreased to 3.9% in 2007. Labor participation rate was
almost 70% for working age (18–64 years), but decreased
to 19.4% by C65 years old [
]. About 90% of companies
in Japan adopt the retirement system, with retirement at
60 years old. Recently, participation of seniors in the
workforce has been reviewed, and there is strong demand
from seniors who want to work, so working expansion and
rehiring systems are gradually being introduced [
On the other hand, health-related behaviors such as
getting sufficient sleep (7–8 h/day) and having a hobby
exerted positive effects on HRQOL. According to recent
sleep research in Japan, individuals with sleep duration of
either \6 or [8 h tend to be more depressed than those
with sleep duration of 6–8 h [
]. As subjective sleep
sufficiency decreased, symptoms of depression increased,
indicating a linear, inverse-proportional relationship [
]. Having a hobby also had a significantly positive
impact on HRQOL. We were unable to find any previous
studies reporting a positive relationship between having a
hobby and HRQOL in a Japanese population. However,
according to past studies of the elderly in Japan, having a
hobby improves both care prevention and HRQOL in older
]. We also found that feelings of severe
stress significantly lowered HRQOL. Sources of severe
stress might differ for each age group. According to the
Comprehensive Survey of Living Conditions of the People
by the Ministry of Health, Labor, and Welfare 2004,
sources of stress for younger individuals (25–44 years)
included ‘‘income/family budget/debt’’ in 32.5%, ‘‘income
in the future or in old age’’ in 27.4%, ‘‘human relations
besides family’’ in 22.3%, and ‘‘work of self and spouse’’
in 21.9% . The middle-age group (45–64 years)
reported stress sources such as ‘‘income in the future or in
old age’’ in 39.3%, ‘‘own health/disease’’ in 36.7%, and
‘‘income/family budget/debt’’ in 26.5% [
‘‘own health/disease’’ in 60.4% and ‘‘self-care in old age’’
in 36.9% were the main sources of stress for the older age
group (C65 years) (not shown in table, [
Among the investigated chronic conditions,
musculoskeletal and GI diseases were significantly associated with
reduced HRQOL. In terms of reduced Japanese HRQOL
with musculoskeletal disease, 42.2 million (41.2%)
Japanese adults reportedly suffer from musculoskeletal
pain and 9.1 million (8.8%) might encounter interference
with daily activities due to pain [
]. Given this high
prevalence, musculoskeletal pain is a health problem that
warrants high priority in Japan.
In terms of the relationship between GI disease and
HRQOL of Japanese population, the
Domestic/International Gastroenterology Surveillance Study (DIGEST)
surveyed 5,581 respondents from 10 developed countries
(including Japan) and evaluated the impact of GI
symptoms on QOL [
]. This study showed that presence
of GI symptoms (especially upper GI symptoms) was
closely associated with impaired wellbeing and daily life in
According to the relation between other specific diseases
and HRQOL, a Swedish survey also reported that QOL was
lowest among individuals with depression (0.38) or low
back pain (0.66) using the EQ-5D [
], while depression and
arthritis showed the greatest decrements using EQ-5D
index scores in a US study [
Recent investigations have pointed out that Japanese
HRQOL might be affected by factors such as age, sex,
socioeconomic status, health-related behaviors, some
diseases, and social networks [
]. A previous study using
SRH in Japan revealed that female educational attainment
shows significant linear associations with SRH [
Adjusted household income was also significantly
associated with self-rated physical health among female
respondents. While educational attainment was associated with
SRH in the young age group, adjusted household income
was associated with self-rated physical health in the
middle-age and old-age groups [
]. Some previous studies
using SRH for elderly individuals in Japan have identified
that factors such as years of education, income, depression,
stress, sense of coherence, hobby activities, joining in
social activities, and getting social support are strongly
related to HRQOL [
23, 24, 34–37
]. More studies are
expected to investigate relationships between each factor
and Japanese HRQOL.
The present study has a number of limitations. As our
data were cross-sectional, no causal relationship may be
derived between sociodemographics, chronic conditions,
and HRQOL. Due to the limited number of response
categories in the EQ-5D for each question, a ceiling effect
may occur when measuring the health status of Japanese
samples. The data we collected included a slightly higher
proportion of data from the middle-age group than that in
the general population of Takamatsu City, and the
possibility therefore exists that the young age group is not
accurately reflected in the results. Our usable response rate
was low because we did not accept house-to-house
interviews, therefore those who answered this survey may be
more health conscious than the average in Takamatsu City.
In addition, we did not analyze some aspects of
socioeconomic status (education, household income), detailed
chronic conditions (e.g., depression), and social support as
factors of HRQOL. EQ-5D is a brief questionnaire and is
an effective tool to evaluate HRQOL of Japanese people.
Some Japanese surveys for specific diseases using EQ-5D
have been reported [
]. We hope to use EQ-5D with
other health survey questionnaires (e.g., Health Utility
Index, SF-12, and Quality of Well-Being) to gather more
data about HRQOL in Japanese populations.
Although the available information on HRQOL in Japanese
populations remains insufficient, this study furthers our
understanding of some important determinants influencing
Japanese HRQOL, using the EQ-5D. Our results also
resembled some findings from similar studies in other
countries. We hope to use EQ-5D with other health survey
questionnaires to gather more data about HRQOL of Japanese
Acknowledgments Takamatsu City and Kagawa University share
this data used in the present study. Takamatsu City also granted
permission to use the data for research.
Conflict of interest statement None declared.
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