Prevalence and changes in chronic diseases among South Korean farmers: 1998 to 2005.

Abstract

Epidemiologic studies have suggested a unique pattern of disease among farmers in Western countries, but limited information is available about the magnitude of disease prevalence and their changes over time in Asian farmers. The aim of this study was to compare the prevalence and changes in chronic diseases among farmers with those of other occupational groups in South Korea.
Using data from three consecutive cross-sectional national surveys: the Korean National Health and Nutrition Examination Survey 1998 (n = 39,060), 2001 (n = 37,769), and 2005 (n = 34,145), we calculated age and gender-standardized prevalence of chronic diseases by the direct method and compared the prevalence changes from 1998 to 2005.
Female farmers had significantly higher chronic disease prevalence than other occupational groups in all three surveys. Arthritis was the most prevalent chronic disease among farmers for both men and women. Compared with other populations, farmers demonstrated a higher prevalence of arthritis and intervertebral disc disorders. Farmers showed higher prevalence changes for intervertebral disc disorders than other occupational workers.
Our findings support that South Korean farmers have a distinct pattern of diseases prevalence from other populations. More detailed studies investigating the risk of musculoskeletal diseases and intensive intervention efforts to reduce the prevalence these diseases, particularly among female farmers, are required.

Full text

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BioMed Central
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BMC Public Health
Open Access
Research article
Prevalence and changes in chronic diseases among South Korean
farmers: 1998 to 2005
Eun Shil Cha, Kyoung Ae Kong, Eun Kyeong Moon and Won Jin Lee*
Address: Department of Preventive Medicine, College of Medicine, Graduate School of Public Health, Korea University, Seoul, Korea
Email: Eun Shil Cha - eunshiri83@korea.ac.kr; Kyoung Ae Kong - joy-well@hanmail.net; Eun Kyeong Moon - mek9980@korea.ac.kr;
Won Jin Lee* - leewj@korea.ac.kr
* Corresponding author
Abstract
Background: Epidemiologic studies have suggested a unique pattern of disease among farmers in
Western countries, but limited information is available about the magnitude of disease prevalence
and their changes over time in Asian farmers. The aim of this study was to compare the prevalence
and changes in chronic diseases among farmers with those of other occupational groups in South
Korea.
Methods: Using data from three consecutive cross-sectional national surveys: the Korean
National Health and Nutrition Examination Survey 1998 (n = 39,060), 2001 (n = 37,769), and 2005
(n = 34,145), we calculated age and gender-standardized prevalence of chronic diseases by the
direct method and compared the prevalence changes from 1998 to 2005.
Results: Female farmers had significantly higher chronic disease prevalence than other
occupational groups in all three surveys. Arthritis was the most prevalent chronic disease among
farmers for both men and women. Compared with other populations, farmers demonstrated a
higher prevalence of arthritis and intervertebral disc disorders. Farmers showed higher prevalence
changes for intervertebral disc disorders than other occupational workers.
Conclusion: Our findings support that South Korean farmers have a distinct pattern of diseases
prevalence from other populations. More detailed studies investigating the risk of musculoskeletal
diseases and intensive intervention efforts to reduce the prevalence these diseases, particularly
among female farmers, are required.
Background
With over one billion workers, agriculture accounted for
nearly 35% of worldwide employment [1]. A number of
studies have suggested a unique pattern of morbidity and
mortality among farmers [2-4]. Farmers have a remarka-
ble deficit in total mortality, cardiovascular diseases, dia-
betes mellitus, psychiatric disorders and total cancer
compared with the other populations, but appear to have
higher prevalence rates of musculoskeletal diseases, respi-
ratory diseases, hearing loss, skin disorders, accidental
death and cancer of the skin, stomach, brain, and prostate,
as well as the nervous, lymphohematopoietic systems
[2,3,5,6].
Farming as an occupation has a number of unique charac-
teristics compared to other occupations, such as worker
Published: 29 July 2009
BMC Public Health 2009, 9:268doi:10.1186/1471-2458-9-268
Received: 17 March 2009
Accepted: 29 July 2009
This article is available from: http://www.biomedcentral.com/1471-2458/9/268
© 2009 Cha et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0),
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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traits and behavior, the work setting, and organizational
structure [7]. Farming is not organized to provide workers
with safety regulations or stable and flexible finances [8].
Farmers are further exposed to a wide range of occupa-
tional hazards such as ergonomic stresses, sunlight,
viruses, inorganic dust, and pesticides [9].
Most previous investigations on farmers, however, have
been conducted in the United States and Western Europe;
so much less is known about the health status of farmers
in Asian populations. Environmental and lifestyle factors
for disease prevalence among farmers are likely to vary
between countries. Although South Korea has tradition-
ally been an agricultural country and retains a farm popu-
lation exceeding 3.2 million people [10], few
epidemiologic studies have focused on the farm sector.
Most available epidemiologic studies on farmers in South
Korea were focused on specific regions or symptoms, and
did not estimate disease prevalence among the entire farm
population. In addition, interpretation of these findings is
limited due to the lack of an appropriate reference popu-
lation [11].
This study, therefore, aimed to investigate chronic disease
prevalence among farmers compared to other popula-
tions and relevant changes from 1998 to 2005 in order to
identify major health issues among farmers in South
Korea.
Methods
Measurement
The data used in this study was drawn from the 1998,
2001, and 2005 Korean National Health and Nutrition
Examination Surveys (KNHNES). The KNHNES was a
cross-sectional and nationally representative survey con-
ducted by the Korean Ministry of Health and Welfare. The
objective of the KNHNES is to estimate representative
nationwide data about health status, utilization of health
care and health-related behaviors and to provide a base
for an effective health promotion program. In this survey,
trained interviewers visited subjects' homes and adminis-
tered a standardized questionnaire on the demographics,
socioeconomic status, utilization of health care resources
and medical history of each respondent. The target popu-
lation of this survey included all non-institutionalized
civilian South Korean individuals. The survey employed a
stratified multistage probability sampling design, and the
subjects were selected from sampling units predicated by
geographical area, gender and age, as determined by
household registries. The overall response rates of the
Korean National Health and Nutrition Examination Sur-
vey were 90.8% in 1998, 92.3% in 2001, and 89.9% in
2005, respectively [12].
Participants were considered to have a chronic disease if
they answered "yes" to both of these interview questions:
"Have you experienced any chronic diseases in the preced-
ing 12 months?" and "Have you been diagnosed with the
disease by a physician?" Chronic diseases were defined as
diseases lasting at least three months. Overall prevalence
of chronic diseases in this study was defined by having
any chronic disease except dental diseases. Individual
chronic diseases were selected based on a priori interest in
farmer's health and in having a sufficient number of cases
for all three surveys. They included arthritis, intervertebral
disc disorders, hypertension, chronic lung diseases,
asthma, cancer, diabetes mellitus, and cataract/glaucoma.
Study population
The total numbers of KNHNES participants were 39,060
(19,038 men and 20,022 women) in 1998, 37,769
(18,442 men and 19,327 women) in 2001, and 34,145
(16,356 men and 17,789 women) in 2005, respectively.
We divided the total participants into three occupational
groups of self-reported farmers, manual workers, and
non-manual workers, based on the Korea standard classi-
fication of occupation [13]. The category of farmers
including about 4.4% fishery and 0.2% forestry workers
[10]. Manual workers included craft and related trades
workers, plant/machine operators and assemblers, and
elementary occupations, while non-manual workers
included legislators, senior officials and managers, profes-
sionals, technicians and associate professionals, clerks,
service workers and sale workers. We restricted the sub-
jects to those aged 20 or more to examine prevalent
chronic diseases and for comparison with working-age
population. Through this, we investigated a 1998 popula-
tion of 27,201 including 3,639 farmers, 4,677 manual
and 8,101 non-manual workers, a 2001 population of
26,785 including 1,714 farmers, 4,996 manual and 9,193
non-manual workers, and a 2005 population of 25,161
including 1,732 farmers, 4,966 manual and 8,358 non-
manual workers in the analysis.
Statistical analysis
For all surveys, sampling weights were applied to account
for unequal probabilities of selection resulting from the
sample design, and from nonresponse, and to adjust for
post-stratification population totals. Standard errors were
calculated using Taylor series linearization method to
account for the sampling design and to apply survey
weight. Statistical analyses were carried out using Stata
10.0 (StataCorp., College Station, Texas). For compari-
sons across surveys, the age-standardized prevalence with
95% confidence intervals of chronic diseases was calcu-
lated using the direct adjustment method by 2005 stand-
ard population, with a population breakdown by five-year
increments from the Korea National Statistical Office
[10]. This analysis was performed separately for each of

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the three surveys and for gender. Differences in prevalence
over time according to occupational groups were based on
comparison of data from 2005 with 1998 data. This study
analyzed publicly available data sets and was therefore
exempt from institutional review board approval.
Results
Table 1 illustrates the selected characteristics of the study
subjects by occupational groups and the three surveys.
Farmers were more likely than other occupational groups
and the total population to be older, married, residing in
rural areas, less educated, and collecting a lower income.
Farmers and non-manual workers included a higher
number of females than manual workers. Farmers were
less often current smokers and drinkers of alcohol than
other populations. Farmers had less frequent medical
check-ups than other groups in 1998 and 2001, but not in
2005.
The age-standardized prevalence of overall chronic dis-
ease and health service utilization by occupation accord-
ing to the three calendar years are presented in Table 2.
Female farmers reported significantly higher prevalence of
doctor-diagnosed overall chronic diseases than other
occupational groups and the total population, whereas
male farmers showed a decreasing trend in prevalence of
chronic diseases. Female farmers were less likely to report
their general health as "good to excellent" than other
groups. The numbers of doctor visits during the previous
two weeks and reported hospitalizations were greater
among female farmers than other groups in 2005.
Table 3 and 4 show selected chronic disease prevalence by
occupational groups in men and women, respectively.
The most prevalent diseases among farmers were arthritis,
intervertebral disc disorders, and hypertension. Com-
pared to other occupational groups and the total popula-
tion, farmers had higher prevalence of arthritis and
intervertebral disc disorders in both men and women,
whereas male farmers had lower prevalence of hyperten-
sion and diabetes mellitus. Intervertebral disc disorders
increased in all three occupational groups between 1998
and 2005, however, farmers had higher prevalence
changes than other occupational groups during the study
period.
Discussion
Using data from nationally representative samples of the
South Korean population, we found that female farmers
had a higher prevalence of overall chronic disease than
other occupational groups, or the total population. Arthri-
tis and intervertebral disc disorders were the most preva-
lent chronic diseases among farmers, and the increase in
the prevalence of intervertebral disc disorders over time
was greater among farmers than other groups.
The pronounced elevated prevalence of chronic diseases
among women was consistent with previous findings.
Female farmers from Finland have been reported to suffer
more chronic diseases than female blue- and white-collar
workers whereas male farmers' self-reported morbidity
was on a par with that of other workers [14]. Female farm-
ers were also more likely to poses higher rates of asthma,
depression [15] and cancer of the lymphatic and hemat-
opoietic system [2] than men in the US. Variances
between male and female farmers indicate that lifestyle
may be of different significance for the two genders.
Women on farms may carry additional burdens associated
with financial hardship, heavy seasonal workloads, expo-
sure to chemicals, and experience employment off the
farm, which may additionally contribute to the differ-
ences of disease prevalence between men and women
[16,17].
High prevalence of arthritis and intervertebral disc disor-
ders in farmers is consistent with previous studies that
have indicated that farmers have higher rates of muscu-
loskeletal diseases than other populations [18,19].
Numerous physical risk factors are integral to farming,
such as high workloads, heavy lifting, bending and twist-
ing, exposure to vibration from farm equipment, and per-
forming tasks while in awkward postures [19]. These have
been associated with an increased risk of acquiring musc-
uloskeletal diseases such as osteoarthritis [20], low back
pain [21,22], and neck and upper limb complaints [23].
The prevalence of musculoskeletal diseases and osteoar-
thritis among farmers were reported to be also higher than
in other occupational groups in South Korea [24]. The
increasing prevalence of arthritis and intervertebral disc
disorders in farmers could also in part be explained by
increased medical check-ups.
We found hypertension to be among the most prevalent
diseases for farmers but the magnitudes of prevalence was
lower than for other groups and the change of prevalence
was also identified as the smallest among male farmers.
These findings are consistent with other studies demon-
strating that the prevalence of hypertension and associ-
ated risk factors are higher in urban than in rural areas
[25,26]. In South Korea, the prevalence of hypertension
for both genders was also reported to be higher in urban
areas [27]. These prevalence differences between farmers
and other groups may be related to the distribution of life-
style factors [28]. In this study, farmers smoke less tobacco
and drink less alcohol than other occupational groups
(Table 1).
A slightly higher prevalence of chronic lung diseases was
seen in male farmers than in other occupational groups
and the total population. Previous studies have shown
that farmers are exposed to a variety of inhaled agents

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Table 1: Characteristics of participants aged 20 and older by occupational groups in three Korean National Health and Nutrition Examination Surveys
1998 20012005
FarmersManual Non-manualTotala
FarmersManualNon-manual TotalFarmers ManualNon-manual Total
(n = 3,639)(n = 4,677)(n = 8,101) (n = 27,201) (n = 1,714)(n = 4,996) (n = 9,193) (n = 26,785)(n = 1,732)(n = 4,966) (n = 8,358) (n = 25,161)
Sex
Men
Women
Age (years)
Educational level
 Elementary
Middle
High
 University
Marital status
Single
Married
Others
1,844 (50.7)
1,795 (49.3)
55.3 ± 12.2
3,364 (71.9)
1,313 (28.1)
41.9 ± 11.3
4,649 (57.4)
3,452 (42.6)
37.7 ± 10.6
12,853 (47.3)
14,348 (52.8)
44.0 ± 15.7
894 (52.2)
820 (47.8)
57.6 ± 11.4
3,642 (72.9)
1,354 (27.1)
43.1 ± 11.1
5,149 (56.0)
4,044 (44.0)
38.4 ± 10.8
12,615 (47.1)
14,170 (52.9)
44.0 ± 15.5
905 (52.3)
827 (47.8)
59.4 ± 11.0
3,492 (70.3)
1,474 (29.7)
45.2 ± 11.5
4,478 (53.6)
3,880 (46.4)
39.1 ± 11.0
11,722 (46.6)
13,439 (53.4)
45.7 ± 15.8
2,450 (67.3)
577 (15.9)
544 (15.0)
68 (1.9)
1,191 (25.5)
1,056 (22.6)
2,156 (46.1)
274 (5.9)
623 (7.7)
742 (9.2)
3,287 (40.6)
3,449 (42.6)
7,729 (28.4)
3,705 (13.6)
9,572 (35.2)
6,195 (22.8)
1,151 (67.2)
293 (17.1)
227 (13.3)
42 (2.5)
994 (19.9)
1,031 (20.7)
2,456 (49.2)
507 (10.2)
544 (5.9)
700 (7.6)
3,540 (38.6)
4,387 (47.8)
5,837 (21.8)
3,285 (12.3)
9,820 (36.7)
7,790 (29.1)
1,103 (63.7)
300 (17.3)
274 (15.8)
55 (3.2)
997 (20.1)
924 (18.6)
2,479 (50.0)
562 (11.3)
420 (5.0)
514 (6.2)
2,833 (33.9)
4,589 (54.9)
5,561 (22.1)
2,873 (11.4)
8,618 (34.3)
8,081 (32.2)
101 (2.8)
3,139 (86.3)
399 (11.0)
646 (13.8)
3,625 (77.5)
406 (8.7)
1,689 (20.9)
6,080 (75.1)
332 (4.1)
4,499 (16.5)
19,645 (72.2)
3,057 (11.2)
34 (2.0)643 (12.9)
3,829 (76.6)
524 (10.5)
2,116 (23.0)
6,608 (71.9)
467 (5.1)
4,791 (17.9)
18,952 (70.8)
39 (2.3) 663 (13.4)
3,683 (74.2)
619 (12.5)
2,120 (25.4)
5,689 (68.1)
549 (6.6)
4,657 (18.5)
17,212 (68.5)
3,266 (13.0)
1,489 (86.9)
190 (11.1)
1,480 (85.5)
213 (12.3)3,036
(11.3)
Incomeb
Area
Rural
Urban
Smoking statusc
Never
Former
Current
Alcohol consumption frequencyc
None
 2/week
 3/week
Medical check-upc
(past 2 years)
Yes
No
85.3 ± 83.7 127.4 ± 79.8 177.3 ± 110.3132.2 ± 101.7 105.3 ± 77.2163.6 ± 93.2227.9 ± 132.0180.1 ± 123.5 155.4 ± 140.5210.2 ± 125.7 305.7 ± 176.1234.8 ± 165.8
3,390 (93.2)
249 (6.8)
1,354 (29.0)
3,323 (71.1)
1,650 (20.4)
6,451 (79.6)
9,520 (35.0)
17,681 (65.0)
1,564 (91.3)
150 (8.8)
890 (17.8)
4,106 (82.2)
1,216 (13.2)
7,977 (86.8)
5,639 (21.1)
21,146 (79.0)
1,497 (86.4)
235 (13.6)
858 (17.3)
4,108 (82.7)
937 (11.2)
7,421 (88.8)
4,964 (19.7)
20,197 (80.3)
681 (55.6)
130 (10.6)
414 (33.8)
598 (37.7)
164 (10.3)
825 (52.0)
1,343 (50.6)
239 (9.0)
1,075 (40.5)
4,965 (56.3)
776 (8.8)
3,082 (34.9)
237 (55.8)
45 (10.6)
143 (33.7)
572 (40.1)
150 (10.5)
706 (49.4)
1,531 (53.8)
274 (9.6)
1,038 (36.5)
4,762 (60.1)
710 (9.0)
2,449 (30.9)
264 (52.9)
117 (23.5)
118 (23.7)
579 (36.4)
296 (18.6)
716 (45.0)
1,414 (53.5)
467 (17.7)
763 (28.9)
4,354 (56.6)
1,271 (16.5)
2,069 (26.9)
560 (45.7)
334 (27.3)
331 (27.0)
371 (23.4)
717 (45.2)
499 (31.4)
630 (23.7)
1,310 (49.3)
717 (27.0)
2,952 (33.5)
3,875 (43.9)
1,996 (22.6)
236 (55.9)
106 (25.1)
80 (19.0)
546 (38.5)
589 (41.5)
285 (20.1)
1,152 (40.7)
1,291 (45.6)
391 (13.8)
3,975 (50.4)
2,923 (37.1)
982 (12.5)
279 (55.9)
98 (19.6)
122 (24.5)
566 (35.6)
644 (40.5)
381 (24.0)
1,031 (39.0)
1,214 (45.9)
399 (15.1)
3,718 (48.3)
2,829 (36.8)
1,147 (14.9)
533 (43.5)
692 (56.5)
859 (54.1)
728 (45.9)
1,599 (60.2)
1,058 (39.8)
4,268 (48.4)
4,555 (51.6)
195 (45.9)
230 (54.1)
754 (52.9)
671 (47.1)
1,581 (55.6)
1.262 (44.4)
3,799 (48.0)
4,116 (52.0)
282 (56.5)
217 (43.5)
848 (53.3)
742 (46.7)
1,520 (57.5)
1,124 (42.5)
3.906 (50.8)
3,787 (49.2)
Data were number (%) or mean ± SD
aTotal population included farmers, manual workers, non-manual workers, and others
bUnit is 10 thousand Korean won/month
cOnly a third of total participants had these information

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Table 2: Age-standardized prevalence of chronic diseases and health service utilization by occupational groups and gender in three
Korean National Health and Nutrition Examination Surveys
199820012005
Cases ASP (95%CI)a
Cases ASP (95% CI)Cases ASP (95% CI) Change (95% CI)b
Men
Overall chronic diseasesc
Farmers
Manual
Non-manual
Totald
1,029
1,064
1,294
4,634
37.4 (34.1, 40.8)
33.6 (31.4, 35.9)
30.5 (28.5, 32.5)
34.6 (33.3, 35.9)
533
1,209
1,532
4,585
35.2 (32.1, 38.5)
34.4 (32.2, 36.7)
33.3 (31.4, 35.2)
35.4 (34.4, 36.5)
506
1,362
1,503
4,799
34.8 (29.6, 40.5)
39.1 (37.1, 41.1)
37.1 (35.3, 38.9)
38.2 (37.2, 39.2)
-2.6 (-8.6, 3.6)
5.5 (2.5, 8.5)
6.6 (3.9, 9.3)
3.6 (2.0, 5.3)
Self-rated health "good to excellent"
Farmers
Manual
Non-manual
Total
252
513
758
1,916
42.7 (35.7, 45.0)
45.8 (42.4, 49.2)
50.8 (47.3, 54.3)
46.6 (44.9, 48.3)
89
498
855
1,784
62.3 (55.6, 68.5)
50.3 (46.9, 53.7)
55.2 (52.2, 58.1)
50.5 (48.7, 52.4)
312
1,709
2,624
5,825
57.7 (51.4, 63.8)
51.2 (49.1, 53.3)
58.0 (56.0, 60.0)
52.7 (51.6, 53.9)
15.0 (5.4, 24.7)
5.4 (1.3, 9.5)
7.2 (3.2, 11.2)
6.1 (4.0, 8.2)
Doctor visits (past 2 weeks)
Farmers
Manual
Non-manual
Total
592
819
1,035
3,212
25.4 (22.2, 28.8)
25.5 (23.5, 27.6)
23.1 (21.3, 25.1)
24.7 (23.7, 25.6)
276
573
639
2,164
20.5 (15.9, 26.1)
16.3 (14.9, 17.9)
15.1 (13.6, 16.7)
16.7 (16.0, 17.4)
326
705
841
2,723
29.5 (22.3, 37.8)
21.3 (19.7, 23.0)
21.0 (19.4, 22.7)
21.5 (20.7, 22.4)
4.1 (-3.1, 11.3)
-4.2 (-6.9, -1.6)
-2.1 (-4.6, 0.3)
-3.2 (-4.4, -1.9)
Hospitalizations (past 12 months)
Farmers
Manual
Non-manual
Total
146
150
162
668
6.2 (4.7, 8.3)
4.7 (3.8, 5.7)
3.6 (2.9, 4.5)
4.9 (4.5, 5.4)
50 7.0 (4.4, 11.1)
4.4 (3.4, 5.8)
3.5 (2.7, 4.6)
4.2 (3.8, 4.5)
106
307
261
1,031
6.8 (5.2, 8.8)
9.8 (8.3, 11.5)
6.1 (5.2, 7.1)
8.5 (7.9, 9.1)
0.6 (-2.2, 3.4)
5.1 (3.3, 7.0)
2.5 (1.2, 3.6)
3.6 (2.8, 4.2)
138
154
539
Women
Overall chronic diseases
Farmers
Manual
Non-manual
Total
1,306
623
1,093
6,934
52.7 (49.6, 55.8)
43.9 (40.8, 47.0)
41.3 (39.0, 43.6)
46.9 (45.7, 48.2)
610
669
1,312
6,548
57.4 (53.6, 61.0)
48.9 (46.1, 51.8)
43.5 (41.7, 45.2)
46.4 (45.5, 47.4)
622
787
1,433
7,029
61.3 (50.1, 71.5)
51.4 (48.1, 54.6)
48.0 (46.3, 49.7)
50.4 (49.5, 51.4)
8.6 (0.1, 17.2)
7.5 (3.0, 12.0)
6.7 (3.9, 9.6)
3.5 (1.9, 5.0)
Self-rated health "good to excellent"
Farmers
Manual
Non-manual
Total
200
190
514
1,801
37.9 (32.1, 44.0)
41.8 (36.4, 47.5)
45.5 (41.9, 49.1)
38.4 (36.7, 40.0)
5339.2 (29.3, 50.1)
37.3 (31.7, 43.2)
44.1 (41.0, 47.3)
39.8 (38.0, 41.6)
144
481
1,993
5,158
28.7 (19.5, 40.2)
35.1 (31.7, 38.7)
45.8 (43.5, 48.1)
40.3 (39.3, 41.3)
-9.2 (-22.2, 3.9)
-6.7 (-13.7, 0.3)
0.3 (-4.3, 5.0)
1.9 (-0.0, 3.9)
139
601
1,696
Doctor visits (past 2 weeks)
Farmers
Manual
Non-manual
Total
Hospitalizations (past 12 months)
Farmers
Manual
Non-manual
Total
718
485
1,015
4,939
32.9 (29.1, 37.0)
33.4 (30.6, 36.3)
35.7 (33.0, 38.5)
34.0 (32.9, 35.1)
299
377
722
3,486
23.6 (19.7, 27.9)
27.3 (24.4, 30.4)
23.4 (20.5, 26.5)
24.6 (23.8, 25.4)
395
453
920
4,356
40.5 (33.2, 48.2)
28.7 (25.8, 31.9)
30.2 (28.0, 32.5)
31.5 (30.6, 32.4)
7.6 (-0.1, 15.3)
-4.7 (-8.8, -0.4)
-5.5 (-9.0, -1.9)
-2.5 (-3.9, -1.1)
96
41
6.7 (4.5, 10.0)
3.3 (2.3, 4.6)
5.3 (4.4, 6.5)
7.9 (7.4, 8.4)
44
36
99
493
3.8 (2.3, 6.2)
1.7 (1.2, 2.4)
4.0 (2.4, 6.6)
3.5 (3.2, 3.9)
83
112
258
1,423
16.2 (14.5, 18.0)
7.0 (5.6, 8.8)
8.4 (6.6, 10.6)
10.6 (10.0, 11.2)
9.5 (5.2, 13.6)
3.7 (1.7, 5.7)
3.1 (0.8, 5.4)
2.7 (1.9, 3.5)
202
1,133
aAge-standardized prevalence and 95% confidence intervals
bPrevalence change from 1998 to 2005 and 95% confidence intervals
cOverall prevalence of chronic diseases was defined to be any chronic disease except dental diseases
dTotal population included farmers, manual workers, non-manual workers, and others