1. 3rd Conference on Occupational Risk Prevention, Bilbao, 23-25 May 2012
High prevalence of depression among working people with occupational disease: a population-based study Carmen Otero Sierra1, Juan Miguel Macho-Fernandez2, Pedro R. Mondelo3, Nearkasen Chau4, Lorhandicap group4
1 Servicio de Prevención Hermanas Hospitalarias, Departamento de Organización de Empresas, Universitat Politècnica de Catalunya, Barcelona, Spain;
2 Servicio Angioradiología, Hospital Clinic, Barcelona, Spain;
3 (CERpIE) Research Centre for Corporate Excellence & Innovation, UPC (Technical University of Catalonia), Barcelona, Spain;
4 INSERM, U669, University Paris-Sud, University Paris Descartes, UMR-S0669, Paris, France.
Lorhandicap group: N Chau, F Guillemin, JF Ravaud, J Sanchez, S Guillaume, JP Michaely, C Otero Sierra, B Legras, A Dazord, M Choquet, L Méjean, N Tubiana-Rufi, JP Meyer, Y Schléret, JM Mur

2. 3rd Conference on Occupational Risk Prevention, Bilbao, 23-25 May 2012
Background
Occupational diseases (OD) are common:
‒ The ODs are common. Their prevalence have increased and was 9- fold higher in 2008 than in 1984 (Institut de recherche et documentation en économie de la santé, 2012)
‒ Prevalence of ODs with permanent disability strongly increase, 7-fold higher than in 2006 (Institut de recherche et documentation en économie de la santé, 2012)
‒ Most ODs are musculoskeletal disorders (MSDs) (Otero Sierra et al., Arch Mal Prof, 2000; Roquelaure et al., Arthritis & Rheumatism, 2006)
‒ A small proportion of occupational diseases have been recognized by the general compensation system (Otero Sierra et al., Arch Mal Prof, 2000).

3. 3rd Conference on Occupational Risk Prevention, Bilbao, 23-25 May 2012
Background
Mental disorders are common:
‒ 450 millions people worldwide (Hosman et al., WHO report 2004)
‒ 83 millions adults (18-65 yr, 27%) in European Union
(Wittchen & Jacob, Eur Neuropharmacol 2005)
‒ Depressive symptoms affect 23% of men and 31% of women (12-75 yr) in France (Beck et al., Paris: INPES, 2007)
‒ They represent 10% of total health care expediture, with direct & indirect costs higher than cancer and diabetes (Fondation Fondamental 2011)
‒ They relate to unhealthy behaviours and disability, and may become the most frequent cause of disability worldwide by 2030 (Penninx et al., Arch gen Psychiatry 1999; Harvey et al., Neuroimage, 2005; Khlat et al., Scand J Public Health 2010 ; WHO 2010; Chau et al., J Occup Envion Med 2011).
‒ MSDs are associated with depression and cognitive disability, more strongly among manual workers, service workers, and clerks (Khlat et al., Scand J Public Health, 2010).

4. 3rd Conference on Occupational Risk Prevention, Bilbao, 23-25 May 2012
Background
Hypotheses:
‒ Recognized ODs are relatively rare and recognition is rather late.
‒ When recognized, physical/mental comorbidity and disabilities may be established.
‒ The issues may be higher among people at work because of job demands and altered health.
‒ Those issues may explain the steady increase of mortality of workers with OD in the last decade (Institut de recherche et documentation en économie de la santé, 2012).
‒ Appropriate prevention should be sooner. Health monitoring may be made by occupational and general physicians as workers with ODs are confident on them (Otero Sierra et al., Arch Mal Prof, 2000).

5. 3rd Conference on Occupational Risk Prevention, Bilbao, 23-25 May 2012
Objectives
To explore, using population-based studies, the depression risk for workers with recognized OD compared with the general population from the same geographical area for: ‒ Working subjects, ‒ Inactive subjects. Indeed, we postulate that occupational demands continue to play a role in depression among people at work, and less in inactive people. We further explored whether people with OD suffer from comorbidity (chronic diseases) and disability that may increase the depression risk.

6. 3rd Conference on Occupational Risk Prevention, Bilbao, 23-25 May 2012
Methods
Study sample:
727 subjects from the general compensation system (17 million workers in France) with recognized OD for a two-year period in north-eastern France (Lorraine).
Participation rate: 79% (mails lost for 14 subjects).
560 subjects filled in a questionnaire.
Reference group:
Subjects aged 15+ years living in 8,000 randomly selected households (with telephone) in north-eastern France (Lorraine, 1/100 of the population).
6,234 subjects filled in a questionnaire (participation rate 44.3%).
4,766 subjects retained for analysis (having worked at the time of survey).

7. 3rd Conference on Occupational Risk Prevention, Bilbao, 23-25 May 2012
Methods
Study protocol
Study sample:
3 sending of self-administered questionnaires mailed at 1-month interval
(with a covering letter and a pre-paid envelope for the reply).
Reference group:
An application to participate and 3 sendings of self-administered questionnaires at 1-month intervals (with a covering letter and a pre-paid envelope for the reply).
The investigation was approved by the national review board (CNIL).
Written informed consent from respondents.

8. 3rd Conference on Occupational Risk Prevention, Bilbao, 23-25 May 2012
Methods
Questionnaire
Study sample:
It covered socioeconomic characteristics, job characteristics, health, physician-diagnosed-diseases including depression, and disabilities.
5 occupational categories were considered: professionals/managers; craftsmen/tradesmen/farmers/heads of firm; intermediate professionals; service workers/clerks; and manual workers
(Because of small number of subjects, the 3 first groups were grouped).
Reference group:
The questionnaire covered sex, birth date, educational level, marital status, job characteristics, working conditions, health status, physician- diagnosed-diseases including depression, and disabilities.

9. 3rd Conference on Occupational Risk Prevention, Bilbao, 23-25 May 2012
Statistical analysis
First, we compared the characteristics of the study sample with OD and the reference group using the Chi2 test.
Then, we computed the depression risk for the study sample compared with reference group, for working and inactive people separately, using:
‒ Crude odds ratio,
‒ Sex-age-adjusted odds ratio (ORsa),
‒ Sex-age-occupation-adjusted odds ratio (ORsao).
The contribution of occupation (%) to the depression risk was defined by
(ORsa – ORsao)/(ORsao – 1).
Finally, the associations between depression and subjects’ characteristics (including diseases) among working people with OD were assessed using the ORsa.
STATA software (Stata, College Station, TX, USA) was used.

10. 3rd Conference on Occupational Risk Prevention, Bilbao, 23-25 May 2012
Results
Table 1. Characteristics of the study sample with occupational diseases and the reference group: %
Study sample
(N=560)
Reference group
(N=4,766)
p-value
Men
49.0
51.0
0.078
Age (yr)
<0.001
<45
25.7
51.4
45-54
33.6
16.3
55-64
27.1
13.7
65 or over
13.6
18.5
Occupation
Manual workers
73.7
23.8
Service workers/clerks
18.4
36.5
Others
7.9
39.7
Occupational status
Working
87.5
56.8
Inactive
12.5
43.2
Bad health status
70.9
42.8
Chronic diseases
Depression
4.8
3.6
0.137
Infectious disease
13.4 ─
Cancer
2.1
2.4
0.714
Nervous-system disease
1.8
5.2
Deafness
14.8
Cardio-vascular disease
16.8
20.3
0.051
“─”: not available.

11. 3rd Conference on Occupational Risk Prevention, Bilbao, 23-25 May 2012
Results
Table 1. Characteristics of the study sample with occupational diseases and the reference group: % - continued
Study sample
(N=560)
Reference groupa
(N=4,766)
p-value
Respiratory disease
16.4
9.6
<0.001
Asbestos
4.5 ─
Others
13.4
Genitourinary disease
1.4
3.2
0.021
Musculoskeletal disorders
71.2
52.0
Osteoarthritis
30.4
Carpal tunnel
33.0
3.0
Scoliosis and cyphosis
6.4
10.5
0.002
Tendinitis, tenosynovitis, and epicondylitis
46.6
8.4
Other diseases
15.0
19.2
0.015
Number of diseases
0-1
37.9
58.6
2-4
48.4
32.6
5 or over
13.7
8.8
Disabilities
69.1
Occupational activity
59.5
Domestic activity
51.1
26.4
Leisure activity
46.4
“─”: not available.

12. 3rd Conference on Occupational Risk Prevention, Bilbao, 23-25 May 2012
Results
Table 2. Prevalence and risk of depression among the subjects with occupational diseases and for the reference group: %, odds ratios and 95% CI
Reference groupa
Study sample
p-value
Working people
Number of subjects
2,709
490
Frequency of depression (%)
2.6
4.9
0.006
Crude odds ratio
1.00
1.94**
Sex-age-adjusted odds ratio
1.94*
Sex-age-occupation-adjusted odds ratio
1.54a
Inactive people
2,057 70
4.3
0.825
*p<0.05, **p<0.01.
a The contribution (%) of occupation to the depression risk was ( )/(1.94-1)=43%.

13. 3rd Conference on Occupational Risk Prevention, Bilbao, 23-25 May 2012
Results
Table 3. Associations between depression and subjects’ characteristics among working people with occupational diseases (N=490): Sex-age-adjusted odds ratio and 95% CI N %
OR 95% CI
Sex
Men
238
2.5
1.00
Women
251
7.2
3.40*
Bad health status No
147
1.4
Yes
343
6.4
4.93*
Number of diseases 1
179
1.1
2-4
245
6.5
5.33*
5 or over 66
9.1
8.27*
Disability for occupational activity
186
3.2
304
5.9
Disability for domestic/leisure activity
219
2.3
271
7.0
2.88*
*p<0.05, **p<0.01.
N: number of subjects.

14. 3rd Conference on Occupational Risk Prevention, Bilbao, 23-25 May 2012
Results
Table 3. Associations between depression and subjects’ characteristics among working people with occupational diseases (N=490) - Continued N %
OR 95% CI
Job adjusted because of diseases No
284
2.8
1.00
Yes
206
7.8
2.71*
Time-schedule adjusted because of diseases
326
3.7
164
7.3
Aid of colleagues for demanding tasks
244
4.5
246
5.3
Diploma
Higher than primary school
253
Primary school
237
7.2
Opinion for occupational disease declaration procedure
Acceptable, convenient, no opinion
323
4.3
Complicated
167
6.0
*p<0.05, **p<0.01.
N: number of subjects.

15. 3rd Conference on Occupational Risk Prevention, Bilbao, 23-25 May 2012
Results
Table 4. Associations between depression and diseases among working people with occupational diseases (N=490): Sex-age-adjusted odds ratio and 95% CI
Odds ratio
95% CI
Infectious disease
1.03
Cancer
Indeterminate
Nervous-system disease
7.98*
Deafness
1.74
Cardio-vascular disease
1.60
Respiratory disease
Asbestos
13.64**
Others
1.21
Genitourinary disease
9.09*
Musculoskeletal disorders
Osteoarthritis
2.57*
Carpal tunnel
3.56**
Scoliosis and cyphosis
2.42
Tendinitis, tenosynovitis, epicondylitis
1.11
0.76
1.63
*p<0.05, **p<0.01.

16. 3rd Conference on Occupational Risk Prevention, Bilbao, 23-25 May 2012
Conclusion
Recognized occupational diseases were strongly associated with depression among workers remaining at work.
Most of these workers experienced a number of chronic diseases, difficulties for occupational, domestic and leisure activities, which were strongly related to depression.
Women were more affected by depression than men.
Occupational diseases were too tardily appropriately treated.
Prevention should be taken early to limit occupational exposures, occurring of diseases, and evolution to disabilities.
Health monitoring of working individuals with OD is needed. They are generally confident in general and occupational physicians (Otero Sierra et al., Arch Mal Prof, 2000).