[Prevalence of asthma among adults in France, data from the Constances cohort study]. / Prévalence de l'asthme chez l'adulte en France, données de la cohorte Constances.

INTRODUCTION: The objectives of our study were to estimate the prevalence of asthma in adults in France and to study the effects of gender on the associations of asthma with the corpulence and socio-economic characteristics of individuals. METHODS: We estimated the prevalence of current asthma (asthma attack in the past 12 months or current treatment for asthma) from data collected at inclusion in the Constances cohort study in 2013-2014. Analyses were performed separately in men and women, using robust Poisson regression for multivariate analysis. RESULTS: Using data from 34,100 participants in the cohort (men: 47.7 %; mean age: 44.6 years), the prevalence of current asthma was estimated to be 5.8 % (5.1 % in men, 6.4 % in women). The risk of asthma was increased in women with high body mass index (BMI) or waist circumference. In men, only a high waist circumference was associated with an increased risk of asthma. An association with low socioeconomic status was observed only among women. CONCLUSION: The associations of asthma with corpulence and socioeconomic status differed between men and women. Additional analyses should provide a better understanding of the mechanisms responsible for these differences.

[Asthma and socioeconomic characteristics in France in 2012]. / Asthme et caractéristiques socioprofessionnelles en France en 2012.

INTRODUCTION: The prevalence of adult asthma is around 6-7% in France. This disease is multifactorial and is related in particular to occupational factors. Using data from The French Health, Health Care and Insurance Survey (ESPS), this study aimed to describe asthma prevalence in France according to socio-economic status in 2012. METHODS: This analysis included the population aged 15 years and over. Current asthma, defined by a declaration of having asthma in the last 12 months, was analyzed according to socio-economic variables available in the ESPS survey. RESULTS: Among the 23,047 subjects interviewed, 12,565 were included in the analysis. Current asthma frequency was 7.4%. Higher risk of asthma was observed in unemployed, non-qualified persons, with a lower income, or having free healthcare insurance. Regarding occupations, in men, trade and commerce employees, personal services employees and administrative employees were associated with a higher level of current asthma prevalence. CONCLUSIONS: These results show that subjects with lower socio-economic status are more likely to suffer from asthma. New epidemiological tools in France, including cohorts (Constances, COSET) will be helpful to study more precisely the associations between asthma and occupational factors.

Biopersistence of nonfibrous mineral particles in the respiratory tracts of subjects following occupational exposure.

Transmission electron microscopy analysis (TEMA) was used to analyze the bronchoalveolar lavage fluid (BALF) of 262 subjects occupationally exposed (OE) to nonfibrous mineral particles (NFMP) and 42 controls not occupationally exposed to mineral dusts. OE subjects were divided into three groups according to the lapse of time since last exposure: < or = 1 year and < 10 years (E2), > or = 10 years (E3). The total BALF mineral particle concentration was significantly higher in OE patients than in controls and was closely related to the time lapse since last exposure to NFMP (median values for OE, 7.7 x 10(5) particles/ml; E1, 9 x 10(5) particles/ml; E2, 5 x 10(5) particles/ml; E3, 4.3 x 10(5) particles/ml; controls, 2 x 10(5) particles/ml). No statistical difference was observed for age and smoking habits between OE and control subjects. Concentrations of crystalline silica and metals (exogenous iron, aluminum, metallic alloys and other metals) were significantly higher in OE subjects than in controls, and even though these mineral concentrations decreased with increasing time since last occupational exposure, they still remained higher in the E3 group than in controls. Crystalline silica and metals were thus identified as biopersistent NFMP in the human lung using BALF ATEM method. This method is a useful tool in assessing occupational exposure to NFMP, even when a long period has elapsed since last exposure, and may be used in studying etiology of some respiratory diseases.

Predictors of life satisfaction amongst retired people in Paris.

BACKGROUND: The objective of the present study was to examine predictors of life satisfaction in a survey of retired men and women living in the Paris Metropolitan area. METHODS: In all 627 subjects took part in the first phase of the survey (1982-1983, T1), and 464 in the follow-up phase (1987-1988, T2) during which life satisfaction was evaluated, using the Life Satisfaction Index A (LSIA). Possible predictors were explored among the factors characterizing subjects at T1 and among those related to their occupational history. RESULTS: In the multivariate analyses, significant relationships were found between life satisfaction and the number of physical impairments and leisure activities, marital and mental health status and family relations. Taking into account the changes in these factors between the two phases of the survey increased the predictiveness of the regression models. CONCLUSIONS: These results confirm the links between life satisfaction and the factors generally recognized as its determinants. On the other hand, no effect of past occupational characteristics on life satisfaction long after retirement was shown.

Retrospective assessment of asbestos exposure--I. Case-control analysis in a study of lung cancer: efficiency of job-specific questionnaires and job exposure matrices.

Retrospective assessment of asbestos exposure--I. Case-control analysis in a study of lung cancer: efficiency of job-specific questionnaires and job exposure matrices. International Journal of Epidemiology 1993; 22 (Suppl. 2): S83-S95. In a lung cancer study in Northern Germany the asbestos exposure assessment obtained from detailed supplementary questionnaires (SQ) was compared to the assessment obtained by the application of two job exposure matrices (JEM) to the job history. The study includes 391 incident male cases and the same number of controls from the general population, matched by sex, age, and region. Almost 16% of the subjects are considered as never having been exposed to asbestos and 24% are classified as certainly exposed according to both of the JEM, the corresponding percentages of the SQ-method being 68% and 32%. Sixty percent are considered by the JEM as having an intermediate probability of exposure. In general, the agreement between the different methods is better when the exposure definition is restricted to definite exposures, the corresponding Kappa statistic being 0.67 for the comparison between both JEM and 0.44/0.39 between the JEM and the SQ. The positive agreement between SQ and JEM (reference) increases from 12% and 17% for subjects with low probability of exposure to 61% and 69% for those with definite exposures. A ranking according to cumulative exposure shows some dose-response relationship for each of the three methods with a smoking-adjusted OR in the highest category of 1.85 (95% CI: 1.01-3.38) for the SQ method and 2.47 (95% CI: 1.40-4.37) and 2.94 (95% CI: 1.73-4.99) for the two JEM. The results are discussed with reference to the conceptual differences between the methods and their potential scope in future studies.

Retrospective assessment of asbestos exposure--II. At the job level: complementarity of job-specific questionnaire and job exposure matrices.

Retrospective assessment of asbestos exposure--II. At the job level: Complementarity of job-specific questionnaire and job exposure matrices. International Journal of Epidemiology 1993; 22 (Suppl. 2): S96-S105. The assessments of asbestos exposure by two a priori job exposure matrices (JEM) and by a job-specific questionnaire (SQ) are compared at job level. The data used for the comparison were generated by an ongoing case-control study on lung cancer in a region of northern Germany with a relatively high past prevalence of asbestos exposure. Among job periods assessed as unexposed by either JEM, 96% are recognized as such by the SQ. Discrepancies between the SQ and JEM were observed in jobs rated potentially exposed by the JEM. Despite varying estimates, the JEM and SQ were consistent as regards the relative classification of job periods by probability of exposure. The concordance of the methods, estimated by Kappa statistics, was stronger for the two JEM than for either of the JEM and the SQ. The identification of specific occupation/industry combinations in which discrepancies were most frequent and the comparison with expert ratings in some jobs yield insights into the sources of the disagreement between the methods. The misclassification of exposure by the JEM usually results in an overestimation of exposure. This is essentially related to loss of information due to the use of job codes as surrogates for job task descriptions and to the insufficiency of published data on asbestos exposure in different industries. As regards the SQ, two main sources of potential loss of sensitivity were identified: 1) possible omission of indirect sources of exposure by this method, 2) possible incompleteness of the SQ. The present comparison of methods of asbestos exposure assessment does not allow any one approach to be considered superior to another. Indeed, as proposed by Ahrens et al. in Part I of the study, both should be used to ensure optimal epidemiological performance.

Physical diability after retirement and occupational risk factors during working life: a cross sectional epidemiological study in the Paris area.

STUDY OBJECTIVE: The aim was to examine the relationship between exposure to occupational risk factors during working life and physical disability after retirement. DESIGN: The study was a cross sectional epidemiological survey of a representative sample of retired subjects belonging to a supplementary pension fund in the Paris area. SETTING: The study took place in the general community. PATIENTS: 307 men and 320 women (63.1% of those approached) answered a questionnaire during home interviews. Their average age was 69 (SD4) years at the beginning of the survey. Whether or not subjects had been exposed to occupational risks was determined from their statements concerning the presence or absence of eight harmful environmental conditions while at work. Physical disability was defined as difficulty in carrying out seven basic activities of daily life. MAIN RESULTS: The results of univariate analyses showed significant relationships between exposure during working life to occupational risks including noise, heat, dust, carrying heavy loads, and awkward postures on the one hand, and the presence of a physical disability after retirement on the other. Multivariate analysis based on logistic regression models that took account of age, sex, and health impairments revealed a specific link between exposure to carrying heavy loads and physical disability after retirement. CONCLUSIONS: These results suggest that occupational risk factors might be important in determining such disability in retired people.

Reactive airways dysfunction syndrome caused by bromochlorodifluoromethane from fire extinguishers.

Although the neurological and cardiovascular effects of Freons have been extensively described, the respiratory effects have been less well documented. We report four cases of occupational asthma following accidental exposure to bromochlorodifluoromethane (Halon 1211) due to release of the contents of a fire extinguisher. All subjects developed an irritative reaction of the upper airways and lower respiratory symptoms immediately after exposure. Non-specific bronchial hyperreactivity was present for at least two months in all subjects and was still present more than two years after exposure in one case. The diagnosis of reactive airways dysfunction syndrome can be adopted in at least three of these four cases.

Healthy worker effect and changes in respiratory symptoms and lung function in hairdressing apprentices.

AIMS: To compare the prevalence and incidence of respiratory symptoms and lung function values between hairdressing apprentices and office apprentices. METHODS: A total of 322 hairdressing apprentices and 277 office apprentices (controls) were studied. Two cross sectional surveys were conducted in 1994 and 1996/97 with longitudinal follow up for a subgroup of apprentices (191 hairdressing apprentices and 189 office apprentices). RESULTS: In the initial phase, the prevalence of respiratory symptoms was significantly lower among hairdressing apprentices than among office apprentices. Lung function test results showed significantly higher values for hairdressing apprentices. Non-specific bronchial reactivity was similar in the two groups. In the final phase, results for respiratory symptoms were similar. The incidence of respiratory symptoms was not significantly different between hairdressing apprentices and office apprentices. Subjects who dropped out had lower values for FVC and FEV1 in the initial phase than those who completed the final phase. There was a significant deterioration of FEV1 and FEF25-75% in hairdressing apprentices compared to office apprentices. There was a link between atopy and the incidence of most of the respiratory symptoms (day/night cough, wheezing, dyspnoea, mucosal hyperresponsiveness) and between smoking and the incidence of bronchial hyperreactivity. There was no significant correlation between change in lung function tests and specific hairdressing activities reported at the end of the apprenticeship or with environmental working conditions in hairdressing salons. CONCLUSIONS: Although a healthy worker effect can be suspected, results showed a significant deterioration of baseline values of lung function tests in the hairdressing apprentice group. However, no clear link was shown between change in lung function tests and specific parameters of occupational activities.

[Development in health status of a group of retired subjects in the Paris region according to their practice of physical activity]. / Evolution de l'état de santé d'un groupe de retraités de la région parisienne selon la pratique d'une activité physique.

The relation between physical activity and health among retired people aged 65 and over was studied in a sample of 993 subjects, men and women, living at home in the Paris area and randomly selected from a pension fund roll. In 1982-1983 (T1), 627 subjects were interviewed. Five years later (T2), 464 subjects participated in the survey. Health was measured by the number and types of impairments and disability. The incidence of cardiorespiratory impairment and the incidence of disability were weaker among subjects with physical activity in T1 than among subjects without physical activity. These findings were unchanged after adjustment for age, sex, socioeconomic status, cigarette smoking, body mass index, uncomfortable housing, living alone and hard physical conditions during working life. This result suggests the beneficial effect of physical activity in promoting health among retired people aged 65 and over.

[Predictive factors of physical disability in a cohort of retired persons in Paris followed during 10 years]. / Facteurs prédictifs d'incapacité physique dans une cohorte de retraités parisiens suivis pendant dix ans.

OBJECTIVE: The objective of the present study was to examine predictors of physical disability in a survey of retired men and women living in the Paris area followed-up longitudinally for 10 years. METHODS: Subjects were randomly selected in a supplementary retirement pension fund. In all 627 subjects took part in the first phase of the survey (1982-83) and 392 in the follow-up phase (1992-93). At the 10-year follow-up, there were 185 confirmed deaths and 50 subjects refused to participate or could not be traced. Physical disability was measured by difficulties reported by the subjects for seven basic activities of daily life. Possible predictors, socio-demographic, impairments, physical activities, working conditions during working life were explored at T1. RESULTS: The incidence of physical disability was 41.4% for men and 57.6% for women. For disability in mobility, the incidence was 37.1% for men and 54.7% for women. In multivariate analysis, predictors of physical disability were social category (clerks), no physical activities, use of medicine, mental impairment. The predictors of disability in mobility were sex (women), social category (clerks), use of medicine, cardio-respiratory and sensory impairments. On the contrary, subjects with mental impairment had a lower incidence of disability in mobility than subjects without mental impairment. CONCLUSION: The results confirm the two poles of disability: biomedical and social. Working conditions during working life do not seem to play a direct part in incidence of disability at ten years follow-up.

[Longitudinal study of radiologic anomalies in subjects working in asbestos-insulated buildings]. / Etude longitudinale des anomalies radiologiques chez des sujets travaillant dans des locaux floqués à l'amiante.

The respiratory effects of environmental pollution by asbestos was examined in a cohort of subjects working inside university buildings partly insulated with asbestos containing materials (University of Jussieu in Paris). The present study concerned 727 subjects having undergone two standard radiographic examinations (postero-anterior and oblique chest x-ray) in the period 1981-1992. The first examination was realized between 01/01/81 and 31/12/85 and the second examination took place between 01/01/86 and 31/12/92. The subjects were classified into three groups according to their exposure status: the group G1 consisted of 161 workers occupationally exposed to asbestos; the group G2 comprised 416 subjects working for at least 15 yr in asbestos-insulated buildings without known occupational exposure to asbestos; the group G3 consisted of 150 workers working for at least 15 yr in the university with no known exposure to asbestos. Whatever the radiological abnormalities considered, no significant difference was observed between G2 and G3 in cross-sectional analyses of the two phases. The group G1 exhibited a significantly higher prevalence of pleural thickening compared to the other exposure groups after adjustment for confounding variables. Detailed examination of oblique x-ray allowed to confirm that pleural thickening were largely due to extrapleural fat. Concerning the changes in pleural abnormalities between the two phases of the study, no difference was observed between G2 and G3. This study was unable to show any excess of radiographic chest abnormalities among subjects working in asbestos-insulated buildings compared to non-exposed subjects. However, the participation in the second phase of examination was 51.2%. The study is still on-going. Therefore, it would be necessary to continue to follow-up the subjects because respiratory disorders could occur after a long latent period.

[Rolled atelectasis and asbestosis. Apropos of 26 patients]. / Atélectasie par enroulement et amiante. A propos de 26 patients.

Round atelectasis (AE) is a benign form of respiratory problem which develops due to fixing of the visceral pleura. This lesion for which the principal cause is exposure to asbestos may pose problems of differential diagnosis with bronchopulmonary cancer. In a cohort of 286 patients suffering from benign asbestos related pleural disease the diagnosis of round atelectasis was made on computerized tomography in 26 patients (31 AE) on the following criteria: rounded opacities of less than 7 cm in diameter situated at the periphery of the lung in contact with a thickened pleura with an acute angle linking the pleura and the opacity, a reduction of lung volume on the side of the atelectasis and the presence of a "comet tail sign". These patients were investigated to specify the circumstances of the occurrence, including their symptomatology, the changes in lung function, the topography of the round atelectasis and the associated radiological signs. Intense exposure to asbestos either continuous or discontinuous was found in 19 patients; 20 patients presented with some respiratory symptoms (dyspnoea 15/26, cough 11/26 and chest pain 9/26) but the reduction in lung function was moderate (7 had restrictive ventilatory trouble, 4 obstructive problems and a mixed problem in 1). The preferred localisation for round atelectasis was in the inferior lobes in the posterior basal lateral vertebral area (26/31) which may explain their being frequently missed on the standard radiograph (only one case of round atelectasis was visible on the straight chest radiograph in our study). An understanding of the pathology and the computered tomographic characteristics are now well defined and should enable an unnecessary diagnostic thoracotomy to be avoided which besides has no justification from the functional point of view.

Relation between job mobility during working life and health state after retirement: a cross sectional study of 627 subjects living in the Paris area.

The relation between job mobility during working life and health state after retirement was studied in a random sample of 627 retired men and women living in the Paris area who were beneficiaries of an interprofessional supplementary pension fund. State of health was evaluated by the number of health impairments that these subjects reported at the time of interview. Job mobility was defined by a dichotomic variable based on the number of different companies and branches of economic activity in which the subjects had worked. This information was obtained from the individual records supplied by the pension fund. For both sexes, a significant relation was found between the number of health impairments and job mobility: for men, the mean number of impairments was 1.7 in the high mobility group and 1.3 in the low mobility group, and for women these numbers were respectively 2.1 and 1.7. This finding seemed independent of the effects of selection and of the effects of factors such as age at the time of interview, age at retirement, previous diseases, past work accidents, and previous occupational exposures. These results suggest that a high job mobility during working life might be a risk factor for health after retirement.

Evolution of osteoarticular disorders as a function of past heavy physical work factors: longitudinal analysis of 627 retired subjects living in the Paris area.

The relations between osteoarticular disorders and occupational exposure to heavy physical work factors were studied in a random sample of retired subjects living in the Paris area, all of whom had contributed to the same retirement pension fund. 627 subjects were originally seen in 1982-3 and 464 of them were seen again five years later. On both occasions, the same questionnaire was completed during a home interview. Osteoarticular disorders were evaluated by the presence of pain, with or without restricted joint movement, for at least six months before interview. The heavy physical work factors were those reported by the subject at the first interview, and only subjects who stated that they had been exposed to these factors for more than 10 years were considered as exposed persons. For those who were seen twice, the frequency of osteoarticular pain increased during the five years between the two interviews, from 52% to 65% in the men and 72% to 82% in the women. Among both sexes, these frequencies were significantly higher in those who stated that in the past they had to carry heavy weights and work in tiring positions. The increases in frequency of pain during the five year study period were also related to these occupational factors. In general, the frequencies for subjects not exposed to occupational factors caught up with those found for the exposed group. This interaction of age with the relation between exposure to heavy physical work factors and osteoarticular disorders does not seem to be explained by confounding factors, including age at the first interview, the fact of living alone, of being a former manual worker, of having a cardiorespiratory disorder, and smoking habits. The results of the survey suggest that working conditions are an important cause of osteoarticular disorders that last well beyond the end of working life.

Pleural plaques, asbestos exposure, and asbestos bodies in bronchoalveolar lavage fluid.

The profiles of occupational asbestos exposure were investigated in a series of 66 hospital patients in whom pleural plaques constituted the only asbestos-induced abnormality. The relationship between a radiological semiquantitative score of pleural plaques and indices of asbestos exposure was also examined. On the basis of a standardized occupational questionnaire, four classes of asbestos exposure were distinguished in our study population: no evidence of exposure, low-level exposure, sporadic exposure at higher levels, and a remaining group of individuals with substantial exposure. Asbestos body count in bronchoalveolar lavage fluid (BALF) was used as an objective indicator of cumulative lung retention of asbestos. Our results support the data indicating that pleural plaques may occur in subjects with low-level or sporadic asbestos exposure. Although it is admitted that pleural plaques are strongly associated with past asbestos exposure, our data suggest that the stage of pleural plaques was not correlated to the level, frequency, duration of exposure nor to the amount of asbestos bodies in the BALF in subjects free of any lung parenchymal abnormalities on high resolution computerized tomography.

Measurement of bronchial responsiveness by forced oscillation technique in occupational epidemiology.

The performance of the forced oscillation technique (FOT) in the assessment of bronchial responsiveness on the methacholine challenge test was compared with that of forced expiratory volume in one second (FEV1) in 119 active workers with normal baseline pulmonary function. Changes in resistance (delta R0%), frequency dependence of resistance (delta P) and resonant frequency (delta F%) determined by the FOT were compared to the delta FEV1%. Receiver operating characteristic (ROC) curves were established to determine values of the changes in FOT parameters which corresponded to the best sensitivity and specificity for classifying the subjects as hyperresponsive or nonresponsive on the methacholine challenge test. Significant correlations were observed between delta FEV1% and delta R0%, delta P and delta F% respectively. The ROC curves showed the following cut-off values of FOT parameters to be the best values for classifying the subjects according to the presence or absence of 20% fall in FEV1: a 65% increase in R0 (sensitivity 75%; specificity: 76%); a decrease of 65 x 10(-3) hPa.l-1.s2 in P (sensitivity 58%; specificity 83%); a 50% increase in F (sensitivity 75%; specificity 62%). Our results suggest that the FOT is a useful test for assessment of bronchial hyperresponsiveness when compared to spirometry, and can be applied to epidemiological studies of a bronchial challenge test in normal active working populations.

Retention of asbestos bodies in the lungs of welders.

Examination of asbestos bodies (AB) retained in the lungs is a useful way of assessing past occupational exposure to this material. AB retention has been extensively studied in workers directly exposed to asbestos, but less so in those end users, such as welders, who use asbestos-containing products. We therefore retrospectively studied AB retention in 211 welders, for whom biological testing procedures had been requested by a chest physician, between 1988 and 1991. Optical microscopy of AB was performed on samples of sputum (40 subjects), bronchoalveolar lavage fluid (BAL) (147 subjects), and lung tissue obtained after thoracotomy (38 subjects). Information on previous jobs and exposure was obtained using a questionnaire (the mean duration of welding activities was 16.6 years). Eighty-two subjects (38.9%) had elevated lung retention of AB in all the samples studied. Significant AB retention occurred in only 30% of sputum samples, but in 40.1% of BAL samples and 39.5% of lung tissue samples. The duration of welding activities correlated with the density of AB in BAL or lung tissue (r = 0.31, p < 0.01 and r = 0.49, p < 0.05, respectively). On the basis of the questionnaire, only two of the welders with significant AB retention had other occupational exposure to asbestos. Our findings suggest that welding activities may increase lung retention of AB, and consequently might produce higher risks of fibrotic and/or malignant pulmonary diseases. These potential risks need to be brought to the attention of doctors; a longitudinal follow-up may also be warranted in such populations, even after individuals have ceased their welding jobs.

Pleural mesothelioma: a descriptive analysis based on a case-control study and mortality data in Ile de France, 1987-1990.

Incidence rates of pleural mesothelioma in Ile de France were examined for the period 1987-1990, on the basis of information collected in a case-control study. This study was designed to include all new cases of pleural mesothelioma occurring in the region. On the other hand, mortality rates from pleural malignancies in the same region were examined on the basis of death certificates recorded by INSERM for the same period. A large difference was found between the two types of data. Average annual incidence rates were 7.5 per million among men and 1.6 per million among women. Average annual mortality rates due to primary pleural malignancies were 25.2 per million in males and 8.9 per million in females. This study confirms discordances between incidence and mortality data for pleural malignancies already reported in several countries. However, contrasting with some previous reports, the annual mortality rate from pleural malignancies was higher than the incidence rate of mesothelioma in this study. This emphasizes the usefulness of a specific investigation to explain such discordances, prior to comparison of data from one country to another.

A cross-sectional study of the health effects of work schedules on 3212 hospital workers in France: implications for the new French work schedules policy.

This study was designed to investigate the effects of work schedules on the health of hospital workers at the Assistance Publique-Hôpitaux de Paris (AP-HP). Out of 40 hospitals, 17 volunteered to participate in this study. The Standard Shiftwork Index and a questionnaire concerning physicians' work schedules were used. Ten thousand questionnaires were distributed anonymously to hospital workers between March and April 1999. Professional categories comprised head nurses, nurses, nursing auxiliaries, hospital agents, midwives and full time physicians. Departments included internal and geriatric medicine, general paediatrics, orthopaedic and general surgery, operating and emergency rooms, and anaesthesiology and intensive care units. 3250 questionnaires were returned. Demographics for the respondents were: 79.2% female, average age 38.1 +/- 9.1 years old. Eleven work schedules were identified. One fourth of the personnel had fixed morning work schedules. The highest level of job satisfaction was found in personnel working in paediatrics while dissatisfaction was strongest in the gerontology and, emergency room personnel. General Health Questionnaire (GHQ) scores were high for head nurses, operating room nurses and junior doctors as well as for personnel with rotating and flexible shifts. This study will be used to make recommendations concerning the reduction of working time for French hospital workers.