In this national internet survey, we found that more than 64% of full-time working women living with FM had taken sick leave during the preceding year, for a total of 37 days on average. Demographic and clinical characteristics were not associated with the risk of sick leave, whereas occupational characteristics were: commute time, difficulties at work, problems with career progression, sedentary position with repetitive gestures and a lack of recognition of FM by colleagues and bosses. These findings are important for the management of FM in the workplace, because most of the risk factors are related to the workplace and can be modified, preferably with the help of an occupational physician aware of the problems to be resolved.
Sick leave in women with FM
More than two thirds of the professionally active women living with FM included in this study had taken sick leave during the preceding year. This finding is consistent with previous studies, not necessarily restricted to women. In a retrospective Spanish study of 301 FM patients conducted in 2007, 67.8% of the workers questioned had been on sick leave during the year, and the mean number of days off work was estimated at 44 ± 69.6 days . In the United States, according to data for 2009 from the Medical Disability Advisor, the mean duration of sick leave for fibromyalgia syndrome was estimated at 65 days per year . Employees with FM have been found to take three times as much sick leave as other workers without this disease: mean of 29.8 ± 70.6 days of sick leave for subjects with FM, versus 10.4 ± 33.6 days for the total population and 25.7 ± 62.4 days for subjects with osteoarthritis . FM sufferers reported limitations in the performance of their jobs [12, 13, 15], with a significant number of absences for medical reasons [10, 23]. Women who took sick leave were more likely to be prescribed antidepressants than those who did not. The use of antidepressants was clearly declared in the questionnaire by the patients. An explanation could be that’s this prescription was necessary when being at work, and less when being in sick leave. Moreover, women at work or declaring less than 30 days of sick leave, reported better support from their partner. To our knowledge, no data has been published on these 2 observations.
Impact of FM on the capacity to work, and the role of the occupational physician
Most of the women in our study reported limitations on their capacity to work, with a significant impact on their professional career, difficulties and stress at work. Women with FM often report being less flexible at work, with limitations of their movements and work positions, and difficulties adapting to new and changing work tasks . In a European study published in 2010 (n = 299), 74% of employees with FM reported being less productive at work . Physical and mental overload at work can influence the mental and physical symptoms of FM , limit the chances of holding down a job  and increase stress at work. In a study by Teasell and Merskey, work disability was found to be correlated with the demands of physical work rather than symptom severity .
Most of the women had not consulted their occupational physician, but little is known about the role of occupational physicians in helping patients with FM in the workplace. The women who had not been on sick leave in the preceding year were more likely to report a lack of support from coworkers and their occupational physicians than the other women. A lack of understanding and support from coworkers and employers was identified as a factor influencing the ability of subjects with chronic musculoskeletal pain to hold down jobs . A supportive work climate including understanding from colleagues and bosses is important for job satisfaction .
Job characteristics and the risk of sick leave in women with FM
We found that women performing repetitive actions in a sedentary position were more likely to take sick leave. In the Spanish study by Rivera et al. (n = 301), sedentary jobs (unspecified) were found to be associated with sick leave (OR: 3.93, 95% CI 1.69–9.13, p = 0.001) . In a qualitative Swedish study on FM and employment, the ability of the study subjects to remain in work was found to be related not only to individual work capacity, but also to the work environment and domestic work requirements . Our study showed that difficulties in career progression and getting colleagues and bosses to recognize the disease are associated with sick leave. A japanese study on 15,531 workers followed during 5 years reported reasons for sick leave duration of more than 30 consecutive days . The results showed that workers having support from their employers and colleagues had less days of sick leave. Our study showed also that sedentary professional activity with repeated movements and exposure to a noisy working environment were related to sick leave. The following independent risk factors for sick leave (commute time, difficulties at work, fibromyalgia hindering career progression, sedentary professional activity with repeated movements, difficulty getting colleagues and bosses to recognize the disease) were clinically meaningful. Commute time to get to work and difficulties at work were observed as independent risk factors at the beginning of days of sick leave. Moreover, odds ratio increased with the number of days of sick leave for all the risk factors and were more important after 30 days of sick leave. For example, odds ratio were over 2 in participants having more than 61 days of sick leave.
Other authors reported that job type, uncomfortable working positions with the carrying of heavy loads, repetitive movements, and prolonged sitting or standing have been identified as factors limiting the ability of people with chronic musculoskeletal disorders to hold down a job [27, 29]. In 2005, Henriksson et al. advocated avoiding certain work situations with a heavy physical load, frequent carrying, static or repetitive movements, or movements over the shoulder plane, to improve the ability of women with FM to hold down jobs . In a study by Teasell and Merskey, work disability was found to be correlated with the demands of physical work rather than the severity of FM symptoms .
Most of the women in our study had not had any adaptation of their working conditions. The adjustment of work tasks and of the working environment seems to be the main factor influencing the ability of workers with FM to remain in employment [5, 13]. However, it may be difficult to make the necessary adjustments in today’s working world .
We found that the duration of sick leave taken by working women with FM increased proportionally with commute time. The journey between home and work should always be taken into account when assessing working capacity, according to Liedberg et al. . These authors pointed out that the ability of individuals to remain in work is dependent not only on their symptoms, but also on the adaptation of the working environment and work tasks on a case-by-case basis .
The clinical and demographic characteristics of FM patients have only a minor effect in the workplace
Our results indicate that demographic and clinical characteristics of FM patients are not risk factors for sick leave. Similarly, Salido et al., in a small study of 51 Spanish women with FM, found no significant relationship between sick leave and sociodemographic characteristics . Indeed, the demographic and clinical characteristics of the women participating in this study were similar to those reported in previous epidemiological surveys [32,33,34,35].
Almost all the women in our study complained of pain and fatigue, with more than 90% reporting sleep disorders and over two thirds having cognitive impairment. FM severity, based on FIQ score, was similar in the different groups. In a US cross-sectional study of 2596 people with FM , the most commonly reported clinical symptoms were similar to those reported here, including morning stiffness, fatigue, non-restorative sleep, pain and cognitive disorders. The subjects in employment felt that their symptoms compromised their ability to be productive, due to repeated absences and shorter working times .
Contrary to our findings, Rivera et al. found, in 2007, that women who stopped work during the year had more clinical manifestations of FM, more associated comorbidities, a worse quality of life and poorer functioning, with a significantly higher total QIF than women who remained professionally active . The number of clinical symptoms (OR = 1.41, 95% CI 1.10–1.82, 0.006) and fatigue (OR 1.07, 95% CI 1.00–1.14, p = 0.025) were independently associated with sick leave in this previous study .
In our study, women who had not taken sick leave in the previous year were more likely than the others to report a lack of support from their spouse. Liedberg also stressed the vital role of the family circle in keeping people with FM in work, with women stressing the importance of family support to cope with the emotional reactions caused by fatigue and irritation after a day’s work .
Limitations of our study
One of the limitations of this study was the mode of inclusion of the study population, based on self-selection. In addition, only patients with access to the website of the patient organization were able to participate in the study . We did not assess the reason for the sick leave. Moreover, the diagnosis of FM was based on self-evaluation by the women included in the study, and all data were declarative. However, the sociodemographic and professional information for our sample was comparable to that in other published studies.
The cross-sectional analyses presented here only identify associations; they do not establish a causal link. Some key work-related data were missing, as an incident during the online posting of the questionnaire prevented us from obtaining access to some of the data relating to employment.
Moreover many comparisons were performed, resulting in increasing type I error.