BMC Public Health 2008, 8:159 http://www.biomedcentral.com/1471-2458/8/159 Background The importance for the health situation of having secure employment has been increasingly emphasised in new public health policies, and having a job, in contrast to being unemployed, is regarded as an important determi- nant of health [1,2]. A possible explanation, based mainly on research and theories about the negative health conse- quences of unemployment, is that transition from unem- ployment to a paid job improves health. The first meta-analysis about the possible health effects of reemployment was published recently and showed improvement in mental health when unemployed per- sons were reemployed [3]. Other research has suggested that the positive effects of reemployment after unemploy- ment may be limited to those who gain satisfactory new jobs [3-5]. A recent German study on health satisfaction found that even though there is a negative health effect of long-term unemployment on both men and women, reemployment has a positive effect on health satisfaction independently of the duration of the period of unemploy- ment for both men and women [6]. Overall, research in the field is scarce. There is more abundant research on, and agreement about, the relation between unemployment on the one hand and poor well-being and poor psychological and physical health on the other [3,6-11]. The longer the time in unemployment [3,6] and the younger the ages [3,12], the worse are the consequences to health. Different theo- retical models have been used to explain the association between unemployment and health and these models can be indirectly used to explain the possible health-promot- ing effects of reemployment after being unemployed. The economic deprivation model assumes that unemployment leads to poverty and other forms of disadvantage, which we know are associated with poor health. Research has also shown a negative relationship between perceived financial strain and well-being during unemployment [13,14]. According to the theory of latent function, there are also non-financial benefits provided by a job, such as opportunities for social contacts and improved status (for example, that people do not look down on you) [15]. On the other hand, the health situation of the unem- ployed may not be improved by reemployment. A previ- ously long-term unemployed person who is reemployed may continue to have the self-image and identity of an unemployed person (e.g. feeling that people look down on you) [16]. Moreover, insecure employment with a potential risk of unemployment could be health-impair- ing [17,18]. It was found that those who are permanently employed in non-preferred occupations and undesired workplaces reported more symptoms of ill-health than a comparative group [19]. Also, those who were not in pre- ferred occupations continued to cope with job loss simi- larly to those who were unemployed [20]. Different models have been suggested for how a stressor may affect health over time. The model of accumulation of strain implies that strain does not go away when the stres- sor disappears [21]. According to the Karasek-Theorell's demand-control model, unemployment can be regarded as a passive situation, with negative health consequences related to a combination of low control and low demands [22]. The strain of being unemployed may persist when reemployed. Moreover, obtaining a job can be a new stressor that adds additional strain to the strain accumulated during unem- ployment. The combination of employment and family demands (such as having dependent children) could make reemployment after unemployment more stressful, especially for mothers who usually have the main respon- sibility for domestic work [23,24]. The value of having a job, commonly measured by the Work Involvement Scale [25], may also have an impact on well-being in the transi- tion from unemployment to work [9,26]. Long-term unemployment may lead to decreased value in having a job [27-29] which can influence the reemployment proc- ess negatively. Among demographic variables, gender was found to have interesting patterns, e.g. that it might be more difficult for women with good health to enter paid employment than men with a similar health situation [30]. Simultaneously as a meta-analysis concludes that unemployment is psy- chologically more damaging for women [3], it has also been found that transition from unemployment to a paid job was only associated with improved psychological well-being among women [31]. Therefore, more research is needed about the importance of gender in the transition from unemployment and other kinds of unstable labour market positions to employment. To summarize, the question of whether transition from an unstable labour market position to permanent employ- ment protects mental health remains to be studied. There are several methodological inadequacies in previ- ous research on the health consequences of reemploy- ment. First, possible confounders in the relationship between reemployment and health need to be taken more into account. Having employed rather than unemployed relatives, especially in younger ages, might increase the possibilities of finding a job. Socio-economic status may also act as a confounder between health status and reem- ployment. There is overwhelming documentation of the relation between a working-class position and poor health status [32]. Also, socioeconomic status can influence Page 2 of 11 (page number not for citation purposes)