Occupational health
to reduce work-related disease
Hazardous working conditions may have a profound impact on health of workers. At the same time, workers are partly selected by their good health. Thus, our research addresses both the effect of work on health and the effect of health on work participation.
With respect to the effects of work on health we focus on musculoskeletal disorders, reproductive disorders, and cancer (mesothelioma). Our studies consist of detailed assessment of exposure to risk factors at the workplace, evaluation of exposure-response relationships and an estimate of the proportion of disease that can be attributed to a particular exposure at the workplace. Interventions may include reducing exposure to risk factors at the workplace, administrative procedures and policies, personal advice concerning worker behaviour and training, and medical interventions aimed at improving prognosis of disorders and facilitating early return to work.
The studies on the effects of health on work address primarily the selection mechanisms causing people to be able to work or not. In longitudinal studies the effects of (determinants of) health complaints and diseases, such as early arthritis, on ability to work and withdrawal from the labour force through disability, early retirement, and unemployment are investigated. Other studies focus on the role of health among unemployed persons in gaining access to labour force participation again.
Public Health Impact
The societal impact of our research team was most obvious for asbestos. Under commission of the Ministry of Environment we demonstrated that asbestos waste used as covering material on yards and dirt roads was the most likely cause of an additional 2 cases of pleural mesothelioma per year in a region with 150,000 inhabitants. The results were presented at a press conference, and subsequently reported as headline news in 10 national newspapers and via interviews on television and radio. The study was also subject of a parliamentary debate and explicitly used by the Ministry of Environment to announce within 24 hours their new policy on the removal of asbestos from the environment.
A second activity was also related to the continuing asbestos saga. With the financial support of the Ministry of Social Affairs and Employment we contributed to the development of a national database on historical exposure to asbestos at the workplace. This database is in use at the Institute for Asbestos Victims, an independent foundation that mediates for compensation to workers with mesothelioma. The database is public domain and can be accessed at www.asbestkaart.nl.
Research Highlight: Occupational Risk Factors for Cryptorchidism and Hypospadias in Newborn Boys
(Pierik et al., Environ Health Perspec, 2004)
In the past two decades concern has been raised over a possible increase in disorders of the male reproductive tract, including cryptorchidism (undescended or maldescended testis), hypospadias (birth defect with urinary tract opening at ventral side of the penis), as well as testicular cancer and impaired semen quality. It has been suggested that these disorders are caused by exposure to endocrine disruptive agents.
In the Rotterdam area we conducted a nested case-control study. Within a cohort of 8,698 male births, 78 cryptorchidism cases and 56 hypospadias cases were compared with 313 controls. The participation rate was 85% for cases and 68% for controls. Detailed interviews were conducted with both parents at home on pregnancy aspects and personal characteristics, lifestyle, occupation, and dietary phyto-oestrogen intake. We found that paternal pesticide exposure was associated with an increased risk of cryptorchidism. Paternal self-reported exposure to organic solvents was weakly associated with hypospadias. Smoking of the father was a strong risk factor for hypospadias. Maternal occupational, dietary, and lifestyle exposures were not associated with either abnormality.
These findings strongly suggest that occupational exposure to specific chemicals of the father is a risk factor for cryptorchidism and hypospadias in the offspring. The observed effects are difficult to explain through an endocrine disruption mechanism. We recommend that future studies on reproductive disorders should not only focus on maternal exposure before or during pregnancy, but also include the paternal pathway.