The Social Court in the State of Lower Saxony (LSG) reached a verdict on February 5, 1998 in which it states the view that any adoption into the list of occupational diseases as documented in section 551 section 1 sentence 3 RVO, with the requirement of a considerably higher risk in certain groups of people, mandates the proof of a more than twofold risk of developing the disease in the exposed occupational group in comparison to the rest of the population; this requirement could not be fulfilled in diseases of the lumbar spine (occupational disease No. 2108 BKV) resulting from disorders of the intervertebral disks due to its rate of incidence in the general population. The goal of this study is to clarify the relationship between the relative risk, the prevalence-odds ratio and the prevalence ratio using the example of a hypothetical cohort. The results show that a high disease prevalence in the non-exposed population does not principally exclude a relative risk of 2. Generally cross-sectional studies have to be interpreted with caution in regard to the size of the relative risk due to the fact that only the prevalence-odds ratios and the prevalence ratios can be used for calculation purposes. The 'healthy worker effect', which is particularly prevalent in cross-sectional studies performed within a company and difficult to assess in regard to its magnitude, has a tendency to result in an underestimation of the relative risk. Therefore, only a correct examination of all epidemiological study results pertaining to a specific disease using a critical method of analysis can give the required information as to if and at which level of exposure the criterium 'risk doubling' is actually fulfilled.