In a population-based multi-centre case-control study (German Spine Study EPILIFT) on 915 cases with discrelated diseases in the lumbar spine and 901 control subjects, the dose-response relationship was investigated between occupational spine loading caused by manual materials handling and trunk flexion, on the one hand, and lumbar spine diseases, on the other hand. The 915 cases can be characterized by the following groups: 286 male (case group 1) and 278 female patients (case group 1) with outpatient or inpatient treatment in a hospital because of lumbar disc herniation with sensitive and/or motor radix syndrom as well as 145 male patients (group 3) and 206 female patients (group 4) with inpatient or outpatient treatment in a hospital or outpatient treatment in an orthopaedic practice due to severe osteochondrosis combined with reduction of the disc height and the verification of a sensitive and/or motor radix syndrome or a local lumbar syndrome (the latter with a finger-bottom-distance of at least 25 cm). In the regions of Frankfurt am Main, Freiburg, Halle and Regensburg, the case subjects were recruited in hospitals or orthopaedic practices and were included in the study if the persons had their main residence in defined surrounding regions of the respective cities. The control subjects represent a random sample of the resident population in the same regions. Case and control subjects should be aged between 25 to 70 years at the date of recruitment. For the case subjects, the diagnosis was verified with a second radiological and clinical assessment. The response rate was 66.4% among the case subjects and 53.4% among the control subjects. The analysis of the nonresponders showed that in both cases and controls, the whitecollar workers had a higher response rate than the blue-collar workers. Consequently, there was no evidence for a differential bias in cases and controls with reference to the social status. At both cases and controls a standardized individual interview lasting about one and a half hour was conducted by trained interviewers concerning occupational spine-related exposure. Furthermore, information was gathered about, amongst others, exposure to hobby and sports as well as body height, weight and former diseases of the spine. At those subjects who exceeded defined occupational "exposure thresholds", a semi-standardised comprehensive expert interview of about two hours was performed by the technical inspectors of the institutions for statutory accident insurance and prevention ("TechnischerAufsichtsdienst", "TAD"). In this interview, information was obtained to occupational activities with relevant spine-related exposure induced by manual materials handling, trunk inclination and twisting or by whole-body vibration. The results of the TAD interview to external loading factors were biomechanically analysed. As characteristic values of spinal load, the compressive force on the lumbosacral disc was calculated for each loading activity and cumulated for working shifts and the occupational life applying, in total, ten cumulative dose models - the "Mainz-Dortmund dose model" included - with partially reduced thresholds for trunk inclination and disc-compression at materials handling, with consideration of other types of handling modes like pulling and pushing, besides lifting and carrying, as wells as with several weightings of the lumbar compression in relation to activity duration (linear, squared, cubic or tetra-powered). This methodology of 10 dose models was chosen in order to identify the mathematically optimum relationship between exposure and disease risk.