So far, eight prospective studies and 50 cross-sectional or retrospective studies have focused on risk factors for low back syndromes. Half of these have been published during the 1980s. Hard physical work and, in particular, frequent lifting and postural stress are likely to result in disc degeneration, low back pain and sciatica. Physical strain may also have prophylactic effects, as physical leisure activity and muscular strength are negatively associated with the risk of low back pain. Much evidence points to driving motor vehicles being causally associated with low back pain and sciatica. A probably causal relationship exists between body height and risk of sciatica, but height is not necessarily predictive of other types of low back pain. Obesity, smoking, psychological distress and poor general health also carry increased risk of low back pain, but their causal role is questionable. Although none of the suspected risk factors can be described as having been conclusively investigated epidemiologically, the results of published studies show that there are modifiable factors contributing to low back pain. The overall potential of primary prevention is great if adequate tools for intervention can be developed.