Interaction of height and mechanical loading of the spine in the development of low-back pain.

The relation of low-back pain to height and physical activity was examined among 2667 British men and women aged 20-59 years and selected from the general population. Information about occupational activities, height, and lifetime history of low-back pain was obtained from a postal questionnaire. The lifetime prevalence of low-back pain was 58.3%. After allowance for other occupational activities, the onset of low-back pain was strongly associated with heavy lifting at work (men: relative risk (RR) 2.0, 95% confidence interval (95% CI) 1.4-2.8; women: RR 2.2, 95% CI 1.3-3.5). For the men there was also an association with digging (RR 1.6, 95% CI 1.1-2.3). Risk of low-back pain increased with height among the men but not among the women. The risks associated with heavy lifting and digging were greater for the short than for the tall men. Thus the data provide no justification for excluding tall men from heavy manual tasks, despite their greater susceptibility to back problems.