A prospective study of low back pain in a general population. I. Occurrence, recurrence and aetiology.

A general population of 928 men and women aged 30, 40, 50, and 60 years underwent a lower back examination as part of a general health survey. A 12 month follow-up questionnaire was completed by 99% of them. At the end of the follow-up year, the life time prevalence rates for low back pain (LBP) were 68-70% for men and rose with increasing age from 62% to 81% among women. The one year incidence of first attacks of LBP was 11% among the 30-year-olds and decreased in the older age-groups. Recurrences of LBP in the follow-up year were more frequent among those who had more recently and frequently experienced LBP before. Among those who had experienced LBP on some occasion, 23-31% had such symptoms daily or at least once a week. Heavy lifting, twisting and trauma were the most commonly stated causes of LBP, which 52-60% of the participants claimed to be work-related. A gradual onset and exacerbation of the LBP were of some prognostic value in the follow-up year, while the alleged cause of previous LBP was not.