[Back problems during military service--significance for later back problems. A 12-year follow-up study].

One thousand and fifty-eight conscripts participating in an investigation of back problems among conscripts in 1979-80 were re-examined 12 years later with an identical questionnaire concerning back problems. The questionnaire was answered by seven hundred and eighty-four persons (74%). The lifetime prevalence for low-back trouble was 73%, the one-year prevalence 53% and the point prevalence 26%. At the time of follow-up the incidence of low-back trouble depended on ever having had back pains and on having an X-ray made because of back problems. The probability for sick leave from work caused by lowback trouble was increased when back troubles had been reported at the time of the initial investigation. A significant amount of the conscripts that had been rejected due to back problems (60%) had been unfit for work because of low-back trouble in the follow-up period, and 95% of them had had low-back trouble in the year before follow-up, compared to 51% of the other conscripts. Previous back trouble increases the risk of getting back trouble once again. The risk of sick leave from work caused by low-back trouble increases with the incidence of back trouble up to the investigation in 1979-80. Rejection from service due to back problems increases the risk of later low-back trouble and sick leave from work caused by low-back troubles.