Early risk factors for lumbar discectomy: an 11-year follow-up of 57,408 adolescents.

There is a lack of longitudinal studies on the risk factors of lumbar discectomy. Using combined population survey and hospital discharge register data in a prospective longitudinal design, we investigated the association between adolescent risk factors and lumbar discectomy until early middle age. A prospective cohort of health survey respondents (n = 57,408) aged 14-18 years was followed for 651,000 person-years (average follow-up, 11.3 years). Study endpoints were lumbar discectomy, death or end of follow-up. Participants' mean age at the end of follow-up was 27 years. In multivariate Cox's regression analysis, the significant risk factor for lumbar discectomy among male respondents was daily smoking, HR being 1.5 (95% CI 1.1-2.2). In females, frequent participation in sports clubs (HR 2.7, 95% CI 1.1-6.3) and overweight (HR 2.1; 95% CI 1.1-4.1) were significantly associated with an increased risk of lumbar discectomy. Daily smoking in males and frequent participation in sports clubs and overweight in females measured at adolescence were statistically associated with lumbar discectomy at an 11-year follow-up, although the hazard ratios were relatively small. Further study of these common risk factors and their modifications may lead to a better understanding of the causes of lumbar disc herniation.