[Epidemiological factors of lumbar disk herniation].

Two series of patients operated on for an herniated lumbar disc are studied retrospectively for the 484 cases of the first one and prospectively for the 289 cases of the second series. In both series, the large majority of the cases are aged between 30 and 60 years, about 60% are males and the body mass index (B.M.I.) is equally distributed among the patients and in the general swiss population of the same age. Only young men are heavier than the average. All the professions are represented among the patients, as the inactives or housewives, and not very different than in the normal population. Only in the first series heavy workers are considered as more frequent among the patients than in the population of Geneva. This is not confirmed by the second series. Sport is a possible factor implicated in the disease. It is suggested that heavy work or intensive sport in the adolescence can influence this problem. The incidence of herniated disc syndrome calculated from the second series in Geneva for people aged 20 to 69 is 62 cases/100,000/y, 75 for male and 51 for female. This is under the reality because some cases are operated in private clinics.