RESUMEN
OBJECTIVE: In Korea, there appears to be an increase in the diagnosis of lumbar spine disorders recently. This trend has urged employers to screen new employees for this disorder. One of the methods for the investigation is the radiological examination of the lumbar spine. We studied the prevalence of spondylolysis according to age and sex with lumbar X-ray (anterior-posterior view and lateral view) of new employees in pre-employment screening examination. We also estimated the outbreak period of spondylolysis by analysing the prevalence rates at each age group, which were the results of our study. METHODS: We gathered the data of lumbar X-ray findings for new employees, who had recieved pre-employment screening examinations in the department of occupational and environmental medicine of Masan Samsung Hospital Korea during a period from January 1, 2002 to December 31, 2005. We analyzed the data to obtain the age and sex prevalence of spondylolysis and spina bifida. RESULTS: The prevalence of spondylolysis for the pre-employment screening examination was 5.9% (male 6.6%; female 4.3%) in this study. The prevalence of spondylolysis after adjusting age and sex was 9.0%. The prevalence of spondylolysis was positively correlated with age, and showed to be higher in female than male. Body mass index of spondylolytic subjects was higher than that of normal. The prevalence of spondylolysis was significantly higher in those with spina bifida than normal subjects. CONCLUSION: The prevalence of spondylolysis of the pre-employment screening examination was 5.9% in this study. The factors which relates with spondylolysis were age, BMI and the prevalence of spina bifida.