Cervical spine degenerative changes (narrowed intervertebral disc spaces and osteophytes) in coal miners

A series of 685 x-ray films of the cervical spine obtained in coal miners was analyzed to explore the occurrence of narrowed disc spaces and osteophytes in this occupational group, and to examine the association of x-ray changes with age, duration of employment, and duration of occupational exposure to hand-arm vibration. All data were extracted from individual medical files of coal miners examined for suspected hand-arm vibration-related disorders in 1989-1999 at the Occupational Medicine Center in Katowice. The narrowed intervertebral disc spaces were found in 188 coal miners (26.9%) and osteophytes in 332 coal miners (47.5%). The occurrence of degenerative changes in coal miners was similar to that observed in a small group of 68 blue-collar workers (no exposure to hand-arm vibration) employed in the coal industry. Univariate comparisons showed that narrowed intervertebral disc spaces and osteophytes were more frequent among older subjects and among subjects with longer duration of employment. The prevalence of changes also showed some relationship with the number of years of exposure to hand-arm vibration. The results of logistic regression analysis confirmed statistically significant effect of age, but not of other factors included in the model. When both x-ray changes were grouped together (a combined dependent variable) age remained the only statistically significant explanatory variable. The findings do not support the view that the examined degenerative changes in the cervical spine are more prevalent in coal miners and depend on duration of physical work or local exposure to hand-arm vibration in this occupational group.