There are few published studies on the relationship between occupational lumbar load and facet joint degeneration (FJD). This cross-sectional study was conducted to evaluate the effect of physical lumbar load on FJD by comparing magnetic resonance imaging (MRI) findings of firefighters (FFs) and hospital office workers (HOWs).

We randomly sampled 341 male FFs and 80 male HOWs by age stratification. A questionnaire and clinical examination, including MRI of the lumbar spine (T12-S1), were conducted. FJD was diagnosed and graded by using the classification of Pathria et al., and reclassified into two groups as follows: no FJD (grade 0) and FJD (grades 1, 2, and 3). The prevalence of FJD was analyzed according to occupational group.

The prevalence of FJD ranged from 31% (L1–L2) to 75% (L4–L5) in the FFs, and from 18% (L1–L2) to 69% (L4–L5) in the HOWs. After adjustment for age, body mass index, and frequency of physical exercise, the adjusted odds ratios (OR) for FJD in the FFs were significantly higher than those in the HOWs at all lumbar spinal levels, except for L3–L4 (L1–L2: OR, 2.644; 95% confidence interval [CI], 1.317–5.310; L2–L3: OR, 2.285; 95% CI, 1.304–4.006; L4–L5: OR, 1.918; 95% CI, 1.037–3.544; L5–S1: OR, 1.811; 95% CI, 1.031–3.181).

This study shows that FFs exhibit a greater likelihood of having FJD than HOWs after controlling for other risk factors of FJD. This suggests that the physical occupational demands of FFs affect their risk of developing FJD.