Case-control study of risk factors for lumbar intervertebral disc herniation in Croatian island populations.

Abstract

AIM: To investigate the risk factors for lumbar intervertebral disc herniation (L4/L5 or L5/S1) severe enough to require surgery of the lower spine among 9 isolated populations of Croatian islands and to evaluate predictive value, sensitivity, and specificity of a simple screening test based on the understanding of the risk factors in this population. METHODS: In a sample of 1001 examinees from Croatian island populations, we identified all subjects who underwent surgery of the lower spine due to lumbar intervertebral disc herniation L4/L5 or L5/S1 and selected 4 controls matched by age, gender, and village of residence for each of them. Odds ratio was computed for the following variables: body mass index, occupation, intensity of physical labor at work, intensity of physical labor at home, smoking index, claudication index, self-assessed limitation in physical activity, level of education, socio-economic status, and family history of lumbar intervertebral disc herniation requiring surgery. RESULTS: Comparison of 67 identified cases with 268 controls revealed the highest odds ratios (OR) for positive family history (OR 4.00; 95% confidence intervals [CI], 1.89-6.11, P<0.001), intensity of physical labor at work defined as (hard) (OR 2.94; 95% CI, 1.07-4.81, P<0.001), and body mass index of 25.7 or more (OR 2.77, 95% CI, 1.05-4.49, P=0.002). A simple screening test based on the presence of any two of these three criteria has 74% sensitivity and 82% specificity to detect persons who underwent lower spine surgery due to lumbar intervertebral disc herniation in the population aged 40 years or more. CONCLUSION: Occurrence of lumbar disk herniation severe enough to require surgery of the lower spine can be predicted using a very simple set of criteria. This type of screening could reduce the need for surgery in isolated communities through prevention within primary health care.