Vertebral endplate change as a feature of intervertebral disc degeneration: a heritability study.

PURPOSE: To study the prevalence of vertebral endplate or Modic change (MC), the progression of MC over a 10-year follow-up and the heritability of MC prevalence in a classical twin study.

METHODS: The study population was recruited from TwinsUK register between 1996 and 2000. MC was evaluated from T2-weighted lumbar magnetic resonance imaging (MRI) at baseline and follow-up. Heritability was estimated using variance components analysis. Baseline MRI with appropriate data was available for 831 twins and follow-up for 436 twins. In total, both baseline and follow-up imaging were available for 347 twins.

RESULTS: Mean age of the study population was 54.1 years (range 45.7-62.5) and females comprised 96%. The prevalence of MC at baseline was 32.1% and at follow-up 48.4%. The incidence of MC during the 10-year follow-up was 21.6% and was highest at L4-5 and L5-S1. MC regressed totally in 3.5% of twins. Twins with prevalent MC at baseline demonstrated a higher incidence of MC at upper lumbar levels during follow-up compared to twins without baseline MC (p = 0.009). Probandwise concordance rates were higher in monozygotic (0.56) than dizygotic twin pairs (0.39) suggestive of familial influence. Heritability of MC prevalence was estimated at 30 (16-43) %.

CONCLUSIONS: The results suggest that MC is generally progressive in middle age and furthermore is heritable. Since MC is associated with disc degeneration, which is also heritable, further work on potential shared mechanisms is needed.