Relationship between hip bone mineral density and lumbar disc degeneration: A study in elderly subjects using an eight‐level MRI‐based disc degeneration grading system

PURPOSE: To study the relationship between hip bone mineral density (BMD), lumbar disc degeneration, and lumbar disc space narrowing in elderly subjects. MATERIALS AND METHODS: The study cohort comprised 196 females and 163 males (age range, 67-89 years) with no age difference between the two groups. Anteroposterior total hip areal BMD was measured with DXA and lumbar spine MRI was acquired using a 1.5 Tesla scanner. Lumbar disc degeneration was assessed using an eight-level grading system wherein each grade represents a stepwise progression from normal disc to severe disc degeneration and disc space narrowing. RESULTS: After controlling for the age effect, no significant relationship was observed between total hip T-score status and severity of disc degeneration. There was no significant difference in total hip BMD in the subjects with or without the disc space narrowing (P < 0.05). Female subjects are more likely to have a narrowed disc space than males at all levels, and being statistically significant at L3/4 and L4/5 levels, and with an overall significance of P = 0.007. CONCLUSION: There was no association observed between hip BMD and lumbar disc degeneration. Elderly females were more likely to have a narrowed lumbar disc space than elderly males.