RESUMO
OBJECTIVE: The main objective of this study was to investigate, in a population of normal postmenopausal women, the association between menopause and severity of lumbar disc degeneration from the first lumbar to the first sacral vertebra on magnetic resonance imaging. METHODS: Between January 2010 and May 2013, 846 normal women and 4230 intervertebral discs were retrospectively analyzed. Age, height, weight and years since menopause (YSM) were recorded. Disc degeneration was evaluated using the modified Pfirrmann grading system. RESULTS: Compared to premenopausal and perimenopausal women, postmenopausal women had more severe disc degeneration after removal of age, height and weight effects (p < 0.0001). Postmenopausal women were divided into six subgroups for every 5 YSM. When YSM was below 15 years, there was a significant difference between every two groups, i.e. groups 1-5 YSM, 6-10 YSM and 11-15 YSM (p < 0.01). A positive trend was observed between YSM and severity of disc degeneration, respectively, i.e. L1/L2 (r = 0.235), L2/L3 (r = 0.161), L3/L4 (r = 0.173), L4/L5 (r = 0.146), L5/S1 (r = 0.137) and all lumbar discs (r = 0.259) (p < 0.05 or 0.01). However, when YSM was above 15, there was no difference, i.e. groups 16-20 YSM, 21-25 YSM and 26-30 YSM (p > 0.05), and the significance correlation also disappeared (p > 0.05). CONCLUSION: Menopause is associated with disc degeneration in the lumbar spine. The association almost entirely occurred in the first 15 years since menopause, suggesting estrogen decrease may be a risk factor for lumbar disc degeneration.
