Intervertebral disc height in treated and untreated overweight post-menopausal women

BACKGROUND: The effect of the menopause and HRT on the intervertebral discs has not been investigated. METHODS: One hundred women were recruited, comprising of 44 post-menopausal women on HRT, 33 untreated post-menopausal women and 23 pre-menopausal women. The height of the intervertebral discs between the 12th thoracic vertebra and the 3rd lumbar vertebra was measured by utilizing the bone densitometer height cursors. RESULTS: The untreated menopausal group of women had the lowest total disc height (D1-D3: 1.95 +/- 0.31 cm). This was significantly lower than the pre-menopausal group D1-D3: 2.16 +/- 0.24 cm) and the hormone-treated group (2.2 +/- 0.26 cm) (P > 0.02). The 2nd intervertebral disc consistently maintained a significant difference between the untreated menopausal group (D2: 0.63 +/- 0.13) and the other two groups (pre-menopausal group (D2: 0.72 +/- 0.09 cm) and treated menopausal group (D2: 0.73 +/- 0.12 cm) (P > 0.02). CONCLUSIONS: Estrogen-replete women appear to maintain higher intervertebral discs compared to untreated post-menopausal women. The estrogenic milieu may be relevant because of the significant impact it has on the hydrophilic glycosaminoglycans, the water content, collagen and elastin of the intervertebral discs. The maintenance of adequate disc height may allow the intervertebral discs to retain their discoid shape and viscoelastic function, containing vertical forces which may threaten spinal architecture leading to vertebral body compression fractures.