Why am I shrinking?
Not a day goes by that a patient voices a concern about her loss of height. It is not unusual to lose up to two inches after menopause.
We know that loss of vertebral height from osteoporosis fractures is one cause, but many patients who do not have osteoporosis of the spine also experience loss of height. As one of my colleagues put it, “your discs go from marshmallows to pancakes.” Simplistic yes, but it gets the point across. In the October, 2017, issue of Menopause,a study was reported that looked at intervertebral discs in men and women by MRI. The data seems to suggest that there is an increase in deterioration in the discs of the lumbar spine in women in the first 15 years after menopause which is independent of the aging process. This deterioration may contribute to increased vertebral fractures as the “cushion” between vertebrae is degraded.
What causes this deterioration? We know that there is deceased connective tissue such as collagen, as well as loss of water in the discs. Estrogen can preserve some of the collagen and molecules that hold water.
The impact of vertebral fractures is tremendous. It is thought that 15-20% of women in their 60’s will sustain a vertebral fracture, and 50% of women aged 80-84 have sustained a fracture.
Only about one third of fractures are diagnosed. Vertebral fractures, as hip fractures, are associated with increased mortality which extends up to 20 years.
The morbidity of vertebral fractures includes severe pain, decreased mobility, and an increased fall risk due to a change in a person’s center of gravity. Kyphosis (which is the curve of the spine forward) can cause problems with breathing and eating, and can lead to increased bouts of pneumonia .
Vertebrae are most susceptible in the anterior portion of the bone. A movement as simple as bending over can compress a vertebrae, and once one is fractured, it puts more force on adjacent vertebra, causing a domino effect. The decreased cushioning of the shrunken discs adds to the increased risk of fractures.
The chemical composition of the intervertebral disc is complex, as it contains various types of connective tissue and molecules that hold on to water. The vertebral column is a fascinating structure that must adapt to changes in muscle activity and heavy loads that must distribute the pressure evenly along the spine. When the chemical structure of the disc changes with age and menopause, tears and clefts in the discs weaken them which increases the degradation. There is some evidence that a reversal of some of these changes may occur with estrogen. Studies have shows that intervertebral discs have estrogen receptors, and that fibrous cells of the discs proliferate in the presence of estrogen. Estrogen also increases the collagen in bone which is an important factor in the prevention of osteoporosis.
Women who remain on estrogen after menopause have higher disc heights than women not on estrogen. We also know that estrogen prevents osteoporosis. It is becoming more clear that the genesis of vertebral fractures depends on not just the vertebral bone, but the cushions supporting them. Although more studies need to be done, this is fascinating science that explains why we seem to be shrinking!
Menopause: The Journal of the North American Menopause Society, October, 2017,
Editorial: Menopause and the Intervertebral Disc, Yves Muscat Baron, M.D.