Thyroid disease and osteoporosis: Why women with hypothyroidism are at a greater risk

Health risks of thyroid diseases: Thyroid hormones play a major role in bone metabolism. Both hyperthyroidism and improperly managed hypothyroidism can lead to bone loss (Image: Canva)

Thyroid disorders, particularly hypothyroidism, are often linked with fatigue, weight changes and mood swings, but there's more to worry about than what meets the eye. For many women, thyroid dysfunction silently undermines bone health, increasing the risk of osteoporosis and fractures. This connection is especially critical in post-menopausal women, where bone density is already on the decline.

The thyroid gland produces hormones vital for regulating numerous bodily processes, including bone turnover, shares Dr Sheila Shaikh, Endocrinologist at Saifee Hospital, Mumbai. “Thyroid hormones play a major role in bone metabolism. Both hyperthyroidism and improperly managed hypothyroidism can lead to bone loss. While hyperthyroidism directly increases bone breakdown, hypothyroidism, if not carefully treated, can also contribute to compromised bone quality,” she explains.

Dr Shaikh suggests ways in which these conditions impact bone health:

Also read | Thyroid disorders: Everything you need to know about hypothyroidism and hyperthyroidism

• Hyperthyroidism leads to rapid bone turnover: An overactive thyroid increases the release of hormones that speed up bone resorption. “In hyperthyroidism, the body breaks down bone faster than it can rebuild it. This high bone turnover leads to weakened bones and increases the likelihood of osteoporosis. Even subclinical hyperthyroidism, where TSH is normal but T3 and T4 are elevated, may have a similar effect,” says Dr Shaikh.

• Faulty hormone replacement in hypothyroidism can trigger bone loss: In hypothyroid patients on levothyroxine, overcorrection can lower TSH too much, resulting in bone loss. “Aiming for too low a TSH can be dangerous. Bone health must be regularly monitored during treatment. Careful titration of hormone therapy is vital to prevent iatrogenic osteoporosis,” cautions Dr Shaikh.

• Autoimmunity affects bone remodelling: Since hypothyroidism is often autoimmune in origin (e.g., Hashimoto’s thyroiditis), the inflammatory processes can alter normal bone remodelling. “Though hypothyroidism might initially increase bone mass, it leads to poor bone quality and osteosclerosis, increasing fracture risk,” informs Dr Shaikh.

• Temporary bone loss during treatment: When hypothyroidism is treated with levothyroxine, there can be a brief phase of bone loss. “Bone mineral density usually stabilises after some time. It’s important not to panic but to ensure regular bone health checks,” says Dr Shaikh.

• General bone health measures are essential: Thyroid patients must proactively support their bones through lifestyle choices. Dr Shaikh suggests, “Ensure a diet rich in calcium and vitamin D, include weight-bearing exercises, and avoid smoking or excessive alcohol. These small changes make a big difference,” she says.