An Argument for Lowering Thyroid Medication, Closer Thyroid Monitoring After Menopause

This study found a twofold to threefold increased risk of fracture in people over age 70 on higher doses of thyroid replacement, especially over 0.093 mg per day. In the past, high thyroid replacement doses have been shown to be related to lower bone density and other risk factors for falls and fractures.

Bone fractures are rough on older people, and that’s why a study showing excess doses of thyroid hormone replacement are related to bone fractures should give you and your doctor pause. Closer monitoring of your thyroid dose and a reassessment of the dose that worked well for you for years should be considered.

Doctors are learning that after menopause, your body does not need as much thyroxine (the main hormone in the thyroid gland), which bolsters your metabolic rate and growth.

In a large population-based retrospective study of nearly ¼ million Canadians over age 70 using thyroid replacement therapy, aka levothyroxine (88 percent were women) thyroid replacement therapy in Ontario, Canada, Lorraine Lipscombe, MD, assistant professor of medicine at endocrinology at Women’s College Hospital, Toronto, and coauthors looked at the effect of thyroid replacement dose on fractures of the wrist, forearm, shoulder, spine, pelvis, hip or femur, or lower leg or ankle.

As the study authors point out, hypothyroidism is usually diagnosed in early or middle adulthood and older people taking thyroid replacement therapy have been taking it for decades when they reach older age. Furthermore, people are often on the same dose for years. If a woman requires less thyroid replacement, but is overtreated, she may develop iatrogenic hyperthyroidism, meaning that the hyperthyroidism was caused by excess dosing.

The study also begs the question as to whether reference ranges for “normal” TSH levels are appropriate for older people and groups other than Caucasians. Thus far, studies in these populations has been limited. Funding such studies should be a top priority for health care researchers.

The study, published in the BMJ, is important because prescription of thyroid replacementtherapy is widespread; millions of people take thyroid replacement therapy for hypothyroidism in generic and brand formulations. They are top drugs purchased in the US. The study follows others showing increases in fracture. Overdosing of thyroid replacement therapy has also been associated with heart risks, such as atrial fibrillation.

As people ponder whether healthcare reform can help or harm in the United States, it is worth underscoring that healthcare research on large unified population database studies like those in Canada is much easier to perform because the entire population is covered under a single payer. Research is also far cheaper administratively.

This entry was posted in elderly, fractures, monitoring, thyroid disorders and tagged , , , , , . Bookmark the permalink.

2 Responses to An Argument for Lowering Thyroid Medication, Closer Thyroid Monitoring After Menopause

  1. Beth says:

    Thanks for highlighting this in your blog, Laura. This finding is not so surprising since there’s a huge literature on the cross-talk between thyroid hormones and estrogens. But it’s good that researchers are asking this sort of “real life” question and that you are helping to disseminate the answers.

  2. Stephanie says:

    Thanks for your comments on the thyroid replacement therapy. I am one of those people who has been taking thyroid medication for years, based on several TSH tests that I took when in my 30’s. My TSH level was very high and so I was started on Synthroid. My Synthroid level has varied dramatically over the years from .1 mg to .2 mg. Right now I have stabilized on .125 mg. It has been at this level for about 10 years. I am now approaching 65 years old, so your article got me to thinking. Right now my TSH is in the “normal” range. Should we let the TSH level go to the “high” range in menopause? My doctor is quite vigilant about getting this test done. I would appreciate the citation to the published clinical studies that show greater fractures in women over 70 who are taking thyroid hormone with TSH levels in the “normal” range. Thanks.

Comments are closed.