Sleep Apnoea May Be Linked To Hypothyroidism, Study Finds

Obstructive sleep apnoea (OSA) is estimated to affect up to 10 million people in the UK, with about four million of those with the condition believed to have moderate to severe cases.

Untreated OSA, which can manifest as very loud snoring, pausing breathing during sleep, and daytime fatigue, has been linked to higher blood pressure and increased risk of stroke, type 2 diabetes, and even depression.

And now, researchers think it could be associated with hypothyroidism too.

This is the medical term for an underactive thyroid.

The thyroid is a butterfly-shaped gland in your neck that produces some hormones, particularly those that influence your metabolism (how your body uses fuel), energy levels, temperature, and heart rate.

And when the thyroid isn’t as active as it should be, those with the issue can experience symptoms like weight gain and fatigue. But these signs aren’t always easy to notice.

However if left untreated, hypothyroidism could eventually harm the heart and bones.

If you suspect you might have an underactive thyroid, it’s best to see your GP who can run blood tests.

A paper published in the journal Sleep looked at data from 761 São Paulo participants. They underwent laboratory tests and polysomnography (a sleep test).

After observation, scientists found that about 12.6% of participants had OSA. And among those with it, almost half (49.5%) had hypothyroidism, too.

Only an estimated 5% of the general population is believed to have the thyroid issue.

Ellen Maria Sampaio Xerfan, the study’s lead author, said: “We expected the prevalence of sleep apnoea to be considerable among people with hypothyroidism, but the result was higher than we’d imagined.

“Studies in the literature typically report figures averaging between 30% and 40%, but we found that nearly half of our participants had both conditions.”

This study didn’t explain why the two might co-occur, though it did show that people with hypothyroidism who took the appropriate medication slept better and more deeply.

Xerfan added: “Sleep and the thyroid are linked to fundamental mechanisms of homeostasis.

“There’s a complex interaction between the two systems, and sleep disturbances can influence hormonal regulation just as thyroid dysfunction can affect sleep quality.”

The study concluded: “These findings underscore the importance of incorporating early thyroid function screening into the care of individuals with OSA and, conversely, evaluating patients with thyroid dysfunction for OSA.”