Sleep Apnea Could Affect Bone Health

Obstructive sleep apnea associated with risk of osteoporosis

(RxWiki News) Sleep apnea has been linked to disease of the immune system and inflammatory diseases. But there's one part of the body possibly affected by sleep apnea that many may not even consider.

A recent study found that patients with obstructive sleep apnea (when breathing continuously stops and starts while sleeping) were at increased risk of developing osteoporosis (chronic bone disease in which bones become fragile) compared to patients without obstructive sleep apnea.

The researchers believe that doctors treating obstructive sleep apnea should be aware of this association with osteoporosis.

"Discuss the risks of bone disease with a doctor if you have sleep apnea."

The lead author of this study was Kai-Jen Tien, MD, from the Division of Endocrinology and Metabolism in the Department of Internal Medicine at Chi Mei Medical Center and the Center of General Education at Chia Nan University of Pharmacy and Science — both in Tainan, Taiwan.

The study included 1,377 patients aged 40 years and older who were diagnosed with obstructive sleep apnea between 2000 and 2008 in Taiwan.

Forty-five percent of the sleep apnea patients were between the ages of 40 and 49 years old, and 17 percent of the patients were white.

None of the patients were diagnosed with sleep apnea before 2000, and none of them were diagnosed with osteoporosis before being diagnosed with obstructive sleep apnea.

There was also a control (comparison) group of 20,655 age- and sex-matched patients who did not have obstructive sleep apnea.

The Longitudinal Health Insurance Database 2000 was used to identify the gender, date of birth, dates of hospital admission and discharge, diagnoses, medicine prescriptions and medical outcome of each patient.

The researchers conducted follow-up for an average of six years.

The findings showed that 21 sleep apnea patients were diagnosed with osteoporosis, with an incidence rate of 2.5 cases per 1,000 person-years (number of people multiplied by number of years until osteoporosis diagnosis, death or the end of 2011).

Among the control group, 126 patients were diagnosed with osteoporosis. The incidence rate for the control group was 1.0 cases per 1,000 person-years.

The researchers determined that the patients with obstructive sleep apnea were 2.7 times more likely to be diagnosed with osteoporosis during the study period than patients in the control group.

This increased risk was independent of age, gender, diabetes, high blood pressure, coronary artery disease, obesity, stroke, hyperlipidemia (too much fat in the blood), chronic kidney disease, gout (a form of arthritis), monthly income and geographical location.

Compared to the all patients who were between 40 and 49 years old, those between 50 and 64 years old and those 65 years old and older were 2.3 and 5.8 times more likely to be diagnosed with osteoporosis.

The female patients were 8.7 times more likely to develop osteoporosis compared to the male patients.

“Ongoing sleep disruptions caused by obstructive sleep apnea can harm many of the body’s systems, including the skeletal system,” said Dr. Tien. “When sleep apnea periodically deprives the body of oxygen, it can weaken bones and raise the risk of osteoporosis. The progressive condition can lead to bone fractures, increased medical costs, reduced quality of life and even death.”

The researchers noted a few limitations of their study.

First, bone mineral density in the sleep apnea group was not compared with that of the control group. Second, the researchers did not assess risk factors of osteoporosis such as the patients' family history of osteoporosis, daily activity, eating habits or tobacco use. Third, there may have been undiagnosed cases of obstructive sleep apnea in the control group.

This study was published on April 15 in The Journal of Clinical Endocrinology & Metabolism.

Review Date: 
April 15, 2014