Obstructive Sleep Apnea May Increase Osteoporosis Risk

Jennifer Garcia

April 16, 2014

Patients with obstructive sleep apnea (OSA) are more than twice as likely to develop osteoporosis as patients without OSA, even when adjusting for age, comorbid conditions, income, and geographic location, according to a population-based study in Taiwan. Results of this longitudinal study were published online April 15 in the Journal of Clinical Endocrinology and Metabolism.

Kai-Jen Tien, MD, from the Division of Endocrinology and Metabolism, Chi Mei Medical Center, Tainan, Taiwan, and colleagues evaluated data from 1377 patients identified from Taiwan's National Health Insurance database. Patients were diagnosed with OSA between 2000 and 2008 and were followed-up until a diagnosis of osteoporosis, death, or the end of 2011. The researchers compared these patients with an age- and sex-matched cohort of 20,655 patients without OSA.

The researchers found that patients with OSA had an incidence rate ratio of 2.52 for developing osteoporosis when compared with patients without OSA (95% confidence interval [CI], 1.59 - 3.99; P < .0001). The hazard ratio was 2.74 (95% CI, 1.69 - 4.44; P < .05) when adjusted for "age, gender, diabetes, hypertension, coronary artery disease, obesity, stroke, hyperlipidemia, chronic kidney disease, gout, monthly income, and geographical location."

"This study is the first and largest population-based cohort study to evaluate the association of OSA and osteoporosis in a 6-year follow-up investigation of an Asian population," Dr. Tien and colleagues write.

The researchers go on to note that "[t]he strength of this investigation is that it is a population-based study of a large, nationally representative sample and that it selected only patients who had received dual-energy X-ray absorptiometry prior to being diagnosed with osteoporosis and a polysomnography study prior to being diagnosed with OSA."

In addition, as part of a subgroup analysis, the researchers found that older patients and female patients had the highest risk for osteoporosis when compared with male and younger patients.

Although the exact mechanism remains unclear, the authors cite previous studies that have shown that the repetitive hypoxia of OSA, as well as the presence of inflammatory mediators, may affect bone metabolism and induce osteoporosis.

The authors acknowledge possible study limitations, such as failure to evaluate the effect of OSA in different bone regions and the lack of patient data pertaining to family history of osteoporosis, daily activity, tobacco use, or dietary habits.

"The exact mechanism underlying how OSA affects the bone metabolism...remains unknown," note Dr. Tien and colleagues. However, "[p]hysicians treating patients with OSA should be mindful of this association."

The authors have disclosed no relevant financial relationships.

J Clin Endocrinol Metabol. Published online April 15, 2014.


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