Hypothyroidism patients are more likely to develop sleep apnea, according to new research.
To understand the potential link between hypothyroidism and sleep apnea, a team from Texas Tech University Health Sciences Center (TTUHSC) embarked upon new research using data mined from the National Health and Nutrition Examination Survey (NHANES). Their study, “Hypothyroidism and its Association with Sleep Apnea Among Adults in the United States: NHANES 2007-2008,” was published in July by the Journal of Clinical Endocrinology & Metabolism.
The NHANES is a biennial survey conducted by the Centers of Disease Control and Prevention to generally evaluate the health of children and adults in the US. In addition to providing a significantly larger sample size, the NHANES provides a cross-sectional sample of the non-institutionalized US adult population. It includes a detailed demographic and behavioral questionnaire, a physical examination, laboratory testing and a list of all prescription medications used by the respondent.
Study coauthors internal medicine resident Subhanudh Thavaraputta, MD; Jeff Dennis, PhD, an assistant professor for TTUHSC’s Department of Public Health, looked a the 2007-2008 NHANES because it tested respondents for thyroid stimulating hormone (TSH) levels and included a detailed sleep questionnaire.
“We had to use those two years to get the exact data points that we wanted,” Dennis says in a statement. “I always use the most current data when we can, but we were somewhat constrained here, and this is the one NHANES where we could see both TSH levels and sleep disorder information in the same place. We don’t have any reason to think that would have changed drastically between the 2007-2008 NHANES and now. What we found should be reasonably consistent over time.”
Thavaraputta, the study’s lead author, says responses from 5,515 of the 10,000 respondents who participated in the 2007-2008 NHANES were ultimately included in the TTUHSC research. After analyzing those results, he and Dennis estimate that the prevalence for hypothyroidism among US adults is 9.47%, which represents approximately 19.6 million people.
The results also indicate that individuals diagnosed with hypothyroidism are 1.88 times more likely to develop sleep apnea. Hypothyroid patients who were undergoing hormone replacement therapy at the time of the NHANES evaluation were estimated to be 2.51 times more likely to have a sleep apnea diagnosis, regardless of their TSH level.
“We hope that our findings will raise awareness and concern among physicians regarding this association,” Thavaraputta says. “In the future, if this relationship is established, assessing the sleep qualities/problems in hypothyroid patients might be beneficial to improve the patients’ standard of care, quality of life and treatment outcomes.”