TOPLINE:
Hypothyroidism increases with increasing lymphocytes in patients with obstructive sleep apnea (OSA).
METHODOLOGY:
- A total of 920 adults with OSA (879 with normal thyroid and 41 with hypothyroidism) underwent nocturnal sleep monitoring, thyroid function testing, and routine blood work.
- Logistic regression analysis was used to show predictors of hypothyroidism.
- Lymphocyte counts were identified via receiver operating characteristic curve analysis.
TAKEAWAY:
- Overall, lymphocyte counts were significantly higher in individuals with hypothyroidism than in control individuals (P = .002).
- Men with hypothyroidism had significantly higher lymphocyte levels than those with normal thyroid function and OSA (P = .020); counts were higher in women with hypothyroidism, but the difference was not significant.
- Men with elevated lymphocyte levels were more likely to experience sleep apnea and oxygen reduction events compared with control individuals without elevated lymphocytes.
- Epworth Sleepiness Scale scores were significantly higher in both men and women with hypothyroidism.
IN PRACTICE:
"A simple blood test for lymphocyte count could indicate the occurrence of hypothyroidism in OSA patients, proving valuable in clinical practice," the researchers wrote.
SOURCE:
The lead author on the study was Xiaoyan Fang, MD, of Tianjin Medical University General Hospital, Tianjin, China. The study was published online on January 27, 2024, in BMC Pulmonary Medicine.
LIMITATIONS:
Study limitations included the small sample size because of the exclusion of some patients with OSA, the lack of long-term follow-up, and the lack of evaluation of continuous positive airway pressure or hormone supplementation on lymphocyte levels.
DISCLOSURES:
The study was supported by the Natural Science Foundation of China and the Bethune Fund for Scientific Research Project. The researchers had no financial conflicts to disclose.