Abstract
STUDY OBJECTIVES: The relationship among obstructive sleep apnea (OSA), body mass index (BMI), and testosterone levels has long been suggested. Obese men have shown a negative correlation between testosterone level and sleep apnea severity. Yet, little is known about the association between testosterone levels and sleep apnea in men who are not obese. This study evaluated the association between the total testosterone (TT) level and OSA in patients who are not obese. METHODS: A retrospective review of 523 records of patients in whom OSA was diagnosed from 2013-2016 was performed. The study included men with a BMI < 30 kg/m(2) and with TT levels measured in a blood sample collected the morning after a sleep study. RESULTS: In all, 153 nonobese men met inclusion criteria, of whom 47 (30.7%) had testosterone levels below the reference values; 44 of these individuals (93.6%) were overweight (P = .029). Reduced testosterone levels showed significant correlations with the oxygen desaturation index, the lowest oxygen saturation < 80% (O(2) nadir < 80%), and rapid eye movement (REM) sleep duration, after adjusting for BMI. Among patients with normal weight, only 3 who had O(2) nadir < 80% and were older than 50 years presented with a reduced TT level. CONCLUSIONS: In a large population of nonobese men with OSA, we demonstrated that hypoxemia (O(2) nadir < 80%) and overweight are associated with reduced testosterone levels. This association was only observed among normal-weight individuals older than 50 years.