Sleep Apnea and Neck Circumference in Japanese Rugby Union Athletes

Abstract

Objective: The body size of football players may potentially influence high-level performance. However, increased body mass may increase sleep apnea risks. This study investigated the severity of obstructive sleep apnea (OSA) and body composition among Japanese rugby union players. Methods: Subjects were 52 Japanese male rugby union players. The team received routine dental support at the Nihon University School of Dentistry in Matsudo, Japan. Dental services included dental checkups and treatment, and provision of custom-made mouthguards. Outcome measures were the respiratory disturbance index (RDI) recorded from a sleep apnea test and body mass index (BMI), neck circumference (NC) measurements, and the Epworth Sleepiness Scale (ESS). All players were informed of the outcome of the sleep apnea test following completion of assessments, after which eight players desired and received treatment with a monoblock mandibular advancement device (MAD). Results: OSA was seen in 86.5% of players (29 mild, 14 moderate, 2 severe), with only seven players free of OSA. All players were obese according to BMI, with a large NC (mean, 42.5±3.7 cm). Players with moderate and severe OSA exhibited significantly higher BMI and NC than the normal group (p=0.05 and p=0.02, respectively). NC and BMI correlated positively with RDI and snoring episodes, but negatively with minimum and mean peripheral oxygen saturation. The Youden index (NC cut-off, 40.75 cm) indicated increased OSA risk in 32.7%. Daytime ESS score was high (mean, 11±3.9). MAD treatment in eight of the players with OSA significantly improved RDI. Conclusion: OSA was identified in 86.5% of rugby players, with potential contributions from the large NC and characteristic facial morphology of Japanese individuals. During dental care for athletes, dentists may be able to identify sleep-related disorders.