Vol.:(0123456789) 1 3 Sleep and Biological Rhythms https://doi.org/10.1007/s41105-019-00220-5 ORIGINAL ARTICLE Predictors of objectively measured snoring in a working population Tomokazu Furukawa 1  · Hiroshi Nakano 1  · Kazufumi Yoshihara 2  · Nobuyuki Sudo 2 Received: 2 December 2018 / Accepted: 27 March 2019 © Japanese Society of Sleep Research 2019 Abstract Although there have been many epidemiological studies of snoring, most did not assess snoring objectively. The aim of this study was to identify predictive factors for snoring measured objectively in a working population in Japan. We used IC recorders for the overnight tracheal sound monitoring of 191 employees of two facilities for two nights. Snoring was characterized by two variables: snoring time (%ST) as a percentage of recording time, and the mean tracheal sound energy during recording time (Leq, the equivalent sound pressure level). After excluding those with insufcient data, 172 subjects were included in the fnal analysis [124 men; age, 44.3 ± 9.9 years; body mass index (BMI), 22.9 ± 3.7 kg/m 2 ]. Relationships between the two snoring variables and age, sex, BMI, drinking, smoking, and night nasal congestion were evaluated, and the predictors of snoring were identifed using multiple regression analysis with %ST and Leq as the dependent variables. The mean values of %ST and Leq were 7.4 ± 7.4% and 102.1 ± 5.2 dB, respectively. Multiple regression analysis revealed that BMI (p < 0.001), night nasal congestion (p = 0.007), habitual drinking (p = 0.014) were signifcant predictors of %ST and that being male (p < 0.001) and BMI (p = 0.007) were signifcant predictors of Leq. These results suggested that being male, obesity, habitual alcohol consumption, and night nasal congestion are predictors of objectively measured snoring in a working population. Keywords Snoring · Tracheal sound monitoring · Acoustics · Predictors · Working population Abbreviations %ST Snoring time as a percentage of recording time Leq Equivalent sound pressure level BMI Body mass index TS Tracheal sound Introduction Snoring is an acoustic phenomenon caused by the vibration of pharyngeal soft tissues surrounding the upper airway, pre- dominantly during inspiration. Habitual snoring has a high prevalence in the general population. Snoring is a principal symptom of obstructive sleep apnea, and self-reported snor- ing has been used as a surrogate marker in epidemiological studies that investigated the relationship between obstruc- tive sleep apnea and cardiovascular disease. However, there is growing evidence that the snoring itself may contribute to health consequences. Lee et al. reported an association between heavy snoring and an increased risk of carotid ath- erosclerosis, which was independent of other risk factors including the severity of obstructive sleep apnea [1]. Our previous study showed that the sound intensity of snoring was signifcantly associated, independently of sleep apnea, with excessive daytime sleepiness [2], daytime blood pres- sure [3, 4], and morning blood pressure [5]. Furthermore, snoring can have a major impact on health outcomes for the bed partners of the snorers. Prevention of snoring is, there- fore, an important public health issue. Various risk factors for snoring have been reported by past studies, including obesity [6–10], male sex [6], age [7–10], alcohol intake, smoking [7, 8, 10, 11], menopause [12], craniofacial morphology [13], sleeping position [8], hypnotic drug use [14], nocturnal nasal congestion [15], family history [16], asthma [6, 15], and physical inactiv- ity [8]. In these studies, however, snoring severity and fre- quency were evaluated by questionnaires. To the best of our knowledge, only two epidemiological studies have assessed * Tomokazu Furukawa tfurukawa2011@gmail.com 1 Sleep Disorders Center, National Hospital Organization Fukuoka National Hospital, 4-39-1, Yakatabaru, Minami-ku, Fukuoka City 811-1394, Japan 2 Department of Psychosomatic Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan