OBJECTIVE: We investigated the associations of nocturnal oxygen saturation (SpO DESIGN: Observational study. SETTING: Kusatsu, Shiga. PARTICIPANTS: We analysed data from 510 Japanese men (aged 46-76 years) with no history of myocardial infarction. PRIMARY AND SECONDARY OUTCOMES: Mean SpO RESULTS: Mean±SD age was 66.7±7.2 years. The prevalence of CAC was 64.7% (CAC scores>
0-100, 31.4%
>
100-400, 20.0% and>
400, 13.3%). In multivariable binary logistic regression, the OR and 95% CI for the prevalence of CAC were 1.25 (1.02 to 1.53) per 1-SD decrement in mean SpO CONCLUSIONS: Lower mean SpO