Diastolic blood pressure is the first to rise in association with early subclinical obstructive sleep apnea: lessons from periodic examination screening

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is associated with long-term cardiovascular morbidity. Little is known about these relations at early stages. We conducted a case-control study in which we analyzed the clinical characteristics of young adults who underwent a periodic health examination and were screened for, and eventually found to experience, OSAS. METHODS: We identified 121 subjects newly diagnosed in a sleep study as having OSAS, and 229 matched control subjects in which screening for OSAS was negative. All had a medical interview, physical examination, and routine laboratory tests. RESULTS: Subjects who had OSAS had a higher, body mass index (3-kg/m(2) difference) and a higher diastolic blood pressure (4-mm Hg difference) value, without elevation in systolic blood pressure. There was no metabolic difference (lipids profile and fasting glucose levels) between groups. CONCLUSIONS: Diastolic blood pressure is higher early in the course of OSAS. Long term follow-up may determine effects of prevention and early intervention in OSAS and associated hypertension.