SNORING, SLEEP-APNEA AND CARDIOVASCULAR RISK-FACTORS - THE MONICA-II STUDY

The objective of this study was to evaluate the cardiovascular risk pr ofile in self-reported snorers and sleep apnoeics in an adult represen tatively-selected population. A total of 1504 males and females, aged 30, 40, 50 and 60 years were included. The following were measured: sn oring, alcohol and tobacco consumption by questionnaire, blood pressur e, serum high density lipoprotein (HDL) and total cholesterol. Nocturn al respiration was determined in 748 participants. Respiratory distres s index (RDI) was defined as the number of apnoea and hypopnoea lastin g longer than 10 seconds per hour sleep. Habitual snoring was reported by 19.1% (9.2-24.2%, aged 30-60 years) of males and 7.9% (3.8-11.7%), age 30-60 years) of females. An RDI greater-than-or-equal-to 5 was fo und in 10.9% (7.1-18.3%, age 30-60 years) of males and in 6.3% (5.3-7. 6%, age 30-60 years) of females. The following factors were associated with snoring: age (P < 0.02), sex (P < 0.001), body mass index (BMI) (P < 0.0001), alcohol (P < 0.05) and tobacco (P < 0.01) consumption. A n RDI greater-than-or-equal-to 5 was associated with sex (P < 0.001), age (P < 0.05), BMI (P < 0.0001), tobacco (P < 0.02) and alcohol (P < 0.05) consumption. Self-reported snorers showed higher systolic (P < 0 .001) and diastolic (P < 0.001) blood pressure and total cholesterol ( P < 0.001) and a lower HDL (P < 0.001). The participants with RDI grea ter-than-or-equal-to 5 showed higher systolic and diastolic blood pres sure (P < 0.001) and total cholesterol (P < 0.001). Significant correl ations were found between BMI and blood pressure (P < 0.0001), total c holesterol (P < 0.0001) and HDL (P < 0.0001). The relation between RDI , self-reported snoring, blood pressure and HDL-cholesterol became non -significant in the multivariate analysis when age, sex, BMI, alcohol and tobacco consumption were taken into account. We conclude that snor ing and sleep apnoea are associated with major cardiovascular risk fac tors, including BMI, alcohol and tobacco consumption. The relation bet ween snoring, sleep apnoea and blood pressure was not significant when controlling for BMI. Sufficient control of the confounders is thus es sential in studies on snoring, obstructive sleep apnoea and the risk o f cardiovascular diseases.