INSULIN LEVELS, BLOOD-PRESSURE AND SLEEP-APNEA

This report concerns the relative contributions of body weight and sle ep apnea to the following cardiovascular risk factors: blood pressure, fasting insulin and fasting glucose. We cross-sectionally examined th e relationship of various levels of apneic activity [apnea-hypopnea in dex (AHI)] and a measure of obesity [body mass index (BMI)] to mean mo rning blood pressure and fasting serum insulin and fasting blood gluco se concentrations sampled the morning after polysomnography. Subjects were 261 males (age 47 +/- 13 years, mean +/- SD), who were referred t o a sleep laboratory for symptoms of sleep-disordered breathing. The d ependent variables, mean morning blood pressure, insulin and fasting b lood glucose (FBG) levels, were significantly related to both AHI (eta (2) = 0.10) and BMI (eta(2) = 0.18). AHI and BMI combined to account f or approximately 30% of the variability in the best linear combination of these three factors. Further analysis indicated that mean morning blood pressure and fasting insulin levels each correlated positively w ith BMI and AHI, whereas FBG correlated only with BMI. We conclude tha t, although these data do not prove a causal relationship, there is ev idence for an independent association between deep apnea and not only blood pressure, but also fasting insulin levels.