Loud Snoring Predicts Metabolic Syndrome

By Cole Petrochko, Staff Writer, MedPage Today
December 02, 2010
MedPage Today Action Points

Explain that patients with sleep symptoms such as difficulty falling asleep, unrefreshing sleep, and loud snoring are at higher risk for developing metabolic syndrome.

Review

Patients with sleep symptoms are at higher risk for developing metabolic syndrome, a prospective study found.

Difficulty falling asleep, snoring loudly, and unrefreshing sleep were significant predictors of metabolic syndrome (P<0.05). Snoring doubled the risk, while difficulty falling asleep increased the risk by 80%, Wendy Troxel, PhD, of the University of Pittsburgh, and colleagues reported in Sleep.

Loud snoring also was associated with doubled risks of other metabolic abnormalities, and remained a significant metabolic syndrome predictor after further apnea-hypopnea index (AHI) adjustment, whereas other sleep symptoms were only marginally significant, the researchers noted.

The study evaluated 2,000 patients enrolled in an ongoing, community-based prospective heart health study. Patients were ages 45 to 74, lived in or around the Pittsburgh metropolitan area, and had no comorbidity limiting life expectancy to less than five years.

Exclusion criteria included non-black or non-white race, presence of metabolic syndrome or diabetes at baseline, and missing sleep or covariate data at baseline.

The final sample included 812 patients, with a subset of 294 patients agreeing to undergo further evaluation at home in a follow-up analysis adjusted for AHI.

The primary outcome was the presence or absence of metabolic syndrome at the three-year follow-up. Waist circumference, fasting glucose, and lipids were measured at baseline and annually for three years.

Patients were given the Insomnia Sleep Questionnaire and the Multivariable Apnea Prediction Questionnaire to evaluate sleep-disordered breathing and insomnia symptoms. Covariate measures included history of smoking, alcohol consumption, physical activeness, and depressive symptoms.



At the three year follow-up, 14% of patients developed metabolic syndrome. After adjustment for loud snoring, difficulty falling asleep remained a significant predictor (OR 1.78, 95% CI 1.05 to 3.02), while unrefreshing sleep showed marginal significance (OR 1.56, 95% CI 0.96 to 2.53).

The significant symptoms also were compared against the AHI. Only loud snoring remained significant as a predictor (OR 3.01, 95% CI 1.39 to 6.55), while difficulty falling asleep was marginal (OR 1.91, 95% CI 0.80 to 4.58).

Researchers noted the study was limited by self-reported sleep disturbance and lack of sleep duration measures. The AHI analysis was limited by small subsample size and the cross-sectional nature of the AHI assessment.

Healthcare professionals should look for common sleep symptoms while assessing a patient due to the measured health risks associated with some symptoms, the researchers concluded, adding that future research could look at subjective sleep complaints and psychological factors affecting patients' poor sleep related to cardiovascular morbidity and mortality.