Relationships Of Snoring Habits With Cardiovascular Disease And Its Metabolic Risk Factors

ObjectiveThis study aims to investigate the relationship between snoring and metabolic risk factors of cardiovascular diseases,including hypertension,hypercholesterolemia,hypertriglyceridemia,low high-density lipoprotein cholesterol(HDL-C)and diabetes,as well as the impact on the risk of cardiovascular disease.MethodsData from the 15 population samples attended for the China Multicenter Collaborative Study of Cardiovascular Epideliology(China MUCA)conducted from August to December 1998 were used.Approximately 1000 men and women aged 35 to 59 years in each population were selected.Participants were collected for cardiovascular risk factors,including to ask participants’ snoring habits(snoring frequency,snoring sound intensity).After the end of the baseline sxirvey,14 population groups were followed up(one study center did not participate in the follow-up study),with the longest follow-up to the end of 2015.Participants were divided into four groups according to the frequency of snoring:non-snoring,sometimes(1-2 times/week),often(3-5 times/week)and always snoring(6-7 times/week).In addition,participants were also divided into four groups according to the snoring sound intensity:non-snoring,mild(just slightly louder than the breath or about the size of the voice),moderate(louder than the voice),and severe(especially loud through closed doors).Logistic regression models were used to investigate the relationship between snoring and metabolic risk factors of cardiovascular disease;and Cox proportional hazards models were used to investigate the relationship between snoring and the risk of cardiovascular events.ResultsA total of 15,573 people participated in the baseline survey of ChinaMUCA,with a response rate of 85.1%.In the cross-sectional analysis,701 people were excluded because they did not know whether they snored or not,753 people lacking blood samples,and 8 people were excluded because their height,weight or waist circumference was not obtained.Thus,a total of 14,111 subjects(6,697 males and 7?414 females)were included in the cross-sectional study for analyzing the relationship between snoring and hypertension,hypercholesteremia,low HDL-C,hypertriglyceridemia and diabetes.In addition,1058 people were further excluded in the analyzing the relationship between snoring and diabetes since the blood glucose level of one group of people did not meet the quality control requirements,which resulting in 13053 people were remained in the analysis of relationship between snoring and diabetes.A prospective follow-up study was conducted after the baseline survey,with the longest follow-up until the end of 2015.After excluding a group of 944 people who did not participate in the follow-up,10 people were loss of follow up,and 136 people who had cardiovascular events at baseline,there were 11,963 people were finally included in the analysis of the relationship between snoring and cardiovascular events.The results of cross-sectional analysis showed that the prevalence of hypertension in different snoring frequency groups were 18.0%in non-snoring group,28.6%in sometimes snoring group,37.3%in frequently snoring group,and 40.9%in always snoring group,showing a significant upward trend(P for trend P<0.001).With the increase of snoring frequency,the prevalence of hypertension,hypertriglyceridemia,hypercholesteremia,low HDL-C and diabetes were also significantly increased(all P values for trend<0.001).With the increase of the sound intensity of snoring,the prevalence of metabolic risk factors of cardiovascular diseases also showed significant increasing trends(all P for trend<0.001),the prevalence of hypertension was 18.0%in non-snoring group,30.3%in mild group,35.6%in moderate group and 43.1%in severe group.Logistic regression analysis adjusted for age and gender showed that both the frequency and intensity of snoring were significantly and positively correlated with metabolic risk factors of cardiovascular diseases.The relationship between snoring frequency,snoring sound and metabolic risk factors remained significant when we additionally adjusted for urban or rural,education levels,smoking,drinking,family history of hypertension/diabetes.The results were not altered after further adjustment for body mass index(BMI).Compared with non-snorers,the risk of hypertension(OR and 95%CI)in the sometimes,often,and always snoring groups were 1.23(1.11-1.37),1.50(1.32-1.72)and 1.55(1.33-1L81),P for trend<0.001.The risk of hypertension(OR and 95%CI)in mild,moderate,and severe groups werel.27(1.15-1.41),1.46(1.28-1.68)and 1.59(1.32-1.90),respectively,P for trend<0.001.However,after further adjustment for BMI,the relationship between snoring and low HDL-C,hypercholesteremia were no longer significant(P for trend>0.05).A total of 11963 people were included in the prospective analysis.After a medimi follow-up of 13.9(6.7,15.1)years,a total of434(3.6%)cardiovascular events(including coronary heart disease morbidity or mortality,fatal or non-fatal stroke,and sudden cardiac death)occured,including 318 stroke events and 123 coronary heart events.The incidence of cardiovascular events in non-snoring,sometimes,frequently,and always snoring group were 2.42,3.30,5.71 and 5.79 per 1000 person-years,respectively.After adjustment for age and gender(model 1),the frequency of snoring was significantly and positively correlated with the risk of cardiovascular events.After further adjustment of urban or rural,north or south,educational levels,smoking and drinking status(model 2)on the basis of model 15 this relationship still existed.On the basis of model 2,overweight/obesity(model 3),hypercholesteremia(model 4),hypertriglyceridemia(model 5),low HDL-C(model 6)or diabetes(model 8)was farther adjusted separately,the frequency of snoring was also related with the risk of cardiovascular events significantly.However,the relationship between snoring frequency and the risk of cardiovascular events was not significant when hypertension was further adjusted(model 7)on the basis of model 2.Further more,no significant relationship was found between the frequency of snoring and the risk of cardiovascular events when overweight/obesity,hypercholesteremia,hypertriglyceridemia,low HDL-C,diabetes and hypertensionwere further adjusted(model 8).Compared with non-snoring group,the risk(HR and 95%Cl)of cardiovascular events in the sometimes,often and always snoring groups were0.93(0.72-1.19),1.25(0.94-1.64),and 1.08(0.79-1.46),respectively.The results showed that the sound intensity of snoring was significantly and positively correlated with the risk after further adjusting for hypertension(model 7)on the basis of model 2.Although the risk of cardiovascular events was significantly increased in severe snoring group(RR=1.41,95%CI:1.02-1.94)when we further adjusted for overweight/obesity,hypercholesteremia,hypertriglyceridemia,low HDL-C,diabetes and hypertension(model 9),the trend test for the relationship between the sound intensity of snoring and the risk of cardiovascular events was not significant(P for trend=0.0673).ConclusionSnoring(including frequency and sound intensity of snoring)is independently and positively correlated with the risk of hypertension,diabetes and hypertriglyceridemia in middle-aged Chinese population.Snoring is also positively associated with high hypercholesteremia and low HDL-C,but the association is not independent from BMI.In addition,snoring frequency and snoring sound intensity were also positively associated with the risk of cardiovascular events,but the association was not independent from some metabolic risk factors such as hypertension.