Investigation On The Level Of Serum Vitamin D In Hypertensive Patients With Obstructive Sleep Apnea Hypopnea Syndrome

BackgroundAt present our country is in the period of rapid economic development.Over thepast twenty years, the incidence of cardiovascular disease has also been graduallyrisen,and become the major disease of serious threat to human health in modernsociety. According to the world health organization survey statistics show thatcardiovascular disease mortality has been surpassed the sum of all tumor diseases, sohow to reduce the incidence, morbidity and mortality of cardiovascular disease hasbecome the focus of social attention. Hypertension is a very common type ofcardiovascular disease. In the recent years we have found that obstructive sleep apneaand hypopnea syndrome(OSAHS) is often combined with hypertension,which is thecommon cause of secondary hypertension. OSAHS is one of the independent riskfactors which lead to high blood pressure. The proportion of patients who are OSAHScombining with hypertension is about fifty percent to ninety percent, as well aspatients who are hypertension merging with OSAHS is about thirty percent to fiftypercent.Vitamin D,a fat-soluble steroid precursor, is a necessary nutrient elements in thehuman body, whose main function is to regulate the body’s absorption of calcium andphosphate, and promote bone growth and calcification. A large number of epidemiological studies have found that vitamin D deficiency is very common. Inrecent years the study has found that the biological effect of vitamin D is far morethan traditional cognitive. Vitamin D has been involved in cardiovascular disease,cancer and immune. Epidemiological and clinical studies have shown that vitamin Ddeficiency may be associated with the onset of hypertension. But when hypertensionmerges with OSAHS, the changes of the serum levels of vitamin D and its clinicalsignificance is not clear. This study aims to discuss vitamin D levels and itscorrelation when hypertension is combining with OSAHS.ObjectiveDetermine the serum vitamin D levels of Selected objects. Discuss the change ofvitamin D level and its relation in the patients with hypertension combining withOSAHS. To definite the possibility mechanism of OSAHS associated with vitamin Dlevels through further study.Methods270cases of hypertension patients were selected as the hypertension group,whowere in the first affiliated hospital of zhengzhou university of cardiovascular internalmedicine from July2012to July2013. Patients depending on the combination ofOSAHS were divided into: pure hypertension group and hypertension combinedOSAHS group. According to sleep apnea and hypoventilation index we divided thehypertension combined OSAHS group into three groups: mild OSAHS group73cases (AHI5or higher and <15times/h), moderate OSAHS group68cases (AHI and<15or30times/h), and77cases of severe OSAHS group (AHI30times/h or higher).In our hospital respiratory sleep division,50cases of obstructive sleep apneasyndrome were selected as the pure OSAHS group. At the same time45cases werechoosed as the control group,who were included in the healthy physical examinationin our hospital medical center. All selected objects were recorded gender, age, height,weight, blood pressure and other relevant informations. We detected all of thepatients lipid, glucose and serum25-hydroxyl vitamin D3[25(OH) D3] level. Weanalysised and record sleep apnea and hypoventilation index (AHI),the lowest oxygen saturation (MSPO2) by night polysomnography about seven hours. Using statisticalmethods analysis and processing of the data.Results1．There was no significant difference (P>0.05) of the general clinical date suchas age, total cholesterol(TC), triglyceride(TG), high density lipoproteincholesterol(HDL-C), low density lipoprotein cholesterol (LDL-C), fasting bloodglucose(FBG) in the control group, pure OSAHS group, pure hypertension group andhypertension combined OSAHS group.2．Compared to control group, the differences in body mass index(BMI) and thelevel of25(OH)D3were statistically significant than the other three groups (P<0.05)；There was no significant difference (P>0.05) of the level of25(OH)D3between thehypertension combined OSAHS group and the pure OSAHS group. The level of25(OH)D3in the hypertension combined OSAHS group was lower than the purehypertension group,and the difference is significant(P<0.05).3．The AHI and body mass index(BMI) of patients in severe OSAHS group weresignificantly higher than that of in pure hypertension, mild、moderate OSAHS group（P＜0.01);The levels of25(OH)D3and saturation of minimum oxygen from skin ofpatients in severe OSAHS group were obviously lower than that of in purehypertension, mild、moderate OSAHS group(P＜0.01); Fasting blood glucose inpatients with severe OSAHS group was higher than pure hypertension, and thedifference was statistically significant (P <0.05).4． Pearson correlation analysis showed that25(OH) D3was negativelycorrelated with systolic blood pressure, diastolic blood pressure, LDL-C,BMI andAHI (P <0.05), as well as were positively correlated with MSPO2(P <0.01).5. Multiple linear regression analysis showed that the level of serum25(OH)D3in hypertensive patients with OSAHS was positive correlation with saturation ofminimum oxygen,while it also negatively associated with AHI.Conclusion1. Hypertension combined with obstructive sleep apnea syndrome in patients with serum vitamin D levels reduced further, and the lower level may be associatedwith the severity of obstructive sleep apnea.2. Serum vitamin D level was negatively correlated with AHI, and waspositively correlated with MSPO2. The possible reason was repeated hypoxiacondition affecting the absorption and metabolism of vitamin D.3. Obstructive sleep apnea syndrome in patients with low levels of vitamin D maybe one of the pathophysiological mechanisms which OSAHS patients causehypertension.