| Objective: Vitamin D is one of the essential nutrients for human growthand development. In recent years, the incidence of vitamin D deficiency is inthe escalating trend and the population of hypovitaminosis is becoming muchyounger. Cardiovascular disease is a threat to human health, especially to theelderly population. There are a great many risk factors that can causecardiovascular disease, including uncontrolled and controlled factors. Theuncontrolled variables contain sex, gender, family history and so on. Whilerisk factors such as blood pressure, blood glucose and serum lipid levelsconsist the controlled variables. Arteriosclerosis, which is one of the diseasethat affected by many risk factors, can lead to cardiovascular events.However, carotid artery can be a reflection of arteriosclerosis, and carotidintima-media thickness (CIMT) is an important symbol that can evaluate thefunction of vascular endothelial cells. So the severity of cardiovascular diseasemight be assessed by measurements of the CIMT. It is well known to all thatvitamin D has an important role in the metabolism of calcium and phosphorus.Besides, the part of vitamin D plays in the non-skeletal system, especially inthe development of cardiovascular disease, metabolic syndrome andimmunological diseases attracts people’s much more attention recently. In thisstudy, we collected696eligible middle-aged and elderly physical examineeswho visited the Health Examination Center of Hebei Province GeneralHospital for annual physical examination from Nov2012and Feb2013. Weanalyzed the correlation between CIMT and the serum25(OH) Dconcentrations.Methods:696physical examinees were selected to measure their CIMTwith ultrasound. Peripheral venous blood samples were collected from allparticipants after an8-12-hour overnight fasting, which were collected in tubes and centrifuged at4°C. The serum was stored at–80°C until analysis.Serum25(OH) D levels and inflammatory factors were measured. Besides, wedetected the glucose, lipids, hepatic and renal function in plasma by automaticbiochemical analyzer, and analyzed the data with SPSS (16.0) software.Results:1The association of the baseline characteristics and CIMTAccording to the level of CIMT, the participants were divided intonormal CIMT group (≤0.9mm) and abnormal CIMT group (>0.9mm). Weobserved the differences of age, sex,25(OH) D levels, glucose, lipid levels,hepatic and kidney function between the two groups by Student t test,nonparametric test or chi-square test. The results indicate that the level ofCIMT of the two groups are0.75±0.09mm and1.25±0.19mm (P<0.01),respectively. The level of serum25(OH) D in the abnormal group is higherthan that in the normal group [25.33(14.78,39.05) and17.15(9.40,27.41),P<0.01]. Similarly, the age of the subjects in the abnormal group is older thanthose in the normal group (P<0.01). We detected the differences of WC, SBP,HDL-C, LDL-C, FBG, HbA1c, Cr, BUN and inflammatory factors such asIL-6, TNF-α and CRP between the two groups. HDL-C levels in the normalgroup is mild higher than that in the abnormal group (P=0.030). While thelevel of WC, SBP, LDL-C, FBG, HbA1c, Cr, BUN, IL-6, TNF-α and CRP inthe abnormal group were higher than those in the normal group (P<0.01). Weanalyzed the differences of smoking, alcoholic drinking, hypertension, familyhistory of diabetes mellitus, fatty liver and plaque in the two groups bychi-square test. The results suggested that the proportion of the subjects withplaque in the abnormal group (44.6%) was higher than that in the normalgroup (19.9%)(P<0.01). However, there was no difference of smoking,alcoholic drinking, hypertension, family history of diabetes mellitus and fattyliver between the two groups.2The association of serum25(OH)D and related metabolic factorsThe median concentration of serum25(OH) D was26.45nmol/l(range:13.01-35.63nmol/L）in our study participants. The percentages ofvitamin D deficiency and insufficiency were89.7and8.8%, respectively. We divided all the participants into four groups across25(OH) D quartiles anddetected the correlation between serum25(OH) D level and related metabolicfactors by Spearman’s correlation coefficient. The results suggested that25(OH) D was negatively associated with CIMT, IL-6and CRP, which had nolinear correlation with age, glucose, hepatic and other related metabolicfactors (P>0.05).3The serum25(OH) D concentrations according to the age groupWe divided the subjects into four groups according to each10-year oldincreasing of age. The differences between groups were compared usingKruscal-Wallis H and Mann-Whitney U analysis. The results showed that highconcentrations of25(OH)D were especially observed in the subjects of group60-69years old with a median of26.37nmol/L, but only had difference withgroup40-49years old (P=0.005).4The sex-specific CIMT according to the serum25(OH)D levelsWe observed the differences of CIMT between groups usingKruscal-Wallis H and Mann-Whitney U analysis. The CIMT differencesbetween males and females in the same group were analyzed bynonparametric test. The results suggested that CIMT was likely to be greaterin males than females in the same25(OH) D quartiles, but there is nostatistically significance (P>0.05). The CIMT in Q4was lower than that in Q1and Q2of both males and females (P<0.01).5The correlation of CIMT and related metabolic factorsCIMT was treated as an independent factor. We detected the correlationof CIMT and serum25(OH) D levels, age, sex, gender, WC, BMI, bloodpressure, smoking, alcoholic drinking, lipids, glucose, HOMA-IR andinflammatory factors by multivariable logistic regression. The results showedthat there was a negative association between CIMT and25(OH) D levels, anda positive association with age, LDL-C, smoking status, HOMA-IR, IL-6,CRP and plaque. Therefore, serum25(OH) D levels is a protective factor ofarteriosclerosis.6The association of serum25(OH) D and CIMT may be partly mediated byinflammatory factors We observed the possible function of inflammatory factors in the processof CIMT change by logistic regression. Results showed that serum25(OH) Dconcentrations were lower in subjects with abnormal CIMT than those withnormal CIMT (median value:17.15vs.25.33nmol/L, P<0.01). The risk ofhaving abnormal CIMT increased progressively across the highest to thelowest quartiles of25(OH) D with the ORs of1.96(95%CI1.19-3.24),2.55(95%CI1.57-4.14) and4.89(95%CI2.93-8.18) after adjusting for age(Model1). Further controls of plaque (yes/no), HOMA-IR (≤2.02/＞2.02),LDL-C, and smoking (current yes or no)(Model2), the ORs were1.57(95%CI0.91,2.70),2.21(95%CI1.31,3.74) and4.08(95%CI2.35,7.09).However, after additional adjustment for IL-6and CRP (Model3), the ORs ofCIMT abnormal risk declined.Conclusions:1The serum of25(OH) D was negatively associated with CIMT amongMiddle-Aged and Elderly Chinese urban physical examinees, and25(OH) Ddeficiency and insufficiency was a risk factor of arteriosclerosis disease.2The association of serum25(OH) D and CIMT may be partly mediatedby inflammatory factors (CRP and IL-6). |
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