Analysis Of Serum Vitamin D Level And Related Factors In Community Elderly Population

Objective:1)To describe the level of serum vitamin D,the prevalence of vitamin D insufficiency and deficiency and their distribution in community elderly in Tianjin.2)To explore the relationship between serum vitamin D levels and physical examination indexes and laboratory test indexes in the elderly,and to analyze the related factors of vitamin D insufficiency and deficiency.3)To discover the relationship between serum vitamin D levels and cardio-cerebrovascular disease.Methods:Two community health service centers were randomly selected from Tianjin urban area by random cluster sampling.From April to May 2017,all the elderly over 60 years old who met the selection criteria in the above two community health service centers were selected for this study.Questionnaires,physical examinations and laboratory tests of blood lipids were completed with the assistance of community doctors.Serum vitamin D level（25（OH）D₃）was determined by high performance liquid chromatography（HPLC）in the laboratory.EpiData software was used for input and SPSS16.0 software package was used for data analysis.For quantitative data,mean and standard deviation or median and quartile spacing were used for statistical description.The differences between groups were compared by t test,variance analysis,covariance analysis or non-parametric test.Qualitative data were described by the number of cases（constituent ratio）,and chi-square test was used to compare the differences between groups.Linear regression was used to explore the relationship between vitamin D level and physical examination index and laboratory test index.Logistic regression analysis was used to explore the related factors of vitamin D deficiency and deficiency,and the relationship between vitamin D level and cardio-cerebrovascular disease.Result:1)A total of 988 subjects from community health service centers who met the selection criteria were collected.22 of them were excluded from the study,and 966people were included in the data analysis.The effective rate was 97.8%.There were394 males（40.8%）and 572 females（59.2%）,with an average age of 69.27±6.78years.2)Serum 25（OH）D₃ level showed skewed distribution.The median（quartile spacing）was 26.84（19.38,35.66）ng/ml.After logarithmic transformation,it obeyed normal distribution.The average level of Lg25（OH）D₃ was 1.42±0.19.The overall prevalence of vitamin D insufficiency and vitamin D deficiency among the elderly in Tianjin was59.8%,of which 315 were vitamin D insufficient,with the prevalence of 32.6%,263were vitamin D deficient,with the prevalence of 27.2%.3)Comparing the serum 25（OH）D₃ level and the prevalence of vitamin D insufficiency and deficiency among different sex,age,education level,weight status,smoking,drinking and current medical history,no significant difference was found.4)Multiple linear regression showed that serum 25（OH）D₃ level was negatively correlated with male,triglyceride and high density lipoprotein cholesterol（HDL-C）,and the regression coefficients were-0.105（P=0.019）,-0.127（P=0.007）and-0.126（P=0.043）,respectively.And serum 25（OH）D₃ level was positively correlated with height and total cholesterol,with the regression coefficients 0.083（P=0.014）and0.375（P=0.010）,respectively.According to sex stratification analysis,serum25（OH）D₃ level was positively correlated with total cholesterol in elderly men with a regression coefficient of 0.198（P=0.003）,and serum 25（OH）D₃ level was negatively correlated with triglyceride level and high density lipoprotein cholesterol.The regression coefficients were-0.155（P=0.020）and-0.137（P=0.044）,respectively.In elderly women,serum 25（OH）D₃ level was negatively correlated with high density lipoprotein cholesterol.The regression coefficient was-0.107（P=0.018）.5)Multivariate logistic regression analysis showed that systolic blood pressure,waist circumference and BMI were the related factors of vitamin D insufficiency and deficiency in the elderly.The OR value and 95%CI were 1.25（1.035-1.513）,0.78（0.61-0.98）and 1.29（1.02-1.63）,respectively.According to sex stratified analysis,the main related factors of vitamin D insufficiency and deficiency were waist circumference and total cholesterol.The OR value and 95%CI were 0.67（0.45-1.00）and 0.73（0.55-0.97）,respectively.Systolic blood pressure（SBP）was the main risk factor for vitamin D insufficiency and deficiency in women.The OR value and 95%CI were 1.23（1.02-1.49）.6)There was no statistical correlation between serum vitamin D level and cardio-cerebrovascular disease in the general population by univariate and multivariate logistic regression analysis.The level of vitamin D was related to coronary heart disease in the elderly male population.The OR and 95%CI were 1.05（1.02-1.08）.Conclusion:The average level of serum 25（OH）D₃ in community elderly population in Tianjin was low,vitamin D insufficiency and vitamin D deficiency were common,and the prevalence of vitamin D insufficiency and deficiency between males and females was not statistically different.Serum 25（OH）D₃ level was positively correlated with total cholesterol and negatively correlated with triglyceride level and high density lipoprotein in elderly men.Serum 25（OH）D₃ level was negatively correlated with systolic blood pressure in elderly women.Male vitamin D deficiency and deficiency were mainly negatively related to waist circumference and total cholesterol,while female vitamin D deficiency and deficiency were mainly positively related to systolic blood pressure.Vitamin D level was correlated with male coronary heart disease.No statistical correlation was found between vitamin D level and hypertension and stroke.