Association Between Vitamin D Levels And Prevalence Of Fatty Liver Disease In Middle-Aged And Elderly Population In Yaohai District Of Hefei City

Objective The prevalence of Fatty Liver Disease（FLD）is increasing in the middle-aged and elderly population in China.Vitamin D deficiency and deficiency are also a serious problem worldwide.However,the relationship between vitamin D nutritional status and FLD in older adults is not well established.In this study,middle-aged and elderly people aged 40～69 years in a community hospital in Hefei were selected as the research objects.A cross-sectional survey was adopted to understand the vitamin D nutritional status of middle-aged and elderly people in this area.Based on the assessment of the distribution characteristics of FLD and vitamin D nutritional status,the association between vitamin D nutritional status and FLD in middle-aged and elderly people was analyzed,so as to provide a new direction for reducing the prevalence of FLD in middle-aged and elderly people.Methods From October 2019 to February 2020,a cross-sectional survey was carried out on the population undergoing physical examination in a community hospital in Hefei,and 645 people were finally included in the study.Self-designed questionnaires were used and face-to-face surveys were conducted by trained and qualified professional investigators.The contents of the survey mainly include:demographic data,anthropometric data,physiological and biochemical indicators and other related information;B-mode ultrasonography was used to diagnose FLD and its severity.Serum25（OH）D₃levels were determined by electrochemiluminescence.Median（P25,P75）was used to represent continuous variables that did not follow normal distribution,and mean±standard deviation was used to represent other continuous variables.All classification variables,expressed as a percentage（%）.The distribution of continuous and categorical variables in FLD and different vitamin D nutritional status was compared by one-way ANOVA,nonparametric test and Chi-square test.Logistic regression was established to analyze the relationship between vitamin D nutritional status and fatty liver disease,and stratified analysis was performed by sex and age.Kendall’s tau-b grade correlation coefficient was used to describe the correlation between vitamin D nutritional status and the severity of fatty liver disease,and stratified analysis was conducted for gender and age.Results A total of 645 people were included in this study,including 418 males（64.81%）and 227 females（35.19%）.407（63.10%）are aged 40～49,and 238（36.90%）are aged50～69.There were 331 FLD patients,accounting for 51.32%of the total subjects.In general demographics,the prevalence of FLD was statistically significant in gender,age,smoking,alcohol consumption,BMI,diabetes,hypertension and dyslipidemia（P<0.05）.In terms of biochemical indicators,the prevalence of FLD was significantly different in the distribution of ALT,AST,HDL-C,TG,GLU and UA（P<0.05）.In this study,351people（54.42%）were vitamin D deficiency.The number of vitamin D insufficiency was 264（40.93%）.Only 30（4.65%）had adequate vitamin D.Univariate Logistic regression analysis showed that compared with the middle-age and elderly with vitamin D deficiency,vitamin D insufficiency had a lower risk of FLD,but was not statistically significant（OR=0.806,95%CI:0.586-1.110,P=0.187）,the risk of FLD was reduced in vitamin D sufficiency（OR=0.249,95%CI:0.104-0.596,P=0.002）.After adjusting for demographic variables（sex,age,smoking,alcohol consumption,physical exercise,BMI,diabetes,hypertension,dyslipidemia）and biochemical indicators（ALT,AST）,the decreased risk of FLD in vitamin D insufficiency was merely shows a downward trend（OR=0.801,95%CI:0.559-1.149,P=0.228）,the risk of FLD was reduced in vitamin D sufficiency group（OR=0.221,95%CI:0.089-0.550,P<0.001）.Stratified analysis of gender and age,univariate logistic regression analysis of male showed that compared with vitamin deficiency group,vitamin D insufficiency group had a lower risk of FLD with no statistical significance（OR=0.997,95%CI:0.659-1.508,P>0.05）,and the risk of FLD in middle-aged and elderly people with adequate vitamin D was 0.325 times of it in the middle-aged and elderly people with vitamin D deficiency（OR=0.325,95%CI:0.123-0.589,P<0.05）.After adjusting for other demographic variables（sex,age,smoking,alcohol consumption,physical exercise,diabetes,hypertension,dyslipidemia）and biochemical indicators（ALT,AST）,risk of FLD in men with vitamin D insufficiency in middle-aged and elderly people merely shows a downward trend（OR=0.928,95%CI:0.594-1.452,P>0.05）,the risk of FLD was decreased with vitamin D sufficiency,and the risk was 0.207 times of the risk of vitamin D deficiency group（OR=0.207,95%CI:0.070-0.611,P<0.05）.Vitamin D nutritional status was not significantly associated with FLD in women.In the age of 40～49 years old group,univariate Logistic regression analysis showed that the risk of FLD decreased in the vitamin D insufficiency group,but there was no statistical association（OR=0.913,95%CI:0.611-1.365,P>0.05）and vitamin D sufficiency（OR=0.364,95%CI:0.114-0.803,P<0.05）was associated with reduced risk of FLD.After adjusting for other demographic variables（sex,age,smoking,alcohol consumption,physical exercise,diabetes,hypertension,dyslipidemia）and biochemical indicators（ALT,AST）,the risk of FLD decreased in the elderly with vitamin D deficiency,but there was no statistical significance（OR=0.938,95%CI:0.592-1.485,P>0.05）,and vitamin D sufficiency（OR=0.214,95%CI:0.057-0.801,P<0.05）still reduced the risk of FLD.In age of50～69 years old group,univariate and multivariate logistic regression analysis showed that vitamin D deficiency was not significantly associated with FLD.Before adjustment,vitamin D sufficiency was associated with a reduced risk of FLD（OR=0.227,95%CI:0.074-0.698,P<0.05）;After adjustment for relevant variables,vitamin D sufficiency remained significantly associated with a reduced risk of FLD in middle-aged and elderly people（OR=0.181,95%CI:0.047-0.700,P<0.05）.Kendall’s tau-b correlation analysis showed that vitamin D nutritional status was negatively correlated with the degree of FLD in the population,but there was no statistical significance（r=-0.079,P=0.143）.Stratified analysis by gender showed that vitamin D nutritional status was negatively correlated with the degree of FLD in both males and females,but there was no significant statistical correlation（P>0.05）.Stratified analysis by age showed that there was no significant correlation between vitamin D nutritional status and the degree of FLD in subjects aged 40～49（P=0.982）.However,there was a significant negative correlation between vitamin D nutritional status and the degree of FLD in the aged50～69 years（r=-0.177,P=0.029）.Conclusions This study found that vitamin D nutritional status was significantly correlated with FLD,and there was a significant negative correlation between vitamin D nutritional status and the degree of FLD in the middle-aged and elderly in this area.This study provides theoretical basis for studies on the correlation between vitamin D nutritional status and FLD in middle-aged and elderly people,and the results need to be verified by more studies in the future.