Study On The Relationship Between Vitamin D And Its Receptor Gene Polymorphism And Senile Muscle Attenuation Syndrome

ObjectivesAs Chinese society entered the aging society, age-related diseases in the elderly increased significantly, which has become a major health problem to reduced the quality of life in the elderly. Human skeletal muscle mass and function is going to be declining with aging,it will become sarcopenia when the skeletal muscle mass, muscle strength or function decays to a certain extent.A few studies found that vitamin D and the polymorphism of Vitamin D Receptor (VDR) gene were associated with sarcopenia in the elderly. This paper is to analyze the association between the serum vitamin D and sarcopenia and discuss the correlation between the polymorphism of vitamin D receptor genetype and sarcopenia in the elderly.Methods1 Cross-Sectional StudyTwo community hospitals in Shijingshan District, Beijing were chosen and the senior adults over 60 years without serious disease or being free of joint disease with restricted activity were recruited into the study at the screening stage. Information on demography, lifestyle and dietary were assessed with a food frequency questionnaire. Grip strength, 4-meter regular walking speed, indicators of body examination and body composition were also measured. Physical measurements include height, weight, arm circumference, calf circumference, waist measurement, and other dimensions. Muscle mass was measured (using Inbody720 body composition analyzer) and function (grip strength,4-meter regular walking speed) were measured. Laboratory indicators are including serum vitamin D levels; parathyroid hormone (PTH) levels; genomic DNA of blood cells, VDR genotype and the biochemical indicators (including total cholesterol, triglycerides, glucose, Creatinine, albumin).2 Case-Control StudyAccording to the diagnostic procedure of the sarcopenia (see Figure 2-1), all the participants in the screening stage who has the sarcopenia were selected to the case group. We can select control group by matching the sex and age (within±2 years); other non-research factors to ensure consistence as much as possible.3 Intervention ExperimentWe can suffer from the participants who have sarcopenia and vitamin D deficiency (serum 25 (OH) D<20 ng/ml) to be intervention group, matching the age. sex and other non-research factors as control group. Two groups were divided into two sub-groups by vitamin D receptor genotype(The selected participants measure muscle mass by dual energy X-ray absorption spectroscopy (DXA), dietary survey by combining 3 days 24 hours and weighing method).Vitamin D capsules (800IU/d) supplement to the intervention group, vitamin E capsules (100mg/d) supplement to control group.4 Statistical analysis In this study; logging data twice by Epidata3.0 and the database was established by it. SAS package version 9.4 (SAS Institute Inc, Cary, NC) was used for analyses. Covariance analysis with General Linear Model (GLM) was used to calculate the mean and 95% CI of gait speed, grip strength SMM, ASM and RSMI by vitamin D quartile after adjustment for covariates such as sex, age, sun explore and physical activity. The prevalence of sarcopenia and its components were described as prevalence and 95% CI. Wald chi-square test was used to compare the difference of the prevalence among vitamin D quartiles. Non-condition Logistical Regression Model was employed to explore the association of vitamin D with muscle mass and function. Four models were explored with low SMM, low grip, low gait speed and sarcopenia as a dependent variable, respectively. No other variable except vitamin D level was included as independent variable in Unadjusted Model. We drew 11 potential confounders (gender, age, occupation, sun exposure, physical activities, education, body fat percentage, smoke, alcohol drinking, dietary protein and energy intake) as independent variables in Model I. On the basis of Model Ⅰ, low grip strength, low gait speed and Low SMM, were additionally adjusted for each other in Model Ⅱ. P values of less than 0.05 were considered statistically significant.Results1 Cross-Sectional StudyA total of 894 participants were genotyped for VDR-rs 1544410 (Bsml) (allele frequencies Bb/AG=11.4%,bb/GG=88.6%,BB/AA=0). For VDR-rs2228570 (Fokl) (allele frequencies FF/CC=32.8%,Ff/CT=45.1%,ff/TT=22.1%) and these two genotypes have no significant differences in gender(P>0.05).Female bb genotype grip was 23.3kg (20.1kg-26.3kg), which was greater than the Bb genotype female grip 21.5kg (19.7kg-24.3kg),the difference was statistically significant (P<0.05).In spite of number, the low grip ratio and low speed ratio of bb genotype was lower than that Bb genotype in female. RSMI of FF、 Ff、ff genotype in male was 7.6kg/m2,7.6kg/m2、 7.8kg/m2,respectively and the difference was significant(P<0.05).The prevalence of sarcopenia in male of FF、Ff、ff was 17.6%、23.0%、8.5%, respective and the difference was significant(P<0.05).2 Case-Control StudyCase-control study matching sex and age was found that the general factors of sarcopenia was exercise, BMI, education level and eating in the outdoor(at least once a week).Multivariate logistic regression analysis shows that dietary factors about sarcopenia in elderly were fish/marine products and other animal foods, the risk of sarcopenia of fish and shrimp intake...