Following the alkaline denaturation (to discharge folate from the endogenous joining necessary protein) and you will stabilizing (to end oxidation), a keen aliquot of your own handled attempt is moved to the a good streptavidin-painted better. Adopting the a competitive binding effect (folate on gel test competes with HRP-labeled folate getting a restricted number of joining sites towards a biotinylated FBP), brand new FBP complexes is actually captured by the streptavidin to your wells. Unbound conjugates was removed by the laundry.
Brand new sure HRP conjugates having 25-OH nutritional D, B12 and you may folate was indeed measured because of the good luminescent impulse (18). Reagent that has luminogenic substrates (luminol derivative and you will peracid salt) and an electron transfer representative (substituted acetanilide) are added to this new wells. Oxidation of one’s luminol by-product was catalyzed by the HRP for the the latest likely conjugates, ergo generating white. The newest power and duration of white emission had been increased from the electron transfer broker, while the light signals was indeed understand because of the program. The amount of HRP conjugate likely are ultimately proportional with the concentration of twenty five-OH vitamin D, vitamin B12 and you may folate found in the decide to try, correspondingly.
For vitamin D, ?30 ng/ml was considered as normal, <30 ng/ml was classified as low vitamin D and <20 ng/ml as vitamin D deficiency. For vitamin B12, ?200 pg/ml was considered as normal and <200 pg/ml as deficiency. For folic acid, ?3 ng/ml was considered as normal and <3 ng/ml as deficiency.
Statistical Analysis
Statistical analysis was done using JASP open-source software, version 0.14.1. Primary quality assessment of range and consistency of the variables was done to check appropriateness of units and deviation from the population mean, to detect outliers. Age (45–54, 55–64, 65–74, ?75 years) and gender distributions were tabulated. Frequency distributions of vitamin D, vitamin B12 and folic acid levels in the population were plotted. Mean levels of the above parameters were calculated. “t” test was performed to check for significant differences between mean values of males and females – both overall and in each of the age groups. Ain B12 and folic acid levels between all age groups and also, between age groups among females and males separately. Percentage of subjects having deficiency of the studied micronutrients was calculated according to gender as well as among different age-groups. Chi-squared test was done to check for any significant differences, gender-wise and age-group-wise. P-value of < 0.05 was considered as significant.
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Gender distribution of the study population was 47.1% (n = 776) males and 52.9% females (n = 872). Mean age of the population was 58 ± 10.2 years, with males having a higher mean age than females (59.5 ± 10.4 vs. 56.6 ± 9.8 years). Out of the 1,648 subjects in this analytical sample, vitamin D levels were available for 1,546 subjects, vitamin B12 levels were available for 1,639 subjects and folic acid levels were available for 1,640 subjects. Frequency distribution of vitamin D, vitamin B12 and folic acid levels are shown in Figure 1. Mean levels of vitamin D, B12 and folic acid were 23.4 ± 10.6 ng/ml, 277.4 ± 194.4 pg/ml and 6 ± 3.5 ng/ml, respectively. Age and gender-stratified means with standard deviations for the above three parameters are represented in Table 1. Significant gender difference was observed in mean values for vitamin D (males > females; p < 0.001) and folic acid (females > males; p < 0.001) but not for vitamin B12. Significant difference was also seen in mean vitamin D among levels between different age groups – overall (f = 3.73, p = 0.011) as well as among males (f = 7.74, p < 0.001) but not among females (f = 2.01, p = 0.11). Tukey post-hoc test showed that there was significant difference in 55–64 years age group as compared to ?75 years age group. Among males, this difference was significant in 45–54 years age group as compared to ?75 years age group. Similarly, significant difference was also seen in 55–65 years age group as compared with 65–74 years and ?75 years age groups among males. Significant difference was seen in vitamin B12 means between different age groups – overall (f = 4.99, p = 0.002) as well as among females (f = 5.68, p < 0.001) but not among males (f = 1.01, p = 0.38). On post-hoc analysis, significant difference was seen when the mean of 45–54 years age group was compared to 65–74 years and ?75 years age groups. A similar difference was also observed between the same age groups among females. There was no statistically significant difference for the folate levels among different age groups, neither in the overall age groups nor in the gender-stratified age-groups.