BIOTIN STATUS AND ITS CORRELATION WITH OTHER BIOCHEMICAL PARAMETERS IN THE ELDERLY PEOPLE OF JAPAN

Objective: Biotin plays important roles in carbohydrate and lipid meta bolism as well as in the decarboxylation of amino acids. In this study , to determine the biotin status in elderly people, we determined the levels of biotin and other biochemical variables in their serum. Metho ds: Blood was collected from 685 elderly people aged 65 years and over (284 men and 401 women) and from 2,004 reference people Biotin levels in the serum were microbiologically quantified by the agar plate meth od and other biochemical variables were recorded using the autoanalyze r. Results: The serum biotin level in elderly people was 10.2 +/- 7.20 pmol/ml (2.5 +/- 1.76 ng/ml), the distribution of which was skewed to the right compared to the reference group (9.4 +/- 1.43 pmol/ml) (2.3 +/- 0.35 ng/ml). How ever, serum biotin levels did not change with ag e in the elderly people and no sex-related differences were detected O n the basis of the correlation coefficients among the biochemical vari ables in the serum, biotin levels were correlated positively with the total cholesterol level. A negative correlation was found between the biotin level and the serum albumin, triiodothyronine, phosphate, and c alcium levels. On the other hand, 5.8% of the elderly people had bioti nyl IgG in their serum, which did not differ from the percentage in th e reference group (4.1%). However, in the elderly people the level af biotinyl IgG positivity; was significantly lower in women than in men (4.1% vp 8.1%). in the biotinyl IgG positive elderly, the levels of pa rathyroid hormone and total cholesterol were lower, whereas the uric a cid level was higher compared to the biotinyl IgG negative elderly. Co nclusions: Although serum biotin levels are not affected by aging, the serum biotin levels of elderly people vary greatly.