Effect of three different doses of vitamin D (ergocalciferol)on muscle function and strenght in women >65 years: a preliminary study

MASTAGLIA SR; SEIJO M; MUZIO DM; SOMOZA J; OLIVERI B

Montreal

Congreso; 30th Meeting ASBMR; 2008

ASBMR

Vitamin D insufficiency is frequently observed in subjects aged > 65 years. Serum levels of 25-hydroxyvitamin D (25OHD)>20ng/ml would seem optimum for adequate muscle function and strength. In a previous study (JBMR 22: Suppl.1;2007) we evaluated 40 postmenopausal women; 20 had mean 25OHD levels (X+/-DS) at 31.8+/-6 ng/ml and exhibited improved muscle function compared to those with average 25OHD levels at 12.9¡À3ng/ml (7.3+/-1 vs. 6.7+/-2 scores; p<0.02). The aim of this study was to evaluate the effect of 3 different doses of vitamin D2 administered for 6 months, on muscle function and strength in the group of women with levels of 25OHD<20ng/ml. Twenty postmenopausal women from Buenos Aires (34ºSª), mean age (X+/-DS) 70.5+/-4 were randomly assigned to one of the following three groups (G) to receive: 800IU/day G 1 (n=6); 5.000IU/day G2 (n=6); and 10.000IU/day G3 (n=8). All the subjects received calcim carbonate supplementation (500mg/day). Serum calcium, phosphate, 25OHD, bone alkaline phosphatase (BAP), and crosslaps (CTX) were determined, as well as 24-hours urine calciuria/creatininuria. Muscle function was assessed in terms of gait speed, balance, and stand-and-sit-test. Muscle strength of lower limbs was evaluated using a manual dynamometer. All determinations were performed at baseline and at 6 months. G2 and G3 were analyzed as a whole. Average baseline 25OHD of the whole group was 13 ng/ml. At 6 months, 25OHD levels reached 18.4+/-2.5ng/ml in G1 and 29.+/-11.4ng/ml in G2 +G3; G2 and G3 showed an improvement in their gait speed test (baseline:3.2+/-0.9 vs. 6 months: 3.6+/-0.9 score; p<0.05) at 6 months. No significant changes in muscle strength were observed in any of the groups at the end of the study. Serum and urinary levels of calcium remained within reference values; no significant changes in BAP or CTX were observed. The dose of vitamin D supplementation for subjects in the age group at risk of suffering falls and osteoporotic fractures should be higher than the currently recommended dose.