After the administration of calcium plus vitamin D supplements , we observed a significant reduction in fasting plasma glucose ( -@ @ vs +@ @ mmol/l , p < @ ) , serum insulin levels ( -@ @ vs +@ @ pmol/l , p = @ ) and HOMA-IR ( -@ @ vs +@ @ , p = @ ) and a significant increase in QUICKI ( +@ @ vs -@ @ , p = @ ) compared with placebo .