Effect of low-dose prednisone (with calcium and calcitriol supplementation) on calcium and bone metabolism in healthy volunteers

The administration of moderate to high doses of corticosteroids isassociated with bone loss. This probably results from the uncoupling ofbone formation (decreased) and bone resorption (unchanged or increased). Weexamined the effect of low-dose (10 mg/day) prednisone (LDP) and thepossible mitigating effects of calcium and 1.25 (OH)2 vitamin D(calcitriol) on calcium and bone metabolism in eight healthy, young malevolunteers. The study consisted of four observation periods: in the firstperiod, LDP was prescribed during 1 week; in the second, third and fourthperiods, calcium (500 mg/day), calcitriol (0.5 micrograms b.i.d.) andcalcium in combination with calcitriol, respectively, were added to LDP.Bone formation was measured by means of serum osteocalcin, carboxy-terminalpropeptide of type 1 procollagen (P1CP) and alkaline phosphatase, boneresorption by means of urinary excretion of calcium, hydroxyproline, (freeand total) pyridinoline, (free and total) deoxypyridinoline and serumcarboxy-terminal cross- linked telopeptide of type 1 collagen (1CTP).Dietary calcium and sodium intake were maintained at a stable level duringthe entire study period. Treatment with LDP led to a decrease inosteocalcin, P1CP and alkaline phosphatase (all P < 0.01). Urinaryexcretion of pyridinolines, hydroxyproline and serum 1CTP did not increase,but remained unchanged or slightly reduced (P < 0.05), depending on thetime of measurement and the marker of bone resorption. Parathyroid hormone(PTH) (insignificantly) increased during LDP (+19%) and LDP plus calcium(+14%), but decreased during supplementation with calcitriol (-16%) andcalcium/calcitriol (-44%; P < 0.01). Urinary excretion of calciumincreased during treatment with LDP and calcitriol (P < 0.05) andcalcium/calcitriol (P < 0.05). It is concluded that LDP has a negativeeffect on bone metabolism, since bone formation decreased while boneresorption remained unchanged or decreased slightly. The increase in PTHduring LDP could be prevented by calcitriol combined with calciumsupplementation.