The effects of improved metabolic risk factors on bone turnover markers after 12 weeks of simvastatin treatment with or without exercise

Abstract

ObjectiveEmerging evidence supports an association between metabolic risk factors and bone turnover. Statins and exercise independently improve metabolic risk factors; however whether improvements in metabolic risk factor affects bone turnover is unknown. The purpose of the present study was to: 1) evaluate the relationship between metabolic risk factors and bone turnover; and 2) determine if improvements in metabolic risk factors after 12weeks of statin treatment, exercise or the combination affect bone turnover. MethodsFifty participants with ≥2 metabolic syndrome defining characteristics were randomly assigned to one of three groups: statin (STAT: simvastatin, 40mg/day), exercise (EX: brisk walking and/or slow jogging, 45minutes/day, 5days/week), or the combination (STAT+EX). Body composition and whole body bone mineral density were measured with dual energy X-ray absorptiometry. Serum markers of bone formation (bone specific alkaline phosphatase, BAP; osteocalcin, OC), resorption (C-terminal peptide of type I collagen, CTX) and metabolic risk factors were determined. Two-factor (time, group) repeated-measures ANCOVA was used to examine changes of metabolic risk factors and bone turnover. General linear models were used to determine the effect of pre-treatment metabolic risk factors on post-treatment bone turnover marker outcomes. ResultsParticipants with ≥4 metabolic syndrome defining characteristics had lower pre-treatment OC than those with 3 or fewer. OC was negatively correlated with glucose, and CTX was positively correlated with cholesterol. STAT or STAT+EX lowered total and LDL cholesterol. The OC to CTX ratio decreased in all groups with no other significant changes in bone turnover. Higher pre-treatment insulin or body fat predicted a greater CTX reduction and a greater BAP/CTX increase. ConclusionMetabolic risk factors were negatively associated with bone turnover markers. Short-term statin treatment with or without exercise lowered cholesterol and all treatments had a small effect on bone turnover.