Adipocytokine and ghrelin levels in relation to bone mineral density in physically active older women: longitudinal associations

Abstract

We investigated the relationship between the decrease in bone mineral mass (BMC) and bone mineral density (BMD) values with baseline adipocytokine and ghrelin concentrations in physically active postmenopausal women. Leptin, adiponectin, ghrelin, BMC, BMD and different body composition values were measured in 35 women (age: 69.7+/-6.0 years) before and after a 12-month prospective study period. Significant (P<0.05) decreases in fat-free mass (FFM) (by 2.56%) and BMC (by 1.63%) and increases in adiponectin (by 14.8%) were seen in older females as a result of the study period. The independent variables that were associated with decreases in total BMC were baseline fat mass (FM) and adiponectin explaining 30.6% (R(2)x100) of the total variance. In another model, baseline FFM and leptin were the independent variables that explained 20.6% (P<0.05) of the total variance in the decreases in total BMD value. The variables that were associated with decreases in femoral neck BMD were FM and leptin (R(2)=0.102; P<0.05), while the independent variables were baseline trunk fat:leg fat ratio and adiponectin in the model with decreases in lumbar spine BMD as the dependent variable, and accounted for 13.1% (P<0.05) of the decreases in BMD variance. Initial adiponectin concentration together with specific body composition characteristics predicted loss in BMC and lumbar spine BMD values, while initial leptin concentration together with specific body composition parameters determined the loss in total and femoral neck BMD values in physically active older women.