Sclerostin and Dickkopf-1 Characteristics According to Age and Physical Activity Levels in Premenopausal Women.

Abstract

We aimed to compare serum concentrations of sclerostin and DKK-1 in young (20-30 yrs, n=25) and middle-aged (35-45 yrs, n=25) premenopausal women and based on physical activity (PA) status. PA status was assessed by the International Physical Activity Questionnaire (low-moderate (/= 3000 MET-min/week). Serum sclerostin and DKK-1 levels were measured in fasting morning blood samples by ELISA. Areal bone mineral density (aBMD) was measured by DXA, and non-dominant tibia bone characteristics were assessed by pQCT. After adjusting for total body aBMD, middle-aged women had significantly (p < 0.001) higher (0.54 +/- 0.01 ng/mL) serum sclerostin than young women (0.41 +/- 0.01 ng/mL), and sclerostin was positively correlated with age (rs=0.065, p </= 0.001) and total PA score (rs=0.33, p=0.021). Young women had higher left trochanter aBMD (p=0.036) than middle-aged women and aBMD variables were higher (all p </= 0.043) in the high active group. Middle-aged women had higher 38% cortical vBMD than young women (p=0.021), otherwise young women had higher values for pQCT variables (all p </= 0.036). Sclerostin showed significant correlations (r=0.32 to 0.58, all p </= 0.026) with spine aBMD for the entire cohort and for each age group. Middle-aged women had significant correlations between sclerostin and hip aBMD sites (r=0.043 to 0.56, all p </= 0.031). Sclerostin and cortical vBMD were positively correlated in the entire cohort (r=0.35 to 0.50; both p < 0.013); split by age group, middle-aged women had positive correlations (r=0.45 to 0.61 age and, all p </= 0.021) between sclerostin and pQCT variables. No significant differences for physical activity were observed for serum DKK-1 concentrations. Serum sclerostin concentrations were positively associated with age and bone characteristics in premenopausal women; however, these findings were not evident for circulating DKK-1. Further research is needed to elucidate the mechanisms for the discordant results in these Wnt inhibitors.