Association between circulating CD34- positive cells and serum alkaline phosphatase in relation to body mass index for elderly Japanese men

Background: Recent studies have confirmed an association between bone metabolism and vascular homeostasis. However, no study has examined the relationship between serum alkaline phosphatase (ALP) (a marker of bone metabolism) and circulating immature cell such as CD34-positive cells (a marker of vascular homeostasis). Methods: We conducted a cross-sectional study of this association in 272 elderly Japanese men (60-79 years). Because low body mass index (BMI) status is a known characteristic of Japanese with a high incidence rate of stroke, we used a stratified analysis based on BMI. Results: Multivariable linear regression analysis adjusted for confounding factors showed a significant correlation between serum ALP and the number of circulating CD34-positive cells, especially for participants with low BMI (<23 kg/m²). The parameter estimates (β) and 95 % confidence intervals (CI) for one standard deviation increments in serum ALP levels (62 IU/L) for the circulating CD34-positive cell count were β = 0.25 (0.04, 0.45) for total subjects, β = 0.45 (0.16, 0.75) for participants with low BMI (<23 kg/m²), and β = 0.04 (-0.25, 0.34) for participants with high BMI (≥23 kg/m²). Conclusion: Serum ALP correlates positively with circulating CD34-positive cells among a general population of elderly Japanese men, especially those with low BMI (<23 kg/m²). These findings suggest that serum ALP levels may constitute an efficient tool for estimating the risk of insufficient vascular homeostasis, especially for participants with relatively few classical cardiovascular risk factors.