The effect of smoking on bone metabolism: maternal and cord blood bone marker levels

BACKGROUND: To clarify the effect of smoking on bone metabolism in the fetus, we measured osteocalcin (OC), bone isoenzyme of alkaline phosphatase (BALP), procollagen type 1 C-terminal propeptide (PICP) in maternal serum and umbilical cord blood. METHODS: 15 active smoker, 14 passive smoker, 15 nonsmoker women and their newborn were included in this study. OC, BALP, PICP were determined by enzyme immunoassay. RESULTS: Of the bone markers tested only OC was different in the serum of the three groups of women. Infants of smoker women have significantly lower umbilical cord blood OC levels than those of infants from both passive smoker and nonsmoker women.(25.6 +/- 6.6, 35.8 +/- 10.4, 37.2 +/- 16.1 ng/mL respectively, p < 0.05). Infants of smoker women have significantly lower umbilical cord blood BALP levels than those of infants from nonsmoker women. (46 +/- 12, 57 +/- 15 U/L p < 0.05). All bone markers except total ALP were significantly higher in umbilical cord blood as compared to maternal blood levels (p < 0.001 for all). CONCLUSION: High umbilical cord blood bone marker levels may reflect the altered bone metabolism of fetus. Moreover, chronic hypoxia due to smoking may cause the suppression of bone matrix synthesis or placental synthesis as reflected by low OC and BALP levels in umbilical cord blood of infants from smoker women.