Lead levels in erythrocytes and biomarkers of bone turnover in pregnantand lactating women with marginal calcium intakes

摘要

The purpose of this study was to compare erythrocyte lead levels and relationship with biomarkers of bone turnover in pregnant (n = 68, 28-39 weeks of gestation), lactating (n = 45, 1-2 months post-partum) and control (n = 33) adult women with habitually low calcium intake (400-600 mg Ca/d) and low environmental lead exposure (blood lead levels < 10 mug/dL). Erythrocyte lead levels were similar in control and pregnant women (0.191-0.551 mug Pb/g protein) but lactating women had significantly (p < 0.01) higher levels (0.279-0.978 mug Pb/g protein). Parity influenced erythrocyte lead levels in the lactating women with higher levels in multiparae compared to primiparae (p < 0.05). Blood hemoglobin correlated negatively with erythrocyte lead in multiparous pregnant women (r = -0.407, p < 0.05) and in multiparous lactating women (r = -0.486, p < 0.05). Markers of bone degradation (urinary excretion of D-pyridinoline) and of bone formation (activity of bone-alkaline phosphatase in plasma) were significantly higher in the pregnant and lactating women compared to the control group but were not affected by parity. Erythrocyte lead levels correlated with urinary excretion of D-pyridinoline in multiparous pregnant women (r = 0.456, p 0.05) and in multiparous lactating women (r = 0.607, p < 0.01). Our results indicate that lactation increases erythrocyte lead levels in women not specifically exposed to lead and with low calcium intakes. Multiparous women may be more sensitive to the biological effects of bone lead mobilization with pregnancy and lactation than primiparous women.