Blood lead levels and bone turnover with weight reduction in women

High bone turnover states are known to raise blood lead levels (BPb). Caloric restriction will increase bone turnover, yet it remains unknown if weight reduction increases BPb due to mobilization of skeletal stores. We measured whole blood Pb levels (²⁰⁶Pb) by inductively coupled plasma mass spectrometry in 73 women (age 24-75 years; BMI 23- 61 kg/m²) before and after 6 months of severe weight loss (S-WL), moderate weight loss (M-WL), or weight maintenance (WM). Baseline BPb levels were relatively low at 0.2-6.0 μg/dl, and directly associated with age (r=0.49, P<0.0001). After severe WL (-37.4±9.3 kg, n=17), BPb increased by 2.1±3.9 μg/dl (P<0.05), resulting in BPb levels of 1.3-12.5 μg/dl. M-WL (-5.6±2.7 kg, n=39) and WM (0.3±1.3 kg, n=17) did not result in an increase in BPb levels (0.5±3.2 and 0.0±0.7 μg/dl, M-WL and WM, respectively). BPb levels increased more with greater WL (r=0.24, P<0.05). Bone turnover markers increased only with severe WL and were directly correlated with WL. At baseline, higher calcium intake was associated with lower BPb (r=-0.273, P<0.02), however, this association was no longer present after 6 months. Severe weight reduction in obese women increases skeletal bone mobilization and BPb, but values remain well below levels defined as Pb overexposure.