Abstract

     Low hemoglobin (Hb) level or anemia is associated with osteoporosis and bone fracture. Cadmium (Cd) and lead (Pb) exposure are also risk factors of osteoporosis and anemia. However, the role of anemia in Cd/Pb related bone loss remains unclear. The aim of present study was to investigate the association between Hb level and bone loss in a population with environmental lead and cadmium exposure. One hundred and ninety-four women and 108 men with different levels of Cd/Pb exposure were included in our study. The Cd/Pb exposure was determined using graphite-furnace atomic absorption spectrometry. Forearm bone mineral density (BMD) was determined by peripheral dual-energy X-ray absortiometry. Hb concentration was determined using an automatic blood cellcounter. A logistic model was established to predict the risk of osteoporosis. The BMDs of women that had the highest quartile BCd and BPb were markedly lower than that with the lowest quartile (p < ۰٫۰۵). The BMD and the prevalence of osteoporosis in men with anemia were lower and higher than that with normal Hb (p < ۰٫۰۵), respectively. In men, age, BPb and anemia were independent risk factors for osteoporosis. The odds ratio (OR) of men with anemia was 11.28 (95%confidence interval (CI):1.94-65.54) and 19.56 (95%CI: 2.98-128.78) compared to those with normal Hb after adjusting for potential cofounders. No such association was found in women. The area under the curve was 0.88 (95%CI: 0.82-0.96) in predicting osteoporosis using the logistic model in men. Linear discriminant analysis also showed that 90.7% of osteoporosis was correctly classified. Our data show that anemia is associated with incident of osteoporosis in men but not in women that environmentally exposed to Pb and Cd.

Introduction

     Cadmium (Cd) and lead (Pb) are both distributed in the environment and used in industrial field. Both Cd and Pb can enter the human body via digestive tract. Bone is an important target organ for Cd and Pb toxicity. Cd and Pb exposure are associated with low bone mass or osteoporosis (A˚ kesson et al., 2014; Jalili et al., 2020; Li et al., 2016). Moreover, both animal and population studies indicated that Cd and Pb exposure can affect hemoglobin (Hb) level, in particular to Pb exposure. Chronic Pb exposure is a risk factor of hematologic impairments that can decrease the Hb content (Dobrakowski et al. 2015; Li et al., 2018; Nakhaee et al. 2018) and hematocrit (Chwalba et al. 2019; Nakhaee et al. 2018). However, the association and interplay between those outcomes has not been completely clarified (Zhang et al., 2020).

Conclusion

     In conclusion, we observe that anemia is a negative and independent risk of osteoporosis in men but not in women that environmentally exposed to Cd and Pb. Age, BPb and anemia are important factors that are related to osteoporosis in men. A model based on the three factors showed acceptable performance in predicting osteoporosis. Hb level or anemia should be considered when aim to show the association between Pb or Cd exposure and bone loss, in particular to men population