Meeker John D, Rossano Mary G, Protas Bridget, Diamond Michael P, Puscheck Elizabeth, Daly Douglas, Paneth Nigel, Wirth Julia J
Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA.
Environ Health Perspect. 2008 Nov;116(11):1473-9. doi: 10.1289/ehp.11490. Epub 2008 Jul 1.
Evidence on human semen quality as it relates to exposure to various metals, both essential (e.g., zinc, copper) and nonessential (e.g., cadmium, lead), is inconsistent. Most studies to date used small sample sizes and were unable to account for important covariates.
Our goal in this study was to assess relationships between exposure to multiple metals at environmental levels and human semen-quality parameters.
We measured semen quality and metals in blood (arsenic, Cd, chromium, Cu, Pb, manganese, mercury, molybdenum, selenium, and Zn) among 219 men recruited through two infertility clinics. We used multiple statistical approaches to assess relationships between metals and semen quality while accounting for important covariates and various metals.
Among a number of notable findings, the associations involving Mo were the most consistent over the various statistical approaches. We found dose-dependent trends between Mo and declined sperm concentration and normal morphology, even when considering potential confounders and other metals. For example, adjusted odds ratios (ORs) for below-reference semen-quality parameters in the low, medium, and high Mo groups were 1.0 (reference), 1.4 [95% confidence interval (CI), 0.5-3.7], and 3.5 (95% CI, 1.1-11) for sperm concentration and 1.0 (reference), 0.8 (95% CI, 0.3-1.9), and 2.6 (95% CI, 1.0-7.0) for morphology. We also found preliminary evidence for interactions between Mo and low Cu or Zn. In stratified analyses, the adjusted ORs in the high Mo/low Cu group were 14.4 (1.6, 132) and 13.7 (1.6, 114) for below-reference sperm concentration and morphology, respectively.
Our findings represent the first human evidence for an inverse association between Mo and semen quality. These relationships are consistent with animal data, but additional human and mechanistic studies are needed.
关于人类精液质量与接触各种金属（包括必需金属，如锌、铜；以及非必需金属，如镉、铅）之间关系的证据并不一致。迄今为止，大多数研究样本量较小，且无法考虑重要的协变量。
本研究的目的是评估环境水平下多种金属暴露与人类精液质量参数之间的关系。
我们对通过两家不孕不育诊所招募的219名男性的精液质量和血液中的金属（砷、镉、铬、铜、铅、锰、汞、钼、硒和锌）进行了测量。我们使用多种统计方法来评估金属与精液质量之间的关系，同时考虑重要的协变量和各种金属。
在众多显著发现中，涉及钼的关联在各种统计方法中最为一致。我们发现钼与精子浓度下降和正常形态之间存在剂量依赖性趋势，即使考虑潜在的混杂因素和其他金属也是如此。例如，低、中、高钼组中低于参考精液质量参数的调整优势比（OR），精子浓度分别为1.0（参考值）、1.4 [95%置信区间（CI），0.5 - 3.7]和3.5（95% CI，1.1 - 11），形态分别为1.0（参考值）、0.8（95% CI，0.3 - 1.9）和2.6（95% CI，1.0 - 7.0）。我们还发现了钼与低铜或低锌之间相互作用的初步证据。在分层分析中，高钼/低铜组中低于参考精子浓度和形态的调整OR分别为14.4（1.6，132）和13.7（1.6，114）。
我们的研究结果首次为人类提供了钼与精液质量呈负相关的证据。这些关系与动物数据一致，但仍需要更多的人体和机制研究。
