Zwicker Jennifer D, Dutton Daniel J, Emery John Charles Herbert
School of Public Policy, University of Calgary, Calgary, AB T2P 1H9, Canada.
Environ Health. 2014 Nov 18;13:95. doi: 10.1186/1476-069X-13-95.
Mercury vapor poses a known health risk with no clearly established safe level of exposure. Consequently there is debate over whether the level of prolonged exposure to mercury vapor from dental amalgam fillings, combining approximately 50% mercury with other metals, is sufficiently high to represent a risk to health. The objective of our study is to determine if mercury exposure from amalgam fillings is associated with risk of adverse health effects.
In a large longitudinal non-blind sample of participants from a preventative health program in Calgary, Canada we compared number of amalgam fillings, urine mercury measures and changes in 14 self-reported health symptoms, proposed to be mercury dependent sub-clinical measures of mental and physical health. The likelihood of change over one year in a sample of persons who had their fillings removed was compared to a sample of persons who had not had their fillings removed. We use non-parametric statistical tests to determine if differences in urine mercury were statistically significant between sample groups. Logistic regression models were used to estimate the likelihood of observing symptom improvement or worsening in the sample groups.
At baseline, individuals with dental amalgam fillings have double the measured urine mercury compared to a control group of persons who have never had amalgam fillings. Removal of amalgam fillings decreases measured urine mercury to levels in persons without amalgam fillings. Although urine mercury levels in our sample are considered by Health Canada to be too low to pose health risks, removal of amalgam fillings reduced the likelihood of self-reported symptom deterioration and increased the likelihood of symptom improvement in comparison to people who retained their amalgam fillings.
Our findings suggest that mercury exposure from amalgam fillings adversely impact health and therefore are a health risk. The use of safer alternative materials for dental fillings should be encouraged to avoid the increased risk of health deterioration associated with unnecessary exposure to mercury.
汞蒸气对健康构成已知风险，且尚无明确确定的安全暴露水平。因此，对于牙科汞合金填充物（约含50%汞与其他金属）长期暴露的汞水平是否高到足以对健康构成风险存在争议。我们研究的目的是确定汞合金填充物导致的汞暴露是否与不良健康影响风险相关。
在加拿大卡尔加里一项预防性健康计划的大型纵向非盲样本参与者中，我们比较了汞合金填充物数量、尿汞测量值以及14种自我报告的健康症状的变化情况，这些症状被认为是依赖汞的身心健康亚临床指标。将补牙填充物被移除的人群样本在一年内症状变化的可能性与未移除补牙填充物的人群样本进行比较。我们使用非参数统计检验来确定样本组之间尿汞差异是否具有统计学意义。使用逻辑回归模型来估计样本组中观察到症状改善或恶化的可能性。
在基线时，有牙科汞合金填充物的个体与从未有过汞合金填充物的对照组相比，测量的尿汞含量高出一倍。移除汞合金填充物可使测量的尿汞水平降至没有汞合金填充物的人的水平。尽管加拿大卫生部认为我们样本中的尿汞水平过低，不会对健康构成风险，但与保留汞合金填充物的人相比，移除汞合金填充物降低了自我报告症状恶化的可能性，并增加了症状改善的可能性。
我们的研究结果表明，汞合金填充物导致的汞暴露对健康有不利影响，因此是一种健康风险。应鼓励使用更安全的牙科填充替代材料，以避免因不必要的汞暴露而增加健康恶化的风险。
