Landis J R, Flegal K M
Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor 48109.
Environ Health Perspect. 1988 Jun;78:35-41. doi: 10.1289/ehp.887835.
This paper proposes an alternative analysis of the statistically significant blood pressure/blood lead relationship reported for males, ages 12 to 74, based on data from the second National Health and Nutrition Examination Survey. Because of the substantial decline, both for blood lead levels and blood pressures, during the 4-year survey period, there is considerable interest in the extent to which this association can be attributed to concurrent secular trends. The statistical methods illustrate the use of a randomization model-based approach to testing the statistical significance of the partial correlation between blood lead level and diastolic blood pressure, adjusting for age, body mass index, and the 64 sampling sites. The resulting analyses confirm that the significant linear association between blood lead levels and diastolic blood pressures cannot be dismissed as a spurious association due to concurrent secular trends in the two variables across the 4-year survey period. In a conservative approach to this investigation, a randomization model-based test statistic, using the actual level of the natural log of blood lead and diastolic blood pressure, remained statistically significant at the 5% level, even when averaging the association across 478 subgroups formed by the cross-classification of age, body mass index, and the 64 sampling sites.
本文基于第二次全国健康与营养检查调查的数据，对报告的12至74岁男性的血压/血铅关系进行了另一种统计分析。由于在4年的调查期间血铅水平和血压都大幅下降，人们相当关注这种关联在多大程度上可归因于同期的长期趋势。统计方法展示了基于随机化模型的方法在检验血铅水平与舒张压之间的偏相关的统计显著性时的应用，同时对年龄、体重指数和64个采样地点进行了调整。结果分析证实，血铅水平与舒张压之间的显著线性关联不能被视为由于这两个变量在4年调查期间的同期长期趋势而产生的虚假关联。在这项调查的保守方法中，基于随机化模型的检验统计量，使用血铅自然对数和舒张压的实际水平，即使在对由年龄、体重指数和64个采样地点交叉分类形成的478个亚组的关联进行平均时，在5%的水平上仍具有统计学显著性。
