Heederik D, Miller B G
Department of Environmental and Tropical Health and Air Pollution, Agricultural University, Wageningen, The Netherlands.
Int J Epidemiol. 1988 Dec;17(4):970-4. doi: 10.1093/ije/17.4.970.
Epidemiological studies often estimate the health effects of occupational exposures by multiple regression techniques. The standard theory of regression analysis is based on the assumption that the explanatory variables are known without error, and it has long been realised that departures from this assumption will lead to underestimation of the true regression coefficients. In reality, there may be considerable imprecision in the measurement of individuals' exposures to hazards in the workplace, but this is seldom taken into account in analyses. We therefore studied the effect of allowing for imprecision in the exposure estimate with more sophisticated statistical methods, using lung function data from a sample of 348 British miners exposed to mixed coal dust, over an eight-year period. Change in lung function over an eight-year period was regressed on cumulative dust exposure, weight, age and smoking habits. The error in the exposure estimation was assumed to be up to 30% of the total varience of the distribution of the exposure. Adjustment of the regression coefficients of lung function change on dust exposure for the estimation error using linear structural relationships increased the regression coefficient more than threefold compared with those calculated by standard regression analysis. The adjustment led to a change of the coefficients of age as well. The results indicate that a serious underestimation of the relation between lung function change and occupational exposure may occur, which might lead to false interpretations about the relative importance of the occupational exposure as a determinant of disease.
流行病学研究常常运用多元回归技术来评估职业暴露对健康的影响。回归分析的标准理论基于这样一个假设：解释变量的测量是准确无误的，并且人们早就认识到，偏离这一假设会导致对真实回归系数的低估。在现实中，个体在工作场所接触危害因素的测量可能存在相当大的不精确性，但在分析中很少考虑到这一点。因此，我们运用更复杂的统计方法，以348名接触混合煤尘的英国矿工样本在八年期间的肺功能数据，研究了在暴露估计中考虑不精确性的影响。将八年期间的肺功能变化与累积粉尘暴露、体重、年龄和吸烟习惯进行回归分析。假设暴露估计中的误差高达暴露分布总方差的30%。使用线性结构关系对粉尘暴露导致的肺功能变化回归系数进行估计误差调整后，与标准回归分析计算出的系数相比，回归系数增加了三倍多。这种调整也导致了年龄系数的变化。结果表明，可能会严重低估肺功能变化与职业暴露之间的关系，这可能会导致对职业暴露作为疾病决定因素的相对重要性产生错误解读。
