Variation in the Calculation of Allostatic Load Score: 21 Examples from NHANES.

After decades of resistance, there is now a genuine consensus that disease cannot be prevented or even successfully treated unless the role of stress is addressed alongside traditionally recognized factors such as genes and the environment. Measurement of allostatic load, which is quantified by the allostatic load score (ALS), is one of the most frequently used methods to assess the physiologic response to stress. Even though there is universal agreement that in the calculation of ALS, biomarkers from three categories should be included (cardiovascular, metabolic and immune), enormous variation exists in how ALS is calculated. Specifically, there is no consensus on which biomarkers to include or the method which should be used to determine whether the value of a biomarker represents high risk. In this perspective, we outline the approach taken in 21 different NHANES studies.