The likelihood of an epidemiologic study correctly identifying an adverse health outcome associated with exposure to indoor air pollutants is increased if a) substantial variation exists in the frequency or level of exposure among study subjects otherwise at similar risk of the health outcome; b) the number of study subjects or study communities is large; c) the health outcome can be assessed w...

In vivo X-ray fluorescence (XRF) measurement of bone lead concentration (XRF) has emerged as an important technique for future epidemiological studies of long-term toxicity. Several issues germane to epidemiologic methodology need to be addressed, however. First, sources of variability in measurements of bone lead need to be quantified, including imprecision related to the physical measurement ...

Observational methods are important in the measurement of vaccine effectiveness (VE) as experimental designs cannot be used for measurement of vaccines already on the vaccination schedule. Furthermore, efficacy measured in clinical trials under ideal conditions may differ to effectiveness in the field under non-ideal conditions and in different populations. In addition to post-licensure surveil...

Interactions measured on the additive scale are more relevant than multiplicative interaction for assessing public health importance and also more closely related to notions of mechanistic synergism. Most work on sample size and power calculations for interaction have focused on the multiplicative scale. Here we derive analytic expressions for sample size and power calculations for interactions...

Genetic epidemiology is a hybrid discipline with a relatively short history of less than 50 years. The first mention of "epidemiologic genetics" can be found in the 1954 book by Neel and Schull (1), who suggested that the two parent disciplines must consider each other's strategies when studying common diseases such as cancer, diabetes, and heart disease that reflect joint effects of both genes...

A recent article in the Journal by Whelton et al. (Am J Epidemiol. 2013;178(7):1076-1084) prompted this commentary about the use of the word "elevated" in medical reports. We believe that the word used in that particular report should have been "higher." The exposure variable was not actually elevated according to what we understand the word to mean in epidemiologic research. Consistent with th...