TY - JOUR
AU - Armstrong, Ben G
AB - ORIGINAL ARTICLE Fixed Factors that Modify the Effects of Time-Varying Factors: Applying the Case-Only Approach Ben G Armstrong he last 10 years have seen many studies of the depen- Background: The effects of air pollution or weather on mortality Tdence of daily mortality or hospital admissions in cities may be stronger in susceptible groups. Conventional investigation of on daily concentrations of ambient pollution in the same such effect modification through interaction terms in time-series city. Similar designs are used to study effects of changing regression analysis depends on hard-to-verify modeling assump- weather on health, and can be used to study acute effects of tions, and can be computationally unwieldy. As an alternative, we any risk factor that changes over time. Recently, several investigate the use of case-only approaches originally proposed for studies have focused on whether the pollution effect is mod- studying gene– environment interactions. ified by factors that might affect the vulnerability of subjects, Methods: We consider an investigation of whether persons of low such as pre-existing disease and socio-economic status socio-economic status (SES) are more susceptible to the effect 2,3 of high outside temperatures on mortality. If low SES persons (SES). The conventional approach to the investigation 
TI - Fixed Factors that Modify the Effects of Time-Varying Factors: Applying the Case-Only Approach
JF - Epidemiology
DO - 10.1097/01.ede.0000071408.39011.99
DA - 2003-07-01
UR - https://www.deepdyve.com/lp/wolters-kluwer-health/fixed-factors-that-modify-the-effects-of-time-varying-factors-colon-HQcHic69BK
SP - 467
EP - 472
VL - 14
IS - 4
DP - DeepDyve
ER -