In this tutorial, we provide a broad introduction to the topic of interaction between the effects
of exposures. We discuss interaction on both additive and multiplicative scales using risks, …

Measures of interaction on an additive scale (relative excess risk due to interaction [RERI],
attributable proportion [AP], synergy index [S]), were developed for risk factors rather than …

Analysis domly assigned to groups receiving surgery followed by radiotherapy, or radiotherapy
alone. 12 The primary outcome was the ability to walk, which occurred in 70.3% of the …

Background To determine the presence of interaction in epidemiologic research, typically a
product term is added to the regression model. In linear regression, the regression coefficient …

Infections with the Omicron SARS-CoV-2 variant are rapidly increasing worldwide. Among
174,349 SARS-CoV-2-infected individuals (≥ 12 years), we observed an increased risk of S …

Background: Interaction refers to the situation in which the effect of 1 exposure on an
outcome differs across strata of another exposure. We did a survey of epidemiologic studies …

Authors often do not give sufficient information to draw conclusions about the size and statistical
significance of interaction on the additive and multiplicative scales. To improve this, we …

In randomized controlled trials as well as in observational studies, researchers are often
interested in effects of treatment or exposure in different subgroups, ie effect modification [1, 2]. …

Background Since 2009, the incidence of meningococcal serogroup W disease has increased
rapidly in the UK because of a single strain (the so-called original UK strain) belonging to …

OBJECTIVE: Missing indicator method (MIM) and complete case analysis (CC) are frequently
used to handle missing confounder data. Using empirical data, we demonstrated the …