title: Relative excess risk due to interaction: resampling-based confidence intervals.
abstract: Relative excess risk due to interaction (RERI) has been used to quantify the joint effects of 2 exposures in epidemiology. However, the construction of confidence intervals (CIs) for RERI is complicated by sparse cells. Assuming that the data contain no zero cells, here we propose constructing CIs for RERI using nonparametric and parametric bootstrap methods with a continuity correction, and compare these proposed methods to existing methods using 3 empirical examples and Monte Carlo simulations. Our results show that, when cell counts are not sparse, CIs resulting from the explored bootstrap methods are generally acceptable in terms of CI coverage and length, although computationally more demanding than existing methods. However, when cell counts are sparse, the proposed bootstrap methods using a continuity correction outperform existing methods and continue to provide acceptable CIs. The continuity correction is needed for the explored bootstrap methods to provide acceptable CIs because resampled data sets may contain zero cells even when the observed data do not.
authors.affiliation: Division of Biometrics IV, Office of Biometrics/OTS/CDER/FDA, Silver Spring, MD 20993-0002, USA. lei.nie@fda.hhs.gov
authors.forename: Lei
authors.initials: L
authors.lastname: Nie
authors.forename: Haitao
authors.initials: H
authors.lastname: Chu
authors.forename: Feng
authors.initials: F
authors.lastname: Li
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Cole
mesh_terms: D000367:Age Factors; D000428:Alcohol Drinking / Q000009:adverse effects; D001794:Blood Pressure; D015992:Body Mass Index; D016001:Confidence Intervals; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000209:etiology; D008159:Lumbar Vertebrae; D008297:Male; D008875:Middle Aged; D009010:Monte Carlo Method; D009062:Mouth Neoplasms / Q000209:etiology; D012306:Risk; D018401:Sample Size; D012907:Smoking / Q000009:adverse effects; D013177:Sports / Q000706:statistics & numerical data; D013223:Statistics as Topic / Q000379:methods