Effects of time-varying exposures adjusting for time-varying confounders: the case of alcohol consumption and risk of incident human immunodeficiency virus infection.
OBJECTIVE
Discuss issues related to time-varying exposures using as an example the recently meta-analyzed literature (Baliunas et al. in Int J Public Health, 2009) on alcohol consumption and risk of HIV infection.


METHODS
Cataloged sources of bias and imprecision in the context of time-varying exposures.


RESULTS
Confounding, selection, or measurement bias may occur when standard regression approaches are used to estimate effects of time-varying exposures. The reviewed literature on alcohol consumption and HIV infection suffer from one or more of these biases.


CONCLUSIONS
Detailed prospective data and thoughtful implementation of appropriate statistical methods are needed to obtain unbiased estimates of time-varying exposures, such as alcohol consumption.
Department of Epidemiology, Gillings School of Global Public Health, The University of North Carolina, McGavran-Greenberg Hall, Campus Box 7435, Chapel Hill, NC 27599-7435, USA. cjhowe@email.unc.edu
Chanelle J
CJ
Howe
Petra M
PM
Sander
Michael W
MW
Plankey
Stephen R
SR
Cole
D000428:Alcohol Drinking; D015982:Bias; D015658:HIV Infections / Q000209:etiology*; D006801:Humans; D018570:Risk Assessment; D013997:Time Factors