@article{27a15c3022014e75a8869fcb7518f626,
title = "The effect of reverse causality and selective attrition on the relationship between body mass index and mortality in postmenopausal women",
abstract = "Concerns about reverse causality and selection bias complicate the interpretation of studies of body mass index (BMI) and mortality in older adults. The objective of this manuscript is to investigate methodological explanations for the apparent attenuation of obesity-related risks in older adults. We used data from 68,132 participants from the Women{\textquoteright}s Health Initiative (WHI) clinical trial in this analysis. All of the participants were postmenopausal women aged 50-79 at baseline (1993-1998). To examine reverse causality and selective attrition, we compared rate ratios from inverse probability of treatment (IPTW) and censoring (IPCW) weighted Poisson marginal structural models to results from an unweighted adjusted Poisson regression model. The estimated mortality rate ratios and 95% confidence intervals for BMI 30-34.9, 35-39.9 and >40 kg/m2 were 0.86 (0.77, 5.48), 0.85 (0.72, 0.99), and 0.88 (0.72, 1.07) in the unweighted model. The corresponding mortality rate ratios were 0.96 (0.86, 1.07), 1.12 (0.97, 1.29), and 1.31 (1.08, 1.57) in the marginal structural model. Results from the IPTW and IPCW weighted marginal structural model were attenuated in low BMI categories and increased in high BMI categories. The results demonstrate the importance of accounting for reverse causality and selective attrition in studies of older adults.",
keywords = "Aging, Body mass index, Reverse causality, Selection bias, Selective attrition",
author = "Banack, {Hailey R.} and Bea, {Jennifer W.} and Kaufman, {Jay S.} and Andrew Stokes and Kroenke, {Candyce H.} and Stefanick, {Marcia L.} and Beresford, {Shirley A.} and Bird, {Chloe E.} and Lorena Garcia and Robert Wallace and Wild, {Robert A.} and Bette Caan and Jean Wactawski-Wende",
note = "Funding Information: Author affiliations: Department of Epidemiology and Environmental Health, School of Public Health and Health Professions, University at Buffalo, the State University of New York, Buffalo, New York (Hailey R. Banack, Jean Wactawski-Wende); Department of Nutritional Sciences, College of Agriculture and Life Sciences, University of Arizona, Tucson, Arizona (Jennifer W. Bea); Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Quebec (Jay S. Kaufman); Department of Global Health, School of Public Health, Boston University, Boston, Massachusetts (Andrew Stokes); Division of Research, Kaiser Permanente Northern California, Oakland, California (Candyce H. Kroenke, Bette Caan); Division of Cardiovascular Medicine, Department of Medicine, School of Medicine, Stanford University, Stanford, California, (Marcia L. Stefanick); Department of Epidemiology, School of Public Health, University of Washington, Seattle, Washington (Shirley A. Beresford); RAND Corporation, Santa Monica, California (Chloe E. Bird); Department of Public Health Sciences, School of Medicine, University of California Davis, Sacramento, California (Lorena Garcia); Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa (Robert Wallace); and Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (Robert A. Wild). This work was supported by the National Heart, Lung, and Blood Institute of the National Institutes of Health (grants HHSN268201600018C, HHSN268201600001C, HHSN268201600002C, HHSN268201600003C, and HHSN268201600004C) and the Banting Postdoctoral Fellowship Program from the Canadian Institute of Health Research. WHI Program Office: National Heart, Lung, and Blood Institute, Bethesda, Maryland—Jacques Rossouw, Shari Ludlam, Joan McGowan, Leslie Ford, and Nancy Geller. WHI Clinical Coordinating Center: Fred Hutchinson Cancer Research Center, Seattle, Washington—Garnet Anderson, Ross Prentice, Andrea LaCroix, and Charles Kooperberg. WHI Investigators and Academic Centers: Brigham and Women{\textquoteright}s Hospital, Harvard Medical School, Boston, Massachusetts—JoAnn E. Manson; MedStar Health Research Institute/Howard University, Washington, DC— Barbara V. Howard; Stanford Prevention Research Center, Stanford, California—M.L.S.; The Ohio State University, Columbus, Ohio—Rebecca Jackson; University of Arizona, Tucson/Phoenix, Arizona—Cynthia A. Thomson; University at Buffalo, Buffalo, New York—J.W.-W.; University of Florida, Gainesville/Jacksonville, Florida— Marian Limacher; University of Iowa, Iowa City/Davenport, Iowa—Jennifer Robinson; University of Pittsburgh, Pittsburgh, Pennsylvania—Lewis Kuller; Wake Forest University School of Medicine, Winston-Salem, North Carolina—Sally Shumaker; University of Nevada, Reno, Nevada—Robert Brunner; University of Minnesota, Minneapolis, Minnesota—Karen L. Margolis. WHI Memory Study: Wake Forest University School of Medicine, Winston-Salem, North Carolina—Mark Espeland. Conflict of interest: none declared. Funding Information: This work was supported by grants HHSN268201600018C, HHSN268201600001C, HHSN268201600002C, HHSN268201600003C, and HHSN268201600004C from the National Heart, Lung, and Blood Institute, National Institutes of Health, U.S. Department of Health and Human Services and the Banting Postdoctoral Fellowship Program from the Canadian Institute of Health Research. GIN Publisher Copyright: {\textcopyright} The Author(s) 2019. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved.",
year = "2019",
month = oct,
day = "1",
doi = "10.1093/aje/kwz160",
language = "English (US)",
volume = "188",
pages = "1838--1848",
journal = "American Journal of Epidemiology",
issn = "0002-9262",
publisher = "Oxford University Press",
number = "10",
}