that the association disappears when cardiovascular disease and cognitive function are considered. Tzuo-Yun Lan, PhD Institute of Population Health Sciences National Health Research Institutes Miaoli County, Taiwan China Medical University Taichung City, Taiwan Wen-Chiung Chang, MS Institute of Population Health Sciences National Health Research Institutes Miaoli County, Taiwan Tsuo-Hung Lan, MD, PhD Institute of Population Health Sciences National Health Research Institutes Miaoli County, Taiwan Department of Psychiatry National Yang-Ming University Taipei City, Taiwan Department of Psychiatry Taichung Veterans General Hospital Taichung City, Taiwan Baai-Shyun Hurng, PhD Population and Health Research Center Bureau of Health Promotion Taichung City, Taiwan ACKNOWLEDGMENTS The SEBAS was supported by the Demography and Epidemiology Unit of the Behavioral and Social Research Program of the National Institute on Aging. This study was based on data from the SEBAS provided by the Population and Health Research Center, Bureau of Health Promotion in Taiwan. The interpretation and reporting of these data are the sole responsibility of the authors. Conflict of Interest: The editor in chief has reviewed the conflict of interest checklist provided by the authors and has determined that the authors have no financial or any other kind of personal conflicts with this letter. Author Contributions: Conception and design: T-Y Lan. Acquisition of data, analysis and interpretation of data: T-Y Lan and W-C Chang. Manuscript drafting: T-Y Lan and T-H Lan. Manuscript revision for important intel- lectual content: B-S Hurng. Sponsor’s Role: The sponsor plays no role in the design, methods, subject recruitment, data collections, analysis, or preparation of the letter. REFERENCES 1. Smith JD. Apolipoproteins and aging: Emerging mechanisms. Ageing Res Rev 2002;1:345–365. 2. Albert SM, Gurland B, Maestre G et al. APOE genotype influences functional status among elderly without dementia. Am J Med Genet 1995;60:583–587. 3. Bader G, Zuliani G, Kostner GM et al. Apolipoprotein E polymorphism is not associated with longevity or disability in a sample of Italian octo- and nona- genarians. Gerontology 1998;44:293–299. 4. Blazer DG, Fillenbaum G, Burchett B. The APOE-E4 allele and the risk of functional decline in a community sample of African American and white older adults. J Gerontol A Biol Sci Med Sci 2001;56A:M785–M789. 5. Carmelli D, DeCarli C, Swan GE et al. The joint effect of apolipoprotein E epsilon4 and MRI findings on lower-extremity function and decline in cognitive function. J Gerontol A Biol Sci Med Sci 2000;55A:M103–M109. 6. Fried LP, Ettinger WH, Lind B et al. Physical disability in older adults: A physiological approach. Cardiovascular Health Study Research Group. J Clin Epidemiol 1994;47:747–760. 7. Goldman N, Turra CM, Glei DA et al. Predicting mortality from clinical and nonclinical biomarkers. J Gerontol A Biol Sci Med Sci 2006;61A:M1070– M1074. 8. Fried LP, Guralnik JM. Disability in older adults: Evidence regarding signifi- cance, etiology, and risk. J Am Geriatr Soc 1997;45:92–100. 9. Stuck AE, Walthert JM, Nikolaus T et al. Risk factors for functional status decline in community-living elderly people: A systematic literature review. Soc Sci Med 1999;48:445–469. 10. Melzer D, Dik MG, van Kamp GJ et al. The apolipoprotein E e4 polymor- phism is strongly associated with poor mobility performance test results but not self-reported limitation in older people. J Gerontol A Biol Sci Med Sci 2005;60A:M1319–M1323. INCIDENCE OF POSTOPERATIVE DELIRIUM IN A SPECIALIZED HOSPITAL FOR ORTHOPEDIC SURGERY To the Editor: Delirium is a serious postoperative complica- tion and is highly prevalent in elderly patients. It is associated with greater morbidity and mortality, longer hospital stay, and a high rate of institutionalization after discharge. 1 Next Table 1. Associations Between Apolipoprotein (APOE) Alleles and Risk of Mobility, Instrumental Activity of Daily Living (IADL), or Activity of Daily Living (ADL) Decline APOE Allele n Odds Ratio (95% Confidence Interval) Cases Controls Unadjusted Adjusted à Mobility decline group e2 Absent 77 77 1.00 1.00 Present 14 14 1.00 (0.43–2.31) 1.03 (0.42–2.49) e4 Absent 79 79 1.00 1.00 Present 12 12 1.00 (0.43–2.31) 1.18 (0.48–2.94) IADL decline group e2 Absent 65 70 1.00 1.00 Present 14 9 1.56 (0.67–3.59) 1.57 (0.62–3.97) e4 Absent 64 67 1.00 1.00 Present 15 12 1.33 (0.56–3.16) 1.46 (0.54–3.90) ADL decline group e2 Absent 29 28 1.00 1.00 Present 6 7 0.83 (0.25–2.73) 0.44 (0.03–6.18) e4 Absent 33 28 1.00 1.00 Present 2 7 0.29 (0.06–1.38) 0.36 (0.02–6.03) à Adjusted for body mass index and the following factors updated until the 2003 interview: heart disease, stroke, arthritis, cognitive impairment, and physical activity. LETTERS TO THE EDITOR 1309 JAGS JULY 2009–VOL. 57, NO. 7