248412 Social isolation is a better predictor of mortality than traditional clinical risk factors in certain populations

Sunday, October 30, 2011

Matthew S. Pantell, MS , Joint Medical Program, UC Berkeley - UCSF, Berkeley, CA
David Rehkopf, ScD, MPH , Division of General Medical Disciplines, Stanford University School of Medicine, Stanford, CA
Douglas Jutte, MD, MPH , Joint Medical Program, UC Berkeley - UCSF, Berkeley, CA
Leonard Syme, PhD , University of California Berkeley, School of Public Health, Berkeley, CA
John R. Balmes, MD , School of Public Health, University of California Berkeley, School of Medicine, University of California San Francisco, Berkeley, CA
Nancy E. Adler, PhD , Center for Health and Community, University of California, San Francisco, San Francisco, CA
Background: Social isolation has been linked to mortality across a range of middle-aged and older populations, although it has not been compared with other clinical risk factors in a national sample. Methods: Data came 12,403 adults from the National Health and Nutrition Examination Survey III and the National Death Index. The outcome was mortality after eight years. Predictor variables included individual social isolation factors and a composite score. Clinical predictors used for comparison included smoking, BMI, high blood pressure, and hypercholesterolemia. Logistic regressions and recursive partitioning - which classifies populations into low- and high- risk groups by choosing the best predictor variables were used to rank the importance of these predictors. Models were nationally weighted. Results: Male mortality was significantly predicted by current smoking (OR 1.81, CI 1.31-2.51), high blood pressure (OR 1.40, CI 1.06-1.85), and, most strongly, by social isolation (OR 2.25, CI 1.51-3.35). Only smoking (OR 2.33, CI 1.60-3.40) predicted mortality among females, although social isolation approached significance (OR 1.55, CI 0.99-2.44). For males, significant individual social isolation factors included being unmarried (OR 1.67, CI 1.20-2.31), not participating in religious activities (OR 1.31, 1.04-1.63), and lacking club/organization associations (OR 1.29, CI 1.00-1.67). Recursive partitioning identified social isolation factors as the most important predictors of mortality for young men. Conclusions: Social isolation is an equal if not better predictor of mortality than traditional clinical risk factors among males. It suggests that evaluating patients' social isolation in a clinical setting to identify individuals at high risk for mortality could be valuable.

Learning Areas:
Epidemiology
Public health or related research
Social and behavioral sciences

Learning Objectives:
1. Define social isolation and how it can be measured 2. Discuss which socially isolated populations may be at higher risk of mortality 3. Compare traditional clinical risk factors and social isolation as predictors of mortality 4. Describe how classification and regression tree analysis (CART) can be applied to epidemiology and clinical medicine 3.

Keywords: Adult Health, Mortality

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I have a master's in health and medical sciences, conduct social epidemiology research, work in a center for health and community, and am currently a medical student.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.