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Activity Number:
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480
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Type:
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Contributed
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Date/Time:
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Wednesday, August 1, 2007 : 2:00 PM to 3:50 PM
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Sponsor:
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Section on Statistics in Epidemiology
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| Abstract - #310338 |
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Title:
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Impact of Duration of Follow-Up Time on Predictors of Cardiovascular Disease in Survival Models
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Author(s):
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Lei Zhu*+ and Michael J. Pencina and Ralph B. D'Agostino, Sr.
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Companies:
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Boston University and Boston University and Boston University
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Address:
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16 Walnut street Apt 42, Arlington, MA, 02476,
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Keywords:
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cardiovascular disease ; risk factors ; proportional hazard model ; duration of follow-up
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Abstract:
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Many cardiovascular disease (CVD) risk factors were identified over a specified time frame in the Framingham Heart Study. However, whether longer or shorter duration of follow-up affects the magnitude and significance of the effects remains uncertain. We used the Framingham Heart Study data to assess the impact of numerous predictors on the risk of CVD and potential changes of this impact during different durations of follow-up. Sex-specific multivariate Cox regression models were performed. We found that for some risk factors the magnitude or/and significance of the effect on CVD changed with time. For example, obesity in men was significantly related to CVD in a 5-year period, but lost significance in longer term. Our research suggests that risk assessment methods which assume constancy of effects regardless of duration of follow-up may overestimate or underestimate true relationships.
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