Journal of Biometrics & Biostatistics

Ping Yao

Publications

• Research Article
  Semiparametric Analysis of Longitudinal Zero-inflated Count Dat a with Applications to Instrumental Activities of Daily Living
  Author(s): Ping Yao and Xiaohong LiuPing Yao and Xiaohong Liu
  
  Background: The instrumental activities of daily living (IADLs) are important index of physical functioning in older adult studies. These count outcomes with a large proportion of zeros are often collected in longitudinal studies. Data were from the Hispanic Established Population for Epidemiological Study of the Elderly (HEPESE), a four wave (seven years) longitudinal study of community-dwelling elderly Mexican-Americans. There were excess zeros IADLs observed during follow-up. Methods: We present semiparametric zero-inflated Poisson (ZIP) and hurdle model with random effects to evaluate IADLs in the context of excess zeros. Results: Age, education, household income, marital status, smoking, cognitive functioning and prescription medication use were not significantly associated with IADLs. The counts of IADLs changed with age nonlinearly. .. Read More»
  DOI: 10.4172/2155-6180.1000172

  Abstract PDF