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Joint semiparametric mean-covariance model in longitudinal study

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Abstract

Semiparametric regression models and estimating covariance functions are very useful for longitudinal study. To heed the positive-definiteness constraint, we adopt the modified Cholesky decomposition approach to decompose the covariance structure. Then the covariance structure is fitted by a semiparametric model by imposing parametric within-subject correlation while allowing the nonparametric variation function. We estimate regression functions by using the local linear technique and propose generalized estimating equations for the mean and correlation parameter. Kernel estimators are developed for the estimation of the nonparametric variation function. Asymptotic normality of the the resulting estimators is established. Finally, the simulation study and the real data analysis are used to illustrate the proposed approach.

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References

  1. Diggle P T, Heagerty P J, Liang K, et al. Analysis of Longitudinal Data, 2nd ed. Oxford Statistical Science Series. Oxford: Oxford University Press, 2002

    Google Scholar 

  2. Diggle P, Verbyla A. Nonparametric estimation of covariance structure in longitudinal data. Biometrics, 1998, 54: 401–415

    Article  MATH  Google Scholar 

  3. Fan J, Huang T. Profile likelihood inferences on semiparametric varying coefficient partially linear models. Bernoulli, 2005, 11: 1031–1059

    Article  MATH  MathSciNet  Google Scholar 

  4. Fan J, Huang T, Li R. Analysis of longitudinal data with semiparametric estimation of covariance function. J Amer Statist Assoc, 2007, 100: 632–641

    Article  MathSciNet  Google Scholar 

  5. Fan J, Li R. New estimation and model selection procedures for semiparametric modeling in longitudinal data analysis. J Amer Statist Assoc, 2004, 99: 710–723

    Article  MATH  MathSciNet  Google Scholar 

  6. Fan J, Wu Y. Semiparametric estimation of covariance matrices for longitudinal data. J Amer Statist Assoc, 2008, 103: 1520–1533

    Article  MathSciNet  Google Scholar 

  7. Fan J, Zhang W. Statistical estimation in varying-coefficient models. J Amer Statist Assoc, 1999, 27: 1491–1518

    MATH  MathSciNet  Google Scholar 

  8. Fan J, Zhang W. Two-step estimation of functional linear models with application to longitudinal data. J Roy Statist Soc Ser B, 2000, 62: 303–322

    Article  MathSciNet  Google Scholar 

  9. He X, Fung W K, Zhu Z Y. Robust estimation in generalized partial linear models for clustered data. J Amer Statist Assoc, 2005, 100: 1176–1184

    Article  MATH  MathSciNet  Google Scholar 

  10. He X, Zhu Z Y, Fung W K. Estimation in a semiparametric model for longitudinal data with unspecified dependence structure. Biometrika, 2002, 89: 579–590

    Article  MATH  MathSciNet  Google Scholar 

  11. Huang J Z, Wu C O, Zhou L. Varying-coefficient models and basis function approximations for the analysis of repeated measurements. Biometrika, 2002, 89: 111–128

    Article  MATH  MathSciNet  Google Scholar 

  12. Liang K Y, Zeger S L. Longitudinal data analysis using generalized linear model. Biometrika, 1986, 73: 13–22

    Article  MATH  MathSciNet  Google Scholar 

  13. Martinussen T, Scheike T H. A semiparametric additive regression model for longitudinal data. Biometrika, 1999, 86: 691–702

    Article  MATH  MathSciNet  Google Scholar 

  14. Pan J, Mackenzie G. Model selection for joint mean-covariance structures in longitudinal studies. Biometrika, 2003, 90: 239–244

    Article  MATH  MathSciNet  Google Scholar 

  15. Pourahmadi M. Joint mean-covariance models with applications to longitudinal data: unconstrained parameterisation. Biometrika, 1999, 86: 677–690

    Article  MATH  MathSciNet  Google Scholar 

  16. Pourahmadi M. Maximum likelihood estimation of generalized linear models for multivariate normal covariance matrix. Biometrika, 2000, 87: 425–435

    Article  MATH  MathSciNet  Google Scholar 

  17. Ruppert D, Shealther S J, Wand M P. An effect bandwidth selector for local least squares regression. J Amer Statist Assoc, 1995, 90: 1257–1270

    Article  MATH  MathSciNet  Google Scholar 

  18. Sun Y, Zhang W, Tong H. Estimation of the covariance matrix of random effects in longitudinal studies. Ann Statist, 2007, 35: 2795–2814

    Article  MATH  MathSciNet  Google Scholar 

  19. Wang H, Zhu Z, Zhou J. Quantile regression in partially linear varying coefficient models. Ann Statist, 2009, 37: 3841–3866

    Article  MATH  MathSciNet  Google Scholar 

  20. Wu W B, Pourahmadi M. Nonparametric estimation of large covariance matrices of longitudinal data. Biometrika, 2003, 90: 831–844

    Article  MathSciNet  Google Scholar 

  21. Ye H, Pan J. Modelling of covariance structure in generalised estimation equations for longitudinal data. Biometrika, 2006, 93: 927–941

    Article  MathSciNet  Google Scholar 

  22. Zeger S L, Diggle P J. Semiparametric models for longitudinal data with application to CD4 cell numbers in HIV seroconverters. Biometrics, 1994, 50: 689–699

    Article  MATH  Google Scholar 

  23. Zhang D W, Lin X H, Raz J, et al. Semiparametric stochastic mixed models for longitudinal data. J Amer Statist Assoc, 1998, 93: 710–719

    Article  MATH  MathSciNet  Google Scholar 

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Correspondence to ZhongYi Zhu.

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Mao, J., Zhu, Z. Joint semiparametric mean-covariance model in longitudinal study. Sci. China Math. 54, 145–164 (2011). https://doi.org/10.1007/s11425-010-4078-4

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  • DOI: https://doi.org/10.1007/s11425-010-4078-4

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