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Keith Humphreys


Department and organisational affiliation:

About me

I obtained my doctoral degree in Statistics at Southampton University (U.K.) in 1996. In 2005, I was appointed Senior Lecturer in Biostatistics at Karolinska Institutet at the Department of Medical Epidemiology and Biostatistics. I am interested in a broad range of statistical methods topics such as measurement error, longitudinal data analysis, statistical genetics, graphical modeling and machine learning. I have been heavily involved, since 2001, in genetic association and other epidemiological, studies of breast cancer, at Karolinska Institutet and have published on genetic risk prediction models of breast cancer.

Research description

I am involved in a number of research projects which have a general aim to contribute to the identification of women with high risk for breast cancer, in particular that which is aggressive/has poor prognosis. We develop novel statistical approaches and applying them to some of the world’s most detailed studies of breast cancer/mammography screening. My research builds on previous work on the identification of genetic variants for breast cancer, the development of statistical models of breast cancer risk and tumour growth and the development of novel approaches for measuring mammographic density.  

Ten selected publications

  • Abrahamsson L and Humphreys K. (2013) A statistical model of breast cancer tumour growth with estimation of screening sensitivity as a function of mammographic density. Statistical Methods in Medical Research. 2013 Jul 9 [Epub ahead of print].
  • Darabi H, Czene K, Zhao W, Liu J, Hall P, Humphreys K. (2012) Breast Cancer risk prediction and individualized screening based on common genetic variation and breast density measurement. Breast Cancer Research 14:R25.
  • Darabi H and Humphreys K. (2011) Single SNP and pathway tests of genetic association incorporating phenotype heterogeneity. Human Heredity. 71; 11-22. 
  • Humphreys K, Grankvist A, Leu M, Hall P, Ripatti S, Groop L, Klareskog L, Grönberg H, Pedersen NL, Mattingsdal M, Andreassen OA, Lichtenstein P, Purcell S, Sklar P, Sullivan P, Hultman C, Palmgren J, Magnusson P. (2011) The Genetic Structure of the Swedish population. PLoS One. 6(8):e22547.
  • Grunewald M, Humphreys K and Hössjer O. (2010) A stochastic EM type algorithm for parameter estimation in models with continuous outcomes, under complex ascertainment. International Journal of Biostatistics. Vol.6: Iss. 1, Article 23.
  • Sjölander A, Vansteelandt S. and Humphreys K. (2010) A principal stratification approach to assess the differences in prognosis between cancers caused by hormone replacement therapy and by other factors. International Journal of Biostatistics. Vol.6: Iss. 1, Article 20.
  • Hössjer O, Hartman L and Humphreys K. (2009) Ancestral recombination graphs under nonrandom ascertainment with applications to gene mapping. Statistical Applications of Genetics and Molecular Biology. Vol. 8. Issue
  • Jonasdottir G, Humphreys K, Palmgren J. (2007) Testing Association in the Presence of Linkage - A powerful score for binary traits. Genetic Epidemiology. 31: 528-540.
  • Humphreys, K. and Titterington, D.M. (2003) Variational approximations for categorical causal modelling with latent variables. Psychometrika, 68: 391-412.
  • Hall, P., Humphreys, K. and Titterington, D.M. (2002). On the adequacy of variational lower bound functions for likelihood-based inference in Markovian models with missing values. Journal of the Royal Statistical Society, B, 64, 549-564. 
  • Skinner, C.J. and Humphreys, K. (1999). Weibull regression for lifetimes measured with error. Lifetime data analysis, 5, 23-37.



      Current supervision of PhD students and Postdoctoral researchers

      • Linda Abrahamsson (PhD student)
      • Abbas Cheddad   (Postdoc.)
      • Therese Andersson (Postdoc.) 


    • 1996, PhD (Social Statistics), Southampton University, U.K.
    • 1997, Postdoc (Statistics/Psychometrics), Stockholm University.
    • 1999, Postdoc (Statistics), Glasgow University, U.K.
    • 2002, Docent (Biostatistics), Karolinska Institutet.
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