My principal research interest is in the efficient computation of maximum likelihood estimates for single parameter exponential family and more general nonlinear regression models (generalized nonlinear models), and in the practical application of these models in biomedical research. An important aspect of this research is the application of the delta method to provide standard errors for nonlinear functions of model parameters. For example, a recent paper employed the delta method to provide a standard error for a new definition of the limit of quantitation for a laboratory assay in which actual concentrations are estimated from measured values by means of a linear calibration curve. A second paper involved an application of the delta method to provide a simplified computation of the standard error for a model-based estimate of the attributable risk under both case-control and cross-sectional sampling.

Since coming to STATEPI, I have become involved in several projects. I collaborated with Dr. Muñoz and Dr. Chu on a study of the generalized gamma family of parametric survival models. This family includes all of the common types of hazard under one umbrella, and provides a useful alternative to semi-parametric approaches that require the stringent assumption of proportional hazards. Graphical tools for the presentation of relative times and relative hazards are an important aspect of this work. Variability of these estimates is examined using the delta method and bootstrap resampling techniques. I am a member of the Behavioral Research Working Group and am involved in a number of collaborative projects in both the MACS and WIHS.

Statistics, Epiemiology of AIDS

Cox, C. Chu, H., Schneider, M.F. and Muñoz, A. (2007) Tutorial in biostatistics: parametric survival analysis and taxonomy of hazard functions for the generalized gamma distribution. Statistics in Medicine, (in press) DOI: 10.1002/sim.2836.

Plankey, M.W., Ostrow, D.G., Stall, R., Cox, C., Li, X., Peck, J.A. and Jacobson, L.P. (2007) The relationship between methamphetamine and popper use and risk of HIV seroconversion in the Multicenter AIDS Cohort Study. Journal of Acquired Immune Deficiency Syndromes 45, 85-92.

Cole, M.A., Margolick, J.B., Cox, C., Li, X., Selnes, O.A., Martin, E.M. Becker, J.T., Aronow, H.A., Cohen, B., Sacktor, N. and Miller, E.N. Longitudinally preserved psychomotor performance in long-term asymptomatic HIV-infected individuals. Neurology (in press).

Elder, A., Couderc, J.P., Gelein, R., Eberly, S., Cox, C., Xia, X., Zareba, W., Hopke, P., Watts, W., Kittelson, D., Frampton, M., Utell, M. and Oberdorster, G. (2007) Effects of on-road highway aerosol exposures on autonomic responses in aged, spontaneously hypertensive rats. Inhalation Toxicology 19, 1-12.

Frampton, M.W., Stewart, J.C., Oberdörster, G., Morrow, P.E., Chalupa, D., Pietropaoli, A.P., Frasier, L.M., Speers, D.M., Cox, C., Huang, L.-S. and Utell, M.J. (2006) Inhalation of ultrafine particles alters blood leukocyte expression of adhesion molecules in humans. Environmental Health Perspectives 114, 51-58.

Tanofsky-Kraff, M., Cohen, M.L., Yanovski, S.Z., Cox, C., Theim, K.R., Keil, M., Reynolds, J.C. and Yanovski, J.A. (2006) A prospective study of psychological predictors of body fat gain among children at high risk for adult obesity. Pediatrics 117, 1203-1209.

Saluja, G., Brenner, R.A., Trumble, A.C., Smith, G.S., Schroeder, T. and Cox, C. (2006) Swimming pool drownings among US residents aged 5-24 years: understanding racial/ethnic disparities. American Journal of Public Health 96, 728-733.

Parle-McDermott, A., Kirke, P.N., Mills, J.L., Molloy, A.M. Cox, C., O’Leary, V.B., Pangilinan, F., Conley, M., Cleary, L., Brody, L.C. and Scott, J.M. (2006) Confirmation of the R53Q polymorphism of the trifunctional C1-synthase enzyme as a maternal risk for neural tube defects in the Irish population. European Journal of Human Genetics 14, 768-772.

Davidson, P.W., Myers, G.J., Cox, C., Wilding, G.E., Shamlaye, C.F., Huang, L.S., Cernichiari, E., Sloane-Reeves, J., Palumbo, D. and Clarkson, T.W. (2006) Methylmercury and neurodevelopment: Longitudinal analysis of the Seychelles child development cohort. Neurotoxicology and Teratology 28, 529-535.

Cox, C. (2006) Model-based estimation of the attributable risk in case-control and cohort studies. Statistical Methods in Medical Research 15, 611-625.

Riudavets, M.A., Rubio, A., Cox, C., Rudow, G., Fowler, D. and Troncoso, J.C. (2006) The prevalence of Alzheimer neuropathologic lesions is similar in blacks and whites. The Journal of Neuropathology and Experimental Neurology 65, 1143-1148.

Huang, L.-S., Wang, H. and Cox, C. (2005) Assessing interaction effects in linear measurement error models. Applied Statistics 54, 21-30.

Cox, C. (2005) Limits of quantitation for laboratory assays. Applied Statistics 54, 63-76.

Huang, L.-S., Cox, C., Myers, G.J., Davidson, P.W., Cernichiari, E., Shamlaye, C.F., Sloane-Reeves, J. and Clarkson, T.W. (2005) Exploring nonlinear association between prenatal methylmercury exposure from fish consumption and child development: evaluation of the Seychelles Child Development Study nine-year data using semiparametric additive models. Environmental Research 97, 100-108.

Parle-McDermott, A., Mills, J.L. Kirke, P.N., Cox, C., Signore, C.C., Kirke, S., Molloy, A.N., O’Leary, V.B., Pangilinan, F.J., O’Herlihy, C. and Brody, L.C. (2005) MTHFD1 R653Q polymorphism is a maternal genetic risk factor for severe abruptio placentae. American Journal of Medical Genetics 132A, 365-368.

Signore, C., Mills, J.L., Cox, C. and Trumble, A.C. (2005) Effects of folic acid fortification on twin gestation rates. Obstetrics and Gynecology 105, 757-762.

Falsey, A.R., Hennessey, P.A., Formica, M.A., Cox, C. and Walsh, E.E. (2005) Respiratory syncytial virus infection in elderly and high-risk adults. New England Journal of Medicine 352, 1749-1759.

Mills, J.L., Druschel, C.M., Pangilinan, F., Pass, K., Cox, C., Seltzer, R.R., Conley, M.R. and Brody, L.C. (2005) Folate-related genes and omphalocele. American Journal of Medical Genetics, 136A, 8-11.

Parle-McDermott, A., Pangilinan, F., Mills, J.L., Signore, C., Molloy, A.M., Cotter, A., Conley, M., Cox, C., Kirke, P.N., Scott, J.M. and Brody, L.C. (2005) A polymorphism in the MTHFD1 gene increases a mother’s risk of having an unexplained second trimester pregnancy loss. Molecular Human Reproduction 11, 477-480.

Molloy, A.M., Mills, J.L., Cox, C., Daly, S.F., Conley, M., Brody, L.C., Kirke, P.N., Scott, J.M. and Ueland, P.M. (2005) Choline and homocysteine interrelations in umbilical and maternal plasma at delivery. American Journal of Clinical Nutrition 82, 836-842.