aCenter for Clinical Pharmacology, Department of Medicine, University of Pittsburgh, Pittsburgh and Departments of
bBiostatistics
cEnvironmental and Occupational Health
dEpidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
Correspondence and requests for reprints to Marjorie Romkes, Centre for Clinical Pharmacology, Department of Medicine, University of Pittsburgh, Suite 450, 100 Technology Drive, Pittsburgh, PA 15219, USA
Tel: +1 412 383 8885; fax: +1 412 648 1837;
e-mail: [email protected]
Sponsorship: This study was supported by grants R01 HD33016 and R01 HD36880 from the National Institute of Child Health and Human Development, National Institutes of Health to W. L. Bigbee and M. Romkes, respectively.
Received 29 July 2005 Accepted 19 September 2005