Publications by authors named "Krista L Y Christensen"

Exposures to multiple chemicals may contribute to increased risk of similar adverse effects. Cumulative risk may be estimated using a hazard index (HI), the sum of individual hazard quotients (HQ, ratio of exposure to the reference value). We demonstrate the HI approach for five phthalates: di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DBP), diisobutyl phthalate (DiBP), diisononyl phthalate (DiNP), and butyl benzyl phthalate (BBP).

View Article and Find Full Text PDF

Bisphenol A (BPA) is used in the manufacture of a range of consumer products, and human biomonitoring studies suggest that exposure to BPA is nearly ubiquitous. We constructed and calibrated a simple pharmacokinetic model to predict urinary concentrations of BPA based on a known initial dose. This descriptive (rather than physiologically based) model has three compartments: "stomach/liver," "blood," and "bladder.

View Article and Find Full Text PDF

Human biomonitoring studies measuring phthalate metabolites in urine have shown widespread exposure to phthalates in the general population. Diet is thought to be a principle route of exposure to many phthalates. Therefore, we studied urinary phthalate metabolite patterns over a period of strict fasting and additionally recorded personal activity patterns with a diary to investigate non-dietary routes of exposure.

View Article and Find Full Text PDF

Human exposure to phthalates and bisphenol A (BPA) can be assessed through urinary biomonitoring, but methods to infer daily intakes assume that spot sample concentrations are comparable to daily average concentrations. We evaluate this assumption using human biomonitoring data from Germany and the United States (US). The German data comprised three regional studies with spot samples and one with full-day samples analyzed for phthalate metabolites.

View Article and Find Full Text PDF

Background: Progressive multifocal leukoencephalopathy (PML) is a neurological disease most often seen among immunosuppressed patients. The incidence of PML increased with an increasing incidence of HIV/AIDS. We describe recent trends and the epidemiology of PML-associated death in the era of highly active antiretroviral therapy (HAART).

View Article and Find Full Text PDF

Background: Infectious diseases (IDs) cause widespread morbidity and mortality. We describe the epidemiology of ID hospitalizations in the United States with use of a nationally representative database.

Methods: First-listed ID hospitalizations in the United States were analyzed using the Nationwide Inpatient Sample for 1998-2006.

View Article and Find Full Text PDF