Reduced neutrophil count in people of African descent is due to a regulatory variant in the Duffy antigen receptor for chemokines gene.

Persistently low white blood cell count (WBC) and neutrophil count is a well-described phenomenon in persons of African ancestry, whose etiology remains unknown. We recently used admixture mapping to identify an approximately 1-megabase region on chromosome 1, where ancestry status (African or European) almost entirely accounted for the difference in WBC between African Americans and European Americans. To identify the specific genetic change responsible for this association, we analyzed genotype and phenotype data from 6,005 African Americans from the Jackson Heart Study (JHS), the Health, Aging and Body Composition (Health ABC) Study, and the Atherosclerosis Risk in Communities (ARIC) Study. We demonstrate that the causal variant must be at least 91% different in frequency between West Africans and European Americans. An excellent candidate is the Duffy Null polymorphism (SNP rs2814778 at chromosome 1q23.2), which is the only polymorphism in the region known to be so differentiated in frequency and is already known to protect against Plasmodium vivax malaria. We confirm that rs2814778 is predictive of WBC and neutrophil count in African Americans above beyond the previously described admixture association (P = 3.8 x 10(-5)), establishing a novel phenotype for this genetic variant.

Risk factors for Clostridium difficile nosocomial diarrhea in patients at the Michael E. Debakey Veterans Affairs Medical Center, Houston, Texas

Background. Clostridium difficile is the leading cause of hospital associated infectious diarrhea and colitis. About 3 million cases of Clostridium difficile diarrhea occur each year with an annual cost of $1 billion. ^ About 20% of patients acquire C. difficile during hospitalization. Infection with Clostridium difficile can result in serious complications, posing a threat to the patient's life. ^ Purpose. The aim of this research was to demonstrate the uniqueness in the characteristics of C. difficile positive nosocomial diarrhea cases compared with C. difficile negative nosocomial diarrhea controls admitted to a local hospital. ^ Methods. One hundred and ninety patients with a positive test and one hundred and ninety with a negative test for Clostridium difficile nosocomial diarrhea, selected from patients tested between January 1, 2002 and December 31, 2003, comprised the study population. Demographic and clinical data were collected from medical records. Logistic regression analyses were conducted to determine the associated odds between selected variables and the outcome of Clostridium difficile nosocomial diarrhea. ^ Results. For the antibiotic classes, cephalosporins (OR, 1.87; CI 95, 1.23 to 2.85), penicillins (OR, 1.57; CI 95, 1.04 to 2.37), fluoroquinolones (OR, 1.65; CI 95, 1.09 to 2.48) and antifungals (OR, 2.17; CI 95, 1.20 to 3.94), were significantly associated with Clostridium difficile nosocomial diarrhea Ceftazidime (OR, 1.95; CI 95, 1.25 to 3.03, p=0.003), gatifloxacin (OR, 1.97; CI 95, 1.31 to 2.97, p=0.001), clindamycin (OR, 3.13; CI 95, 1.99 to 4.93, p<0.001) and vancomycin (OR, 1.77; CI 95, 1.18 to 2.66, p=0.006, were also significantly associated with the disease. Vancomycin was not statistically significant when analyzed in a multivariable model. Other significantly associated drugs were, antacids, laxatives, narcotics and ranitidine. Prolong use of antibiotics and an increased number of comorbid conditions were also associated with C. difficile nosocomial diarrhea. ^ Conclusion. The etiology for C. difficile diarrhea is multifactorial. Exposure to antibiotics and other drugs, prolonged antibiotic usage, the presence and severity of comorbid conditions and prolonged hospital stay were shown to contribute to the development of the disease. It is imperative that any attempt to prevent the disease, or contain its spread, be done on several fronts. ^

Public service use by residents of Jackson Hinds Gardens before and after enrollment

Homelessness is associated with high use of public services such as health care and criminal justice services. Intervention designs to reverse homelessness have broadly fallen into two categories: either standard care which employs requisitely addressing the causes of homelessness, or housing first, which emphasizes provision of permanent housing without requisitely addressing the causes of homelessness. Multiple cities have recently commenced housing first interventions. Locally, Houston’s first housing first development is the Jackson Hinds Gardens project. The purpose of this study is to analyze the public service use of residents of housing first in Houston. Residents of Jackson Hinds Gardens who have been enrolled for at least 6 months were evaluated for public service use for an equal amount of time preceding and during their residence at Jackson Hinds. Resident interactions with county health services and criminal justice entities were determined by electronic database searches; these data were supplemented by life experience interview data. Service usage values pre- and post-enrollment at Jackson Hinds Gardens were compared by paired t-test analyses. We found that ER and inpatient usage decreased following enrollment in Jackson Hinds, although these reductions were not significant. In contrast, outpatient care and number of medications significantly increased following enrollment. These analyses inform on the effects of housing first in another major city, as well as informing the ethical considerations regarding housing first versus standard care. ^