Low level of the plasma sphingolipid, glucosylceramide, is associated with thrombotic diseases.

BACKGROUND: One previous pilot study suggested the association of low plasma glucosylceramide (GlcCer) levels with venous thrombosis (VTE) risk. OBJECTIVE: We aimed to confirm and evaluate the association of low plasma GlcCer levels with VTE and myocardial infarction (MI) occurrence, respectively. PATIENTS AND METHODS: We evaluated the association of GlcCer in two independent case-control studies of Caucasian VTE populations (N = 210 and 636) and one case-control study of Caucasian MI patients (N = 345). RESULT: Plasma GlcCer levels in VTE patients were lower compared to controls in two independent VTE populations (5.0 vs 5.8 µg/mL, p = 0.003 for the Scripps registry, and 5.6 vs 6.0 µg/mL, p = 0.001 for the Valencia registry, respectively). A low plasma GlcCer level (below 10th percentile of controls) was associated with increased VTE occurrence [odds ratio (OR) = 3.7 (95%CI, 1.8-7.9) for Scripps registry and OR = 2.1 (95%CI, 1.3-3.3) for Valencia registry, respectively). For the MI study, the median GlcCer plasma level was lower in MI patients than in controls (4.3 vs 5.6 µg/mL, p<0.001), and a low level of GlcCer (below 10th percentile of control) was associated with higher MI occurrence [OR = 7.7, (95%CI, 4.3-13.8)]. CONCLUSION: Lower concentration of GlcCer was associated with VTE occurrence in two independent studies and also with MI occurrence in one study.

High factor VIII, von Willebrand factor, and fibrinogen levels and risk of venous thromboembolism in blacks and whites.

Venous thromboembolism (VTE) affects more than 300,000 people in the United States each year. However, it has been estimated that current diagnostic testing fails to identify prothrombotic risk in 50% of VTE patients. This article examines the relationship between levels of the pro-coagulant proteins factor VIII (FVIII), von Willebrand factor (VWF), and fibrinogen and risk of VTE in order to assess the impact of these novel risk factors. Data were collected from patients enrolled in the matched case-control Genetic Attributes and Thrombosis Epidemiology study. Crude and adjusted conditional logistic regression models were used to assess the impact of FVIII, VWF, and fibrinogen on risk of VTE. Before adjustment for independent predictors of VTE risk, high levels of FVIII, VWF, and fibrinogen were significantly associated with increased risk of VTE in both Blacks and Whites. After adjustment for ABO type, factor VII levels, hypertension, renal disease, recent surgery, diabetes, annual household income, alcohol use, and the other proteins of interest (FVIII, VWF, and/or fibrinogen), high FVIII and VWF levels were associated with increased risk of VTE in Blacks (OR: 1.97 [1.01-3.84] and 3.39 [1.58-7.27], respectively). High FVIII only was significantly associated with risk of VTE in Whites (OR: 2.35 [1.16-4.75]). Future research into the inclusion of these protein levels in risk models for VTE could help identify persons at highest risk.

Occupational exposure to metribuzin and the incidence of cancer in the Agricultural Health Study.

PURPOSE: Little is known about the potential carcinogenicity of the triazinone herbicide metribuzin. We evaluated the association between metribuzin use and cancer risk in the Agricultural Health Study, a prospective cohort study of licensed pesticide applicators in Iowa and North Carolina. METHODS: Applicators (N=23,072) provided information on metribuzin use on a self-administered questionnaire at enrollment (1993-1997). Among metribuzin users (n=8,504), there were 554 incident cancer cases. We used multivariable Poisson regression to evaluate potential associations between metribuzin use and cancer incidence by using two quantitative exposure metrics, lifetime days and intensity-weighted lifetime days. RESULTS: Using intensity-weighted lifetime days, the rate ratio (RR) and 95% confidence interval (CI) for the highest exposed tertile for lymphohematopoietic malignancies were 2.09 (95% CI: 0.99-4.29), p trend=0.02 and 2.42 (95% CI: 0.82-7.19), p trend=0.08 for leukemia. For non-Hodgkin lymphoma, the RR was 2.64 (95% CI: 0.76-9.11), p trend=0.13 for lifetime days and 2.52 (95% CI: 0.66-9.59), p trend=0.13 for intensity-weighted lifetime days. Patterns of association were similar for both exposure metrics, but associations were generally weaker than for intensity-weighted days. CONCLUSIONS: The results from this study suggest a potential association between metribuzin use and certain lymphohematopoietic malignancies; however, having not been observed previously, caution should be used in interpretation.

Risk factors for incident herpes simplex type 2 virus infection among women attending a sexually transmitted disease clinic.

OBJECTIVES: To estimate the incidence of herpes simplex type 2 virus (HSV-2) infection, to identify risk factors for its acquisition, and to assess the protective effect of condoms. STUDY DESIGN: Prospective study of 293 HSV-2 seronegative women, aged 18 to 35 years, attending a sexually transmitted disease clinic in Alabama from 1992 to 1995. RESULTS: Incidence of HSV-2 infection was 20.5 per 100 woman-years [95% confidence interval (CI), 13.1-30.5]. Young women (18-20 years) had a significantly higher risk of incident HSV-2 infection [adjusted hazard ratio (HR), 2.8; 95% CI, 1.3-6.4] than older women. Women diagnosed with prevalent or incident bacterial vaginosis had a higher incidence of HSV-2 infection than those who were not so diagnosed (adjusted HR, 2.4; 95% CI, 1.1-5.6). No significant protective effect was observed for consistent (100%) condom use without breakage and slippage against HSV-2 acquisition (adjusted HR, 0.8; 95% CI, 0.2-2.3). CONCLUSION: Acquisition of HSV-2 infection among study participants was higher than previous estimates for adult female sexually transmitted disease clinic attendees, and no protective effect for condoms was demonstrated. The high incidence of HSV-2 infection with its potential for adverse health consequences emphasizes the need for better prevention strategies.

Relation of adult-onset asthma to coronary heart disease and stroke.

Asthma was associated with atherosclerotic disease in several studies, with evidence that this association may be limited to women. However, most previous studies failed to account for the heterogeneity of asthma subtypes. We previously reported increased carotid intima-medial thickness in women with adult-onset asthma. In this study, the association of adult- and child-onset asthma with incident coronary heart disease (CHD) and stroke were examined. Subjects were classified according to self-report of physician-diagnosed asthma and age of asthma onset. Cox proportional hazards models were used to test the association of adult- and child-onset asthma with incident CHD and stroke, testing for gender interaction. Subanalysis was also performed using only never smokers. Women with adult-onset asthma experienced a 2-fold increase in incident CHD and stroke that was independent of other risk factors, including smoking, body mass index, and physical activity, and persisted when analysis was restricted to never smokers. No significant association was found in women with child-onset asthma or in men. In conclusion, adult-onset asthma may be a significant risk factor for CHD and stroke in women, but not men.

Use of state cancer surveillance data to estimate the cancer burden in disaster-affected areas--Hurricane Katrina, 2005.

PURPOSE: The objective of this study was to estimate the burden of cancer in counties affected by Hurricane Katrina using population-based cancer registry data, and to discuss issues related to cancer patients who have been displaced by disasters. METHODS: The cancer burden was assessed in 75 counties in Louisiana, Alabama, and Mississippi that were designated by the Federal Emergency Management Agency as eligible for individual and public assistance. Data from the National Program of Cancer Registries were used to determine three-year average annual age-adjusted incidence rates and case counts during the diagnosis years 2000-2002 for Louisiana and Alabama. Expected rates and counts for the most-affected counties in Mississippi were estimated by direct, age-specific calculation using the 2000-2002 county level populations and the site-, sex-, race-, and age-specific cancer incidence rates for Louisiana. RESULTS: An estimated 23,549 persons with a new diagnosis of cancer in the past year resided in the disaster-affected counties. Fifty-eight percent of the cases were cancers of the lung/bronchus, colon/rectum, female breast, and prostate. Eleven of the top 15 cancer sites by sex and black/white race in disaster counties had >50% of cases diagnosed at the regional or distant stage. CONCLUSIONS: Sizable populations of persons with a recent cancer diagnosis were potentially displaced by Hurricane Katrina. Cancer patients required special attention to access records in order to confirm diagnosis and staging, minimize disruption in treatment, and ensure coverage of care. Cancer registry data can be used to provide disaster planners and clinicians with estimates of the number of cancer patients, many of whom may be undergoing active treatment.

Access to pediatric cancer care by age, race, and diagnosis, and outcomes of cancer treatment in pediatric and adolescent patients in the state of Georgia.

PURPOSE: There have been concerns among pediatric oncologists that adolescent and minority patients are not getting adequate access to care. This study examines access to cancer care and survival outcomes based on age, race, and type of cancer in patients in Georgia. PATIENTS AND METHODS: We performed a retrospective review of 1,751 cancer patients aged 0 to 19 years, diagnosed between 1998 and 2002, in the Georgia Comprehensive Cancer Registry, which identified patients who were treated at one of five Georgia pediatric cancer centers (Children's Oncology Group [COG] members) at any point in their treatment. Data were further analyzed for age at diagnosis, race, county of residence, and 5-year survival. RESULTS: Eighty-seven percent of patients aged 0 to 14 years and 36% of those aged 15 to 19 years were treated at a COG institution. Twenty-five percent of all patients were of African descent, with 75.4% of black versus 70.3% of white patients (age 0 to 19 years) treated at a COG institution (P < .01); 97.1% of other minorities were treated at a COG institution (P < .05). The 5-year actuarial survival rates for more pediatric-specific cancers were significantly lower in all leukemias (75.1% v 46.4%; P = .0015), and acute lymphoblastic leukemia specifically (86.3% v 53.3%; P < .05) for patients not treated at a COG institution. Actuarial survival rates were much lower for blacks than whites in all cancers as a whole (70% v 82%; P < .001) and for many specific subtypes. CONCLUSION: Adolescent-aged patients are less likely to be referred to a COG institution, potentially exposing them to worse outcomes in some cancer subtypes. Reassuringly, minority populations are receiving adequate access to pediatric cancer care; unfortunately their survival rates are lower.

Condom use and risk of gonorrhea and Chlamydia: a systematic review of design and measurement factors assessed in epidemiologic studies.

BACKGROUND: Studies of condom use to reduce risk of most sexually transmitted infection provide inconsistent results. This inconsistency is often attributed to methodologic limitations yet has not been assessed systematically. OBJECTIVES: The objectives of this study were to review studies of condom use and risk of gonorrhea and chlamydia, and to evaluate the importance of 4 key design and measurement factors on condom effectiveness estimates. DESIGN: We reviewed studies published 1966-2004 to assess risk reduction for gonorrhea and/or chlamydia associated with male condom use. RESULTS: Of 45 studies identified, most found reduced risk of infection associated with condom use. All studies reviewed had methodologic limitations: only 28 (62%) distinguished consistent from inconsistent use; 2 (4%) reported on correct use or use problems; 13 (29%) distinguished incident from prevalent infection; and one (2%) included a population with documented exposure to infection. Eight of 10 studies with 2 or more of these attributes reported statistically significant protective effects for condom use versus 15 of 35 studies with zero or one attribute (80% vs. 43%, P = 0.04). CONCLUSIONS: Condom use was associated with reduced risk of gonorrhea and chlamydia in men and women in most studies, despite methodologic limitations that likely underestimate condom effectiveness. Epidemiologic studies that better address these factors are needed to provide more accurate assessment of condom effectiveness.

Application of the case-crossover design to reduce unmeasured confounding in studies of condom effectiveness.

This analysis examined how unmeasured confounding affects estimates of the effectiveness of condoms in preventing sexually transmitted infections. Data were analyzed from a prospective cohort study of 1,122 female sexually transmitted disease clinic patients in Alabama (1992-1995), wherein participants were evaluated for sexually transmitted infections at six 1-month intervals. Associations between condom use and incident gonorrhea and chlamydia infection were compared between case-crossover and cohort analyses. In a case-crossover analysis of 228 follow-up visits ending in gonorrhea/chlamydia ("case intervals") and 743 self-matched follow-up visits not ending in gonorrhea/chlamydia ("noncase intervals") (183 women), consistent condom use without breakage or slippage was associated with significantly reduced risk of infection relative to nonuse (adjusted risk odds ratio = 0.49, 95% confidence interval: 0.26, 0.92). Conversely, a cohort analysis of 245 case intervals and 3,896 noncase intervals (919 women) revealed no significant reduction in infection risk from consistent use of condoms (adjusted risk odds ratio = 0.79, 95% confidence interval: 0.53, 1.17). Dose-response relations between the number of unprotected sex acts and infection were stronger in the case-crossover analysis (p for trend = 0.009) than in the cohort analysis (p for trend = 0.18). These findings suggest that epidemiologic studies confounded by unmeasured differences between condom users and nonusers underestimate condom effectiveness against these infections. The case-crossover method provides an additional technique for reducing unmeasured confounding in studies of condom effectiveness.

Condom effectiveness for reducing transmission of gonorrhea and chlamydia: the importance of assessing partner infection status.

This analysis examined the importance of differential exposure to infected partners in epidemiologic studies of latex condom effectiveness for prevention of sexually transmitted infections. Cross-sectional, enrollment visit data were analyzed from Project RESPECT, a trial of counseling interventions conducted at five publicly funded US sexually transmitted disease clinics between 1993 and 1997. The association between consistent condom use in the previous 3 months and prevalent gonorrhea and chlamydia (Gc/Ct) was compared between participants known to have infected partners and participants whose partner infection status was unknown. Among 429 participants with known Gc/Ct exposure, consistent condom use was associated with a significant reduction in prevalent gonorrhea and chlamydia (30% vs. 43%; adjusted prevalence odds ratio = 0.42, 95% confidence interval: 0.18, 0.99). Among 4,314 participants with unknown Gc/Ct exposure, consistent condom use was associated with a lower reduction in prevalent gonorrhea and chlamydia (24% vs. 25%; adjusted prevalence odds ratio = 0.82, 95% confidence interval: 0.66, 1.01). The number of unprotected sex acts was significantly associated with infection when exposure was known (p for trend < 0.01) but not when exposure was unknown (p for trend = 0.73). Restricting analyses to participants with known exposure to infected partners provides a feasible and efficient mechanism for reducing confounding from differential exposure to infected partners in condom effectiveness studies.