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OBJECTIVE:: Adjusted costs of mechanical ventilation (MV) are $1,500 per patient-day. We compared the prevalence, characteristics, and outcomes of MV <96 hrs (MV<96) and prolonged acute MV (PAMV) of >/=96 hrs' duration in a representative sample of U.S. hospital discharges. DESIGN:: A multicenter cross-sectional study. SETTING:: Nationally representative sample of U.S. hospital discharges. PATIENTS:: Adult hospital discharges were identified from the 2003 Nationwide Inpatient Sample, Healthcare Cost and Utilization Project from the Agency for Healthcare Research and Quality (AHRQ). PAMV was based on the presence of ICD-9 code 96.72, and MV <96 hrs based on ICD-9 codes 96.70 and 96.71. INTERVENTIONS:: None. MEASUREMENTS AND MAIN RESULTS:: Of 31,340,578 discharges for adults (>/=18 yrs), 2.4% had any MV, of which 469,168 (61%) had MV<96, and 294,333 (39%) had PAMV. Patient demographics were similar for MV<96 and PAMV. With the exception of acute myocardial infarction and chronic and end-stage renal disease without dialysis, the prevalence of coexisting conditions was higher in the PAMV group. Median length of stay (17 vs. 6 days) and hospital costs ($40,903 vs. $13,434) also were higher with PAMV vs. MV<96. Although Agency for Healthcare Research and Quality disease severity and mortality probability were higher in the PAMV than MV<96 group, actual mortality was similar between the two groups (34% vs. 35%). CONCLUSIONS:: There were nearly 300,000 PAMV discharges in the United States in 2003 at an annual aggregated hospital cost of >$16 billion, or nearly two thirds of the cost for all of the MV discharges. Despite a higher predicted mortality, patients requiring PAMV had the same likelihood of being discharged alive as those on shorter-term MV. These analyses will help inform health care decision-making and resource planning in the face of an aging population. [ABSTRACT FROM AUTHOR]

Objectives: Training-related injury is a threat to military health and readiness. Prevalence of potential risk factors for training-related injury can change with U.S. Army recruitment goals and may influence basic combat training (BCT) injury rates. This article describes challenges of using administrative data to identify a trainee cohort and describes demographic and training characteristics across the five BCT locations., Methods: Data from the Total Army Injury and Health Outcomes Database were used to identify a U.S. Army-wide cohort of first-time trainees from January 1, 2002 to September 30, 2007 and describe its characteristics., Results: The cohort includes 368,102 first-time trainees. The annual number starting BCT increased from 52,187 in 2002 to 68,808 in 2004. The proportion of males increased from 81.57% in 2003 to 83.84% in 2007. Mean (SD) age increased from 20.67 (3.55) years in 2002 to 20.94 (3.65) years in 2007. Mean (SD) body mass index increased from 24.53 (3.56) kg/m(2) in 2002 to 24.94 (3.84) kg/m(2) in 2006. Other characteristics fluctuated by year, including proportions of race/ethnicity, accession waivers, and confirmed graduates., Conclusions: Fluctuations in trainee characteristics warrant further analysis of potential influence on BCT injury rates. For research uses, careful acquisition of administrative data is needed., (Reprint & Copyright © 2014 Association of Military Surgeons of the U.S.)

To evaluate the potential for long-term or delayed onset health effects, we extended a previous cohort study of disability separation from the army associated with vaccination against anthrax. Analyses included stratified Cox proportional hazards and multiple logistic regression models. Forty-one percent of 1,001,546 soldiers received at least one anthrax vaccination; 5.21% were evaluated for disability. No consistent patterns or statistically significant differences in risk of disability evaluation, disability determination, or reason for disability were associated with anthrax vaccination. There was a dose-related trend in risk of disability for soldiers with 2 years' service, limited to those entering service in 2000 or later. Divergent patterns in risk suggest confounding by temporal or occupational risks of disability., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Outside-the-boot parachute ankle braces (PABs) worn during US Army paratrooper training have been shown to reduce the risk of severe ankle injuries. In spite of evidence to the contrary, anecdotal reports continue to suggest increases in risk of other types of injury, and the cost of obtaining and periodically replacing the PAB has been used to justify its discontinued use. The authors identified inpatient and outpatient treatment for injuries during US Army paratrooper training. Those undergoing training during two periods when PAB use was mandated had 40% lower risks of ankle injury (brace I, RR=0.60 (95% CI 0.47 to 0.75); brace II, RR=0.62 (95% CI 0.49 to 0.78)), with no difference in risks of other types of injury. There were no differences in risk of ankle injury during periods when brace use was not mandated. The PAB is safe, effective and cost effective.

Introduction: An epidemiological study was conducted of a perfluorononanoic acid (PFNA) surfactant blend, to investigate whether clinical differences were apparent between employees who were potentially exposed to the surfactant and those who were not exposed. The surfactant blend, which is related to other previously studied perfluorinated materials, is used in the production of some high-performance polymers., Methods: All 630 individuals employed at a polymer production facility using PFNA (CAS No 72968-38-8) at any time between 1 January 1989 and 1 July 2003 were included in the cohort. Plausibly related laboratory test results were abstracted from annual medical examination records, including liver enzyme function and blood lipids. Detailed work histories, available for all employees, provided the basis for determining exposure category. Thirty two clinical parameters were evaluated by exposure level at five points in time, determined to reflect changes in possible exposure intensity, as well as greatest number of records available. Annual cross-sectional analyses and longitudinal analyses that accounted for multiple measurements per person were conducted separately for men and women, by exposure groups., Results: Differences by exposure group for all laboratory measures, adjusted for age and body mass index, were small and not clinically significant. Although some statistically significant pair-wise differences were observed, these observations were not consistent between men and women, or over the five analysis windows. For the seven outcome variables (liver enzymes and blood lipids) examined in separate longitudinal models, no significant increase or decrease was observed by unit increase in cumulative exposure intensity score., Conclusion: This is the first epidemiological study investigating the possible health effects in humans associated with exposure to PFNA blend. Based on laboratory measures assessed over more than a decade, no adverse clinical effects were detected from occupational exposure to PFNA blend.

Objectives: We conducted a mortality study of two German chromate production facilities and evaluated possible dose-response relationships between hexavalent chromium exposure and lung cancer., Methods: Mortality was followed-up through 1998 and limited to those employed since each plant converted to a no-lime production process. More than 12,000 urinalysis results of chromium levels were available, as was smoking information., Results: All-cause mortality indicated a healthy worker effect (standardized mortality ratio [SMR] = 0.80, 95% confidence interval [CI] = 0.67-0.96); however, lung cancers appeared to be increased (SMR = 1.48, 95% CI = 0.93-2.25). No clear dose-response was found in stratified analyses by duration of employment and time since hire. On the basis of urinary chromium data, lung cancer risk was elevated only in the highest exposure group (SMR = 2.09, 95% CI = 1.08-3.65)., Conclusions: These data suggest a possible threshold effect of occupational hexavalent chromium exposure on lung cancer.

Objective: Although numerous studies have reported an elevated lung cancer risk among chromium chemical production employees, few studies have focused on employees hired after major process changes and enhanced industrial hygiene controls were implemented., Methods: This study examines the mortality experience of two post-change cohorts of chromate production employees constituting the current US chromium chemical industry., Results: Mortality among chromium chemical workers generally was lower than expected on the basis of national and state-specific referent populations. Lung cancer mortality was 16% lower than expected, with only three lung cancer deaths (3.59 expected)., Conclusion: The absence of an elevated lung cancer risk may be a favorable reflection of the post-change environment. However, longer follow-up allowing an appropriate latency for the entire cohort will be needed to confirm this conclusion.

Some have suggested a threshold mechanism for the carcinogenicity of exposure to hexavalent chromium, Cr(VI). We evaluated the nature of the exposure-response relationship between occupational exposure to Cr(VI) and respiratory cancer based on results of two recently published epidemiological cohort studies. The combined cohort comprised a total of 2,849 workers employed at two U.S. chromate production plants between 1940 and 1974. Standardized mortality ratios (SMRs) for lung cancer in relation to cumulative Cr(VI) exposure categories were reported using regional mortality rates. Linear additive and multiplicative relative risk regression models were fit to the SMRs of the individual and combined studies. Both models fit the data from the individual studies reasonably well; however, the fit was somewhat less adequate for the pooled data. Meta-analysis of the slope estimates obtained from the multiplicative relative risk model showed substantial heterogeneity between the two epidemiological studies. In conclusion, these data indicate that a linear dose response describes the relationship between Cr(VI) and lung cancer reasonably well, and therefore these analyses do not necessarily support the threshold hypothesis for the lung carcinogenicity of Cr(VI). However, these results must be interpreted with recognition of the limitations of the use of epidemiological data in the evaluation of nonlinear exposure-response patterns.

Aims: To assess mortality in 1997 among 493 former workers of a US chromate production plant employed for at least one year between 1940 and 1972., Methods: Cohort members were followed for mortality to 31 December 1997. Standardised mortality ratios (SMRs) were calculated for selected cause specific categories of death including lung cancer. Lung cancer mortality was investigated further by calculation of SMRs stratified by year of hire, duration of employment, time since hire, and categories of cumulative exposure to Cr(VI)., Results: Including 51 deaths due to lung cancer, 303 deaths occurred. SMRs were significantly increased for all causes combined (SMR = 129), all cancers combined (SMR = 155), and lung cancer (SMR = 241). A trend test showed a strong relation between lung cancer mortality and cumulative hexavalent exposure. Lung cancer mortality was increased for the highest cumulative exposure categories (> or =1.05 to <2.70 mg/m(3)-years, SMR = 365; > or =2.70 to 23 mg/m(3)-years, SMR = 463), but not for the first three exposure groups. Significantly increased SMRs were also found for year of hire before 1960, 20 or more years of exposed employment, and latency of 20 or more years., Conclusions: The finding of an increased risk of lung cancer mortality associated with Cr(VI) exposure is consistent with previous reports. Stratified analysis of lung cancer mortality by cumulative exposure suggests a possible threshold effect, as risk is significantly increased only at exposure levels over 1.05 mg/m(3)-years. Though a threshold is consistent with published toxicological evidence, this finding must be interpreted cautiously because the data are also consistent with a linear dose response.

In response to concerns about occupational and environmental exposures, and a perceived cluster of amyotrophic lateral sclerosis (ALS) in the community, the mortality experience among 31,811 civilian employees who worked for at least 1 year between 1981 and 2000 at Kelly Air Force Base, Texas was ascertained. A total of 3264 deaths occurred through October 31, 2001. Overall, significant deficits in mortality were observed for all causes of death and all cancers combined. An excess of breast cancer [standardized mortality ratio (SMR) = 216; 95% confidence interval (CI) = 128-341] among blue-collar women was identified, and remained elevated after adjusting for race and ethnicity [rate ratio (RR) = 2.83; 95% CI = 1.50-5.34]. Mortality from motor neuron disease, which includes ALS deaths, was not increased overall (SMR = 0.98; 95% CI = 0.52-1.68), and was lower among blue-collar employees and higher among white-collar employees than expected, based on small numbers. Overall, mortality patterns indicated a healthy worker population and no large increased mortality associated with employment at Kelly Air Force Base.

Objectives: To update and assess mortality from neoplasms to 31 December 1995 among 10 109 men employed in a job exposed to vinyl chloride for at least 1 year between 1942 and 1972 at any of 37 North American factories. Previous analyses indicated associations between employment in vinyl production and increased mortality risk from cancers of the liver and biliary tract, due to increased mortality from angiosarcoma of the liver, and brain cancer., Methods: Standardised mortality ratio (SMR) analyses, overall and stratified by several work related variables, were conducted with United States and state reference rates. Cox's proportional hazards models and stratified log rank tests were used to further assess occupational factors., Results: 895 of 3191 deaths (28%) were from malignant neoplasms, 505 since the previous update to the end of 1982. Mortality from all causes showed a deficit (SMR 83, 95% confidence interval (95% CI) 80 to 86), whereas mortality from all cancers combined was similar to state referent rates. Mortality from cancers of the liver and biliary tract was clearly increased (SMR 359, 95% CI 284 to 446). Modest excesses of brain cancer (SMR 142, 95% CI 100 to 197) and cancer of connective and soft tissue (SMR 270, 95% CI 139 to 472) were found. Stratified SMR and Cox's proportional hazard analyses supported associations with age at first exposure, duration of exposure, and year of first exposure for cancers of the liver and soft tissues, but not the brain., Conclusions: Excess mortality risk from cancer of the liver and biliary tract, largely due to angiosarcoma, continues. Risk of mortality from brain cancer has attenuated, but its relation with exposure to vinyl chloride remains unclear. A potentially work related excess of deaths from cancer of connective and soft tissue was found for the first time, but was based on few cancers of assorted histology.

Associations between selected sites of musculoskeletal discomfort and ergonomic characteristics of the video display terminal (VDT) workstation were assessed in analyses controlling for demographic, psychosocial stress, and VDT use factors in 273 VDT users from a large administrative department. Significant associations with wrist/hand discomfort were seen for female gender; working 7+ hours at a VDT; low job satisfaction; poor keyboard position; use of new, adjustable furniture; and layout of the workstation. Significantly increased odds ratios for neck/shoulder discomfort were observed for 7+ hours at a VDT, less than complete job control, older age (40 to 49 years), and never/infrequent breaks. Lower back discomfort was related marginally to working 7+ hours at a VDT. These results demonstrate that some characteristics of VDT workstations, after accounting for psychosocial stress, can be correlated with musculoskeletal discomfort.

Objectives: This study investigated sources of self reported psychological stress among international business travellers at the World Bank, following up on a previous study showing that travellers submitted more insurance claims for psychological disorders. Hypotheses were that work, personal, family, and health concerns, as well as time zone travel, contribute to travel stress., Methods: A travel survey was developed from focus groups and consisted of questions about these potential sources of travel stress. Surveys were sent to a random sample of staff, stratified by number of travel missions, age range, and sex. Canonical correlation analyses estimated the association between key survey items on sources of stress and two measures of travel stress., Results: 498 staff completed the survey. More than a third reported high to very high travel stress. Correlations between predictors and travel stress showed that social and emotional concerns (such as impact of travel on family and sense of isolation) contributed the most to such stress, followed by health concerns, and workload upon return from travel. Surprisingly, time zone travel did not contribute to the self reported stress of these travellers. There were few modifiers of stress, although respondents suggested that a day of rest after travel and reduced workloads would help., Conclusions: The current study confirms clinical impressions about several correlates of travel stress. Similar research with travellers in other organisations could help to determine whether the findings from this study are valid and what measures can be taken to reduce the psychological health risks to travellers.

In evaluating the efficacy of physician-delivered counseling interventions for health behavior changes such as smoking cessation, a major challenge is determining the degree to which interventions are implemented by physicians. The Patient Exit Interview (PEI; J. Ockene et al., 1991) is a brief measure of a patient's perception of the content and quantity of smoking cessation intervention received from his or her physician. One hundred eight current smokers seen in a primary care clinic completed a PEI following their physician visit. Participants were 45% male, 95% Caucasian, with a mean age of 42 years and an average of 22 years of smoking. The PEI correlated well with a criterion measure of an audiotape assessment of the physician-patient interaction (r = .67, p < .001). When discrepancy occurred, in general it was due to patients' over-reporting of intervention as compared with the criterion measure. Implications and limitations of these findings are discussed.

Background: We examined the effect of a 3-hr training program on physicians' lipid intervention knowledge, attitudes, and skills. The program teaches physicians skills to conduct a brief dietary risk assessment and provide patient-centered counseling to enable patients with elevated lipids to change their dietary patterns., Method: The training is part of a randomized trial of lipid-lowering interventions, the Worcester Area Trial for Counseling in Hyperlipidemia. Primary care internists practicing in a health maintenance organization (HMO) were assessed, before and after training using questionnaires and audiotapes to document changes in knowledge about diet, attitudes about intervention, reported nutrition intervention practices, and counseling and assessment skills. Physicians also rated the value that they thought the training program had to them., Results: After completion of the program the physicians' use of dietary counseling steps, as assessed by blinded evaluation of audiotaped physician-patient interactions, significantly increased (mean pre = 5.4, mean post = 9.2; t = 9.9; P < or = 0.001). In this regard, there were instances in the use of 7 of the 14 specific counseling steps. Physicians also demonstrated increases in self-perceived preparedness as measured by a 5-point scale (mean pre = 3.2, mean post = 4.0; t = 4.25; P < 0.001), confidence in having an effect (mean pre = 3.3, mean post = 3.9; t = 3.16; P < 0.01), perception that materials were available to aid intervention (mean pre = 2.7, mean post = 4.0; t = 5.29; P < 0.001), and perception that they have access to a nutritionist (mean pre = 3.5, mean post = 4.0; t = 2.63; P < 0.01). They rated the value of the program between very good and excellent., Conclusion: Results of this 3-hr educational program indicate that physicians in an HMO are responsive to the teaching of specialized skills deemed important for promoting health behavior change in their patients.

Background: Systemic hypotension, at times transient while in other instances more prolonged, is common among patients with myocardial infarction (MI). It also is a characteristic feature for patients experiencing either advanced congestive heart failure or cardiogenic shock. In this group of patients, thrombolytic therapy has failed to exert. favorable impact on their high in-hospital mortality. Although it has been postulated that the success of thrombolytic therapy is directly linked to systemic blood pressure' there is little information available in human subjects. Methods and Results: In a University of Massachusetts Thrombolysis Data Bank Study, 127 patients with MI who were given intravenous thrombolytic therapy (tPA or streptokinase) within 6 hours from symptom onset (4.2 +/- 1.5 hours) had serial systemic blood pressure measurements (at the time of hospital arrival, treatment initiation, and every 30 minutes during the thrombolytic infusion) and underwent coronary angiography within 120 minutes of treatment initiation. All patients received intravenous heparin and oral aspirin. By univariate analysis, disastolic blood pressure below 80 mmHg at the time of treatment initiation was associated with a reduced angiographic coronary perfusion grade [Thrombolysis in Myocardial Infarction (TIMI) flow grade; p + 0.02]. A correlation analysis of tPA-treated patients indicated that a greater maximum change in diastolic blood pressure during treatment correlated inversely with coronary perfusion (r +.24, p < 0.05). By multivariate regression analysis, however, only shorter time to treatment (p + 0.001) and thrombolysis with tPA (p + 0.02) were independent predictors of coronary arterial perfusion grade. Conclusion: Systemic blood pressure (and presumably proximal coronary arterial perfusion pressure) in the ranges investigated in this study is not an independent predictor of coronary reperfusion following intravenous thrombolytic therapy with either tPA or streptokinase. It seems likely, therefore, that properties intrinsic to the ruptured plaque and occlusive thrombus, and potentially the local metabolic environment, either alone or acting synergistically with perfusion pressure, are determinants of thrombolytic success. Further investigation of factors influencing the efficacy of thrombolysis should be undertaken.