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Bone mineral density (BMD) and geometric bone measures are individually associated with prevalent osteoporotic fractures. Whether an aggregate of these measures would better associate with fractures has not been examined. We examined relationships between self-reported fractures and selected bone measures acquired by quantitative computerized tomography (QCT), a composite bone score, and QCT-acquired dual-energy X-ray absorptiometry-like total femur BMD in 2110 men and 2682 women in the Age, Gene/Environment Susceptibility-Reykjavik Study. The combined bone score was generated by summing gender-specific Z-scores for 4 QCT measures: vertebral trabecular BMD, femur neck cortical thickness, femur neck trabecular BMD, and femur neck minimal cross-sectional area. Except for the latter measure, lower scores for QCT measures, singly and combined, showed positive (p&nbsp

Background: Few studies have used SEER-Medicare data to describe recurrence of breast cancer after primary treatment for U.S. women. Methods: We used SEER-Medicare data to estimate the annual hazard rate (HR) of recurrence for women with breast cancer between 1991 and 1997 with 10 years of follow-up. The Kaplan–Meier method was used to derive the HR. Multivariate Cox proportional hazards model was used to estimate the relative hazard of the recurrence-associated prognostic factors. Results: Of 20,027 women, 36.8% had recurrence within 10 years, with most of these recurrences (81.9%) occurring within 5 years after diagnosis. Women with stage III cancer showed the highest HR peak and largest magnitude than women with stage I or II disease (both P < 0.01) within the first 5 years. Women with negative tumor hormone receptor status had a higher peak hazard of developing recurrence within the first 5 years (P < 0.01), but the hazards were remarkably lower beyond 5 years of follow-up than in women with positive or unknown hormone receptor status (P > 0.05). Women with poorly differentiated histologic grade tumors showed higher HR in the first 5 years than women with other grades after primary treatment (both P < 0.01). The increased risk of recurrence of breast cancer was associated with advanced stage, moderate and poorly differently grades, and negative hormone receptor status (all P < 0.01). Conclusion: The HRs of the recurrence are dynamic over 10 years and are markedly determined by prognostic factors at diagnosis. Impact: Our study suggests that the optimal follow-up may differ among women. Cancer Epidemiol Biomarkers Prev; 21(5); 800–9. ©2012 AACR.

OBJECTIVE The objectives of the current study were to examine the trends in incidence rates of subsite-specific colorectal cancer at all stages in a large US population and to explore the impact of age and sex on colorectal cancer incidence. METHODS Data were obtained from the Surveillance, Epidemiology, and End Results (SEER) 9 registries. Colorectal cancer incidence was divided into 3 anatomic subsite groupings: proximal colon, distal colon, and rectum. Incidence rates and relative risk were calculated using the SEER*Stat software provided by the National Cancer Institute. RESULTS From 1976 to 2005, age-adjusted incidence of proximal colon, distal colon, and rectal cancers per 100,000 population have steadily decreased from 22.5, 18.8, and 19.2 to 21.1, 11.7, and 13.6, respectively, contributing to the overall decline in the incidence of colorectal cancer from 60.5 to 46.4. Distal colon cancer had the greatest incidence decline (-37.79%), whereas the most minimal change in the incidence rates occurred for proximal colon cancer (-6.37%) because of increased incidence rates of ascending colon (24.8%) and hepatic flexure (21.3%) over 30 years. The steadily increased proportion of proximal colorectal cancer subsites was observed in both men and women starting at age 50 although women experienced a greater increase than did men. CONCLUSIONS Overall incidence rate of colorectal cancer decreased over the past 3 decades. The percent of ascending colon and hepatic flexure cancers diagnosed at early stages (localized and regional) increased. The finding on sex difference over years suggests that great attention should be paid in the future studies to male and female disparities.

The gold standard for voice restoration after total laryngectomy is tracheoesophageal puncture (TEP). The TEP is a small surgically created fistula in the tracheoeosphageal (TE) wall that may be created at the time of the total laryngectomy (primary TEP) or later after the patient has healed from surgery (secondary TEP). A one-way valved silicone voice prosthesis (VP) is placed into the TEP. The prosthetic valve opens to allow pulmonary air into the vocal tract for vibratory sound production when the tracheostoma is occluded, but remains closed to prevent aspiration of foods/liquids during swallowing.1,2 One of the most difficult complications to manage after TEP is enlargement of the TE fistula that results in aspiration of saliva, liquid, and/or food around the VP into the trachea. Tissue changes associated with radiation, malnourishment, diabetes, smoking, and hypothyroidism may reduce elasticity and integrity of the TEP and have been implicated as potential risk factors for enlarged puncture.3–6 Development of an enlarged TEP has also been associated with acute infection or tumor recurrence.3,7 However, the actual contribution of these potential risk factors is unclear. An enlarged TEP intuitively increases the risk of pneumonia and respiratory complications due to frequent aspiration around the VP. Reduced tissue elasticity also increases the likelihood of spontaneous dislodgement of the VP and consequently the potential for aspiration of the prosthesis. Various treatments, including surgical closure of the TEP, have been proposed to mitigate the ill-effects of an enlarged TEP. Although surgical closure eliminates problems associated with leakage around the prosthesis, closure of the TEP prevents TE voice production, thus negatively impacting quality of life. Because of this, conservative methods, either surgical or nonsurgical, that aim to eliminate leakage around the VP while preserving functional TE voice, either surgical or nonsurgical but excluding complete TEP closure, are of particular interest. Although a variety of conservative treatments have been proposed, there are no clear guidelines for the conservative management of this complication. A better understanding of factors associated with enlarged TEP will lead to more uniform assessment and management of this complication, and may guide preventive efforts. For this purpose, a systematic review was conducted with the following objectives: (1) to estimate the rate of enlarged TEP causing leakage around the VP after total laryngectomy with TEP, (2) to estimate the risk of pneumonia in patients with enlarged TEP, (3) to summarize the effect of potential risk factors for enlarged TEP, and (4) to summarize the type and effectiveness of conservative treatments used to prevent leakage around the prosthesis due to enlarged TEP.

To provide histologic correlation of endoscopic ultrasound (EUS) findings believed to represent chronic pancreatitis (CP).Eighteen postmortem pancreatic specimens in patients dying of all causes were examined in vitro by EUS for features of CP: (1) echogenic foci, (2) hypoechoic foci, (3) echogenic main pancreatic duct (MPD), (4) accentuated lobular pattern, (5) cysts, (6) irregular MPD, (7) dilated MPD, (8) side branch dilation, and (9) calculi. The pancreata were then examined by 2 pathologists (blinded to the EUS/clinical findings) for histopathologic features of CP.Six specimens were autolyzed, and in 1 specimen, MPD could not be seen by EUS. In the other 11 patients, 10 had evidence of CP by EUS (or =3 features) and by histopathologic examination (or =2 features). One patient did not have CP by both EUS and histologic examination.Endoscopic ultrasound accurately detected CP, when compared with histopathologic examination. The presence of 3 or more features of CP correlates with the histologic diagnosis of CP, however, up to 3 features are frequently present in elderly patients dying of all causes. Future studies should address the clinical relevance and the specificity of EUS findings of CP in the older population.

Astronauts live and work in relatively crowded, confined environments on the Space Shuttle and the International Space Station. They experience a unique set of stressors that contribute to a diminishment of many immune responses. This study investigated the ability of the shuttle crew members' monocytes to respond to gram-negative endotoxin that they could encounter during infections. Blood specimens were collected from 20 crew members and 15 control subjects 10 days before launch, 3 to 4 h after landing, and 15 days after landing and from crew members during their annual medical examination at 6 to 12 months after landing. When challenged with gram-negative endotoxin, the crew member's monocytes collected at all three time points produced lower levels of interleukin-6 (IL-6) and IL-1β and higher levels of IL-1ra and IL-8 compared to those of control subjects. Cytokines were assessed by measuring the number of cells positive for intracellular cytokines. These values returned to normal 6 to 12 months after landing, except for IL-1ra, which was still higher (five- to sixfold) than in controls. This phenomenon was accompanied by an increased expression of Toll-like receptor 4 and decreased expression of CD14 on the crew members' monocytes at all time points. There were also increased levels of the lipopolysaccharide binding protein in the plasma of the crew members 3 to 4 h and 15 days after landing. This study shows that spaceflight-associated factors (in-flight and preflight) modulate the response of monocytes to gram-negative endotoxins.

In this article, we report statistical properties of two classes of generalized Gini coefficients (G1 and G2). The theoretical results were assessed via Monte Carlo simulations. Further, we used G1 and G2 on life expectancy to measure health inequalities among the provinces of China and the states of the United States. For China, the results indicated that there was statistically significant health inequality by both G1 and G2. However, for the US, the results showed that there was significant health inequality by G1 but no statistical significance was found in health inequality by G2. Overall, from our study, China has higher health inequality than the United States.

Background Numerous published studies have shown the high diagnostic performance of both EUS and MRCP compared with ERCP for the detection of choledocholithiasis. Design We undertook a systematic review of all published randomized, prospective trials that compared EUS with MRCP with the primary aim being to compare the overall diagnostic accuracy for the detection of choledocholithiasis in patients with suspected biliary disease. Methods A MEDLINE review was performed. We identified 5 randomized, prospective, blinded trials comparing MRCP and EUS for the detection of choledocholithiasis, with subsequent ERCP or intraoperative cholangiography as a criterion standard. The study-specific variables for EUS and MRCP for choledocholithiasis were calculated from the data, and analyses were performed by using aggregated variables (sensitivity, specificity, positive and negative predictive values, and likelihood ratios). Results The pooled data set consisted of 301 patients. The aggregated sensitivities of EUS and MRCP for the detection of choledocholithiasis were 0.93 and 0.85, respectively, whereas their specificities were 0.96 and 0.93, respectively. The aggregated positive predictive values for EUS and MRCP were 0.93 and 0.87, respectively, with the corresponding negative predictive values of 0.96 and 0.92, respectively. Positive likelihood ratios were >10 for both tests, and corresponding negative likelihood ratios approached 0.10 for both tests. No statistically significant differences between EUS and MRCP were found in our analysis. Conclusions EUS and MRCP have high diagnostic performance overall. Our analysis showed no statistically significant difference between the modalities. We recommend taking into consideration other factors, such as resource availability, experience, and cost considerations in deciding between these 2 tests.

EUS training and practice patterns vary widely. The aim of this study was to assess EUS training methods, volumes, and practice patterns, and to obtain subjective assessment of endoscopic competence from endosonographers.A survey was sent to over 1400 U.S. and international gastroenterologists who completed training since 1993. We assessed demographics, whether EUS is performed, how EUS training was obtained, and volume and type of EUS procedures performed in training and at present. Subjective assessment of adequacy of training was also obtained.A total of 157 physicians responded, including 76 EUS performers, of whom 67% completed advanced endoscopy fellowship, 14% were EUS trained during GI fellowship, and 19% learned via other means. EUS performers were subgrouped into those who had and had not completed advanced endoscopy fellowship, and those within and outside of an academic practice. There were significant associations between the number of upper EUS, pancreaticobiliary, and EUS-guided FNAs performed during training (p0.001 for all 3 groups) and completion of advanced endoscopy fellowship. Physicians in academic practice performed more EUS and FNAs per month than physicians in other types of practice (p values0.001 and 0.001, respectively); 93.3% of respondents felt they received adequate instruction in diagnostic EUS, regardless of type of training; 88.9% of EUS performers felt they received adequate instruction in performing FNA.Most EUS performers are in academic practice. Those with advanced training obtained higher training volumes and perform higher volumes of EUS. The majority of respondents felt well trained regardless of training type and the number of procedures performed during training. This is the first analysis to assess these aspects of EUS training and practice.

Comparing correlated lifetimes for a group of individuals to a standard reference population may require variance adjustment of marginal model estimates or the use of conditional random effects models with shared frailty. We present the cumulative relative mortality, the marginal model robust variance estimator and the frailty models in estimating relative mortality for individuals who have correlated lifetimes due to group clustering. The positive stable and gamma frailty distributions are considered in the frailty models. The performances of both marginal and frailty models are compared using simulation. Applying these methods, we show siblings for centenarians had longer life spans than their US cohort reference population.

Summary Selective screening and partner notification are two principal means of preventing and controlling syphilis in the United States, yet few studies have been undertaken to compare and evaluate the cost or effectiveness of detecting syphilis using either strategy. The objective of this paper is to assess from the perspective of a health department the costeffectiveness of selective screening compared with the strategy of partner notification in the detection of early syphilis in Houston, Texas, in 1994 and 1995. The cost-effectiveness analysis was performed using the recurring direct costs associated with detecting syphilis by both strategies. The middle estimates for the total direct costs associated with selective screening and partner notification were $579 101 and $229 529, respectively, for the 1466 and the 567 cases of early syphilis detected. On a cost per case basis, selective screening was more cost-effective than partner notification in the detection of primary, secondary and maternal syphilis cases. However, when consideration was given to prophylactic treatment, partner notification was more cost-effective in the detection of all early stage disease. Our findings suggest that the relative benefit of partner notification over selective screening depends on prophylactic treatment and an increase in worker productivity.

A stochastic model describing the movements, resulting from a smoking cessation program, of a cohort of individuals from the smoking to the non-smoking compartment is proposed. The distribution and first two moments of the number of smokers are derived.

This paper addresses the question of whether sexual activity and partner characteristics differentiate people in different stages of change. Factors expected to distinguish people in different stages of change were partner type, drug use during sex, and HIV status. Three discriminant functions emerged. The loading matrix demonstrates that partner type was the strongest predictor that distinguished people in the precontemplation stage from those in the preparation, action, and maintenance stages (first function) (.962). The loadings on the second discriminant function suggest that when controlling for partner type, HIV status (.935) was the best predictor for distinguishing between the people in the maintenance stage and those in the other stages. The loadings on the third function were not significant. The overall classification results indicate that individuals using crack cocaine and engaging in high risk sexual behaviors can be classified into the stages of change for condom use based on these variables.

This study was conducted to determine whether health education materials were more effective when written at a lower rather than a higher reading level. Women ( n = 252) who visited public health maternity clinics selected either English- or Spanish-language health materials designed to discourage alcohol use, depending on whether the women preferred to read English or Spanish. The materials were written on the third and the 10th-grade reading levels. The women were randomly assigned to receive materials written on one of the two levels. Then participants completed the pre-test, read the health education material and were post-tested immediately. Among English-speaking participants, the material written at the lower reading level was shown to be more effective. Whereas among Spanish-speaking participants, test scores were unchanged after reading either health education material. Overall, we recommend that health care providers design or purchase materials that are easy-to-read and provide face-to-face counseling about abstaining from alcohol. Providers should not rely on written materials to communicate important messages when working with pregnant women.

A patient classification system was developed integrating a patient acuity instrument with a computerized nursing distribution method based on an optimization algorithm. The objective was to minimize the total number of nursing personnel used by optimally assigning the nursing staff to meet the acuity needs of the various clinical units in the hospital. The validity of the model to assign staff was established by a 30-day comparison with the existing manual method of assignment.

There has been little research on the causes of hospitalization when patients are first diagnosed with HIV in the hospital. Reduced access to care could partially explain inpatient diagnosis. We sought to determine if the patients diagnosed as inpatients are hospitalized due to a HIV-related cause versus some other causes, to compare access to care of patients diagnosed with HIV in hospital and outpatient settings, and to determine factors associated with access to care. Participants were newly diagnosed with HIV and recruited between January 2006 and August 2007. The reason for hospitalization was classified as HIV-related, other infectious cause, noninfectious cause, or miscellaneous cause. Access to care was self-reported using a six-item scale and scores were compared with the t test. Multivariate linear regression determined factors associated with improved access to care. Of 185 participants in the study, 78 were diagnosed in hospital and 107 in outpatient settings. Thirty-two percent of participants were female, 90% were racial/ethnic minority, 45% had no high school diploma, and 85% were uninsured. HIV-related conditions accounted for 60% of admissions, followed by non-infectious causes (20%) and other infectious causes (17%). Inpatients did not report less access to care than patients diagnosed while outpatients. Multivariate analysis demonstrated improvement in access to care with better health insurance (p = 0.01) and greater education (p = 0.08). HIV-related preventable conditions account for many hospitalizations when patients are first diagnosed with HIV. While socioeconomic factors are associated with perceived access to care, persons diagnosed in the inpatient setting do not report lower perceived access to care than persons diagnosed as outpatients, suggesting other barriers to earlier diagnosis.

Background The prognosis of esophageal cancer (EC) depends on the depth of tumor invasion and lymph node metastasis. EC limited to the mucosa (T1a) can be treated effectively with minimally invasive endoscopic therapy, whereas submucosal (T1b) EC carries relatively high risk of lymph node metastasis and requires surgical resection. Objective To determine the diagnostic accuracy of EUS in differentiating T1a EC from T1b EC. Design We performed a comprehensive search of MEDLINE, SCOPUS, Cochrane, and CINAHL Plus databases to identify studies in which results of EUS-based staging of EC were compared with the results of histopathology of EMR or surgically resected esophageal lesions. DerSimonian-Laird random-effects model was used to estimate the pooled sensitivity, specificity, and likelihood ratio, and a summary receiver operating characteristic (SROC) curve was created. Setting Meta-analysis of 19 international studies. Patients Total of 1019 patients with superficial EC (SEC). Interventions EUS and EMR or surgical resection of SEC. Main Outcome Measurements Sensitivity and specificity of EUS in accurately staging SEC. Results The pooled sensitivity, specificity, and positive and negative likelihood ratio of EUS for T1a staging were 0.85 (95% CI, 0.82-0.88), 0.87 (95% CI, 0.84-0.90), 6.62 (95% CI, 3.61-12.12), and 0.20 (95% CI, 0.14-0.30), respectively. For T1b staging, these results were 0.86 (95% CI, 0.82-0.89), 0.86 (95% CI, 0.83-0.89), 5.13 (95% CI, 3.36-7.82), and 0.17 (95% CI, 0.09-0.30), respectively. The area under the curve was at least 0.93 for both mucosal and submucosal lesions. Limitations Heterogeneity was present among the studies. Conclusion Overall EUS has good accuracy (area under the curve ≥0.93) in staging SECs. Heterogeneity among the included studies suggests that multiple factors including the location and type of lesion, method and frequency of EUS probe, and the experience of the endosonographer can affect the diagnostic accuracy of EUS.

The authors propose a method to generate information relevant to the decision tree that adds addibonal perspective to the characterization of health quality during survival. Their approach uses survival data to distinguish two attributes of utility. prolongation of life and quality of life (QOL) Health-state transition probabilities correspond to the prolongation of life and are modeled in a discrete-time transient semi-Markov process. Quality-of-life-state transition probabilities are derived from the assumptions of a simple recurrent Markov proc ess They reflect events within the health-state sojourn time that differentiate perceptions of pain and suffering over a short fixed time period. Outcomes for these two dimensions of utility are highly relevant to the assessment of medical technology that might prolong life at the cost of increased pain and suffering, implying a reduced QOL The methods are dem onstrated on a subset of follow-up data from the Beta-Blocker Heart Attack Trial (BHAT). Key words: occupancy statistics, quality of life, transient semi-Markov process, two- dimensional outcome, waiting-time probabilities (Med Decis Making 1992;12:83-92)

Postmarketing research has explored the optimal application schedule of imiquimod 5% cream for treatment of external anogenital warts.We systemically reviewed the published literature on the efficacy and safety of the medication when applied either by a three times per week or once-daily regimen for 16 weeks.MEDLINE (1966 to Feb 10, 2007), Scopus (1996 to Feb 10, 2007), and Cochrane Library (Issue 1, 2007) databases were searched for randomized trials on the medication. Primary efficacy outcome was the proportion of patients completely cleared of warts by end of treatment. Two primary safety outcomes were as follows: (a) proportion of patients who withdrew and (b) proportion of patients who required at least one rest period from treatment because of drug-related adverse events.Six studies were selected for subgroup analysis of circumcised men, uncircumcised men, and women. The once-daily compared to three times per week regimen did not improve treatment efficacy in any of the 3 subgroups (P0.05), but resulted in greater incidence and severity of local skin reactions. There was no difference in medication-related withdrawals between the 2 regimens, although significantly more women and uncircumcised men required at least one rest period with the once-daily than the three times per week treatment schedule (P0.05).The optimal application schedule of imiquimod 5% cream for external anogenital warts is three times per week.

Objective To identify the factors associated with important (≥50%) variation in awareness and practice of evidence-based obstetric interventions in an African setting where we have previously reported poor awareness and use of evidence-based reproductive interventions. Design Cross-sectional analysis of data from our Reproductive Health Interventions Study. Setting North-west province, Cameroon, Africa. Population Health workers including obstetricians, other physicians, midwives, nurses and other staff providing reproductive care. Main outcome measures Prevalence ratios (PR) of uniform awareness and practice of four key evidence-based obstetric interventions from the World Health Organization Reproductive Health Library (WHO RHL): antiretrovirals to prevent mother-to-child transmission of HIV/AIDS, antenatal corticosteroids for prematurity, uterotonics to prevent postpartum haemorrhage and magnesium sulphate for seizure prophylaxis. Methods Comparisons of descriptive covariates, applying logistic regression to estimate independent relationships with awareness and use of evidence-based interventions. Results A total of 15.5% (50/322) of health workers were aware of all the four interventions while only 3.8% (12/312) reported optimal practice. Evidence-based awareness was strongly associated with practice (PR = 15.4; 96% CI: 4.3–55.0). Factors significantly associated with awareness were: attending continuing education, access to the WHO RHL, employment as an obstetrician/gynaecologist and working in autonomous military or National Insurance Fund facilities. Controlling for potential confounding, working as an obstetrician was associated with increased awareness (adjusted prevalence odds ratio [aPOR] = 8.3; 95% CI: 1.3–53.8) as was median work experience of 5–15 years (aPOR = 2.0; 95% CI: 1.0–3.8). Internet access was associated with increased practice (aPOR = 3.4; 95% CI: 1.0–11.8). Other potentially important variations were observed, although they did not attain statistical significance. Conclusions Several factors including obstetric training and continuous education positively influence evidence-based awareness and practice of key obstetric interventions. Confirmation and application of this information may enhance the effectiveness of programmes to improve maternal and perinatal outcomes.

To attempt to confirm a previous report of superior effectiveness of using two thyroid hormones rather than one hormone to treat hypothyroidism.This trial attempted to replicate prior findings, which suggested that substituting 12.5 microg of liothyronine (LT(3)) for 50 microg of levothyroxine (LT(4)) might improve mood, cognition, and physical symptoms in patients with primary hypothyroidism. Additionally, this trial aimed to extend the previous findings to fatigue and to assess for differential effects in subjects with low fatigue and high fatigue at baseline. A randomized, double-blind, two-period, crossover design was used. At an endocrinology and diabetes clinic, 30 adult subjects with primary hypothyroidism stabilized on LT(4) were recruited. Patients randomly assigned to treatment sequence 1 received their standard LT(4) dose in one capsule and placebo in another. Patients assigned to sequence 2 received their usual LT(4) dose minus 50 microg in one capsule and 10 microg of LT(3) in the other. At the end of the first 6 weeks, subjects were crossed over to receive the other treatment. Carryover and treatment effects were assessed by t tests.Of the 30 enrolled study subjects, 27 completed the trial. The mean LT(4) dose was 121 +/- 26 microg/day at baseline. No significant differences in fatigue and symptoms of depression were found between treatments. Measures of working memory were unchanged. During substitution treatment, the free thyroxine index was reduced by 0.7 (P0.001), total serum thyroxine was reduced by 3.0 microg/dL (P0.001), and total serum triiodothyronine was increased by 20.5 ng/dL (P = 0.004).With regard to the outcomes measured, substitution of LT(3) at a 1:5 ratio for a portion of baseline LT(4) yielded no better results than did treatment with the original dose of LT(4) alone.

This study described violent behavior and aggression among youth attending alternative schools, and examined sociodemographic factors associated with such violence. The study involved 494 students attending 10 alternative schools in Houston, Texas. Data were collected between November 2000 and February 2001 by audio-enabled laptop computers equipped with headphones. Students self-reported an average of 11.8 aggressive acts during the week prior to the survey. Students reported a 30-day weapon carrying prevalence of 22.7%; 30-day gun carrying prevalence of 11.1%; 30-day knife or club prevalence of 17.2%; 12-month fighting prevalence of 50.6%; and 12-month prevalence of injuries due to fighting of 6.5%. Association between demographic variables, self-reported aggressive behavior, and other forms of aggression was examined using multivariate logistic regression. Students were divided into four mutually exclusive violence-related categories: no fighting and no weapon (referent), fighting only, carrying weapon only, fighting and weapon carrying. Student aggression was significantly associated with fighting and weapon carrying, with incremental increases at each level (OR 1.1 per unit of increase, 95% CI 1.1-1.2) and in presence of the covariates. Among Houston's alternative school students, the prevalence of violent behavior (weapon carrying, gun carrying, knife or club carrying, fighting, and treatment by a doctor or nurse for injuries) is higher compared to regular high school students. Aggression related strongly to weapon carrying and fighting in the sample. Data indicate alternative school youth urgently need prevention and treatment programs to help them live in safer environments.

In response to growing concern for occupational health and safety in the public hospital system in Costa Rica, a cross-sectional survey of 1,000 hospital-based health care workers was conducted in 1997 to collect baseline data that are being used to develop worker training programs in occupational health in Costa Rica. The objectives of this survey were to: 1) describe the safety climate within the national hospital system, 2) identify factors associated with safety, and 3) evaluate the relationship between safety climate and workplace injuries and safety practices of employees. The safety climate was found to be very poor. The two most significant predictors of safety climate were training and administrative support for safety. Safety climate was a statistically significant predictor of workplace injuries and safety practices, respectively, and there was an underreporting rate of 71% of workplace injuries. These findings underscore the need for improvement of the safety climate in the public hospital system in Costa Rica.

OBJECTIVE— To define the test characteristics of four methods of screening for diabetic retinopathy. RESEARCH DESIGN AND METHODS— Four screening methods (an exam by an ophthalmologist through dilated pupils using direct and indirect ophthalmoscopy, an exam by a physician's assistant through dilated pupils using direct ophthalmoscopy, a single 45° retinal photograph without pharmacological dilation, and a set of three dilated 45° retinal photographs) were compared with a reference standard of stereoscopic 30° retinal photographs of seven standard fields read by a central reading center. Sensitivity, specificity, and positive and negative likelihood ratios were calculated after dichotomizing the retinopathy levels into none and mild nonproliferative versus moderate to severe nonproliferative and proliferative. Two sites were used. All patients with diabetes in a VA hospital outpatient clinic between June 1988 and May 1989 were asked to participate. Patients with diabetes identified from a laboratory list of elevated serum glucose values were recruited from a DOD medical center. RESULTS— The subjects (352) had complete exams excluding the exam by the physician's assistant that was added later. The sensitivities, specificities, and positive and negative likelihood ratios are as follows: ophthalmologist 0.33, 0.99, 72, 0.67; photographs without pharmacological dilation 0.61, 0.85, 4.1, 0.46; dilated photographs 0.81, 0.97, 24, 0.19; and physician's assistant 0.14, 0.99, 12, 0.87. CONCLUSIONS— Fundus photographs taken by the 45° camera through pharmacologically dilated pupils and read by trained readers perform as well as ophthalmologists for detecting diabetic retinopathy. Physician extenders can effectively perform the photography with minimal training but would require more training to perform adequate eye exams. In this older population, many patients did not obtain adequate nonpharmacological dilation for use of the 45° camera.

OBJECTIVE To assess from the perspectives of a government delivery system and patients, the cost-effectiveness of the 45-degrees retinal camera compared to the standard ophthalmologist's exam and an ophthalmic exam by a physician's assistant or nurse practitioner technician, for detecting nonproliferative and proliferative diabetic retinopathy. RESEARCH DESIGN AND METHODS Comparison of 45-degrees fundus photographs with and without pharmacological pupil dilation taken by technicians and interpreted by experts, direct and indirect ophthalmoscopy by ophthalmologists, and direct ophthalmoscopy by technicians with seven-field stereoscopic fundus photography (reference standard). Costs were estimated from market prices and actual resource use. The study included 352 patients attending outpatient diabetes and general-medicine clinics at VA and DOD facilities. RESULTS Medical system costs per true positive were: 45-degrees photos with dilation, $295; 45-degrees photos without dilation, $378; ophthalmologist, $390; and technician, $794. Patient costs per true positive were: 45-degrees photos with dilation, $139; 45-degrees photos without dilation, $171; ophthalmologist, $306; and technician, $1009. Cost-effectiveness is sensitive to program size due to high fixed cost of the camera methods but not to prevalence. Cost-effectiveness of the technician exam is strongly affected by its sensitivity. CONCLUSIONS Primary-care screening with retinal photographs through pharmacologically dilated pupils for diabetic retinopathy is an appropriate and cost-effective alternative to screening by an ophthalmologist in this setting. Ophthalmologists are scarce, primary-care physicians are extremely busy, and large clinics allow fixed equipment costs to be spread across many patients.

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Objectives To determine the overall rate of functional decline and to assess the progression of different signs of Parkinson disease (PD). Patients and Methods Patients with clinically diagnosed PD followed up for at least 3 years were included in this study. Demographic and clinical data (including the Unified Parkinson's Disease Rating Scale [UPDRS]) were analyzed by the multivariate unbalanced repeated-measurements design using the mixed-effects model to study the association between different symptoms and various demographic variables. Regression models helped estimate the rates of progression of the disease in relationship to the various components of the UPDRS. Patients were categorized as having tremor-dominant or postural instability–gait difficulty–dominant PD and the 2 categories were compared for progression of their total UPDRS scores. Design A multivariate mixed-effects model was used to study the relationship between the different symptoms and various demographic variables. Nonparametric statistical tests were used to compare the progression of symptoms in the "on" (good function) state and the "off" (poor function) state groups for 2 age-at-onset categories (≤57 and >57 years). Results Data from 1731 visits on 297 patients (181 men) followed up for an average of 6.36 years (range, 3-17 years) were analyzed. The annual rate of decline in the total UPDRS scores was 1.34 when assessed during the on state and 1.58 when assessed during the off state. Patients with an older age at onset had more rapid progression of PD than those with a younger age at onset. Furthermore, the older-onset group had statistically significantly more progression in mentation, freezing, and parts I (mentation) and II (activities of daily living) UPDRS subscores. Handwriting was the only component of the UPDRS score that did not notably deteriorate during the observation period. Regression analysis of 108 patients whose symptoms were rated during their off state showed a faster rate of cognitive decline as age at onset increased. The slopes (ie, the annual rates of decline) of progression in the UPDRS scores, when adjusted for age at the initial visit, were steeper for the postural instability–gait difficulty–dominant group compared with the tremor-dominant group. Conclusion Based on longitudinal follow-up data, our findings provide evidence for a variable course of progression of the different PD symptoms, thus implying different biochemical or degenerative mechanisms for the various clinical features associated with PD.

In this paper we consider a general illness-death stochastic model in which the transition intensities all vary proportionally to a time function ϕ(t). We extend Chiang's earlier work to include processes which are both reversible and have parameters which are time varying, and obtain survival time distributions and the expectation and variance of survival times.

In this paper we use marginal probabilities to derive expressions for the means, variances and covariances of m-compartment systems. We also present an efficient algorithm for the estimation of the parameters of the system using time series data when measurements are available from k of the m compartments. An application of the analysis and parameter estimation procedure for a model representing the results of a cancer treatment follow-up study is given.

Few studies have examined the long-term effectiveness of behavioral weight control programs. Interpretation of the results from these studies has been limited due to small sample size, use of only one sex, and the number of evaluation parameters. A 2-year follow-up study was designed to assess the effectiveness of a behavioral weight control program on 123 obese male and 386 obese female subjects. Body weights were measured by dietitians at baseline and after an 8-week treatment program. Two-year follow-up weights were selfreported from a mailed questionnaire. The subjects’ mean weight at baseline was 185.6±43.4 Ib (no. = 509). Their mean percent over ideal body weight at baseline was 29.7%. Following an 8-week treatment period, mean weight was 176.4±41.3 Ib (no. = 509), yielding a mean weight loss of 9.2 ±6.4 Ib. Weight change after the 8-week treatment period ranged from a loss of 37 Ib to a gain of 5 lb. The 2-year follow-up study showed that mean weight of the 498 subjects was 179.8 ±42.9 lb, yielding a mean weight loss of 5.8±15.5 Ib. Weight change ranged from a loss of 71 lb to a gain of 47 lb. After 2 years, 325 subjects (65.3%) were still below their baseline weights,182 subjects (36.6% of the entire study group) had maintained or enhanced the weight loss achieved during treatment, and 80 subjects (16.1%) weighed at least 10% less than their baseline weight. The results support the belief that the behavioral weight control program can have an important and lasting impact on the weight status of obese men and women. J Am Diet Assoc 89:1259-1264, 1989.

This paper analyzes the waiting-time distribution of a specific job as it moves through a job-shop with multiple centers and exponential service times. The movement of the job through the shop is governed by a Markovian transition matrix and ends with the job's exit from the shop.

This study analyzed some of the effects of the introduction of cost-sharing on users of the state's health service program. The study population had previously received services at no charge and consisted of people with provider-determined medical need, and included, but was not limited to people in financial need. The study sample was selected from 3 years of program service records (1977-1980). Sampling was random and stratified by key variables. Time-series analysis as well as pre/post-policy comparisons were employed. Analysis of changes in the distributions of service user characteristics and in services provided indicated that use of services was not affected adversely and that lower-income, medically needy people were not deterred from using services following the introduction of cost-sharing. Limitations to the study are reviewed, and implications of using cost-sharing in programs such as Medicaid are considered.

In a discrete-time renewal process we investigate the time of the first occurrence of a time interval of a given length without an event. The generating functions of various distributions of interest are derived as well as the asymptotic behavior of the tail of the distribution of the time of first occurrence.

Blood is a valuable but perishable community resource. Regional blood centers coordinate the blood drawing and inventory policies of the hospital blood banks in a region for more efficient use of the resource. This study used a simulation model to analyze the costs and effects of several different operational policies for a regional blood center. Simulated experiments were carried out in four areas: (1) increasing the amount of blood available, (2) changing the number of delivery vehicles, (3) comparing two types of inventory consignment policies (shipping blood to hospitals with a recall privilege and frequent redistribution of blood amongst regional hospitals) to a direct-sale, no-redistribution policy, and (4) examining the effect of sending fresher blood supplies as inventories to hospitals with lower probabilities of transfusion. The results of the third experiment are presented in detail. It was found that periodic redistribution of the regional inventory yielded lower expiration rates and lower shortage rates. The results of the other three experiments are presented briefly.

Kingman (1962) studied the effect of queue discipline on the mean and variance of the waiting time. He made no assumptions regarding the stochastic nature of the input and the service distributions, except that the input and service processes are independent of each other. When the following two conditions hold: (a) no server sits idle while there are customers waiting to be served; (b) the busy period is finite with probability one (i.e., the queue empties infinitely often with probability one); he has shown that the mean waiting time is independent of the queue discipline and the variance of the waiting time is a minimum when the customers are served in order of their arrival. Conditions (a) and (b) will henceforward be called Kingman conditions and a queueing system satisfying Kingman conditions will be referred to in the text as a Kingman queue.

This paper uses the results from a queueing model to optimize the inventory to be held at the port when exporting a bulk commodity.

This paper presents a computer program for estimating transition probabilities between states in a stochastic model for an illness-death process which incorporates time-dependent covariates. Parameters are estimated by the method of maximum likelihood using the Newton-Raphson iterative procedure. The program provides the standard normal deviate statistics as well as the value of the maximum of the likelihood function which can be used on repeated applications to test hypotheses concerning coefficients associated with covariates. Although this program is demonstrated by using a model with two ‘illness’ states and two ‘death’ states, it is also suitable for analyzing data with models involving fewer states, such as the analysis of survival time with covariates assuming a proportional hazard model.

This paper deals with stochasticm-compartmental systems with continuous time-dependent infusions into all compartments and reversible time-independent flows between any two compartments. A methodology for the first two moments of the distribution of the number of units in the different compartments at any point in time is outlined without resorting to the usual techniques of generating functions and inverse Laplace transforms. A possible application to a systems analysis of the kidney transplant system is discussed.

Hospitals employ disinfection and sterilization techniques to control the transmission of infectious disease agents. In this context, we are not dealing with other important processes relating to the spread of infections, such as food-hand-ling, laundry, etc., but are concentrating on decontamination, washing, rinsing, packaging, and sterilization of hospital surgical and medical treatment supplies that are normally handled by the Central Sterile Supply (CSS).

Ms. MYERS' editorial does not challenge the methods employed in the crippled childrens' cost-sharing study, but, rather, her dissatisfaction with the findings is expressed by stating her own political and philosophic views. Ms. Meyers' feelings about quantification in health services research are discussed in a separate article.' In this commentary we will address only the study, its findings, and its applications. First, Ms. Myers states, "cost-sharing of public funded health services is a complex social policy that can have substantial economic and health status ramifications on program participants." This was the very issue toward which our study was directed. In our first paragraph we outlined the significant lack of agreement and scientific evidence on this issue. Cost-sharing per se has not been shown to have detrimental effects on program participants. In fact, Newhouse's most recent findings make it clear that lower income persons were not affected by cost-sharing in a manner different from higher income persons, especially when the amount of costsharing was based upon income2 (as it was in the program we studied). But even