Progression of asbestosis predicts lung cancer

STUDY OBJECTIVES: To explore whether the progression of asbestosis correlates with the risk of lung cancer among patients with asbestosis. DESIGN: A group of 85 asbestosis patients (78 men and 7 women) were radiographically followed up between 1979 and 1987. Two or three posteroanterior radiographs taken from each patient in 1978 to 1979, 1983 to 1984, and 1986 to 1987 were classified according to the International Labour Office 1980 classification and were used to divide the patients into progressors and nonprogressors. Follow-up for cancer was done automatically through the files of the Finnish Cancer Registry from the time of determination of the progression status to December 31, 1994. Predictors of lung cancer risk were studied with a logistic regression model, and the standardized incidence ratio (SIR) was calculated for lung cancer. RESULTS: Of the 24 male patients with progressive small opacity profusion, 11 (46%) developed lung cancer, as opposed to 5 (9%) of the 54 male patients without progression. The SIR for lung cancer was 37 (95% confidence interval, 18 to 66) for the progressors and 4.3 (1.4 to 9.9) for the nonprogressors. In both groups, all the lung cancer cases occurred among smokers or ex-smokers. None of the seven female patients showed progressive small opacity profusion. One of them developed lung cancer. In the logistic regression model including all 85 asbestosis patients, radiographic progression of small opacity profusion (p=0.0009) and current smoking (0.0021) were significant predictors of lung cancer morbidity. CONCLUSIONS: Asbestosis patients with radiographic progression of small opacity profusion over a few years are at a higher risk of lung cancer than those with a less aggressive course of the disease. The progression of pulmonary fibrosis may be an independent risk factor that, in addition to smoking history and the intensity of asbestos exposure, could be used to estimate lung cancer risk.     

Sunlight exposure and risk of lens opacities in a population-based study: the Salisbury Eye Evaluation project

CONTEXT: Exposure to UV-B radiation in sunlight has been shown to increase the risk of cataract formation in high-risk occupational groups, but risk to the population has not been quantified. OBJECTIVES: To determine the ocular exposure to UV-B radiation in sunlight for a population of older persons and to determine the association between UV-B and lens opacities. DESIGN: The Salisbury Eye Evaluation project, a population-based cohort of older adults. SETTING: Salisbury, Md. PARTICIPANTS: A total of 2520 community-dwelling 65-year-old to 84-year-old adults in Salisbury, Md, from 1993 to 1995, of whom 26.4% were African Americans. MAIN OUTCOME MEASURE: Association of photographically documented cortical opacity 3/16 or greater in at least 1 eye with ocular UV-B exposure, reported in Maryland sun-years of exposure. RESULTS: The odds of cortical opacity increased with increasing ocular exposure to UV-B (odds ratio [OR], 1.10; 95% confidence interval [CI], 1.02-1.20). The relationship was similar for women (OR, 1.14; 95% CI, 1.00-1.30) and for African Americans (OR, 1.18; 95% CI, 1.04-1.33). Analyses of the ocular dose by each age group after the age of 30 years showed no vulnerable age group, suggesting damage is based on cumulative exposure. CONCLUSIONS: Although this population of older Americans has relatively low ocular exposure to UV-B in sunlight, there is still an association between ocular exposure and increasing odds of cortical opacity. Our study found an association among African Americans, which, to our knowledge, has not been reported previously. All sex and racial groups would benefit from simple methods to avoid ocular sun exposure.     

Respiratory health of California rice farmers

Rice farmers are occupationally exposed to agents that may affect respiratory health, including inorganic dusts and smoke from burning of agricultural waste. To assess respiratory health of this occupational group, we conducted a cross-sectional study, including a self-administered health and work questionnaire, spirometry, and chest radiography among 464 male California rice farmers. Mean age +/- SD was 48.3 +/- 15.2 yr; mean duration of rice farming was 25.7 +/- 14.3 yr. Prevalences for respiratory symptoms were: chronic bronchitis (6.3%), physician-diagnosed asthma (7.1%), and persistent wheeze (8.8%). Chronic cough was reported by 7.1% of respondents and was associated with reported hours per year burning rice stubble. Mean FEV1 and FVC were at expected values. FEV1 was inversely associated with years working in rice storage and use of heated rice dryers. Mean FEF25-75 was 93% of expected and was inversely associated with rice storage activities involving unheated rice driers. ILO profusion scores > or = 1/0 for small irregular opacities were seen in 18 (10.1%) of 178 chest radiographs. Study findings suggest increased asthma prevalence among California rice farmers. Radiologic findings consistent with dust or fiber exposure were increased compared with those of the general population, although no associations with specific farming activities were identified.     

Field studies and cost-effectiveness analysis of vaccination with Gavac against the cattle tick Boophilus microplus

This study presents findings from an updated retrospective cohort mortality study of male police officers from January 1, 1950 to December 31, 1990 (n = 2,593; 58,474 person-years; 98% follow-up). Significantly higher than expected mortality rates were found for all cause mortality (Standardized mortality ratio [SMR] = 110; 95% confidence interval [95% CI] = 1.04-1.17), all malignant neoplasms (SMR = 125; 95% CI = 1.10-1.41), cancer of the esophagus (SMR = 213; 95% CI = 1.01-3.91), cancer of the colon (SMR = 187; 95% CI = 1.29-2.59), cancer of the kidney (SMR = 2.08, 95% CI = 100-3.82), Hodgkin's disease (SMR = 313; 95% CI = 1.01-7.29), cirrhosis of the liver (SMR = 150; 95% CI = 1.00-2.16), and suicide (SMR = 153; 95% CI = 1.00-2.24). All accidents were significantly lower (SMR = 53; 95% CI = 0.34-0.79). Mortality by years of police service showed higher than expected rates for (1) all malignant neoplasms in the 1- to 9-years-of-service group; (2) all causes, bladder cancer, leukemia, and arteriosclerotic heart disease in the 10 to 19-year group; and (3) colon cancer and cirrhosis of the liver in the over 30 years of service group. Hypotheses for findings are discussed.     

Variability in the classification of radiographs using the 1980 International Labor Organization Classification for Pneumoconioses

This study describes the extent of agreement in classification of chest radiographs using the International Labor Organization (ILO) classification among six readers from the United States and Canada. A set of 119 radiographs was created and read by three Canadian and three US readers. The two ratings of interest were profusion (scored from 0/- to 3/+) and pleural abnormalities consistent with pneumoconiosis (scored with the ILO system, then collapsed into a yes/no). We used a number of approaches to evaluate interreader agreement on profusion and pleural changes, determining concordance, observed agreement, kappa statistic, and a new measure to approximate sensitivity and specificity. This study found that five of six readers had good fair to good agreement for pleural findings and for profusion as a dichotomous variable (> or = 1/0 vs < or = 0/1) using the kappa statistic, while a sixth reader had poor agreement. We found that concordance, expressed as percent agreement, was higher for normal radiographs than for ones that showed disease, and describe the use of the kappa statistic to control for this finding. This analysis adds to the existing literature with the use of the kappa statistic, and by presenting a new measure for "underreading" and "overreading" tendencies.     

A follow-up program for women with previous gestational diabetes mellitus

OBJECTIVE: To analyse the patterns of attendance in a gestational diabetes mellitus (GDM) follow-up program for detection of impaired glucose tolerance and diabetes mellitus. DESIGN: Retrospective cohort study using computerised data from the GDM follow-up program. PARTICIPANTS AND SETTING: All women with GDM who delivered at the Mercy Hospital for Women in Victoria between 1 January 1981 and 31 December 1995. OUTCOME MEASURES: Enrollment and maintenance in the follow-up program. Predictors of attendance analysed were attendance for the postnatal oral glucose tolerance test (OGTT), severity of GDM, insulin requirement in pregnancy, age at index pregnancy, country of birth, patient booking status and year of index pregnancy. RESULTS: There were 3524 women with GDM delivered during the study period. Attendance for postnatal OGTT was 71% and increased from 43.7% to 69.5% to 84.4% during the three five-year periods of the study (P < 0.00001). Entry into the follow-up program was 58% (1743 of 2986 eligible). A further 538 women (15.3%) were awaiting the postnatal OGTT or first follow-up OGTT. By December 1995, 45% of women who had entered the program had been lost to follow-up. Enrollment in the follow-up program was significantly predicted by insulin requirement in pregnancy (odds ratio [OR], 2.22; 95% confidence interval [95% CI], 1.57-3.13), attendance for postnatal OGTT (OR, 1.94; 95% CI, 1.64-2.29), private patient status (OR, 1.31; 95% CI, 1.12-1.54), severity of GDM (OR, 1.50; 95% CI, 1.24-1.82) and age 30 years or more (OR, 1.37; 95% CI, 1.17-1.60). Maintenance in the follow-up program was significantly associated with attendance for postnatal OGTT (OR, 2.67; 95% CI, 2.19-3.24), insulin requirement in pregnancy (OR, 2.56; 95% CI, 1.87-3.50), age 30 years or more (OR, 1.59; 95% CI, 1.34-1.88) and severity of GDM (OR, 1.55; 95% CI, 1.28-1.89). CONCLUSIONS: There are major difficulties with both recruiting women with GDM into a follow-up program and ensuring their continued attendance. However, a postnatal OGTT and consultation is the most important remediable factor for continuation in a follow-up program. The dedication of the follow-up team administrators rather than the clinical variables of the patients was probably the main determinant of compliance with the follow-up program.     

A case-control study of dietary intake and other lifestyle risk factors for hyperplastic polyps

BACKGROUND & AIMS: Despite the high prevalence of the hyperplastic polyp, little is known about its etiology. The aim of this study was to assess the relationship between diet and other lifestyle factors and the presence of colorectal hyperplastic polyps. METHODS: Information on diet and other known or suspected risk factors for colorectal cancer or adenoma was collected among 81 subjects with hyperplastic polyps and 480 controls. RESULTS: The multivariate-adjusted odds ratio (OR) for hyperplastic polyps for individuals in the upper vs. the lower quartile was 0.30 (95% confidence interval [CI], 0.10-0.88) for dietary fiber, 0.32 (95% CI, 0.11-0.96) for dietary calcium, 0.90 (95% CI, 0.27-2.95) for total fat, and 2.02 (95% CI, 1.05-3.91) for alcohol consumption. Compared with individuals in the lower category, those in the upper category of body mass index had a higher risk for hyperplastic polyps (OR, 4.50; 95% CI, 1.84-10.97). Cigarette smoking was associated with a higher risk (OR, 1.97; 95% CI, 1.02-3.81 for > 20 pack-years vs. never), whereas an inverse association was seen for use of aspirin and other nonsteroidal anti-inflammatory drugs (OR, 0.29; 95% CI, 0.12-0.67 for once per day or more vs. never). CONCLUSIONS: Hyperplastic polyps share common lifestyle risk factors with colorectal adenomas and carcinomas.     

ACE inhibitor use is associated with hospitalization for severe hypoglycemia in patients with diabetes. DARTS/MEMO Collaboration. Diabetes Audit and Research in Tayside, Scotland. Medicines Monitoring Unit

OBJECTIVE: To evaluate the association between the use of ACE inhibitors and hospital admission for severe hypoglycemia and to explore the effects of potential confounding variables on this relationship. RESEARCH DESIGN AND METHODS: The association between the use of ACE inhibitors and the incidence of hypoglycemia is controversial. A recent study reported that 14% of all hospital admissions for hypoglycemia might be attributable to ACE inhibitors. We performed a nested case-control study, using a cohort of 6,649 diabetic patients taking insulin or oral antidiabetic drugs, on the Diabetes Audit and Research in Tayside, Scotland (DARTS) database. From 1 January 1993 to 30 April 1994, we identified 64 patients who had been admitted to Tayside hospitals with hypoglycemia and selected 440 control patients from the same cohort. RESULTS: Hypoglycemia was associated with the use of ACE inhibitors (odds ratio [OR] 3.2, 95% CI 1.2-8.3, P = 0.023), whereas use of beta-blockers and calcium antagonists was not associated with an increased risk of hospitalization for hypoglycemia with ORs of 0.9 (95% CI 0.3-3.3) and 1.7 (95% CI 0.2-2.1), respectively. There were significant differences between case and control patients in type of diabetes treatment, diabetes duration, place of routine diabetes care, and congestive cardiac failure. These differences did not confound the relationship between ACE inhibitors and hypoglycemia (adjusted OR 4.3, 95% CI 1.2-16.0). CONCLUSIONS: The results show that the association between ACE inhibitor therapy and hospital admission for severe hypoglycemia is not explained by these confounding factors. Although ACE inhibitors have distinct advantages over other antihypertensive drugs in diabetes, the risk of hypoglycemia should be considered.     

Bronchopulmonary Kaposi's sarcoma in 106 HIV-1 infected patients

The objectives of this study were to describe the clinical and radiological features at presentation, and the natural history of HIV-related bronchopulmonary Kaposi's sarcoma. A retrospective review of medical records and chest radiographs was performed in 106 HIV-infected homosexual men with bronchopulmonary Kaposi's sarcoma diagnosed at bronchoscopy between September 1988 and November 1994. The majority of patients had evidence of advanced HIV disease at diagnosis (median CD4 cell count was 15 x 10(6)/l, range 0-288), and 93% had had a diagnosis of cutaneous Kaposi's sarcoma for a median duration of 11 months prior to diagnosis of their bronchopulmonary disease. The most frequent symptoms at presentation were cough (92%), dyspnoea (69%), pleuritic pain (20%), haemoptysis (13%) and wheezing (10%). The most common radiological finding in 73% of our series was of poorly defined and confluent opacities, with predominant middle and lower zone involvement. Median survival was 4 months (range 0-37 months) from diagnosis and 9 months (range 1-25) from the onset of symptoms. Treatment with either chemotherapy or radiotherapy was associated with a significantly reduced risk of death (hazards ratio (HR)=0.48, 95% CI=0.26-0.87). Factors associated with a poor survival, after adjustment for treatment effect were older age (HR=1.79, 95% CI=1.22-2.84) for each 10-year increase in age; a history of pleuritic pain (HR=2.97, 95% CI=1.39-6.32); presence of pleural effusion on X-ray (HR=2.01, 95% CI=1.13-3.59) and a prior diagnosis of cutaneous Kaposi's sarcoma (HR=1.8, 95% CI=1.00, 3.24). Bronchopulmonary Kaposi's sarcoma occurs mainly in patients with advanced HIV disease and a prior history of cutaneous disease. Survival is poor, and adverse prognostic factors include older age at diagnosis and the presence of pleural disease.     

Quantification of alterations in structure and function of elastin in the arterial media

The effect of environmental tobacco smoke (ETS) exposure on adults with asthma has not been well characterized. In a prospective cohort study of 451 nonsmoking adults with asthma, we evaluated the impact of ETS exposure on asthma severity, health status, and health care utilization over 18 mo. There were 129 subjects (29%; 95% CI, 25-33%) who reported regular ETS exposure, falling into three categories: exposure at baseline but none at follow-up (n = 43, 10%), no baseline exposure and new exposure at follow-up (n = 56, 12%), and exposure at both baseline and follow-up (n = 30, 7%). In cross-sectional analyses, subjects with baseline ETS exposure had greater severity-of-asthma scores (score difference, 1.7; 95% CI, 0. 2-3.1), worse asthma-specific quality of life scores (score difference, 3.5; 95% CI, 0.03-7.0), and worse scores on the Medical Outcomes Study SF-36 physical component summary (score difference, 3. 0; 95% CI, 0-6.0) than unexposed subjects. They also had greater odds of emergency department visits (odds ratio [OR] = 2.1; 95% CI, 1.2-3.5), urgent physician visits (OR = 1.9; 95% CI, 1.1-3.3), and hospitalizations (OR = 1.9; 95% CI, 1.02-3.6). In longitudinal follow-up, subjects reporting ETS cessation showed improvement in severity-of-asthma scores (score reduction, -3.2; 95% CI, -4.4 to -2. 0) and physical component summary scores (score increase, 5.3; 95% CI, 2.6-8.1). Environmental tobacco smoke cessation decreased the odds of emergency department visits (OR = 0.4; 95% CI, 0.2-0.97) and hospitalizations (OR = 0.2; 95% CI, 0.04-0.97) after adjustment for covariates. Environmental tobacco smoke initiation was associated with greater asthma severity only in subjects with high-level (>= 3 h/wk) exposure (score increase, 1.4; 95% CI, 0.03-2.7). In conclusion, self-reported ETS exposure is associated with greater asthma severity, worse health status, and increased health care utilization in adults with asthma.     

Degradation of weathered oil by mixed marine bacteria and the toxicity of accumulated water-soluble material to two marine crustacea

From 1982 to 1984, the authors conducted a population-based case-control study of lung cancer in men and women nonsmokers in New York State. In-person interviews were completed for 437 lung cancer cases (197 never smokers, 240 former smokers) and 437 matched population controls. Cases and controls were asked to report any history of physician-diagnosed nonmalignant lung disease; cases were more likely than controls to report such a history. Statistically significant associations were found for emphysema (odds ratio (OR) = 1.94, 95% confidence interval (CI) 1.10-3.43), chronic bronchitis (OR = 1.73, 95% CI 1.10-2.72), and the combined endpoint of emphysema, chronic bronchitis, or asthma (OR = 1.82, 95% CI 1.26-2.63). After adjustment for active and passive tobacco smoke exposure, emphysema, chronic bronchitis, and asthma (each condition and the combined endpoint) were significantly associated with lung cancer risk. The risk was more marked for squamous cell carcinomas and for subjects who were diagnosed at older ages, and it remained significant when surrogate interviews were excluded. These results are consistent with the hypothesis that certain prior lung conditions increase the risk of lung cancer in men and women nonsmokers.     

Association between the angiotensin-converting enzyme-insertion/deletion polymorphism and diabetic nephropathy: a methodologic appraisal and systematic review

Recent studies have implicated a variant of the angiotensin-converting enzyme gene (ACE), associated with increased activity of this enzyme, in the development and progression of diabetic nephropathy. This study provides a systematic review of all cross-sectional, case-control, and cohort studies in patients with insulin-dependent (IDDM) or non-insulin-dependent (NIDDM) diabetes mellitus of any race, examining the relationship between the ACE-insertion/deletion polymorphism and nephropathy. Nineteen studies in 21 populations published between 1994 and 1997 presenting data on 5336 patients were reviewed. Two investigators independently assessed the studies on methodologic quality, performance of study, and association between the ACE-insertion/deletion polymorphism and nephropathy. Separate analyses of the relationship between genotype and allele frequencies were performed for patients with IDDM and NIDDM by race, using Peto's odds ratio. In Caucasians with IDDM, pooling was not performed due to heterogeneity of the studies, but among the homogeneous studies, no association was detected. Likewise, no association was observed in Caucasian patients with NIDDM (odds ratio [OR], 1.10; 95% confidence interval [95% CI], 0.83 to 1.45). In Asian patients with NIDDM, the risk of nephropathy was increased in the presence of the DD or ID genotype (OR, 1.88; 95% CI, 1.42 to 2.85). Although this analysis fails to confirm an association between the ACE-insertion/deletion genotype and nephropathy in Caucasians with NIDDM or IDDM, a role for this genetic marker in Asian patients cannot be ruled out. However, due to methodologic limitations of individual studies, no definite conclusions can be drawn from this analysis. Clearly, more rigorous methodology needs to be applied in future studies.     

Crystalline silica and risk of lung cancer in the potteries

OBJECTIVE: To evaluate crystalline silica as a human carcinogen. METHODS: A cohort of 5115 men, born 1916-45 and employed in the pottery, refractory, and sandstone industries of Stoke-on-Trent was identified from occupations subject to health surveillance by the local Silicosis Medical Board (now the Department of Social Security). Detailed occupational and smoking histories, and records of small parenchymal opacities on periodic radiographs were extracted from medical records. An exposure matrix was derived from some 1400 personal or static dust samples and tested against the presence of small parenchymal opacities in a subcohort of 1080 men employed for at least 10 years, who had started working in the industry before 1960. RESULTS: Standardised mortality ratios (SMRs) calculated against mortalities for Stoke-on-Trent, with 95% confidence intervals (95% CIs), were raised for all causes (1.15 (1.05 to 1.26)), lung cancer (1.28 (0.99 to 1.62)) and non-malignant respiratory disease (2.04 (1.55 to 2.65)). Average concentration and duration of exposure to silica were, taken together, significantly related to the presence of small opacities (> or = 1/0). In a nested case-referent analysis of 52 cases of lung cancer and 197 matched referents, conditional logistic regression gave a significantly increased odds ratio (OR) for average silica concentration (micrograms/m3.100), after adjustment for smoking, of 1.66 (1.14 to 2.41) but not for duration of exposure nor, in consequence, for cumulative exposure. CONCLUSION: The association between risk of lung cancer and quantitative estimates of silica exposure supports the SMR analysis and implies that crystalline silica may well be a human carcinogen.     

The relation of cardiovascular disease and its risk factors to the 5-year incidence of age-related maculopathy: the Beaver Dam Eye Study

OBJECTIVE: The purpose of the study is to examine the association between cardiovascular disease and its risk factors and the incidence of age-related maculopathy. PARTICIPANTS: A population of 3583 adults (range, 43-86 years of age at baseline) living in Beaver Dam, Wisconsin, was studied at baseline and 5 years later. METHODS: Standardized protocols for physical examination, blood collection, administration of a questionnaire, and stereoscopic color fundus photography to determine age-related maculopathy were used. Standard univariate and multivariate analyses were performed. MAIN OUTCOME MEASURES: Incidence and progression of age-related maculopathy were measured. RESULTS: After controlling for age and gender, the authors found both higher systolic blood pressure (odds ratio [OR] per 10 mmHg, 1.16; 95% confidence interval [CI] 1.05, 1.27) and uncontrolled treated hypertension (OR 1.98, 95% CI 1.00, 3.94) were related to the incidence of retinal pigment epithelial depigmentation. After controlling for age and gender, the authors found that both blood pressure and uncontrolled treated hypertension were not significantly associated with an increased risk of having exudative macular degeneration develop (for systolic blood pressure, OR 1.18, 95% CI 0.95, 1.45; for uncontrolled treated hypertension, OR 2.10, 95% CI 0.54, 8.11). After controlling for age and gender, the authors found higher pulse pressure was significantly associated with increased incidence of retinal pigment epithelial depigmentation (OR per 10 mmHg 1.27, 95% CI 1.14, 1.42) and exudative macular degeneration (OR per 10 mmHg 1.29, 95% CI 1.02, 1.65). These relations remained significant after controlling for other risk factors in multivariable analyses. CONCLUSIONS: These findings indicate modest relations between higher pulse pressure (a presumed indicator of atherosclerotic vascular disease) and uncontrolled hypertension with increased 5-year incidence of retinal pigment epithelial depigmentation. Overall, however, data from this study show neither consistent nor strong relations between cardiovascular disease and most of its risk factors with the incidence of lesions associated with age-related maculopathy.     

Cellular ingrowth and thickness changes in poly-L-lactide and polyglycolide matrices implanted subcutaneously in the rat

BACKGROUND: The purpose of this study was, to identify predictors of quitting following general practitioners' (GP) anti-smoking counseling. METHODS: We studied determinants (characterized following the Precede framework) of successful quitting (1 year sustained abstinence, biochemically confirmed at 6- and 12-month follow-up) among 861 smokers randomized to the intervention groups based on repeated counseling (RC), RC + spirometric testing, and RC + nicotine gum, in a smoking cessation trial carried out in Turin, Italy. RESULTS: GPs' intervention worked best for male (OR = 2.30; 95% CI, 1.13-4.52) and married (OR = 3.63; 95% CI, 1.37-9.59) smokers, for smokers who had maintained abstinence for at least 1 month in the past (OR = 6.78; 95% CI, 1.56-29.52) or at their first quit attempt (OR = 10.91; 95% CI, 2.37-50.13), and for those who spontaneously reduced their coffee consumption (OR = 3.30; 95% CI, 1.59-6.82); heavy smokers (> = 20 cig/day OR = 0.48; 95% CI, 0.24-0.93) and those living with other smokers (> = 1 smokers in the household: OR = 0.44; 95% CI, 0.22-0.90) were less likely to give up. Previous antismoking advice by the GP represented a strong barrier to success for healthy smokers (OR = 0.19; 95% CI, 0.07-0.52), but not for those reporting symptoms of shortness of breath (OR = 0.63; 95% CI, 0.39-9.20). There were no interactions between predictors and treatment conditions. CONCLUSIONS: Assessment of factors influencing quitting would allow GPs to tailor their message to address existing barriers and to help patients utilize their resources for change.     

Radiographic evidence of silicosis risk in the diatomaceous earth industry

There is limited and conflicting evidence regarding the exposure-response relationship between exposure to crystalline silica and silicosis; the level of risk to current workers remains uncertain. We conducted an epidemiologic investigation of 1,809 workers in the diatomaceous earth industry, where exposures to crystalline silica are primarily to the cristobalite form. On the basis of the median of three independent readings, 81 (4.5%) workers were judged to have opacities on chest radiographs (small opacities, profusion >= 1/0, and/or large opacities). Age-adjusted relative risk of opacities increased significantly with cumulative exposure to crystalline silica. The concentration of respirable crystalline silica to which workers were exposed (highly correlated with period of hire) was an important determinant of risk after accounting for cumulative exposure. For workers with an average exposure to crystalline silica of <= 0.50 mg/m3 (or hired >= 1950), the cumulative risk of opacities for a cumulative exposure to crystalline silica of 2.0 mg/m3-yr was approximately 1.1%; for an average exposure > 0.50 mg/m3 (or hired < 1950), the corresponding cumulative risk was 3.7%. These findings indicate an exposure-response relationship between cumulative exposure to crystalline silica and radiographic opacities; moreover, the relationship was substantially steeper among workers exposed at the highest average concentrations of crystalline silica.     

Correlation of radiologic and pathologic-anatomical findings in dust-induced pneumoconiosis in former coal miners

The ILO classification of small and large opacities is the basis for the compensation of patients with pneumoconiosis. In order to validate the radiological findings, we compared the ILO classification with the gradings of pneumoconiosis in the post mortem investigation (n = 126). An ILO classification of 1/0 used as the threshold value for accepting the diagnosis of a pneumoconiosis was 100% sensitive with a specificity of 2%. With a value of 2/3 the sensitivity decreased to 60% and specificity increased to 74%. The grading of large opacities in the radiograph correlated well with the post mortem findings (rs = 0.71; p < 0.001). For accepting the diagnosis pneumoconiosis from the radiograph alone a threshold value of 1/0 is not specific. The ROC-plot revealed that specificity reached acceptable levels with an ILO classification of at least 2/3.     

Serum carotenoids and tocopherols and incidence of age-related nuclear cataract

BACKGROUND: It is not known whether the protective effects of antioxidants on cataract observed in experimental animals are relevant to age-related opacities in humans. OBJECTIVE: The relations of serum carotenoids and tocopherols to the incidence of age-related nuclear cataract were investigated in a random sample of 400 adults, 50-86 y of age, in the Beaver Dam Eye Study. DESIGN: Nuclear opacity was assessed by using lens photographs taken at baseline (in 1988-1990) and follow-up (in 1993-1995). Nonfasting concentrations of individual carotenoids and alpha- and gamma-tocopherol, were determined from serum obtained at baseline. A total of 252 persons were eligible for incident cataract, of whom 57 developed nuclear cataract in at least one eye. Results were adjusted for age, smoking, serum cholesterol, heavy drinking, adiposity, and, in the tocopherol models, dietary linoleic acid intake. RESULTS: Only serum tocopherol (the sum of alpha- and gamma-tocopherol, in micromol/mmol cholesterol) was associated with cataract. For total serum tocopherol, persons in tertile 3 had a lower risk of cataract than persons in tertile 1 [odds ratio (OR): 0.4; 95% CI: 0.2, 0.9; P = 0.03 for linear trend]. Although serum carotenoids were not significantly associated with nuclear cataract, marginal inverse associations with lutein (OR: 0.3; 95% CI: 0.1, 1.2; P = 0.13 for linear trend) and cryptoxanthin (OR: 0.3; 95% CI: 0.1, 1.3; P = 0.11 for linear trend) were suggested in people < or = 65 y of age. CONCLUSIONS: Findings were compatible with the possibility that nuclear cataract may be linked inversely to vitamin E status, but neither strongly supported nor negated the hypothesized inverse association of nuclear cataract with serum carotenoids.     

Association of secondary and polymicrobial nosocomial bloodstream infections with higher mortality

The objective of this study was to characterize microbiological factors independently associated with higher mortality rates following nosocomial bloodstream infection. All patients admitted to the University of Iowa Hospitals and Clinics between 1 July 1989 and 30 June 1990 who developed a nosocomial bloodstream infection were included. The crude in-house mortality for the 364 patients with nosocomial bloodstream infections was 33%. These deaths accounted for 25% of all in-hospital deaths. Significant risk factors for death from bloodstream infection included diagnoses of cancers and diseases of the cardiovascular and respiratory systems (p < 0.01). Neither previous surgery nor neutropenia was associated with higher mortality rates. Whereas the crude mortality rates associated with gram-negative (33%) and gram-positive (31%) bloodstream infections were similar, that associated with fungemia was higher (54%, p < 0.02). The mortality associated with secondary bloodstream infections (46%) was higher than that associated with primary bloodstream infections (28%, p < 0.001). Furthermore, polymicrobial infections had a worse prognosis than infections from which a single pathogen was isolated (p < 0.05). A multivariate, logistic regression model identified four variables that independently predicted mortality (p = 0.025): age (OR 1.01 per year; CI95 1.00-1.02); cancer (OR 2.35, CI95 1.26-4.37) or diseases of the cardiovascular or respiratory systems (OR 2.20, CI95 1.04-4.67); polymicrobial infection (OR 2.34; CI95 1.21-4.53); and secondary bloodstream infection (OR 2.46; CI95 1.50-4.02). The last variable was the strongest independent predictor. Our study demonstrates the importance of microbiological factors in the outcome of nosocomial bloodstream infections.