Modifiable and non-modifiable risk factors for poor sperm morphology.

STUDY QUESTION: Are common lifestyle factors associated with poor sperm morphology? SUMMARY ANSWER: Common lifestyle choices make little contribution to the risk of poor sperm morphology. WHAT IS KNOWN ALREADY: Although many studies have claimed that men's lifestyle can affect sperm morphology, the evidence is weak with studies often underpowered and poorly controlled. STUDY DESIGN, SIZE, DURATION: Unmatched case-referent study with 318 cases and 1652 referents. Cases had poor sperm morphology (<4% normal forms based on 200 sperm assessed). Exposures included self-reported exposures to alcohol, tobacco, recreational drugs as well as occupational and other factors. PARTICIPANTS/MATERIALS, SETTING, METHODS: Eligible men, aged 18 years or above, were part of a couple who had been attempting conception without success following at least 12 months of unprotected intercourse and also had no knowledge of any semen analysis before being enrolled. They were recruited from 14 fertility clinics across the UK during a 37-month period from 1 January 1999. MAIN RESULTS AND THE ROLE OF CHANCE: Risk factors for poor sperm morphology, after adjustment for centre and other risk factors, included: (i) sample production in summer [odds ratio (OR) = 1.99, 95% confidence interval (CI) 1.43-2.72]; and (ii) use of cannabis in the 3 months prior to sample collection in men aged ≤30 years (OR = 1.94, 95% CI 1.05-3.60). Men who produced a sample after 6 days abstinence were less likely to be a case (OR = 0.64, 95% CI 0.43-0.95). No significant association was found with body mass index, type of underwear, smoking or alcohol consumption or having a history of mumps. This suggests that an individual's lifestyle has very little impact on sperm morphology and that delaying assisted conception to make changes to lifestyle is unlikely to enhance conception. LIMITATIONS, REASONS FOR CAUTION: Data were collected blind to outcome and so exposure information should not have been subject to reporting bias. Less than half the men attending the various clinics met the study eligibility criteria and among those who did, two out of five did not participate. It is not known whether any of those who refused to take part did so because they had a lifestyle which they did not want subjected to investigation. Although the power of the study was sufficient to draw conclusions about common lifestyle choices, this is not the case for exposures that were rare or poorly reported. WIDER IMPLICATIONS OF THE FINDINGS: All participating clinics saw patients at no cost (under the UK National Health Service) and the study population may differ from those in countries without such provision. Even within the UK, low-income couples may choose not to undertake any investigation believing that they would subsequently be unable to afford treatment. Since a computer performed the measurements of sperm morphology, these results may not be comparable with studies where sperm morphology was assessed by other methods. STUDY FUNDING/COMPETING INTERESTS: The study was funded by the UK Health and Safety Executive, the UK Department of Environment, Transport and the Regions, the UK Department of Health (Grant Code DoH 1216760) and the European Chemical Industry Council (grant code EMSG19). No competing interests declared.

Modifiable and non-modifiable risk factors for poor semen quality: a case-referent study.

STUDY QUESTION: Are common lifestyle factors associated with low-motile sperm concentration (MSC)? SUMMARY ANSWER: Common lifestyle choices make little contribution to the risk of low MSC. WHAT IS KNOWN AND WHAT THIS PAPER ADDS: Reviews of male subfertility often highlight how aspects of men's adult lifestyle can significantly increase their risk of subfertility but the strength of supporting evidence is weak. In this study, although low MSC was associated with a history of testicular surgery, being in manual work, not wearing loose underwear and black ethnicity, no relation was found to consumption of alcohol, use of tobacco or recreational drugs or high body mass index (BMI). These results suggest that delaying assisted conception to make changes to lifestyle is unlikely to enhance conception. DESIGN: Unmatched case-referent study with 939 cases and 1310 referents. Cases had a low-MSC relative to the time since last ejaculation (<12 × 10(6) for 3 days of abstinence). Exposures included self-reported exposures to alcohol, tobacco, recreational drugs as well as occupational and other factors. PARTICIPANTS AND SETTING: Eligible men, aged 18 or above, were part of a couple who had been attempting conception without success following at least 12 months of unprotected intercourse and also had no knowledge of any semen analysis. They were recruited from 14 fertility clinics across the UK during a 37-month period from 1 January 1999. MAIN RESULTS AND THE ROLE OF CHANCE: Risk factors for low MSC, after adjustment for centre and confounding factors, included a history of testicular surgery [odds ratio = 2.39, 95% confidence interval (CI): 1.75, 3.28], being in manual work [odds ratio (OR) = 1.28, 95% CI: 1.07, 1.53] or not working (OR = 1.78, 95% CI: 1.22, 2.59) and having black ethnicity (OR = 1.99, 95% CI: 1.10, 3.63). Conversely, men who wore boxer shorts (OR = 0.76, 95% CI: 0.64, 0.92) or who had a previous conception (OR = 0.71, 95% CI: 0.60, 0.85) were less likely to be a case. No significant association was found with smoking and alcohol consumption, the use of recreational drugs, a high BMI or having a history of mumps or fever. BIAS, CONFOUNDING AND OTHER REASONS FOR CAUTION: Data were collected blind to outcome, and exposure information should not have been subject to reporting bias. Among men attending the various clinics less than half met the study eligibility criteria and among those who did, two out of five were not recruited. It is not known whether any of those who refused to take part did so because they had a lifestyle they did not want subjected to investigation. Although the power of the study was sufficient to draw conclusions about common lifestyle choices, it cannot comment on exposures that are perhaps rare and poorly reported: the finding that use of street drugs was unrelated to low MSC cannot be assumed to apply to all such drugs and all patterns of use. The case definition did not consider sperm morphology or sperm DNA integrity. GENERALIZABILITY TO OTHER POPULATIONS: All participating clinics saw patients at no cost (under the UK National Health Service) and the study population may differ from those in countries without such provision. Even within the UK, low-income couples may choose not to undertake any investigation believing that they would subsequently be unable to afford treatment.

Ruminal and total tract phosphorus release from feedstuffs in cattle measured using the mobile nylon bag technique.

Phosphorus (P) excretion in manure is a concern for dairy and beef producers. Excess P released into surface water runoff can lead to eutrophication and algal blooms in streams and lakes. One approach to reducing P excretion is to reduce dietary P. Data regarding P release from feedstuffs is limited and more precise formulations based on specific feed P release in the digestive tract may be one way to lower excreted P. In this experiment, the mobile nylon bag technique was used to determine the disappearance of P in corn silage, alfalfa hay, Coastal bermudagrass hay, and Tifton-85 bermudagrass hay in steers after ruminal (24 h), ruminal + pepsin/HCl (rumen + PHCl), and ruminal + pepsin/HCl + intestinal (rumen + PHCl + I) incubation. Ruminal disappearance of P differed (p < 0.05) between feedstuffs and by site of incubation. Total tract (rumen + PHCl + I) P disappearance for corn silage, alfalfa hay, Coastal bermudagrass hay, and Tifton-85 bermudagrass hay were 90.6%, 93.7%, 83.8% and 84.0% respectively. The range in P release (approximately 7%) indicates that considering P availability when balancing rations could have a measurable impact on subsequent P excretion from ruminants. More data concerning P availability as affected by other feed ingredients or plant species, maturity, and/or quality are needed to more accurately define P release from ruminant feeds.

The virtues of a deliberately mis-specified disease model in demonstrating a gene-environment interaction.

OBJECTIVES: This study seeks to assess the impact of measurement errors in cumulative exposure on estimates of a gene-environment interaction in a nested case-control study in occupational epidemiology. In the approach considered here, exposure intensity is assessed at the group level and the exposure duration individually (both with error). Genetic susceptibility is assumed to be known exactly. Differences in "gene" are assumed to affect disease risk only in exposed subjects. METHODS: Three data analysis strategies were considered: one using a correctly specified disease model (exposure and exposure-gene interaction), and two using mis-specified disease models, one with "gene" as the only risk factor ("gene-only" model) and the other with main effects of both gene and exposure along with their interaction ("full" model). RESULTS: In simulations, estimates of the gene-environment interaction based on the correctly specified disease model were greatly attenuated and power was diminished appreciably even when errors in exposure were modest. Significant associations were detected more frequently in the gene-only model when errors in exposure were large. When the "full" mis-specified model was fitted to the simulated data, it yielded erratic estimates. This is illustrated in an analysis of the interaction of cumulative exposure to organophosphate pesticides and paraoxonase gene on the risk of chronic neuropsychological effects among farmers who dip sheep. CONCLUSION: If "gene" contributes to disease risk only in the presence of exposure, the existence of the gene-environment interaction can be efficiently inferred from a deliberately mis-specified "gene-only" disease model in nested case-control studies.

Chemical form of dietary L-carnitine affects plasma but not tissue carnitine concentrations in male Sprague-Dawley rats.

In Experiment 1, rats (n = 54) were randomly assigned to control or one of the four sources of l-Carnitine supplemented at either 100 or 200 micromol/kg/day and were allowed to acclimate for 14 days. Following a 12-h fast, plasma samples were obtained at 0, 5, 10, 15, 30, 60, 120, 240, 480 and 720 min after l-Carnitine feeding and assayed for free l-Carnitine concentration. Plasma-free l-Carnitine levels were affected by time after treatment intake (p < 0.0001) and l-Carnitine source (p < 0.0001). The time x source interaction was not statistically significant (p = 0.99). In Experiment 2, rats (n = 54) were randomly assigned to control or one of the four sources of l-Carnitine at either 100 or 200 micromol/kg/day and were acclimated as in experiment 1. Rats were sacrificed 120 min after feeding. Samples of liver and skeletal muscle were obtained and assayed for free l-Carnitine concentration. Neither skeletal muscle (p = 0.44) or liver (p = 0.59) tissue concentrations of l-Carnitine were affected by any l-Carnitine source as compared with the control. We conclude that some differences exist in plasma concentrations of free l-Carnitine following ingestion of different chemical forms of l-Carnitine. It is unclear if these differences in the circulating concentration of free l-Carnitine translate into any physiological differences for the animal. In this study, chemical form of l-Carnitine had no effect on skeletal muscle or liver tissue concentrations of l-Carnitine in young male Wistar rats.

Lung cancer and exposure to arsenic in rural Bangladesh.

BACKGROUND: Arsenic is a known carcinogen but the risk of lung cancer from the widespread contamination of drinking water in rural Bangladesh has not been estimated. OBJECTIVES: To determine whether estimated exposure of villagers in Bangladesh to arsenic in drinking water differed between those with lung cancer and those with non-malignant lesions. METHODS: Data were obtained from 7286 subjects who underwent lung biopsy in 2003-2006 at a diagnostic centre taking referrals from throughout Bangladesh. Analysis was limited to 5372 people living in villages for the last 10 years who reported using tube well water. Of these, 3223 with a primary lung tumour were enrolled as cases and 1588 with non-malignant lesions as referents in an unmatched analysis. Arsenic exposure was estimated by average concentrations for each of 64 districts. Logistic regression was used to test the effects of age, arsenic and smoking on risk and to investigate relationship to cell type. RESULTS: Male cases were older than referents and more likely to smoke, to smoke >20 units/day and to smoke bidi-small, hand-rolled cigarettes. Odds ratios for lung cancer increased steadily with mean arsenic concentration, but the confidence interval excluded 1.0 only at concentrations >100 mug/l (OR 1.45, 95% CI 1.16 to 1.80). This trend was seen only in smokers where the increased risk at >100 mug/l was 1.65 (95% CI 1.25 to 2.18). A similar trend was seen in women smokers. Squamous cell lung cancer was more frequent in smokers and, having adjusted for smoking, in districts with arsenic concentrations >100 mug/l. CONCLUSIONS: Among Bangladeshis who smoke, those whose drinking water is contaminated with arsenic at concentrations >100 mug/l are at increased risk of lung cancer. With high levels of exposure misclassification and short latency of exposure, the study cannot estimate or exclude the likely long term risk in non-smokers and at lower arsenic concentrations.

Incidence by occupation and industry of acute work related respiratory diseases in the UK, 1992-2001.

AIMS: To summarise incidence rates and epidemiological characteristics of new cases of work related respiratory disease reported by specialist physicians in thoracic and occupational medicine, with particular reference to occupation, industry, and causal agents for asthma, inhalation accidents, and allergic alveolitis. METHODS: Cases reported 1992-2001 to the SWORD and OPRA national surveillance schemes, in which almost all UK chest and occupational physicians participate, were analysed by age, sex, cause, occupation, and industry, with incidence rates calculated against appropriate denominators. RESULTS: Excluding diseases of long latency, infrequently seen by occupational physicians, the distribution of diagnoses in the two specialties was similar, but with rates generally much higher in occupational than chest physicians. Occupational asthma was responsible for about 25% of cases overall, affecting mainly craft related occupations and machinists, and most often attributed to isocyanates, metals, grains, wood dusts, solders, and welding fume. These same occupations were those at highest risk from inhalation injuries, most frequently caused by irritant gases, vapours, and fume. Among medical technicians and nurses, however, glutaraldehyde and latex were the main causes of occupational asthma. Allergic alveolitis was seldom reported, with almost all cases in agriculture, forestry, and fishing. CONCLUSION: During the 10 year period studied, there were few changes in level of reported incidence, apart from some decline in occupational asthma and inhalation injuries. These results and their implications should be distinguished from much higher estimates of asthma made worse by work derived from population surveys, based on prevalence rather than incidence, and self-reported symptoms rather than diagnoses made by specialist physicians. Even so, the reported incidence of new cases of acute respiratory illness caused by work remains substantial.

Effects of Juniperus species and stage of maturity on nutritional, in vitro digestibility, and plant secondary compound characteristics.

Rising feed costs and recurring feed shortages necessitate the investigation into alternative and underutilized feed resources. Nutritional characteristics of species are either unknown or limited to leaves and ground material from small stems. Therefore, the objective was to quantify nutritional characteristics, 48-h true IVDMD (tIVDMD), microbial gas production, and secondary compound characteristics of entire woody plant material of 4 species-, , , and -at immature and mature stages of growth. Immature plants had greater CP concentrations and lower NDF concentrations ( < 0.001) than mature plants regardless of species. Mature plants also had greater ( < 0.001) concentrations of ADF compared with immature plants with the exception of . In general, immature , , and had greater ( < 0.02) tIVDMD and total 48-h and asymptotic gas production than mature plants. Immature and plants were more digested (tIVDMD; < 0.001) than immature and , but tIVDMD did not differ in mature plant material across species. Condensed tannins (CT) were greater ( < 0.001) in immature and than mature plants; differences in CT concentrations among immature species were also detected ( < 0.04). Volatile oil yields were similar across maturity and species with 1 exception: immature yielded more ( < 0.02) volatile oil than mature material. Volatile oil composition across species varied and contained a range of 65 to 70 terpene compounds. The dominant terpenes across species were generally greater ( < 0.05) in immature vs. mature plant material with the exception of . Labdane acids were negligible in , , and and greater in ( < 0.001). Ground material from mature juniper species, although inferior in nutritional quality compared with immature plants, is comparable to traditional low-quality roughage ingredients. Given that has been successfully fed in lamb feedlot diets, the similarities of , and suggest that all three species have potential to be effective roughage ingredients.

Polymorphisms in the NAD(P)H: quinone oxidoreductase gene and small cell lung cancer risk in a UK population.

NAD(P)H: quinone oxidoreductase (NQO1) protects the cell against cytotoxicity by reducing the concentration of free quinone available for single electron reduction. The NQO1 gene is polymorphic and the variant protein exhibits just 2% of the enzymatic activity of the wildtype protein. In this study, we investigated NQO1 genotype in relation to lung cancer risk in patients attending a Manchester bronchoscopy clinic. The cases were patients with a current, or history of, malignant tumour of the lung, trachea or bronchus. The control group were all other patients attending the clinic who had never been diagnosed with a tumour. DNA extraction from bronchial lavage or blood samples and genotyping was successfully carried out for 82 of the cases and 145 controls. Patients carrying at least one variant allele were found to have almost a 4-fold increased risk of developing small cell lung cancer (adjusted OR=3.80, 95% C.I. 1.19-12.1). No association between NQO1 genotypes and non-small cell lung cancer risk was found. Furthermore, the excess small cell lung cancer risk associated with non-wildtype NQO1 genotypes was only apparent in heavy smokers where there was a >10-fold increased risk (adjusted OR=12.5, 95% C.I. 2.1-75.5). These results suggest that the NQO1 protein may be involved in the detoxification of those carcinogens associated with the development of small cell lung cancer. Individuals with reduced enzyme activity, due to a polymorphism in this gene, may therefore have an increased risk of developing this disease.

Validity of a self-completed questionnaire measuring the physical demands of work.

OBJECTIVES: This study determined the accuracy of workers in quantifying occupational physical demands on a self-administered questionnaire. METHODS: First, a self-administered questionnaire on work postures, manual materials-handling, and repetitive upper-limb movements was validated using direct simultaneous observations for 123 randomly selected employees from 6 occupational settings. Second, weight estimation accuracy was assessed on visual analogue scales for 6 manual materials-handling activities using 20 randomly selected employees from 1 occupational setting. RESULTS: At a dichotomous level (ever-never), the accuracy of most of the self-reported physical demands was good (sensitivity 60-100%; specificity 56-100%). A more-detailed analysis of the dimensions studied (frequency, duration and amplitude) also showed that the accuracy of the self-reported estimates was satisfactory. Full agreement between the estimated and observed frequency was >60% for most of the manual materials-handling activities. In addition the average difference between the estimated and observed duration of the physical demands was found to be small. Finally the average difference between the self-reported and actual weights of various loads was found to be modest. CONCLUSIONS: The self-reported questionnaire used in this study would provide a useful instrument for estimating occupational physical demands and the frequency, duration, and amplitude of these demands in future epidemiologic studies associated with musculoskeletal pain.

Sick building syndrome in a Canadian office complex.

A comprehensive questionnaire survey with limited environmental measurements was undertaken in a large sealed office complex where health complaints had been made by employees since the complex was first occupied. Most respondents suffered from upper respiratory tract irritation, eye and skin irritation, and many less specific complaints. Symptoms started shortly after first employment, were troublesome only at work, and persisted at other work locations within the complex. Employees who worked in cubicles tended to complain more than those who worked in open areas or closed offices; however, evidence of less than optimal ventilation, temperature, and humidity correlated poorly with symptom prevalence. The building was designed and ventilated for open-plan use; later partition into offices and cubicles appeared to aggravate the situation. Although concern about pregnancy outcome was expressed by women who conceived while employed at the complex, rates of spontaneous abortion and fetal defect were close to expectation.

The role of official tax-supported agencies in home care. A personal perspective.

This article examines the role of the tax-supported, official public health agency and compares it with the private, nonprofit agency as both participate in making home health care available.

Effect of supplemental sericea lespedeza leaf meal pellets on gastrointestinal nematode infection in grazing goats.

Feeding sun-dried sericea lespedeza [SL; Lespedeza cuneata (Dum-Cours.) G. Don.] reduces gastrointestinal nematode (GIN) infection in goats fed in confinement, but effects of this forage when fed as a supplement to goats on pasture are unclear. A study was completed in which supplemental feeds (75 and 95% SL leaf meal pellets and a commercial pellet, all fed at 0.91 kg/head/day) were offered to thirty growing male Spanish goats (9 months old, 20.6 ± 2.8 kg, 10/treatment) grazing perennial warm-season grass pastures in Fort Valley, GA, from September to November, 2010. Fecal and blood samples were taken from individual animals weekly to determine fecal egg count (FEC) and packed cell volume (PCV), respectively, and animal weights were recorded at the start and end of the trial. After 11 weeks grazing, animals were slaughtered for recovery, counting, and speciation of adult GIN from the abomasum and small intestines. There was no difference in FEC between goats fed the 75 and 95% SL leaf meal pellets, but both groups had lower (P<0.05) FEC than the goats fed the commercial pellets from days 35 to 77. The PCV values were not affected by the dietary treatments. Animal gain per day averaged 102.0, 77.2, and 53.3g for goats fed 95% SL, commercial, and 75% SL pellets, respectively (P<0.05). The 95% SL leaf meal pellet goats had 93.0 and 47.3% fewer (P<0.05) total (male+female) adult Haemonchus contortus and Teladorsagia circumcincta, respectively, than control animals, while only male H. contortus were lower (47.6%; P<0.05) in 75% SL-fed goats compared with commercial pellet-fed animals. Feeding supplemental SL leaf meal pellets improved animal performance (95% SL pellets) and reduced worm burdens (75 and 95% SL pellets) in young grazing goats and is a useful tool for natural GIN control in small ruminants.

GST CYP and PON1 polymorphisms in farmers attributing ill health to organophosphate-containing sheep dip.

Previously we reported that in sheep dippers exposed to organophosphates the frequency of paraoxonase (PON1) polymorphisms differed between those with or without self-reported ill health. We have now examined whether polymorphisms in other genes involved in xenobiotic metabolism alter disease risk in this population. There were elevated but non-significant risks associated with the CYP2D6 WT genotype (odds ratio (OR) 1.47, 95% CI 0.83-2.60), or a GSTP1*B or *C allele (OR 1.37, 95% CI 0.88-2.01) or being GSTM1*2/GSTT1*2 homozygous (OR 1.61, 95% CI 0.74-3.48). Similar results were generally obtained after the exclusion of subjects to obtain a more homogenous case-referent population: for double null GSTM1 and GSTT1 homozygotes the OR was 2.06 (95% CI 0.85-2.04). In those also likely to have been exposed to diazinon, risks associated with a GSTP1*B or *C allele (OR 1.82, 95% CI 0.92-3.63) or a GSTM1*2/GSTT1*2 homozygous (OR 2.60, 95% CI 0.72-10.42) were elevated but not to a significant extent. Risk associated with PON1 genotype and phenotype varied with CYP2D6 and GSTP1 genotype but not consistently with a priori hypotheses. Further work is necessary to delineate more clearly pathways of organophosphate activation and non-PON1 pathways of detoxification and to confirm whether CYP and GST polymorphisms alter disease risk in populations exposed to organophosphates.

Paraoxonase polymorphisms and self-reported chronic ill-health in farmers dipping sheep.

BACKGROUND: Serum paraoxonase (PON1) provides protection against organophosphate induced toxicity. Recently we reported that the frequency of paraoxonase polymorphisms in sheep dippers with self-reported chronic ill-health differed from that in dippers with a similar dipping history but no ill-health. As these analyses may have included subjects with conditions unrelated to organophosphate exposure, the aim of this study was to examine whether the risk associated with PON1 polymorphisms varied using a more homogenous case and referent population. METHODS: Each subject completed a detailed symptom questionnaire and their general practitioner was asked whether there was any history of neurological disease that could be confused with the effects of organophosphate poisoning. Subjects were then excluded both on clinical grounds and where identified as atypical on discriminant analysis. RESULTS: Risk associated with the PON1 192 and 55 genotypes altered little with these changes in the population. CONCLUSIONS: These findings are consistent with the hypothesis that organophosphates contribute to the self-reported ill-health of sheep dippers.

The incidence of work-related disease reported by occupational physicians, 1996-2001.

In the course of six calendar years, 1996-2001, 5491 new cases of work-related disease were reported by a 1-in-12 random sample of occupational physicians throughout the UK. This represented an estimated total of almost 66 000, or 11 000 cases per annum. These cases have now been analysed by sex, occupation (nine categories) and industry (eight categories), and annual average incidence rates calculated in five main disease groups against a similarly classified denominator of 3.2 million employees served by the same physicians. The overall average annual estimated rate (342 per million) was eight times higher than that reported by clinical specialists, calculated in a similar manner against the entire employed population of the UK (28 million), but 17 times higher for musculoskeletal disease. For men employed in mines and quarries, and both men and women in metallic and automotive manufacture, rates for most types of disease were very high. Occupations with the highest rates were craftsmen and female associate professionals. In all these occupational and industrial groups with high rates, musculoskeletal complaints were the main cause, and skin, respiratory or stress diseases were next in importance. In each type of disease, there was a wide range in incidence rates, suggesting important differences in risk by occupation or industry.

Prognosis and work absence due to occupational contact dermatitis.

The consequences of a diagnosis of occupational contact dermatitis (OCD) were investigated using cases available from the voluntary surveillance scheme, EPIDERM. Cases of OCD reported from November 1994 to September 1995 were identified and sampled to give at least 100 cases of allergic, irritant and mixed OCD reported by consultant dermatologists (344 cases) and occupational physicians (377 cases). A questionnaire was sent to the reporting physician to elicit further information. 512 completed questionnaires were returned, of which 510 were eligible for analysis. Among cases reported by dermatologists (n = 286) and occupational physicians (n = 224), 7% (6.3%) had been unemployed and 16.8% (20.1%) had taken sick leave. 3 factors independently predicted time off work in a logistic regression analysis: age OR = 1.25 (95% CI, 1.05-1.49), allergic dermatitis OR = 1.77 (95% CI, 1.13-2.79) and medicolegal assessment OR = 4.42 (95% CI, 2.20-8.89). Overall, 15.7% did not improve clinically between the first and last visit. Those who did not improve had been exposed to the agent for longer (mean 7.6 years) than those who did (5.3 years) (p = 0.09). In patients

A study of lung function and chest radiographs in men exposed to zirconium compounds.

Men working with zirconium compounds at one site in the North of England have been monitored since 1975 to evaluate effects on the lung of exposure (mainly < 10 mg/m3) over many years. Chest radiographs (in 1975, 1978, and 1982) and lung function measurements (from 1975-1988) were carried out on all men (178) known to have worked with the compounds and an estimate of cumulative exposure was computed from job title and likely exposures in each era. No evidence was found that zirconium exposure resulted in abnormal chest radiographs or impaired pulmonary function.

Organic brain damage and occupational solvent exposure.

Three hundred and nine men with organic dementia, cerebral atrophy, or psycho-organic syndrome admitted for five nights or more to one of 18 Quebec hospitals were individually matched with patients admitted (1) with some other psychiatric diagnosis and (2) to a general hospital. Lifetime occupational histories were obtained by telephone. Occupational exposure to solvents was assessed blind to type of case by (1) individual ratings and (2) a job exposure matrix; men who worked in moderate or high solvent concentrations for at least 10 years were considered exposed. With the psychiatric referent series, an odds ratio of 1.4 (90% CI 1.0-2.0) was calculated by individual exposure ratings and 1.4 (90% CI 0.9-2.2) by job matrix. Increased risk was mainly in those with organic dementia or cerebral atrophy and an alcohol related diagnosis. The same pattern of risk was found against the general hospital referents. Adjustment for possible confounders did not alter the risk estimates appreciably. Also, lifetime job histories, compared in selected case-referent pairs, gave similar evidence of increased risk (odds ratio 2.3; 90% CI 1.0-5.5). It is concluded that the combined effect of occupational solvent exposure and alcohol intake is probably an important cause of organic brain damage.