Impact of HIV on tuberculosis in Zambia: a cross sectional study.

OBJECTIVE--To examine the contribution of HIV infection to the apparently increasing incidence of tuberculosis in central Africa. DESIGN--Cross sectional study. SETTING--Outpatient clinic in teaching hospital, Lusaka, Zambia. PATIENTS--346 Adult patients with tuberculosis. RESULTS--Overall, 206 patients (60%; 95% confidence interval 54% to 65%) were positive for HIV--in one or both assays used. The peaks for both tuberculosis and HIV infection were among men aged 25-34 years and women aged 14-24 years. Of patients with confirmed pulmonary tuberculosis, 73/149 (49%; 41% to 57%) were positive for HIV; 67/83 (81%; 70% to 89%) patients with pleural disease and 16/19 (84%; 60% to 97%) patients with pericardial disease were positive. HIV positive patients with positive sputum culture were less likely to have had a positive sputum smear, and their chest x ray films less often showed classic upper zone disease or cavitation. Of 72 patients who fulfilled clinical criteria for AIDS, 17 were negative for HIV. CONCLUSIONS--The high prevalence of HIV in patients with tuberculosis suggests that an epidemic of reactivating tuberculosis is arising in those who are infected with HIV. The redirection of public health priorities towards tuberculosis would focus on a major treatable and preventable complication of the AIDS epidemic.     

Epidemiology of hookworm infection in Itagua, Paraguay: a cross sectional study.

A cross-sectional study in Itagua, Paraguay tested 192 people for the presence, intensity and species of hookworm infection. Fifty-nine percent of these individuals were found to be infected. Intensity of infection was determined on 92% of infected individuals by quantitative egg counts. The high intensity hookworm infections, which cause the greatest morbidity, were clustered between the ages of five and 14 years. No differences were seen between genders. The species of hookworm was determined for parasites reared from 72% of infected individuals. Both Necator americanus and Ancylostoma duodenale were identified, although the former species predominated. We conclude that hookworm infection continues to be a public health problem in Paraguay, particularly among children and adolescents who suffer from high intensity infections. A. duodenale continues to persist in the Western Hemisphere and has not been completely displaced by N. americanus.     

Prevalence and patterns of smoking in Delhi: cross sectional study.

OBJECTIVE--To determine the prevalence and predictors of smoking in urban India. DESIGN--Cross sectional. SETTING--Delhi, urban India, 1985-6. SUBJECTS--Random sample of 13,558 men and women aged 25-64 years. MAIN OUTCOME MEASURES--Smoking prevalence; subjects who were currently smoking and who had smoked > or = 100 cigarettes or beedis or chuttas in their lifetime were defined as smokers. RESULTS--45% (95% confidence interval 43.8 to 46.2) of men and 7% (6.4 to 7.6) of women were smokers. Education was the strongest predictor of smoking, and men with no education were 1.8 (1.5 to 2.0) times more likely to be smokers than those with college education, and women with no education were 3.7 (2.9 to 4.8) times more likely. Among smokers, 52.6% of men and 4.9% of women smoked only cigarettes while the others also smoked beedi or chutta. Compared with cigarette smokers, people smoking beedi or chutta were more likely to be older and married; have lower education, manual occupations, incomes, and body mass index; and not drink alcohol or take part in leisure exercise. CONCLUSION--There are two subpopulations of smokers in urban India, and the prevention strategy required for each may be different. The educated, white collar cigarette smoker in India might respond to measures that make non-smoking fashionable, while the less educated, low income people who smoke beedi or chutta may need strategies aimed at socioeconomic improvement.     

Deficient colour vision and interpretation of histopathology slides: cross sectional study.

OBJECTIVE: To determine whether histopathologists with deficient colour vision make more errors in slide interpretation than those with normal colour vision. DESIGN: Examination of projected transparencies of histopathological slides under standardised conditions by subjects whose colour discriminating ability was accurately assessed. SETTING: Departments of histopathology in 45 hospitals in the United Kingdom. SUBJECTS: 270 male histopathologists and medical laboratory scientific officers. MAIN OUTCOME MEASURES: Number of slides correctly identified by subjects whose colour vision was measured on the Ishihara, City University, and Farnsworth-Munsell 100 hue tests. RESULTS: Mean (SD) scores (out of 10) for doctors with colour deficient vision were 9.4 (0.7) v 9.9 (0.4) for controls (P < 0.01) and 7.5 (1.6) v 9.4 (0.7) for scientific officers (P < 0.001). When subjects with colour deficient vision were categorised into severe, moderate, or mild, there was a significant trend towards those with severe deficiency making more mistakes (P < 0.001). CONCLUSIONS: Histopathologists and medical laboratory scientific officers should have their colour vision tested; if they are found to have a severe protan or deutan deficiency, they should be advised to adopt a safe system of working.     

Reliability of distance estimation by doctors and patients: cross sectional study.

OBJECTIVE: To assess the reliability and accuracy of distance estimated by doctors and patients. DESIGN: Comparison between estimated and measured distances of six familiar sites around Guy''s Hospital, London. SUBJECTS: 100 hospital consultants and 100 patients. MAIN OUTCOME MEASURES: Median (range) of estimated distances, and mean (SD) of the difference between estimated and measured distances. RESULTS: Both doctors and patients gave a wide range of estimates of distance. The estimates differed by up to 14.6-fold from the measured distances, and the difference between minimum and maximum estimates was up to 62.5-fold. CONCLUSION: Doctors and patients were inaccurate at estimating distances, which implies that estimates of distances walked are not reliable indicators of a person''s health.     

Screening for diabetes in general practice: cross sectional population study

ObjectiveTo assess the policy proposed by the American Diabetes Association of universal screening in general practice of all patients aged over 45 years for diabetes.Design Cross sectional population study.Setting Local general practice in the United Kingdom.Participants All patients aged over 45 not known to have diabetes.Results Of 2481 patients aged over 45 and not known to have diabetes, 876 attended for screening. There were no significant demographic differences between the screened and unscreened patients. Prevalence of diabetes in patients with age as a sole risk factor was 0.2% (95% confidence interval 0% to 1.4%). Prevalence of diabetes in patients with age and one or more other risk factors (hypertension, obesity, or a family history of diabetes) was 2.8% (1.6% to 4.7%). Four hours a week for a year would be needed to screen all people over 45 in the practice''s population; about half this time would be needed to screen patients with risk factors other than age. More than 80% of patients newly diagnosed as having diabetes had a 10 year risk of coronary heart disease >15%, 73% (45% to 92%) were hypertensive, and 73% (45% to 92%) had a cholesterol concentration >5 mmol/l.Conclusions Screening for diabetes in general practice by measuring fasting blood glucose is feasible but has a very low yield in patients whose sole risk factor for diabetes is age over 45. Screening in a low risk population would best be targeted at patients with multiple risk factors.

What is already known on this topic

Between a third and a half of cases of diabetes are undiagnosed at any one timeNew cases can be identified by screening groups of patients at riskThe American Diabetes Association has proposed the screening of all patients aged over 45 every three years

What this study adds

Screening for diabetes in general practice by measuring fasting blood glucose is feasible but requires much staff timeScreening solely on the basis of age has a very low yield and screening would best be targeted at patients with multiple risk factors for diabetes     

Assessment of methodological quality of primary studies by systematic reviews: results of the metaquality cross sectional study

Objectives To describe how the methodological quality of primary studies is assessed in systematic reviews and whether the quality assessment is taken into account in the interpretation of results.Data sources Cochrane systematic reviews and systematic reviews in paper based journals.Study selection 965 systematic reviews (809 Cochrane reviews and 156 paper based reviews) published between 1995 and 2002.Data synthesis The methodological quality of primary studies was assessed in 854 of the 965 systematic reviews (88.5%). This occurred more often in Cochrane reviews than in paper based reviews (93.9% v 60.3%, P < 0.0001). Overall, only 496 (51.4%) used the quality assessment in the analysis and interpretation of the results or in their discussion, with no significant differences between Cochrane reviews and paper based reviews (52% v 49%, P = 0.58). The tools and methods used for quality assessment varied widely.Conclusions Cochrane reviews fared better than systematic reviews published in paper based journals in terms of assessment of methodological quality of primary studies, although they both largely failed to take it into account in the interpretation of results. Methods for assessment of methodological quality by systematic reviews are still in their infancy and there is substantial room for improvement.     

The validity of general practitioners' self assessment of knowledge: cross sectional study.

OBJECTIVE: To determine whether general practitioners can make accurate self assessments of their knowledge in specific areas. DESIGN: 67 general practitioners completed a self assessment of their level of knowledge over a variety of topics using a nine point semantic differential scale. An objective assessment of their knowledge was then made by administering true-false tests on two of the topics: thyroid disorders and non-insulin dependent diabetes. The study was repeated with another group of 60 general practitioners, using sexually transmitted diseases as the topic. SETTING: General practices in New Zealand. SUBJECTS: Random sample of 67 general practitioners in Auckland. MAIN OUTCOME MEASURE: Test scores for self assessment and for actual knowledge. RESULTS: Correlations between self assessments and test scores were poor for all three topics studied (r = 0.19 for thyroid disorders, 0.21 for non-insulin dependent diabetes, 0.19 for sexually transmitted diseases). CONCLUSIONS: As general practitioners cannot accurately assess their own level of knowledge on a given topic, professional development programmes that rely on the doctors'' self perceptions to assess their needs are likely to be seriously flawed.     

Use of oral corticosteroids in the community and the prevention of secondary osteoporosis: a cross sectional study.

OBJECTIVE--To determine the prevalence of continuous use of oral steroids in the general population, the conditions for which they are prescribed, and the extent to which patients taking oral steroids are taking treatment to prevent osteoporosis. DESIGN--A cross sectional study with a four year retrospective review of drug treatment. SETTING--Eight large general practices in central and southern Nottinghamshire. SUBJECTS--A population of 65,786 patients (52% women) registered with a general practitioner during 1995. RESULTS--303 patients (65% (197) women) aged 12-94 years were currently taking "continuous" (for at least three months) oral corticosteroid treatment. This figure represents 0.5% of the total population and 1.4% (245/17 114) of patients aged 55 years or more (1.7% (166/9601) of women). The usual steroid was prednisolone (97% (294/303)), the mean dose was 8.0 mg/day, and the median duration of oral steroid treatment determined in 149 patients was three years. The most common conditions for which continuous oral steroids were prescribed were rheumatoid arthritis (23% (70)), polymyalgia rheumatica (22% (66)), and asthma or chronic obstructive airways disease (19% (59)). Only 41 (14%) of the 303 patients taking oral steroids had received treatment for the prevention of osteoporosis over the past four years. Although 37 of the 41 patients were women, only 10% (18/181) of the women over 45 years taking continuous oral corticosteroids were currently taking hormone replacement therapy. CONCLUSIONS--If our figures are typical then they suggest that over 250,000 people in the United Kingdom are taking continuous oral steroids and that most of these are taking no prophylaxis against osteoporosis.     

Moderate alcohol consumption is associated with better endothelial function: a cross sectional study

Background

Natural heterologous valved conduits with a diameter greater than 22 mm that can be used for right ventricular outflow tract reconstruction in adults are not commercially available. The purpose of this study was to measure by ultrasonography the maximum diameter of the distended jugular veins of horses and cattle, respectively, to identify a population of animals that would be suitable for post-mortem collection of jugular veins at sizes greater than 22 mm.

Methods

The study population included 60 Warmblood horses, 25 Freiberger horses, 20 Brown Swiss cows, and 20 Holstein cows (including 10 Holstein and 10 Red Holstein). The maximum cross-sectional diameter of the distended jugular veins was measured at a location half-way between the mandibular angle and the thoracic inlet. The thoracic circumference (heart girth length) was used as a surrogate of body size. The jugular vein diameters of the different populations were compared by analysis of variance and the association between heart girth length and jugular vein diameter was determined in each of the four study populations by linear regression analysis.

Results

There was considerable individual variation of jugular vein diameters within each of the four study populations. There was no statistically significant relationship between thoracic circumference and jugular vein diameter in any of the populations. The jugular vein diameters of Brown Swiss cows were significantly larger than those of any of the other populations. Warmblood horses had significantly larger jugular vein diameters compared to Freiberger horses.

Conclusion

The results of this study suggest that the production of bovine or equine xenografts with diameters of greater than 22 mm would be feasible. Differences between species and breeds need to be considered. However, prediction of the jugular vein diameter based on breed and heart girth length in an individual animal is inaccurate.     

The effect of sample handling on cross sectional HIV incidence testing results

Objective(s)

To determine if mishandling prior to testing would make a sample from a chronically infected subject appear recently infected when tested by cross-sectional HIV incidence assays.

Methods

Serum samples from 31 subjects with chronic HIV infection were tested. Samples were subjected to different handling conditions, including incubation at 4°C, 25°C and 37°C, for 1, 3, 7 or 15 days prior to testing. Samples were also subjected to 1,3, 7 and 15 freeze-thaw cycles prior to testing. Samples were tested using the BED capture enzyme immuno assay (BED-CEIA), Vironostika-less sensitive (V-LS), and an avidity assay using the Genetic Systems HIV-1/HIV-2 plus O EIA (avidity assay).

Results

Compared to the sample that was not subjected to any mishandling conditions, for the BED-CEIA, V-LS and avidity assay, there was no significant change in test results for samples incubated at 4°C or 25°C prior to testing. No impact on test results occurred after 15 freeze-thaw cycles. A decrease in assay results was observed when samples were held for 3 days or longer at 37°C prior to testing.

Conclusions

Samples can be subjected up to 15 freeze-thaw cycles without affecting the results the BED-CEIA, Vironostika-LS, or avidity assays. Storing samples at 4°C or 25°C for up to fifteen days prior to testing had no impact on test results. However, storing samples at 37°C for three or more days did affect results obtained with these assays.