Evaluation of the accuracy of aorta scan BVI 9600 in screening for abdominal aortic aneurysm.

OBJECTIVES: Despite a decreasing incidence of abdominal aortic aneurysm (AAA), the cost-effectiveness of AAA ultrasound screening can be improved by reducing the screening costs and increasing the uptake rates. The BVI 9600 (BVI) is a promising tool for this purpose as it is inexpensive and can detect AAA without a trained operator. This study aims to investigate whether the BVI can be used to detect AAA for the purpose of a low-cost outreach screening approach. METHODS: A total of 142 subjects had their abdominal aortae measured by five sonographers using the BVI and a conventional ultrasound machine. The examination included four anterior-posterior measurements at four equally spaced scanning locations from the xiphisternum to the umbilicus. The measurements produced by each machine were compared using Bland-Altman plots, followed by an analysis of the AAA detection performance. RESULTS: The BVI measured the aortic diameter to within 0.88-1.56 cm of the true diameter, exceeding the 0.5 cm "clinically acceptable difference" (CAD). Its accuracy was poorer when measuring the aneurysmal aortae (mean difference -0.56 cm, variability 1.72 cm) than normal aortae (mean difference 0.02 cm, variability 0.76 cm). Nine out of 52 aneurysms were not detected due to undersizing measurement and non-visualization of the aortae. CONCLUSIONS: At present, the BVI is not sufficiently accurate to detect AAA for screening purposes. A number of technical features require improvement.

Obesity and impaired venous function.

OBJECTIVES: The clinical severity of venous disease is often worse in obese patients. The objectives of this study were to compare lower limb venous physiology assessed by air plethysmography in a large group of obese and normal-weight patients; to consider the effect of posture on these measures and on foot vein pressure in a smaller cohort. METHODS: Venous function was assessed using air plethysmography and duplex scanning in 934 consecutive patients presenting for assessment of venous disease. These were grouped into obese or non-obese categories. A smaller group of twenty patients with a range of body weights were randomly selected from a database of patients with varicose veins. Foot vein pressures and femoral vein diameter were measured standing, sitting, lying and ambulating. RESULTS: Venous disease was more clinically severe in the obese limbs (CEAP C5&6 non-obese group 20.5%, obese group 35.4%, p<0.001 chi(2)). Venous reflux was worse in the obese but measures of muscle pump function were better. Residual volumes and fractions were better in the obese (mean residual volume, non-obese 60 SD 36, obese 50 SD 42, p<0.001 t test). In the smaller study group weight correlated with the diameter of the superficial femoral vein (r=0.50), ambulatory venous pressure (r=0.45), venous filling index (r=0.49) and the ejection volume (r=0.38, p<0.05). The foot venous pressure was significantly greater in the obese in all positions. CONCLUSION: The CEAP clinical stage of venous disease is more advanced in obese patients than non-obese patients with comparable anatomical patterns of venous incompetence. This may be the result of raised intra-abdominal pressure reported in previous studies, leading to greater reflux, increased vein diameter and venous pressures.

Incidence of deep vein thrombosis after varicose vein surgery.

BACKGROUND: Varicose vein surgery is generally considered to have little risk of postoperative deep vein thrombosis (DVT). This prospective study examined the incidence of DVT in patients undergoing varicose vein surgery. METHODS: Lower leg veins were assessed before operation by duplex ultrasonography in 377 patients, and reassessed 2-4 weeks after surgery, and again at 6 and 12 months. Patients were instructed to contact a physician if symptoms consistent with DVT occurred before the scheduled follow-up appointment. Preoperative prophylaxis (a single dose of subcutaneous heparin) was left to the discretion of the vascular surgeon. RESULTS: DVT was detected in 20 (5.3 per cent) of the 377 patients. Of these, only eight were symptomatic and no patient developed symptoms consistent with pulmonary embolus. Eighteen of the 20 DVTs were confined to the calf veins. Subcutaneous heparin did not alter the outcome. No propagation of thrombus was observed and half of the DVTs had resolved without deep venous reflux at 1 year. CONCLUSION: The incidence of DVT following varicose vein surgery was higher than previously thought, but these DVTs had minimal short- or long-term clinical significance.

Non-saphenofemoral venous reflux in the groin in patients with varicose veins.

OBJECTIVES: To investigate the incidence, clinical significance, anatomical variation and physiology of non-saphenofemoral venous reflux (non-SF reflux) in the groin. DESIGN: Prospective study. MATERIALS: A total of 1072 vascular diagnostic workups in 680 patients with possible venous diseases to the legs were included. METHODS: Duplex scanning and air plethysmography. RESULTS: A total of 1022 legs had venous diseases. Of these, 101 (9.9%) had non-SF reflux in the groin. Such reflux occurred in recurrent varicose veins (RVV) in 16.3%, in primary varicose veins (PVV) in 6.1% and in deep venous thrombosis (DVT) in 8.0%. Two patterns of reflux were distinguished: epigastric reflux from lower abdominal wall veins (71 legs) and pudendal reflux from perineal and/or gluteal veins (30 legs). Pudendal reflux was almost exclusive to women and did not occur with DVT. If there was only non-SF reflux at the groin the venous filling indices (VFI) were close to normal (1.7+/-1.0 ml/s for RVV, 1.9+/-1.2 for PVV, 1.7+/-1.0 for DVT) and no active ulcers were observed. However, if non-SF reflux was associated with saphenofemoral or other reflux the VFIs (3.3+/-2.3 ml/s for RVV, 3.8+/-1.5 ml/s for PVV) were abnormal (p <0.05) and ulcers occurred in 11/32. CONCLUSION: Non-SF reflux in the groin is common. Such reflux may be missed at initial surgery and lead to recurrence of varicose veins. However, the venous physiological disturbance of such reflux is mild and it is not associated with ulcers unless combined with reflux at other sites in the leg.

Cancer in the mothers and siblings of testicular cancer patients.

Some families seem to have an increased risk of several different cancers and a reduced risk of others. Either genetic predisposition or a shared environment may explain this familial clustering, and the type of cause can affect how family members should be advised. We used data from a case-control study to examine the risk of cancer in the mother, sisters and brothers of men with testicular cancer. Our results show a significant relative risk (RR=1.7; 95% confidence interval (CI): 1.05-2.6) of cancer for sisters of testicular cancer patients in comparison with the sisters of controls. When data were combined for brothers and sisters, the RR for all cancers was 1.53 (CI: 1.1-2.3). Despite the limitations of our data, there is evidence for cancer clustering in the families of testicular cancer patients. Unfortunately, the evidence is consistent with either a genetic or environmental etiology.

Is occupation a risk factor for thyroid cancer? Canadian Cancer Registries Epidemiology Research Group.

A Canadian case-control study explored the etiology of thyroid cancer, including occupational exposure. Analysis of job history from 1272 thyroid cancer patients and 2666 controls revealed statistically significant risks among the following occupations: Wood Processing, Pulp and Papermaking (odds ratio [OR] = 2.54, 95% confidence interval [CI] = 1.11-5.83); Sales and Service (OR = 1.26, 95% CI = 1.05-1.52); and Clerical (OR = 0.81, 95% CI = 0.67-0.97). ORs were adjusted for age, sex, province, cigarette smoking, education, self-reported exposure to radiation at work, and duration of employment. Exposure to ionizing radiation or electromagnetic fields at work (inferred from job histories) did not affect risk, nor did socioeconomic status, measured by education, income, or occupational prestige. Possible explanations for the results and further investigations are discussed.

Venous physiology in the different patterns of recurrent varicose veins and the relationship to clinical severity.

Venous function measured by air-plethysmography (APG) was compared to anatomical patterns of reflux assessed by duplex scanning and associated clinical features in 253 limbs with recurrent varicose veins following previous superficial venous surgery. The results showed that a previous history of deep venous thrombosis, previous procedure with preservation of the long saphenous vein, and a history of healed ulcer or current ulcer were each associated with worse venous function. Patterns of reflux which included multiple sites of reflux and presence of deep incompetence were also associated with worse venous function. Where there was reflux in the groin, limbs with a wide recurrent saphenofemoral junction presented the worst venous filling time and venous filling index, whereas those with reflux unrelated to the common femoral vein had nearly normal venous physiology and occurred almost exclusively in females. The other patterns of recurrence in the groin were physiologically indistinguishable from each other. In conclusion, certain patterns of reflux, clinical and operative features are associated with worse venous physiology in limbs with recurrent varicose veins. These features of recurrence with more severe physiological disturbance may necessitate a higher priority for surgical intervention.

Archie Cochrane and his legacy. An internal challenge to physicians' autonomy?

Archibald L. (Archie) Cochrane was born in 1909 into a wealthy Scottish family, from which he inherited the advantage of a private income and the disadvantage of porphyria. Though a brilliant student, his medical training was interrupted by a lengthy psychoanalysis in Europe, and by service in a field ambulance unit in the Spanish Civil War. Eventually Cochrane qualified in medicine in 1938 and joined the R.A.M.C. in 1939. He was taken prisoner in Crete in 1941 and served the rest of the war as medical officer in various POW camps. Cochrane's post-war career with the Medical Research Council as a field epidemiologist in South Wales earned him the respect and admiration of a generation of British epidemiologists. However, Cochrane's international reputation is not based on his achievements as an epidemiologist, but on his 1971 monograph "Effectiveness and Efficiency. Random Reflections on Health Services," a biting scientific critique of medical practice. Cochrane died in 1988, but his name lives on in the Cochrane Collaboration, a network of researchers devoted to clinical trials, and the torch which he lit had been carried forward by the groups promoting evidence-based medicine. Some have looked askance at these developments, regarding them as a threat to the autonomy of physicians.

A simple method for estimating incidence from prevalence.

A two-state deterministic model is used to estimate the incidence of an irreversible disease from prevalence and mortality data. The method is simpler than those described previously. Diabetes and dementia are used as examples.

Marital status, dementia and institutional residence among elderly Canadians: the Canadian Study of Health and Aging.

The association between marital status and mortality is well known; marital status has also been related to morbidity. In this paper, we examine the importance of marital status in relation to the presence or absence of dementia and to institutional residence, using data from the Canadian Study of Health and Aging. Three groups are compared: married, single and previously married. We show that the age-standardized prevalence of dementia and the proportions of elderly Canadians living in institutions with and without dementia are highest among single people and are also high for those who were previously married. These associations hold true for both women and men, but the relation between marital status and institutionalization is much stronger for men. Possible explanations and implications for the future care of the elderly are discussed.

Sunlight exposure, hat use, and squamous cell skin cancer on the head and neck.

BACKGROUND: Sunlight is the environmental exposure most often associated with squamous cell cancer (SCC) of the skin. It can be difficult to quantify the sunlight exposure of the skin because of the different types of clothing that may be worn. The problem is simplified for studies of SCC on the skin of the head and neck, where a hat is the only type of clothing that needs to be considered. OBJECTIVE: The purpose of the study was to determine the risk for SCC of sunlight exposure on the skin of the head and neck, and the protective effect, if any, associated with wearing a hat. METHODS: A case-control study of squamous cell carcinoma of the skin was conducted amongst men in the province of Alberta, Canada. Analysis was restricted to only those cases where cancer occurred on the head or neck, and their age and sex matched controls. RESULTS: Ethnicity, non-sunexposed skin colour, and hair colour each significantly affected the SCC risk. An increased SCC risk was also associated with greater cumulative sunlight exposure and with sunburns experienced during the ages 5 to 15 years. The risk associated with sunlight exposure was significantly elevated in men who reported that they had always or usually worn a hat. CONCLUSION: As observed in previous studies, SCC on the skin of the head and neck is associated with host pigmentation, sunburns occurring in childhood, and sunlight exposure during adulthood. The risk observed for wearing a hat may be due to bias or confounding; however, hats remain an unproven means of protection against SCC on the skin of the head and neck.

Preterm birth: associations with genital and possibly oral microflora.

Opportunistic pathogenic microbes are indigenous to the female lower genital tract and etiologic in many types of pelvic infections and, apparently, a portion of preterm birth (PTB) cases. Bacterial vaginosis (BV) is a clinical syndrome based on an altered genital microflora in which Gardnerella vaginalis; anaerobic species primarily among Prevotella, Porphyromonas, Bacteroides, Peptostreptococcus, and Mobiluncus; Mycoplasma hominis; and Ureaplasma urealyticum become predominant in vaginal secretions. This BV complex of microbes, compared to a normal vaginal microflora dominated by facultative lactobacilli, is associated with significantly increased risks for preterm labor, preterm premature rupture of membranes, PTB, and other perinatal infectious complications. Pathogenetic mechanisms include an ascending route of infection and/or inflammatory process due to microbial products and maternal and/or fetal response(s) with production of prostaglandins and cytokines. In the presence of periodontal disease, oral opportunistic pathogens and/or their inflammatory products also may have a role in prematurity via a hematogenous route. Fusobacterium nucleatum, a common oral species, is the most frequently isolated species from amniotic fluid cultures among women with preterm labor and intact membranes. Also, the species and subspecies of fusobacteria identified from amniotic fluid most closely match those reported from healthy and diseased subgingival sites, namely F. nucleatum subspecies vincentii and F. nucleatum subspecies nucleatum, compared to strains identified from the lower genital tract. Although these fusobacteria also could be acquired through cunnilingus from a partner, new data associating maternal periodontal disease with preterm low birth weight taken with the isolation of F. nucleatum, Capnocytophaga, and other oral species from amniotic fluid support further study of a possible additional route, oral-hematogenous, to PTB.

Childhood asthma.

OBJECTIVES: This article describes trends in the prevalence of asthma among children aged 0 to 14 from 1978/79 to 1994/95, and in hospital separations for asthma from 1974/75 to 1994/95. It also examines factors associated with childhood asthma. DATA SOURCES: Information on asthma among children aged 0 to 11 is from the 1994/95 National Longitudinal Survey of Children and Youth (NLSCY), and among children aged 12 to 14, from the 1994/95 National Population Health Survey (NPHS). Hospital separation data are from the Hospital Morbidity File. Mortality data are from the Canadian Vital Statistics Data Base. ANALYTICAL TECHNIQUES: Prevalence estimates of asthma were calculated based on a sample of 22,831 children aged 0 to 11 from the NLSCY and 637 children aged 12 to 14 from the NPHS. Logistic regression was used to estimate the odds of asthma among children aged 0 to 11 by selected characteristics. MAIN RESULTS: The prevalence of childhood asthma and hospital separations rates for asthma have increased sharply. A history of bronchitis and allergies, parental asthma, and residence in the Atlantic provinces and Quebec are associated with higher rates of asthma in children.

Incidence and mortality of neuroblastoma in Canada compared with other childhood cancers.

The incidence and mortality of neuroblastoma was reviewed in the general context of childhood cancer in Canada for the periods 1982-86 and 1987-91. This was done to complement the preliminary work of the Quebec Neuroblastoma Screening Project that is studying the impact of screening North American infants for the preclinical detection of neuroblastoma on population-based mortality. Annual age-standardized incidence rates for all childhood cancer in Canada appear to have declined slightly (nonsignificantly) from 155.1 to 150.8 per million, between 1982-86 and 1987-91; the rates for neuroblastoma were stable between the two five-year periods (11.8 per million in 1982-86 and 11.4 per million in 1987-91). With respect to mortality, the age-standardized rates for childhood cancer in Canada have shown a declining trend between the first and second halves of the decade, from 43.4 to 34.7 per million, while the rates for neuroblastoma have not changed (4.4 and 4.2 per million). The age-specific distributions of incident cancers indicate that neuroblastoma accounts for the greatest proportion of all cancers in children less than one year of age. Similarly, neuroblastoma is the leading cause of cancer deaths in children aged one to four years. Theoretically, infants less than one year of age could benefit most from effective preventive interventions, treatment, and research.

Community screening for dementia: the Mini Mental State Exam (MMSE) and Modified Mini-Mental State Exam (3MS) compared.

The objectives of this study were to assess whether Teng's modification of the Mini-Mental State Examination (MMSE) improves its performance as a screening test for cognitive impairment and dementia, and to replicate this comparison in French and English language groups, and for differing assumptions concerning the relative importance of false negative and false positive errors. Screening interviews were conducted with representative samples of people aged 65 or over, set in 36 communities in 10 Canadian provinces. There were 8900 community participants in the Canadian Study of Health and Aging, of whom 1600 also underwent an extensive clinical and neuropsychological examination. Sensitivity, specificity and areas under the receiver operating characteristic (ROC) curve for the original MMSE and modified version (the 3MS) were the main outcome measures. Results are reported for French and English versions of the tests. The results indicate the alpha internal consistency for the 3MS was 0.87, compared to 0.78 for the MMSE. The area under the ROC curve in identifying dementia was 0.93 for the 3MS and 0.89 for the MMSE (p < 0.001). There was less difference between the two tests in identifying all levels of cognitive impairment (AUC 0.80 versus 0.77, p < 0.01). The superiority of the 3MS appears more due to its extended scoring system than to its additional questions. The validity of the MMSE was comparable in English and French samples; results for the 3MS were inconsistent between the two samples, suggesting possible translation problems. In conclusion, the 3MS was superior to the MMSE, justifying the slightly greater burden for its administration and scoring. Neither test worked well in identifying lower levels of cognitive impairment.

In-vitro modelling of the bactericidal activity of teicoplanin versus flucloxacillin as used in surgical prophylaxis, against Staphylococcus aureus.

The bactericidal activities of teicoplanin and flucloxacillin in a 50:50 mixture of human serum and Iso-sensitest broth were compared in an in-vitro pharmacokinetic model, at serum concentrations present during surgical prophylaxis. The bactericidal activity of teicoplanin with and without serum was also compared. Six strains of Staphylococcus aureus were tested. The bactericidal rate of teicoplanin in serum was significantly lower than the rate in broth alone. However, there was no significant difference in the bactericidal rates in serum of teicoplanin compared with flucloxacillin, an antibiotic which is commonly used as prophylaxis for certain surgical procedures.