Swedish Trials Research Articles

Microbiological and serological diagnosis of pertussis.

Swedish vaccine trials have been used to examine sensitivity and specificity of diagnostic procedures for Bordetella pertussis infection. The proportions of cases diagnosed by culture and serology were 55% and 45%, respectively, when both methods were optimized. The culture method included nasopharyngeal aspiration, direct inoculation on plates, enrichment, and repeated collection of samples. An enzyme-linked immunosorbent assay for IgG antibodies to pertussis toxin (PT) and to filamentous hemagglutinin, with paired sera, was used for serology. Preexposure sera other than the acute serum increased the sensitivity of serology by 10%. A serology quality-assurance program to control imprecision and allow comparability over time and between laboratories is described. The direct fluorescent antibody technique had a sensitivity of 38% and a specificity of 99.6% in comparison with culture. A nested polymerase chain reaction (PCR) with the PT promoter region as target was 95% sensitive in comparison with culture if a cation-exchange resin was used to reduce inhibition. PCR enabled us to identify 83 positive samples in addition to 215 culture-positive ones-an increase of 38%--all with other indicators of pertussis infection.

Levels of anti-pertussis antibodies related to protection after household exposure to Bordetella pertussis

Vaccine efficacies against typical pertussis after household exposure to Bordetella pertussis were estimated to be 75.4% for an acellular five-component vaccine, 42.4% for an acellular two-component vaccine, and 28.5%, for a licensed US whole cell vaccine, compared to placebo. Logistic regression analyses demonstrated statistically significant correlations between clinical protection and the presence of IgG antibodies against pertactin, fimbriae 2 3 and pertussis toxin in pre-exposure sera. Multicomponent pertussis vaccines of proven high efficacy in recent Swedish NIAID-sponsored efficacy trials induced higher antibody levels against pertactin and fimbriae 2 3 than less efficacious vaccines. Anti-pertactin, anti-fimbriae 2 3 , and anti-PT may be used as surrogate markers of protection for multicomponent acellular and whole-cell vaccines against pertussis.

Rationale for Annual Screening Mammography for Women Ages 40–49 Years

Proof of the benefit for mammographic screening of women ages 40-49 years is now available. Randomized controlled trials (RCTs) conducted in Gothenburg and Malmo, Sweden have shown statistically significant breast cancer mortality reductions of 36% and 45% respectively. A meta-analysis of all five Swedish trials has found a statistically significant mortality reduction of 29% for woman in this age group. Substantially greater reductions in mortality would likely have resulted if women in these trials had been screened annually. Because the benefits are substantial, and the risks from screening are relatively small and acceptable, screening mammography beginning at age 40 is now recommended by the American Cancer Society, as well as the National Cancer Institute.

Benefits of Screening Mammography: A Review for the Primary Care Physician

Screening mammography, particularly for women in their 40s, has become a confusing issue for many physicians. Recent scientific and political controversies regarding screening guidelines have added to this confusion. Many randomized clinical trials have shown the benefits of mammographic screening for women over the age of 50, and recent studies show a statistically significant benefit for women in their 40s as well. Understanding the screening controversy requires an understanding of the principle of screening for disease, the epidemiology of breast cancer, and the results of the many randomized clinical trials, particularly recent data from the Swedish two-county trials. An appreciation of the improvements in mammographic quality in recent years, and in the education of the radiologists who interpret these studies, will also heighten clinical acceptance of this screening technique. Both the American Cancer Society and American College of Radiology endorse annual mammographic screening for women over age 40, and there is compelling evidence to support these recommendations. Radiologists, primary care providers, surgeons, and pathologists should work together to enhance the benefits of and access to screening mammography.

Cost-benefit analysis in mammography screening

The Swedish Mammography-Screening trials have shown a long-term reduction in the mortality rate in women aged between 50-69 of up to 30%. The lower reduction in mortality observed in women aged 40-49 was not statistically significant. Long-term observation over 20 years) has shown that a radiation dose of 2.4 mGy for a 2-view-mammography per breast does not lead to an increase in occurrence of breast cancers. The advantage of screening with regard to a reduction in death rate, frequent use of breast cancerving therapy and the reduction by half in the average size of the tumor compared to control groups results in: A recommendation for quality controlled screening in Germany from the age of 50 to 70. The possible advantage for younger women must be examined in further trials. Screening in the form of a de-centralized check-up system is to be carried out by practising doctors in co-operation with hospitals which will be responsible for double findings, assessment of difficult cases and continuous cost evaluation. Quality assurance centres, reference and training centres are required. The mammography in curative check-ups will also benefit from a screening programme.

Quantitative Interpretation of Age-Specific Mortality Reductions From the Swedish Breast Cancer-Screening Trials

Results from five Swedish randomized trials may provide the most conclusive evidence on the effect of mammographic screening and have been used to forecast the expected reduction in breast cancer mortality in other programs. However, those trials demonstrated different degrees of reduction. The interpretation of observed mortality reduction after long follow-up for women aged 40-49 years at trial entry is both important and controversial. We estimated what percentage of the observed mortality reduction for women aged 40-49 years at entry into the five Swedish screening trials might be attributable to screening these women at 50 years of age or older. Moreover, we calculated the most likely percentage mortality reduction for specific screening programs if the Swedish results were generalized and analyzed whether characteristics of each trial might at least partly explain the observed differences in reductions among the trials. Each Swedish trial was simulated with one underlying computer simulation model (MISCAN--MIcrosimulation SCreening ANalysis) of the natural history of the disease and the performance of screening, taking into account nine important trial characteristics. Improvement in prognosis for screen-detected case patients was estimated with age-specific reduction for all trials and each trial design as a reference. An expected 7% reduction in breast cancer mortality for women aged 40-49 years at trial entry (relative risk [RR] = 0.93) was determined by computer modeling, assuming no improvement in prognosis for cancers that are screen detected before 50 years of age. This result indicates that, of the overall 10% observed reduction (RR = 0.90) in the five Swedish trials analyzed, most (70%) of this reduction might be attributable to screening these women in later rounds after their 50th birthday. Using additional trial information, predictions of breast cancer mortality reduction in women 50 years or older might be 11% larger than previously expected, assuming that high-quality mammographic screening can be achieved in nationwide programs. For women aged 50-69 years at trial entry, the differences in expected versus observed mortality reduction among the trials are estimated to be relatively small. (Expected mortality reductions range from 24% to 32%). Results from the Swedish randomized breast cancer-screening trials should be seen as more favorable regarding the effect of mammographic screening in reducing breast cancer mortality for women aged 50-69 years than was estimated earlier. Our analyses also suggest that the improvement in prognosis due to screening for women aged 40-49 years is much smaller than that for women aged 50 years or older. Approximately, 70% of the 10% observed reduction in breast cancer mortality (i.e., 7%) for women aged 40-49 years at trial entry might be attributable to a reduction due to screening these women after they reach age 50. Detailed screening data for the 40- to 49-year age group of all Swedish trials should be analyzed to specifically estimate the natural history and performance of screening in this age group.

Sulphur deficiency in oilseed rape and cereals ‐ Experience from Swedish field trials

AbstractField trials in Sweden have shown responses to S‐fertilizers by rapeseed, but not by barley. These responses varied from 0 to approximately 200 kg/ha seed. They are, however, hard to predict and the criteria of S availability have to be elucidated.

ABC of Breast Diseases: Screening for Breast Cancer

Lack of knowledge of the pathogenesis of breast cancer means that primary prevention is currently a distant prospect. Screening represents an alternative approach to try to reduce mortality from breast cancer. The aim of screening is to detect breast cancer when it is small and before it has had the chance to spread There is no evidence that clinical examination, breast ultrasonography, and teaching self examination of the breast are effective tools in screening for breast cancer. Randomised controlled trials have shown, however, that screening by mammography can significantly reduce mortality from breast cancer. Mortality can be reduced by up to 40% in women who attend for screening, and the benefit is greatest in women aged over 50. Recently published data from the combined Swedish trials showed an overall reduction in breast cancer mortality of 29% during 12 years of follow up in women aged over 50 who were invited to attend screening and a 13% reduction in younger women. Screening tests should be simple to apply, cheap, easy to perform, easy and unambiguous to interpret, and able to identify women with disease and exclude those without disease. Mammography is expensive; it requires high technology machinery, special film and dedicated processing, and highly trained radiologists to interpret the films; and it detects only 95% of all breast cancers. It is, however, the best screening tool available for detecting breast cancer and is the only screening method for any malignancy which has been shown to be of value in randomised trials. Summary of 7–12 years mortality data from randomised trials of breast cancer screening. Points and lines represent absolute change in mortality and confidence interval. Over 70% of the target population must accept the invitation to participate if a screening programme is to significantly reduce mortality. If fewer participate the costs …

Cost‐effectiveness of mammographic screening in Australia

The purpose of this research was to estimate the cost-effectiveness of mammographic screening to supplement the results of the National Evaluation of Breast Cancer Screening which identified the mortality benefit as the most sensitive parameter. This appraisal used a different computer model, MISCAN, which models the effects of introducing a national screening program into a previously unscreened population, rather than basing estimates on the assumption of a fully established program. For the 40 to 49 age group a mortality reduction of 8 per cent was assumed, rather than the 30 per cent estimate utilised in the National Evaluation. The revised estimate is based on the two Swedish trials (Malmo and WE). New estimates for treatment costs were also incorporated into the MISCAN model. The cost-effectiveness of the policy recommended in the National Evaluation Report, $11,000 per life year saved with two-yearly screening of women over 40, is estimated by the MISCAN model to be $20,300. These differences arise partly from the difference in mortality effects for the 40 to 49 age group, but also from differences inherent in the steady-state and dynamic population approaches to modelling premature deaths averted. The MISCAN results confirm that screening for women over 50 is more cost-effective than screening women under 50. Screening all women aged 50 to 69 every two to three years is reasonable value for money. For women aged 40 to 49 the mortality benefit and cost-effectiveness is less clear, and it would be prudent to allow screening in this group until further evidence is available.

Breast cancer screening and cost‐effectiveness; Policy alternatives, quality of life considerations and the possible impact of uncertain factors

Mammographic screening for women aged 50-70 is effective in reducing breast cancer mortality, but the impact on quality of life and the attainable mortality reduction remain to be discussed. The consequences of expanding screening programmes to include women in other age groups are uncertain. We have predicted the effects and costs for 5 popular screening variants, differing in age group and screening interval, on the basis of our analysis of the Dutch screening trials and of the reported mortality reductions in other trials. We have also investigated the influence of a large number of uncertain factors. Screening for women aged 50 and over with a 2- or 3-year interval is very cost-effective and will result in reductions of respectively 16% or 10% in breast cancer mortality in a real population. Variation of most variables keeps the cost-effectiveness (CE) ratio limited to the range of US $3,000 to 5,000 per life-year gained. A 2- to 3-fold change in CE ratio would only occur if the extreme estimates of mortality reduction in the Swedish screening trials were applied. The impact on quality of life (QoL) is limited: for the 2-yearly screening policy for women aged 50-70, the cost per Quality-Adjusted Life-Year (QALY) gained is 4,050, whereas the cost per life-year gained is US $3,825. The CE ratio for 2-yearly screening of women aged 40-70 is 5,400, but the additional cost per additional life-year gained is US $35,000. It would be preferable by far to extend the screening programme to women over the age of 70 or to shorten the screening interval for women aged 50-70. Screening performances, the demand for mammograms outside screening and the possibility of a survival improvement irrespective of screening have a strong impact on QoL and CE.

A model for estimating crop yield losses caused by soil compaction

A computerized empirical model for estimating the crop yield losses caused by machinery-induced soil compaction and the value of various countermeasures is presented, along with some examples of estimations made with it. The model is based mainly on results of Swedish field trials, and predicts the effects of compaction in a tillage system that includes mouldboard ploughing. It is designed for use at farm level and predicts four categories of effects: (1) Effects of recompaction after ploughing. The calculations are based on the wheel track distribution in the field and the relationship between “degree of compactness” of the plough layer and crop yield. (2) Effects of plough layer compaction persisting after ploughing. Crop yield losses are estimated from traffic intensity in Mgkm ha −1 (Mgkm = the product of the weight of a machine and the distance driven), soil moisture content, tyre inflation pressure and clay content. (3) Effects of subsoil compaction. The calculations are similar to those presented under point (2), but only vehicles with high axle load are considered. These effects are the most persistent. (4) Effects of traffic in ley crops. The estimations are based on wheel track distribution, soil moisture content and several other factors.

A dissent from dr schmidt's appraisal of evidence on breast cancer screening

This commentary on Dr Schmidt’s paper, “The epidemiology of mass breast cancer screening-a plea for a valid measure of benefit” [1], was stimulated by my reaction on reviewing the paper when it was submitted for publication. The extensiveness of his analysis of benefits and risks in breast cancer screening called for a detailed assessment of his arguments rather than a dissenting note to the editors, a position with which they agreed. Dr Schmidt probes into published results of the two randomized controlled trials on breast cancer screening in Sweden and draws peripherally on some of the observations in the Health Insurance Plan project to conclude that “even with the assumption that screening can save lives, the net health effect of mass breast screening is questionable and appears to be rather detrimental.” The Swedish trials are the twocounty study in Kopparberg-astergotland [2] and the study in Malmij [3], both of which started in the late 1970s 13-14 years after the HIP trial began. Dr Schmidt’s negative conclusion is based on the observed “excess” in breast cancers detected among study groups of women in the Swedish trials and the additional surgery that results from screening; the small gain when measures of absolute differences between study and control groups in breast cancer mortality are considered instead of relative risk; questionable balance

A Neighbour Model Applied to the Statistical Analysis of Swedish Variety Trials

Abstract 124 variety trials, laid out in randomized incomplete blocks, have been analysed with help of a neighbour model developed for British variety trials. The efficiency of this analysis is compared to those for the incomplete block and complete block analyses respectively. Standard errors for pairwise comparisons between varieties have been reduced by 23% by using the neighbour model compared to using complete blocks. The corresponding figure for incomplete blocks is 14%. While the incomplete block analysis is justified by randomization the neighbour model is based on a (not unreasonable) assumption about the correlation structure between plots in the field. If this assumption is true, further improvements are possible by using special designs.

Vibriosis vaccination of rainbow trout Salmo gairdneri at varying temperatures and seasons. II. Effects on antibody production in five Swedish field trials

Vibriosis vaccination of rainbow trout Salmo gairdneri at varying temperatures and seasons. II. Effects on antibody production in five Swedish field trials

Vibriosis vaccination of rainbow trout Salrno gairdneri at varying temperatures and seasons. I Effects on mortality and feed conversion in four Swedish field trials

Vibriosis vaccine trials were conducted on 4 Swedish brackish water rainbow trout Salmo gairdneri net-pen farms. Intraperitoneal (IP) vaccination of fall- and spring-transport yearlings at 3 to 16 o C provided significant protection against mortalities from Vibrio anguillarum, serotype 1 (VA). Dipvaccination of fingerlings provided only slight protection of limited duration

Swedish interlaboratory trials on proximates and certain macro minerals

During the period 1980–1986 a number of samples representing different kinds of food items were distributed to about thirty laboratories for analysis. The objective was to test the laboratories with respect to their analytical skill in proximate analyses. Towards the end of the period the condition for analyses and the statistical technique had been developed in such a way that variations could be estimated within laboratories (repeatability) as well as between laboratories (reproducibility). An ellipse was constructed so that the probability for a randomly selected laboratory to fall within the ellipse would be 95%. This presentation also gives an example of wether mean values and standard deviations for a specific item change depending on the time between two courses of analysis.

Volume growth and wood density of plus tree progenies ofPinus contortain two Swedish field trials

Seventy‐four half‐sib families of lodgepole pine (Pinus contorta ssp. latifolia Engelm.) plus trees were measured for vigour, height growth, stem diameter, wood density and ring width in two Swedish field trials at age 9. Height growth, wood density and ring width differed between families within provenances with variance components of 3–8 %. Coefficients of variation were highest for height growth and lowest for ring width. Heritabilities were similar for height growth and wood density but lower for ring width. These genetic parameters seemed to be equal for all provenances. Indirect selection for high dry stem biomass was more effective using height growth than wood density, and a correlated response in wood density of 2.1 % of mean by selecting the 15 highest parent trees was indicated. Juvenile wood density looks uncertain as a selection criterion for mature wood density.

The Utilization of Psychiatry in the Armed Forces†

AUTHORS’ SUMMARYThe Internet has revolutionized access to healthinformation and made communication over longdistances easier. This article reviews the use of theInternet for delivery of cognitive behaviour therapy.As a starting point the concept of guided self-helpis introduced. We next present the treatmentapproach and different protocols briefly. Next,Swedish studies on panic disorder, social phobia,and depression are summarized using meta-analytic techniques. Implementation in regularclinical setting is discussed with a focus onefficacy versus effectiveness, training of therapist,combined treatments, and cost-effectiveness. Weconclude that Internet treatment is likely tobecome a treatment option for suitable patientsin the future.IntroductionThe Internet is rapidly spreading as a means tocommunicate, obtain, and exchange information.A substantial proportion of the activity on theInternet is devoted to health issues, and this alsopertains to psychological problems such as anxietyand depression (1). Information technology ingeneral and Internet technology in particularpresent challenges for the health care system.First, patients use the Internet to obtain medicalinformation (2). Second, they might join groupson the Internet for support (3). Third, actualconsultations are being handled from a distancevia the Internet (4). In this paper we will give anoverview of another use of the Internet, namelythe provision of minimal contact psychologicaltreatment for anxiety and depression. As severalstudies in this area have been conducted inSweden, we will mainly focus on the Swedishresearch. However, experiences from Australia,Germany, USA, the Netherlands, and the UKwill be mentioned. A meta-analytic summary ofthe published Swedish controlled trials will beprovided, and a discussion on dissemination,effectiveness, and implications for the training oftherapists will be included.The concept of guided self-helpThe term self-help implies that patients are doingthe treatment on their own with no assistance.A self-help intervention can be defined as apsychological treatment, in which the patienttakes home a standardized psychological treat-ment and works it through more or less independ-ently. In a standardized psychological treatment, apatient can read step-by-step what he can do toapply a generally accepted psychological treat-ment to him- or herself. The standardizedpsychological treatment can be written down inbook form, but it can also be available throughother media, such as a personal computer, CD-ROM, television, video, or the Internet. Contactswith therapists are not necessarily required forthe patient to complete the therapy. If there arecontacts with a therapist, these contacts aremainly supportive or facilitative, are not aimedat developing a traditional relationship betweentherapist and patient, and are only meant tosupport the working through of the standardizedpsychological treatment. It could, however, in-volve guidance on where to seek help and adviceregarding other matters if needed, such as medicalconsultations. Contacts with therapists can be bypersonal contact, by telephone, by e-mail, or anyother communication method. In reality, however,self-help often requires assistance from a therapistor counsellor (5). In many studies on guided self-help this has been in the form of telephone contact(6), but there are also examples of other forms ofsupport, for example by having group meetings.