PubMed Health⌕ Search

Biomedical subjects

L Nyström

Publications and source records attributed to L Nyström.

At least 91 records · Page 5Linked to original sources
PubMed1996

The Swedish randomised mammography screening trials: analysis of their effect on the breast cancer related excess mortality.

OBJECTIVE: To apply an indirect method for estimation of the breast cancer related excess mortality in the Swedish randomised mammography screening trials. SETTING: Randomised trials on mammography screening have, in Sweden, been performed in the counties of Kopparberg (W) and Ostergötland (E), the so called WE study, and in the three largest cities in Sweden, Stockholm (southern part), Gothenburg, and Malmö. An overview of the trials was presented in the Lancet in 1993 and included 156,911 women in the invited group and 125,866 in the control group. METHODS: The excess mortality in the breast cancer subgroups was estimated by indirect standardisation using official national cause of death statistics according to Statistics Sweden as a reference. RESULTS: The estimated reduction of the breast cancer related mortality was 24% for the whole group (40-74 years at randomisation). The corresponding figures for the age groups 40-49, 50-59, and 60-69 years were 6%, 28%, and 34% respectively. CONCLUSION: The results are very similar to those presented earlier based on the traditional comparison of the breast cancer mortality in the invited and in the control group. This analysis further strengthens previous reports on a beneficial effect of mammography screening, which is especially pronounced in the age group 50-69.

Adult↗
PubMed1996

A sero-epidemiological cross-sectional study of hepatitis B virus in Zimbabwe.

OBJECTIVE: To estimate the prevalence of hepatitis B viral markers. DESIGN: A sero-epidemiological community-based cross-sectional study. SETTING: All nine provinces of Zimbabwe. PARTICIPANTS: From April 1989 to December 1991 serum samples were collected from 1,461 males and 1,933 females in the age group 10-61 years, the majority in the younger age groups. MAIN OUTCOME MEASURES: Sera were tested for hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), antibody to HBs-Ag (anti-HBs), antibody to hepatitis B core antigen (anti-HBc) and antibody to hepatitis B e antigen (anti-HBe). All sera were tested for HBsAg, anti-HBs and anti-HBc but for the detection of HBeAg and anti-HBe, only samples positive for HBsAg were examined. MAIN RESULTS: The male-to-female ratio in rural and urban settings was 0.82 and 0.66 respectively. The median age for males and females in rural areas was 21 and 22 years and 28 and 26 years respectively in urban areas. The overall prevalence of HBsAg was 15.4% (males 16.8%, females 14.3%). The difference between sexes was consistent in all age groups and statistically significant (P < 0.05). The prevalences in urban and rural areas were almost identical (15.7% v. 15.3%). However, the prevalence was significantly higher among males in the age group 40-49 years in urban areas compared with rural areas (P < 0.0001). Using the case-referent approach, with HbsAg-positive patients as cases and HBsAg-negative ones as referents, the crude odds ratio for rural areas compared with urban areas was 0,97. However, standardisation for year of data collection and province resulted in a relative risk of 2.0, i.e. the risk of being HBsAg-positive in rural areas is twice as high as in urban areas. Similarly, the crude odds ratio for females compared with males was 0.83, and was reduced significantly to 0.7 when standardised for year of data collection and province. The prevalences of HBeAg, anti-HBe, anti-HBs and anti-HBc were 25%, 25%, 45% and 36% respectively. The prevalences of anti-HBs and anti-HBc increased continuously with age and were about 70% higher in the age group 50 years and above compared with those under 20 years. The prevalence of any of the HBV markers-HBsAg, or anti-HBc -was 66% in males and 61% in females. CONCLUSIONS: The results indicate that hepatitis B is hyperendemic in both rural and urban areas of Zimbabwe.

Adolescent↗
PubMed1995

Intrauterine death and infections during pregnancy.

OBJECTIVE: To elucidate whether microbial infections are involved in the etiology of intrauterine death. METHODS: One hundred four cases of stillbirth of unknown etiology and 96 age- and parity-matched referents with live births were analyzed with respect to microbial infection by cultures from the placenta, endocervix and internal organs of the fetuses, external sites of the babies and fetuses, and by serology for bacteria, viruses and Toxoplasma gondii. RESULTS: In 17 cases in whom no other infectious agent was diagnosed, Escherichia coli was isolated from the placenta and one or more internal fetal organs. Tests for Treponema pallidum and Toxoplasma gondii were more frequently positive in cases than in referents (O.R. 8.3 and 3.9, respectively). There was no increased risk for intrauterine death in women with human immunodeficiency virus, cytomegalovirus, herpes simplex virus or rubella virus. CONCLUSIONS: Our findings indicate that infections remain an important cause of intrauterine death in Zimbabwe.

Case-Control Studies↗
PubMed1995

Determination of cause of death among breast cancer cases in the Swedish randomized mammography screening trials. A comparison between official statistics and validation by an endpoint committee.

Between 1976 and 1982, four randomized mammography screening trials started in five screening centres in Sweden, involving 282,777 women (156,911 invited and 125,866 controls) with the aim to study if invitation to screening reduced the breast cancer mortality. An overview of the trials was performed to reduce the confidence intervals for the relative risk estimates. All 1,296 deaths occurring in women with breast cancer detected after randomization were evaluated by an independent endpoint committee (EPC), consisting of four physicians who reviewed collected medical information that was blinded regarding mammography screening. If there was disagreement between the EPC members at the initial individual evaluation the final classification was made at consensus meetings. In only 6.9% (n = 89) of the cases was there disagreement as to whether breast cancer was or was not the underlying cause of death. It was also found that 'breast cancer as underlying cause of death' and 'breast cancer as underlying or contributory cause of death' according to Statistics Sweden resulted in relative risk estimates very similar to those based on the classification by the EPC. The study thus supports the use of official health statistics in the evaluation of randomized breast screening trials in Sweden.

Adult↗
PubMed1995

Anaemia in pregnancy: perceptions of patients in Dar-es-Salaam.

This study was performed to assess the pregnant women's knowledge and attitudes towards anaemia, its causes, prophylaxis, and treatment and to describe existing problems with interventions for anaemia in antenatal clinics. A total of 310 women were interviewed from three MCH-clinics in suburban Dar-es-Salaam. Anaemia was considered a major problem by 88% and 75%, respectively in the two peripheral MCH clinics, but by only 44% of attenders in the hospital MCH clinic. Over 85% of interviewees were aware of the causes of and ways of preventing anaemia. The most frequently mentioned cause of anaemia were related to nutrition while intestinal parasites was mentioned by a few women. Only 5% believed that anaemia might not be dangerous for the mother. In all three clinics more than 90% were aware of the advantages of early booking for antenatal care. None of the mothers had received any ferrous supplements during the current pregnancy, and only a minority (38%) in the previous pregnancy though 40% of them said they were informed they had anaemia in the previous pregnancy. Side effects were not reported as a reason for non-compliance. Thus, mothers were aware that anaemia is a health problem in pregnancy. They would accept effective intervention if they were offered them. The irregular and inadequate supply of haematinics to antenatal clinics is a far more important obstacle to the implementation of the anaemia prevention programme than the knowledge and attitudes of the mothers.

Adult↗
PubMed1994

A note on some identification problems arising in roentgen stereo photogrammetric analysis.

When studying skeleton movements by using implanted landmarks and Roentgen stereo photogrammetric analysis (RSA), some identification problems arise. One is to put the same label on a landmark at different examinations, another is to use the correct pairs of landmark images in order to compute a correct three-dimensional position of each landmark. We will present some methods that can be used as a support for solving these problems. We will also show how it is possible to detect and exclude landmarks that are loose and landmarks that have large measurement errors in their positions.

Algorithms↗
PubMed1994

Epidemiology of respiratory symptoms, lung function and important determinants. Report from the Obstructive Lung Disease in Northern Sweden Project.

SETTING: Cross-sectional epidemiological study based on a representative sample of the general population in northern Sweden. OBJECTIVES: To assess the prevalence of respiratory symptoms, the role of respiratory symptoms as indicators of impairment of lung function, and to define risk factors for respiratory symptoms and lung function impairment. DESIGN: The 1340 subjects of 6610 who reported respiratory symptoms suggestive of asthma or chronic bronchitis in a postal questionnaire study were invited to a structured interview and lung function tests. A control group of 315 subjects was also invited. Risk factors were assessed from the postal questionnaire. RESULTS: 400 subjects in the symptomatic group had attacks of breathlessness and wheezing, while none in the control group had them, corresponding to 7% of the original study population. Chronic productive cough was present in 537 subjects, of whom 13 were from the control group, suggesting that 12% of the original study population had this symptom. Persistent wheeze was the symptom that predicted the greatest proportion of cases of impaired lung function. Attacks of breathlessness, wheezing, long-standing cough and sputum production were all related to age, smoking and a family history of asthma. Both chronic productive cough and impaired lung function correlated strongly with smoking and age, and their prevalences differed in different socio-economic groups. CONCLUSION: Impaired lung function can be predicted from respiratory symptoms. Data collected in postal questionnaires suffice for the identification of risk factors. Combinations of symptoms gave greater odds ratios than individual symptoms.

Adult↗
PubMed1994

Prevalence of positive skin prick tests, allergic asthma, and rhinoconjunctivitis in teenagers in northern Sweden.

The prevalence of positive skin prick tests (SPT) for common allergens and symptoms of allergic rhinoconjunctivitis or asthma was investigated in Umeå in northern Sweden in 1987. Skin prick tests with 10 allergens common in Sweden and a questionnaire were used to examine 1112 teenagers. All subjects with a positive skin prick test or symptoms were interviewed, and they were further investigated by a serum specific IgE test, a ventilatory lung function test, and a physical examination. At least one skin prick test was positive in 43% of the subjects. Ninety-three percent had at least one positive skin prick test to one of the three most common allergens: cat, timothy grass, and birch. The prevalence of current allergic rhinoconjunctivitis was 17%, current allergic asthma 2.8%, and current asthma (both allergic and nonallergic) 6.8%. Multiple logistic regression analysis showed that the most important risk factors for current asthma were sex (being a girl) and atopy. Heredity of asthma or rhinoconjunctivitis and being born in the winter (October-March) also increased the risk. In atopic subjects, having a mother who smoked and heredity of asthma increased the risk. For allergic rhinoconjunctivitis, heredity increased the risk of getting rhinoconjunctivitis.

Adolescent↗
PubMed1994

An incident case-referent study of stillbirths at Harare Maternity Hospital: socio-economic and obstetric risk factors.

This incident case-referent study was conducted at Harare Maternity Hospital in 1989-1990 on 104 consecutive cases of stillbirth with unknown aetiology and 96 age- and parity-matched referents. Information was collected by interviewing the women following a standardized form and by review of antenatal cards. None of the women refused to participate. The most significant obstetric risk factors were prevalence of earlier stillbirths (odds ratio, OR = 6.1) and miscarriages (OR = 4.8). Low height and body mass index also increased the risk of having a stillborn baby significantly as well as a history of flue-like illness during pregnancy (OR = 4.6). The latter may have stimulated the women to book early causing the unexpectedly high OR for early booking among these cases. The pattern for the socio-economic risk factors was not easy to interpret. The most striking finding was the U-shaped relationship between socio-economic status and stillbirths with a higher risk among those with low and high status.

Adolescent↗
PubMed1994

Recognition of risk factors in pregnancy among women attending antenatal clinic at Mbagala, Dar es Salaam.

A study on the recognition of risk factors in pregnancy by pregnant women attending antenatal clinic (ANC) at Mbagala, Dar es Salaam, Tanzania was done. 203 women with ages ranging from 15-43 years were seen on their first visit. 32.51% were primigravidas while 67.5% were multiparous with parity varying from 2-13 deliveries. 32.5% had received no formal education; 13.4% had 1-6 years education, while 54.2% had 7-12 years of formal education. Most of the women did not know when in the course of pregnancy they should start ANC: 52% of the women booked and reported that the best gestational age for booking was in the second trimester. There was no definite answer as to why the women came for the 1st visit to the ANC at a particular gestational age. 5% of the women felt that a woman could start to have children between age 10-14 years. 62.1% thought a woman could start to have children between 15-20 years. 10.3% did not know when a woman could start to have children. Some of the risk factors identified at the clinic included: shortness, age below 19 (11.8%), age 35 and more than 4 deliveries (13.3%) and HB below 75%, malaria and hookworm (9.9%). It appears that pregnant women attending Mbagala ANC booked within the second and third trimester. Their knowledge regarding risk factors in pregnancy was very low. A comprehensive antenatal intervention programme should be introduced at Mbagala ANC to educate women on risk factors in pregnancy. It should be conducted through client oriented problem and need approach.

Adolescent↗
PubMed1994

Female mortality in reproductive ages in Dar es Salaam, Tanzania.

An audit of all cases of female mortality in the reproductive age groups has been performed in Dar es Salaam during 1991-93. Multiple sources of information was used to collect information on deaths. None of the sources of information on death was alone adequate. 73% of the interviews was done at home. The mother or another close relative was interviewed in more than 70% of the cases. A total of 645 deaths were identified and 18% of these were related to pregnancy. Fever, shortness of breath and weight loss were the most common symptoms before death followed by pallor and vomiting. Almost 90% visited a health facility before death. AIDS (27%), tuberculosis (13%) and malaria (12%) were the most common causes of death. Diagnosis could not be made from audit data in 22 cases, and the relatives attributed 7.6% of all deaths to witchcraft or just God's will. AIDS and related diseases are now a major cause of death in the female reproductive age group. There is need to identify preventive measures of this disease as well as prevention of malaria and tuberculosis.

Adolescent↗
PubMed1993

Breast cancer screening with mammography: overview of Swedish randomised trials.

Despite encouraging results from screening trials the efficacy of mammography in reducing mortality remains somewhat controversial. Five studies have been done in Sweden. This overview, based on 282,777 women followed for 5-13 years in randomised trials in Malmö, Kopparberg, Ostergötland, Stockholm, and Gothenburg, reveals a 24% (95% confidence interval 13-34%) significant reduction of breast cancer mortality among those invited to mammography screening compared with those not invited. To avoid the potential risk of differential misclassification causes of death were assessed by an independent end-point committee after a blinded review of all fatal breast cancer cases. The mortality reduction was similar, irrespective of the end-point used for evaluation ("breast cancer as underlying cause of death" or "breast cancer present at death"). There was a consistent risk reduction associated with screening in all studies, although the point estimate of the relative risk for all ages varied non-significantly between 0.68 and 0.84. The cumulative breast cancer mortality by time since randomisation was estimated at 1.3 per 1000 within 6 years in the invited group compared with 1.6 in the control group. The corresponding figures after 9 years are 2.6 and 3.3 and after 12 years 3.9 and 5.1. The largest reduction of breast cancer mortality (29%) was observed among women aged 50-69 at randomisation. Among women 40-49 there was a non-significant 13% reduction. In this younger age group cumulative breast cancer mortality was similar in the invited and control group during the first 8 years of follow-up. After 8 years there was a difference in favour of the invited women. There was no evidence of any detrimental effect of screening in terms of breast cancer mortality in any age group. Among women aged 70-74 years screening seems to have had only a marginal impact.

Adult↗
PubMed1993

An interview study to estimate prevalence of asthma and chronic bronchitis. The obstructive lung disease in northern Sweden study.

A questionnaire of respiratory symptoms and diseases completed by 6610 adults in 3 age cohorts (35-36 y; 50-51 y and 65-66 y) in northern Sweden was followed-up by interview and lung function testing of 1243 subjects with asthmatic or bronchitic symptoms and 263 subjects assessed from the postal questionnaire as being healthy. We report the results of this follow-up study. According to the criteria used, 292 subjects (5.1% of the original study sample) were diagnosed as having asthma. Out of the 1243 subjects 334 (5.9% of the original study population) were diagnosed as having chronic bronchitis. However, examination of the 263 subjects who were healthy according to the postal questionnaire showed that elderly smokers, in particular, under-reported bronchitic symptoms; taking this into account, the prevalence of chronic bronchitis is estimated to be of the order of 9%. Diagnostic difficulties were noted in 70 subjects (corresponding to 1.2% of the original study sample) in whom asthma or chronic bronchitis were strongly suspected. Further investigation of these subjects was considered necessary. In this cross-sectional study, FEV1 < 80% of predicted values was found in 36% of subjects diagnosed as having asthma and in 31% of those with chronic bronchitis. Among subjects with attacks of breathlessness and wheezing, diagnostic criteria often used for asthma in questionnaire studies, 70% were diagnosed as having asthma. Of those with chronic productive cough, 62% were diagnosed as having chronic bronchitis. We consider that trained nurses provide reliable data that may be used in epidemiological surveys of obstructive lung diseases.

Adult↗
PubMed1993

Maternal mortality in rural and urban Zimbabwe: social and reproductive factors in an incident case-referent study.

A community-based incidence case-referent study was undertaken in a rural and an urban setting in Zimbabwe in order to define risk factors associated with maternal deaths at family, community, primary and referral health care levels. Referent subjects were drawn from place or area of delivery for each consecutive maternal death. Using a multiple source confidential reporting network for all maternal deaths, the maternal mortality rate for the rural setting was 168/100,000 live births and that for the urban setting was 85/100,000 live births. A model for interacting factors contributing to maternal mortality was designed. Haemorrhage and abortion sepsis were the major direct causes while malaria was the leading indirect cause in the rural setting. In the urban setting, eclampsia, abortion and puerperal sepsis were the leading causes of maternal deaths. It was found that all situations associated with diminished, or absent social support, that is, being single (Odds Ratio = 4.7, 95% CI = 2.2-9.8) divorced, widowed, one of several wives, cohabiting, or self-supporting carried an increased risk for maternal mortality, especially in the rural area. Income and level of education for index and referent subjects were comparable, probably because of the limited part of the population under study that belonged to a more affluent class. Distribution of cases and referents by religious-affiliation was also comparable. Age > 35 years and parity > 6 were significant risk factors for maternal mortality in the rural setting, whereas bad reproductive history with reported stillbirth or abortion constituted a high risk both in the city and in the rural areas (Odds Ratios 4-6).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Diesel exhaust exposure and smoking: a case-referent study of lung cancer among Swedish dock workers.

We studied 50 lung cancer cases and 154 matched referents, all dock workers, for whom we obtained smoking information and employment histories. We assessed exposures from information on annual diesel fuel consumption from each of the 15 ports included. We used a smoker/nonsmoker term and three exposure variables (machine time, cumulative fuel, and exposed time with fuel consumption above a minimum cutpoint) in the analyses, with three categories for each exposure variable. Odds ratios (ORs) for medium and high exposure groups are consistently higher than reference (low), with an increasing exposure-response trend that is most marked for the exposed time variable (ORs: low = 1.0; medium = 1.6; high = 2.8). When smoking and that exposure variable are simultaneously included in the analyses, odds ratios for the medium (OR = 2.7) and high (OR = 6.8) levels of exposure increase, as does the odds ratio for smoking. Separating smokers and nonsmokers, with the low exposed nonsmokers as the common reference category, the odds ratios are 1.6 (medium) and 2.9 (high) for the nonsmokers, and 10.7 (medium) and 28.9 (high) for smokers. These results indicate an independent effect of diesel exhaust exposure and a strong interaction between smoking and diesel exhaust.

Humans↗
PubMed1993

Comparison of four commercial enzyme-linked immunosorbent and one agglutination assays for the detection of HIV antibodies in sera from Zimbabwe.

Sera from 871 AIDS and AIDS related complex patients were used to evaluate four ELISA and one agglutination assays. Commercial tests compared were Abbot, Wellcoyzyme, Biotest, Du Pont and Serodia. Wellcozyme and Serodia had the highest sensitivity (96.8 pc and 98.8 pc respectively) but the lowest specificity (53.3 pc and 46.5 pc respectively). Du Pont was the least sensitive test (89.1pc). Biotest and Abbot were comparable--Biotest had a higher sensitivity (93.2pc as compared with 90.6pc) but Abbot had a higher specificity (94.1 pc as compared with 89.1 pc). Thus, Abbott and Biotest both had a satisfactory high sensitivity and specificity and could thereby be recommended for use in screening of HIV-1 antibodies in south east Africa.

AIDS-Related Complex↗
PubMed1993

High prevalence of asthma and related symptoms in teenagers in northern Sweden.

Recent reports have suggested an increased asthma prevalence in the Nordic countries. The prevalence of asthma and related symptoms from lower airways in Umeå, Northern Sweden, was investigated in 1987. We used a questionnaire and a skin prick test in 1,112 teenagers. Individuals with symptoms or positive skin prick tests were examined further. The clinical examination included an interview, a ventilatory lung function test, serum specific immunoglobulin E (IgE) test, and a physical examination. Individuals with symptoms from the lower airways underwent a methacholine inhalation test. Asthma was defined as recurrent attacks of dyspnoea and/or wheezing, triggered by known stimuli (excluding infections), and at least one of the following: signs of obstructive airways at examination or provocation concentration giving a 20% fall in forced expiratory volume in one second (PC20) < 8 mg.ml-1. Using this definition, the prevalence of asthma was 6.8%, with a significantly higher prevalence in girls (9.6%) than in boys (4.1%). Furthermore, 16.4% had dyspnoea, wheeze or prolonged cough but did not fulfil our criteria for asthma. The prevalence of asthma and of symptoms from lower airways is higher than has previously been found in Sweden.

Adolescent↗