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Biomedical subjects

A Ekbom

Publications and source records attributed to A Ekbom.

At least 163 records · Page 9Linked to original sources
PubMed1997

Inflammatory bowel diseases: health care and costs in Sweden in 1994.

BACKGROUND: Inflammatory bowel disease (IBD) has highly variable course and severity. Since comprehensive data on its impact are scarce, we analyzed all IBD care and costs in Sweden (population, 8.8 million). METHODS: A cross-sectional observational study, using national registers and surveys on ambulatory care, hospital admissions, medication, sickness leave, and early retirement for IBD in 1994, was carried out. We calculated direct health care costs and indirect 1-year costs caused by morbidity. RESULTS: Ambulatory care was concentrated to specialists in internal medicine at hospitals. One-fourth of the patients accounted for 48% of 1994 hospital admissions. Medication was predominantly aminosalicylates and steroids. Sickness leave episodes were long--on average, 6 weeks. Although uncommon, early retirements lasted 14 years on average. With regard to the underlying prevalence, the use of health care and compensations by Crohn's disease patients was two to four times that of patients with ulcerative colitis. Morbidity took 68% of total costs. Among direct costs, admissions accounted for 58%. Neither complications nor surveillance added much. CONCLUSION: Ulcerative colitis is twice as common as Crohn's disease. In health care use, these roles are reversed. Since morbidity causes two-thirds of the costs, comprehensive analyses, including indirect costs, are necessary when evaluating new diagnostics and therapies.

Ambulatory Care↗
PubMed1997

Clinical course during the 1st year after diagnosis in ulcerative colitis and Crohn's disease. Results of a large, prospective population-based study in southeastern Norway, 1990-93.

BACKGROUND: The clinical course and prognosis in ulcerative colitis (UC) and Crohn's disease (CD) have been described in many studies, mostly retrospective. Such studies are hampered by problems such as inclusion over a long time period, proper definitions, incomplete case records, and outdated methods of diagnosis. In a prospective study we identified 846 patients with inflammatory bowel disease (IBD) over a 4-year period from 1990 to 1993. Uniform diagnostic and therapeutic strategies were used as a basis for later assessment of the short-term clinical course in different subgroups of UC and CD and analysis of potential risk factors for relapse or surgery. METHODS: At the time of follow-up, a mean of 16.2 months after diagnosis, 496 UC patients and 232 CD patients, altogether 98%, were available for evaluation. A colonoscopy was performed in 88% (410 of 465) of the UC patients attending a clinical examination and in 76% (164 of 216) of the CD patients. RESULTS: Eleven patients with UC and five patients with CD died during follow-up, four of complications related to IBD. The cumulative 1-year relapse rate in the remaining patients was 50% for UC and 47% for CD. Of the patients with relapses 11 % of the UC patients and 10% of the CD patients had a chronic relapsing course without any difference with regard to the various disease categories in UC or CD. An increased risk of relapse was found in patients less than 50 years old only in UC. In UC a higher risk for surgery was found in patients with extensive colitis compared with left-sided colitis (P = 0.011), and CD patients with small-bowel involvement had a higher risk of surgery than patients with disease confined to the colon (P = 0.021). There was no excess risk of relapse or surgery in smokers as compared with non-smokers or former smokers, nor did the risk of relapse vary with the level of cigarette consumption in either UC or CD patients. CONCLUSION: The high relapse rate of around 50% for both UC and CD calls for a review of the existing treatment. Further follow-up will be necessary to improve our ability to make clinical decisions relating to medical and surgical treatment options.

Age Factors↗
PubMed1997

Survival and risk of cholangiocarcinoma in patients with primary sclerosing cholangitis. A population-based study.

BACKGROUND: Endoscopic retrograde cholangiopancreatography was introduced in the early 1970s, making a more reliable diagnosis of primary sclerosing cholangitis (PSC) possible. Since then decreased survival and increased risk of cholangiocarcinoma have been reported. However, no population-based studies have quantified these outcomes. METHODS: A population-based cohort of 125 patients with a verified PSC diagnosis was followed up through linkage to the Swedish Death Registry and the Swedish Cancer Registry for occurrence of death and cholangiocarcinoma. RESULTS: The diagnosis of PSC was associated with a substantially decreased survival, with an overall 10-year survival of 68.8%. Patients with a diagnosis of inflammatory bowel disease (IBD) had a somewhat better prognosis, 71.8%, compared with 60% for patients without. Fourteen subsequent cholangiocarcinomas yielded a cumulative risk of 11.2% 10 years after diagnosis. Sex, duration of IBD, and colectomy influenced neither the survival nor the cholangiocarcinoma risk. CONCLUSION: Patients with PSC have a substantially decreased survival, which is most pronounced among patients without IBD.

Actuarial Analysis↗
PubMed1997

Population-based study of cancer risk and relative survival following sphincterotomy for stones in the common bile duct.

BACKGROUND: Endoscopic sphincterotomy was introduced in 1974 as a procedure for removing stones in the common bile duct. To assess the long-term risk of cancer and relative survival, all patients who underwent this procedure at six different hospitals between 1977 and 1985 were identified. METHODS: A total of 992 patients was identified and they were followed by linkage to the Swedish Death Registry and the Swedish Cancer Registry. RESULTS: At 1 year or more after sphincterotomy there was no increased risk of cancer in the liver, gallbladder, bile duct or pancreas (standardized incidence ratio 0.80, 95 per cent confidence interval 0.3-1.9). Relative survival was lowered slightly in the first year after sphincterotomy, but did not differ from that of the background population thereafter. CONCLUSION: Endoscopic sphincterotomy for stones in the common bile duct does not appear to affect the risk of cancer in the pancreas, liver or bile ducts, nor does it affect long-term survival.

Adult↗
PubMed1996

Excess risk of primary liver cancer in patients with diabetes mellitus.

BACKGROUND: Chronic infection with hepatitis B virus, alcohol consumption, and cirrhosis of the liver are recognized risk factors for primary liver cancer. A few, but not all, studies have suggested that diabetes mellitus also increases risk for this cancer. PURPOSE: We conducted a population-based cohort study to analyze the risk of developing primary liver cancer and biliary tract (gallbladder, extrahepatic bile ducts, and ampulla of Vater) cancers among patients with diabetes. METHODS: A cohort of 153 852 patients with a hospital discharge diagnosis of diabetes in the period from 1965 through 1983 was identified by use of the Swedish In-patient Register. Follow-up for these patients extended from the date of cohort entry through December 31, 1989. Incident cases of cancer during follow-up were identified through the Swedish Cancer Registry. To minimize the impact of selection bias, we excluded from the analysis patients who were diagnosed with liver and biliary tract cancers during the first year of follow-up. Standardized incidence ratios (SIRs) and their 95% confidence intervals (CIs) were computed by use of nationwide rates of liver and biliary tract cancers, adjusted for age, sex, and calendar year, for comparison. RESULTS: During 1-24 years of follow-up, 819 incident cancers in the combined category of primary liver (n = 533) and biliary tract (n = 286) were identified in the cohort, yielding an overall SIR of 2.5 (95% CI = 2.3-2.6). The risk was higher in men (SIR = 3.2; 95% CI = 2.9-3.6) than in women (SIR = 2.0; 95% CI = 1.8-2.2). The incidence of primary liver cancer alone was increased fourfold (SIR = 4.1; 95% CI = 3.8-4.5); again, the risk was higher in men (SIR = 4.7; 95% CI = 4.2-5.2) than in women (SIR = 3.4; 95% CI = 2.9-3.9). Smaller increases in risk were seen for cancers of the gallbladder, the extrahepatic bile ducts, and the ampulla of Vater. After exclusion of diabetic patients with concomitant diseases that predispose to primary liver cancer, such as alcoholism, cirrhosis, and hepatitis, the persistence of an approximately threefold excess risk was observed. CONCLUSIONS: Our findings suggest that patients with diabetes are at increased risk of developing primary liver cancer and perhaps cancers of the biliary tract. The mechanisms involved in the association of diabetes and liver cancer remain to be clarified. Additional studies are needed to determine whether patients with insulin-dependent diabetes mellitus and those with non-insulin-dependent diabetes mellitus differ in their risk for primary liver cancer or whether the risk is affected by the type of diabetes treatment.

Adult↗
PubMed1996

Smoking and colorectal cancer: a 20-year follow-up study of Swedish construction workers.

BACKGROUND: Although cigarette smoking has consistently been shown to be positively related to the risk of adenomatous polyp development (benign neoplastic growth of epithelial tissue in the colon), most studies of cigarette smoking and the risk of colorectal cancer have been negative. However, in two large prospective studies in women and men, a statistically significant association between cigarette smoking and an increased risk of colorectal cancer was found, but only after more than 35 years of smoking. PURPOSE: To shed further light on the alleged relationship between long-term smoking and colorectal cancer risk, we performed a retrospective cohort study among Swedish construction workers, with many long-term smokers, complete long-term follow-up, and a large number of observed cases. METHODS: We analyzed the association of smoking with colon cancer and with rectal cancer, using data on a cohort of approximately 135000 male construction workers. High-quality exposure information was collected with the use of a comprehensive questionnaire filled out at the time of enrollment in the cohort, from 1971 through 1975. Complete follow-up was achieved through 1991 and the subjects were observed for an average of 17.6 years, thereby contributing approximately 2375000 person-years of follow-up. We calculated age-adjusted rate ratios (RRs) with the use of Poisson-based multiplicative multivariate models followed by further multivariate modeling that adjusted for other variables. RESULTS: A total of 713 incident colon cancers and 505 rectal cancers were observed. There was no statistically significant association between current smoking status, number of cigarettes smoked or number of years smoking, and risk of colorectal cancer. The age-adjusted RRs were 0.98 (95% confidence interval [CI] = 0.82-1.17) and 1.16 (95% CI = 0.94-1.44) for colon and rectal cancers, respectively, among current smokers, and 1.07 (95% CI = 0.63-1.82) and 1.08 (95% CI = 0.58-2.03) among smokers of 25 or more cigarettes per day, relative to nonsmokers. Among smokers for more than 30 years at the start of follow-up, the age-adjusted RRs were 1.03 (95% CI = 0.85-1.25) and 1.21 (95% CI = 0.96-1.53) for colon and rectal cancers, respectively, relative to nonsmokers. Heavy smokers of cigars and pipes had a statistically nonsignificant tendency toward excess risk for colon cancer, but there was no clear dose-risk trend. CONCLUSION: Our large cohort study did not indicate any excess risk of colon cancer in males who were long-term heavy smokers and provided only weak support for an association with rectal cancer. Our data are thus consistent with the majority of previous reports. The reasons for the discrepancies in comparison with recent U.S. data have yet to be identified.

Adult↗
PubMed1996

A prospective study of smoking and risk of prostate cancer.

We evaluated the hypothesis that smoking increases the incidence of and mortality from prostate cancer. High-quality smoking information was collected in 1971-1975 in a nation-wide cohort of 135,006 male construction workers in Sweden. We achieved virtually complete follow-up through record linkages and ascertained as of December 1991 2,368 incident cases of prostate cancer and 709 deaths due to this disease. Rate ratios (RR) of prostate cancer incidence and mortality, with 95% confidence intervals (CI), were estimated in Poisson-based age-adjusted models, with amount and duration of smoking as independent variables. We found no convincing association between current smoking status, number of cigarettes smoked or years since onset and risk of prostatic cancer. The age-adjusted incidence RR among previous smokers was 1.09 and among current smokers 1.11 compared with non-smokers. Weak and inconsistent trends were seen with increasing number of cigarettes smoked per day and increasing duration among current smokers. Smokers of 15 or more cigarettes daily for at least 30 years experienced an incidence RR of 1.30. Mortality in ex-smokers was similar to that in never-smokers; it was, however, slightly increased among current smokers without any trend with amount smoked or duration. The weak and inconsistent associations between smoking and prostate cancer could easily have arisen due to bias or confounding. We therefore conclude that smoking is most likely not causally linked to the occurrence of prostate cancer.

Adult↗
PubMed1996

Crohn's disease after in-utero measles virus exposure.

BACKGROUND: An epidemiological association between Crohn's disease and measles virus exposure in early life has been suggested in case-control studies. METHODS: To determine absolute risk estimates for in-utero measles virus exposure and Crohn's disease, maternity charts for all 25000 deliveries at University Hospital, Uppsala, between 1940-49 were reviewed: four cases of measles infection in the mother during pregnancy were identified. The children and two of their mothers were interviewed and case records reviewed. Three offspring had undergone multiple intestinal resections; tissue from these cases were examined by routine histology, and for measles-virus nucleoprotein antigen by immunohistochemistry and immunogold electronmicroscopy. FINDINGS: Three of the four children had Crohn's disease. In each the disease was preceded by recurrent, antibiotic-resistant pneumonia. They had extensive ileal and colonic disease; two patients required intravenous feeding. The only offspring to have had measles as a child did not develop Crohn's disease. Measles virus antigen was detected in foci of granulomatous and lymphocytic inflammation in all children with Crohn's disease. INTERPRETATION: The data indicate that exposure of mothers to measles virus in utero is a risk factor for Crohn's disease in their children. Exposure at this time may lead to persistent infection, or modify the response to infection in later life, leading to persistence of measles virus.

Adult↗
PubMed1996

Perinatal characteristics in relation to incidence of and mortality from prostate cancer.

OBJECTIVE: To test the hypothesis that factors causing morbidity and mortality from prostate cancer may operate in utero. DESIGN: Matched case-control study of singleton men born between 1874 and 1946 at one hospital. SETTING: Uppsala University Hospital. SUBJECTS: 250 patients with prostate cancer and 691 controls, including 80 patients who died from prostate cancer and their 196 matched controls. MAIN OUTCOME MEASURES: Mother's age at menarche, parity, pre-eclampsia or eclampsia before delivery, age at delivery and socioeconomic status; case or control's birth length and weight, placental weight, prematurity derived from gestational age, and presence of jaundice. RESULTS: Both pre-eclampsia (odds ratio 0, 95% confidence interval 0 to 0.71) and prematurity (0.31, 0.09 to 1.04) were inversely associated with incidence of prostate cancer. Among subjects born full term, placental weight, birth weight, and ponderal index (weight/height 3) showed non-significant positive associations with prostate cancer incidence, and stronger associations with mortality. CONCLUSION: Prenatal exposures that are likely correlates of pregnancy hormones and other growth factors are important in prostate carcinogenesis and influence the natural course as well as the occurrence of this cancer.

Age Factors↗
PubMed1996

Testicular nonseminoma and seminoma in relation to perinatal characteristics.

BACKGROUND: Testicular cancer incidence peaks during the third decade of life, and an increasing trend in the occurrence of this disease has been seen in many countries. Few risk factors have been established for testicular cancer, but evidence suggests that causal factors operate early in life, perhaps even in utero. PURPOSE: We performed a case-control study to evaluate specific perinatal characteristics as risk factors for the two main histopathologic types of testicular cancer: seminomas and nonseminomas. METHODS: Two hundred thirty-two case patients with invasive testicular cancer and 904 individually matched control subjects (all singleton births), nested in a cohort of men born at 10 hospitals in Sweden from 1920 through 1978, were included in the study. Perinatal information about the study subjects and their parents was obtained from birth records. For the mothers, information was recorded concerning age at menarche, marital status, parity, age at delivery, maternal weight at delivery and at first visit to a maternal-care center, education and/or profession, and any medical problems encountered during pregnancy or after delivery. For the fathers, information was obtained concerning age at delivery and education and/or profession. For the study subjects, information was recorded about the following: gestational age, birth length and weight, placental weight, method of delivery (normal, cesarean section, or with forceps or vacuum extractor), medical problems during hospital stay, presence of jaundice, method of feeding at discharge, and duration of hospital stay after birth. Individuals diagnosed with testicular cancer were identified through the Swedish National Cancer Registry and the Uppsala Regional Cancer Registry. The data were analyzed by use of conditional logistic regression modeling. RESULTS: When testicular cancer was modeled as a single entity, significantly elevated risks were associated with neonatal jaundice (adjusted odds ratio [OR] = 2.30; 95% confidence interval [CI] = 1.07-4.94) and with either low (< 2500 g) or high (> or = 4000 g) birth weight (OR = 2.59; 95% CI = 1.05-6.38 and OR = 1.58; 95% CI = 1.10-2.29, respectively). When seminomas and nonseminomas were analyzed separately, high maternal socioeconomic status (OR = 2.54; 95% CI = 1.05-6.12), neonatal jaundice (OR = 3.96; 95% CI = 1.47-10.69), and low birth weight (OR = 7.62; 95% CI = 1.59-36.60) were associated with nonseminomas, whereas high placental weight (OR = 3.50; 95% CI = 0.97-12.62) suggested increased risk for seminomas. CONCLUSIONS AND IMPLICATIONS: Perinatal exposures appear to influence the risk of testicular cancer, and seminomas and nonseminomas may have somewhat different risk profiles. Future epidemiologic studies should consider the possibility of etiologic heterogeneity in the development of seminomas and nonseminomas.

Birth Weight↗
PubMed1996

Increase in testicular cancer incidence in six European countries: a birth cohort phenomenon.

BACKGROUND: For unknown reasons, the age-standardized incidence of testicular cancer has shown a rapid increase in virtually all countries (mostly Western) studied. For populations with a sufficiently long period of cancer registration, this development can be traced back to the first half of this century. PURPOSE: By evaluating data from six countries with long periods of cancer registration (Denmark, Norway, Sweden, the former German Democratic Republic [East Germany], Finland, and Poland), we sought to determine whether the increase in testicular cancer risk follows a birth cohort pattern and, if so, to quantify and compare any birth cohort effects. METHODS: A total of 30,908 incident cases of testicular cancer, diagnosed from 1945 through 1989 in men who were 20-84 years of age, were identified in population-based cancer registries in the six countries. In addition to performing simple trend analyses, we fitted several Poisson regression models (with the explanatory variables age, time period [calendar time], and birth cohort) to the data. Individual models were estimated by the maximum likelihood method. RESULTS: The age-standardized incidence of testicular cancer was found to vary among the six populations and, on the basis of total registration data, increased annually at rates ranging from 2.3% (in Sweden) to 5.2% (in East Germany). A comparison of several regression models indicated that birth cohort was a stronger determinant of testicular cancer risk than was calendar time for all six populations. Within each population, little variation in testicular cancer risk was observed for men born between 1880 and 1920; thereafter, the risk began to increase. Among men born in Denmark, Norway, and Sweden between 1930 and 1945 (the period encompassing the Second World War), the increasing trend in risk was interrupted (i.e., a leveling in risk occurred). After 1945, an uninterrupted increase in risk was observed for all six populations. With men born around 1905 as the reference group, the relative risk of testicular cancer for those born around 1965 varied from 3.9 (95% confidence interval [CI] = 2.7-5.6) in Sweden to 11.4 (95% CI = 8.3-15.5) in East Germany. CONCLUSIONS AND IMPLICATIONS: The increasing trend in testicular cancer risk observed for these six populations follows a birth cohort pattern. This distinct risk pattern provides a framework for the identification of specific etiologic factors.

Adult↗
PubMed1996

Maternal and perinatal factors associated with non-Hodgkin's lymphoma among children.

This nested case-control study based on 1.7 million live births in Sweden explores the associations between maternal and perinatal factors and the occurrence of childhood non-Hodgkin's lymphoma (NHL). The National Swedish Cancer Registry ascertained 168 cases in successive birth cohorts from 1973 through 1989 recorded in the Swedish Medical Birth Registry. From the nationwide Birth Registry, 5 controls without NHL and alive at the date the case was diagnosed were randomly selected from the pool of children, with each case matched by gender, birth year and birth month. Standardized information on selected maternal and perinatal factors up to one month after delivery were recorded in the Medical Birth Registry. Mothers of children with NHL were more likely than mothers of controls to have undergone Cesarean section [Odds ratio (OR) 1.6] and to have been exposed to paracervical anesthesia during delivery (OR 1.8). Children with NHL were more likely than controls to have endocrine-metabolic disorders (OR 3.3). This study is one of the largest focusing on the etiology of childhood NHL. Most of the maternal and perinatal characteristics studied did not markedly affect risk for childhood NHL, which may be due to maternal and perinatal factors not included in these data or to exposures later in life.

Adolescent↗
PubMed1996

Maternal risk of breast cancer following multiple births: a nationwide study in Sweden.

The association between multiple births and subsequent maternal breast cancer risk was explored in a nested case-control study in Sweden encompassing 19,368 parous women with breast cancer diagnosed up to age 65 years, and 100,459 parous controls. Among cases and controls, there were 329 and 2,031 women, respectively, with a history of at least one live multiple birth. Compared with singleton mothers, breast cancer risk was 12 percent lower (odds ratio = 0.88, 95 percent confidence interval = 0.78-0.99) in women who had had a multiple birth. After stratification for age at diagnosis, evidence of a significant inverse association was found only in women aged 54 years or younger. Birth order of the multiple pregnancy had no apparent risk-modifying effect. Age at earliest multiple birth was unrelated to breast cancer risk. The inverse association between twinning and breast cancer risk may reflect protective physiological features of twin pregnancies. Further research is needed to investigate the role, if any, of increased levels of steroid hormone-binding globulins in mothers of twins and the proposed inhibitory effects of human chorionic gonadotropin and alpha-fetoprotein, both of which are increased during multiple gestations, on breast carcinogenesis. Breast feeding patterns in mothers of twins also may modify their risk of developing breast cancer.

Adult↗
PubMed1996

Parity, age at first and last birth, and risk of breast cancer: a population-based study in Sweden.

Associations between parity and the risk of breast cancer, and the relative importance of age at first and age at last birth on breast cancer risk, were estimated in a case-control study nested in a nation-wide cohort of Swedish women born between 1925 and 1960. A total of 12,782 women with breast cancer and five times as many individually age-matched controls, aged less than 60 years with concomitant fertility information, were included in the analysis. Increasing parity was associated with a pronounced decrease in the risk of breast cancer with each additional birth conferring a 10 percent risk reduction (odds ratio 0.90 [95% CI 0.88-0.91]). In an analysis limited to women with two or more parities, and after adjustment for the effects of ages at interim births, the risk of breast cancer increased by about 13 percent for each five-year increment in age at first birth (odds ratio 1.13 [1.08-1.19]). For every five year-increase in age at last birth there was a small risk increase of marginal statistical significance (odds ratio 1.05 [1.01-1.09]). The present findings contradict recent claims that age at last birth has a stronger effect than age at first birth on breast cancer risk. The dominance of age at first birth as risk modulator is likely to reflect the protection afforded by the terminal differentiation of breast cells induced by a first pregnancy.

Age Factors↗
PubMed1996

Risk of pancreatic and periampullar cancer following cholecystectomy: a population-based cohort study.

An increased risk of pancreatic cancer following cholecystectomy has been reported in some studies but not in others. In order to settle this question, a population-based cohort consisting of 62,615 patients who had undergone cholecystectomy was followed up for the occurrence of pancreatic and periampullar cancer up to 23 years. After excluding the first year after operation, there were 261 pancreatic cancers vs 216.8 expected [standardized incidence ratio (SIR) = 1.20; 95% confidence interval (CI) = 1.06-1.37]; and 11 periampullar cancers vs 7.2 expected (SIR = 1.52; 95% CI = 0.76-2.72). The increased risk of pancreatic cancer was most prominent up to four years after operation, but was also significantly increased 15 years or more after operation (SIR = 1.35; 95% CI = 1.00-1.78). We conclude that there is a modest excess risk of pancreatic and periampullar cancer following cholecystectomy, most prominent up to four years after operation, but that also exists 15 years or more after operation.

Ampulla of Vater↗
PubMed1996

Does age at the last birth affect breast cancer risk?

We studied the relative importance of age at first and age at last full-term pregnancy (FTP) in a large data set of 3950 cases and 11,510 controls, of whom 2263 cases and 7359 controls had two or more FTPs. We found that a 5-year delay in age at first FTP is associated with an odds ratio of 1.17 (95% confidence interval of 1.05-1.29), whereas a 5-year delay in the age of last FTP is associated with an odds ratio of 1.05 (95% confidence interval 0.96-1.14). Misleading results concerning the relative importance of age at first and last FTP may be obtained when parity is only adjusted in broad categories, uniparous women whose FTP is, simultaneously, both the first and the last are not excluded from the analysis, and age at any FTP between the first and last is not controlled for.

Adult↗
PubMed1996

Epidemiology of Kaposi's sarcoma in the Nordic countries before the AIDS epidemic.

Based on data from the Nordic cancer registries, time-related trends in incidence of Kaposi's sarcoma (KS) were analysed in four ethnically similar populations before the AIDS epidemic. Data were available for different time periods in Denmark (1970-79), Sweden (1958-79), Finland (1953-79) and Norway (1953-79). KS was more common among men than among women aged 60 years or more, whereas no differences were observed for younger persons. The incidence of KS differed significantly between the four countries (P = 0.0001); Sweden having the highest and Denmark the lowest rates. Similarly, regional differences in incidence were observed within Sweden, rates being higher in the northern than in the southern areas (Ptrend = 0.002). Overall, in Nordic men the world standardised incidence rose from 0.5/1,000,000 person-years in the period 1953-57 to 1.8/1,000,000 person-years in 1978-79; in Nordic women, the corresponding rates were 0.2/1,000,000 person-years and 0.8/1,000,000 person-years respectively. The rate of increase was similar in Sweden, Finland and Norway (P = 0.14), whereas the short period of observation in Denmark precluded precise assessment of time-related incidence trends. These observations cannot be explained by registrational procedures or known risk factors for KS, and argue that environmental factors play an important role in the development of the disease.

Acquired Immunodeficiency Syndrome↗