Prostate cancer in Denmark: a 50-year population-based study

OBJECTIVES: To review the trends in prostate cancer (PC) incidence and mortality rates in Denmark during a 50-year period. METHODS: A population-based register study was performed of all new cases of PC recorded in the Danish Cancer Registry from 1943 to 1992. RESULTS: The age-standardized incidence rate for PC increased from 11.5/100,000 in 1943 to 1947 to 30.9/100,000 in 1988 to 1992. Age-specific incidence rates increased in all age groups over 50 years of age. Mortality rates increased from 13.5/100,000 in 1953 to 1957 to 17.8/100,000 in 1988 to 1992. No major changes in the distribution of age, stage at the time of diagnosis, or in diagnostic procedures were found, indicating that the observed change in incidence rates was not caused by attempted early detection or changes in diagnostic strategy. CONCLUSIONS: Our data suggest that the increased PC incidence observed during the period of cancer registration in Denmark represents a true increase in the number of patients with clinical PC.     

Cutaneous malignant melanoma in Scotland: incidence, survival, and mortality, 1979-94. The Scottish Melanoma Group

OBJECTIVE: To determine the changing incidence of and mortality from cutaneous malignant melanoma in Scotland from 1979 to 1994. DESIGN: Detailed registration of clinical and pathological features, surgical and other treatment, and follow up of all cases of cutaneous malignant melanoma diagnosed from 1979 to 1994 and registered with specialist database for Scotland. SETTING: Scotland. SUBJECTS: 6288 patients with invasive primary cutaneous malignant melanoma diagnosed between 1 January 1979 and 31 December 1994. RESULTS: The annual age standardised incidence of cutaneous malignant melanoma rose significantly from 3.5 to 7.8 per 100,000 per year in men and from 6.8 to 12.3 per 100,000 per year in women (P < 0.001 for both). World standardised rates increased from 2.7 to 6.0 per 100,000 per year in men and 4.6 to 8.50 per 100,000 in women. The incidence of melanoma continued to increase significantly in men of all ages during the study, but the rate stabilised in women after 1986. Mortality from cutaneous malignant melanoma was 1.3 per million per annum in men in 1979, rising to 2.3 per million per annum in 1994 (P < 0.01); it was 2.4 per million per annum in women in 1979, falling to 1.9 per million per annum in 1994 (P = 0.09). The underlying mortality trends showed a continuing rise for men but a downward trend for women that was not significant (P = 0.09). In men, melanoma free survival was 69% at 5 years and 61% at 10 years; in women the corresponding rates were 82% and 75%. Younger patients had higher survival rates, which were not entirely explained by thinner tumours. Over the 15 year period, survival rates improved by 12% overall, only partly owing to thinner tumours. CONCLUSIONS: In Scotland the incidence of melanoma in women has stabilised, while mortality associated with melanoma in women shows a downward trend.     

Trends in incidence and mortality rates for prostate cancer before and after prostate-specific antigen introduction. A registry-based study in southeastern Netherlands, 1971-1995

The incidence of prostate cancer has increased considerably over the past two decades, partly due to the increased detection of subclinical cases. In southeastern Netherlands, a region of almost 1 million inhabitants with good access to specialised medical care, prostate-specific antigen (PSA) assays were not introduced until 1990, allowing us to investigate the nature of the increases in incidence. Age-adjusted (European Standardised Rate) and age-specific rates were calculated using incidence data from the population-based Eindhoven Cancer Registry and mortality data from Statistics Netherlands. The age-adjusted incidence, which increased from 36 per 100,000 in 1971 to 55 per 100,000 in 1989, included all grades as well as metastasised prostate cancer. The age-adjusted mortality mainly fluctuated in this period, but increased among men aged 55-64 years from 12 per 100,000 in 1980 to 25 per 100,000 in 1989. After 1990, the age-adjusted incidence further increased to 80 per 100,000 in 1995, the increase representing mainly low-grade localised prostate cancer, presumably due to increasing opportunistic PSA testing, especially after 1993. A real increase in incidence may have occurred before 1993. However, pending results of randomised trials, judicious application of PSA testing seems justifiable to avoid unnecessary intervention without reducing mortality.     

Inflammatory breast carcinoma incidence and survival: the surveillance, epidemiology, and end results program of the National Cancer Institute, 1975-1992

BACKGROUND: Little is known about the cause of inflammatory breast carcinoma (IBC), the most aggressive form of breast cancer. To the authors' knowledge, no studies have investigated whether IBC risk factors are different from those for breast carcinoma overall, and there has been only one report of IBC incidence and survival patterns. METHODS: The authors used data from the Surveillance, Epidemiology, and End Results program of the National Cancer Institute for the period 1975-1992 to calculate age-adjusted incidence and survival rates for 913 white and 121 African American women with IBC involving dermal invasion of lymphatic ducts and 166,375 white and 13,674 African American women with other types of breast carcinoma (non-IBC). RESULTS: Between 1975-1977 and 1990-1992, IBC incidence doubled, increasing among whites from 0.3 to 0.7 cases per 100,000 person-years and among African Americans from 0.6 to 1.1 cases. However, rates for African Americans varied due to the small numbers of IBC cases. The twofold increase in IBC incidence was higher than that observed for non-IBC during the same period (27% for African Americans and 25% for whites). IBC patients were significantly younger at diagnosis than non-IBC patients; and among both IBC and non-IBC patients, African Americans were younger than whites. Overall survival was significantly worse for IBC patients than for non-IBC patients and for African Americans than for whites. Among whites, 3-year survival improved more for IBC patients than for non-IBC patients between 1975-1979 and 1988-1992, increasing from 32% to 42% for IBC patients (P=0.0001) and from 80% to 85% for non-IBC patients (P=0.0001). CONCLUSIONS: The disparities observed in incidence trends and age at diagnosis, particularly according to race, highlight the need for further investigation of the differences between IBC and non-IBC incidence.     

Incidence of insulin-dependent diabetes mellitus in young adults: experience of 1,587,630 US Navy enlisted personnel

First hospitalizations (n = 1,293) for diabetes mellitus between 1974 and 1988 were used as a surrogate for insulin-dependent diabetes mellitus incidence among 17-34-year-old US Navy enlisted personnel followed for 6,077,856 person-years. In the 15-year period, the overall incidence of insulin-dependent diabetes mellitus was 21.3 per 100,000 person-years. Incidence did not differ significantly by sex, but was higher for blacks than whites (28.4 vs. 20.2 per 100,000 person-years, respectively; p < 0.05). Incidence increased with age threefold for white men and fivefold for black men (p < 0.05) between the ages of 17-19 and 30-34 years.     

Famine, fiber, fatty acids, and failed colonic absorption: does fiber fermentation ameliorate diarrhea?

The annual incidence of malignant neoplasms of the ovary has increased in the Czech Republic between 1961 and 1988 from 14.3 to 17.2 newly notified cases per 100,000 women. The highest incidence, 47.03, is in the age group from 70 to 74 years. It participates in the overall mortality from malignant tumours of the genitalia by 41.6%, although in the total incidence it accounts for 25%. The lethality calculated from the incidence and mortality in the Czech Republic in similar as in other countries--79%. This is consistent with the generally reported survival period after treatment which is 20-30%. Hospital statistics report more favourable results. Introduction of new therapeutic methods so far did not lead to marked improvement of therapeutic results. The latter are influenced more by detection of the disease in early stages.     

Prostate cancer in American Indians, New Mexico, 1969 to 1994

PURPOSE: Prostate cancer is the most frequently diagnosed cancer as well as the leading cause of cancer death among American Indian men. MATERIALS AND METHODS: To describe further the occurrence of prostate cancer among American Indian men, we examined population based incidence, treatment, survival and mortality data for American Indians in New Mexico during the 25-year period 1969 to 1994. RESULTS: Although American Indian men have a lower risk of prostate cancer than nonHispanic white men, the incidence and mortality rates are rising for American Indians, and mortality rates are now equal to those for nonHispanic white men. During the 25-year period age adjusted incidence rates for American Indians increased from 42.2/100,000 (95% confidence interval 27.1 to 57.3) to 64.6/100,000 (95% confidence interval 46.2 to 83.0). The burden of prostate cancer among American Indian men compared with nonHispanic white men was reflected in disproportionately high mortality rates in relation to incidence rates. The mortality rates were high because American Indian cases were more advanced at diagnosis, 23.3% of prostate cancers were diagnosed after distant spread had occurred compared with 11.6% for nonHispanic white men and the 5-year relative survival rate was poorer (57.1% compared with 77.6% for nonHispanic white men). CONCLUSIONS: Effective and culturally sensitive cancer control efforts for prostate cancer in American Indian communities are urgently needed.     

Malignant mesothelioma: incidence, survival and relative risks in selected municipalities 1943-1992

The development in incidence rates and survival in Denmark, and the rate-ratio in selected municipalities that had industries utilizing asbestos was studied in 1865 cases of malignant mesothelioma identified in the Danish Cancer Registry 1943-1992. For men a steady increase in the incidence to 1.6 per 100,000 personyears in 1992 was found, while the rate for women decreased to 0.28 per 100,000 personyears. Age-specific incidence rates were highest for the older age-groups. An unexplained difference in the distribution of pleural and peritoneal cancers was seen between men and women. The average survival was 6.9 months for men and 7.8 for women and had not changed during the period of observation. The average rate-ratio for the selected municipalities was 1.97 (95% confidence intervals: 1.73-2.24) for men and 1.35 (1.08-1.69) for women. Improvements in working conditions in terms of minimizing asbestos exposure were introduced in 1980. Considering the latency period from exposure to diagnosis of 25-30 years, the impact of this measure on the rate of incidence cannot be expected before the year 2000.     

Puberty, IDDM, and death in Japan. Diabetes Epidemiology Research International Study Group

OBJECTIVE: To investigate the impact of age at onset on the prognosis of childhood IDDM in Japan. RESEARCH DESIGN AND METHODS: The study population consisted of 987 prepubertal-onset and 345 pubertal-onset IDDM cases who were registered by two nationwide surveys and who were diagnosed between 1965 and 1979. The living status was identified as of 1 January 1990 with the ascertainment rate of 96.5%. Prognosis was evaluated by cause- and age-specific mortality rates and life-table analyses; in addition, an attained-age-matched case-control study was analyzed by conditional logistic regression. RESULTS: The adjusted mortality rates per 100,000 person-years for the pubertal-onset cases were significantly higher than those of the prepubertal-onset cases (835 [95% CI 573-1,168] vs. 391 [283-526]). Life-table analyses revealed that the survival rate of the pubertal-onset cases was lower than that of the prepubertal-onset cases for each observation period. Life-table analyses after the age of 15 years indicated that the prognosis of pubertal cases was almost the same as that of the prepubertal cases despite having a shorter duration of diabetes. The attained-age-matched case-control study indicated that the pubertal onset was a potent determinant of death. CONCLUSIONS: The prognosis of pubertal-onset IDDM was considerably poorer than that of prepubertal-onset IDDM.     

Breast cancer--incidence, mortality and stage shifting in Norway

The age-standardized incidence rate of breast cancer has increased by 50% over the period 1965-94. There has been a much lesser increase in the corresponding age-standardized mortality rate because of better treatment and stage shifting. Stage shifting means that the proportion of individuals with a given clinical stage changes over time. The proportion of individuals diagnosed as clinical stage 1 was seen to increase from about 50% to 60% in the time period mentioned above. The proportion classified as stage 2 at the time of diagnosis is constant at 30%. The relative numbers of individuals diagnosed as stage 3 or 4 were reduced from 10% to 3% and from 10% to 5%, respectively. After correction for confounding effect of age and the clinical stage, the age-standardized 3-year relative survival rate increased from 90% to 95% and from 67% to 85% for stages 1 and 2, respectively. The impact of advancing breast cancer diagnosis independent of the screening programme, is discussed. Finally, the evaluation of screening programmes using shift migration models and simulations is discussed.     

Spectrum of 2,836 cases of invasive bacterial or fungal infections in children: results of prospective nationwide five-year surveillance in Finland. Finnish Pediatric Invasive Infection Study Group

In a prospective nationwide laboratory-based surveillance study of all invasive bacterial and fungal infections among children < 16 years of age, 2,836 clinical cases were registered during the 5-year period 1985-1989. Of these cases, 136 were polymicrobial. During the study period, nationwide administration of Haemophilus influenzae type b conjugate vaccine reduced the incidence rates of invasive infection caused by this organism. The most common clinical diagnosis (48% of cases) was bacteremia without an identified focus of infection. The age-specific annual incidence rates of all invasive infections in children < or = 15 years of age, in children < or = 4 years of age, in children < or = 1 year of age, and in children < or = 28 days of age were 55.8, 141.4, 272.7, and 2,749.0 cases/100,000 person-years, respectively. Thirty percent of the children in the study had an underlying condition predisposing to infection. The case-fatality rate was 4.1% for all cases of invasive infection.     

Pertussis in Massachusetts, 1981-1991: incidence, serologic diagnosis, and vaccine effectiveness

Massachusetts provides diphtheria-tetanus toxoid-pertussis (DTP) vaccine, and since 1980 has monitored pertussis with a statewide diagnostic service. The incidence of bacteriologically confirmed pertussis was 104.5 per 100,000 person-years in 1-month-old infants and declined progressively thereafter. Infants < 6 months old experienced disproportionate morbidity: 44% of bacteriologically confirmed pertussis, 64% of hospitalizations, and 71% of hospital days. Most children with pertussis had received < 3 DTP doses during childhood, whereas 87% of adolescents with pertussis had received > or = 4 doses. Serodiagnosis by single serum anti-pertussis toxin antibody ELISA increased the incidence of confirmed pertussis in persons 11-19 years old from 3.0 to 12.9 per 100,000 and in persons > or = 20 years old from 0.16 to 0.56 per 100,000. Bacteriologic methods underestimate pertussis incidence, but a single serum anti-pertussis toxin antibody ELISA is a practical method for population-based diagnosis in adolescents and adults.     

The contribution of non-insulin-dependent diabetes to lower-extremity amputation in the community

BACKGROUND: Despite the significant public health burden of lower-extremity amputations in diabetes mellitus, few data are available on the epidemiology of lower-extremity amputations in diabetes mellitus in the community setting. METHODS: A retrospective incidence cohort study based in Rochester, Minn, was conducted. RESULTS: Among the 2015 diabetic individuals free of lower-extremity amputation at the diagnosis of diabetes mellitus, 57 individuals underwent 79 lower-extremity amputations (incidence, 375 per 100,000 person-years; 95% confidence interval, 297 to 467). Among the 1826 patients with non-insulin-dependent diabetes mellitus, 52 underwent 73 lower-extremity amputations, and the subsequent incidence of lower-extremity amputation among these residents was 388 per 100,000 person-years (95% confidence interval, 304 to 487). Of the 137 insulin-dependent diabetic patients, four subsequently underwent five lower-extremity amputations (incidence, 283 per 100,000 person-years; 95% confidence interval, 92 to 659). Twenty-five years after the diagnosis of diabetes mellitus, the cumulative risk of one lower-extremity amputation was 11.2% in insulin-dependent diabetes mellitus and 11.0% in non-insulin-dependent diabetes mellitus. When compared with lower-extremity amputation rates for Rochester residents without diabetes, patients with non-insulin-dependent diabetes mellitus were nearly 400 times more likely to undergo an initial transphalangeal amputation (rate ratio, 378.8) and had almost a 12-fold increased risk of a below-knee amputation (rate ratio, 11.8). In this community, more than 60% of lower-extremity amputations were attributable to non-insulin-dependent diabetes mellitus. CONCLUSIONS: These population-based data document the magnitude of the elevated risk of lower-extremity amputation among diabetic individuals. Efforts should be made to identify more precisely risk factors for amputation in diabetes and to intervene in the processes leading to amputation.     

The role of hormone replacement therapy in the risk for breast cancer and total mortality in women with a family history of breast cancer

BACKGROUND: The risks and benefits of hormone replacement therapy (HRT) are of considerable interest and importance, especially in terms of whether they differ among subsets of women. OBJECTIVE: To determine whether HRT is associated with increased risks for breast cancer and total mortality in women with a family history of breast cancer. DESIGN: Prospective cohort study. SETTING: Population-based sample of midwestern post-menopausal women enrolled in an observational study of risk factors for cancer. PARTICIPANTS: Random sample of 41,837 female Iowa residents 55 to 69 years of age. MEASUREMENTS: Incidence rates of and relative risks for breast cancer (n = 1085) and total mortality (n = 2035) through 8 years of follow-up were calculated by using data from the State Health Registry of Iowa and the National Death Index. RESULTS: A family history of breast cancer was reported by 12.2% of the cohort at risk. Among women with a family history of breast cancer, those who currently used HRT and had done so for at least 5 years developed breast cancer at an age-adjusted annual rate of 61 cases per 10,000 person-years (95% CI, 28 to 94 cases); this rate was not statistically significantly higher than the rate in women who had never used HRT (46 cases per 10,000 person-years [CI, 36 to 55 cases]). Among women with a family history, those who used HRT had a significantly lower risk for total mortality than did women who had never used HRT (relative risk, 0.67 [CI, 0.51 to 0.89]), including total cancer-related mortality (relative risk, 0.75 [CI, 0.50 to 1.12]). The age-adjusted annual mortality rate for women using HRT for at least 5 years was 46 deaths per 10,000 person-years (CI, 19 to 74 deaths); this is roughly half the rate seen in women who had never used HRT (80 deaths per 10,000 person-years [CI, 69 to 92 deaths]). CONCLUSIONS: These data suggest that HRT use in women with a family history of breast cancer is not associated with a significantly increased incidence of breast cancer but is associated with a significantly reduced total mortality rate.     

Endogenous adenosine attenuates long-term depression and depotentiation in the CA1 region of the rat hippocampus

We describe a series of 144 cases of leptospirosis diagnosed in 1989 in New Caledonia. The incidence rate was 90 per 100,000 person-years, with a specific mortality rate of 4% patients. Those affected (100 males, 44 females) were mainly aged 20 to 40 years. Incidence in rural areas (112 per 100,000 person-years) was seven times higher than in urban settlements. Two periods with higher incidence were noticed corresponding to highest rainfall. Twenty-nine of the cases occurred in individuals with professions commonly associated with leptospirosis. Contacts with rats, dogs and ditch or river water were the most frequently mentioned. The clinical expression of the disease was polymorphic: 60% of the patients had mild symptoms, 40% were acute forms including Weil's disease. Of 57 hospitalized, 23% were admitted with an initial diagnosis of dengue, and 37% with leptospirosis. Main clinical syndromes were: icterus and/or renal syndrome in 50% of patients, cardiac syndrome in 65%, acute myalgies in 58% and pulmonary syndrome in 50%. Although hemorrhages were uncommon (17%), 40% of the cases demonstrated thrombocytopenia (< 50,000/m3). Pancreatic involvement with hyperamylasemia was evidenced in 50% of cases. Twelve serogroups of Leptospira were implicated, Icterohaemorragiae predominated (41%), but was not associated with severe forms. In New Caledonia, like in all tropics, leptospirosis must be considered as an environmental diseases, professional activities being just an additional risk factor. Use of serology as a reliable tool for confirmation of cases in areas of high environmental contamination is discussed.     

Does colonoscopic polypectomy reduce the incidence of colorectal carcinoma?

The study's objective was to examine whether there is evidence that colonoscopic polypectomy reduces the incidence of colorectal cancer. The records of all patients who underwent colonoscopic polypectomy by a single surgeon between 1974 and 1991 were reviewed. Patients with colorectal cancer diagnosed at the initial colonoscopy, with a history of colorectal cancer, inflammatory bowel disease or familial adenomatous polyposis or with only hyperplastic polyps were excluded. There were 1008 remaining patients, of whom 645 have attended at least one follow-up colonoscopic examination, and these 645 patients from the basis of the study, because the incidence of cancer is known exactly in this group. The mean period of follow up was 4.4 years and the mean number of follow-up colonoscopic examinations was 2.2. There was a total of 2847 person-years of colonoscopic follow up. The expected incidence of cancer, age and sex adjusted, is calculated using Australian epidemiological figures. The observed incidence of cancer was 3 cases (all asymptomatic) per 2847 person-years, which is indistinguishable from the general population's risk of 3.75 cases per 2847 person-years. Analysis of previous publications suggests that patients with adenomas are at an increased risk of developing colorectal cancer of about 2.5 times the general population's risk. If correct, then the observed incidence of 3 cases per 2847 person-years is less than the expected incidence of 9.4 cases per 2847 person-years. This analysis suggests colonoscopic polypectomy does reduce the incidence of colorectal cancer.     

Serial measurement of Epstein-Barr viral load in peripheral blood in pediatric liver transplant recipients during treatment for posttransplant lymphoproliferative disease

BACKGROUND: The aim of this follow-up study was to assess whether there has been any increase in the percentage of patients offered attempted curative surgery for pancreatic carcinoma and whether the overall survival rate has improved, during the time period 1977-1991. METHODS: Details of new cases of pancreatic carcinoma arising in the population of Malm? during the study period were retrieved from the Local Tumour Register in Lund, Sweden. In all, 740 patients were found; 575 of these were diagnosed before death. Kaplan-Meier analysis was used to calculate overall survival rates, and Cox regression analysis was used to assess survival in relation to year of diagnosis after adjustment for sex, age at diagnosis and stage of disease. RESULTS: Cytological or histopathological evidence of the disease was given in 95 per cent of cases. The overall 5-year survival rate was 0.5 per cent (three of 575). Curative surgery was attempted in 24 patients (4.2 per cent); the proportion undergoing curative surgery increased in the last part of the study. Two of the 24 patients in this group survived for 5 years. CONCLUSION: The prognosis in pancreatic carcinoma remains dismal. Attempted curative surgery still is the only hope for cure, but the group of patients that can be offered this possibility is very limited. In this study, an increase was found in the proportion of patients who were offered attempted curative surgery, but there was no statistically significant increase in the 5-year survival rate following surgery.     

Paracoccidioidomycosis: an epidemic in the Republic of Paraguay, the center of South America

The investigation done on the frequency or incidence of Paracoccidioidomycosis in the Republic of Paraguay, with the cases appeared and registered in the Institute of Pathology of Asuncion, presents an incidence rate of 0.46 per 100,000 in the total population; 0.52 per 100,000 in the population at risk. Considering the exposed masculine population the rate is 1.03 per 100,000 and for the feminine 0.02 per 100,000. The age group most affected is within the 50-54 year range with 3.54 per 100,000, the highest rate of all the groups studied. These are the incidence in a strongly exposed population which is controlled and well known. The period of 10 years (1960/69) which has been chosen for this investigation, shows a frequency of the mixed type (lymphatic-visceral or lymphoma-type) which reaches 25% of the total, and a low frequency for the pulmonary form which reaches a mere 12.5%. The mucocutaneous lesion with the involvement of the regional lymph nodes is the dominating form. Considering three consecutive 5 year periods between 1960 to 1974, no cases with proved pulmonary involvement were found until 1964; from 1965 to 1969 the percentage of pulmonary lesions in all the cases considered was 23.0% and from 1970 to 1974 reached to 38.4%. However, mucocutaneous and the lymphatic-visceral or mixed forms do not show significant variations. The rats are small and represent the incidence of this mycosis. It is suggested that a failure of the immunologic system would be found in those affected by the disease and there would be a strong resistence in the majority of the population exposed or within the endemic area of the infection.     

Two cases of delayed posttraumatic vasospasm followed by brain SPECT

OBJECTIVES: To describe the incidence of Guillain-Barré syndrome in Sweden during the period 1978-93 and its temporal and geographical variations. METHODS: Stratified and Poisson regression analyses and tests for detection of small epidemics were applied to population based hospital discharge data from 2257 incident cases of Guillain-Barré syndrome in Sweden during the study period. RESULTS: The incidence of Guillain-Barré syndrome was (1) 1.77 per 100000 person-years when age adjusted to the European population; (2) higher in males; and (3) stable across time, although occasional increases of annual incidence rates were found-namely, in 1978 (relative risk (RR) 1.30 (95% CI 1.10-1.54)), and in 1983 (RR 1.24 (95% CI 1.06-1.40)). The incidence increased with age and was bimodal, with peaks at 20-24 and 70-74 years. There was a moderate but significant seasonality with a peak in August, particularly among the young age groups. The age adjusted incidence by county varied from 1.11 to 2.57 per 100000 person-years. Neither temporal nor spatial clustering was significant, except during the period July-September in 1983 at ages below 40 years. CONCLUSIONS: The incidence of Guillain-Barré syndrome in Sweden during the period 1978-93 had a magnitude similar to those described in other surveys, a bimodal distribution by age, and modest geographical and temporal variations with significantly high rates in 1978 and 1983 and in autumn. Minor outbreaks might have passed unnoticed up to the present. Whereas reported drug induced cases of Guillain-Barré syndrome may in part explain the high incidence in 1983, the cause of the aberrant incidence in 1978 remains unknown. Epidemiological surveillance of Guillain-Barré syndrome in Sweden might have been useful.