Breast cancer risk in monozygotic and dizygotic female twins: a 20-year population-based cohort study in Finland from 1976 to 1995.
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This population-based study investigated the occurrence of breast cancer over a 20-year period in a cohort of monozygotic (MZ) and dizygotic (DZ) twins in Finland. Altogether, 13,176 female twins of known zygosity who were living in Finland at the end of 1975 were identified from the Finnish Twin Cohort Study and followed-up for cancer through the Finnish Cancer Registry for the years 1976-1995. Standardized incidence ratios (SIRs) were calculated, based on national cancer incidence rates. The relative risk of breast cancer for MZ twins compared to DZ twins was decreased [SIR(MZ)/SIR(DZ) ratio = 0.78; 95% confidence interval (CI), 0.58-1.0]; the decreased risk for MZ twins (SIR = 0.76; 95% CI, 0.58-1.0) accounted for this result, whereas the risk for DZ twins did not differ from the general population risk (SIR = 0.98; 95% CI, 0.84-1.1). There was no risk decrease among MZ twins in other cancers related to reproductive behavior; i.e., number of children and age at first birth seem not to explain the decreased risk of breast cancer. Our results, which are in line with earlier studies on the same topic, suggest that prenatal influences or postnatal behavioral factors may protect MZ female twins from breast cancer. (+info)
International trends in rates of hypospadias and cryptorchidism.
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Researchers from seven European nations and the United States have published reports of increasing rates of hypospadias during the 1960s, 1970s, and 1980s. Reports of increasing rates of cryptorchidism have come primarily from England. In recent years, these reports have become one focus of the debate over endocrine disruption. This study examines more recent data from a larger number of countries participating in the International Clearinghouse for Birth Defects Monitoring Systems (ICBDMS) to address the questions of whether such increases are worldwide and continuing and whether there are geographic patterns to any observed increases. The ICBDMS headquarters and individual systems provided the data. Systems were categorized into five groups based on gross domestic product in 1984. Hypospadias increases were most marked in two American systems and in Scandinavia and Japan. The increases leveled off in many systems after 1985. Increases were not seen in less affluent nations. Cryptorchidism rates were available for 10 systems. Clear increases in this anomaly were seen in two U.S. systems and in the South American system, but not elsewhere. Since 1985, rates declined in most systems. Numerous artifacts may contribute to or cause upward trends in hypospadias. Possible "real" causes include demographic changes and endocrine disruption, among others. (+info)
Lipoprotein(a) levels and apolipoprotein(a) isoforms related to life style risk factors.
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Lipoprotein(a) [Lp(a)] has been considered to be a predictor of premature coronary heart disease and other cardiovascular diseases. Lp(a) levels are largely genetically determined, but the detailed mechanism of Lp(a) elevation is uncertain. We examined the association between Lp(a) levels and apolipoprotein(a) [apo(a)] phenotypes as well as that of Lp(a) level and other various conditions. The subjects were 280 healthy Japanese (102 males and 178 females) aged 39 to 70 years who were living in a rural community in 1992. We obtained apo(a) phenotypes determined by SDS-PAGE as well as Lp(a) levels and other cardiovascular risk factors. We combined apo(a) phenotypes form 4 groups according to molecular weights (from high apo(a) molecular weight to low: I, II, III and IV). Lp(a) levels were associated with apo(a) phenotype-groups, that is, they were inversely associated with apo(a) molecular weight. Small apo(a) phenotypes were less frequent than large ones. The median Lp(a) level was higher in smoking (29.2 mg/dL) than in non-smoking subjects (18.5 mg/dL) in phenotype-group III. Adjusted means of total cholesterol and fibrinogen levels in apo(a) phenotype-group IV were the highest of all phenotype-groups. Age, apo(a) phenotype, smoking status, total cholesterol and fibrinogen were positively correlated with Lp(a) levels by multiple regression analysis. Lp(a) levels were found to be mainly associated with apo(a) phenotype, but varied broadly within the same apo(a) phenotype at various conditions, such as smoking status and high total cholesterol. (+info)
Swimming-associated outbreak of Escherichia coli O157:H7.
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In 1997 the first outbreak of Escherichia coli O157:H7 infections involving 14 cases occurred in Finland. A case was defined as a resident of Alavus with an episode of diarrhoea between 5 and 17 July 1997, and from whom E. coli O157:H7 was isolated from stool. The investigation included case searching and a population-based case control study. Five primary and eight symptomatic secondary cases of E. coli O157:H7 illness were detected. In the 10 days before the outbreak, all 5 primary patients (aged 3-8 years), but only 6 of 32 population controls from the same age range (Fisher's test, P < 0.001) and 4 of 10 sibling controls (P < 0.05) had visited (but had not necessarily bathed in) a shallow beach popular among young children. Four out of 5 primary cases had remained within 5 m of the beach while swimming and had swallowed lake water compared to 1 of 5 population controls. These analytical epidemiologic findings incriminated fresh lake water as the vehicle of E. coli O157:H7 transmission. (+info)
The risk of Guillain-Barre syndrome following infection with Campylobacter jejuni.
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To estimate the incidence of Guillain-Barre syndrome (GBS) following Campylobacter jejuni infection (CI) we studied three populations where outbreaks of CI had occurred involving an estimated 8000 cases. No case of GBS was detected in the 6 months following the outbreaks in the local populations. The point estimate for the risk of GBS following CI estimated in this study was 0 in 8000 (95% confidence interval 0-3). (+info)
Is group C meningococcal disease increasing in Europe? A report of surveillance of meningococcal infection in Europe 1993-6. European Meningitis Surveillance Group.
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A surveillance system to assess the impact and changing epidemiology of invasive meningococcal disease in Europe was set up in 1987. Since about 1991, contributors from national reference laboratories, national communicable disease surveillance centres and institutes of public health in 35 European countries provided information on all reported cases of meningococcal disease in their country. We describe some trends observed over the period 1993-6. The main findings were: the overall incidence of meningococcal disease was 1.1 per 100000 population but there was some evidence of a slow increase over time and with northern European countries tending to have a higher incidence (Kendall correlation 0.5772, P < 0.001), an increasing predominance of serogroup C, and a shift in the age distribution towards teenagers and away from younger children (chi2 test for trend 44.56, P < 0.0001), although about half of the cases were under 5 years of age. The overall case fatality rate was 8.3% and the most common serosubtypes were B:15:P1.7,16 and C:2a:P1.2,5. (+info)
Clinical and epidemiological features of group A streptococcal bacteraemia in a region with hyperendemic superficial streptococcal infection.
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Reports of increasing incidence and severity of invasive group A streptococcal (GAS) infections come mainly from affluent populations where exposure to GAS is relatively infrequent. We conducted a 6-year retrospective review of GAS bacteraemia in the Northern Territory of Australia, comparing the Aboriginal population (24% of the study population), who have high rates of other streptococcal infections and sequelae, to the non-Aboriginal population. Of 72 episodes, 44 (61%) were in Aboriginal patients. All 12 cases in children were Aboriginal. Risk factors were implicated in 82% of episodes (91% in adults) and there was no significant difference in the proportion of Aboriginal compared to non-Aboriginal patients with at least one risk factor. Genetic typing of isolates revealed no dominant strains and no evidence of a clone which has been a common cause of these infections elsewhere. (+info)
Epidemiology of Streptococcus pneumoniae infection in Malaysia.
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During a 1-year period from October 1995 to September 1996, 273 isolations of Streptococcus pneumoniae were made from various types of clinical specimens. The majority of the isolates (39.2%) were from sputum whilst 27.5% were from blood, CSF and other body fluids. The organism was isolated from patients of all age groups, 31.1% from children aged 10 years and below, 64.7% of which come from children aged 2 years or below. The majority of the isolates belong to serotypes 1, 6B, 19B, 19F and 23F. Serotypes 1 and 19B were the most common serotypes associated with invasive infection. About 71.9% of the invasive infections were due to serotypes included in the available 23 valent polysaccharide vaccine. The rates of resistance to penicillin and erythromycin were 7.0 and 1.1% respectively. Our findings show that the serotypes of S. pneumoniae causing most invasive infections in Malaysia are similar to those in other parts of the world and the available vaccine may have a useful role in this population. (+info)