Epidemiology of choriocarcinoma in Finland, 1953 to 1999

OBJECTIVE: Choriocarcinoma is a rare tumor with remarkable differences in the incidence in various parts of the world. The available data do not elucidate recent time trends in the incidence of the disease in Western countries. We studied the epidemiology of choriocarcinoma in Finland over a period of 47 years. METHODS: Incidence rates for choriocarcinoma from 1953 to 1999, according to the population-based Finnish Cancer Registry, were calculated per number of deliveries, obtained from the National Research and Development Center for Welfare and Health. Standardized incidence ratios (SIRs) for the years 1971 through 1995 for women born between 1906 and 1945 were calculated by occupation taken from the 1970 Population Census. RESULTS: The incidence of choriocarcinoma was 40/10(6) deliveries for the study period 1953-1999 as a whole. The respective incidence rate calculated per female population and adjusted for age to the world standard population was 1.3/10(6). The incidence, per number of deliveries, was remarkably higher in women above 40 years as compared to younger women. There was a decline in the incidence of the disease in women between 25 and 39 years of age from 53/10(6) deliveries in 1953-1984 to 26/10(6) deliveries in 1985-1999. High occupation-specific risks were observed for nurses (SIR 7.8; 95% confidence interval 2.1-20) and agricultural workers (SIR 11; 95% confidence interval 1.4-40). CONCLUSION: The incidence of choriocarcinoma in Finland is similar to that reported earlier for other Western countries. The recent decline in the incidence of the disease, the enormous increase in the risk among old fertile women, and clustering of cases to certain occupations should be targets of future studies.     

Cancer risk near a polluted river in Finland

The River Kymijoki in southern Finland is heavily polluted with polychlorinated dibenzo-p-dioxins and dibenzofurans and may pose a health threat to local residents, especially farmers. In this study we investigated cancer risk in people living near the river (less than 20.0 km) in 1980. We used a geographic information system, which stores registry data, in 500 m times 500 m grid squares, from the Population Register Centre, Statistics Finland, and Finnish Cancer Registry. From 1981 to 2000, cancer incidence in all people (N = 188884) and in farmers (n = 11132) residing in the study area was at the level expected based on national rates. Relative risks for total cancer and 27 cancer subtypes were calculated by distance of individuals to the river in 1980 (reference: 5.0-19.9 km, 1.0-4.9 km, less than 1.0 km), adjusting for sex, age, time period, socioeconomic status, and distance of individuals to the sea. The respective relative risks for total cancer were 1.00, 1.09 [95% confidence interval (CI), 1.04-1.13], and 1.04 (95% CI, 0.99-1.09) among all residents, and 1.00, 0.99 (95% CI, 0.85-1.15), and 1.13 (95% CI, 0.97-1.32) among farmers. A statistically significant increase was observed for basal cell carcinoma of the skin (not included in total cancers) in all residents less than 5.0 km. Several other common cancers, including cancers of the breast, uterine cervix, gallbladder, and nervous system, showed slightly elevated risk estimates at less than 5.0 km from the river. Despite the limitations of exposure assessment, we cannot exclude the possibility that residence near the river may have contributed to a small increase in cancer risk, especially among farmers.     

Working conditions and health behaviours among employed women and men: the Helsinki Health Study

BACKGROUND: Working conditions influence health, but previous studies on the associations between work-related factors and health behaviours are scarce. The aim of this study was to analyse whether unfavourable working conditions are associated with diet, physical activity, alcohol consumption, and smoking. METHODS: The data derive from postal questionnaires collected in 2000-2001 from 40- to 60-year-old employees of the City of Helsinki (n=6243, response rate: 68%). Logistic regression analysis was used to examine health behaviours as outcomes. Job demands and job control, physically and mentally strenuous work, work fatigue, working overtime and satisfaction with work-home interface were independent variables, adjusted for age, education, occupational social class and marital status. RESULTS: Most of the examined associations between working conditions and health behaviours were not statistically significant. Among women, mentally strenuous work and high job control were associated with a healthy diet. Work fatigue was associated with physical inactivity, whereas physically strenuous work and satisfaction with work-home interface were more often reported by physically active women. Work fatigue was associated with high drinking among men. Low job strain was reported by nonsmoking women, whereas working overtime was associated with nonsmoking among men. CONCLUSIONS: Working conditions were only weakly associated with health behaviours, and the associations varied for different health behaviours.     

Mortality Among Workers Employed in the Titanium Dioxide Production Industry in Europe

OBJECTIVES: To assess the risk of lung cancer mortality related to occupational exposure to titanium dioxide (TiO2). METHODS: A mortality follow-up study of 15,017 workers (14,331 men) employed in 11 factories producing TiO2 in Europe. Exposure to TiO2 dust was reconstructed for each occupational title; exposure estimates were linked with the occupational history. Observed mortality was compared with national rates, and internal comparisons were based on multivariate Cox regression analysis. RESULTS: The cohort contributed 371,067 person-years of observation (3.3% were lost to follow-up and 0.7% emigrated). 2652 cohort members died during the follow-up, yielding standardized mortality ratios (SMRs) of 0.87 (95% confidence interval [CI] 0.83-0.90) among men and 0.58 (95% CI 0.40-0.82) among women. Among men, the SMR of lung cancer was significantly increased (1.23, 95% CI 1.10-1.38); however, mortality from lung cancer did not increase with duration of employment or estimated cumulative exposure to TiO2 dust. Data on smoking were available for over one third of cohort members. In three countries, the prevalence of smokers was higher among cohort members compared to the national populations. CONCLUSIONS: The results of the study do not suggest a carcinogenic effect of TiO2 dust on the human lung.     

Inducible nitric oxide synthase expression in pharyngeal squamous cell carcinoma: relation to p53 expression,clinicopathological data,and survival

OBJECTIVE: To investigate the expression of inducible nitric oxide synthase (iNOS) in oropharyngeal and hypopharyngeal squamous cell carcinoma (SCC) and its relation to p53 expression, histologic differentiation, clinical data, and prognosis. STUDY DESIGN: A retrospective survey. METHODS: Primary tumors for analyses were obtained from 118 patients diagnosed with SCC of the oropharynx or hypopharynx between 1975 and 1998 in eastern Finland. Immunohistochemical analysis was used to evaluate the expression of iNOS and p53. The expression pattern of iNOS was related to p53 expression, clinical data, and survival. RESULTS: High iNOS score was associated significantly with high nuclear p53 expression index (P = .006) and positive cytoplasmic p53 expression (P = .025). The score for iNOS expression was significantly lower in the largest (T4) tumors (P = .043). No association was seen between iNOS score and N or M class, tumor stage, or histologic differentiation. The score for iNOS expression was not related to overall survival. CONCLUSIONS: The expressions of iNOS and p53 seem to be inter-related in pharyngeal SCC, although the causality remains to be clarified. The expression of iNOS shows no prognostic value in pharyngeal SCC.     

Fuzzy detection of EEG alpha without amplitude thresholding

Intelligent automated systems are needed to assist the tedious visual analysis of polygraphic recordings. Most systems need detection of different electroencephalogram (EEG) waveforms. The problem in automated detection of alpha activity is the large inter-individual variability of its amplitude and duration. In this work, a fuzzy reasoning based method for the detection of alpha activity was designed and tested using a total of 32 recordings from seven different subjects. Intelligence of the method was distributed to features extracted and the way they were combined. The ranges of the fuzzy rules were determined based on feature statistics. The advantage of the detector is that no alpha amplitude threshold needs to be selected. The performance of the alpha detector was assessed with receiver operating characteristic (ROC) curves. When the true positive rate was 94.2%, the false positive rate was 9.2%, which indicates good performance in sleep EEG analysis.     

International variation in histologic grading is large,and persistent feedback does not improve reproducibility

Histologic grading systems are used to guide diagnosis, therapy, and audit on an international basis. The reproducibility of grading systems is usually tested within small groups of pathologists who have previously worked or trained together. This may underestimate the international variation of scoring systems. We therefore evaluated the reproducibility of an established system, the Banff classification of renal allograft pathology, throughout Europe. We also sought to improve reproducibility by providing individual feedback after each of 14 small groups of cases. Kappa values for all features studied were lower than any previously published, confirming that international variation is greater than interobserver variation as previously assessed. A prolonged attempt to improve reproducibility, using numeric or graphical feedback, failed to produce any detectable improvement. We then asked participants to grade selected photographs, to eliminate variation induced by pathologists viewing different areas of the slide. This produced improved kappa values only for some features. Improvement was influenced by the nature of the grade definitions. Definitions based on "area affected" by a process were not improved. The results indicate the danger of basing decisions on grading systems that may be applied very differently in different institutions.     

Alternating mitomycin C and BCG instillations versus BCG alone in treatment of carcinoma in situ of the urinary bladder: a nordic study

OBJECTIVES: To evaluate whether, in patients with carcinoma in situ (CIS) of the urinary bladder, alternating instillation therapy with mitomycin C (MMC) and bacillus Calmette-Guerin (BCG) was more effective and less toxic than conventional BCG monotherapy. METHODS: Patients were stratified prospectively for primary, secondary, and concomitant CIS and randomized to one of two regimens. Patients in the alternating group received six weekly intravesical instillations of MMC 40 mg, followed by alternating monthly instillations of BCG 120 mg and MMC for one year. In the monotherapy group, only BCG was instilled on the same schedule. RESULTS: Of 323 enrolled patients, 304 were eligible for analysis. After an overall median follow-up of 56 months, the Kaplan-Meier disease-free estimate for BCG monotherapy was significantly better than that for alternating therapy (p=0.03; log rank test). Risk for progression appeared lower in the BCG monotherapy group (p=0.07), but no differences existed in survival. Besides the regimen, CIS category also predicted outcome to some extent. BCG monotherapy caused significantly more local side-effects and premature cessation of instillation treatment than did the alternating therapy. However, no differences were observed in the number of serious side-effects. CONCLUSION: One-year BCG monotherapy was more effective than the alternating therapy for reducing recurrence and compared well with the best regimens reported from substantially smaller series. The alternating therapy was better tolerated.     

The association between body height and coronary heart disease among Finnish twins and singletons

OBJECTIVE: An inverse association between body height and the incidence of coronary heart disease (CHD) has been observed. However, the mechanisms behind this association are still largely unknown. We will examine the role of genetic and familial factors behind the association in a large twin data set. DESIGN AND SETTING: The data were derived from the Finnish Twin cohort including 2438 singletons, 4073 monozygotic (MZ) twins, and 9202 dizygotic (DZ) twins aged 25-69 years at baseline in 1976. Incident CHD cases were derived from hospital discharge data and cause of death data between 1977 and 1995. Cox regression analysis and conditional logistic regression analysis were used. RESULTS: In population-level analyses no differences in the general risk of CHD between zygosity groups were found. The association between body height and CHD was similar between sexes and zygosity groups. When men and women in all zygosity groups were studied together an increased risk of CHD was found only among the shortest quartile (hazard ratio [HR] = 1.34, 95% CI: 1.14-1.57). Among the twin pairs discordant for CHD a suggestive increased risk for the shorter twin was seen among DZ twins (odds ratio [OR] = 1.19, 95% CI: 0.95-1.48) when men and women were studied together. CONCLUSION: An inverse association between body height and CHD was broadly similar between sexes and twin zygosity groups and was associated with short stature. Among discordant twin pairs we found a weak association among DZ twins but not MZ twins. This may suggest the role of genetic liability behind the association between body height and CHD.