As a part of a larger prospective population study of ischaemic heart disease (IHD) the causes of 5- and 10-year mortality were analysed in 1554 rural inhabitants aged 40 to 59 years (90.0% of the population of this age group) in Northern Finland. The total mortality in 5 years was 2.3% among women and 6.3% among men. The respective 10-year mortality figures were 6.2% and 13.4%. The proportion of IHD as a cause of these deaths among women was 35% and 34% in 5 and 10 years, respectively; among men 46% and 46% of the deaths were due to IHD in 5 and 10 years, respectively. Among women the proportion of strokes was 22% and 19% in 5 and 10 years, respectively; the other causes of death among women amounted to 43% and 47% in 5 and 10 years, respectively. Among men, strokes resulted in the death of 14% and 7% in 5 and 10 years, respectively, the other causes of death amounted to 40% and 47% in 5 and 10 years, respectively. The incidence of IHD as a cause of death among women was higher than previously reported.
To investigate attrition of subjects in a longitudinal study of caries.
A radiographic study of caries and caries-associated factors was carried out in subjects, initially aged 14 years, and followed-up for six years. Attrition of subjects occurred at the last stage of the study.
A nationwide survey of subjects living in fishing, rural farming, and urban communities in Iceland.
A sub-sample of the nationwide random sample comprising 150 subjects was investigated using bitewing radiographs and a structured questionnaire to determine caries-risk factors. Subjects were re-examined at 16 years and 20 years using the same methods.
Mean caries increment from 14-16 years was 3.0 lesions (1.5 lesions/subject/year) but reduced to 2.6 lesions (0.7 lesions/subject/ year) by 20y. The proportion of subjects found to be caries-free at 14 years, 16 years and 20 years, was 29%, 17% and 10%, respectively. "Dropouts" from this study occurred mostly after 16 years. Analysis of subjects dropping out showed that they were least likely to be from the rural farming community but most likely from the fishing community. Those dropping out attended their dentist less frequently, had a higher consumption of carbonated drinks and a higher prevalence and incidence of caries by 16 years.
Subjects with high-risk behaviours, or residents in a fishing community were more likely to drop out of the study. Recognised advantages of conducting longitudinal studies of caries may, therefore, be lost.
The river Iset belongs to the Techa-Iset-Tobol-Irtysh-Ob system contaminated by liquid radioactive wastes from Mayak plutonium facility in 1949-1956. This study represents the first retrospective analysis of postmortem measurements of 90Sr in bones from residents of the Iset riverside settlements in 1960-1982. It was shown that 90Sr concentration in bones of residents lived in settlements located downstream from the Techa river mouth (Shadrinsk, Isetskoye, Yalutorovsk) was 5 times higher than average 90Sr concentration in bones of the Russian residents. There was not statistically significant difference in accumulated 90Sr in bones between residents of the considered Iset' settlements indicating similar levels of 90Sr ingestion. Dietary 90Sr intake was reconstructed from the measurements of the radionuclide in bones. Total 90Sr dietary intake in 1950-1975 was 68 kBq; and 90% of the intake occurred in 1950-1961. In 1960s, 90Sr-contamination of the diet in settlements located downstream from the Techa river mouth was mostly (by 70%) due to global fallouts. Absorbed dose in the red bone marrow cumulated over 25 years of exposure was equal to 14 (4.7-42) mGy.