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Electromagnetic fields have been suggested to contribute to the risk of depression by causing pineal dysfunction. Some epidemiologic studies have supported this possibility but have generally reported crude methods of exposure assessment and nonsystematic evaluation of depression. Using two available nationwide data sets, the authors identified from the Finnish Twin Cohort Study 12,063 persons who had answered the 21-item Beck Depression Inventory of self-rated depressive symptoms in 1990. The personal 20-year histories of exposure (i.e., distance and calculated annual average magnetic fields) before 1990 to overhead 110- to 400-kv power lines were obtained from the Finnish Transmission Line Cohort Study. The adjusted mean Beck Depression Inventory scores did not differ by exposure, providing some assurance that proximity to high-voltage transmission lines is not associated with changes within the common range of depressive symptoms. However, the risk of severe depression was increased 4.7-fold (95% confidence interval 1.70-13.3) among subjects living within 100 m of a high-voltage power line. This finding was based on small numbers. The authors recommend that attempts be made to strive for a better understanding of the exposure characteristics in relation to the onset and course of depression.

We studied the cumulative incidence, concordance rate and heritability for diabetes mellitus in a nationwide cohort of 13,888 Finnish twin pairs of the same sex. The twins were born before 1958 and both co-twins were alive in 1967. Data on diabetes were derived through computerized record linkage from death certificates, the National Hospital Discharge Register and the National Drug Register. Records were reviewed in order to assign a diagnostic category to the 738 diabetic patients identified. Of these patients 109 had Type 1 (insulin-dependent) diabetes, 505 Type 2 (non-insulin-dependent) diabetes, 46 gestational diabetes, 24 secondary diabetes, 38 impaired glucose tolerance and 16 remained unclassified. The cumulative incidence of diabetes was 1.4 % in men and 1.3 % in women aged 28–59 years and 9.3 % and 7.0 % in men and women aged 60 years and over, respectively. The cumulative incidence did not differ between monozygotic and dizygotic twins. The concordance rate for Type 1 diabetes was higher among monozygotic (23 % probandwise and 13 % pairwise) than dizygotic twins (5 % probandwise and 3 % pairwise). The probandwise and pairwise concordance rates for Type 2 diabetes were 34% and 20% among monozygotic tiwns and 16% and 9 % in dizygotic twins, respectively. Heritability for Type 1 diabetes was greater than that for Type 2 where both genetic and environmental effects seemed to play a significant role.

Background To evaluate medical and dental students' utilization of electronic information resources. Methods A web survey sent to 837 students (49.9% responded). Results Twenty-four per cent of medical students and ninteen per cent of dental students searched MEDLINE 2+ times/month for study purposes, and thiry-two per cent and twenty-four per cent respectively for research. Full-text articles were used 2+ times/month by thirty-three per cent of medical and ten per cent of dental students. Twelve per cent of respondents never utilized either MEDLINE or full-text articles. In multivariate models, the information-searching skills among students were significantly associated with use of MEDLINE and full-text articles. Conclusion Use of electronic resources differs among students. Forty percent were non-users of full-text articles. Information-searching skills are correlated with the use of electronic resources, but the level of basic PC skills plays not a major role in using these resources. The student data shows that adequate training in information-searching skills will increase the use of electronic information resources.

Summary Objective: The purpose of this study is to compare whether students’ learning outcomes would be better in a designed learning environment (WebCT) than in a conventional web site (WWW) with similar course material but without special learning tools. Context: Third-year medical students in an introductory course on medical informatics at the University of Helsinki, Finland. Methods: Students were randomly assigned to a WebCT group (n = 39) and a WWW group (n = 46). The students in the WebCT group utilized the course material in general discussion groups, special discussions about lectures, quizzes and students’ own notes. The WWW group had access only to the course material. The learning outcome was assessed by administering an on-line examination and the learning experience of the students was assessed by an on-line quiz. Results: The course grade was significantly higher in the WebCT group as compared to the WWW group. This finding was more prominent among females. The students of the WebCT group also experienced significantly more improvement in collaboration with the use of computers than the students in the WWW group. Conclusions: Based on our results, web-based learning seems to be more effective when students are provided with specially designed learning tools. © 2005 Elsevier Ireland Ltd. All rights reserved.

The traditional role of twin studies has been to assess the relative role of genetic factors as a first step in defining the genetic architecture of complex traits. This has been based on the realization that monozygotic pairs (MZ) share all their genes, while dizygotic pairs (DZ) share 50% of their genes on average. Thus, greater similarity of MZ pairs compared to DZ pairs has been taken as prima facie evidence of the role of genetic factors. This is true provided the environmental similarity of MZ pairs is not greater than for DZ pairs for effects relevant to the trait in question. This first step in genetic studies was carried out long ago in many research areas, but not in others. More detailed knowledge of the genetic architecture of traits is then obtained by other means. In this paper, we give a brief overview of some results for metabolic diseases (ischaemic heart disease, hypertension, subarachnoid haemorrhage, NIDDM and IDDM) using the classical twin approach in a large, unselected population-based twin cohort. We also outline approaches to using twins that we believe will continue to be useful, particularly for the study of environmental effects.