Alzheimer Disease: Johansen C

Schüz J, Waldemar G, Olsen JH, Johansen C. · Institute of Cancer Epidemiology, Danish Cancer Society, Copenhagen, Denmark. · PLoS One. · Pubmed #19194493 links to  free full text

Abstract: The aim of this study was to investigate a possible link between cellular telephone use and risks for various diseases of the central nervous system (CNS). We conducted a large nationwide cohort study of 420 095 persons whose first cellular telephone subscription was between 1982 and 1995, who were followed through 2003 for hospital contacts for a diagnosis of a CNS disorder. Standardized hospitalization ratios (SHRs) were derived by dividing the number of hospital contacts in the cohort by the number expected in the Danish population. The SHRs were increased by 10-20% for migraine and vertigo. No associations were seen for amyotrophic lateral sclerosis, multiple sclerosis or epilepsy in women. SHRs decreased by 30-40% were observed for dementia (Alzheimer disease, vascular and other dementia), Parkinson disease and epilepsy among men. In analyses restricted to subscribers of 10 years or more, the SHRs remained similarly increased for migraine and vertigo and similarly decreased for Alzheimer disease and other dementia and epilepsy (in men); the other SHRs were close to unity. In conclusion, the excesses of migraine and vertigo observed in this first study on cellular telephones and CNS disease deserve further attention. An interplay of a healthy cohort effect and reversed causation bias due to prodromal symptoms impedes detection of a possible association with dementia and Parkinson disease. Identification of the factors that result in a healthy cohort might be of interest for elucidation of the etiology of these diseases.

Håkansson N, Gustavsson P, Johansen C, Floderus B. · Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. · Epidemiology. · Pubmed #12843765 No free full text.

Abstract: BACKGROUND: Previous work has suggested an increase in risk of amyotrophic lateral sclerosis (ALS) and Alzheimer's disease among workers exposed to extremely low-frequency magnetic fields (ELF-MF). We evaluated the relation between ELF-MF from occupational exposures and mortality from neurodegenerative diseases. METHODS: The study was based on a cohort of Swedish engineering industry workers, comprising 537,692 men and 180,529 women. The cohort was matched against the 3 most recent censuses and The Causes of Death Registry. Levels of ELF-MF exposure were obtained by linking occupation according to the censuses to a job exposure matrix. We used 4 levels of exposure and considered both the primary and contributing causes of death, 1985-96. RESULTS: The risk of Alzheimer's disease as primary or contributing cause of death increased with increasing exposure to ELF-MF among both men and women, with a relative risk (RR) of 4.0 and a 95% confidence interval (95% CI) of 1.4-11.7 in the highest exposure group for both sexes combined. There was a RR of 2.2 (95% CI: 1.0-4.7) for ALS in the highest exposure group with the suggestion of an exposure-response relationship. No evidence of increased risk was seen for Parkinson's disease or multiple sclerosis. CONCLUSIONS: The findings support previous observations of an increased risk of Alzheimer's disease and ALS among employees occupationally exposed to ELF-MF. Further studies based on morbidity data are warranted.

Johansen C. · Institut for Epidemiologisk Kraeftforskning, Kraeftens Bekaempelse, Strandboulevarden 49, DK-2100 København. · Ugeskr Laeger. · Pubmed #11810798 No free full text.

Abstract: INTRODUCTION: Occupational exposure to electromagnetic fields has been associated with neurological diseases, such as amyotrophic lateral sclerosis, senile dementia, Parkinson's disease and Alzheimer's disease. MATERIAL AND METHOD: I studied the incidence of disease in the central nervous system in 30,631 persons employed at Danish electric companies between 1900 and 1993. I linked the cohort to the nationwide, population-based Danish National Register of Patients and compared the number of cases of these diseases found between 1978 and 1993 with the corresponding rates in the general population. In addition, I fit the data on utility workers to a multiplicative Poisson regression model in relation to estimated levels of exposure to 50 Hz electromagnetic fields. RESULTS: Overall, there was an increase in the risk of senile dementia and motor neuron diseases combined. The incidences of Parkinson's disease, Alzheimer's disease and other diseases of the central nervous system were essentially unrelated to exposure to electromagnetic fields. A decreased risk of epilepsy compared with the general population probably reflects a healthy worker effect; I observed an increased risk of epilepsy based on internal comparisons. DISCUSSION: The increased risk of senile dementia and motor neuron diseases may be associated with above average levels of exposure to electromagnetic fields.

Johansen C. · Institute of Cancer Epidemiology, the Danish Cancer Society, Copenhagen. · Epidemiology. · Pubmed #10955406 No free full text.

Abstract: Occupational exposure to electromagnetic fields has been associated with neurological diseases such as amyotrophic lateral sclerosis, senile dementia, Parkinson disease, and Alzheimer disease. I studied the incidence of central nervous system diseases in 30,631 persons employed in Danish utility companies between 1900 and 1993. I linked the cohort to the nationwide, population-based Danish National Register of Patients and compared the numbers of cases of these diseases observed between 1978 and 1993 with the corresponding rates in the general population. In addition I fit to the data on utility workers a multiplicative Poisson regression model in relation to estimated levels of exposure to 50-Hz electromagnetic fields. Overall, there was an increase in risk for senile dementia and motor neuron diseases combined. The incidences of Parkinson disease, Alzheimer disease, and other diseases of the central nervous system were essentially unrelated to exposure to electromagnetic fields. A decreased risk of epilepsy compared with the general population probably reflects a healthy worker effect; I observed an increased risk of epilepsy based on internal comparisons. The increased risk for senile dementia and motorneuron diseases may be associated with above-average levels of exposure to electromagnetic fields.