Zoreh Davanipour

Elevated risk of Alzheimer's disease among workers with likely electromagnetic field exposure.

We conducted a case-control study of the possible association of occupations with likely exposure to electromagnetic fields and Alzheimers disease (AD) with patients from the Alzheimer Disease Treatment and Diagnostic Center, Rancho Los Amigos Medical Center, Downey, CA. Patients with definite or probable AD were the case subjects (86 male, 240 female). Patients with cognitive impairment/dementia other than vascular dementia were control subjects (76 male, 76 female). The study was limited to patients who were at least age 65 at the time of their first examination at Rancho Los Amigos. The odds ratio for both sexes combined was adjusted for sex, education, and age at onset. The odds ratio for males was adjusted only for age at onset, and the odds ratio for females was adjusted for both education and age at onset. The adjusted odds ratio for both sexes was 3.93 (p = 0.006), 95% CI = (1.5 to 10.6). For males the adjusted odds ratio was 4.90 (p = 0.01), 95% CI = (1.3 to 7.9), and for females the adjusted odds ratio was 3.40 (p = 0.10), 95% CI = (0.8 to 16.0). These results are consistent with previous findings regarding the hypothesis that electromagnetic field exposure is etiologically associated with the occurrence of AD. NEUROLOGY 1996;47: 1477-1481

Lack of association of apolipoprotein E allele ϵ4 with late‐onset Alzheimer's disease among Finnish centenarians

Article abstract—No association between Alzheimers disease (AD) and apolipoprotein E type ϵ4 (ApoE ϵ4) phenotype was found among centenarians in Finland (N = 179). The data are based on ascertainment of all centenarians in Finland in 1991. All examinations were conducted during 1991. The diagnoses of dementia and AD were based on clinical grounds, conforming to DSM-III-R and NINCDS-ADRDA criteria. The percentage of ApoE ϵ4 alleles among the centenarians was 8.7% (31 of 358 alleles). This is significantly lower than percentages found in younger Finnish populations. Thirty (16.8%) of the 179 centenarians were ϵ4 allele carriers. One hundred fifty-one (84.4%) of the centenarians were women. Twenty-eight (18.5%) of the women had at least one ϵ4 allele, as did two (7.1%) of the men. The prevalence of clinically diagnosed AD was 26.8%; 44% of the subjects were cognitively normal, 23% had signs of cognitive decline or at most mild dementia (with no differential diagnosis), and 6% had a dementia clinically diagnosed as being due to some cause other than AD. For AD cases versus cognitively normal subjects, the odds ratio associated with being a carrier of the ϵ4 allele was 1.34 (p = 0.64; 95% CI = [0.5, 3.31). Among women, the odds ratio was 0.99 (p = 1.0; 95% CI = [0.4, 2.6]). There were fewer, but not significantly so, ϵ4 carriers among subjects with cognitive decline or at most mild dementia (12.2%) than there were among the cognitively normal subjects (16.5%). Ten (10.4%) of the 96 alleles belonging to AD cases were ϵ4, and 8.9% (14/158) of the alleles belonging to the cognitively normal subjects were ϵ4. This difference is highly nonsignificant. There was only one individual who was homozygous for the ϵ4 allele. She was cognitively normal. Among the 28 men in the study there were only two carriers of the ϵ4 allele; consequently, analyses for men have little power. These results clearly show that the ϵ4 allele does not necessarily lead to AD even near the (current) upper age-limit of life. When combined with previous findings, these results suggest that the association of the ApoE ϵ4 allele with AD may be age-dependent and that the ApoE ϵ4 allele might accelerate the AD dementing process rather than be a direct etiologic agent or a predisposing genetic factor.

Creutzfeldt‐Jakob disease Possible medical risk factors

To explore possible risk factors in the past medical history of patients with Creutzfeldt-Jakob disease (CJD), we conducted a case-control study among 26 cases and 40 matched controls. Statistically significant odds ratios were obtained for intraocular pressure testing; injury to or surgery on the head, face, or neck; and trauma to other parts of the body. The odds ratios were nearly significant for head trauma and procedures requiring sutures. These data suggest that the CJD agent may be acquired by inoculation through injury or during surgery, and perhaps on certain absorbable sutures of animal origin. The tonometer used for glaucoma testing may also be a vehicle of transmission.

Electromagnetic field exposure may cause increased production of amyloid beta and eventually lead to Alzheimer's disease

Based on earlier work by several groups, in 1989 Selkoe and colleagues [1,2] suggested that amyloid beta (A beta) found in cerebral blood vessels, skin tissue, and elsewhere might come from a peripheral source and might contribute to the Alzheimers disease (AD) pathogenesis. Independently, using four clinical series and four different types of controls, Sobel et al. [3,4] found that having a primary occupation likely to have resulted in medium-to-high extremely low frequency (ELF) electromagnetic field (EMF) exposure significantly increases the risk of AD. The means by which EMF (or any other) exposure might precipitate the Alzheimer pathogenesis are currently unknown. One possibility is that EMF exposure might affect the peripheral or neuronal processing of the amyloid precursor protein. We outlined a cascade of events as a hypothesis of how EMF exposure may be associated with AD onset. In two published papers, Sobel et al. [3,4] found elevated risk of AD associated with having a primary occupation likely to have resulted in medium-to-high EMF exposure. The four clinical series examined were widely separated by time or distance and the data were collected without any consideration of EMF exposure. (Table 1) provides information about patients and control subjects and the ascertainment period for each series. The total number of AD patients in the four series was 713 and the total number of control subjects was 627. Surrogate-derived data were used for all patients and for control subjects from Finnish Series 1 and the Rancho Los Amigos Medical Center (RLAMC), Los Angeles, series because these subjects were demented. Following standard practice, we defined high EMF exposure as averaging above 10 milligauss (mG) or often above 100 mG and medium EMF exposure as averaging between 2 and 10 mG or often above 10 mG. We classified all other EMF exposures as low. The …

A case-control study of occupational magnetic field exposure and Alzheimer's disease: results from the California Alzheimer's Disease Diagnosis and Treatment Centers

BackgroundA few studies have investigated a possible relationship between Alzheimers disease (AD) and occupations with extremely low frequency magnetic field (MF) exposure. The purpose of this study was to further evaluate this possible association in a large patient population with expert diagnoses.MethodsSubjects came from the 8 of the 9 California Alzheimers Disease Diagnostic and Treatment Centers not previously used in an earlier study. Cases had probable or definite AD; controls primarily had a dementia-related problem other than vascular dementia (VaD) and some were not demented upon expert examination. Occupations were classified as having low, medium or high MF exposure, based upon previous research, replicating the exposure methodology used in our previous published studies.ResultsOccupational information was available for 98.6% of the 1527 cases and 98.5% of the 404 controls with age-at-initial examination known to be at least 65. Among cases, 2.1% and 5.4% had high and medium occupational MF exposure, respectively, while among controls the percentages were 0.8% and 3.0%. In univariate analyses, the odds ratio (OR) for subjects with medium or high MF exposures combined was 2.1 (p < 0.01), while for high exposure alone the OR was 2.9 (p < 0.08). Two models were used in multivariate analyses, with gender, stroke, and either age-at-onset or age-at-initial examination as covariates. The ORs for MF exposure varied little between the two models: 2.2 (p < 0.02) and 1.9 (p < 0.03) for medium or high exposure; 2.7 (p < 0.11) and 3.2 (p < 0.12) for high exposure. OR estimates for females were higher than for males, but not significantly higher. There were no material differences between the ORs resulting from univariate and multivariate analyses.ConclusionElevated occupational MF exposure was associated with an increased risk of AD. Based on previous published studies, the results likely pertain to the general population.

APOE alleles in Alzheimer's disease and vascular dementia in a population aged 85+

Apolipoprotein E genotyping was carried out in a stratified random sample of 52 patients with Alzheimers disease, 48 patients with vascular or mixed dementia, and 49 nondemented controls in a population-based study of people aged 85 and older (the Vantaa 85+ Study). Our results indicate that the apolipoprotein E epsilon 4 allele is associated with approximately a twofold increase in clinically diagnosed Alzheimers disease in this very old general population aged 85+. When combined with previous studies, our data also suggest that the association is decreasing with age. In contrast, there appears to be no relation between apolipoprotein E alleles and clinically diagnosed vascular dementia.

EMF exposure assessment in the Finnish garment industry: evaluation of proposed EMF exposure metrics.

Recently published studies indicate that having worked in occupations that involve moderate to high electromagnetic field (EMF) exposure is a risk factor for neurodegenerative diseases, including Alzheimers disease. In these studies, the occupational groups most over-represented for EMF exposure comprised seamstresses, dressmakers, and tailors. Future epidemiologic studies designed to evaluate the possibility of a causal relationship between exposure to EMF and a neuro degenerative disease endpoint such as incidence of Alzheimers disease, will benefit from the measurement of electromagnetic field metrics with potential biological relevance. Data collection methodology in such studies would be highly dependent upon how the metrics are defined. In this research the authors developed and demonstrated (1) protocols for collecting EMF exposure data suitable for estimating a variety of exposure metrics that may have biological relevance, and (2) analytical methods for calculation of these metrics. The authors show how exposure might be estimated under each of the three prominent EMF health-effects mechanism theories and evaluate the assertion that relative exposure ranking is dependent on which mechanism is assumed. The authors also performed AC RMS magnetic flux density measurements, confirming previously reported findings. The results indicate that seamstresses, as an occupational group, should be considered for study of the possible health effects of long-term EMF exposure.

Death Certificates: An Efficient Source for Ascertainment of Creutzfeldt-Jakob Disease Cases

Case ascertainment for an epidemiologic study of Creutzfeldt-Jakob disease (CJD) can be difficult. This report investigates the efficiency of various sources of case ascertainment for CJD. Cases were identified utilizing neuropathologists, hospitals and death certificates from 11 targeted states. For the period of 1986-1988, 247 death certificates indicating a diagnosis of CJD were obtained. Only 26 potential cases were identified without death certificates. The proportion of neuropathologically confirmed cases identified by death certificates only, i.e., which were not identified through any other source, was 42%. Furthermore, 80% of all the neuropathologically confirmed cases were ascertained utilizing death certificates as a source. Of the remaining 20%, 7% were ascertained through neuropathologists only, 10% through hospitals only, 1.5% through a combination of hospitals and neuropathologists, and 1.5% through another source. The false-positive rate for death certificates with neuropathology (which may have been performed after the death certificate was filled out) was estimated to be 8.3%. The results indicate that death certificates were by far the most efficient source for initial ascertainment of potential CJD cases to be followed by verification of diagnosis.

Severe Cognitive Dysfunction and Occupational Extremely Low Frequency Magnetic Field Exposure among Elderly Mexican Americans

Aims This report is the first study of the possible relationship between extremely low frequency (50–60 Hz, ELF) magnetic field (MF) exposure and severe cognitive dysfunction. Earlier studies investigated the relationships between MF occupational exposure and Alzheimer’s disease (AD) or dementia. These studies had mixed results, depending upon whether the diagnosis of AD or dementia was performed by experts and upon the methodology used to classify MF exposure. Study Design Population-based case-control. Place and Duration of Study Neurology and Preventive Medicine, Keck School of Medicine, University of Southern California, 2 years. Methodology The study population consisted of 3050 Mexican Americans, aged 65+, enrolled in Phase 1 of the Hispanic Established Population for the Epidemiologic Study of the Elderly (H-EPESE) study. Mini-Mental State Exam (MMSE) results, primary occupational history, and other data were collected. Severe cognitive dysfunction was defined as an MMSE score below 10. The MF exposure methodology developed and used in earlier studies was used. Results Univariate odds ratios (OR) were 3.4 (P< .03; 95% CI: 1.3–8.9) for high and 1.7 (P=.27; 95% CI: 0.7–4.1) for medium or high (M/H) MF occupations. In multivariate main effects models, the results were similar. When interaction terms were allowed in the models, the interactions between M/H or high occupational MF exposure and smoking history or age group were statistically significant, depending upon whether two (65–74, 75+) or three (65–74, 75–84, 85+) age groups were considered, respectively. When the analyses were limited to subjects aged 75+, the interactions between M/H or high MF occupations and a positive smoking history were statistically significant. Conclusion The results of this study indicate that working in an occupation with high or M/H MF exposure may increase the risk of severe cognitive dysfunction. Smoking and older age may increase the deleterious effect of MF exposure.

Ocular Tonometry and Sporadic Creutzfeldt - Jakob Disease (sCJD): A Confirmatory Case-Control Study.

Aims To evaluate the hypothesis that sporadic Creutzfeldt-Jakob disease (sCJD) may be transmitted through ocular tonometry. Background The infectious agent of sCJD may be present in the cornea prior to clinical symptoms. Cornea infectiousness has been documented by cornea transplants in guinea pigs and humans. sCJD is resistant to complete inactivity by conventional sterilization techniques. Thus contact tonometry equipment is not disinfected sufficiently to kill sCJD. We previously hypothesized that contact tonometry is a sCJD risk factor. Study Design Population-based case-control study. Place and Duration of Study Department of Neurology, School of Medicine, Loma Linda University, Loma Linda, CA, USA; 4 years. Methodology An 11-state case-control study of pathologically confirmed definite sCJD cases, individually matched controls, and a sample of control surrogates was conducted. Ocular tonometry histories were obtained from case-surrogates, controls, and a sample of control-surrogates. Results The odds ratio (OR) for ever vs never having had an ocular tonometry test was statistically significant for matched and unmatched analyses for 15 through 3 years prior to disease onset, using both control self-responses and control surrogates: ORs were ∞ and 19.4 with 1-sided P-values <0.0001 and 0.003 and ORs=∞ and 11.1 with 1-sided P-values <0.003 and 0.02, respectively. ORs increased as the number of tonometry tests increased during this age period: trend test, 2-sided P-value < 0.0001. For ≥5 vs <5 tonometry tests, the OR was 5.8 (unmatched) and 3.7 (matched), 2-sided P-value<0.00005. Respondents generally could not specify the type of tonometry. There was no indication of increased tonometry testing among cases within 2 years of disease onset. Conclusions The a priori hypothesis was supported. Contact tonometry, preferred by ophthalmologists, may be capable of transmitting sCJD. Consideration should be given to using disposable instrument covers after each use. The use the disposable covers or non-contact tonometry is preferable in the absence of effective disinfectant processes at this time.