ORIGINAL ARTICLE Risk Factors for Alzheimer Disease: A Population-Based Case-Control Study in Istanbul, Turkey Hande Harmanci, MD, Murat Emre, MD, Hakan Gurvit, MD, Basar Bilgic, MD, Hasmet Hanagasi, MD, Edip Gurol, MD, Huseyin Sahin, MD, and Sule Tinaz, MD Summary: The objective is to study risk factors for Alzheimer dis- ease (AD) in Istanbul, Turkey. This is a population-based case- control study. We screened people over age 70 in the community for cognitive impairment. The screen positives and a proportion of screen negatives underwent neurologic examination in the second phase. Cases were 57 “probable” AD patients and controls were 127 cogni- tively normal individuals identified by neurologic examination. Odds ratios (OR) were calculated using multivariate logistic regression analysis. Having a university/college degree had a protective effect on AD risk (OR = 0.10, 95% confidence interval [CI] = 0.02–0.50). Ex- posure to occupational electromagnetic field had an OR of 4.02 (95% CI = 1.02–15.78). Use of electricity for residential heating also showed elevated risk (OR = 2.77, 95% CI = 1.12–6.85). Our results suggest that having a higher education is protective from AD and that electromagnetic field exposure at work or at home is a significant risk factor. Key Words: risk factors, education, electromagnetic field, EMF, Turkey (Alzheimer Dis Assoc Disord 2003;17:139–145) A lzheimer disease (AD) is becoming a major public health problem as populations age and the proportion of the aged constitute a growing proportion of the population. The high prevalence 1–3 and incidence rates, 4–5 combined with the social and economic burden, rank AD high in the list of important health problems of the modern society. A steady stream of studies has been published for the risk factors of AD for the last two decades. A review article 6 groups these studies into four types: those that have examined familial and genetic factors (gender, family history, APOE, etc), clinical/illness-related risk factors (Down syndrome, thyroid disease, head injury, etc), exposure to environmental hazards (estrogen replacement therapy, nonsteroidal anti inflammatory drugs [NSAIDs], tobacco, alcohol, electromagnetic fields (EMFs), aluminum, etc.), and sociodemographic characteris- tics (education, occupation, rural area of residence, household characteristics, etc) as risk factors. Among those, only age and positive family history are considered as definite risk factors. Most of the publications on AD have come from the de- veloped world. Developing countries have not been able to re- port reliable data on dementias and AD, possibly because they have less resources for research and health services for the care of the elderly. The Indo-U.S. study 7 is one of the few from a developing country, and it reports lower prevalence figures compared with developed nations, with possible explanations of low overall life expectancy, short survival with the disease, and low age-specific incidence potentially due to differences in the underlying distribution of risk and protective factors compared with populations with higher prevalence. One pro- spective study 8 examines incidence rate differences between Nigerians and African Americans living in Illinois and reports significant differences between the two populations with Ni- gerians having lower incidence rates. We here present the first AD risk factor study from Tur- key as part of the Turkish Alzheimer Prevalence Study. METHODS This study was carried out in Kadikoy, Istanbul, Turkey. The sample for the cross-sectional part of this study was deter- mined as 1067 individuals 70 years of age or older randomly selected from population registries (records of the muhtars’ 1 list). After obtaining addresses from muhtars, all subjects were visited in their homes by a group of trained interviewers. Those who were not found at home were visited two more times. As- suming a community prevalence of 50%, we determined that Received for publication August 7, 2002; accepted March 8, 2003. From the Department of Public Health (Dr Harmanci), Marmara University Medical Faculty, and the Department of Neurology (Drs Emre, Gurvit, Bilgic, Hanagasi, Gurol, Sahin, and Tinaz), Istanbul University, Istanbul Medical Faculty, Istanbul, Turkey. This project was supported by a non-restricted research grant from Novartis A.S Turkey. Reprints: Dr. Hande Harmanci, Marmara University Medical Faculty, Depart- ment of Public Health, Haydarpasa 81326, Istanbul, Turkey (e-mail: hharmanci@marmara.edu.tr). Copyright © 2003 by Lippincott Williams & Wilkins 1 A muhtar is an elected official responsible mainly of keeping records of the population living in a defined geographical area. The records contain the following information: name, address, date and place of birth, mother’s and father’s names. Alzheimer Dis Assoc Disord • Volume 17, Number 3, July–September 2003 139