Lifestyle Factors and Risk of Amyotrophic Lateral Sclerosis: A Case-Control Study in Japan

Received 19 March 2008; accepted 15 January 2009. published online 03 April 2009.

Purpose

We examined the associations between lifestyle factors and the risk of amyotrophic lateral sclerosis (ALS) using a case-control study in Aichi Prefecture, Japan.

Methods

The study comprised 183 ALS patients diagnosed by the El Escorial World Federation of Neurology criteria as well as 366 gender- and age-matched controls randomly selected from the general population with the use of the basic register of residents. Detailed information on lifestyle factors was obtained through a mailed self-administered questionnaire. The strength of association between ALS and a potential risk factor was assessed by calculating odds ratios (ORs) and 95% confidence intervals (CIs).

Results

Vigorous physical activity, self reported stress, a type A behavior pattern, and less frequent intakes of green-yellow vegetables were significantly associated with increased risk of ALS, whereas smoking and drinking habits were not. The greatest effect on risk for ALS was posed by the combination of a type A behavior pattern and less frequent intakes of green-yellow vegetables (adjusted OR, 11.2; 95% CI, 3.8 to 33.0).

Conclusion

These data suggested that imbalances between excessive productions of oxidants as patient-specific factors and a diminished or missing antioxidant defense system in motor neurons may increase the risk of ALS.

Key Words: Amyotrophic Lateral Sclerosis, Epidemiology, Case-Control Study Personality, Oxidants, Antioxidants

Selected Abbreviations and Acronyms: ALS, amyotrophic lateral sclerosis, MET, metabolic rate, OR, odds ratio, CI, confidence interval

a Department of Public Health, Aichi Prefectural College of Nursing and Health

b Department of Neurology, Wakayama Medical University

c Molecular Biostatistics Research Team, Research Center for Charged Particle Therapy, National Institute of Radiological Science

d Department of Public Health, St. Mary's College

e Department of Epidemiology, Tokyo University

f Department of Technology Assessment and Biostatistics, National Institute of Public Health

g Department of Public Health, Fukuoka University School of Medicine

h Department of Hygiene, Hyogo College of Medicine

i Department of Epidemiology, Juntendo University School of Medicine

j Department of Public Health, Saitama Medical School

Address correspondence and reprint requests to: Kazushi Okamoto, MD, Aichi Prefectural College of Nursing and Health, Togoku, Kamishidami, Moriyama-ku, Nagoya 463-8502, Japan. Tel: +81-52-736-1401; Fax: +81-52-736-1415.

PII: S1047-2797(09)00047-7

doi:10.1016/j.annepidem.2009.01.015

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