Leisure Time Physical Activity Is Associated With An Increased Risk Of Als

OBJECTIVE: The aim of the present population-based study was to determine the relation between lifetime physical activity and risk of sporadic amyotrophic lateral sclerosis (ALS), using an objective approach for assessing physical activity in order to minimize recall bias. BACKGROUND: Ever since Lou Gehrig, a famous professional baseball player, died from ALS, it has been hypothesized that physical activity is a risk factor for developing ALS, fuelled by recent observations that professional soccer players and Gulf War veterans are at increased risk of ALS. DESIGN/METHODS: 636 incident ALS patients and 2,166 controls filled in semi-structured questionnaires to obtain lifetime history of occupations, sports, and hobbies. All reported activities were assigned a metabolic equivalent score (MET) based on the Compendium of Physical Activities. The MET is a physiological measure expressing the energy cost of physical activities. Odds ratios for ALS with levels of cumulative occupational and leisure time physical activity were calculated, adjusted for gender, age, level of education, premorbid body mass index (BMI), current alcohol consumption and current smoking. RESULTS: Higher levels of leisure time physical activity were associated with an increased risk of ALS (adjusted OR 1.08, 95% CI 1.02-1.14, P = 0.008). However, no association between ALS and occupational activity or vigorous physical activities, such as marathons and triathlons, was found. Moreover, dividing the cumulative measures of physical activity in quartiles showed no dose-response relationship between physical activity and ALS. CONCLUSIONS: The present population-based case-control study strengthens the hypothesis that physical activity itself is not causative per se, although higher levels of leisure time physical activity were associated with an increased risk of ALS, but rather that being athletic is a phenotypic expression of a genetic profile that increases the risk of ALS. Disclosure: Dr. Seelen has nothing to disclose. Dr. Huisman has nothing to disclose. Dr. de Jong has nothing to disclose. Dr. Dorresteijn has nothing to disclose. Dr. van Doormaal has nothing to disclose. Dr. Van Der Kooi has nothing to disclose. Dr. De Visser has received research support from Biogen Idec. Dr. Schelhaas has nothing to disclose. Dr. Van den Berg has received personal compensation for activities with Baxter, Biogen Idec and Cytokinetics as a consultant and/or participant on an advisory board. Dr. Veldink has nothing to disclose.