Amyotrophic Lateral Sclerosis (ALS) in Western Pennsylvania (Pa) 2008-2009):
Examining the Role of Gender and Age at Onset
Objectives: ALS is a rare disease with a global incidence of 1-2 cases per 100,000 persons and an estimated prevalence of 5 per 100,000. Median survival is approximately 2-4 years after onset of ALS. There is currently no treatment available to prevent or reverse this devastating disease. The etiology of ALS is unknown although environmental/occupational risk factors are thought to play a role. Western Pa provides a suitable setting for studying ALS due to the history of the coal and steel industry, occupational exposures, as well as environmental hazards. The purpose of this case series is to investigate personal, occupational and environmental risk factors for ALS in Western Pa.
Methods: A descriptive analysis of ALS cases was conducted by age at onset, gender, race and area of residence for individuals diagnosed at the University of Pittsburgh Medical Center’s Center for ALS Research. Age, race, gender, sex, and county matched controls will be obtained. Time of onset and disease severity is also being assessed. A Standardized Mortality ratio was calculated comparing ALS deaths identified through the PADOH with Pa deaths as a whole for 2006-2008. Geographic information systems (GIS) techniques will be used to relate proximity of subjects’ residences to surrounding toxic waste sites and major landfill areas.
Results: Subjects presently identified include 76 ALS cases, 21 years of age and over. Fourteen (18%) are from the City of Pittsburgh. The mean age of onset for males is 58.4 + 12.3 and 64.7 + 13.0 for women, p=0.037. There are 44 males and 32 females (1.4:1) (p<0.01). Caucasian’s make up 97% (72/74) of the sample, the remainder are African-American. The SMR showed a significantly elevated rate for Beaver county (SMR=1.48, 95% CI=103.6, 204.8) and nearly significant elevation for Allegheny County (SMR=113.9, 95% CI 98.1, 131.5).
Conclusions: The increased male: female ratio and the male decreased mean age of onset may reflect a reduced latency due to increases in personal and /or environmental /occupational exposures in men compared to women. The comparison of female cases to female controls will be equally important to determine if there are unique exposures within ALS cases that are “non traditional “and more reflective of a male profile of experiences. Implications for public health: The case control design will permit within gender and racial comparisons of cases to controls and may shed light on important risk factors for this disease.
For more information, please contact Dr. Evelyn O. Talbott at 412-624-3074 or eot1@pitt.edu.