Purpose:
A persistent increase in AK has been observed in Chicago since June 2003. Recent EPA regulations decreased allowable disinfection byproducts in the domestic water supply, potentially shifting the microbial risk balance. The purpose of this analysis is to investigate the association between tap water exposure and AK, and to investigate Acanthamoeba presence in the water supply.
Methods:
All cases presenting at the UIC Cornea Service between 6/03 and 4/06 were recruited for a matched case control study (1:M), performed between 4/06 and 11/06. Controls were selected from the UIC Cornea Service and individually matched on use of contact lenses (CL), age (± 5 years), and date-of-service (± 1 month). Subjects agreeing to participate provided water samples and completed surveys to explore water exposures as well as CL solution and hygiene issues. Unconditional logistic regression was performed after breaking the match with SAS, v.9.1.3, PROC LOGISTIC (Cary, NC).
Results:
34 of 47 (72.3%) cases participated, and 77 of 115 (66.1%) of contacted controls participated. Table 1 presents age and contact lens adjusted odds ratio for water exposure variables.*vs. never in past monthvs. good, fair or poor
Conclusions:
Data support previously known water-related risk factors, and suggest a weak association may exist between tap water exposure and AK, particularly with soft CL use. Further study to maximize power is warranted to better understand the association and determine the effect of covariates.
Keywords: Acanthamoeba • clinical (human) or epidemiologic studies: risk factor assessment • pathobiology