Health risks of limited-contact water recreation.
BACKGROUND
Wastewater-impacted waters that do not support swimming are often used for boating, canoeing, fishing, kayaking, and rowing. Little is known about the health risks of these limited-contact water recreation activities.


OBJECTIVE
We evaluated the incidence of illness, severity of illness, associations between water exposure and illness, and risk of illness attributable to limited-contact water recreation on waters dominated by wastewater effluent and on waters approved for general use recreation (such as swimming).


METHODS
The Chicago Health, Environmental Exposure, and Recreation Study was a prospective cohort study that evaluated five health outcomes among three groups of people: those who engaged in limited-contact water recreation on effluent-dominated waters, those who engaged in limited-contact recreation on general-use waters, and those who engaged in non-water recreation. Data analysis included survival analysis, logistic regression, and estimates of risk for counterfactual exposure scenarios using G-computation.


RESULTS
Telephone follow-up data were available for 11,297 participants. With non-water recreation as the reference group, we found that limited-contact water recreation was associated with the development of acute gastrointestinal illness in the first 3 days after water recreation at both effluent-dominated waters [adjusted odds ratio (AOR) 1.46; 95% confidence interval (CI): 1.08, 1.96] and general-use waters (1.50; 95% CI: 1.09, 2.07). For every 1,000 recreators, 13.7 (95% CI: 3.1, 24.9) and 15.1 (95% CI: 2.6, 25.7) cases of gastrointestinal illness were attributable to limited-contact recreation at effluent-dominated waters and general-use waters, respectively. Eye symptoms were associated with use of effluent-dominated waters only (AOR 1.50; 95% CI: 1.10, 2.06). Among water recreators, our results indicate that illness was associated with the amount of water exposure.


CONCLUSIONS
Limited-contact recreation, both on effluent-dominated waters and on waters designated for general use, was associated with an elevated risk of gastrointestinal illness.
Division of Environmental and Occupational Health Sciences, UIC School of Public Health, 2121 W. Taylor, M/C 922, Chicago, IL 60612 USA. sdorevit@uic.edu
Samuel
S
Dorevitch
Preethi
P
Pratap
Meredith
M
Wroblewski
Daniel O
DO
Hryhorczuk
Hong
H
Li
Li C
LC
Liu
Peter A
PA
Scheff
D000293:Adolescent; D000328:Adult; D000465:Algorithms; D002641:Chicago / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D002947:Cities / Q000453:epidemiology; D015331:Cohort Studies; D015817:Eye Infections / Q000453:epidemiology / Q000382:microbiology; D005260:Female; D005500:Follow-Up Studies; D005767:Gastrointestinal Diseases / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D015994:Incidence; D007223:Infant; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011998:Recreation; D018570:Risk Assessment; D012720:Severity of Illness Index; D016019:Survival Analysis; D013550:Swimming; D014871:Water Microbiology; D060753:Water Quality; D055815:Young Adult