ASSOCIATION BETWEEN CREATININE-ADJUSTED AND UNADJUSTED URINE COTININEVALUES IN CHILDREN AND THE MOTHERS REPORT OF EXPOSURE TO ENVIRONMENTAL TOBACCO-SMOKE

Objective: To examine the association between parents' report of their child's secondhand smoke exposure and various adjustments of cotinine concentrations in random urine samples. Methods: Urine cotinine and c reatinine were measured in 109 six to 11-year-old children from predom inantly upper middle-class families. Cotinine values were considered a s: (a) unadjusted, (b) as a cotinine/creatinine ratio, (c) as adjusted based on a regression relationship between cotinine and creatinine, a nd (d) and (e) as a cotinine/creatinine ratio adjusted for age and sex . Results: Little overlap in cotinine values occurred between exposed and nonexposed children, and a dose-response relationship was noted be tween the parental report and the urine cotinine values (r = 0.67). A modest improvement occurred in the correlation when the cotinine/creat inine ratio was considered. Considering exposure to cigarette smoke ou tside the home as well as in the household only improved the correlati on when the former exposure was heavy. A high degree of concordance ex ists between the parents' report of exposure and the child's urine cot inine. Conclusions: The value of adjusting this biochemical parameter by various means may be a function of the particular sample being inve stigated, suggesting no one method is universally appropriate.