1. Journal reviews
이승호

2. Journal
hEX-Tox

3. Introduction Biomarkers in specific matrices
UER (urinary excretion rate)
: Chemical conc. * volume / duration rate
Creatinine adjustment
: better relation with blood/serum conc.
In case of children, HOWEVER, smaller blood vol. and lower urinary creatinine level
 increase the adjusted concentration level
hEX-Tox

4. Introduction Guideline values WHO : 30 ~ 300 mg/dL
US. Department of Transportation
: < 5 mg/dL and ~1.020 SG
Influential Factor
Increasing age
GFR(glomerular filtration rate)
Seasonal variation
hEX-Tox

5. Objectives
To document the normal range of urinary creatinine concentrations among various demographic groups
To evaluate the influence demographic variations in creatinine concentrations
To explore methods to appropriately adjust urinary analytes using creatinine that take into account demographic differences
hEX-Tox

6. Materials and Methods NHANES Ⅲ (1988-1994) Creatinine analysis
Conducted by NCHS of CDC
US population (non-Hispanic white, non-Hispanic black, Mexican American) ≥ 2 months of age
A household interview, physical examination
Creatinine analysis
Beckman Synchron AS/ASTRA clinical analyzer
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7. Materials and Methods Demographic covariates Health status definitions
Age: 6-11, 12-19, 20-29, 30-39, 40-49, 50-59, 60-69, ≥ 70 years
Non-Hispanic black, Non-Hispanic white, Mexican American, others
Health status definitions
tested for physical conditions
GFR: 신장기능검사의 지표 glomerular filtration rate
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8. Statistical analysis SAS 8, SUDAAN
Survey sample weights for cluster design (Proc descript)
Skewed to the higher values (right), not log-transformation
Analysis of covariance: to correct demographic covariates
Multiple linear regression: to study the influence of variables (race, sex, age, BMI, FFM, clinical parameters)
N=22,245 creatinine values in urine
Evaluated the potential effects of differential nonresponse
FFM is calculated by sex, and age-specific equation (height, weight, age, sex, react
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9. Results
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10. Results Non-Hispanic blacks greater than others (Fig 1.)
※ Normal range (30 ~ 300 mg/dL)
Non-Hispanic blacks greater than others (Fig 1.)
Since 12% of all children below than guideline  should be re-evaluated
Up to 8% of all had < 30 mg/dL, under 3% had > 300 mg/dL
Urinary creatinine between morning and evening is significantly differed (Table 4.)
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11. Results
≥ 20 subjects,
almost of independent variables were significant interaction terms ( depends on the race & age group, bias exists.)
Those who suffer diabetes have lower than others, and the magnitude varied.
Kidney dysfunction
All age subjects, (Table 5.)
Race, sex, age group & BMI were significant interaction term ( age group * (race, sex))
Age groups differ across the race
The higher FFM, the smaller BMI effect
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12. Discussion WHO guideline  for occupational monitoring
Low conc. too dilute and impair detection of toxicants.
High conc. Dehydration (kidney’s secretion, excretion, reabsorption)
Typical rules for outliers: 1~99 % (or 5~95 %) of popul.
In specific group, it would make bias (Mexican female over 70 yr.)
This criteria might be established using less diversity workforce such as non-Hispanic white male
 women, other ethnic, and older workers need to be considered
hEX-Tox

13. Discussion
morning urine (no info for first voids) > afternoon & evening
Chemical exposures among children and adults are differ,
so that creatinine adjustment elevates the urinary conc. in children compare to adults.
Lean muscle mass (produces the majority of creatinine)
Fat free mass (FFM) associate with creatinine (r=0.222)
Separate normal/reference range for specific rather for total
Model1. predictor of exposure - possibility - solution
Model2. predictor of disease - possibility - solution
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14. Discussion & Conclusions
Limitation
FFM and creatinine data existed only for > 12yr.
No dietary data
Not evaluate for children < 6 yr.
Not exactly first morning void samples
Not established the upper bound CI for 90th percentiles
Conclusion
1. ( fill in the blank )
2. ( fill in the blank )
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15. QnA ?
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