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Table 5 Pearson correlations for performance Criterion A across the range of adjustment methods investigated for NHANES 2009–2012 (CDC, 2015) (testing dataset)

From: Assessing urinary flow rate, creatinine, osmolality and other hydration adjustment methods for urinary biomonitoring using NHANES arsenic, iodine, lead and cadmium data

Adjustment method

rp (95 % CI)

Pb

Cd

AsIMM

I

Unadjusted

-0.33*** (-0.41, -0.24)

 

-0.25*** (-0.34, -0.26)

 

-0.37*** (-0.45, -0.28)

-0.39*** (-0.47, -0.31)

Creatinine

0.18*** (0.09, 0.27)

b

0.18*** (0.09, 0.27)

b

0.32*** (0.24-0.41)

0.09 (-0.001, 0.19)

Osmolality

-0.001 (-0.10, 0.09)

a

0.02 (-0.07, 0.12)

a

0.10* (0.003-0.19)

-0.09 (-0.18, 0.004)

ER

0.52*** (0.45, 0.59)

 

0.47*** (0.39, 0.54)

 

0.70*** (0.65, 0.74)

0.45*** (0.37, 052)

ERBW

0.43*** (0.35, 0.50)

 

0.42*** (0.34, 0.50)

 

0.60*** (0.53, 0.66)

0.35*** (0.26, 0.43)

UFRA

0.01 (-0.08, 0.11)

a

-0.01 (-0.10, 0.09)

a

-0.03 (-0.12, 0.07)

-0.01 (-0.10, 0.09)

UFRB

0.18*** (0.09, 0.27)

b

0.22*** (0.13, 0.31)

b

 -

 -

  1. Correlations were calculated on natural log transformed data. *** and * denote significance to p < 0.001 and <0.05, respectively. Bold font denotes the best performing adjustment method for each analyte. Correlations share a letter when not significantly different from one another