TABLE 1.

Postshift Urinary Metabolite Measurements of U.S. Air Force Personnel

Exposure group	n	Mean	Standard deviation	Minimuma	Maximum	N > LODb (%)
BMA (ng/ml)
Low	593c	8.7	7.8	0.35	32.5	58 (95.1)
Medium	38	8.9	8.1	0.35	35.5	37 (97.4)
High	98	11.9e	7.7	0.35	33.9	96 (98.0)
PMA (ng/ml)
Low	61	0.5	0.3	0.35	1.5	12 (19.7)
Medium	38	0.5	0.4	0.35	2.7	9 (23.7)
High	98	1.0e,f	1.6	0.35	12.5	33 (33.7)
MEAA (μg/ml)d
Low	61	0.07	0.02	0.07	0.2	2 (3.3)
Medium	38	0.42e	0.89	0.07	4.8	13 (34.2)
High	98	6.8e,f	15.2	0.07	110	92 (93.9)
BMA (ng/mg creatinine)
Low	59c	7.8	13.4	0.36	1.5	—
Medium	38	5.2	3.5	0.47	2.7	—
High	98	4.9	4.9	1.32	16.6	—
PMA (ng/mg creatinine)
Low	61	0.44	0.34	0.10	1.5	—
Medium	38	0.44	0.57	0.09	3.4	—
High	98	0.44	0.54	0.07	3.5	—
MEAA (μg/mg creatinine)
Low	61	0.08	0.07	0.02	0.30	—
Medium	38	0.26e	0.44	0.02	2.3	—
High	98	2.9e,f	6.4	0.02	45	—
Creatinine (mg/ml)
Low	61	1.50	0.81	0.23	3.59	—
Medium	38	1.76	0.91	0.10	4.04	—
High	98	2.48	1.10	0.25	5.50	—

^aMinimum = minimum concentration; 0.35 ng/ml for BMA and PMA and 0.07 μg/ml for MEAA.

^bLOD = limit of detection; 0.5 ng/ml for BMA and PMA and 0.1 μg/ml for MEAA. Samples with less than the LOD are coded as 0.35 ng/ml for BMA and PMA and 0.07 μg/ml for MEAA for use in statistical evaluation only. This is the LOD divided by the square root of 2 (see the text for a full explanation).

^cTwo individuals from the low exposure group had BMA levels far exceeding any other measured value: 144 and 244 ng/ml. These were treated as outliers for purposes of determining the mean and standard deviation for this workgroup; thus, n = 59 for the mean and standard deviation (see the text for a full explanation).

^dMEAA data alone reported previously (B’Hymer et al. 2012).

^eThe difference from the low exposure (control) group was statistically significant, p < .05.

^fThe difference from the medium exposure group was statistically significant, p < .05.