Exploratory analysis of urinary metabolites of phosphorus-containing flame retardants in relation to markers of male reproductive health

Figures & data

Figure 1. Selected scatterplots of SG-corrected urinary BDCPP concentration in relation to (A) sperm motility (r_s = −0.38, P < 0.05); (B) sperm straight line velocity (r_s = −0.57, P < 0.01); (C) sperm linearity (r_s = −0.43, P < 0.05); and (D) serum TSH (r_s = 0.33, P < 0.1).

Figure 2. Selected scatterplots of SG-corrected urinary DPHP concentration in relation to (A) sperm concentration (r_s = −0.44, P < 0.1); (B) sperm motility (r_s = −0.43, P < 0.05); (C) sperm straight line velocity (r_s = −0.57, P < 0.01); (D) sperm linearity (r_s = −0.44, P < 0.05); (E) serum inhibin b (r_s = −0.28, P = 0.2); and (F) serum prolactin (r_s = 0.50, P < 0.01).

Table 1. Adjusted* regression coefficients (95% confidence intervals) for percent change (relative to population median) in semen quality parameter, sperm motion parameter, reproductive hormone level, or thyroid hormone level associated with an interquartile range (IQR) increase in specific gravity corrected BDCPP or DPHP concentration in urine (n = 33)

	BDCPP^†		DPHP^†
	% Change (95% CI)	P value	% Change (95% CI)	P value
Sperm concentration^†	-27.3 (-57.5, 22.0)	0.22	-57.2 (-77.8, -18.8)	0.01
Sperm motility	-14.9 (-30.5, 0.8)	0.06	-20.3 (-41.1, 0.5)	0.055
Sperm morphology	-36.7 (-70.6, −3.1)	0.03	-28.1 (-76.1, 19.9)	0.24
Straight-line velocity (VSL)	-18.7 (-27.8, −9.7)	0.0002	-19.0 (-32.7, -5.3)	0.009
Curvilinear velocity (VCL)	-14.1 (-24.1, −4.2)	0.007	-7.2 (-22.2, -7.8)	0.33
Linearity (LIN)	-5.1 (-11.5, 1.3)	0.11	-12.6 (-20.1, -5.2)	0.002
FSH^†	7.2 (-15.8, 36.7)	0.55	15.5 (-16.1, 59.0)	0.35
LH^†	-2.4 (-20.0, 19.4)	0.81	21.1 (-6.2, 56.5)	0.14
Inhibin B	-5.4 (-40.2, 29.5)	0.76	-37.6 (-82.2, 7.0)	0.095
Testosterone^‡	-2.2 (-13.2, 8.8)	0.68	9.8 (-4.6, 24.3)	0.18
Estradiol	5.0 (-18.2, 28.3)	0.66	5.4 (-25.9, 36.6)	0.73
SHBG^†	-9.5 (-25.8, 10.5)	0.34	-16.1 (-36.1, 10.1)	0.20
FAI^†	4.1 (-14.7, 27.0)	0.68	27.1 (-0.6, 61.6)	0.06
Prolactin^†	6.2 (-13.0, 29.6)	0.53	19.2 (-7.7, 56.5)	0.18
Free T4	0.7 (-3.2, 4.7)	0.70	3.9 (-1.0, 8.9)	0.12
Total T3	6.6 (1.6, 12.8)	0.02	7.8 (-0.2, 15.8)	0.054
TSH^†	40.3 (11.4, 77.1)	0.006	25.1 (-11.2, 77.6)	0.19

* Adjusted for age, BMI, and time of sample collection. Models for semen quality and sperm motion parameters additionally adjusted for abstinence period. ^†Variable ln-transformed in statistical analysis. ^‡Models for testosterone also adjusted for ln-transformed SHBG.