Table 4.

Multiple log-binomial regression models of oocyte fertilization in vitro on concentrations of metals measured in female patients and their male partners, with generalized estimating equations used to generate robust standard errors; the Study of Metals and Assisted Reproductive Technology (SMART).

Predictor Variables			95% CI			95% CI
	n a	RR b	Low	High	RR c	Low	High
Patients
Blood mercury (μg/L)	50	1.01	0.96	1.06	0.99	0.93	1.07
Urine cadmium (μg/L) d	55	1.27	0.83	1.95	1.41	0.62	3.17
Blood lead (μg/dL)	27	0.97	0.66	1.43	1.09	0.72	1.65
Partners
Blood mercury (μg/L)	33	0.97	0.92	1.03	0.97	0.91	1.03
Urine cadmium (μg/L) d	36	0.88	0.47	1.64	0.19 *	0.03	1.35
Blood lead (μg/dL)	16	1.13 **	1.01	1.27	1.08	0.97	1.21

^aSample size varies for single metal models due to missing values for metals concentrations;

^bRelative risk (RR) for a zygote as a function of concentrations of a single measured metal adjusted for age, cigarette smoking, race/ethnicity and urine creatinine (mg/dL) for cadmium;

^cn = 25 patients, n = 15 partners, relative risk for a zygote as a function of concentrations of all measured metals adjusted for age, cigarette smoking, race/ethnicity and urine creatinine (mg/dL);

^*P ≤ 0.10;

^**P ≤ 0.05.

CI, confidence interval