Independent variables used in regression models.

Table 2: Independent variables used in regression models.

			Models fitted for
Hg variable of interest	Independent variable	Type	Male: Iodine deficient	Male: Iodine replete	Female: Iodine deficient	Female: Iodine replete
Blood lead	Race/ethnicity	Categorical	X	X	X	X
	Age	Categorical	X	X	X	X
	Smoking status	Categorical	X	X	X	X
	Use of drugs other than thyroid treatment drugs	Indicator	X	X	X	X
	Poverty income ratio	Continuous	X	X	X	X
	Log10 of Body Mass Index	Continuous	X	X	X	X
	Log10 of Blood Lead	Continuous	X	X	X	X
	Log10 of Serum Albumin	Continuous	X	X	X	X
	NHANES** survey year	Ordinal	X	X	X	X
	Number of live births	Continuous			X	X
Menopause	Indicator				X	X
	Premenarche	Indicator			X	X
	Hormone use	Indicator			X	X
Urine lead	Race/ethnicity	Categorical	X	X	X	X
	Age	Categorical	X	X	X	X
	Smoking status	Categorical	X	X	X	X
	Use of drugs other than thyroid treatment drugs	Indicator	X	X	X	X
	Poverty income ratio	Continuous	X	X	X	X
	Log10 of Body Mass Index	Continuous	X	X	X	X
	Log10 of UIHG***	Continuous	X	X	X	X
	Log10 of Serum Albumin	Continuous	X	X	X	X
	NHANES** survey year	Ordinal	X	X	X	X
	Number of live births	Continuous			X	X
	Menopause	Indicator			X	X
	Premenarche	Indicator			X	X
	Hormone use	Indicator			X	X
	Log10 of Urine Creatinine	Continuous	X	X	X	X

**National Health and Nutrition Examination Survey; Independent variables used in the models are shown with an X.