Table 5.

Association of demographic factors in children (N = 1,641) from NHANES 2011–2014 with urinary tin concentrations (creatinine was adjusted in the model).

Variables	Urinary tin concentrations
	β coefficient	P
Age
6–11	[ref]
12–19	−1.08	<0.0001
Gender
Male	[ref]
Female	0.09	0.30
Race/ethnicitya
Non-Hispanic white	[ref]
Hispanic	0.09	0.26
Non-Hispanic black	0.30	0.01
Other	0.08	0.65
Family income to poverty ratiob
≤1.30	[ref]
1.30–3.50	−0.20	0.047
>3.50	−0.42	< 0.0001
Missing	−0.32	0.01
BMI, kg/m2c
<25	[ref]
25–29.9	−0.07	0.31
≥30	−0.11	0.27
Missing	0.50	0.07

^aRace/ethnicity was categorized based on self-reported data into Hispanic (including Mexican and non-Mexican Hispanic), non-Hispanic white, non-Hispanic black and other race/ethnicity (Liu et al., 2017).

^bFamily income to poverty ratios were categorized as ≤ 1.30, 1.30–3.50, and > 3.50 (Johnson et al., 2013; Liu et al., 2017)

^cBMI was calculated as weight in kilograms divided by the square of height in meters and classified as normal weight, overweight, and obese based on the CDC’s sex-specific 2000 BMI-for-age growth charts for the U.S. Weight and height were determined by trained health technicians according to the NHANES Anthropometry Procedures Manual (WHO, n.d.-b).

CDC, Center for Disease Control and Prevention; BMI, body mass index.