Table 1.

Characteristics of the Study Population, by the Log-transformed %MEHP Quartile (% or Mean [SD]), NHANES 2001–2012

Characteristic	1^st quartile Sample N=1,317	2^nd quartile Sample N=1,318	3^rd quartile Sample N=1,318	4^th quartile Sample N= 1,318
Age, years^*	48.5 (0.7)	44.9 (0.6)	42.2 (0.5)	40.6 (0.6)
Race^*
Caucasian	76.8%	74.1%	68.7%	64.4%
Other Race	5.9%	6.5%	7.7%	9.9%
Mexican-American or other Hispanic	9.3%	12.4%	13.2%	14.2%
Non-Hispanic Black	8.0%	7.0%	10.4%	11.5%
Gender
Male	47.5%	49.8%	48.1%	49.2%
Female	52.5%	50.2%	51.9%	50.8%
BMI^†
Normal	44.7%	47.9%	51.2%	52.1%
Underweight	2.4%	3.2%	3.2%	3.1%
Overweight	52.9%	48.9%	45.5%	44.8%
Smoking^*
Never smoker	52.6%	51.6%	52.9%	53.7%
Past smoker	26.7%	20.6%	19.9%	16.3%
Current smoker	21.2%	27.8%	27.2%	30.0%
Alcohol use
None	14.7%	16.0%	14.5%	13.3%
Below limit	69.2%	69.4%	72.9%	74.6%
Above limit	16.0%	14.6%	12.6%	12.1%
Cancer history^*
No	88.0%	90.9%	93.6%	93.5%
Yes	12.0%	9.1%	6.4%	6.5%
Caffeine, g/day^* ^a
1^st Quartile	19.1%	14.9%	18.3%	23.5%
2^nd Quartile	21.0%	24.0%	23.8%	22.1%
3^rd Quartile	26.4%	29.1%	25.4%	25.2%
4^th Quartile	33.5%	32.0%	32.5%	29.3%
Prescription medication^*
Did not use in past month	40.4%	49.6%	53.5%	54.5%
Used in past month	59.6%	50.4%	46.5%	45.5%
Menopausal status/postmenopausal hormone use (women only)^*^b
Premenopausal	56.3%	60.3%	67.5%	73.1%
Postmenopausal/Never used	22.7%	18.7%	17.5%	14.1%
Postmenopausal/Past, not current	12.4%	13.7%	8.6%	8.8%
Postmenopausal, Past/unknown current	3.0%	3.5%	2.2%	0.3%
Postmenopausal/Current	5.5%	3.8%	4.2%	3.7%

differences across quartiles significant at 0.001 level

^†

differences across quartiles significant at 0.05 level

1^st − <10; 2^nd: 10−<91 ; 3^rd − 91−<208; and 4^th −>208 mg

N of women for each % quartile: 1st quartile: Sample N = 603, Weighted N =11,899,351; 2nd quartile: Sample N = 616, Weighted N = 12,182,219; 3rd quartile: Sample N = 633, Weighted N =12,507,047; 4th quartile: Sample N = 586 Weighted N =11,381,258