Table 1.

Baseline participant characteristics, according to quartile of frequency of ultra-processed food intake, of adults aged ≥20 years (n 11898), Third National Health and Nutrition Examination Survey (NHANES III, 1988–1994)^*

	Quartile of frequency of ultra-processed food intake
	Quartile 1 (n 2982)		Quartile 2 (n 2989)		Quartile 3 (n 2985)		Quartile 4 (n 2942)
Characteristic	Mean	se	Mean	se	Mean	se	Mean	se	P value†
Ultra-processed food intake (times/d), range	0–<2·6		2·6–<3·8		3·8–<5·2		5·2–<29·8		<0·001
Age (years)	43	0·5	42	0·5	41	0·5	38	0·5	<0·001
Female sex(%)	59		52		51		45		<0·001
Race/ethnicity(%)
Non-Hispanic White	65		77		81		80		<0·001
Non-Hispanic Black	11		9		9		12
Mexican American	8		6		5		4
Other	16		8		5		4
Poverty level(%)
<130 %	20		16		15		18		<0·001
130–<350%	40		43		47		49
≥350%	40		40		38		33
Education level(%)
Less than high school	25		20		20		21		<0·001
High school	31		35		34		35
More than high school	44		45		46		44
Smoking status(%)
Current	28		28		28		34		0·01
Former	22		25		24		22
Never	50		47		47		44
Physical activity (MET/week)	29	5·5	24	1·0	25	0·9	27	0·9	0·08
Alcohol intake (drinks/month)	8	0·6	9	0·6	9	0·4	10	0·7	0·09
BMI (kg/m2)	26·2	0·1	26·3	0·1	26·1	0·2	26·2	0·2	0·95
Hypertension status(%)	26		25		26		24		0·71
Total cholesterol (mg/dl)	203	1·5	202	1·2	201	1·3	197	1·4	0·02
eGFR (ml/min per 1·73 m2)	101	0·5	102	0·6	102	0·6	105	0·5	<0·001

MET, metabolic equivalent of task; eGFR, estimated glomerular filtration rate.

^*Values presented are means and their se for continuous variables, and as percentages for categorical variables.

^†We tested for differences in baseline characteristics using weighted χ ² tests for categorical variables and weighted ANOVA for continuous variables.