TABLE 1.

Age-standardized characteristics of the study population in pre- and postfortification periods, according to quintiles of cumulative average total folate intake¹

	Prefortification (1980–1998)			Postfortification (1998–2016)
	Quintile 1	Quintile 3	Quintile 5	Quintile 1	Quintile 3	Quintile 5
Person-y	301,168	299,454	299,524	216,011	214,542	214,346
Age at baseline, y	45	47	47	63	63	64
BMI	25.1	25.1	24.6	26.2	25.8	25.5
Height, cm	164	164	164	163	164	164
Physical activity, MET h/wk	11.3	15.9	17.4	15.3	18.3	20.0
Smoker before age 30 y, %	57.4	50.6	51.7	52.0	50.6	50.6
Pack-y of smoking before age 30 y, among smokers	7.2	6.9	7.1	7.0	6.9	7.0
History of previous endoscopy, %	9.2	13.3	13.5	27.5	33.6	35.0
Family history of CRC, %	18.0	19.1	18.2	20.1	19.5	19.7
Multivitamin use, %	13.0	27.5	86.3	22.1	84.4	92.3
Folic acid supplement, %	2.2	3.4	7.9	5.8	12.3	33.9
Regular aspirin or other NSAID use, %	48.4	57.7	58.6	62.1	71.0	71.8
Postmenopausal, %	69.5	70.4	70.3	99.2	99.3	99.3
Current menopausal hormone use, %	22.9	32.8	36.5	23.7	23.3	24.7
Never drinker, %	28.9	24.1	25.0	21.2	17.2	18.8
Dietary intake
Total folate, DFE/d	189	377	1126	432	1073	1745
Dietary folate, DFE/d	190	332	329	422	481	593
Synthetic folic acid, DFE/d	13	101	1022	181	789	1430
Natural folate, DFE/d	179	273	269	254	278	316
Alcohol among drinkers, g/d	9.7	7.7	8.2	7.3	7.4	6.2
Total vitamin D, IU/d	184	257	629	188	202	219
Total calcium, mg/d	666	860	986	703	762	810
Dietary fiber, g/d	11	17	16	17	18	20
Unprocessed red meat, svg/d	0.8	0.7	0.6	0.6	0.6	0.4
Processed red meat, svg/d	0.4	0.3	0.3	0.3	0.3	0.2

¹All variables are standardized to the age distribution of the study population, except for age. Mean value is presented for continuous variables and percentage of participants for categorical variables. CRC, colorectal cancer; DFE: dietary folate equivalent; MET, metabolic equivalent of task; NSAID, nonsteroidal anti-inflammatory drug; svg: serving.