Table 2.

Selected traits of study population and mean FEV₁/FVC

Trait	Number (%)	Mean FEV1/FVC	p < 0.001
All	177,721 (100)	0.779	—
Sex
Women	96,223 (54.1)	0.787	Versus men
Men	81,498 (45.9)	0.771	Versus women
Age (years)
<40	83,485 (47.0)	0.794	Versus each other bracket
40–49	36,871 (20.8)	0.783	Versus each other bracket
50–59	32,001 (18.0)	0.775	Versus each other bracket
60–69	18,864 (10.5)	0.760	Versus each other bracket
>70	6,500 (3.7)	0.745	Versus each other bracket
Ethnicity
White	136,997 (77.1)	0.768	Versus each other ethnicity
African American	26,409 (14.9)	0.786	Versus white, other
Asian American	7,248 (4.1)	0.783	Versus white
Other	7,067 (4.0)	0.779	Versus white, African American
Smoking history
Never	67,608 (38.0)	0.790	Versus each, except unknown
Ex-smoker	30,338 (17.1)	0.782	Versus each, except unknown
<1 ppd	37,875 (21.3)	0.775	Versus each, except unknown
≥1 ppd	37,623 (21.2)	0.763	Versus each, except unknown
Unknown	4,277 (2.4)	0.786	Versus <1 ppd; ≥1 ppd
Alcohol in past year—drinks per day
None	38,074 (21.4)	0.779	Versus each other, except ≥6
≤2	107,827 (60.7)	0.787	Versus each other, except 3–5
3–5	14,265 (8.0)	0.783	Versus each other, except ≥6
≥6	4,084 (2.3)	0.773	Versus 3–5, ≥2
Unknowna	13,471 (7.6)	0.772	Versus each other, except ≥6
Body mass index (kg/m2)
<25	88,146 (49.6)	0.774	Versus each other
25–29	50,599 (28.5)	0.783	Versus each other
≥30	15,321 (6.6)	0.790	Versus each other
Unknown	23,655 (13.3)	0.769	Versus each other
Education
No college	86,712 (48.8)	0.773	Versus each, except unknown
Some college	49,770 (28.0)	0.780	Versus each other
College graduate	36,243 (20.3)	0.786	Versus each other
Unknownb	4,996 (2.8)	0.769	Versus each, except no college
Possible baseline cardiorespiratory illnessc
Yes	108,400 (61.0)	0.770	Versus no
No	69,321 (39.0)	0.789	Versus yes

^a Analysis of variance; covariates were age, sex, ethnicity, body mass index, education, smoking, alcohol, and baseline illness composite.

^b Nonresponse or conflicting response.

^c Any of 47 medical history or symptom items “yes.”

FEV₁ = one-second forced expiratory volume; FVC = forced vital capacity; FEV₁/FVC = ratio of FEV₁ to FVC; ppd = pack(s) per day.