TABLE 2.

Multiple linear regression analyses of age, gender, and height-adjusted forced vital capacity (FVC) residuals, forced expiratory volume in one second (FEV1) residuals, and FEV₁/FVC ratio means by various socio-demographic categories

		FVC residual (ml)			FEV1 residual (ml)			FEV1/FVC
	N	Mean	95% CIa	pb	Mean res.	95% CIa	pb	Mean	95% CIa	pb
BMI (kg/m2)
18.5–<25	178	21	−63, 104	Ref	18	−55, 90	Ref	0.78	0.77, 0.79	Ref
25–30.0	375	12	−48, 73	0.88	13	−38, 63	0.91	0.79	0.79, 0.80	0.01
>30	198	−56	−136, 25	0.20	−47	−117, 24	0.21	0.80	0.79, 0.81	0.01
As exposure (µg/L)c
<11	198	39	−35, 113	Ref	−9	−68, 51	Ref	0.78	0.77, 0.79	Ref
11–200	202	−59	−137, 19	0.07	−27	−95, 41	0.69	0.80	0.79, 0.80	0.004
≥200	351	3	−63, 69	0.48	17	−40, 74	0.54	0.79	0.79, 80	0.005
Smokingd
Never	378	7	−53, 68	Ref	−8	−60, 44	Ref	0.79	0.78, 0.80	Ref
Light	124	1	−99, 101	0.92	18	−66, 103	0.60	0.79	0.78, 0.80	0.94
Moderate	122	−59	−156, 39	0.26	−21	−102, 60	0.79	0.79	0.78, 0.80	0.58
Heavy	128	16	−91, 122	0.89	16	−74, 107	0.64	0.79	0.78, 0.80	0.73
Ethnicity
Hispanic	636	−14	−60, 33	Ref	−1	−41, 39	Ref	0.79	0.79, 0.80	Ref
Aymara	85	70	−37, 178	0.16	14	−74, 102	0.59	0.78	0.77, 0.79	0.15
Other	30	55	−123, 233	0.45	26	−124, 177	0.60	0.80	0.78, 0.82	0.60
Education
College	224	64	−190, 146	Ref	39	−34, 111	Ref	0.79	0.78, 79	Ref
Some college	316	−58	−119, 2	0.02	−38	−89, 142	0.09	0.79	0.79, 0.80	0.18
High school	208	10	−70, 90	0.36	10	−55, 75	0.57	0.79	0.78, 0.80	0.49
SES scoree
High	543	−9	−59, 41	Ref	−12	−55, 31	Ref	0.79	0.79, 0.80	Ref
Low	208	11	−64, 87	0.65	24	−39, 87	0.35	0.79	0.78, 0.80	0.86
Occupational exposuref
No	564	10	−37, 57	Ref	7	−33, 47	Ref	0.79	0.79, 0.80	Ref
Yes	187	−47	−139, 44	0.27	−32	−109, 46	0.38	0.79	0.78, 0.79	0.38

Abbreviations: BMI, body mass index; CI, confidence interval; Ref, reference group; res, residual; SES, socioeconomic status

^a95% CIs are for the mean FEV1 or FVC residual for this category

^bP-value for the difference between the mean FEV1 or FVC residual in the corresponding category and the reference category

^cSingle year lifetime highest arsenic water concentration

^dLight, moderate, and heavy refer to ≤2.4, >2.4 to <8.5, and ≥8.5 pack years. Never smokers used as the reference group

^eHigh, upper two tertiles; Low, lower two tertiles

^fIncludes mining work and exposure to silica, asbestos, wood dust, arsenic, and fiberglass