Table 2

The crude and multivariable-adjusted associations between 25(OH)D and baseline FEV₁/FVC<LLN,* NHANES, 2007–2010

Vitamin D measurements		Crude model†			A priori model‡
Vitamin D measurements		OR	95% CI	P value	OR	95% CI	P value
25(OH)D per 25 nmol/L§		1.06	0.96 to 1.16	0.24	0.96	0.86 to 1.07	0.46
Stratified by race/ethnicity
25(OH)D per 25 nmol/L§	Mexican American	1.19	0.90 to 1.58	0.21	0.89	0.68 to 1.16	0.36
	Other Hispanic	1.46	1.05 to 2.02	0.03	1.40	0.98 to 1.99	0.06
	Non-Hispanic White (Ref.)	0.98	0.88 to 1.10	0.77	0.94	0.84 to 1.06	0.29
	Non-Hispanic Black	0.88	0.70 to 1.10	0.24	0.80	0.61 to 1.05	0.10
	Other race, including multiracial	1.33	0.91 to 1.96	0.14	1.31	0.71 to 2.45	0.38
Total 25(OH)D, nmol/L¶
<30 (deficiency)		0.88	0.57 to 1.36	0.55	0.89	0.53 to 1.50	0.65
30–74 (insufficient=Ref.)		–	–	–	–	–	–
≥75 (sufficient)		0.96	0.77 to 1.19	0.69	0.77	0.61 to 0.98	0.04

*Lower limit of normal.
†Crude model included only vitamin D measurement only in the model.
‡Final model (a priori model) included the following covariates: vitamin D, age, gender, race/ethnicity, BMI, smoking, Season and income-to-poverty ratio.
§Total vitamin D as continues variables, total vitamin D=total vitamin D/25, 1 unit change equal to a change by 25 nmol/L of vitamin D.
¶Total vitamin D as a categorical variable.
BMI, body mass index; FEV₁, forced expiratory volume in 1 s; FVC, forced vital capacity; LLN, lower limit of normal; NHANES, National Health and Nutrition Examination Survey; 25(OH)D, 25-hydroxyvitamin D.