Table 3.

The Association Between Respiratory Symptoms and Vitamin D Level < 30ng/mL

	Unadjusted		Adjusted*
	OR (95% CI)	P-value	OR (95% CI)	P-value
Total CAT score ≥ 10
Vitamin D ≥ 30 ng/mL (N = 48)	Reference
Vitamin D < 30 ng/mL (N= 281)	2.34 (1.17–4.68)	0.016	2.41 (1.20–4.82)	0.013
mMRC ≥ 2
Vitamin D ≥ 30 ng/mL (N = 48)	Reference
Vitamin D < 30 ng/mL (N= 281)	2.01 (0.98–4.10)	0.056	2.39 (1.08–5.32)	0.032

Notes: *Adjusted for age, sex, body mass index and smoking history (never vs ever), Charlson comorbidity index, post bronchodilator FEV₁ (≥ 50% vs < 50% pred), and season of blood draw (spring/fall vs summer vs winter).

Abbreviations: OR, odds ratio; CI, confidence interval; CAT, COPD assessment test; mMRC, modified Medical Research Council.