Table 4. Hazard ratios and 95% confidence intervals for the prospective associations between serum 25-OH vitamin D status and incident fatal and non-fatal COPD (person years at risk = 101,719, number of events = 375, total number = 10,523).

Fatal and non-fatal COPD¤	Model 1$ HR (95% CI)	Model 2& HR (95% CI)	Model 3% HR (95% CI)	Model 4€ HR (95% CI)
per 10 nmol/l higher 25-OH-D	0.91 (0.87, 0.95)	0.91 (0.87, 0.95)	0.94 (0.90,0.98)	0.98 (0.94, 1.0)
	P<0.0001	P<0.0001	P = 0.008	P = 0.376
1st vitamin D quartile	1 (reference)	1 (reference)	1 (reference)	1 (reference)
2nd vitamin D quartile	0.57 (0.43, 0.75)	0.57 (0.43, 0.75)	0.64 (0.48, 0.85)	0.73 (0.55, 0.97)
3rd vitamin D quartile	0.65 (0.49, 0.84)	0.64 (0.49, 0.84)	0.83 (0.63, 1.1)	1.0 (0.77, 1.4)
4th vitamin D quartile	0.49 (0.37, 0.66)	0.48 (0.36, 0.65)	0.61 (0.44, 0.83)	0.75 (0.55, 1.0)
	Ptrend<0.0001	Ptrend<0.0001	Ptrend = 0.009	Ptrend = 0.285

^$Adjusted for study population.

^&Further adjusted for gender, education, and season.

^%Further adjusted for alcohol consumption, smoking, leisure time physical activity, intake of fish, and BMI.

^€Further adjusted for baseline FEV1% predicted.

^¤Persons with a diagnosis of COPD before baseline were excluded. Complete case analysis.

Abbreviations: CI, confidence interval; COPD, chronic obstructive pulmonary disease; BMI, body mass index; HR, hazard ratio; 25-OH-D, 25-hydroxyvitamin D; FEV1% predicted, forced expiratory volume in one second in % of predicted.