Table 4

Relationship between total vitamin D intake and FEV₁ (n=2942) and FVC, FEV₁/FVC and COPD (n=2936)

	FEV₁			FEV₁/FVC
	Regression coefficient (l)^*	95% CI	p Value	Regression coefficient^*	95% CI	p Value
Fifths of vitamin D intake:
1 (lowest)	–	–	–	–	–	–
2	−0.008	(−0.061 to 0.045)	0.770	0.001	(−0.009 to 0.010)	0.897
3	0.001	(−0.053 to 0.056)	0.963	0.005	(−0.005 to 0.014)	0.307
4	0.042	(−0.015 to 0.099)	0.147	0.007	(−0.003 to 0.017)	0.157
5 (highest)	0.079	(0.017 to 0.141)	0.012	0.014	(0.003 to 0.025)	0.010

Effect per quintile increase in vitamin D intake	0.020	(0.006 to 0.034)	0.007	0.003	(0.001 to 0.006)	0.008

	FVC			COPD
	Regression coefficient (l)^*	95% CI	p Value	OR^*	95% CI	p Value
Fifths of vitamin D intake:
1 (lowest)	–	–	–	–	–	–
2	−0.003	(−0.065 to 0.060)	0.931	0.903	(0.644 to 1.266)	0.553
3	−0.015	(−0.078 to 0.049)	0.644	0.913	(0.650 to 1.281)	0.597
4	0.031	(−0.036 to 0.098)	0.360	0.827	(0.572 to 1.197)	0.314
5 (highest)	0.056	(−0.016 to 0.128)	0.128	0.570	(0.375 to 0.866)	0.008

Effect per quintile increase in vitamin D intake	0.014	(−0.003 to 0.031)	0.109	0.894	(0.814 to 0.983)	0.020

↵* Adjusted for energy intake, smoke in home, smoker status, pack years, age left education, home ownership status, no. of rooms, no. of cars, social class, fat mass, activity score, alcohol, dietary supplement use, birth weight, father's social class at birth, inhaled or oral steroids use and paracetamol use. Age, height and gender were also included in the COPD analyses.
COPD, chronic obstructive pulmonary disease; FEV₁, forced expiratory volume in 1 s; FVC, forced vital capacity; 25(OH)D, 25 hydroxy vitamin D.