Table 2.

Plasma levels of 25-hydroxyvitamin D, as determined using an LC-MS assay, in adults and the proportions of participants with levels below 30 and 50 nmol/l

	n	Median P-25(OH)D (nmol/l)	Mean P-25(OH)D (nmol/l)	sd	Range	% (n) <30 nmol/l	% (n) <50 nmol/l
Women and men	268	62⋅8	63⋅5	18⋅2	20–168	3⋅4 (9)	22⋅4 (60)
Women	144	65⋅1	64⋅6	19⋅3	24–168	4⋅9 (7)	20⋅8 (30)
Men	124	60⋅3	62⋅2	16⋅8	20–105	1⋅6 (2)	24⋅2 (30)
P value			0⋅265			0⋅156a	0⋅511a
Age groups
18–30 years	44	66⋅3	65⋅7	24⋅4	20–168	6⋅8 (3)	18⋅2 (8)
31–44 years	62	63⋅0	62⋅3	15⋅3	30–95	0	22⋅6 (14)
45–64 years	96	61⋅6	62⋅2	18⋅8	24–105	5⋅2 (5)	28⋅1 (27)
65–80 years	66	63⋅7	65⋅0	14⋅7	33–101	0	16⋅7 (11)
P value			0⋅606			0⋅050a	0⋅319a
Season
Summerb	210	65⋅0	65⋅7	17⋅5	24–168	1⋅4 (3)	17⋅6 (37)
Winterc	58	55⋅0	55⋅4	18⋅3	20–94	8⋅6 (5)	39⋅7 (23)
P value			<0⋅0001			0⋅004a	<0⋅0001a

P-25(OH)D, plasma 25-hydroxyvitamin D.

^aDifferences in the proportions of 25(OH)D concentrations below 30 or 50 nmol/l.

^bSummer values are defined as values obtained from blood samples collected in May–October.

^cWinter values are defined as values obtained from blood samples collected in November–April.