Table 4.

Vitamin D related behaviors stratified by case and control groups

Variables	Cases (n = 130)		Controls (n = 195)		P-value*
	N	%	N	%
Sun exposure and using of sun protection
Do you work mainly:
Indoor	106	81.5	191	97.9	.001
Outdoor	24	18.5	4	2.1
How much time do you often spend outdoors per day on weekdays?
Not at all	23	17.7	20	10.3	.001
˂30 min	58	44.6	126	64.6
30–60 min	27	20.8	45	23.1
> 60 min	22	16.9	4	2.1
How much time do you often spend outdoors per days on weekends?
Not at all	46	35.4	95	48.7	.001
˂30 min	48	36.9	46	23.6
30–60 min	19	14.6	47	24.1
> 60 min	17	13.1	7	3.6
Which parts of your body get exposed to the sun?
Face	0	0	0	0	.001
Hand	12	9.2	29	14.9
Face & hand	95	73.1	156	80
Both arms	23	17.7	10	5.1
Both legs	0	0	0	0
Completely covered	0	0	0	0
How often do you wear sunscreen while outdoors in the sun?
Never	129	99.2	156	80	.001
1–4 times/week	0	0	23	11.8
> 5 times/week	1	0.8	16	8.2
The use of supplementation
Do you take vitamin D supplements
Yes	18	13.8	21	10.8	.403
No	122	86.2	174	89.2
Do you take calcium supplements?
Yes	4	3.1	9	4.6	.488
No	126	96.9	186	95.4
Do you take multivitamin supplements?
Yes	1	0.8	13	6.7	.010
No	129	99.2	182	93.3
Do you take calcium supplements with vitamin D?
Yes	1	0.8	5	2.6	.239
No	129	99.2	190	97.4
The intake of food rich in vitamin D
How often do you drink milk?
Never	33	25.4	82	42.1	.002
1–2 times/week	27	20.8	43	22.1
3–6 times/week	27	20.8	37	19
≥ once/day	43	33.1	33	16.9
How often do you eat butter?
Never	113	86.9	132	67.7	.001
1–2 times/week	12	9.2	40	20.5
3–6 times/week	4	3.1	20	10.3
≥ once/day	1	0.8	3	1.5
How often do you eat eggs?
Never	21	16.2	32	16.4	.998
1–2 times/week	95	73.1	142	72.8
3–6 times/week	14	10.8	21	10.8
≥ once/day	0	0	0	0
How often do you eat oily fish (salmon, tuna, sardine)?
Never	66	50.8	72	36.9	.034
1–2 times/week	44	33.8	73	37.4
3–6 times/week	14	10.8	41	21
≥ once/day	6	4.6	9	4.6
How often do you eat liver?
Never	106	81.5	125	64.1	.001
1–2 times/week	15	11.5	52	26.7
3–6 times/week	7	5.4	18	9.2
≥ once/day	2	1.5	0	0

*P-value based on X² -test