Breastfeeding woman are at higher risk of vitamin D deficiency than non-breastfeeding women - insights from the German VitaMinFemin study

Table 2 Univariate odds ratios for vitamin D deficiency (<25.0 nmol/L) in breastfeeding women

Determinants	N	Persons at risk (% of category)	P value	Odds ratios	95% CI	P value
Season
Summer and Autumn	77	15 (19.5)	0.021*	1.0	Ref.
Winter and Spring	47	18 (38.3)	0.021*	2.6	1.1, 5.8	0.023
Region^a
Latitude	/	/	/	1.1	0.9, 1.3	0.378
Longitude	/	/	/	0.7	0.6, 0.9	0.006
Skin type
Light	109	29 (26.6)	0.996*	1.0	Ref.
Dark	15	4 (26.7)	0.996*	1.0	0.3, 3.4	0.996
Recent holidays
Yes	5	1 (20.0)	0.733*	1.0	Ref.
No	119	32 (26.9)	0.733*	0.7	0.2, 13.7	0.734
Smoking
No	113	30 (26.5)	0.959*	1.0	Ref.
Yes	11	3 (27.3)	0.959*	1.0	0.3, 4.2	0.959
Age^a	/	/	/	0.9	0.9, 1.0	0.163
BMI^a	/	/	/	1.1	1.0, 1.2	0.045
Duration of breastfeeding (month)^b	/	/	/	1.0	1.0, 1.0	0.703
Stage of life
Breastfeeding women	124	16 (12.9)	0.007*	1.0	Ref.
NPNB women	124	33 (26.6)	0.007*	2.5	1.3, 4.7	0.008

25(OH)D, 25-hydroxyvitamin D; Autumn, September – November; BMI, body mass index; CI, confidence interval; NPNB, non-pregnant and non- breastfeeding; Ref., reference category with the lowest assumed prevalence of vitamin D deficiency; Spring, March – May; Summer, June – August; Winter, December – February
*Chi-square test for prevalence differences of 25(OH)D concentrations below 25 nmol/L
^aOdds ratio for an increase per one unit
^b n = 123

ISSN: 1746-4358