Fig. 2

25-hydroxyvitamin D concentration in breastfeeding women compared to NPNB women. Bars indicate mean ± standard deviation; Breastfeeding vs. non-breastfeeding women in total study sample: p <0.001^‡; Between season in breastfeeding women: p < 0.001^†; Between season in NPNB women: p = 0.002^†; Breastfeeding vs. NPNB women in spring: p = 0.391^‡, summer: p = 0.352^‡, autumn: p = 0.026^‡, winter: p = 0.001^‡; Autumn, September – November; NPNB, non-pregnant and non-breastfeeding; Spring, March – May; Summer, June – August; Winter, December – February; ^‡Mann-Whitney U-test, †Kruskal-Wallis-test