. 2020 Dec 21;16(Suppl 3):e13065. doi: 10.1111/mcn.13065

TABLE 3.

Blood haemoglobin, plasma ferritin, folic acid and vitamin B₁₂ status among different age groups

Biomarker	6–9 years (n = 54)	10–13 years (n = 174)	14–17 years (n = 72)	Pooled (N = 300)	P value
Blood haemoglobin, g dL⁻¹	11.16 ± 1.24^a	11.68 ± 1.24^b	11.61 ± 1.64^ab	11.57 ± 1.36	0.047 ^*
Blood haemoglobin, g dL⁻¹	11.37^a (10.37, 12.04)	11.77^b (11.19, 12.54)	11.63^ab (10.64, 12.78)	11.66 (10.83, 12.51)	0.027 ^*
Plasma ferritin, μg L^−1†	20.26 ± 14.32^a	17.05 ± 13.4^a	14.43 ± 10.99^a	16.99 ± 13.12	0.051
Plasma ferritin, μg L^−1†	15.62^a (9.60, 28.05)	12.17^ab (7.90, 22.31)	9.16^b (5.65, 19.8)	12.20 (7.62, 23.18)	0.023 ^*
Plasma folic acid, nmol L⁻¹	16.70 ± 5.95^a	14.21 ± 8.28^b	11.12 ± 3.56^c	13.81 ± 7.24	<0.001 ^***
Plasma folic acid, nmol L⁻¹	15.86^a (11.17, 21.11)	12.67^b (10.20, 16.10)	11.06^c (8.42, 13.14)	12.46 (9.90, 16.09)	<0.001 ^***
Plasma vitamin B₁₂, pmol L⁻¹	191.48 ± 121.62^a	188.57 ± 98.75^a	111.26 ± 80.44^b	169.91 ± 103.73	<0.001 ^***
Plasma vitamin B₁₂, pmol L⁻¹	158.76^a (100.84, 291.7)	165.84^a (118.7, 244.08)	91.72^b (42.45, 159.48)	149.83 (98.84, 229.09)	<0.001 ^***

Note: Values are mean ± SD and median (IQR); IQR, (P₂₅, P₇₅); P₂₅, 25th percentile; P₇₅, 75th percentile. Mean values between age groups were compared by one‐way ANOVA with post‐hoc LSD test. Median values between age groups were compared using Kruskal–Wallis test. Significant differences in values between age groups are indicated by different superscript letters a, b and c.

^†Plasma ferritin values of seven children, that is, two children (6–9 years), four children (10–13 years) and one child (14–17 years), were excluded from analysis as their C reactive protein concentration was > 5 mg L⁻¹.

Abbreviations: ANOVA, analysis of variance; IQR, inter quartile range; LSD, least significant disfference; SD, standard deviation.

^{^*}

Significantly different at P ≤ .05.

^{^***}

Significantly different at P≤ .001.