Table 2.

The serum level of vitamin D and percentage of vitamin D deficiency distribution among children with asthma in Asia and Africa

First Author/year	Country	Continent	Study Design	Sample size	Mean value of vitamin D	Vitamin D deficiency (%)	Quality status
Nabih et al. (2014) [38]	Egypt	Africa	Case–control	180	26 ± 12.5	77.3	Low risk
Kuti et al. (2021) [48]	Nigera	Africa	Case–control	90	38 ± 17	26	Low risk
Ibegbu et al. (2022) [27]	Nigera	Africa	Cross sectional	65	68.6 ± 25.9	1.5	High risk
Elnadya et al. (2013) [40]	Egypt	Africa	Cross sectional	50	24.1 ± 2.9	40	Low risk
Omole et al. (2018) [49]	Nigera	Africa	Cross sectional	103	49.2 ± 7.2	2	High risk
Gamal et al. (2018) [39]	Egypt	Africa	Cross sectional	90	12.2 ± 1.9	80	Low risk
El-Menem et al. (2013) [41]	Egypt	Africa	Case–control	60	39 ± 12	45	Low risk
Ahmed et al. (2020) [37]	Egypt	Africa	Case–control	36	7.69 ± 2.3	75	Low risk
Kim (2017) [58]	S/Korea	Asia	Cross sectional	50	16.3 ± 4.2	86	Low risk
Mohammad et al. (2020) [50]	Iran	Asia	Cross sectional	200	20.4 ± 13.4	36.5	Low risk
Ahmed et al.  (2020) [37]	Egypt	Africa	Case–control	50	13.5 ± 10.5	72	Low risk
KAVITHA et al. (2017) [26]	India	Asia	Cross sectional	105	9 ± 5.1	66.7	Low risk
Maalmi (2013) [59]	Tunisia	Africa	Case–control	155	18.9 ± 6.7	61.3	Low risk
Zhang et al. (2017) [53]	China	Asia	Case–control	143	22.2 ± 10.5	48.9	Low risk
Dabbah et al. (2015) [60]	Israel	Asia	Cross sectional	71	23 ± 7.7	36.6	Low risk
Uysalol et al. (2013) [25]	Turkey	Asia	Cross sectional	85	16.6 ± 8.5	29.4	Low risk
Anand et al. (2021) [56]	India	Asia	Case–control	101	17.3 ± 12.2	64.4	Low risk
Dogru (2014) [42]	Turkey	Asia	Case–control	120	21.5 ± 7.7	43.3	Low risk
Kang et al. (2018) [54]	China	Asia	Case–control	96	18.9 ± 3.6	Not found	Low risk
Hou et al. (2018) [55]	China	Asia	Case–control	70	16.8 ± 3.3	Not found	Low risk
Yusuff et al. (2022) [47]	Nigera	Africa	Cross sectional	128	22.4 ± 2.9	Not found	Low risk
Al-Sharifi et al. (2017) [61]	Iraq	Asia	Cross sectional	50	2.05 ± 0.4	Not found	Low risk
Bai and Dai (2018) [21]	China	Asia	Case–control	57	17.5 ± 2.1	Not found	Low risk
Thomas et al. (2019) [45]	Turkey	Asia	Cross sectional	73	12.1 ± 7.4	82.2	Low risk
Havan et al. (2017) [44]	Turkey	Asia	Cross sectional	72	14.2 ± 6.7	80.6	Low risk
Hatami et al. (2014) [51]	Iran	Asia	Case–control	200	20.3 ± 2.8	56	Low risk
Awasthi (2014) [57]	India	Asia	Case–control	50	20.8 ± 8.1	57.1	Low risk
Krobtrakul et al. (2013) [62]	Thailand	Asia	Cross sectional	125	25.9 ± 9.4	19.2	Low risk
Alyasin et al. (2011) [52]	Iran	Asia	Cross sectional	50	49.3 ± 21.4	4	High risk
Kilic et al. (2019) [43]	Turkey	Asia	Case–control	100	22.2 ± 12.3	58.4	Low risk
Esfandiar et al. (2016) [20]	Iran	Asia	Case–control	53	14.5 ± 8.1	73.6	Low risk
Bener et al. (2012) [63]	Qatar	Asia	Case–control	483	17.2 ± 11.1	68.1	Low risk
Ozdogan et al. (2017) [46]	Turkey	Asia	Cross sectional	71	11.8 ± 10.3	4	High risk