Abdollahi et al. [27] |
402 |
402 |
– |
– |
I |
I |
I(+) |
VDD was defined as <10 ng/mL, but the sample distribution for VDD was not suitable for statistical analysis; A statistical comparison was made for VDIS <30 ng/mL; Therefore, the data belonging to VDIS were included in the meta-analysis, and the measurement unit was assigned as “other” |
Baktash et al. [28] |
105 |
– |
– |
70 |
I-M |
M |
I(+); M(-) |
There was uncertainty in the definition of comparison groups for COVID-19 infection; We sent an email to the corresponding author, but we did not receive a reply; Therefore, COVID-19 infection data were not included in the D-CIMA |
Campi et al. [29] |
361 |
361 |
103 |
103 |
I-S-M |
I-S-M |
I(+); S(+); M(+) |
There was no limitation in data extraction |
Cereda et al. [30] |
129 |
– |
129 |
129 |
S-M |
S-M |
S(+); M(+) |
The clinical outcomes were severe pneumonia, admission to the ICU, and in-hospital mortality; The ICU admission data were not appropriate for statistical analysis (0 observed cases); Therefore, we extracted data from severe pneumonia for the analysis of severity |
D’Avolio et al. [21] |
1,484 |
– |
– |
– |
I |
– |
I(+) |
The definition of VDD was not available; There was no adequate information dealing with descriptive statistics; VDD was presented as median (IQR) and the findings were presented graphically; Since we extracted the data based on the number of cases, we did not include it in the meta-analysis In the study, the date of the data received from UK Biobank for the COVID-19 (-) control group was long ago; There was no VDD definition and they used quartile values of VDD; Since we extracted the data based on the number of cases, we did not include it in the meta-analysis |
Darling et al. [22] |
1,303 |
– |
– |
– |
I |
– |
I(-) |
In the study, the date of the data received from UK Biobank for the COVID-19 (-) control group was long ago; There was no VDD definition and they used quartile values of VDD; Since we extracted the data based on the number of cases, we did not include it in the meta-analysis |
De Smet et al. [31] |
2,903 |
2,903 |
186 |
– |
I-S |
I-S |
I(+); S(+) |
In the study, chest CT was performed for all COVID-19 patients to determine the disease stage; They classified the patients as stage 1 (early stage), stage 2 (progressive stage), and stage 3 (peak stage); We chose severe cases from stage 3 and non-severe cases from stage 1-2 |
Hastie et al. [23] |
341,484 |
– |
– |
– |
I-M |
– |
I(-); M(-) |
There was no adequate information dealing with descriptive statistics; The findings were presented by using HR and IRR values; Since we extracted the data based on the number of cases, we did not include it in the meta-analysis |
Hernández et al. [32] |
413 |
– |
197 |
197 |
I-S-M |
S-M |
I(+); S(-); M(-) |
For COVID-19 infection, VDD was presented as mean (±SD); Since the number of cases was not reported, we could not include it in D-CIMA |
Im et al. [24] |
200 |
– |
– |
– |
I-S |
– |
I(+); S(+) |
In the study, the unit of ng/dL was used for laboratory measurements of serum 25(OH)D levels, and VDD was defined as 25(OH)D<20 ng/dL; We converted 20 ng/dL to 0.2 ng/mL; Since we thought there was an inconsistency, we could not include these data in the meta analyses |
Israel et al. [33] |
576,455 |
187,234 |
– |
– |
I |
I |
I(+) |
Age matching was performed between the case and control groups, but single summary statistics for the population were not presented |
Karahan and Katkat [34] |
149 |
– |
149 |
149 |
S-M |
S-M |
S(+); M(+) |
There was no limitation in data extraction |
Katz et al. [25] |
987,849 |
– |
– |
– |
I |
– |
I(+) |
There was no adequate information dealing with descriptive statistics; The findings were presented as ORs; Since we extracted the data based on the number of cases, we did not include it in the meta-analysis |
Li et al. [35] |
353,299 |
3,502 |
1,082 |
– |
I-H-S |
I-S |
I(+); H(+); S(+) |
This study defined hospitalization as one record of origin (whether the patient s tested positive or not); In the study, hospitalized, confirmed, and severe COVID-19 cases were compared with community controls; We think that this study design is inappropriate; For this reason, we extracted data on infections from patients who presented to the hospital with suspected COVID-19 and confirmed COVID-19, and for the severity from patients with confirmed and severe COVID-19 |
Livingston et al. [36] |
104 |
104 |
– |
– |
I |
I |
I(-) |
The definition of VDD was not available; Statistical comparisons were performed for 25(OH)D <34.4 nmol/L; Therefore, the data belonging to this distinction were included in the meta-analysis, and the measurement unit was assigned as “other” |
Luo et al. [37] |
895 |
895 |
335 |
74 |
I-S-M |
I-S-M |
I(+); S(+); M(-) |
There was no limitation in data extraction |
Macaya et al. [38] |
80 |
– |
80 |
|
S |
S |
S(+) |
There was no limitation in data extraction |
Maghbooli et al. [39] |
235 |
– |
235 |
235 |
H-S-M |
S-M |
H(+); S(+); M(+) |
There was no limitation in data extraction; Although the authors defined VDD as 25(OH)D<20 ng/mL, the dataset that could be extracted from the article belonged to the category of 25(OH)D<30 ng/mL; Therefore, it was included in the overall analysis |
Mardani et al. [40] |
123 |
123 |
– |
– |
I |
I |
I(+) |
We extracted data from their supplementary file according to 25(OH)D<20 ng/mL |
Meltzer et al. [41] |
489 |
489 |
– |
– |
I |
I |
I(+) |
There was no limitation in data extraction |
Mendy et al. [42] |
689 |
– |
689 |
– |
H-S |
S |
H(+); S(+) |
The definition of VDD was not available; Therefore, the measurement unit was assigned as “other” in the D-CSMA |
Merzon et al. [43] |
7,807 |
7,807 |
– |
– |
I-H |
I |
I(+); H(+) |
There was no limitation in data extraction |
Panagiotou et al. [44] |
134 |
– |
134 |
– |
S |
S |
S(+) |
The authors classified the patients as admitted to the ITU and non-ITU wards; |
When we extracted data, we chose patients admitted to non-ITU wards as non-severe and those admitted to ITU wards as severe; A statistical comparison was made for VDIS <50 nmol/L; Therefore, the data belong to VDIS were included in the D-CSMA |
Radujkovic et al. [45] |
185 |
– |
185 |
– |
S-M |
S |
S(+); M(+) |
The authors classified patients as inpatients and outpatients; When we extracted data, we chose the outpatients as non-severe and the inpatients as severe according to their definition |
Vassiliou et al. [46] |
39 |
– |
– |
39 |
H-M |
M |
H(-); M(-) |
There was no limitation in data extraction |
Ye et al. [47] |
142 |
142 |
60 |
– |
I-S |
I-S |
I(+); S(+) |
There was no limitation in data extraction |
Total |
2,277,860 |
203,962 |
3,564 |
996 |
|
|
|
|