1,25(OH)2D	1,25-dihydroxyvitamin D
25(OH)D	25-hydroxyvitamin D
ANA	Anti-nuclear antibodies
AITD	Autoimmune thyroid disease
GD	Graves’ disease
HLA	Human leukocyte antigen
HPA	Hypothalamic–pituitary–adrenal
IU	International Units
IBD	Inflammatory bowel disease
JIA	Juvenile idiopathic arthritis
MS	Multiple sclerosis
MIS-C	Multi-system inflammatory syndrome in children
RCTs	Randomized controlled trials
RF	Rheumatoid factor
SLE	Systemic lupus erythematosus
SR	Systematic reviews
T1DM	Type 1 Diabetes Mellitus
TLR	Toll-like receptor
TPoA	Thyroperoxidase antibodies
UVB	Ultraviolet-B
VDR/CTR	Vitamin D (calcitriol) receptor