Table 2.

Subgroup analysis to assess the association between serum levels of vitamin D and thyroid disorders

Sub-grouped by	No. of studies	Effect size1	95% CI	I2 (%)	P for heterogeneity	P for between subgroup heterogeneity
Hashimato
Age						<0.001
Adult	9	−5.69	−8.20, −3.18	89.6	<0.001
Adolescent	3	−6.81	−11.70, −1.93	87.8	<0.001
Geographical population						0.05
Turkey	6	−6.95	−11.15, −2.75	91.2	<0.001
Other countries	6	−5.35	−9.13, −1.58	92	<0.001
Hypothyroid
Gender						0.057
Both sex	8	−15.43	−29.49, −1.37	99.6	<0.001
Female	1	2.60	−1.38, 6.58	–	–
Geographical population						<0.001
Asian	4	−12.34	−31.89, 7.20	99.3	<0.001
Non-Asian	5	−14.31	−26.53, − 2.10	98.6	<0.001
Grave disease
Geographical population						<0.001
Asian	6	−1.74	−3.95, 0.46	80.2	<0.001
Non-Asian	2	−7.10	−18.47, 4.25	99.3	<0.001
Participants age						<0.001
≥ 40 years old	4	−8.79	−15.87, −1.72	98.1	<0.001
< 40 years old	4	−0.54	−2.07, 0.98	54.3	0.08
AITD
Geographical population						<0.001
Asian	6	−2.08	−5.6, 1.43	100	<0.001
Non-Asian	7	−4.13	−8.31, 0.05	93.9	<0.001
Study design						<0.001
Case control	7	−3.65	−7.75, 0.44	94.4	<0.001
Cross-sectional	6	−2.52	−6.10, 1.04	100	<0.001
Participants health status						<0.001
With metabolic disorders	5	−3.48	− 6.72, −0.24	85.9	<0.001
Without metabolic disorders	8	−2.87	−5.97, 0.23	99.9	<0.001

¹Calculated by Random-effects model