Table II.
Subgroup analysis based on the continent for relative risk (RR) in A) clinical hypothyroidism and B) subclinical hypothyroidism during pregnancy on preterm
| Variable | No. of studies |
Sample size(N)
|
Heterogeneity
|
95% CI | RR | p-value | |||
|---|---|---|---|---|---|---|---|---|---|
| Case (n) | Control (n) | p-value | I 2 (%) | ||||||
| Clinical hypothyroidism | |||||||||
| Asia | 5 | 167 | 1582 | 0.052 | 57.44 | 0.70-6.05 | 2.06 | 0.184 | |
| Europe | 5 | 19909 | 2451235 | 0.051 | 57.69 | 1.03-1.39 | 1.20 | 0.016 | |
| Test for subgroup differences: P=0.324 | |||||||||
| Subclinical hypothyroidism | |||||||||
| Asia | 9 | 2129 | 15745 | 0.005 | 63.26 | 1.12-2.29 | 1.60 | 0.009 | |
| Australia | 1 | 117 | 2134 | - | 0 | 0.06-3.59 | 0.48 | 0.482 | |
| Europe | 3 | 428 | 10559 | 0.597 | 0 | 0.96-2.15 | 1.44 | 0.072 | |
| USA | 4 | 906 | 36447 | 0.328 | 12.90 | 0.79-1.47 | 1.08 | 0.628 | |
| Test for subgroup differences: P=0.269 | |||||||||
CI: Confidence Interval
RR: Relative Risk