Conclusions, the number of MAs, average CC/CO/CS studies and patients and average AMSTAR score about the association between SCH and other diseases
| Conclusions | No of included MAs | Average CC/CO/CS studies included | Average patients included | Average AMSTAR score |
| Plasma homocysteine levels were not found to be significantly higher in patients with SCH58 | 1 | 3/5/0 | 926 | 10.00 |
| SCH is not significantly associated with fractures30 52 54 | 3 | 0/8/0 | 128 667 | 9.7 |
| SCH was associated with increased risk of any location of fractures, hip fractures and forearm fractures60 | 1 | 0/13/0 | 62 490 | 10 |
| No evidence which could prove a definite association between SCH and the risk of fracture79 | 1 | 0/6/0 | 289 575 | 7 |
| Serum TC, LDL-C and TG levels were significantly increased in patients with SCH compared with euthyroidism individuals. No significant difference was observed for serum HDL-C36 42 | 2 | 5/0/7 | 22 767 | 9.00 |
| SCH is associated with a significant decrease in fasting plasma glucose36 | 1 | 3/0/1 | 3507 | 9.00 |
| SCH is not significantly associated with BMI36 | 1 | 7/0/1 | 3971 | 9.00 |
| SCH was associated with a significant increase in SBP31 36 56 | 3 | 1.7/2/7 | 23 485 | 8.00 |
| SCH was associated with a significant increase in DBP31 | 1 | 0/0/6 | 17 323 | 8.00 |
| SCH is not significantly associated with increased DBP36 56 | 2 | 1.7/1.7/5 | 25 810 | 8.00 |
| SCH is associated with a significant increase in C-IMT36 59 66 75 | 4 | 6.75/3.5/0.5 | 2420 | 8.75 |
| SCH has a significant association with arterial wall thickening and stiffening and endothelial dysfunction and increased risk of cardiovascular events59 | 1 | 27/0/0 | 1931 | 9 |
| SCH is significantly associated with an increased risk for CHD50 63 | 2 | 0/6.5/1 | 8528 | 7.5 |
| SCH is not significantly associated with an increased risk for CHD28 44 77 | 0/9.3/0 | 18 525 | 7.30 | |
| SCH is significantly associated with an increased risk for cardiovascular mortality50 63 | 2 | 0/3.5/0.5 | 6525 | 7.5 |
| SCH is not significantly associated with an increased risk for cardiovascular mortality28 44 | 2 | 0/10/0 | 33 444 | 8.00 |
| SCH is not significantly associated with an increased risk for all-cause mortality28 44 50 | 3 | 0/6.3/0.3 | 24 853 | 7.00 |
| SCH is significantly associated with MetS as defined by the IDF Criteria55 | 1 | 0/0/2 | 7258 | 10.00 |
| SCH is not significantly associated with MetS as defined by the NCEP-ATP III Criteria34 55 | 2 | 2/0/5 | 24 717 | 10.00 |
| SCH is not significantly associated with MetS as defined by the Chinese Criteria55 | 1 | 0/0/1 | 1399 | 10.00 |
| SCH is not significantly associated with MetS as defined by the Japanese Criteria55 | 1 | 0/0/2 | 10 350 | 10.00 |
| SCH is not significantly associated with cognitive impairment29 45 47 | 3 | 0/8.3/4.3 | 16 833 | 9.33 |
| SCH patients had significantly worse parameters of left ventricular diastolic function than euthyroid subjects aged <60 years33 | 1 | 0/0/14 | 675 | 7.00 |
| SCH is significantly associated with a risk factor for gestational diabetes37 | 1 | 0/6/0 | 63 567 | 7 |
| SCH can significantly increase the risk of diabetic retinopathy in T2DM patients38 53 | 2 | 0/8.5/0.5 | 4101 | 9.5 |
| SCH can significantly increase the risk of diabetic nephropathy in T2DM patients38 62 | 2 | 6/0/1.5 | 2653 | 8.5 |
| SCH can significantly increase the risk of diabetic peripheral neuropathy in T2DM patients38 | 1 | 3/0/0 | 1710 | 10 |
| SCH can significantly increase the risk of peripheral arterial disease in T2DM patients38 | 1 | 4/0/0 | 801 | 10 |
| SCH is not significantly associated with coronary heart disease in T2DM patients38 | 1 | 7/0/0 | 1896 | 10 |
| SCH is a significant risk factor of chronic kidney disease in T2DM patients78 | 1 | 4/0/2 | 38 284 | 6 |
| No significant correlation was found between SCH and stroke32 | 1 | 0/5/0 | 10 118 | 10 |
| SCH does not influence the hormonal profile of women with polycystic ovary syndrome. But it results in mild metabolic abnormalities in a short-term setting66 | 1 | 0/12/0 | 2341 | 10 |
| Maternal SCH is not significantly associated with the occurrence of preterm birth48 | 1 | 0/10/0 | 48 684 | 8 |
| Maternal SCH significantly increases the risk of preterm birth41 59 64 71 | 4 | 0/14.1/0 | 110 951 | 9.3 |
| Maternal SCH is significantly associated with the risk for intrauterine growth restriction51 64 | 2 | 0/5/0 | 12 558 | 8.5 |
| Maternal SCH has a significant adverse affect on the intelligence of offspring35 46 76 | 3 | 1/0/37 | 303 360 | 8.3 |
| SCH patients have a higher prevalence of miscarriage67 | 1 | 0/3/0 | 6036 | 9 |
| Children of women with SCH were found have a significant lower mean motor scores than those of euthyroidism35 | 1 | 0/1/0 | 160 | 10 |
| No significant association was found between NAFLD and SCH72 | 1 | 0/1/4 | 26 454 | 10 |
AMSTAR, Assessment of Multiple Systematic Reviews; BMI, body mass index; CC/CO/CS, case–control/cohort/cross-sectional; CHD, coronary heart disease; C-IMT, carotid intima-media thickness; DBP, diastolic blood pressure; HDL-C, high-density lipoprotein cholesterol; IDF, International Diabetes Federation; LDL-C, low-density lipoprotein cholesterol; MAs, meta-analyses; MetS, metabolic syndrome; NAFLD, non-alcoholic fatty liver disease; NCEP-ATP III, National Cholesterol Education Programme’s Adult Treatment Panel III; SBP, systolic blood pressure; SCH, subclinical hypothyroidism; TC, total cholesterol; TG, total triglyceride; T2DM, type 2 diabetes mellitus.