Subclinical hypothyroidism and the metabolic syndrome: A meta-analysis of cross-sectional studies

Table 1 Characteristics of included studies

Studies	Age (yr)	Male (%)	MS criteria	Sample size	Definitionof SCH	Euthyroid			SCH			Inclusion criteria	Exclusion criteria
						No.	MS	mTSH	No.	MS	mTSH
Hergenç et al[5]	51.99	46.70	NCEP /ATPIII	488	TSH > 4.2 μU/mL	465	193	1.12	23	10	7.54	Age > 34 yr	NA
Garduño-Garcia Jde et al[6]	42.3	48.80	NCEP /ATPIII	3033	TSH: 4.5-10 mIU/L	2771	876	NA	262	84	NA	Aged 18-70 yr	Thyroid disease, diabetes, cardiovascular disease, cerebral vascular disease, amputations, pregnancy, corticosteroid use, active liver disease, and renal dysfunction
					FT4: 10-25 pmol/L
Lai et al[7]	NA	NA	NCEP /ATPIII	6254	TSH > 5.0 μU /mL	6123	1871	NA	131	43	8.5	Age > 65 yr	Taking medications for control of glucose, blood pressure, dyslipidemia, and thyroid function
					Normal FT4
Lai et al[8]	45.1	NA	China Diabetes Society	1385	TSH > 4.8 mIU/L	1283	238	NA	102	25	NA	Aged 18-85 yr	History of thyroid disease; Taking medication such as thyroxine/antithyroid drugs, glucocorticoid, antiepileptic and contraceptive drugs; Pregnant/within the first year of postpartum period; Overt hypothyroidism/hyperthyroidism
					Normal FT3/FT4
Liu et al[9]	48.9	38.20	International Diabetes Federation	6339	TSH > 4.5 mIU/L	5801	1236	2	538	138	6.5	Aged 20-88 yr	Pregnant; Severe renal, liver or heart failure, or abdominal ascites; Taking medicines influencing thyroidal function
					Normal FT3/FT4
Waring et al[10]	73.6	47	NCEP /ATPIII	2047	TSH > 0.35 mIU/L	1779	561	NA	268	98	NA	Aged 70-79 yr	Diabetes; Taking medication such as amiodarone, lithium and antithyroid medications

NCEP/ATPIII: National Cholesterol Education Program/Adult Treatment Panel III; TSH: Thyroid-stimulating hormone; MS: Metabolic syndrome; SCH: Subclinical hypothyroidism; FT4: Free thyroxine; FT3: Free triiodothyronine; NA: Not available; mTSH: mean/median thyroid-stimulating hormone level.