Osteocalcin Serum Levels in Gestational Diabetes Mellitus and Their Intrinsic and Extrinsic Determinants: Systematic Review and Meta-Analysis

Table 1

Characteristics of included studies.

Study	Year	Country	Type of study	Inclusion criteria	Exclusion criteria	Diagnostic criteria for GDM	Type of osteocalcin	Analysis method	Study participants	Number of nondiabetic women	Number of diabetic women
Winhofer	2010	Iran	Case control	Healthy pregnant women, who were referred from the department of obstetrics and gynecology to the outpatient clinic for routine glucose tolerance testing between the 24th and 28th gestational weeks	History of GDM or obstetric complications in a previous pregnancy, any history of impaired glucose tolerance, or signs of fetal macrosomia. Previous OGTT during pregnancy	One-step: 75 g of glucose (5.5, 10.0, and 7.8 mmol/l cutoff at 0, 1, and 2 h)	ucOC	ELISA for tOC	78	52	26
Hossein-nezhad	2010	Iran	Case control	Pregnant women without previous history of diabetes mellitus who referred to the clinics for prenatal care during the first half of the pregnancy	None	Two-step: 50 g if >7.2 mmol/L, 100 g	tOC	ELISA	695	644	51
Tabatabaei	2014	Canada	Cohort	Healthy pregnant Caucasian women and women with GDM having singleton and term pregnancies with gestation duration of 37 to 42 weeks. With high risk of GDM (obesity and previous history of GDM)	History or new diagnosis of corticosteroid-treated asthma, liver disease, renal disease, Crohn’s disease, ulcerative colitis, celiac disease, medication known to affect bone metabolism, and history of type 1 diabetes or type 2 diabetes	Two-step: 50 g if >7.2 mmol/L, 100 g	ucOC	ELISA	96	48	48
Saucedo	2015	Mexico	Case control	Nongestational diabetic women and gestational diabetic women screened at 24–28 weeks	History of arterial hypertension, renal disease, liver disease, thyroid disorders, and other endocrine or chronic diseases	Two-step: 50 g if >7.2 mmol/L, 100 g	tOC & ucOC	IRA for tOC & ELISA for ucOC	120	60	60
Srichomkwun	2015	Thailand	Case control	Pregnant women without risk of gestational diabetes mellitus	History of DM before pregnancy, twin or multiple pregnancy, or significant medical problem, such as cardiovascular, liver, or renal disease	Two-step: 50 g if >7.2 mmol/L, 100 g (cutoff Carpenter Coustan 5.3, 10.0, 9.2, and 8.1 mmol/L at 0, 1, 2, and 3 h	tOC & ucOC	ELISA	130	56	74

tOC: total osteocalcin; ucOC: undercarboxylated osteocalcin; ELISA: electrochemiluminescence immunoassay; IRA: immunoradiometric assay; GDM: gestational diabetes mellitus.