Table 1 The characteristic of included case–control and cohort studies in this meta-analysis

Alipour et al. [20] (2018)

Women with fibrocystic changes (FCC) and women who had attended the clinic for breast cancer screening without any breast symptoms

Case = 40 ± 8.8

Control = 46 ± 9.8

320

Case = 114

Control = 206

Breast clinical features or ultrasonographic and histological detection of FCC

TSH ≥ 5 (μIU/mL)

1.52 (0.61, 3.78)

Age, body mass index

(BMI), and family history of BBD

Anil et al. [21] (2015)

Patients with HT, subjects without known thyroid disease, who attended the Endocrinology Department for general Endocrine check-up

Case = 37.66 ± 8.41

Control = 32.59 ± 7.32

(18_50)

167

Case = 95

Control = 72

Breast ultrasonography

Thyroid ultrasonography, positive anti-TPO (antithyroid peroxidase)

2.81 (0.84, 9.40)

Gungor et al. [16] (2020)

Women with Irregular Menstruation, and Polycystic Ovary Syndrome, who applied to the Gynecology and Obstetrics outpatient clinic

Case = 33.02 ± 1.99

Control = 33.2 ± 1.9

269

Case = 102

Control = 167

Breast ultrasound

Based on the Rotterdam 2003 diagnostic criteria

1.41 (0.86, 2.31)

Age _BMI Mean age at menarche _smoking

Soran et al. [17] (2005)

Women with PCOS and healthy from the population of a cohort study

Case = 46 (30–66)

Control = 47 (29–63)

240

Case = 116

Control = 124

Clinical or histological diagnosis

Through private reproductive endocrine practices

0.78 (0.45, 1.36)

Age, Race

Gumus et al. [18] (2009)

PCOS and non- PCOS

Case = 25 ± 4.98

Control = 26.4 ± 5.09

93

Case = 53

Control = 40

Ultrasound examination

Laboratory, clinical, and ultrasound findings

3.17 (1.31–7.68)

Age, body mass Index (BMI)

D’Amelio et al. [19] (2001)

Women who attend the outpatient ultrasound clinic

26 ± 1

(18–30)

444

Case = 93

Control = 351

Ultrasound mammography

Pelvic ultrasound scan

18.05 (10.07, 32.35)

Age, parity, menstrual patterns, body mass index (BMI)