Table 1 Sample description, sample size, and measures of the suitability of the data for factor analysis in the studies reporting factor structure of the Pittsburgh Sleep Quality Index

Aloba et al. 2007 [31]

Nigerian College students

520

–

–

–

Anandakumar et al. 2016 [67]

outpatients at a hospital in Srilanka, 50.02 ± 13.5

205

0.83 & < 0.001

–

0.42–0.81

Babson et al. 2012 [30]

Military veterans with PTSD

226

–

–

− 0.02–0.53

Becker & Jesus 2017 [53]

Community dwelling Portugese adults, 70.05 ± 7.15

204

0.731 & < 0.001

–

0.12–0.52

Benhayon et al. 2013 [61]

Pediatric patients with Crohn disease (14.4 ± 2.3) and healthy controls (14.8 ± 2.0)

CD, n = 96

Healthy controls. N = 19

0.7 & < 0.001

–

–

Burkhalter et al. 2010 [29]

American renal transplant recipients

135

–

–

0.14–0.73

Buysse et al. 2008 [28]

Senior African-American & Caucasian adults

187

–

–

–

Casement et al. 2012 [35]

Women with PTSD

319

–

–

–

Chong & Cheung 2012 [34]

Cantonese Chinese, age > 45 years

794

–

–

0.07–0.76

Qiu et al. 2016 [58]

Pregnant women, 33.4 ± 4.2

1488

0.72 & < 0.001

–

–

Cole et al. 2006 [22]

American older adults

207, 210

–

–

0.04–0.60, 0.11–0.66

De la Vega et al. 2015 [59]

Adolescents and young adults, 17.12 ± 3.05

216

.77 & < 0.001

–

–

DeGutis et al. 2016 [62]

Trauma exposed veterans, 31.51 ± 8.16

283

–

–

–

Dudysova et al. 2017 [66]

Outpatients of the sleep laboratory at Prague psychiatric center, 44.5 ± 14.24

105

–

–

0.05–0.73

Gelaye et al. 2014 [44]

Chilean, Ethiopian, Peruvian and Thai college students

(N = 830), (N = 2230), (N = 2581), (N = 2840)

0.724 to 0.801 & < 0.001

–

–

Hita-Contreras et al. 2014 [43]

Spanish fibromyalgia patients

138

0.784 & < 0.001

–

–

Ho et al. 2014 [42]

Chinese breast cancer patients

197

–

–

0.15–0.78

Jiménez-Genchi et al. 2008 [27]

Spanish healthy controls and psychiatric patients

135

–

–

0.06–0.77

Jomeen& Martin 2007 [26]

Pregnant women with depression, 28.86 ± 55.19

180

–

–

–

Koh et al. 2015 [41]

Multi-ethnic Asians in Singapore

489, 1976

–

–

0.02–0.48, 0.05–0.36

Kotronoulas et al. 2011 [25]

Cancer patients on chemotherapy

209

.79 & < 0.001

–

.16–.70

Lequerica et al. 2014 [40]

Traumatic brain injury patients

243

–

–

–

Magee et al. 2008 [24]

Australian adults

364

–

–

< 0.43

Manzar et al. 2016a [17]

Indian university students

209, 209

0.754 & < 0.001

> 0.00001 & all values > 0.5

–

Manzar et al. 2016b [15]

Indian university students

418

0.758 & < 0.001

> 0.00001 & all values > 0.5

–

Mariman et al. 2012 [33]

Belgians with CFS

413

–

–

0.02–0.72

Nazifi et al. 2014 [39]

Iranian health professionals

415

0.58 & < 0.05

–

–

Nicassio et al. 2014 [38]

American rheumatoid arthritis patients

107

–

–

–

Otte et al. 2013 [32]

Breast cancer survivors

1172

–

–

0.18–0.51

Otte et al. 2015 [37]

Perimenopausal and postmenopausal women with hot flashes

849

–

–

0.01–0.46

Rener-Sitar et al. 2014 [46]

TMD, 37.1 ± 13.1

TMD with pain (496) & TMD without pain (113)

–

–

− 0.18 to 0.74

Salahuddin et al. 2017 [16]

Commmunity dwelling Ethiopian Adults, 25.5 ± 6.0

311

0.51, 0.52 & < 0.001, < 0.001

0.08, 0.09 & 0.39–0.67 0.48–0.64

–

Skouteris et al. 2009 [23]

Pregnant women with depression, 31.67 ± 4.55

252

–

–

–

Tomfohr et al. 2013 [36]

Community-dwelling English speaking Spanish, English and Non-hispanic white

792, 654, 1698

–

–

0.05–0.48, 0.18–0.59, 0.07–0.52

Yunus et al. 2016 [48]

Community dwelling older Malaysians

Phase 1, n = 183

Phase 2, n = 2118

–

–

–

Zheng et al. 2016 [50]

Chinese medical students, 20.2 ± 1.3

603

–

–

0.45–0.57

Zhong et al. 2015 [45]

Pregnant Peruvian women

642

0.65 & < 0.001

–

0.10 to 0.40

João et al. 2017 [57]

Portuguese community-dwelling adults, 35.93 ± 11.01

347

0.59 & < 0.001

–

0.00–0.54

Chen et al. 2017 [63]

Taiwanese insomniacs, 43.15

114

–

–

–

Khosravifar et al. 2015 [51]

Depressed and healthy Iranians, 32.3 ± 7.1

193

0.598 & < 0.001

–

–

Fontes et al. 2017 [49]

Portuguese breast cancer patients, 57.9 ± 10.8

474

–

–

–

Guo et al. 2016 [60]

Chinese undergraduate students,20.86 ± 1.33

631

–

–

–

Morris et al. 2017 [65]

Diabetic Americans male and females, 55.3 ± 11.1, 58.5 ± 10.0

198

0.60 & < 0.001

–

< 0.80

Passos et al. 2016 [52]

Brazilian adolescents, 10–19

309

0.59 & < 0.001

–

–

Zhu et al. 2018 [64]

Chinese adults with type 2 diabetes, 55.18 ± 12.65

240

0.82 & < 0.01

–

0.05–0.65