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Table 1 Characteristics of included studies examining the association between β-carotene intake and risk of fractures

From: Effects of β-carotene intake on the risk of fracture: a Bayesian meta-analysis

Author, year Study design Sample size Percent of Women Fracture outcomes Mean age Exposure assessment Covariate adjustmenta Country NOS score Items that did not earn a NOS score
Feskanich, 2002 [24] Cohort 72,337 100 Hip fracture 60 FFQ: Self-reported 1, 7, 8, 14, 15, 16, 17, 18, 19, 20 USA 7 - Study controls for any additional factor
- Complete follow up, all subjects accounted for
Zhang, 2006 [18] C-C 2564 69.2 Hip fracture 75.2 FFQ: Self-reported 1, 2, 8, 9, 11, 12, 14, 18, 19, 21 USA 9  
Sahni, 2009 [17] Cohort 1046 61 Hip fracture 75 FFQ: Self-reported 1, 2, 8, 9, 12, 14, 19, 21, 22 USA 8 - Truly representative of the average sample in the community
Ambrosini, 2013 [19] Cohort 2322 28.6 Any fracture 55 Medical records 1, 2, 6, 8, 14, 23 Australia 5 - Truly representative of the average sample in the community
- Independent blind assessment
- Study controls for any additional factor
- Complete follow up, all subjects accounted for
Sun, 2014 [20] C-C 1452 NA Hip fracture 70.5 FFQ: Self-reported 1,2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14 China 7 - Consecutive or representative series of cases
- Community controls
Dai, 2014 [23] Cohort 63,154 55.8 Hip fracture 56.3 FFQ: Self-reported 1, 3, 8, 9, 11, 12, 14, 15, 24, 25, 26, 27, 28 Singapore/China 7 - Complete follow up, all subjects accounted for
- Independent blind assessment
Jonge, 2015 [22] Cohort 5288 58.9 Any fracture 67 FFQ: Self-reported 1, 2, 3, 5, 8, 9, 11, 14, 29 Netherland 8 - Selected an adequate follow up period for outcome of interest
Hayhoe, 2017 [37] Cohort 40,242 55.3 Any/hip/spine fracture 60.8 7-day food diaries 1, 6, 7, 8, 9, 11, 12, 14, 15, 30, 31 UK 9  
Cao, 2018 [21] C-C 2140 74.1 Hip fracture 70.6 FFQ: Self-reported 1, 3, 4, 5, 6, 7, 8, 10, 11, 12, 14, 32 China 5 - Consecutive or representative series of cases
- Study controls for any additional factor
- Same method of ascertainment for cases and controls
- Same non-response rate for both groups
  1. Abbreviations: C-C case-control, FFQ food frequency questionnaire, NA not available, UK United Kingdomm, US United States,
  2. aAge (1), sex (2), educational level (3), occupation (4), household income (5), family history of fracture (6), smoking status (7), alcohol intake (8), calcium use (9), multivitamin supplement use (10), physical activity (11), daily energy intake (12), dietary intake of selected nutrients (13), body mass index (14), use of postmenopausal hormones (15), hours of leisure-time activity (16), use of thiazide diuretics (17), protein use (18), vitamin D (19), vitamin K (20), caffeine use (21), height (22), medication use (23), dialect group (24), vitamin B6 (25), soy isoflavones (26), history of diabetes and stroke (27), use of hormone replacement therapy (28), disability index (29), hormone replacement therapy (30), corticosteroid use (31), and calcium supplement use (32)