Table 1.

Summary of included studies (n = 12)

Study	Participants	Description of LBP/determination of a previous episode	Outcome measure (e.g. survey)	# that developed LBP in follow up year
Adams et al [29]	n = 403 Mean age (yr) = 27 Population = Health care workers Gender = 92% F Region: United Kingdom	History of LBP: n = 141 Pain free at baseline: not stated	Self-administered postal questionnaire, n = 399 (1% percent lost in follow up period)	n = 159 (39.5%) first time LBP
Biering-Sorensen et al [30]	n = 928 Mean age (yr) = not stated, range 30-60 Population = community members Gender = 52% F Region: Denmark	History of LBP: not stated Pain free at baseline: not stated	Self-administered postal questionnaire or telephone, n = 920 (1% percent lost in follow up period)	n = 170 (M), 185 (F) [recurrence or persistence of LBP]; n = 28 (M), 30 (F) [first time LBP 6.3%]
Feldman et al [31]	n = 810 Mean age (yr) = 14.1 Population = Adolescent students Gender = 47% F Region: Canada	History of LBP: n = 125 Pain free at baseline: not stated	Self-administered questionnaire, n = 502 (38% lost in follow up period)	n = 65 developed first time LBP (17.2%))
Fortin et al [40]	n = 99 Mean age (yr) = 47.3 Population = Monozygotic twins Gender = 0% F Region: Finland	History of LBP: 68 Pain free at baseline: not stated	Numeric pain scale, n = 98 (1% lost in follow up period)	n = 68 (recurrence or persistence of LBP, 69.4%)
Gibbons et al [32]	n = 130 Mean age (years) = 48 Population = Twins Gender = 0% F Region: Finland	History of LBP: n = 85 (in past year) Pain free at baseline: yes	Telephone, n = 128 (2% lost in follow up period)	n = 13 developed first time LBP (out of 43 that reported no history of LBP at baseline, 30.2%)); n = not reported for those 85 participants that declared a history of LBP in 12/12 before baseline testing
Kanchanomai et al [33]	n = 684 Mean age (years) = 19.4 Population = University students Gender = 74% F Region: Thailand	History of LBP: n = 0 (in past 3 months) Pain free at baseline: yes	Self-administered questionnaire, n = 524 (23% lost in follow up period)	n = 160 (23.4%) developed first time LBP
Kountouris et al [34]	n = 23 Mean age (years) = 24 Population = Elite fast bowlers Gender = 0% F Region: Australia	History of LBP: n = not stated Pain free at baseline: yes	Sports Medicine Physician and MRI, n = 23 (0% lost in follow up period)	n = 18 developed first time LBP (72.3%)
Kujala et al [35]	n = 138 Mean age (years) = not stated, range 10.3-13.3 Population = athletes and non-athletes Gender = not stated, 56% F at follow up Region: Finland	History of LBP: n = 28 (in past year) Pain free at baseline: not stated	Self-administered postal questionnaire, n = 119 (14% lost in follow up period)	n = 24 (11 recurrence of LBP [39.3%], 13 first time LBP [11.8%)
Luoto et al [36]	n = 167 Mean age (years) = not stated Population = blue and white collar workers Gender = 56% F Region: Finland	History of LBP: n = 0 (in past year) Pain free at baseline: yes	Nordic questionnaire, n = 126 (25% lost in follow up period)	n = 33 developed first time LBP (19.8%)
Milgrom et al [37]	n = 395 Mean age (years) = 18 Population = infantry recruits Gender = 0% F Region: Israel	History of LBP: n = 0 Pain free at baseline: not stated	Physical examination, n = not clear how many were lost in follow up period	n = 40 developed first time LBP (10.1%)
Nissinen et al [39]	n = 859 Mean age (years) = 12.8 Population = School children Gender = 48% F Region: Finland	History of LBP: n = 0 (in past year) Pain free at baseline	Self-administered standardised pain questionnaire, n = 859 (0% lost in follow up period)	n = 151 developed first time LBP (17.6%)
Van Nieuwenhuyse et al [38]	n = 823 Mean age (years) = 26 Population = workers at health care and distribution facilities Gender = 60% F Region: Belgium	History of LBP: n = 337 (in past year) Pain free at baseline: n = 688 (4 of the participants with history of LBP reported LBP at baseline)	Self-administered questionnaire, n = 692 (16% lost in follow up period)	n = 34 developed first time LBP (out of 355 that reported no history of LBP at baseline, 9.6%), n = 52 (out of 337 that reported LBP in 12/12 before testing, 15.4%)

F female, M male, LBP low back pain