Table 1

Description of four articles reporting on five studies on puberty and back pain

Reference number	[ 33 ]	[ 33 ]	[ 35 ]	[ 34 ]	[ 32 ]
1st author	Jansens	Jansens	Wedderkopp	LeResche	Hulsegge
Year	2011	2011	2005	2005	2011
Country	Netherland	USA	Denmark	USA	Netherland
Design	Longitudinal	Longitudinal	Cross-sectional	Cross-sectional	Cross-sectional
Sample size	BL: 2935	BL: 4079	419	3101	2698
	FU: 1816	FU: 1817
Response rate	BL:76%	BL: 49%	51%	49%	66%
	1st FU: 73%	FU: 45%
	2nd FU: 62%
Age	BL: 11.1	BL: 11	8-10 and 14-16	11-17	11
	FU: 15.1	FU: 14
Sex distribution (% of girls)	51	51	100	50	49
Description of puberty	4 stages	4 stages	5 stages	4 stages	4 stages
Data collection for puberty	Questionnaire PDS	Telephone itw PDS	Physical examination Tanner stages	Telephone itw PDS	Questionnaire PDS
Description of back pain	BP = frequency	BP = frequency	BP = areas (LBP/MBP/NP)	BP = duration (>one day or more)	BP = duration (>1 month)
Data collection for back pain	Questionnaire	Telephone itw	Semi-structured itw	Telephone itw	Questionnaire
Recall period for back	3 months	3 months	1 month	3 months	12 months
Other extrinsic factors than age and sex	Pubertal status at BL	Pubertal status at BL	Overweight Smoke	Previous pain Depression	Not in the analysis for back pain
	BP at BL	BP at BL
Dose–response analysis possible	Prevalence estimate AND frequency of symptoms in relation to puberty stages	Prevalence estimate AND frequency of symptoms in relation to puberty stages	Prevalence estimate in relation to puberty stages	Prevalence estimate in relation to puberty stages	Prevalence estimate in relation to puberty stages

BL = baseline
FU = follow up
Itw = interview
PDS = pubertal development scales
BP = back pain.