Table 2 Quality assessment of four articles reporting on five studies on puberty and back pain

1. Study sample

- Was the sampling likely to be suitable to obtain a group representative of the corresponding general population?

Yes (Probably)

Yes (Probably)

Yes (Probably)

Yes (Probably)

Yes (Probably)

- If participation at BL or at FU < 80%, was response bias investigated?

Yes

Yes

Yes

Yes

No

- Inclusion criteria, were age groups appropriate to study the whole period of puberty?

Yes

Yes

Yes

Yes

Not really

2. Data collec-tion

- Data for BP and puberty were collected independently by 2 different persons or by at least 1 questionnaire?

Yes

No

Yes

No

Yes

3. Puberty

- Clearly defined?

Yes

Yes

Yes

Yes

Yes

- Description of how puberty stage was determined?

Yes

Yes

Yes

Yes

Yes

-Reference provided for validity of test?

No

No

No

Yes

Yes

-Reference provided for reliability of test?

Yes

Yes

No

No

No

4. Back pain

- Clearly defined?

Yes

Yes

Yes

Yes

Yes

- Description of how BP was assessed?

Yes

Yes

Yes

Yes

Yes

- Recall period (<= 1-month)?

No

No

Yes

No

No

- Was BP at BL taken into account?

Yes

Yes

NA

NA

NA

5. Control for age and sex

- Was the association puberty- BP controlled for age?

Yes

Yes

Stratified analysis

Yes

Yes

- for sex?

Yes

Yes

NA

Stratified analysis

Yes

6. Stat. analysis

- Was dose-response prevalence estimated in relation to puberty stages investigated?

Yes

Yes

Yes

Yes

No

- Was dose-response of frequency or severity in relation to puberty stages investigated?

No

No

NA

NA

NA

- Was dose-response tested for trend?

Yes

Yes

Yes

Yes

Yes

14/17

13/17

12/14

12/15

10/15

82%

76%

86%

80%

67%