Table 1

Characteristics at baseline of all subjects of the Hamburg construction worker study without low back pain at baseline (n=285) who were followed up or lost to follow up

Variables		With follow up (n=230)			Lost to follow up (n=55)
Variables		Mean	SD		Median	Range	Mean	SD	Median	Range
Individual factors:
Age (y)	32.51	9.16	31	17–57	27.69	9.08	26	17–51
Body mass index (kg/m²)^1-150	25.91	4.42	25	18–41	25.69	4.61	25	18–37
Sitting height (cm)^1-151	94.72	3.53	95	85–107	94.34	2.74	94	88–103
Psychosocial work factors^1-152:
Monotonous work	2.16	1.28	2	1–5	2.87	1.48	3	1–5
Time pressure	2.90	1.32	3	1–5	2.47	1.18	2	1–5
Low job control	2.38	1.10	2	1–5	2.56	1.30	2	1–5
Poor social support	1.45	0.78	1	1–5	1.60	0.94	1	1–5
Job satisfaction	3.57	1.21	4	1–5	3.49	1.44	4	1–5

↵1-150 Subjects with missing values excluded: n=3/230 with follow up, and n=1/55 lost to follow up.
↵1-151 Subjects with missing values excluded: n=3/230 with follow up, and n=2/55 lost to follow up.
↵1-152 Measured by a five point Likert scale ranging from 1=definitely false, to 5=definitely true.