Table 1.

Baseline characteristics of the participants

	Pain status	N	mean	Range	SD
Age	No pain	109	45	23-69	8.6
(years)	Pain	85	45	24-58	8.2
Height	No pain	109	162	142-180	7.7
(cm)	Pain	85	161	148-180	7.2
Weight	No pain	109	72	44-115	16.1
(kg)	Pain	85	72	49-110	13.2
Length of employment	No pain	88	9	1-27	7.3
(years)	Pain	70	9	0-29	8.4

Age, height, weight and length of employment of cleaners

N = number of participants, SD = standard deviation.