Table 1.

Characteristics of the patient and the population samples.

	Population sample			Patient sample			P-value1
	Men	Women	Total	Men	Women	Total
	600	705	1305	25	163	188
Age, mean (sd)	47.4 (14.1)	46.8 (14.3)	47.1 (14.2)	52.4 (14.7)	56.0 (10.8)	55.5 (11.5)	<0.0001
QEESI (median)							P-value2
Symptoms	9.0	14.0	11.0	35.0	48.0	47.0	<0.0001
Chemical Int.	11.0	15.0	13.0	81.6	82.2	82.1	<0.0001
Other Int.	6.0	12.0	10.0	27.3	35.5	35.0	<0.0001
Life Impact	0.0	3.0	2.0	70.0	64.0	65.0	<0.0001
Masking Index	4.0	4.0	4.0	2.0	2.0	2.0	<0.0001
SCL-92 (median)
Depression	0.15	0.31	0.23	0.62	0.69	0.69	<0.0001
Somatisation	0.25	0.33	0.33	0.83	1.0	1.0	<0.0001
SCL-92 (mean)
Depression	0.39	0.53	0.47	1.0	0.86	0.88	—
Somatisation	0.38	0.51	0.45	1.0	1.13	1.12	—
Occupational social class (n (%))							P-value3
							<0.0001
I + II:			224 (17.2)			17 (9.0)
III + IV:			426 (32.6)			35 (18.5)
V + VI + VII:			566 (43.4)			124 (65.6)
Missing:			89 (6.8)			13 (6.9)

Occupational social class: I + II: professionals and executives and medium-level white-collar employees; III + IV: low-level white-collar employees and skilled workers; V + VI + VII: unskilled and semiskilled workers, individuals receiving pension or disability benefits, and students.

¹Independent samples  t-test for equality of means (total) between population and patient samples.

²Mann-Whitney test (total) comparing population and patient samples.

³Chi-squared test comparing population and patient samples.