Table 2 Association between positive questionnaire in 1993–4 and upper extremity musculoskeletal disorders (UEMSD) diagnosed by physical examination in 1996–7 (cases), stratified on age

	All workers								Workers without any UEMSD diagnosed in 1993–4
	Age <40 years old				Age ⩾40 years old				Age <40 years old				Age ⩾40 years old
	n*	Cases, n(1996–7)	%	p Value†	n*	Cases, n(1996–7)	%	p Value†	n*	Cases, n(1996–7)	%	p Value†	n*	Cases, n(1996–7)	%	p Value†
Negative questionnaire in 1993–4	140	61	43.6	<0.001	16	8	50.0	<0.01	120	46	38.3	<0.05	14	6	42.9	NS
Positive questionnaire in 1993–4	338	265	78.4		104	89	85.6		34	20	58.8		9	6	66.7
Total	478	326	68.2		120	97	80.8		154	66	42.9		23	12	52.2

*Number of subjects.
†χ² or Fisher exact tests.