Differences in risk factors for neurophysiologically confirmed carpal tunnel syndrome and illness with similar symptoms but normal median nerve function: a case–control study

Table 3 Associations with non-occupational risk factors according to neurophysiological findings

Risk factor	Controls	NP+ve cases			NP-ve cases
	n	n	OR^a	(95% CI)	n	OR^a	(95% CI)
BMI (Kg/m ² )
<25	303	118	1		154	1
≥25 and <30	254	162	1.6	(1.2-2.2)	151	1.2	(0.9-1.6)
≥30	220	184	2.3	(1.7-3.1)	93	0.9	(0.7-1.2)
Missing	22	11	1.2	(0.5-2.6)	11	0.9	(0.4-1.9)
Smoking habits
Never smoked	367	251	1		209	1
Ex-smoker	210	136	1.1	(0.8-1.4)	97	0.9	(0.7-1.2)
Current smoker	213	83	0.6	(0.5-0.8)	101	0.8	(0.6-1.1)
Missing	9	5	0.6	(0.2-2.3)	2	0.4	(0.1-2.0)
Other disease ^b
Diabetes	56	37	1.1	(0.7-1.7)	18	0.7	(0.4-1.2)
Rheumatoid arthritis	32	23	1.3	(0.8-2.3)	19	1.3	(0.7-2.3)
Other arthritis	169	92	1.0	(0.8-1.4)	92	1.3	(1.0-1.8)
Mental health
Good	333	170	1		157	1
Intermediate	236	155	1.2	(0.9-1.7)	142	1.4	(1.0-1.8)
Poor	225	148	1.3	(1.0-1.8)	108	1.1	(0.8-1.5)
Missing	5	2	0.5	(0.1-3.7)	2	0.9	(0.2-4.8)
Number of somatic symptoms at least moderately distressing in past week
0	234	130	1		93	1
1	193	123	1.1	(0.8-1.6)	110	1.5	(1.1-2.1)
≥2	372	222	1.1	(0.8-1.4)	206	1.5	(1.1-2.0)

^aAdjusted for sex and age (in 10-year strata) and ethnicity.
^bRisk estimates are for those with the disease relative to those who did not have it.

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