Table 3.

Association between poor work ability* (A) and sleep disturbances† (B) and long-duration activity limiting neck and/or back pain

Cases/all	Crude RR	95% CI	Model 1‡ adjusted RR	95% CI	Model 2§¶ adjusted RR	95% CI
A
Good work ability	842/10 011	ref		ref		ref
Poor work ability*	214/1218	2.1	1.8 to 2.4	1.8	1.6 to 2.1	1.7	1.4 to 2.0
B
Good sleep	625/7833	ref		ref		ref
Sleep disturbances†	411/3257	1.6	1.4 to 1.8	1.5	1.3 to 1.7	1.4	1.2 to 1.5

*WAI (Work Ability Index) items, self-perceived physical and/or mental work ability in relation to job demands and defined as moderate, rather poor, poor.

†Sleep disturbances=current mild or severe sleep disturbances.

‡Adjusted for socioeconomic status, chronic comorbidity and subsample (years 2002, 2006, 2010).

§Adjusted for socioeconomic status, chronic comorbidity, sleep disturbances and subsample (years 2002, 2006, 2010).

¶Adjusted for socioeconomic status, chronic comorbidity, work ability and subsample (years 2002, 2006, 2010)

RR, risk ratio.