Table 2.

Effect of age on work and productivity impairment among workers with osteoarthritis.

WPAI Question	40-64 years of age (n = 1,339)		≥ 65 years of age (n = 515)
	Rate ratio (95% CI)	p-value	Rate ratio (95% CI)	p-value
Absenteeism	0.707 (0.614, 0.815)	< 0.0001	0.376 (0.289, 0.489)	< 0.0001
Presenteeism	0.733 (0.698, 0.769)	< 0.0001	0.406 (0.369, 0.445)	< 0.0001
Overall work impairment	0.737 (0.702, 0.773)	< 0.0001	0.421 (0.384, 0.462)	< 0.0001
Activity impairment	0.778 (0.745, 0811)	< 0.0001	0.512 (0.472, 0.555)	< 0.0001

Rate ratios, adjusted for other covariates, are relative to the referent of workers 20-39 years of age (n = 338). A rate ratio < 1 indicates a reduction relative to the referent, and the reciprocal of the rate ratio indicates the magnitude of the reduction