Table 6.

Adjusted means of the probability of employment and work productivity and activity impairment, by level of pain severity

DV	Pain severity	Adjusted mean	SE	95% LCL	95% UCL	P-value
Absenteeism %	Matched control	2.72	0.58	1.79	4.13	–
	Mild	1.64	0.45	0.96	2.81	0.0583
	Moderate	3.10	0.95	1.70	5.67	0.676
	Severe	6.04	2.78	2.45	14.86	0.0827
Presenteeism %	Matched control	20.48	0.99	18.62	22.51	–
	Mild	20.81	1.23	18.54	23.36	0.7772
	Moderate	36.99	2.62	32.19	42.50	<0.0001
	Severe	43.85	4.33	36.14	53.20	<0.0001
Overall work impairment %	Matched control	21.98	1.07	19.97	24.19	–
	Mild	21.88	1.32	19.44	24.62	0.935
	Moderate	38.48	2.77	33.42	44.30	<0.0001
	Severe	45.13	4.57	37.00	55.05	<0.0001
Activity impairment %	Matched control	22.15	0.71	20.80	23.58	–
	Mild	23.67	0.94	21.90	25.58	0.1036
	Moderate	42.41	1.99	38.68	46.49	<0.0001
	Severe	52.00	3.42	45.72	59.14	<0.0001
Indirect costs (¥)	Matched control	950,243	46,836	862,740	1,046,619	–
	Mild	980,778	60,060	869,852	1,105,850	0.5995
	Moderate	1,693,485	124,427	1,466,359	1,955,791	<0.0001
	Severe	1,880,516	195,266	1,534,233	2,304,957	<0.0001

Notes: Generalized linear models, specifying a negative binomial distribution and a log link function, were conducted (with the exception of employment, which used a binomial distribution and a logit function, due to its binary nature). All models adjusted for age, sex, education, annual household income, body mass index category, exercise behavior, smoking habits, alcohol consumption, and the Charlson Comorbidity Index.

Abbreviations: DV, dependent variable; LCL, 95% lower confidence limit; SE, standard error of the mean; UCL, 95% upper confidence limit.