Table 5.

Variables describing potential determinants of exposure. Coefficients, standard error (SE) and P-value for fixed effect included in a mixed effect model for all factories, and for factories included in both studies 1 and 2

Determinants of exposure	All 68 factories				27 Factories included in both studies 1 and 2
	Coefficient	SE	P-value	% Change (95% CI)a	Coefficient	SE	P-value
Intercept	0.03	0.08	—		−0.003	0.10	—
Study (ref. study 1)	−0.54	0.04	<0.0001	−41 (−36; −46)	−0.52	0.05	—
Personal level
Use of compressed air	0.13	0.03	<0.0001	14 (8; 20)	0.11	0.04	<0.01
Day shift	0.06	0.03	0.06	NS	0.06	0.04	0.16
Machine level
Handling/assembling	−0.03	0.06	0.60	NS	−0.02	0.07	0.16
Manual task	0.17	0.05	<0.001	17 (8; 30)	0.22	0.06	0.01
Sanding	0.42	0.10	<0.001	53 (36; 86)	0.44	0.13	<0.001
Fully automatic task	0.15	0.05	<0.01	16 (5; 27)	0.19	0.06	<0.01
Adequate exhaust ventilation	−0.10	0.05	0.04	−10 (−0; −18)	−0.09	0.06	0.06
Encapsulation	−0.03	0.04	0.48	NS	−0.07	0.06	0.20
Use of hardwood	0.09	0.08	0.27	NS	−0.08	0.09	0.38
Department level
Cleaning of work pieces with compressed air	0.14	0.06	0.01	15 (3; 28)	0.12	0.07	0.09
Vacuum cleaning machines	−0.13	0.05	0.02	−12 (−2; −21)	−0.13	0.07	0.06
Kitchen production	0.17	0.09	0.04	19 (0; 41)	0.25	0.12	0.05
Factory level
Factories <20 employees	0.24	0.10	0.02	27 (4; 55)	0.25	0.18	0.17
Special cleaning staff	−0.12	0.05	0.01	−12 (−3; −19)	−0.18	0.06	<0.01
Handling/assembling × manual	−0.28	0.07	<0.001	−25 (−13; −35)	−0.35	0.10	<0.001
Sanding × adequate exhaust ventilation	−0.35	0.14	0.01	−29 (−7; −46)	−0.35	0.18	0.06

The dependent variable was the log_e-transformed dust concentration.

^aThe percent change in dust level caused by each determinant b was calculated as (1 – exp(b_coefficient)) × 100. NS: non-significant.