Table 5.

Description of silica-smoking and diesel-smoking interaction studies included in the systematic review

Author (Year)	Study design	Geographic area	Industry type	Outcome identification	Silica				Smoking			NOS
					Data collection	Exposure Identification	Non exposed	Exposed	Data collection	Non Smoker	Smoker
Silica-smoking interaction studies
Liu (2013) [36]	Prospective cohort	China	Metal mines and pottery factories	-Hospital record -Death certificate	Employment record	Matrix	Never	Ever	Interview	Never	Ever	8
Fu (1994) [37]	Nested case–control	Guangxi province (China)	Tin miners	Death Certificate	-Employment record -Questionnaire	Expert	Never	YUED	Questionnaire	Never	P.Y	7
Cassidy (2007) [38]	Multicenter hospital-based case–control	Europe	Undetermined	Hospital	Questionnaire	Industrial hygienist	Never	Ever	Questionnaire	Never	-Former -Current	7
De Matteis (2012) [6]	Population-based case–control	Italy	Undetermined	Hospital	-Questionnaire -Interview	Matrix	Never	Ever	-Questionnaire -Interview	Never	-Former -Current	6
Kachuri (2014) [39]	Population-based case–control	Canada	Undetermined	Register	Self-reported questionnaire	Industrial hygienist	Never	≥30 Y	Self-reported questionnaire	<10 P.Y	≥40 P.Y	8
Consonni (2015) [40]	Pooled case–control	Europe, Canada, Hong Kong and New Zealand	Bricklayers	-Register -Hospital	Questionnaire	Matrix	Never bricklayers	Ever bricklayers	Questionnaire	Never	Ever	8
Lacourt (2015) [34]	Pooled case–control	Montreal (Canada)	Construction	Hospital	Questionnaire	Expert	Never	Substantial	Questionnaire	Never-low	Medium-heavy	7
Diesel-smoking interaction studies
Silverman (2012) [41]	Nested case–control	USA	Non-metal mining facilities	-Register -Death certificate	Computer-assisted telephone interview	Measures	Never	Tertiles	Computer-assisted telephone interview	Never	≥2 P.D	8
Pintos (2012) [42]	Pooled case–control	Canada	Wide range of occupations and industries	Incident case	Questionnaire	-Chemist -Industrial hygienist	Never	Substantial	Questionnaire	Never-low (0–15 P.Y)	Medium-heavy (>15 P.Y)	7

NOS the Newcastle-Ottawa quality assessment Scale, S current smokers, Y years, YUED Years of Underground Exposure to Dust, P.Y Pack.Year