Occupational Exposure to Talc Increases the Risk of Lung Cancer: A Meta-Analysis of Occupational Cohort Studies

Table 2

Lung cancer risk of talc-exposed cohorts eligible for meta-analysis.

Reference/location	Newcastle-Ottawa Scale (NOS)				Cases	Type of RR	RR	95% CI	Mortality, all causes
	Selection	Comparability	Outcome	Overall quality
Bulbulyan et al., Russia, 1999	(+) (+) (+) ( )	(+) (+)	(+) (+) (+)	High (8)	6	SMR	1.00	0.37–2.18	0.98
Coggiola et al., Italy, 2003	(+) (+) (+) ( )	(+) (+)	(+) (+) (+)	High (8)	44	SMR	0.94	0.68–1.26	1.20
Fu and Zhang, China, 1992	(+) ( ) (+) ( )	(+) (+)	(+) (+) (+)	Medium (7)	15	SMR	2.22	1.24–3.66	1.27
Honda et al., USA, 2002	(+) (+) (+) ( )	(+) (+)	(+) (+) (+)	High (8)	31	SMR	2.38	1.57–3.29	1.31
Li and Yu, China, 1998	(+) (+) (+) ( )	(+) (+)	(+) (+) (+)	High (8)		SMR	1.48	0.40–3.79	1.16
McLean et al., multinational, 2006	(+) (+) (+) ( )	(+) (+)	(+) (+) (+)	High (8)		SMR	0.96	0.73–1.24	0.88
Nie et al., China, 1992	(+) (+) (+) ( )	(+) (+)	(+) (+) ( )	Medium (7)	5	SMR	4.50	1.46–10.50	1.78
Stern et al., USA, 2001	(+) (+) (+) ( )	(+) (+)	(+) (+) (+)	High (8)	1386	PMR	1.39	1.32–1.47	1.00
Selevan et al., USA, 1979	(+) (+) ( ) ( )	(+) (+)	(+) (+) (+)	Medium (7)	7	SMR	2.25	0.09–3.69	1.22
Straif et al., Germany, 2000	(+) (+) (+) (+)	(+) (+)	(+) (+) (+)	High (9)	154	SMR	1.23	1.04–1.44	1.03
Thomas and Stewart, USA, 1987	(+) (+) (+) ( )	(+) (+)	(+) (+) (+)	High (8)	21	SMR	2.54	1.57–3.88
Wergeland et al., Norway, 1990	(+) (+) (+) ( )	(+) (+)	(+) (+) (+)	High (8)	6	SIR	0.92	0.34–2.01	0.75
Wild et al., Austria, 2002	(+) (+) (+) ( )	(+) (+)	(+) (+) (+)	High (8)	7	SMR	1.06	0.43–2.19	0.75
Wild et al., France, 2002	(+) (+) (+) ( )	(+) (+)	(+) (+) (+)	High (8)	21	SMR	1.24	0.76–1.89	0.93

The items of Newcastle-Ottawa Scale (NOS) for cohort studies are categorized into selection, comparability, and outcome. The list of items: representativeness of the exposed cohort (Selection-1), selection of the nonexposed cohort (Selection-2), ascertainment of exposure (Selection-3), demonstration that outcome of interest was not present at start of study (Selection-4), comparability of cohorts on the basis of the design or analysis (Comparability-1), assessment of outcome (Outcome-1), long enough follow-up for outcomes to occur (Outcome-2), and adequacy of follow-up of cohorts (Outcome-3). The SMR (observed cases = 3, expected cases = 2.4) was calculated based on the workers engaged in the production of tires and inner tubes, who were categorized as the talc-exposed group. The SMR (observed cases = 24, expected cases = 18.69) was calculated based on the workers ever highly exposed to talc. For the workers ever exposed to talc, the number of observed cases was 104, and the number of expected cases was 113.16. These supplementary data were obtained by email contacts to the authors [11]. The SMR of lung cancer was calculated based on the workers exposed to nonfibrous talc, but the SMR of all-cause mortality was only available for the total cohort. The overall scores of NOS were categorized into three levels: high (8-9 stars), medium (6-7 stars), and low quality (1–5 stars).