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Table 3 Results of meta-regression analyses

From: Occupational exposure to silica dust and risk of lung cancer: an updated meta-analysis of epidemiological studies

Measure Parameter k Estimate P value estimate P value of Q I2 R2 p covariates
Meta-regression analysis of SMR studies
 SMR No covariate 63 1.55 (1.38–1.75) <0.0001 <0.0001 96.18   
 Univariate model Year of publication 63 2.30E + 18 (2.41E + 08–2.19E + 28) 0.003 <0.0001 95.44 15.12 0.000
Industry 63 1.15 (0.86–1.53) 0.353 <0.0001 95.71 8.15 0.027
Person-years of follow-up 22 1.53 (1.25–1.87) <0.0001 <0.0001 94.73 13.4 0.050
NOS score 63 3.53 (2.27–5.49) <0.0001 <0.0001 95.11 19.18 0.000
Number of subjects 63 1.69 (1.48–1.92) <0.0001 <0.0001 95.43 10.89 0.008
Total number of deaths 54 1.69 (1.48–1.94) <0.0001 <0.0001 95.31 13.94 0.006
 Multivariate model Industry, year of publication 63 1.07E + 19 (3.85E + 09-2.97E + 28) <0.0001 <0.0001 94.65 25.51 <0.0001
Industry, year of publication, geographical location 63 1.04E + 20 (4.90E + 10-2.21E + 29) <0.0001 <0.0001 94.3 28.85 <0.0001
Industry, year of publication, geographical location, number of subjects 63 1.80E + 17 (1.67E + 08-1.94E + 26) <0.0001 <0.0001 93.18 37.41 <0.0001
Industry, year of publication, geographical location, number of subjects, NOS score 63 1.06E + 16 (5.27E + 06-2.12E + 25) 0.001 <0.0001 93.05 37.04 <0.0001
Industry, year of publication, geographical location, number of subjects, total deaths 54 5.32E + 18 (1.07E + 08-2.65E + 29) 0.001 <0.0001 92.72 34.76 <0.0001
Industry, year of publication, geographical location, NOS score 63 1.29E + 17 (3.61E + 07-4.61E + 26) <0.0001 <0.0001 93.77 32.23 <0.0001
Person-years of follow-up, industry 22 1.22 (0.76–1.96) 0.408 <0.0001 94.12 13.87 0.086
Person-years of follow-up, industry, year of publication 22 2.80E + 14 (2.88E-08-2.73E + 36) 0.198 <0.0001 92.81 17.99 0.079
Person-years of follow-up, industry, year of publication, geographical location 22 1.55E + 23 (4.66E-02-5.12E + 47) 0.064 <0.0001 92.31 23.08 0.056
Person-years of follow-up, number of subjects 22 1.62 (1.31–2.00) <0.0001 <0.0001 92.9 17.36 0.055
Meta-regression analysis of SIR studies
 SIR No covariate 19 1.68 (1.45–1.96) <0.0001 <0.0001 74.51   
 Univariate model Year of publication 19 7.92E + 11 (3.71E-02-1.69E + 25) 0.080 <0.0001 72.31 4.27 0.086
Industry 19 1.37 (0.97–1.95) 0.077 <0.0001 70.88 11.68 0.214
Number of subjects 19 1.88 (1.55–2.28) <0.0001 <0.0001 69.94 18.16 0.086
Total number of deaths 5 1.29 (1.05–1.59) 0.017 0.687 0 100 0.017
 Multivariate model Number of subjects, exposure level 19 2.09 (1.47–2.96) <0.0001 <0.0001 72.12 9.02 0.197
  Number of subjects, NOS score 19 3.01 (1.52–5.95) 0.002 <0.0001 69.36 15.16 0.087
  Number of subjects, industry 19 1.71 (1.03–2.85) 0.037 <0.0001 70.28 10.84 0.229
Meta- regression of silicotic studies
 SMR Year of publication 24 7.03E + 21 (5.05E + 04-9.79E + 38) 0.013 <0.0001 92.23 20.55 0.014
Year of publication, total number of deaths 20 1.59E + 23 (1.60E + 05-1.57E + 41) 0.012 <0.0001 86.98 42.87 0.002
Year of publication, total number of deaths, geographical location, industry 20 4.61E + 22 (2.40E + 03-8.85E + 41) 0.021 <0.0001 86.9 33.84 0.022
Year of publication, total number of deaths, industry 20 6.07E + 22 (1.43E + 04-2.58E + 41) 0.017 <0.0001 87.46 38.8 0.002
Year of publication, total number of deaths, geographical location 20 9.89E + 22 (2.24E + 04-4.37E + 41) 0.016 <0.0001 86.65 38.3 0.007
Year of publication, geographical location 24 1.26E + 22 (3.90E + 04-4.08E + 39) 0.013 <0.0001 92.05 16.98 0.050
  1. k number of studies, Q chi-square test for heterogeneity, I 2 variability due to heterogeneity, R 2 amount of heterogeneity accounted for, SMR standardized mortality ratio, SIR standardized incidence ratio, NOS Newcastle-Ottawa scale