Table 6 Pooled estimates on the relative risk (RR) of leukaemia incidence within 5 km of a petrochemical facility, moderated by different characteristics
Assessment | Characteristics | Heterogeneity Tests | Pooled Relative Risks (95% CI) | ||
|---|---|---|---|---|---|
I2 (%) | QE (p-value) c | QM (p-value) c | |||
Base Model | – | 52.18 | 0.01 | – | – |
Demographic | 1.1. Gender   • All (n = 5)   • Male (n = 5)   • Female (n = 3) | 47.98 | 0.03 | 0.67 | – |
1.2. Participants   • Children (n = 2)   • General Population (n = 11) | 57.63 | 0.01 | 0.51 | – | |
Diagnosis | 2.1. Classification Scheme   • ICD 7–10 (n = 8)   • ICD for Oncology (n = 5) | 49.48 | 0.02 | 0.37 | – |
2.2. Classification Scheme   • ICD 7–8 (n = 3)   • ICD 9–10 (n = 5)   • ICD for Oncology (n = 5) | 56.71 | 0.02 | 0.73 | – | |
Exposure | 3.1. Petrochemical Sector   • Upstream (n = 7)   • Downstream (n = 3)   • Combination (n = 3) | 52.99 | 0.02 | 0.85 | – |
3.2. Maximum Distance   • 3 km (n = 10)   • 3.1 to 5 km (n = 3) | 41.98 | 0.05 | 0.12 | – | |
Geography | 4. Continent   • Europe (n = 8)   • North America (n = 4)   • Asia (n = 1) | 31.67 | 0.09 | 0.24 | – |
Quality d | 5.1. Newcastle-Ottawa Score   • Low (n = 4)   • High (n = 9) | 45.10 | 0.04 | 0.07 | – |
5.1.1. Participant Selection   • Low (n = 4)   • High (n = 9) | <  0.01 | 0.60 | <  0.01 | Low: 1.01 [0.90 to 1.14] High: 1.58 [1.32 to 1.90] | |
5.1.2. Study Comparability   • Low (n = 7)   • High (n = 6) | 45.07 | 0.04 | 0.20 | – | |
5.1.3. Outcome Assessment   • Low (n = 5)   • High (n = 8) | 33.38 | 0.12 | 0.03 | Low: 1.71 [1.25 to 2.35] High: 1.15 [0.98 to 1.37] | |
Temporal | 6.1. Study Start   • 1965 to 1974 (n = 3)   • 1975 to 1984 (n = 3)   • 1985 to 1994 (n = 2)   • 1995 to 2004 (n = 5) | <  0.01 | 0.42 | <  0.01 | 1965/74: 1.02 [0.91 to 1.15] 1975/84: 1.21 [1.09 to 1.34] 1985/94: 1.43 [1.23 to 1.65] 1995/04: 1.69 [1.36 to 2.11] 2005/14: 2.00 [1.48 to 2.70] b |
6.2. Study Start (+ 1 Year) a | <  0.01 | 0.28 | <  0.01 | 1971: 1.00 [0.88 to 1.14] 1981: 1.20 [1.09 to 1.33] 1991: 1.44 [1.23 to 1.69] 2001: 1.73 [1.36 to 2.22] 2011: 2.08 [1.48 to 2.93] b | |
Mixed Effect | 5.1.1. Participant Selection, and 6.2 Study Start (+ 1 Year) a | <  0.01 | 0.63 | <  0.01 | 1971: 1.38 [1.02 to 1.87] 1981: 1.49 [1.21 to 1.84] 1991: 1.61 [1.34 to 1.93] 2001: 1.74 [1.36 to 2.22] 2011: 1.88 [1.32 to 2.67] b |