Table 2

Pooled risk estimates for non-Hodgkin’s lymphoma by exposure assessment method, study design, publication year period and geographic region, based on meta-analysis of articles on occupational pesticide exposure published between 1987 and 2017.

Number of risk estimatessRR95% CIHeterogeneity measures
I2 (%)P valueQP value
Exposure assessment method6.230.07
Group-level171.211.05 to 1.4063<0.01
Self-reported exposure131.491.16 to 1.9176<0.01
Expert-level101.741.39 to 2.1900.68
Study design22.1<0.01
81.040.96 to 1.13230.24
41.110.89 to 1.39110.34
Case–control281.661.39 to 1.9857<0.01
Publication year period
1987–2005191.151.00 to 1.32210.28.5<0.01
2006–2017211.591.34 to 1.8778<0.01
Geographic region3.890.14
Europe181.421.13 to 1.7755<0.01
North America181.271.10 to 1.4770<0.01
Other41.771.31 to 2.39380.18
Case–control studies only
Exposure assessment method0.10.95
Group-level91.631.20 to 2.2161<0.01
Self-reported exposure111.671.21 to 2.3171<0.01
Expert-level81.731.33 to 2.2700.47
Exposure assessment method during publication year periods
Exposure assessment method2.300.32
Group-level81.040.83 to 1.28310.18
Self-reported exposure81.261.05 to 1.5100.51
Expert-level31.370.86 to 2.1700.51
Exposure assessment method4.680.1
Group-level91.351.11 to 1.6474<0.01
Self-reported exposure51.941.14 to 3.3091<0.01
Expert-level71.881.45 to 2.2400.7
  • I2=percentage of variation across studies due to heterogeneity. Q=Cochran’s Q.

  • sRR, summary risk ratio.