Introduction Agricultural work can expose workers to potentially hazardous agents including known and suspected carcinogens.

Objectives We aimed to evaluate the cancer incidence in agricultural cohorts in an international consortium, AGRICOH, relative to the respective general populations.

Methods For 24 cancer sites/types and all cancers combined, we estimated standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) in eight cohorts that were linked to respective cancer registries: France (AGRICAN: n=128,101), the United States (AHS: n=51,165, MESA: n=2,177), Norway (CNAP: n=43,834), Australia (2 cohorts combined, Australian Pesticide Exposed Workers and Victorian Grain Farmers: n=13,134), Republic of Korea (KMCC: n=8,432), and Denmark (SUS: n=1,899). We then combined the SIR estimates across cohorts by random-effects meta-analysis.

Results During nearly 2,800,000 person-years, 23,188 cancers were diagnosed. We observed an elevated risk for melanoma of the skin (number of cohorts included=3, meta-SIR=1.18, 95% CI: 1.01–1.38) and multiple myeloma in women (n=4, meta-SIR=1.27, 95% CI: 1.04–1.54) and prostate cancer (n=6, meta-SIR=1.06, 95% CI: 1.01–1.12) compared to the general population. For several cancer sites, including bladder, breast (female), colorectum, esophagus, larynx, lung, and pancreas and all cancers combined, the risk was lower in the agricultural cohorts than in the general population (n=7, sex-adjusted meta-SIR for all cancers combined=0.83, 95% CI: 0.77–0.90). The direction of risk was mostly consistent across cohorts while for some cancer sites, such as liver and lung in men and women, and stomach, colorectum, and skin in men, the SIR varied greatly across cohorts.

Conclusion Our findings suggest that agricultural workers have a lower risk of various cancers and an elevated risk for prostate cancer, multiple myeloma (female), and melanoma of skin (female) compared to the general population. The observed excesses and deficits of cancer incidence in agricultural workers may be largely due to underlying differences in risk factors and warrant further investigation of specific agricultural exposures.