Body mass index, agricultural pesticide use, and cancer incidence in the Agricultural Health Study cohort

Abstract

Obesity is associated with increased risks of several cancers including, colon, lower esophagus, kidney, female breast, and endometrium. Some studies have associated pesticides with higher risks of cancer in agricultural populations. The interaction between obesity and pesticide use on cancer risk has not been well studied. Using data from the Agricultural Health Study we examined the association between body mass index (BMI) and the risk of cancer at 17 sites, and the interaction between BMI and pesticide use. Pesticide applicators (primarly farmers), and their spouses residing in Iowa and North Carolina were enrolled between 1993 and 1997 and followed through 2005. This analysis included 39,628 men and 28,319 women who provided information on pesticide use, height and weight data, and were cancer-free at enrollment. Of all subjects, 64% were overweight or obese, and 4,432 incident cancers were diagnosed during the follow-up period. We found positive associations between BMI (continuous) and colon cancer among men (Hazard Ratio (HR) 1.05, 95% confidence interval (CI) 1.02-1.09) and breast cancer among postmenopausal women (HR 1.03, 95% CI 1.01-1.06), as well as an inverse association with lung cancer among men who were ever smokers (HR 0.92, 95% CI 0.88-0.96). Men who ever used carbofuran (HR=1.10, 95% CI 1.04-1.17), metolachlor (HR=1.09, 95% CI 1.04-1.15), and alachlor (HR=1.08, 95% CI 1.03-1.13) had significant positive associations between BMI and colon cancer, but non-users did not. Men who ever smoked and used carbofuran had a positive, although not significant, association between BMI and lung cancer, while users of carbofuran had a significant inverse association. These findings, which suggest that certain pesticides may modify the association between BMI and colon and lung cancer risk, should be further evaluated in other populations.

Socio-demographic and behavioural determinants of body mass index among an adult population in rural Northern Ghana: the AWI-Gen study

“…Cross-sectional [24,26,27,63] and longitudinal [23,25] studies have reported similar findings. This observation in our population is of great concern and a potential driver for obesity in this population due to the high exposure to pesticides.…”

“…Pesticides contain chemical compounds that are widely considered as obesogenic and endocrine disruptors. These compounds are reported to modulate lipid metabolism, hormone and neurotransmitter levels and adipogenesis and thus cause weight gain [23–27,63]. …”

“…The role of genetic factors in determining BMI has also been extensively reported in the literature [21,22]. Several cross-sectional and longitudinal studies in non-African countries have also observed a positive association between BMI and pesticide exposure [23–27]. However, this observation has not been previously reported in literature from SSA.…”

Body mass index, abdominal fatness and pancreatic cancer risk: a systematic review and non-linear dose–response meta-analysis of prospective studies

“…Abdominal obesity may be more strongly associated with insulin resistance than peripheral obesity (4), but there have been relatively few studies of waist circumference and waist-to-hip ratio as measures of abdominal fatness in relation to pancreatic cancer risk. A number of additional large cohort studies have been published since the WCRF/AICR report from 2007 (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17), thus, we conducted an updated meta-analysis of BMI, waist circumference and waist-to-hip ratio and pancreatic cancer risk with the aim to clarify whether body fatness is associated with pancreatic cancer in both men and women and in European and Asian populations as well. In addition, we wanted to clarify the dose-response relationship between BMI, waist circumference and waist-to-hip ratio and pancreatic cancer risk by conducting nonlinear dose-response analyses and by restricting the analysis to studies among non smokers or never smokers.…”

Comments on a recent meta‐analysis: Obesity and lung cancer

“…2), where study-specific risk estimates and their CIs are plotted, also indicates a heterogeneous set of studies. In particular, heterogeneity could be attributed to six cohort [2][3][4][5][6][7] and five case-control [8][9][10][11][12] studies. It would have been informative to identify which aspects of the individual studies contributed to heterogeneity.…”