Organic food consumption and the incidence of cancer in a large prospective study of women in the United Kingdom

Abstract

Background: Organically produced foods are less likely than conventionally produced foods to contain pesticide residues.

Methods: We examined the hypothesis that eating organic food may reduce the risk of soft tissue sarcoma, breast cancer, non-Hodgkin lymphoma and other common cancers in a large prospective study of 623 080 middle-aged UK women. Women reported their consumption of organic food and were followed for cancer incidence over the next 9.3 years. Cox regression models were used to estimate adjusted relative risks for cancer incidence by the reported frequency of consumption of organic foods.

Results: At baseline, 30%, 63% and 7% of women reported never, sometimes, or usually/always eating organic food, respectively. Consumption of organic food was not associated with a reduction in the incidence of all cancer (n=53 769 cases in total) (RR for usually/always vs never=1.03, 95% confidence interval (CI): 0.99-1.07), soft tissue sarcoma (RR=1.37, 95% CI: 0.82-2.27), or breast cancer (RR=1.09, 95% CI: 1.02-1.15), but was associated for non-Hodgkin lymphoma (RR=0.79, 95% CI: 0.65-0.96).

Conclusions: In this large prospective study there was little or no decrease in the incidence of cancer associated with consumption of organic food, except possibly for non-Hodgkin lymphoma.

Figure 1

Percentage of women who reported usually/always eating organic food, by region of recruitment (boundaries are approximate). Screening centres in Wales were not involved in this study. Base map OpenStreetMap.org contributors. Contains Ordnance Survey data Crown Copyright and database right 2014.

Figure 2

Relative risk of cancer incidence for 16 individual cancer sites and total cancer by reported organic food consumption. Stratified by age, region, and deprivation, and adjusted for smoking, BMI, physical activity, alcohol intake, height, parity and age at first birth, fibre intake, and type of meat eaten. *g-s CI: group-specific confidence intervals.

Figure 3

Relative risk of non-Hodgkin lymphoma for usually or always vs never consumers of organic food by sub-groups of characteristics. Stratified by age, region, deprivation, and adjusted for smoking, BMI, physical activity, alcohol intake, height, parity and age at first birth, fibre intake (except for analysis stratified by fruit and vegetable consumption), and type of meat eaten.