LB61
Cancer incidence in British vegetarians
Tim Key1, Paul Appleby1, Elizabeth Spencer1, Ruth Travis1, Naomi Allen1, Margaret Thorogood2, Jim Mann3
1Oxford University, UK; 2Warwick University, Coventry, UK; 3University of Otago, Dunedin, New Zealand
Background
Little is known about cancer incidence among vegetarians.
Method
We studied 61,566 British men and women, comprising 32,403 meat-eaters,
8,562 non meat-eaters who did eat fish (fish-eaters) and 20,601
vegetarians. After an average follow-up of 12.2 years there were 3,350
incident cancers: 2,204 among meat-eaters, 317 among fish-eaters and 829 among
vegetarians. Relative risks (RRs) were estimated by Cox regression,
stratified by sex and recruitment protocol and adjusted for age, smoking, alcohol,
body mass index, physical activity level and, for women only, parity and oral
contraceptive use.
Results
There was significant heterogeneity in cancer risk between groups for four
cancer sites: stomach cancer, RRs compared to meat-eaters of 0.29 (95% CI 0.07-1.20)
in fish-eaters and 0.36 (0.16-0.78) in vegetarians, P for
heterogeneity=0.007; ovarian cancer, RRs 0.37 (0.18-0.77) in fish-eaters and
0.69 (0.45-1.07) in vegetarians, P for heterogeneity=0.007; bladder
cancer, RRs 0.81 (0.36-1.81) in fish-eaters and 0.47 (0.25-0.89) in
vegetarians, P for heterogeneity=0.05; and cancers of the lymphatic and
haematopoietic tissues, RRs 0.85 (0.56-1.29) in fish-eaters and 0.55
(0.39-0.78) in vegetarians, P for heterogeneity=0.002. The RRs for
all malignant neoplasms were 0.82 (0.73-0.93) in fish-eaters and 0.88
(0.81-0.96) in vegetarians, P for heterogeneity=0.001.
Conclusion
The incidence of some cancers may be lower in fish-eaters and vegetarians
than in meat-eaters.
