Sex differences in cancer incidence: prospective analyses in the UK Biobank.

BACKGROUND

We examined differences in cancer incidence between women and men and the extent to which these persisted after accounting for established risk factors.

METHODS

Prospective analyses in the UK Biobank to examine associations between sex and risk of 15 cancers (and 13 subtypes) using minimal and multivariable-adjusted Cox proportional hazards regression models. Multivariable models were stratified for age, deprivation index, and region, and adjusted for ethnicity, qualifications, height, BMI, smoking status, alcohol, and site-specific risk factors.

RESULTS

During 10.5 (SD 2.2) years of follow-up, 32,315 incident cancers across 15 anatomical sites (58.1% in women) were identified in 470,771 individuals (53.8% women). Some differences in cancer risk between the sexes attenuated to the null in the multivariable-adjusted models, but men remained at greater risk than women for cancers at eight sites: oesophageal adenocarcinoma (hazard ratio 5.45; 95% confidence interval, 4.18-7.12), gastric cardia (3.65; 2.48-5.38), bladder (3.47; 2.85-4.24), oral cavity (2.06; 1.69-2.51), liver (1.91; 1.48-2.47), kidney (1.77; 1.51-2.09), rectum (1.70; 1.47-1.96), and leukaemia (1.43; 1.21-1.69). Men had lower risks for cancers of the breast, thyroid (0.36; 0.26-0.49), anus (0.41; 0.26-0.64), and lung adenocarcinoma (0.72; 0.62-0.84).

CONCLUSION

Further research on these sex differences in risk may provide insights into cancer aetiology.