Understanding breast cancer risk in Chinese populations

Obesity has long been associated with an increased risk of breast cancer in post-menopausal women. But the relationship between obesity and breast cancer is less clear in pre-menopausal women. Moreover, a lot of uncertainty remains around the associations between body weight and breast cancer in countries such as China, where the average BMI is lower than in western countries, along with differences in the prevalence of other risk factors between western and eastern cultures. There is a need to better understand how morphological and lifestyle differences between populations may influence cancer incidence, in order to better understand and identify who is at an increased risk.

An upcoming study from the Clinical Trial Service & Epidemiological Studies Unit (CTSU) at the Nuffield Department of Population Health, led by Dr Christiana Kartsonaki and Dr Ling Yang, is investigating breast cancer incidence in Chinese populations in relation to adiposity measures such as BMI, waist circumference and body fat percentage.

The team used data from the China Kadoorie Biobank, a cohort study that has collected information from over half a million individuals from China since 2004. During an average of 10 years of follow-up of this cohort, there were 2,053 cases of breast cancer, which allows the team to assess what demographic or lifestyle factors might be influencing risk in Chinese women.

Early results suggest that, like western populations, increased levels of adipose tissue leading to higher BMIs are associated with higher risks of breast cancer in Chinese women, particularly among post-menopausal women. These results highlight the importance of understanding relative cancer risk factors between different ethnicities. Whilst some factors such as obesity are often common causes of cancer across all populations, there are many key biological and lifestyle factors that differ between western and eastern populations. Understanding how these may impact cancer risk in different ways will allow researchers to inform policy, so that clinicians may better identify who may have a higher risk of developing cancer.

About the CTSU

The Clinical Trial Service Unit and Epidemiological Studies Unit (CTSU) aims to generate and disseminate reliable evidence from observational epidemiology and from randomised trials that leads to practicable methods of avoiding premature death and disability.

This project is being led by Dr Christiana Kartsonaki and Dr Ling Yang in conjunction with Prof. Zhengming Chen.