The study also found that Black women are diagnosed younger than white women, with more than 50 per cent of breast cancer cases in Black women diagnosed before the age of 50, compared to about 14 per cent in white women.

Black women are also more likely to be diagnosed with more aggressive subtypes, like triple-negative breast cancer, that don’t respond to certain treatment, the researchers found.

They face up to 21 per cent higher rates of triple-negative breast cancer, compared to about 9.9 per cent for white women.

I wonder what causes this. Genetics? Lifestyle? Both? Neither?

Edit: the paper pretty much gives the answer in the abstract

Breast cancer characteristics and outcomes vary substantially by ancestry within Canada’s Black population.