This is one of two linked papers in The BMJ that shed new light on the relation of alcohol and diet with the two commonest diseases in women in western countries: breast cancer and ischaemic heart disease.
According to an editorial notes, the results for breast cancer are in line with previous research, and the authors argue that the association with changes in alcohol intake provides stronger evidence that the relation is causal. It adds that for ischaemic heart disease, the apparent benefit in women who reported an increase in alcohol consumption is still potentially biased if women with poor health are under-represented in this group. With regards to public health, it is noted that alcohol is responsible for about 11% of female breast cancers in the UK, but it is still not known whether a decrease in alcohol intake in middle age leads to a subsequent reduction in breast cancer risk, whilst the true effect of alcohol on risk of ischaemic heart disease remains uncertain.