The follow-up period in the new study was relatively short, they say, and breast-cancer diagnosis and treatment may be different in China compared to the United States.

CNN: Soy may benefit breast cancer survivors, study says

Professor Calder acknowledged that the patients involved in the study took relatively high doses of omega-3 oil.

BBC: Fish oils 'keep arteries clear'

"Our treatment of heart failure is, in this day and age, relatively non-specific, " said Christine Seidman who led the study.

BBC: Gene link to inherited heart disease

Men and women infected with HIV reduced the risk of transmitting the virus to their sexual partners by taking oral antiretroviral medicines when their immune systems were relatively healthy, according to findings from a large-scale clinical study sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.

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The study compared a relatively small number of women who had undergone the procedure - called oopherectomy - with those who had not.

BBC: Cancer op 'may not cure worries'