Does diet and shift work increase the risk of breast cancer
Tuesday 6 February 2018

Eating sausages, bacon and other processed meat is linked to an increased risk of breast cancer in post-menopausal women, a large-scale study has found. Separately, research has confirmed that night shift work is linked to a pronounced increased risk of breast cancer, particularly for nurses.

Processed meat

Although the link between processed meat and some cancers is already well documented, this study focused in particular on the potential link between red or processed meat and breast cancer.

Processed meats are defined as meats with added preservatives and/or those that have been salted, cured, fermented or smoked. This includes ham, bacon, sausages and some deli meats.

The study

Between 2007 and 2010, the study recruited 262,195 women based in the UK, aged between 40 and 69 years old. All participants were free of cancer when recruited. Of the participants, 4,819 went on to develop breast cancer during a seven-year follow-up period.

In those who ate the most processed meat (over nine grams per day), the risk of developing breast cancer was found to be 21% higher than those who ate no processed meat.

The study also combined its results with 10 previously published studies, covering over 1.6 million women in total. The combined results found that post-menopausal women who ate processed meat had a 9% higher chance of developing breast cancer than women who ate no processed meat.

In pre-menopausal women, it found no association between eating processed meat and breast cancer risk; and, for women at any stage, the combined study found that eating red meat did not increase the risk of developing breast cancer.

It is important to note that although the study reported the increased risk for post-menopausal women, it could not verify that consuming processed meat directly caused the breast cancer. However, the NHS advises that ‘restricting your intake to an occasional treat, rather than eating processed meat every day, may benefit your health in other ways’.

Shift work and breast cancer

Continuing the focus on breast cancer risk and lifestyle, new research has confirmed a strong link between long-term night shift work and an increased overall risk for cancer in women, particularly breast cancer.

The analysis combined data from over 60 studies, covering nearly 4 million women with cancers of the breast, lung, skin, and digestive and reproductive systems. It examined the link between long-term night shift work and the risk for 11 types of cancer.

Across Europe, North America, Australia and Asia, the overall risk for cancer increased by 19% among women working night shifts, compared with those who did not.

In Europe and North America only, the review found that working night shifts was associated with a 32% increased breast cancer risk. A drill down of the data found that the risk was even higher for nurses who work the night shift; this group was reported to have a ‘remarkable’ 58% increased risk for breast cancer.

The fact that this association was only in Europe and North America surprised the researchers. Lead author Xuelei Ma Chengdu, from the West China Medical Center of Sichuan University, said: “It is possible that women in these locations have higher sex hormone levels, which have been positively associated with hormone-related cancers such as breast cancer”.

He explaining that breast cancer is the most diagnosed cancer among women worldwide, with higher incidence in developed regions. He said that more large-scale studies should be conducted to confirm the associations, and that new research is needed to explain the association and to better protect women working night shifts against increased cancer risk.

If you would like to speak with a consultant regarding breast cancer please call 01883 348 981.

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