Night shift link to breast cancer

A new study has linked working night shifts with the development of breast cancer

Two out of five women working night shifts have an increased risk of developing breast canc,r according to research from Denmark.

The findings indicated that working up to two night shifts a week had no impact on the risk of developing breast cancer, As this may not be long enough to disrupt the body clock, say the authors from the Institute of Cancer Epidemiology, Danish Cancer Society, Denmark.

On the other hand, frequent night shifts for several years may disrupt the body clock and normal sleep patterns., The researchers suggest this may inhibit the production of the cancer-protecting hormone melatonin, they suggest.

Researchers assessed many factors in the women's lives such as contraception, sun bathing habits and whether they would call themselves a 'morning' or 'evening' person.

The researchers contacted 210 women who had had breast cancer between 1990 and 2003, and were still alive in 2005/2006. These women were then matched with 899 women without breast cancer,

The results, based on 692 responses,141 from women with breast czncer, indicated that women who worked more than twice a week on night shift had a 40% increased risk of breast cancer, compared with women who worked no night shifts, the researchers said.

The study is published online in Occupational and Environmental Medicine.

[Posted: Wed 30/05/2012]