The questionnaire

The questionnaire asks about various factors in a woman’s life that might be connected with risk of breast cancer. These include factors known to be associated with breast cancer, some suspected, and some that are included because they are frequently asked about by women, and give rise to anxiety without a proven scientific basis.

The questions asked include, for instance, how many children a woman has had, what age she was at their births, and whether she has had breast disease – factors known to relate to breast cancer risk.

Questions are also asked, for instance, about night work and sleeping patterns, for which it is uncertain whether or not there is a relation to breast cancer. These questions relate to a theory first put forward 20 years ago, that breast cancer risk might be affected by a hormone called melatonin that the body secretes at night when it is dark. The hormone is known to be responsible for maintaining our 24 hour rhythm of sleep and wakefulness, and for the feelings of jet lag, but it is unknown, despite theories that have been put forward, whether it has any effect on breast cancer risk or not. We therefore ask about various factors that might influence melatonin levels – including shiftwork, light exposure at night, and sleeping patterns – so that in years to come we will be able to determine whether or not these factors affect breast cancer risk.