Brief background

The Million Women Study (MWS) is a UK national observational study of women's health, involving around one million women aged 50 and over, presenting for breast screening. It aims to answer many outstanding questions about the factors affecting women's health in this age group. The main focus of the study relates to the effects of hormone replacement therapy use. Conclusions drawn from the study's findings must be viewed cautiously because of how the women were recruited to the study and the potential for bias and confounding.

The study is investigating how various reproductive and lifestyle factors affect women's health. In particular, the study is looking at how hormone replacement therapy affects a woman's breasts and other aspects of her health. Other factors being investigated include diet, childbirth, breastfeeding, vitamin and mineral supplement use, oral contraceptive use and family history of illness. More than one in four women in the UK in the target age group are now participating in the study it is the largest study of its kind in the world.

Funds for The Million Women Study have been provided by Cancer Research UK, the UK National Health Service Breast Screening Programme and the UK Medical Research Council.

The Million Women Study (www.millionwomenstudy.org)

Expert comment on The Million Women Study results

The Jean Hailes Foundation for Women's Health provides expert comment from the Australian perspective.

Hormone therapy

There are different ways of taking HT and different combinations of the three hormones; oestrogen, progesterone and testosterone. HT can be prescribed as tablets, patches, skin gel, implants, oestrogen injections, vaginal preparations such as creams, tablets or pessaries (suppositories) or ring for local application inside the vagina. 

The tablets are taken orally on a daily basis. The patch is applied to the skin on the lower body once or twice weekly, the gel is applied daily and the implant (hormone pellet) is inserted under local anaesthetic beneath the skin and usually lasts four to six months. In all the non-oral routes the hormones are absorbed directly into the bloodstream whereas with tablets they are absorbed through the intestine first.

For more information go to Hormones

Content updated 20 June, 2008