A study led by Oxford University researchers, shows that taller women are more likely to develop ovarian cancer. Their work is part of a large worldwide study published in the journal PLoS Medicine this week and aims to define the factors which may cause the development of ovarian cancer.
Scientists from the Cancer Epidemiology Unit at Oxford, headed up the international collaborative group, processed data from 47 epidemiological studies including over 25,000 women with ovarian cancer and more than 80,000 women without. These studies, both published and unpublished, provide virtually all the relevant data on the topic worldwide.
In summary, there appeared to be a 7% increased risk in developing ovarian cancer with each 5cm increase in a woman’s height. Thus a woman 170cm tall, had a 14% greater risk than one 160cm tall.
Dr Gillian Reeves of the Cancer Epidemiology Unit at Oxford University, one of the lead researchers on the study clarified that :
“The fact that height is clearly associated with risk may well be important for understanding how ovarian cancer develops. … Although we do not yet know why height is related to ovarian cancer risk, there are a number of possible explanations. For example, the association that we see may be due to the biological effects of factors associated with height – such as increased levels of insulin like growth factor (IGF-1) (which has been associated with a number of other cancers such as breast and prostate cancer), or increased numbers of cells being at risk of becoming cancerous. Future studies should clarify this.”
The scientists also looked at body mass index (BMI), a ratio of weight by the square of height, that provides a ratio defining level of obesity. Women who have never used HRT showed a 10% increase in relative risk of ovarian cancer for every 5 kg/m2 rise in BMI, but the relationship was not present in those who had used HRT.
Dr Reeves said:
“These results show that in women who are not taking HRT, ovarian cancer risk increases steadily with increasing BMI. These results relate only to the effect of body size on ovarian cancer risk and do not provide any relevant information about advice on HRT use.”
While the focus of the study was looking for biological factors connected to ovarian cancer, the BMI information is useful because it’s something a person could potentially do something about by losing weight. It is thought that estrogen levels in post menopausal women are affected by the level of body fat in women who don’t use HRT.
The average height and BMI in western countries is slowly increasing, which in theory means that if all other factors remain constant, ovarian cancer cases would increase by 3% per decade. Sarah Williams, health information officer at Cancer Research UK, which funded the work, said:
“This study included as much evidence as possible to produce a clearer picture of the factors that can affect a woman’s risk of developing ovarian cancer, and found that body size was important. Women can reduce their risk of this and many other diseases by keeping to a healthy weight. For women trying to lose weight, the best method is to eat healthily, eat smaller amounts and be more physically active.”
Written by Rupert Shepherd