Study examines why overweight women are less likely to undergo breast cancer screening

Obese women may be putting themselves at greater risk of breast cancer by not undergoing regular screening.

According to new research by Dr. Nisa Maruthur and her team from The John Hopkins University School of Medicine in Baltimore, USA, seriously obese women are significantly less likely to say they have undergone a recent mammography than normal weight women, especially if they are white. Maruthur's findings are published online this week in Springer's Journal of General Internal Medicine.

Breast cancer is the second leading cause of cancer death among women in the US. Mammography screening has been proven to reduce the number of deaths from breast cancer; current guidelines recommend that women over the age of 40 undergo a mammography every couple of years. Obesity is also an important risk factor for both the development of, and death from, postmenopausal breast cancer.

Maruthur and colleagues conducted a systematic review and meta-analysis of 17 studies comprising over 276,000 participants, to look at whether overweight and obese women are less likely to have had a recent mammography than normal weight women. They also looked at the differences in mammography take-up between white and black obese women in three of the studies. They found that severely obese women were 20 percent less likely to have had a recent mammography than normal weight women. However, this was not the case among black women.

The authors highlight a number of reasons why obese women may not be undergoing breast cancer screening, including a delay in taking up medical care because of poor self-esteem and body image, embarrassment, a perceived lack of respect from their health care providers and unwanted weight loss advice. According to the authors, obesity may be a marker for sub-optimal health behavior in general, of which mammography is simply one element. The authors also suggest that there are racial differences in obesity-related body image which may explain the difference in take-up of mammography between white and black women.

The authors conclude that "the main implication of our study is that a lack of routine screening mammography may explain some of the increased breast cancer mortality in obese postmenopausal women. Clinicians should be aware of this disparity in evaluating their own practices."

Full bibliographic information: Maruthur NM et al (2009). Obesity and mammography: a systematic review and meta-analysis. Journal of General Internal Medicine, DOI 10.1007/s11606-009-0939-3