Jump to comment:
- Please do not forget the lack of physical activity
Dear Editor,
I congratulate Ms. Volesky and Dr. Villeneuve for their very interesting article “Examining screening mammography participation among women aged 40 to 74” in the June 2017 issue of the Canadian Family Physician [1]. The authors wrote: “Modifiable factors associated with breast cancer include alcohol consumption, smoking, hormone replacement therapy, and postmenopausal obesity.” These factors mentioned were included, among others, in the data analysis. There is one important modifiable lifestyle aspect worth mentioning.
Moderate levels of physical activity can reduce breast cancer risk, which has been observed 30 years ago [2-4]. Today, convincing evidence exists for this association. Several recent meta-analyzes show that physically active women have a 12-25% lower risk of breast cancer compared to the least active women [5-8]. This risk reduction also applies to household physical activity (relative risk 0.78 (95% confidence interval (CI) 0.69-0.89)) [9]. There is generally a clear dose-response relationship between physical activity and breast cancer risk [7]. In the above citation, the authors refer to references (e.g. Colditz et al. CA Cancer J Clin. 2014;64(3):186-94), which also call "lack of physical activity" as one of the established modifiable causes of breast cancer.
The authors have included the study by Maxwell et al. in their references, but unfortunately it was not mentioned that this Canadian study examined infreq...
Show MoreCompeting Interests: None declared. - RE: Examining screening mammography participation among women aged 40 to 74
The authors correctly point out some of the limitations of this study related to the use of self report data, however, breast screening programs in Canada are offered in every jurisdiction as public health programs. Indeed objective data are collected by each of these programs.
Of greater concern is the failure of the authors to analyze the findings adequately by age group. They fail to differentiate between women less than 50 where screening is not recommended in Canada and those in the older age groups. In addition they misinterpret their own findings: "...factors related to health care use exerted a stronger effect. Having a regular doctor, a physical checkup in the past year, and a Pap test in the past 3 years were strongly related to whether women aged 40 to 74 participated in screening mammography in 2012." This language suggests a causal relationship between the associated factors and screening mammography. In particular "exerting a stronger effect" is clearly an unfounded statement. The study does not support this causal relationship. Indeed with the current state of knowledge of mammography screening it would not be surprising if rates of screening were lower in women who had meaningful discussions with their family doctors(1).
Reference
1.Katz A. Family doctors should engage with patients about mammography. Eur J Cancer Care. 2017;26:e12701. https://doi.org/10.1111/ecc.12701...
Show MoreCompeting Interests: None declared.