Women who gain weight in midlife may have an increased risk of developing postmenopausal breast cancer, according to research findings presented at the 2010 Annual Meeting of the American Association for Cancer Research.
Research into lifestyle factors that influence breast cancer risk or prognosis allows us to make more informed decisions about how to manage our own health. Body weight is a factor that appears to influence not only the risk of developing several types of cancer but also cancer survival.
To further understand how weight gain in midlife affects risk of postmenopausal breast cancer, researchers studied the effects of weight gain during two periods: 1) from age 20 to age 50 and 2) after age 50. The study consisted of approximately 72,000 women, age 55 to 74 at the beginning of the study. Results were presented for participants who had never used menopausal hormone therapy, as this group showed the strongest association between midlife weight gain and postmenopausal breast cancer risk.
Between age 20 and the start of the study, 57% of study participants had an increase in body mass index (BMI) of 5 kg/m2 or more. For a woman with a height of 5’4”, this equates to a weight gain of approximately 30 pounds.
- Regardless of weight at age 20, weight gain during midlife increased the risk of postmenopausal breast cancer. Women with a BMI increase of 5 kg/m2 between age 20 and study entry (at age 55-74) were almost twice as likely to develop postmenopausal breast cancer as women who maintained a stable BMI.
- Weight gain during either of the two age periods (20-50 and 50+) increased risk.
The researchers concluded that maintaining weight throughout adulthood may help women decrease their risk of postmenopausal breast cancer.
Reference: Sue LY, Genkinger JM, Schairer C, et al. Body mass index gain throughout adulthood may increase risk of postmenopausal breast cancer. Paper presented at: Annual Meeting of the American Association for Cancer Research; April 20, 2010; Washington, D.C. Abstract 4823.