Elderly women who lose weight may have a lower risk of developing breast cancer than those who maintain or gain weight, according to a large US study.
While obesity has long been associated with an increased risk of breast cancer, previous research offers a mixed picture of weight loss opportunities to help reduce this risk. For the current study, researchers evaluated weight and height to calculate the body mass index (BMI) for more than 61,000 women twice, three years.
Subsequently, the researchers followed women for an average of 11.4 years. During this time, 3,061 women developed invasive breast cancer.
Compared to women who had a fixed weight during the initial three years of the study, women who lost at least 5% of their body weight in the first three years were 12% less likely to develop breast cancer over the next decade about.
"Our results are consistent with a woman who can reduce the risk of cancer even if she remains overweight or obese after losing weight, since almost none of the women in our team's current analysis has lost weight enough to succeed normal weight ", the author of the study, Dr. Rowan Chlebowski from the City of Hope National Medical Center in Duarte, California.
"This should be an encouraging result for women, as moderate weight loss can be achieved by many, while weight loss sufficient to return to a class that is not suffering from obese or overweight is quite difficult," said Chlebowski via email.
All women in the study had gone through menopause when menstruation and hormone production stopped drops of estrogen. After menopause, the main source of estrogen in women is fatty tissue. being overweight or obese can increase the risk of cancer because estrogen can help in the development of tumors.
"Women who are overweight or obese probably have an increased risk of postmenopausal breast cancer because of the increased hormone levels associated with adipocytes," Dr. Daniel Schauer of the University of Cincinnati College of Medicine, who did not participate in the study.
"These hormones, especially estrogens, can promote the development of postmenopausal breast cancer," Schauer told Reuters Health by email. "Weight loss reduces levels of circulating hormones."
Among the approximately 41,000 women in the study who had a fixed weight during the initial three years, the participants had an average BMI of 26.7, which is considered excessive.
The 12,000 women who gained weight during the study also started with an average BMI of 26.7.
Women who lost weight started heavier.
The approximately 3,300 women who lost weight unexpectedly started with a BMI of 27.9 and half of them lost more than 17 pounds. Women who lost weight deliberately started with an average BMI of 29.9, just shy of the BMI cut of 30 to be considered obese, and half of them lost more than 20 pounds.
Weight gain of 5% or more was not associated with an increased risk of breast cancer as a whole, researchers reported in the Cancer journal. But this weight gain was associated with a 54% higher risk of developing a "triple negative" breast cancer, an aggressive and difficult to treat cancer.
The study was not a controlled experiment aimed at demonstrating whether and how changes in body weight over time could directly affect the risk of developing or death from breast cancer.
Researchers only measured the weight of women twice at the beginning of the study and again three years later, and any changes in women reported after that were not verified by medical examinations.
For most people, weight moves over time, said Dr. Graham Colditz of the University of Washington Medical School in St. Petersburg. Louis, who did not participate in the study.
"So the first realistic goals are to work to stop winning. There are health benefits to that, even if you're overweight," Colditz said by email.
"After that, proper and slow weight loss is a good goal," Colditz added. "Five to ten pounds is a great beginning that is easier to maintain over time."
SOURCE: bit.ly/2AreUsz Cancer, online October 8, 2018.