(Reuters Health) – Elderly women with weight loss may have a lower risk of developing invasive breast cancer than those who hold or hold weight, says a major US study.
Although obesity has long been associated with increased risk for breast cancer, previous research has provided a mere picture of potential slimming that helps reduce the risk. According to this study, researchers estimated weight and height to lower BMI to over 61,000 women twice, every three years.
Then, researchers followed women for an average of 11.4 years. During this time 3,016 women developed invasive breast cancer.
Compared to women with stable weight during the first three years of study, women who lost at least 5 percent of body weight during the first three years were 12 percent more likely to develop breast cancer over the next decade or so.
"Our results are consistent with the fact that a woman may fall into cancer risk even if they are overweight or obese after losing weight, because almost no one in the current cohort study has lost enough weight to achieve normal weight," said lead researcher Rowan Chlebowski Hope National of National Medical Center in Duarte, California.
"It should be an encouraging result for women, because many people can achieve a modest continuous weight loss while weight loss that is enough to return to non-obese or overweight is quite difficult," Chlebowski said in an e-mail.
All women in the study had had menopause when menstruation stopped and estrogen production weakened. After menopause, women's main estrogen is fatty tissue; Overweight or obese may increase the risk of cancer because estrogen can help the tumors grow.
"Women who are overweight or obese are likely to have increased the risk of postmenopausal breast cancer due to increased hormone levels in fat cells," said Tri. Daniel Schauer, Cincinnati College of Medicine, who was not involved in the study.
"These hormones, especially estrogen, can contribute to the development of postmenopausal breast cancer," Schauer told Reuters Health via e-mail. "Loss of weight reduces the amount of circulating hormones."
Of the approximately 41,000 women in the study who had a steady weight in the first three years, participants had an average weight of 26.7 patients who were overweight.
12,000 women who gained weight during the study also started with an average BMI of 26.7.
Women who have lost weight began to get heavier.
Approximately 3 300 women who lost weight unintentionally started at BMI 27.9 and half of them lost more than 17 pounds. Women who lost weight intentionally started on average at 29.9 BMI, only 30 of the BMIs are considered to be obese and half of them lost more than 20 pounds.
The weight gain of at least 5% was not associated with increased risk for breast cancer, researchers reported in the Cancer Journal. But this weight gain was associated with a 54 percent greater risk of developing "triple negative" breast cancer, aggressive and difficult to treat cancer type.
The study was not a controlled experiment designed to demonstrate whether a change in weight over time or immediately affect women's risk of developing or dying breast cancer.
Researchers only measured the weight of the woman twice, at the beginning of the study and three years later, and the changes that weighted women after it had been announced were not in medical examinations.
For most people, weight gains over time, said Dr Graham Colditz from the University of Washington Medical School in St. Louis, who was not involved in the study.
"So the first realistic goals are to end the job, which is health benefits, even if you are overweight," Colditz said in an e-mail.
"After this, sensible and slow weight loss is a good goal," Colditz added. "The five and ten pounds are a great start, which is easier to maintain over time."
SOURCE: bit.ly/2AreUsz Cancer, online October 8, 2018.