In postmenopausal women the risk of breast cancer increased due to excess fat deposits in the body with normal BMI. This was reported by specialists from the American Association of Cancer Research. The results of the observations were published today on the official website of the organization.
The body fat level is usually measured using the body mass index (BMI), which shows the relationship between weight and height. BMI indicators would be convenient for estimating the amount of fatty deposits in the body, but this method of analysis does not allow you to extract from the total mass the proportion of muscles and bones. Because of this, scientists were unable to determine how excess fat deposits affect the health of people whose BMI is within normal limits.
Therefore, in the new study, specialists used dual-energy X-ray absorptiometry (DRA), a technology that can specifically measure the fat content, adjusted for muscle and bone. The main material was taken from one of the past observational studies, in which women participated in postmenopause at the age of 50-79 years. The participants had normal BMI (from 18.5 to 25) and had no previous oncological diseases. During 16 years of observation, 182 patients (of 3460 participants) developed invasive breast cancer, 146 of them had an estrogen-positive reaction. An analysis of the relationship between weight and incidence showed that, with normal BMI, excess fat deposits double the risk of developing breast cancer. In addition, every fifth extra kilogram of fat increases this risk by 35%.
Scientists also noted that women with a high proportion of fat in the body have a low-activity lifestyle, and therefore daily moderate exercise may be necessary even for those who are not obese. According to experts, the results are extremely unexpected, as many doctors and patients in the modern world measure the risk of developing various diseases based on BMI, which, as this work showed, can not give reliable results.