Weight gain spread over several years in adulthood would increase the risk of cancers associated with obesity, by nearly 50% in men and 20% in women. These American data show how important it is to also take an interest in progressive weight gain over the course of life.
300,000 people followed
The data in this study is based on monitoring the BMI (body mass index) at five different periods in the lives of nearly 300,000 Americans (177,500 men and 111,500 women), between 18 and 65 years old. On average, each individual was followed personally for 15 years in order to assess the development of forms of cancer associated with obesity (cancer of the breast, colon, uterus, pancreas, etc.). The interest of this study is to propose for the first time an investigation at several stages of life and no longer on an ad hoc basis. In this sample, 9,400 women and 5,500 men contracted cancer linked to their obesity beyond the age of 65.
Being overweight doubles the risk of cancer
The results are of particular concern for humans. Indeed, a man who evolves from a BMI of 22 to 27 records a 50% increase in the risk of developing cancer related to his obesity, compared to a man who maintains a healthy BMI. And for higher BMI levels, the risk climbs even further to 53%. In women, the risk is lower, but not non-existent: for a change in BMI from 23 to 32, it increases by 17% compared to a stable and healthy BMI. For the authors, this study is particularly interesting because it depicts the unfavorable evolution of the risk of cancer during life with a progressive increase in weight. It therefore provides additional arguments for maintaining a healthy and/or stable weight throughout adult life.
Hannah Lennon1,Matthew Sperrin:Lifetime BMI trajectory classes and obesity-related cancer risk in a US retrospective cohort study Abstracts from the NCRI Cancer Conferences