It is well known that having excess body weight is a risk factor for a number of conditions at including least nine different types of cancer.
Overweight and obesity can lead to greater insulin resistance, chronic in ammation, DNA damage and changes in hormone metabolism. What is less known in this area is what particular aspects of overweight and obesity might contribute most to this risk.
Researchers investigated this, focusing on two aspects of overweight and obesity – how many years a person has been obese and the degree of overweight or obesity. The study involved more than 70,000 American women and followed them over a 12 year period. The primary interest was the association between body fatness and cancer. About two-thirds of the women in the study had been overweight or obese at some point during their lives and were compared to women who had never been overweight or obese.
Results showed that the duration of overweight or obesity was an important risk factor for cancer. For every decade that weight was carried the risk of cancer increased by 7%. Risk increased further when the degree of overweight and obesity was taken into account.
This study suggests, that in addition to the level of overweight or obesity, the duration of carrying extra weight also increases risk of cancer. This supports the importance of being consistent with exercise across your life course and maintaining a healthy weight.
Reference: Arnold, M et al. Duration of adulthood overweight, obesity, and cancer risk in the Women’s Health Initiative: a longitudinal study from the United States. PLoS Medicine Epub online August 16, 2016. doi: 10.1371/journal.pmed.1002081.