Weight loss linked with heightened cancer risk
Individuals who lost more than 10% of their body weight within the past two years were more likely to be diagnosed with cancer in the 12 months after weight loss than those who didn't lose weight.
Recent weight loss is associated with a significant risk of cancer, new results of a prospective cohort analysis show.
Researchers assessed cancer risk among female participants of the Nurses' Health Study who were followed from June 1978 to June 2016 and male participants of the Health Professionals Follow-Up Study who were followed from January 1988 to January 2016. All participants were at least 40 years old at baseline and had no history of cancer. Investigators calculated weight changes based on participant weights reported biennially and categorized the intentionality of weight loss based on reported increases of physical activity and/or diet quality. They then compared rates of cancer diagnoses in the 12 months after weight loss with rates in those who did not lose any weight. Findings were published Jan. 23 by JAMA.
Of the 157,474 participants, 71.1% were female, median age was 62 years, and 95.2% were White. Participants were followed for an average of 28 years. Among those who reported a weight loss of more than 10% body weight, there were 1,362 cancer cases per 100,000 person-years in the year after weight loss. In comparison, there were 869 cancer cases per 100,000 person-years in those who didn't lose weight (between-group difference, 493 cases per 100,000 person-years [95% CI, 391 to 594 cases per 100,000 person-years]; P<0.001). Cancer diagnoses were more common in participants with low weight loss intentionality, or those with no increase in physical activity or diet quality, with 2,687 cancer cases per 100,000 person-years recorded compared with 1,220 cancer cases per 100,000 person-years in those who did not lose weight (between-group difference, 1,467 cases per 100,000 person-years [95% CI, 799 to 2,135 cases per 100,000 person-years]; P<0.001). In patients with recent weight loss, cancer of the upper gastrointestinal tract, including the esophagus, stomach, liver, biliary tract, or pancreas, was common. Data showed 173 upper gastrointestinal tract cancer cases per 100,000 person-years in those with weight loss versus 36 cases per 100,000 person-years in those who didn't lose weight (between-group difference, 137 cases per 100,000 person-years [95% CI, 101 to 172 cases per 100,000 person-years]; P<0.001).
“The amount of weight loss was similar among people with early-stage cancer compared with those with later stage cancer, suggesting that weight loss is identified during both early and advanced cancer stages,” the researchers noted. Many different conditions besides cancer can also cause weight loss, they added.
A limitation to the study is that body weights were self-reported and not verified by objective measurements. Researchers also did not have access to data on cancer-related symptoms and laboratory abnormalities that might occur at the same time as weight loss.