It is widely recognized that excess weight or obesity heightens the risk of cancer, but new research offers important nuances to this connection.
The timing of weight gain is significant and varies between men and women.
Researchers from several Swedish institutions examined health data previously collected from over 630,000 people. These individuals had their weight recorded periodically between the ages of 17 and 60.
The weight data was then compared with cancer incidence in the study group to identify patterns, revealing notable associations.
“Most studies on body weight and cancer have focused on weight at a single point in time – typically in mid-to-late adulthood – or on weight changes between two points,” note the researchers in a preprint, which has not yet been peer-reviewed.
“Associations between life-course weight trajectories based on multiple weight assessments and the risk of developing cancer remain less explored.
“Since the timing and extent of weight changes vary across individuals, it may however be important to consider weight changes continuously rather than at one or two time points.”
Rapid weight gain at any life stage was linked to a higher risk of several cancers: primarily liver cancer and esophageal adenocarcinoma for men, endometrial cancer for women, and renal cell carcinoma and pituitary tumors in both genders.
frameborder=”0″ allow=”accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share” referrerpolicy=”strict-origin-when-cross-origin” allowfullscreen>In men, weight gain before age 45 was more strongly associated with cancer, particularly esophageal and liver cancer.
Chronic inflammation, insulin resistance, and gastroesophageal reflux disease (GERD) may be contributing factors here.
For women, gaining weight after age 30 appeared more hazardous, possibly due to hormonal changes during middle age, according to the researchers.
For some cancers, such as pancreatic cancer, the risk was most closely associated with a person’s weight at age 17, rather than subsequent changes.
The data also indicated that an earlier onset of obesity generally correlates with a higher cancer risk.
Overall, this presents a complex picture where gender, age of weight gain, rate of weight increase, and cancer type are all significant factors.
“By distinguishing between initial adult body weight and subsequent weight change, and allowing weight dynamics to vary across age intervals, our analyses provide a more nuanced understanding of how adiposity over the life course relates to cancer risk,” explain the researchers.
This research offers a more detailed understanding of the relationship between weight gain and cancer than previously available. However, as observational data, it does not establish causation, and the data lacked some specific details.
Important factors such as participants’ diet and exercise habits were not adjusted for, which might have influenced some of the observed patterns.
These findings also relate to an earlier study by some of the same researchers, which demonstrated that the timing of weight gain affects mortality risk as well as cancer risk.
For improving treatment and public health, the issue is not solely about lowering obesity rates to reduce cancer risk; it’s more intricate than that.
The researchers advocate for cancer prevention strategies that consider an individual’s sex and age.
Related: Scientists Identify The Most Dangerous Time in Life to Gain Weight
“Both early adult body weight and weight gain across adulthood were associated with the risk of most established and some potentially obesity-related cancers, with heterogeneity by cancer site, sex, and timing of weight gain,” state the researchers.
“In the context of the rising prevalence of obesity and cancer in Western countries and globally, the findings highlight the importance of a life-course perspective on weight management for cancer prevention.”
The research was presented at the European Congress on Obesity, and the preprint is available on medRxiv. It has not yet undergone peer review.
