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A recent study has found evidence that adolescents who are overweight or have obesity may be at a 407% increased risk of getting pancreatic cancer, the 6th most deadly form of cancer in the world. To determine this relationship, Levi et al. conducted a study of 1,087,358 Israeli Jewish men and 707,212 Jewish women who received a mandatory physical examination as an adolescent between the years 1967 through 2002. The authors then combined the adolescent physical exam data with information from the Israeli national cancer registry to see if there was a link between being overweight and getting cancer later in life.
In the United States, 39.6% of adults and 18.5% of children and adolescents have obesity. Obesity is a strong contributing risk factor to a wide range of other diseases, including coronary heart disease, stroke, and diabetes. Additionally, obesity is estimated to cause approximately 6% of all cases of cancer. The research from this recent study adds support for the relationship between excess weight and the risk of cancer later in life.
The authors divided the 1.8 million Israeli participants into groups based upon their body weight percentiles when they were initially examined (between age 16-19). The heaviest 5% of patients were referred to as being in the “95th Body Mass Index (BMI) percentile”. Compared to patients in the 5-85th weight percentiles, those who had obesity as adolescents (95th percentile) were 367% more likely to have pancreatic cancer (if men), or 407% more likely to have pancreatic cancer (if women), at some point in their life. This effect was strongest when comparing patients with obesity to patients who were of lower BMI, but the study also showed that this effect occurs along a gradient.
The authors found that participants who were overweight (but did not have obesity) as adolescents had a 97% higher risk of pancreatic cancer compared with people who were of normal weight as adolescents. Further, when the authors compared those who were on the “high” end of the normal BMI range as adolescents (aka those in the 75th-85th percentile) to those on the “low” end of the normal BMI range (aka those in the 55th-25th percentile), there was a 49% increase in risk of pancreatic cancer. Importantly, this study does not provide evidence of a direct link between weight status and pancreatic cancer. It is possible that patients’ weight as an adolescent is correlated with another behavior that more directly contributes to pancreatic cancer. Regardless, the strength of association observed warrants strong consideration.
What does this study add to our understanding of pancreatic cancer? Most evidently, it establishes the importance of making it easier for adolescents to maintain a healthy weight. This can be difficult because a shifting social landscape has turned food choices that were once an “occasional” option into everyday selections. Strikingly, nearly half of the food energy intake of Australian teenagers comes from “discretionary” foods with low nutritional value. Consumer preferences are changing in ways such that the norm is trending toward obesity, with increasing numbers of calories consumed per day and sustained low levels of physical activity.
Children who are overweight at age 4 have 7-fold greater odds of being overweight or obese by age 7-8, relative to four-year-olds of healthy weight. Even more extreme, children who have obesity at age 4 have 27-fold greater odds of being overweight or obese by age 7-8. The same study found that parental BMI is associated with children’s weight outcomes; if children at age 6 have mothers who are overweight or obese, they are significantly more likely to have obesity by age 7-8.
Obesity has increased significantly across the globe in recent years. Increasing numbers of children and adolescents are overweight or obese, and there is evidence to suggest that obesity at a young age is a strong predictor of obesity later in life. Given Levi et al’s recent study showing a connection between adolescent weight status and pancreatic cancer, there is now even stronger evidence to suggest a need for comprehensive reform aimed at making it easier for individuals to make healthy decisions.
Levi, Z., Rottenberg, Y., Twig, G., Katz, L., Leiba, A., Derazne, E., . . . Kark, J. D. (2018). Adolescent overweight and obesity and the risk for pancreatic cancer among men and women: a nationwide study of 1.79 million Israeli adolescents. Cancer. doi: 10.1002/cncr.31764
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