Young adults dealing with obesity face a higher risk of developing cancer before midlife compared to peers maintaining a moderate weight, Healthline reported on October 26 based on a study published in the Annals of Internal Medicine.
That study tracked 6,313,338 adults between the ages of 20 and 39 who had no history of cancer. Researchers utilized data from the Korean National Health Insurance Service database and followed participants for an average of 11 years, adjusting for factors such as age, sex, smoking status, alcohol consumption, physical activity, income, residential area, and metabolic comorbidities like hypertension and diabetes.
Cancer Risk Rises Progressively With Weight Gain
Over the course of the 11-year follow-up period, researchers recorded 151,893 cases of cancer among the cohort. The incidence rate climbed steadily across weight categories, starting at 1.84% for normal-weight individuals. That figure rose to 2.24% for participants with class I obesity and reached 2.62% for those with class II obesity.
Ketan Thanki, a board-certified colorectal surgeon with the MemorialCare Todd Cancer Institute at Long Beach Medical Center in Long Beach, California, who was not involved in the study, told Healthline that obesity itself causes states that promote cancer formation. Males showed a higher relative association between obesity and cancer, while females demonstrated a higher absolute risk. The researchers also noted that absolute risk was higher among adults ages 30 to 39.
Abdominal Obesity Threatens Moderate Weight Individuals
The study also linked abdominal obesity, measured by waist circumference, to elevated cancer risk even among individuals categorized at a moderate weight. Participants with waist circumferences exceeding specific thresholds faced heightened risks similar to those classified as overweight.
The study utilized thresholds from the Korean Society for the Study of Obesity, setting cutoffs at over 90 centimeters (35.4 inches) for males and over 85 centimeters (33.46 inches) for females. By contrast, guidelines from the National Heart, Lung, and Blood Institute (NHLBI) place waist circumference measurements that can increase health risks at 101.6 centimeters (40 inches) for males and 88.9 centimeters (35 inches) for females. Previous research indicates a potential 11% increased risk of cancer for people exceeding the thresholds, even if they were physically active.
Researchers observe no obesity link to early breast cancer
While smoking habits further compounded cancer risk in the cohort, researchers observed no association between obesity and breast cancer diagnosed before the age of 50. Diet, exercise, and medications offer viable paths to mitigate these outcomes.
“Diet, exercise, and now medications can all be used very effectively to reduce one’s weight and, hopefully as a result, cancer risk,” Thanki told Healthline. He added that because of differences between South Korean populations and those in countries such as the United States, further study is required to determine how this translates, though he expects the underlying trend to apply across cultures.
Frequently Asked Questions About Early-Onset Obesity and Cancer Risk
How was waist circumference measured in the study?
Researchers used thresholds set by the Korean Society for the Study of Obesity, establishing cutoffs of over 90 cm for males and over 85 cm for females.
What database provided the research data?
The study drew from the Korean National Health Insurance Service database, analyzing records for over 6.3 million adults.
Were smoking habits factored into the cancer rates?
Yes, researchers adjusted for smoking status and found that individuals who currently smoke or previously smoked faced a higher risk of developing cancer than those who never smoked.
Did the study find a link to all cancer types equally?
The strongest associations appeared in specific cancers, and researchers observed no association between obesity and breast cancer diagnosed before the age of 50.
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