Men who had a high body mass index (BMI) as children are at an elevated risk of obesity-related cancer later in life, even if their weight was normal in young adulthood, according to a new study from researchers at the University of Gothenburg, Sweden. Célind et al published their findings in the journal Cancer Communications.
Obesity-related cancers include a significant group of tumor diseases, many of which are on the rise in industrialized countries. They include cancer of the mouth, liver, gallbladder, pancreas, colon, thyroid, skin (malignant melanoma), and blood. The association between high BMI in adulthood and an increased risk of obesity-related cancer was already known, but the risk associated with high BMI during childhood and puberty has not been detailed before.
The new results are based on the BMI Epidemiology Study Gothenburg, a population-based cohort including BMI during development and diagnostic data from high-quality Swedish registers on 36,565 men born from 1945 to 1961.
Remaining Cancer Risk
The scientists analyzed BMI of individuals at the age of 8 years and again at age 20 and followed their cancer diagnoses from age 20 through approximately 40 years thereafter. This long follow-up period was crucial to the study since most cases of obesity-related cancer occur in upper middle age.
The study showed that the group of boys who were overweight at age 8 had an increased risk of obesity-related cancer in adulthood. This applied particularly to those who were still overweight at age 20. However, an increased risk also remained when BMI had become normal by age 20.
“Alarmingly, a near 40% excess relative risk remained even for the group of boys who were overweight at age 8 but had a normal weight at age 20, compared to the group with normal weight at both ages,” said Jimmy Célind, MD, a researcher at Sahlgrenska Academy's Institute of Medicine at the University. He is also a pediatrician at the Queen Silvia Children's Hospital and the study’s first author.
Overweight in childhood followed by normal weight in young adulthood thus resulted in a persistently increased risk of adult obesity-related cancer, which this study is the first to show.— Jimmy Célind, MD
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More Early Measures
The authors behind the study emphasized that the results are not applicable to individual risk. “The increased risk for the individual over a life course is minor. However, in a population like the Swedish, where one in five children are overweight, these findings point toward significant negative impact on future populational health.”
Dr. Célind commented: “The results show that preventive measures against obesity-related cancer should start early in childhood. If decision-makers responsible for public health at the country or even global level are serious about every child's right to a healthy start in life, they need to step up the actions taken in early years.”
Disclosure: For full disclosures of the study authors, visit onlinelibrary.wiley.com.
