AICR
Key Takeaways
- A higher birthweight and increased body size as a child, teen or young adult may raise the risk of getting colorectal cancer later in life.
- A review of 37 studies as part of the Global Cancer Update Program (CUP Global) confirms that early life body mass index (BMI) and body size are causally linked with colorectal cancer risk.
- This study fills an important gap in current knowledge. Learning how weight in early life affects cancer risk can help support more effective prevention strategies.
Having a greater birthweight or higher body size during childhood, adolescence or young adulthood is associated with an increased risk of colorectal cancer in later life. This is the conclusion of a major systematic review and meta-analysis of 37 published studies, which is part of World Cancer Research Fund International’s Global Cancer Update Program (CUP Global). AICR is a partner in CUP Global.
Published in the International Journal of Cancer, the study was undertaken by researchers at Wageningen University & Research in Wageningen, Netherlands. It is one of the first reviews with the specific aim of exploring all of the research examining how factors such as weight, height and body size in specific early life stages may relate to our risk of colorectal cancer as we age.
What Did the Research Show?
The review found that most studies used a measure of BMI to evaluate the links between body size and colorectal cancer. The detailed results demonstrating that increased birthweight and body size in childhood, adolescence, and young adulthood are linked with future colorectal cancer risk include:
- For young adults (18–25 years): each 5kg/m2 increase in BMI was associated with a 12 percent increased colorectal cancer risk.
- For adolescents (10–19 years): each 1 standard deviation increase or each 5kg/m2 increase in BMI was associated with a 5–18 percent increased colorectal cancer risk.
- Each 1 kg (2.2 lb) increase in birthweight was associated with a 9 percent increased colorectal cancer risk.
- For children (2–9 years): each 1 standard deviation increase in BMI was associated with an increased risk of developing colon cancer.
The results of the review were published as part of World Cancer Research Fund International’s Global Cancer Update Programme – the world’s largest and most authoritative source of scientific research on cancer prevention and living with and beyond cancer.
What Do These Results Mean?
The strength and novelty of the study is that the results were assessed by the CUP Global panel of experts, who concluded that there was strong evidence that higher birthweight, as well as higher BMI in early life, were causally associated with an increased risk of colorectal cancer in adulthood.
“Although the relationship between adult body size and colorectal cancer risk is well-documented, the potential influence of measures of body size during early life is less understood,” says Dr. Dieuwertje Kok, an associate professor of nutrition and cancer at Wageningen University & Research and one of the study researchers. “This study bridges the existing knowledge gap and enhances our understanding of how early life factors may affect colorectal cancer risk in adults.”
Dr. Helen Croker, the assistant director of research and policy at World Cancer Research Fund International, says: “Cancer is a complex disease that develops over several decades, so better understanding of its early origins is critical for more effective prevention efforts and understanding the research gaps. The results of this study show that raised body mass index across childhood through young adulthood is an important risk factor for colorectal cancer.”
Take Action: Healthy Lifestyle Habits
If you are raising children, instill healthy lifestyle choices early on, since it may help prevent cancer later. Here are some steps you can take:
- Focus on healthy habits. Encourage regular meals and snacks that include vegetables, fruits, whole grains and protein. Build meals using the New American Plate model. Soda, sweets and salty snacks should be occasional treats, not everyday staples.
- Be a role model. Children learn by example. Let them see you enjoying balanced meals, being active and speaking positively about your own body.
- Keep mealtimes relaxed and pleasant. Share conversation about your day. Do not use food as rewards or restrict food as punishment.
- Respect appetites. Let children tune in to their own hunger and fullness cues so they learn to build a healthy relationship with food. Avoid pressuring kids to “clean their plate.” They should listen to their appetite and stop eating when they feel full.
- Support active play every day. Physical activity should be fun and age-appropriate, like playing outside, biking or dancing. It’s more about movement and joy than exercise for weight control.
- Do food activities together. Grocery shop, choose recipes and cook with children to teach them these essential life skills.
“Understanding the impact of early life body weight on cancer risk later in life can be empowering,” says Dr. Nigel Brockton, PhD, VP of research at AICR. “Lifestyle has a huge impact on our cancer risk, and a better understanding our personal risks can help inform and motivate our adoption of healthy lifestyle habits.”
