Final Report Summary - CHILDGROWTH2CANCER (Childhood body size, growth and pubertal timing and the risk of cancer in adulthood) Cancer is a disease that usually takes a long time to develop. As childhood is a period of growth, it is possible that the roots of some adult cancers can be linked back to these ages. In our research, we looked at whether or not childhood body mass index (BMI) and height, both at single ages and as growth from 7 to 13 years of age, was associated with the risk of different forms of adult cancer. Additionally we looked at the effects of body size at birth and in adulthood as these are important time periods as well. To do this research, we used information on 372,636 Danish children who are part of the Copenhagen School Health Records Register.We found very different results depending on the cancer form we looked at. Higher BMI values increased the risks of bowel (colon), liver, pancreatic, throat (oesophagus) and thyroid cancer. For womb (endometrial) cancer and type 2 diabetes (a cancer risk factor) we found that only very high BMI values increased the risk. Interestingly, BMI did not increase the risk for all cancer forms that we studied. We did not find associations with brain (glioma), prostate or skin cancer. Children whose BMIs increased more than average from 7 to 13 years of age had increased risks of non-alcoholic fatty liver disease (a precursor to liver cancer) and womb (endometrial) cancer.We found that height is an indicator of risk for many forms of cancer. Taller children had increased risks of bowel (colon), brain (glioma), prostate, skin (melanoma), thyroid and womb (endometrial) cancer. We did not find associations between height and pancreatic or rectal cancer. Children who grew more than average in height from 7 to 13 years had increased risks of bowel (colon), prostate, skin (melanoma), and womb (endometrial) cancer. Although the main focus of our work was on child body size, we also examined birth weight and adult size in our project. Birth weight, even if it cannot be changed, is an indicator of risk for cancer. High birth weights increased the risk of brain (glioma) and prostate cancer. Low birth weights increased the risk of testicular cancer. For bowel (colon), liver and rectal cancer, the associations differed by low and high birth weight and between men and women. For prostate cancer, we found that taller boys at 13 years, no matter how tall they grew as adults, had increased risks of prostate cancer. Taken together, our project shows that child BMI, height and growth are linked to many forms of adult cancers. Our results suggest that all children should be helped to attain and maintain a healthy weight as to minimize the risk of adult cancer. Our results suggest that birth weight and height can be viewed as cancer risk factors. Although they cannot be changed, identifying these as potential risk factors can help individuals better understand their own personal risk, and thus change their behaviors to minimize the risk of developing cancer.
