A study found that overweight boys may be at greater risk of colon (bowel) cancer when they grow up but those who shed the pounds and achieve a healthy weight by young adulthood can skip the risk significantly.
Colon cancer is the 4th most common cancer in adults and several previous research findings have shown that overweight children are at higher risk of colon cancer as adults, but it is unclear whether changes in body mass index (BMI) between childhood and young adulthood alter this risk.
In this new study, Dr Britt Wang Jensen and Jennifer Baker from Bispebjerg and Frederiksberg Hospital, Copenhagen, Denmark have analysed the records of over 61,000 Danish school boys born between 1939 and 1959, to examine how changes in BMI in childhood and young adulthood are associated with colon cancer risk in adulthood.
Participants’ weight and height were measured at age 7 years and in young adulthood (age 17-26 years) and BMI was calculated. These young men were then linked with the Danish Cancer Register and followed from the age of 40 years to identify cases of colon cancer.
During an average (median) 25-year follow-up, more than 700 boys went on to develop colon cancer. Analyses showed that boys who were overweight (BMI greater than 17.88 kg/m2) at age 7 years but normal weight (BMI under 25.0 kg/m2) as young men had similar risk of adult colon cancer as those who maintained a stable, healthy weight throughout.
In contrast, overweight boys who remained overweight as young men had twice the colon cancer risk, said the study.
“Overweight boys that lose weight and achieve a normal-weight status by young adulthood do not carry an increased risk of adult colon cancer compared with boys who remain normal-weight as young men. However, overweight boys who remain overweight as young men have an increased risk of adult colon cancer. These results highlight the importance of weight management in childhood,” said the study.