Cancer
A prospective analysis on adult weight change and risk of colorectal cancer incidence and mortality in the NIH-AARP Diet and Health Study Wen-Yi Huang* Wen-Yi Huang Kathryn Hughes Barry Steven C. Moore Semi Zouiouich Rashmi Sinha Erikka Loftfield Sonja I. Berndt
Obesity has been rapidly increasing worldwide. Although obesity is a risk factor for colorectal cancer (CRC), the influence of weight change over adult lifetime on risk of CRC incidence and mortality is unclear.
With >20 years of follow-up, we prospectively evaluated the risk of CRC incidence (n=9,255) and mortality (n=2,934) in relation to adult weight change among men and women (n=292,238) in the NIH-AARP cohort. Participants reported their weight and height at age 18, age 50, and enrollment (aged 50-71), and their maximal adult weight. Hazard ratios (HRs) and 95% confidence intervals (CI) were computed using multivariable-adjusted Cox proportional hazard models.
Compared with individuals whose BMI never exceeded 25 kg/m2 over their lifetime, those who first exceeded a BMI of 25 kg/m2 at either age 18, age 50, or enrollment all had a 20% higher risk of CRC (HR=1.2, all P-values <0.05). Participants who had a lifetime maximal BMI between >25 to 30 kg/m2 had a 10% increased risk (95% CI:1.1-1.2) and those with a maximal BMI exceeding 30 kg/m2 had a 30% increased risk (95% CI:1.2-1.4). Moreover, compared with stable weight from age 18 to 50 years, weight gain of >4, >2-4, and >1-2 kg per 5 years was associated with a 30% (95% CI:1.2-1.4), 20% (95% CI:1.1-1.3), and 10% (95%CI:1.0-1.2) increased risk of CRC incidence, respectively. We observed similar risk patterns for CRC mortality. For example, weight gain of >4, >2-4, and >1-2 kg per 5 years from age 18 to 50 years, compared with stable weight, was associated with a 70% (95% CI:1.5-1.9), 30% (95% CI:1.2-1.5), and 20% (95%CI:1.0-1.3) increased risk of CRC mortality, respectively.
In conclusion, our study demonstrates that exceeding a normal weight at any age and weight gain from early to middle adulthood are associated with an increased risk of both CRC incidence and mortality. These findings highlight the importance of maintaining healthy weight throughout the adulthood.