Early CRC more likely in obese young adults

Obesity during early adulthood seems to significantly aggravate the risk of early-onset colorectal cancer (CRC), reports a recent study.

The study included 747 CRC patients and 621 matched controls. Only those younger than 55 years of age were eligible for inclusion. Self-reported height and weight at ages 20 and 30 years, and at approximately 10 years before CRC diagnosis, were collected and used for body mass index (BMI) calculation.

Multiple logistic regression analysis showed that obesity was a strong and significant risk factor for CRC, regardless of when BMI was measured. For instance, BMI ≥30 kg/m² at 20 years of age more than doubled the likelihood of CRC (adjusted odds ratio [OR], 2.56, 95 percent confidence interval [CI], 1.20–5.44). At this age, every 5-kg/m² increase in BMI increased CRC odds by over 40 percent (OR, 1.44, 95 percent CI, 1.18–1.75).

Similarly, obesity at 30 years of age increased CRC likelihood by more than two times (adjusted OR, 2.06, 95 percent CI, 1.25–3.40), with each 5-kg/m² increase in BMI correlating with more than 30-percent rise in CRC odds (adjusted OR, 1.36, 95 percent CI, 1.15–1.61).

Even when measured 10 years before diagnosis, obesity continued to be a strong risk factor for CRC, increasing the likelihood of diagnosis by almost twice (adjusted OR, 1.88, 95 percent CI, 1.30–2.73). Each 5-kg/m² increment in BMI increased the odds of CRC by 36 percent (adjusted OR, 1.36, 95 percent CI, 1.18–1.58).

The present study “strongly supports suggestions that recent increases in prevalence of obesity in younger generations may be an important factor in the increases in incidence of early-onset CRC in many countries,” the researchers said.

“Our results suggest that measures to prevent or curb the obesity epidemic in younger generations are likely to be as crucial for preventing CRC as they are for preventing other common diseases,” they added.