Early-onset colorectal cancer burden attributable to early-life obesity from 2000 to 2020 with projections to 2040
Menée à partir de données australiennes 1990-2022, cette étude estime la part des cancers colorectaux de survenue précoce attribuable à l'obésité pendant l'adolescence puis réalise une projection jusqu'en 2040
Purpose: Early-onset colorectal cancer (age <50 years) incidence has increased globally since the 1990s for unknown reasons. Early-life exposure to established risk factors like adiposity is suspected to play a role, but the contribution to the rising disease burden remains unknown. This study quantified the potential impact of rising early-life obesity on early-onset colorectal cancer in Australia.
Methods: Population attributable fractions for early-onset colorectal cancer were derived from meta-analytic relative risks and obesity prevalence estimates in adolescents (10–19-year-olds), using body mass index data for 1990–2022 from the Noncommunicable Diseases Risk Factor Collaboration. Under age-specific carcinogenesis latency assumptions, we linked adolescent obesity prevalence estimates to colorectal cancer incidence across age groups (20–29, 30–39, and 40–49 years) using observed cancer incidence data from Australian cancer registries covering 2000–2019 and age-period-cohort modelling to generate scenario-based estimates of incidence and obesity-attributable cases through 2040. Trends in obesity-attributable colorectal cancer incidence were quantified using joinpoint regression.
Results: The proportion of early-onset colorectal cancers attributable to adolescent obesity across 1990–2022 rose from 2% to 6% in men and 1–3% in women (average annual change: 3–4%). Although absolute attributable incidence rates were low, they increased 2–20% per year, varying by period, age-dependent lag, and sex. Under the projection assumptions applied, scenario estimates suggest that adolescent obesity could account for an estimated 1465 early-onset cases by 2040.
Conclusion: Early-life obesity is estimated to account for a growing yet minor fraction of early-onset colorectal cancers in Australia and is therefore unlikely to be a major driver of the rising disease incidence. These findings suggest that childhood obesity prevention programs may have only a small public health impact on early-onset colorectal cancer prevention. Therefore, it is imperative that other causal risk factors – especially early-life exposures – are identified to inform prevention strategies that stem the rising disease burden.
Cancer Epidemiology , article en libre accès, 2026