Real‐World Weight Loss Is Associated With a Reduction in Cancer Risk

OBJECTIVE: Obesity is a major risk factor for multiple cancers, yet the impact of nonsurgical weight loss on cancer risk remains uncertain. Our objective was to evaluate whether real-world nonsurgical weight loss is associated with a reduced risk of developing cancer. METHODS: We conducted a retrospective observational study of 143,630 adults (BMI ≥ 30) from an integrated US health system's electronic health records (2000-2022). Cases with incident cancer were compared to matched controls. Using generalized linear models with a logit link, we assessed whether BMI change over 3-, 5-, and 10-year intervals is associated with the risk of diagnosis for obesity-related and other cancers. RESULTS: Among 143,630 patients, 7703 cases and 135,927 controls were identified. Each 1% BMI reduction was linked to lower obesity-related cancer risk at 3 years (OR, 0.990; 95% CI, 0.984-0.996; p < 0.001), 5 years (OR, 0.989; 95% CI, 0.984-0.995; p < 0.001), and 10 years (OR, 0.992; 95% CI, 0.984-1.000; p = 0.057). Similar associations were observed for other cancer types across all intervals (OR < 1; p < 0.001). CONCLUSIONS: Real-world weight loss was associated with a decreased risk of obesity-related and other cancers.