Comparing waist circumference with body mass index on obesity-related cancer risk: a pooled Swedish study
Ming Sun, Christel Häggström, Marisa da Silva, Innocent B. Mboya, Ylva Trolle Lagerros, Karl Michaëlsson, Sven Sandin, Jerzy Leppert, Sara Hägg, Sölve Elmståhl, Patrik K. E. Magnusson, Stefan Söderberg, Weiyao Yin, Abbas Chabok, Angela Wood, Tanja Stocks, Josef Fritz
Abstract
BACKGROUND: General adiposity, assessed by body mass index (BMI), is a well-established cancer risk factor. This study compared waist circumference (WC), a measure of abdominal adiposity, with BMI as a risk factor for obesity-related cancers, and assessed whether WC provides additional information beyond BMI. METHODS: We analyzed data from 339 190 individuals in a pooled Swedish cohort with baseline BMI and WC assessments from 1981 to 2019 (61% objectively measured, mean age 51.4 years). Cancer diagnoses were obtained from the Swedish Cancer Register. Hazard ratios (HRs) for WC and BMI were calculated using multivariable-adjusted Cox regression. To account for WC's greater variability, we corrected HRs using regression dilution ratios. To assess WC's additional contribution beyond BMI, we analyzed WC residuals in multivariable, BMI-adjusted models. RESULTS: During a median follow-up of 13.9 years (interquartile range: 8.0-22.5), 18 185 IARC-established obesity-related cancers were recorded. In men, a 1-standard deviation (SD) increase in WC was associated with a 25% higher risk of obesity-related cancers (HR1-SD = 1.25, 95% CI = 1.21 to 1.30), compared to a 19% increase for BMI (HR1-SD = 1.19, 95% CI = 1.15 to 1.23, P = 0.014 for heterogeneity). Among women, associations were weaker and similar for both WC (HR1-SD = 1.13, 95% CI = 1.11 to 1.16) and BMI (HR1-SD = 1.13, 95% CI = 1.11 to 1.15, P = 0.357 for heterogeneity). Waist circumference residuals were more strongly associated with obesity-related cancer risk in men (HR1-SD = 1.09, 95% CI = 1.06 to 1.12) than in women (HR1-SD = 1.03, 95% CI = 1.02 to 1.05). Including an additional 6893 potential obesity-related cancers yielded similar patterns of associations. CONCLUSION(S): Waist circumference is a stronger risk factor than BMI for obesity-related cancer in men, conveying additional risk information, whereas this is less evident in women.