A Body Shape Index (ABSI), hip index, and risk of cancer in the UK Biobank cohort

Abdominal size is associated positively with the risk of some cancers but the influence of body mass index (BMI) and gluteofemoral size is unclear because waist and hip circumference are strongly correlated with BMI. We examined associations of 33 cancers with A Body Shape Index (ABSI) and hip index (HI), which are independent of BMI by design, and compared these with waist and hip circumference, using multivariable Cox proportional hazards models in UK Biobank. During a mean follow‐up of 7 years, 14,682 incident cancers were ascertained in 200,289 men and 12,965 cancers in 230,326 women. In men, ABSI was associated positively with cancers of the head and neck (hazard ratio HR = 1.14; 95% confidence interval 1.03–1.26 per one standard deviation increment), esophagus (adenocarcinoma, HR = 1.27; 1.12–1.44), gastric cardia (HR = 1.31; 1.07–1.61), colon (HR = 1.18; 1.10–1.26), rectum (HR = 1.13; 1.04–1.22), lung (adenocarcinoma, HR = 1.16; 1.03–1.30; squamous cell carcinoma [SCC], HR = 1.33; 1.17–1.52), and bladder (HR = 1.15; 1.04–1.27), while HI was associated inversely with cancers of the esophagus (adenocarcinoma, HR = 0.89; 0.79–1.00), gastric cardia (HR = 0.79; 0.65–0.96), colon (HR = 0.92; 0.86–0.98), liver (HR = 0.86; 0.75–0.98), and multiple myeloma (HR = 0.86; 0.75–1.00). In women, ABSI was associated positively with cancers of the head and neck (HR = 1.27; 1.10–1.48), esophagus (SCC, HR = 1.37; 1.07–1.76), colon (HR = 1.08; 1.01–1.16), lung (adenocarcinoma, HR = 1.17; 1.06–1.29; SCC, HR = 1.40; 1.20–1.63; small cell, HR = 1.39; 1.14–1.69), kidney (clear‐cell, HR = 1.25; 1.03–1.50), and post‐menopausal endometrium (HR = 1.11; 1.02–1.20), while HI was associated inversely with skin SCC (HR = 0.91; 0.83–0.99), post‐menopausal kidney cancer (HR = 0.77; 0.67–0.88), and post‐menopausal melanoma (HR = 0.90; 0.83–0.98). Unusually, ABSI was associated inversely with melanoma in men (HR = 0.89; 0.82–0.96) and pre‐menopausal women (HR = 0.77; 0.65–0.91). Waist and hip circumference reflected associations with BMI, when examined individually, and provided biased risk estimates, when combined with BMI. In conclusion, preferential positive associations of ABSI or inverse of HI with several major cancers indicate an important role of factors determining body shape in cancer development.