Obesity has strong association with increased incidence of, and premature mortality from, some types of cancer1. However, a study by the World Cancer Research Fund (WCRF) report also highlighted the lack of evidence regarding the association of cancer with other markers of adiposity (i.e. central adiposity and body fat). Although previous studies have reported the association of several cancer sites with different markers of adiposity, most of these studies have been conducted in Asian populations. Lee et al. reported the associations of 18 cancers with waist circumference (WC) in 22.9 million Korean adults2. Similarly, Wang et al. reported the associations of four markers of adiposity including BMI, WC, waist-to-hip ratio (WHR), and body fat percentage (BF%) with 15 cancers in the China Kadoorie Biobank3. To address these limitations, this study by Parra-Soto et al. used data from the UK Biobank cohort to investigate the associations of six adiposity markers with incidence and mortality from 24 cancers by accounting for potential non-linear associations4.
UK Biobank recruited more than 500,000 participants (aged 37–73 years, 56.3% were women) between 2006 and 20105. Participants with a prevalent cancer diagnosis at baseline, with missing data, and those that were classified as underweight were excluded from the study. The outcomes defined for this study were incidence and mortality of overall cancer and 24 specific cancers. Of the 24 cancers, 17 were relevant to both men and women, two were specific to men (testicular and prostate cancer), and five were specific to women (breast, endometrium, uterine, cervix and ovary). The parameters evaluated were adiposity-related markers, including BMI, WC, WHR, waist-to-height ratio (WHtR), hip circumference (HC), and BF%. The covariates were sociodemographic factors (age, ethnicity, education, and Townsend deprivation), smoking status, dietary intake (red meat, processed meat, fruit and vegetables, oily fish, and alcohol), physical activity, and sedentary behavior. Additional cancer-specific covariates for women-related cancer were hormonal replacement, ages at first live birth, last live birth, and at menarche. Additionally, sun exposure was added as a covariate for melanoma cancer. For lung, esophageal, and oral cancer, the analysis wasrestricted to participants that never smoked.
Higher levels of adipositywere associated in a linear manner with a higher incidence of liver, kidney, stomach, pancreatic, bladder, gallbladder, colorectal cancer, endometrial, uterine, and breast (in postmenopausal women) cancer.These findings corroborate previous studies that demonstrated that adult adiposity (assessed using BMI) is associated with higher risk of esophageal, pancreatic, liver, colorectal, postmenopausal breast, and endometrial cancers6. On the other hand, this study did not find evidence for an association between BMI (and any other markers of adiposity) and ovarian cancer. Interestingly, they also did not find a significant association between adiposity and lung cancer in never smokers.
There is convincing evidence that greater adiposity is associated with increased risk of colorectal cancer, assessed mainly as BMI in prospective cohort studies7. This study corroborates these findings and adds novel evidence that other adiposity markers are also consistently associated with an increased risk of colorectal cancer. The authors also observed that all adiposity markers were positively associated with higher liver cancer risk and an increased risk of breast cancer. But this association appeared to occur in postmenopausal women only. Adiposity, regardless of the marker used, was associated with an increased risk of 10 cancer sites. However, no evidence was found that the use of other adiposity markers, such as central adiposity or body fat, improves the prediction ability for cancer risk.
According to the authors “ The findings of this study have important clinical implications. First, it provides evidence that central (waist and hip circumference) and overall adiposity (BMI and BF%) markers produced similar relative risk estimates. Therefore, the use of BMI, a simple and low-cost measurement, is adequate for clinical screening in terms of cancer risk, and there is no advantage in using more complicated or more expensive measures such as WC or BF%. We also found that a significant proportion of cancers could be prevented by reducing obesity, especially liver and kidney cancer in men and endometrial and uterine cancer in women.”
References
- Mokdad AH, Ford ES, Bowman BA, Dietz WH, Vinicor F, Bales VS, et al. Prevalence of obesity, diabetes, and obesity-related health risk factors, 2001. Jama-J Am Med Assoc. 2003;289(1):76–79.
- Lee KR, Seo MH, Do Han K, Jung J, Hwang IC. Waist circumference and risk of 23 site-specific cancers: a population-based cohort study of Korean adults. Br J Cancer. 2018;119(8):1018–1027.
- Wang L, Jin G, Yu C, Lv J, Guo Y, Bian Z, et al. Cancer incidence in relation to body fatness among 0.5 million men and women: findings from the China Kadoorie Biobank. Int J Cancer. 2020;146(4):987–998.
- Parra-Soto S, Cowley ES, Rezende LFM, et al. Associations of six adiposity-related markers with incidence and mortality from 24 cancers-findings from the UK Biobank prospective cohort study. BMC Med. 2021;19(1):7.
- Collins R. What makes UK Biobank special? Lancet. 2012;379(9822):1173–1174.
- Stolzenberg-Solomon RZ, Schairer C, Moore S, Hollenbeck A, Silverman DT. Lifetime adiposity and risk of pancreatic cancer in the NIH-AARP Diet and Health Study cohort. Am J Clin Nutr. 2013;98(4):1057–1065
- Johnson CM, Wei C, Ensor JE, Smolenski DJ, Amos CI, Levin B, et al. Meta-analyses of colorectal cancer risk factors. Cancer Causes Control. 2013;24(6):1207–1222
