Traditional and Novel Adiposity Indicators and Pancreatic Cancer Risk: Findings from the UK Women’s Cohort Study

SIMPLE SUMMARY: Pancreatic cancer has a poor survival rate and its modifiable risks are poorly understood. We investigated the association between both traditional (BMI, waist and hip circumference and waist–hip ratio) and novel (standard UK clothing sizes) adiposity indicators as predictors of pancreatic cancer risk among women enrolled in the UK women’s cohort study (UKWCS). When adjusted for known confounders like age, education, smoking and physical activity, hip circumference and skirt size were both significant predictors of pancreatic cancer risk in the median follow-up of approximately 19 years. BMI became a significant predictor of pancreatic cancer risk when potential latent cases of pancreatic cancer were excluded from the analysis. Thus, adiposity indicators, specifically hip circumference and standard skirt size, are useful to predict pancreatic cancer among women and should therefore be routinely documented in both national surveys and epidemiological studies. ABSTRACT: (1) Background: We studied the association of both conventional (BMI, waist and hip circumference and waist–hip ratio) and novel (UK clothing sizes) obesity indices with pancreatic cancer risk in the UK women’s cohort study (UKWCS). (2) Methods: The UKWCS recruited 35,792 women from England, Wales and Scotland from 1995 to 1998. Cancer diagnosis and death information were obtained from the National Health Service (NHS) Central Register. Cox’s proportional hazards regression was used to evaluate the association between baseline obesity indicators and pancreatic cancer risk. (3) Results: This analysis included 35,364 participants with a median follow-up of 19.3 years. During the 654,566 person-years follow up, there were 136 incident pancreatic cancer cases. After adjustments for age, smoking, education and physical activity, each centimetre increase in hip circumference (HR: 1.03, 95% CI: 1.01–1.05, p = 0.009) and each size increase in skirt size (HR: 1.12, 95% CI: 1.02–1.23, p = 0.041) at baseline increased pancreatic cancer risk. Baseline BMI became a significant predictor of pancreatic cancer risk (HR: 1.04, 95% CI: 1.00–1.08, p = 0.050) when latent pancreatic cancer cases were removed. Only baseline hip circumference was associated with pancreatic cancer risk (HR: 1.03, 95% CI: 1.00–1.05, p = 0.017) when participants with diabetes at baseline were excluded to control for reverse causality. (4) Conclusion: Hip circumference and skirt size were significant predictors of pancreatic cancer risk in the primary analysis. Thus, hip circumference is useful to assess body shape relationships. Additionally, standard skirt sizes offer an economical and objective alternative to conventional obesity indices for evaluating pancreatic cancer risk in women.