Obesity and risk of pancreatic cancer among postmenopausal women: the Women's Health Initiative (United States)

Abstract

A total of 138 503 women in the Women's Health Initiative in the United States were followed (for an average of 7.7 years) through 12 September 2005 to examine obesity, especially central obesity in relation to pancreatic cancer (n ¼ 251). Women in the highest quintile of waist-to-hip ratio had 70% (95% confidence interval 10 -160%) excess risk of pancreatic cancer compared with women in the lowest quintile. (Ekbom and Hunter, 2007). Besides tobacco smoking and chronic pancreatitis (Lowenfels et al, 1999), little is known of its aetiology, but recently, increasing evidence has suggested that obesity is a risk factor (Berrington de Gonzalez et al, 2003;Larsson et al, 2007). However, in most studies, the association seems to be weaker in women -who tend to gain weight more peripherally -than in men, suggesting that central adiposity may be a stronger risk factor for pancreatic cancer than body mass index (BMI). Few studies have investigated this aspect and the findings are inconsistent (Larsson et al, 2005;Sinner et al, 2005;Ansary-Moghaddam et al, 2006;Berrington de Gonzalez et al, 2006).We have used the large prospective Women's Health Initiative (WHI) study, with measured anthropometric factors, including hip and waist circumference, to examine the relationship between BMI, central adiposity, and pancreatic cancer risk. MATERIALS AND METHODS Women's Health InitiativeThe WHI, an ongoing, ethnically and geographically diverse, multi-centre clinical trial (CT) and observational study (OS), was designed to address some of the major causes of morbidity and mortality in postmenopausal women. Briefly, a total of 161 808 women aged 50 -79 years were recruited at 40 clinical centres throughout the United States from 1 September 1993 through 1998. The WHI includes three overlapping CT components (hormone trial, dietary modification trial, and calcium/vitamin D supplementation trial) and an OS. All participants in WHI gave informed consent and were followed prospectively. Details of the scientific rationale, eligibility requirements and baseline characteristics of the participants in the WHI have been published elsewhere (Hays et al, 2003;Jackson et al, 2003;Langer et al, 2003;Ritenbaugh et al, 2003;Stefanick et al, 2003).The following participants were excluded from the original cohort of 161 808 : 14 849 with a history of cancer (except nonmelanoma skin cancer) at baseline, 668 with no follow-up, 7491 with missing values of main exposures and confounders (including weight, height, waist circumference, hip circumference, smoking, and diabetes), and 297 (0.18%) with waist-to-hip ratio (WHR) values of beyond 4 s.d. (WHRo0.4 or WHR41.2), leaving 138 503 women for analysis.All exposures in our analyses were collected at baseline for all participants. During the baseline clinical visit, trained and certified staff performed anthropometric measurements, including height, weight, hip and waist circumferences, and blood pressure. Body mass index was calculated as weight in kilograms divided by the square of height in metres. Wa...

Body mass index, effect modifiers, and risk of pancreatic cancer: a pooled study of seven prospective cohorts

“…We might not have captured critical windows of lifetime weight change that may confer a higher risk of pancreatic cancer, particularly among former smokers. Central adiposity may be a more relevant measure than BMI for risk of pancreatic cancer [8, 44, 45, 50–52]. AARP, BCDDP, and SWHS collected waist and hip circumference information, but the number of cases in the BCDDP or SWHS cohorts with such data was small (<60) so that the associations with central adiposity would be driven by the AARP study, for which a positive association was previously reported for women but not for men [8].…”

The complexities of obesity and diabetes with the development and progression of pancreatic cancer

“…This study examined obesity, especially central obesity, in relation to PC (n=251) for the duration of an average of 7.7 years of follow-up [40]. The results show that women in the highest quintile of waist-to-hip ratio have a 70 percent (95% CI, 10–160%) greater risk of PC compared with women in the lowest quintile.…”

Body mass index, abdominal fatness and pancreatic cancer risk: a systematic review and non-linear dose–response meta-analysis of prospective studies

“…Abdominal obesity may be more strongly associated with insulin resistance than peripheral obesity (4), but there have been relatively few studies of waist circumference and waist-to-hip ratio as measures of abdominal fatness in relation to pancreatic cancer risk. A number of additional large cohort studies have been published since the WCRF/AICR report from 2007 (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17), thus, we conducted an updated meta-analysis of BMI, waist circumference and waist-to-hip ratio and pancreatic cancer risk with the aim to clarify whether body fatness is associated with pancreatic cancer in both men and women and in European and Asian populations as well. In addition, we wanted to clarify the dose-response relationship between BMI, waist circumference and waist-to-hip ratio and pancreatic cancer risk by conducting nonlinear dose-response analyses and by restricting the analysis to studies among non smokers or never smokers.…”