Obesity is a Major Risk Factor for Cancer in Asia-Pacific Populations
Overweight and obesity are now increasingly recognized as a major driver of cancers in the Western world. For example, recent estimates suggest that almost 1 in 3 cases of breast cancer are related to excess weight. A new study, published last month in Lancet Oncology, by Christine Parr and colleagues from the Asia-Pacific Cohort Studies Collaboration now confirms a significant association between excess weight and cancer mortality across this region of the world. The study includes data from over 400,000 participants from various populations from Asia and from Australia and New Zealand (ANZ). Compared to individuals with normal weight, a BMI of over 30 was associated with a 1.21-fold increased risk for for all-cause cancer (excluding lung and upper aerodigestive tract), 1.50-fold increased risk for colon cancer, 1.68-fold higher risk for rectum cancer, 1.63-fold higher risk for breast cancer in women 60 years or older, 2.62-fold higher risk for ovary cancer, 4.21-fold higher risk for for cervix cancer, 1.45-fold higher risk for prostate cancer, and 1.66-fold higher risk for for leukaemia. In contrast, excess weight did not appear to be associated with cancers of the oropharynx and larynx. Given the recent dramatic rise in the prevalence of overweight and obesity in the Asia-Pacific region, home to a considerable proportion of the world population, it can only be expected that cancer mortality will likely place a significant health burden in this region of the world. In light of the accumulating evidence that weight management and intentional weight loss can significantly reduce cancer mortality, this study calls for increased measures to both prevent and treat obesity in Asia-Pacific countries. AMS Edmonton, Alberta To follow me and post your comments on Facebook click here Parr CL, Batty GD, Lam TH, Barzi F, Fang X, Ho SC, Jee SH, Ansary-Moghaddam A, Jamrozik K, Ueshima H, Woodward M, Huxley RR, & on behalf of the Asia-Pacific Cohort Studies Collaboration (2010). Body-mass index and cancer mortality in the Asia-Pacific Cohort Studies Collaboration: pooled analyses of 424 519 participants. The lancet oncology, 11 (8), 741-752 PMID: 20594911
Obesity Increases Risk for Pancreatic Cancer?
While most people often think of excess weight as a risk factor for diabetes, heart disease, sleep apnea, or osteoarthritis, an accumulating body of evidence now points to obesity an important risk factor for cancers. While previous studies have shown the importance of obesity as a risk factor for breast and colon cancers, a study by Arsian and colleagues from the Pancreatic Cancer Cohort Consortium (PanScan) published in the latest issue of the Archives of Internal Medicine suggests that obesity may also be an important risk factor for pancreatic cancer. Using a nested case-control design that included 2170 cases and 2209 control subjects, the PanScan study found a positive 33% higher risk for pancreatic cancer in individuals with the highest compared to the lowest BMI quartile. This relationship was found both in men and women. When the researchers looked at abdominal obesity, the risk for pancreatic cancer in women in the highest quartile of waist circumference was almost twice that of women in the lowest quartile. These findings certainly provide strong support for a positive association between BMI and pancreatic cancer risk and suggest that centralized fat distribution may increase pancreatic cancer risk, especially in women. Given the observation that one of the most impressive impacts of bariatric surgery is an almost 60% reduction in cancer mortality, prevention of weight gain or successful weight management may certainly go a long way in reducing the risk of dying of this horrible disease. AMS Edmonton, Alberta p.s. Join my new Facebook page for more posts and links on obesity prevention and management Arslan AA, Helzlsouer KJ, Kooperberg C, Shu XO, Steplowski E, Bueno-de-Mesquita HB, Fuchs CS, Gross MD, Jacobs EJ, Lacroix AZ, Petersen GM, Stolzenberg-Solomon RZ, Zheng W, Albanes D, Amundadottir L, Bamlet WR, Barricarte A, Bingham SA, Boeing H, Boutron-Ruault MC, Buring JE, Chanock SJ, Clipp S, Gaziano JM, Giovannucci EL, Hankinson SE, Hartge P, Hoover RN, Hunter DJ, Hutchinson A, Jacobs KB, Kraft P, Lynch SM, Manjer J, Manson JE, McTiernan A, McWilliams RR, Mendelsohn JB, Michaud DS, Palli D, Rohan TE, Slimani N, Thomas G, Tjønneland A, Tobias GS, Trichopoulos D, Virtamo J, Wolpin BM, Yu K, Zeleniuch-Jacquotte A, Patel AV, & Pancreatic Cancer Cohort Consortium (PanScan) (2010). Anthropometric measures, body mass index, and pancreatic cancer: a pooled analysis from the Pancreatic Cancer Cohort Consortium (PanScan). Archives of internal medicine, 170 (9), 791-802 PMID: 20458087
Does Surviving Cancer Lead to Weight Gain?
While I am taking a brief break from clinics and other obligations (including daily blog posts), I will be reposting past articles, which I still believe to be relevant but may have escaped the attention of the 100s of new readers who have signed up in the past months. The following was first posted on 04/22/08 Yesterday’s big news was the study by Kerry Courneya, professor and Canada Research Chair in Physical Activity and Cancer at the University of Alberta, published in CANCER. I am not going to repeat the findings or the data here because this was nicely summarized by Sharon Kirkey from Canwest News Service in the Edmonton Journal. The bottom line is that cancer survivors are apparently not exercising more or eating healthier than everyone else, and are therefore at least as, if not even more, likely to develop obesity than the average Canadian. This is particularly true for survivors of breast and colon cancer, which are particularly likely to recur with lack of physical activity, unhealthy eating and weight gain. The dramatic impact of weight on cancer risk is perhaps best demonstrated by the observation that obesity surgery, which on average reduces body weight by 25%, results in an almost 60% reduction in cancer mortality! (see Adams et al. for an example of such a study). I guess it just goes to show that cancer survivors are no less susceptible to the consequences of our obesogenic environment, which certainly does not make weight control easy, even at the best of times. That is of course, unless there is something special about surviving cancer that makes you more likely to gain weight – an interesting hypothesis pursued by other researchers here at the University of Alberta. I can think of a number of reasons why surviving cancer could predispose to weight gain: “catch-up” fat, depression, “post-traumatic” stress, anxiety, susbtance abuse, “overfeeding”, immobility, medications, and perhaps a few others. Whatever the reasons, it looks like we may now need intervention programs to specifically address weight gain and obesity in cancer survivors? For one, educating cancer survivors about the links between excess weight and cancer would be a start. My sense is that most people still don’t fully appreciate the close link between obesity and cancer – all the more reason to promote healthy eating and active living for all. Obesity prevention (and treatment?) may well turn out to… Read More »
Weight Loss Prevents Cancer – Take Two
Regular leaders are already well aware of the increasing evidence that losing weight may be the most effective cancer prevention strategy, short of smoking cessation. Following close on the heels of a previous study on this topic, the latest issue of Lancet Oncology publishes another major study demonstrating the substantial effect of (surgical) weight loss on the incidence of cancers. In this study, Lars Sjöström and colleagues from the University of Gothenburg, Sweden, report on the incidence of cancers in the Swedish Obese Subjects Study: a prospective, controlled intervention trial of bariatric surgery. The SOS study started in 1987 and involved 2010 obese patients who underwent bariatric surgery and 2037 matched obese controls, who received conventional treatment. Over the 11-year course of the study, cancer follow-up rate was 99.9%. Patients who underwent bariatric surgery had a sustained mean weight reduction of 19.9 kg, whereas the mean weight change in controls was a gain of 1.3 kg. The number of first-time cancers after inclusion was lower in the surgery group (n=117) than in the control group (n=169), a risk reduction of 33%. There were, however, important sex differences in this effect. While in women, the risk of first-time cancers was reduced by 42% (79 vs. 130), there was no difference in cancer incidence with weight loss in men (39 vs. 38). The results were similar even when cancer cases in the first 3 years of observation were excluded. Thus, this study once again confirms the substantial effect of (surgical) weight loss on the incidence of cancers (at least in women). These finding perhaps give a whole new meaning to “Running for the Cure”. AMS Duchesnay, Quebec
Gastric Bypass Surgery Cuts Cancer Mortality in Half
For anyone still skeptical about the tremendous benefit of bariatric surgery for severe obesity in reducing cancer mortality, here is a new study by Ted Adams and colleagues from the University of Utah, published in the latest issue of OBESITY. Adams and colleagues examined cancer incidence and mortality data through 2007 from the Utah Cancer Registry (UCR) in 6,596 Utah patients who had gastric bypass for severe obesity (1984-2002) and 9,442 severely obese persons who had applied for Utah Driver’s Licenses (1984-2002). Over a 24-year follow-up period (mean 12.5 years), total cancer incidence was almost 25% lower in the surgical group compared to controls, this difference being largely attributable to a decreased incidence of cancers at advanced stages in the surgical group. Overall cancer mortality was 46% lower in the surgery group compared to controls. Interestingly, while the reduction in new cancers was largely limited to cancers known to be related to obesity (e.g. breast, colon, etc.), the reduction in mortality was from all cancers. This analysis is consistent with previous reports on up to 60% reduction in cancer mortality in bariatric surgical patients. It appears that short of smoking cessation, bariatric surgery is perhaps the most effective measure for prevention of cancer and lowering cancer mortality in modern medicine. AMS Toronto, Ontario (from the meeting on Building Authentic Trust to Address the Epidemic of Obesity and Chronic Diseases)
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