Obesity and Cancer in Iowa Facts & Figures Two-thirds of adult Iowans are either overweight or obese 18% 28% 32% Percentage increase in the number of Iowans who were overweight and obese between 1998 and 2013 Percentage of Iowa high school students who are overweight or obese Percentage of Iowa children ages 2-5 who participated in the Women, Infants, and Children supplemental nutrition program who are overweight or obese
Obesity is an important cause of unnecessary suffering and death from many types of cancer. An estimated 1 of every 3 cancer deaths in the United States is linked to excess body weight, poor nutrition, and physical inactivity. These factors are all related and may all contribute to cancer risk, but body weight has the strongest evidence linking it to cancer. Excess body weight may contribute to as many as 1 out of 5 cancer-related deaths. What is obesity? Obesity is a condition in which a person has an abnormally high and unhealthy proportion of body fat. To measure obesity, researchers commonly use a scale known as the body mass index (BMI). BMI is calculated by dividing a person s weight (in kilograms) by their height (in meters) squared. BMI provides a more accurate measure of overweight or obesity than weight alone. Guidelines established by the National Institutes of Health categorize adults age 20 and older as follows based on their BMI: BMI BMI Categories Below 18.5 Underweight 18.5 to 24.9 Normal 25.0 to 29.0 Overweight 30.0 and above Obese Compared with people of normal weight, those who are overweight or obese are at greater risk for many diseases, including diabetes, high blood pressure, cardiovascular diseases, stroke, and certain cancers. A 1% reduction in BMI among adults in the US could prevent 100,000 cancer cases by 2030. The National Cancer Institute estimates that if current trends persist, obesity could lead to an additional 500,000 cancer cases in the US by 2030. Trends in Obesity-related Cancers During the past two decades, there has been a steady decline in the overall number of new cancer cases in the US among adults in most racial and ethnic groups. However, for several cancers, including pancreatic, kidney, and esophageal cancers, rates have increased. This increase can be attributed, in part, to excess weight and physical inactivity, and can adversely affect quality of life and may worsen prognosis for cancer patients. How does obesity increase cancer risk? There are several ways that obesity may contribute to an increased risk of cancer: Fat tissue produces estrogen, and high estrogen levels are associated with an increased risk of certain types of cancer. Fat cells produce other hormones that can affect cell growth. Obese people have higher levels of blood insulin, which may promote cancer development. Obese people often have chronic low-level inflammation, which is also associated with cancer risk. What cancers are likely in overweight populations? Overweight and obesity are clearly associated with an increased risk for developing many cancers, including, but not limited to, cancers of the: Breast (after menopause) Colon and rectum Endometrium (lining of the uterus) Esophagus Kidney Pancreas Prevalance* of Self-reported Obesity Among US Adults by State, BRFSS, 2013 * Prevalence estimates reflect BRFSS methodological changes started in 2011. These estimates should not be compared to prevalence estimates before 2011. AK WA OR NV CA ID UT AZ MT WY CO NM ND SD NE KS OK TX MN WI IA IL MO AR MS LA MI OH IN WV KY TN SC AL GA FL NY PA VA NC VT ME NH MA RI CT NJ DE MD DC 15% - <20% 20% - <25% 25% - <30% 30% - <35% HI >35% Source: Behavioral Risk Factor Surveillance System, CDC.
Overweight or Obese, National and Iowa, 1998-2013 70 65 Percent 60 Iowa 55 National 50 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 Year Source: BRFSS. Note: National = median of 50 states and D.C. Break in trend between 2010 and 2011 due to methodological change. Overweight and obesity are likely associated with increased risk of the following cancers: Cervical & ovarian Gallbladder Liver Multiple myeloma Non-Hodgkin lymphoma Aggressive prostate cancer Obesity and Postmenopausal Breast Cancer Many studies have shown that overweight and obesity are associated with a modest increase in the risk of postmenopausal breast cancer. This higher risk is seen mainly in women who have never used menopausal hormone therapy (MHT) and for tumors that express both estrogen and progesterone receptors. By contrast, overweight and obesity have been found to be associated with a reduced risk of premenopausal breast cancer in some studies. The relationship between obesity and breast cancer may be affected by the stage of life in which a woman gains weight and becomes obese. Epidemiologists are actively working to address this question. Weight gain during adult life, most often from about age 18 to between the ages of 50 and 60, has been consistently associated with a risk of breast cancer after menopause. Obesity and Endometrium Cancer Endometrial cancer is a cancer of the lining of the uterus. Overweight and obesity have been consistently associated with endometrial cancer. Obese and overweight women have two to four times the risk of developing this type of cancer than women of a normal weight, regardless of menopausal status. Many studies have also found that the risk of endometrial cancer increases with increasing weight gain in adulthood, particularly among women who have never used MHT. Obesity and excess abdominal fat increase the risk of endometrial cancer, most likely by increasing the amount of estrogen in the body. Estrogen exposure is a strong risk factor for endometrial cancer. In Iowa, from 2006-2011, an average of 560 cases of endometrial cancer were diagnosed and 100 women died from the disease each year. The rate of new endometrial cancer cases in the state was higher than the nationally reported rate. Overweight or Obese by Gender, Race, and Age, Iowa, 2013 80 60 Obesity and Colon and Rectum Cancer Among men, a higher BMI is strongly associated with an increased risk of colorectal cancer. The distribution of body fat appears to be an important factor, with abdominal obesity which can be measured by waist circumference showing the strongest association with colon cancer risk. An association between BMI and waist circumference is also seen in women, but is weaker. Use of MHT may modify the association in postmenopausal women. Percent 40 20 0 Male Female Hispanic/ nonwhite Non- Hispanic white Gender, Race, Age Source: Iowa Behavioral Risk Factor Surveillance System 2013. 18-24 years 25+ years
American Cancer Society Guidelines on Nutrition and Physical Activity for Cancer Prevention The American Cancer Society guidelines for nutrition and physical activity include four recommendations for individual choices that may help reduce cancer risk: Achieve and maintain a healthy weight throughout life. Be as lean as possible throughout life without being underweight. Avoid excess weight gain at all ages. For those who are overweight or obese, losing even a small amount of weight has health benefits and is a good place to start. Get regular physical activity and limit intake of high-calorie foods and drinks as keys to help maintain a healthy weight. Be physically active. Adults: Engage in at least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity physical activity each week, or an equivalent combination, preferably spread throughout the week. Children and adolescents: Engage in at least 60 minutes of moderate- or vigorous-intensity activity each day, with vigorous activity at least three days each week. Limit sedentary behavior such as sitting, lying down, watching TV, and other forms of screen-based entertainment. Doing some physical activity above usual activities, no matter what the level of activity, can have many health benefits. Eat a healthy diet, with an emphasis on plant foods. Choose foods and drinks in amounts that help you get to and maintain a healthy weight. Limit how much processed meat and red meat you eat. Eat at least 2½ cups of vegetables and fruits each day. Choose whole grains instead of refined grain products. If you drink alcohol, limit your intake. Drink no more than one alcoholic beverage per day for women or two per day for men. Recommendations for Community Action Although many Iowans would like to adopt a healthy lifestyle, many encounter barriers that make it difficult to do so. These guidelines stress the importance of public, private, and community organizations working together at national, state, and local levels to apply policy and environmental changes that: Increase access to affordable, healthy foods in communities, places of work, and schools, and decrease access to and marketing of foods and drinks of low nutritional value, particularly to youth. Provide safe, enjoyable, and accessible environments for physical activity in schools and workplaces, and for transportation and recreation in communities.
Obesity and Esophageal Cancer Overweight and obese people are about twice as likely as individuals of a normal weight to develop a type of esophageal cancer called esophageal adenocarcinoma. Most studies have observed no increased risk, or even a decline in risk, with obesity for the other major type of esophageal cancer, squamous cell cancer. The reasons why obesity may increase the risk of esophageal adenocarcinoma are not well understood. However, overweight and obese people are more likely than people of a normal weight to have a history of gastroesophageal reflux disease or Barrett esophagus, which are associated with an increased risk of esophageal adenocarcinoma. It is possible that obesity exacerbates the esophageal inflammation that is associated with these conditions. In Iowa, from 2006-2011, an average of 190 cases of esophageal cancer were diagnosed and 175 deaths resulted from this cancer each year. Also, almost 60% of esophageal cancer diagnoses and 65% of esophageal cancer deaths occurred among adults age 65 and older in the state. Obesity and Kidney Cancer Obesity has been consistently associated with renal cell cancer, the most common form of kidney cancer in both men and women. High blood pressure is a known risk factor, but the relationship between obesity and kidney cancer is independent of blood pressure status. High levels of insulin may also play a role in the development of the disease. In 2014, kidney cancer is projected to be the seventh most commonly diagnosed cancer in men and the ninth most commonly diagnosed cancer in women in Iowa. An average of 605 cases and 170 deaths occurred from kidney cancer in Iowa each year from 2006-2011. Also, about 55% of kidney cancer diagnoses and 70% of kidney cancer deaths occurred among adults age 65 years or older. Iowa men were two times more likely to be diagnosed with kidney cancer as compared to Iowa women. Obesity and Pancreatic Cancer Obesity has also been fairly consistently linked to a slightly increased risk of pancreatic cancer. Pancreatic cancer is the fourth leading cause of cancer death in Iowa for both men and women. From 2006-2011, an average of 435 cases were diagnosed and 380 deaths occurred each year in the state. Pancreatic cancer is extremely rare in those under 50 years of age 70% of diagnoses and 70% of deaths occurred in adults age 65 or older in Iowa; rates of new cases were about 35% higher among males than females. Also, African American men and women in Iowa have the highest rates of new pancreatic cancer cases and deaths, mirroring the national trend. 2014 American Cancer Society, Inc. No. 030752