Annals of Behavioral Science and Medical Education 2013, Vol. 19, No. 1, 27–32

©2013 by the Association for the Behavioral Sciences and Medical Education 1075–1211/13

Body Mass Index and Perception of Cancer Risk: An Opportunity for Behavioral Education? Julie M. Kapp, M.P.H., Ph.D. University of Missouri

Walton Sumner, M.D. Washington University School of Medicine

Objective: Because healthy lifestyle has been associated with reduced risk of certain cancers, we examined differences in cancer-risk and weight-related perceptions by body mass index (BMI). Methods: We used the 2007 Health Information National Trends Survey (HINTS) data from 2,112 respondents aged 40-75 years. Based on self-reported BMI, we compared obese, overweight, and normal/underweight respondents’ perceptions of personal cancer risk and weight-related beliefs. Results: One-fifth of obese and overweight and one-seventh of normal weight respondents perceived a high personal risk of developing cancer. Over one-fourth of overweight and obese and one-fifth of normal weight respondents lacked confidence in their ability to manage their health. Most respondents reported having health insurance and a usual provider. Conclusions: Obese respondents were more likely to perceive a higher personal risk of cancer. Results may suggest an opportunity for focused behavioral education that might reduce both obesity and cancer risk. Implications for health care provider education: Behavior change is exceedingly difficult to achieve and maintain. This report provides background on how people who are overweight perceive themselves and their risks for health complications, in this case, cancer. Good understanding of “human nature” allows the clinician to craft an intervention that has a better chance of being successful. We present the FRAMES paradigm that students and practitioners alike might find an easily remembered guide to providing patient advice and encouragement. Key words: Health Information National Trends Survey, HINTS, body mass index, BMI, cancer risk perception, physician education, medical student education

Introduction

body weight for some organ sites, such as colon, breast,4 endometrium, esophagus, and kidney.5 Fortunately, there is accumulating evidence that many cancer cases could be prevented.6,7 More specifically, lifestyle has been associated with cancer incidence,8 and evidence suggests that more than 50% of cancers can be prevented.9 Obesity is estimated to account for 15% of cancer cases, physical inactivity for 5%, and poor diet for 10-25%.6 Fatalistic beliefs about cancer prevention have been associated with a lower likelihood of preventive behaviors, such as weekly exercise, being a nonsmoker, and daily fruit and vegetable consumption.10 Nearly half of respondents from the 2003 Health Information National Trends Survey (HINTS 2003) agreed that it seems almost everything causes cancer.10

Approximately half of all premature deaths in the US are attributed to largely preventable behaviors and exposures, such as tobacco use, poor diet, physical inactivity, and alcohol consumption.1-3 Many risk factors for leading causes of death (heart disease, cancer, and cerebrovascular disease)1,2 are modifiable. Poor diet and inactivity are known risk factors for heart disease, and evidence is mounting that cancer risk is related to excess

Julie M. Kapp, M.P.H., Ph.D. Department of of Educational Psychology, Research and Evaluation College of Education University of Missouri-St. Louis 407 Marillac Hall One University Blvd. St. Louis, MO 63121-4400 [email protected]

In the context of the current obesity epidemic, healthy eating, exercise, and weight management could benefit many patients through reduced risks of cancer and cardiovascular disease, and by improving quality of life. Unfortunately, opportunities to educate overweight and obese patients are often missed. A generational shift in social norms suggests a decline in persons 27

BODY MASS INDEX AND PERCEPTION OF CANCER RISK who self-classify as overweight compared to previous decades.11 Fewer than 50% of primary care physicians consistently provide diet and weight control counseling for their adult patients with weight-related diseases.12,13 In 2011, the US Preventive Services Task Force (USPSTF) identified moderate- to low-intensity counseling for obesity as among the priorities for research in behavioral interventions,14 and in 2012, recommended referring adult patients with a BMI of ≥30 kg/m2 for management of obesity.15

confident); extent to which you believe obesity is inherited (a lot; some; a little; not at all); and extent to which you believe obesity is caused by overeating and not exercising (a lot; some; a little/not at all). Analysis We used frequencies and weighted percentages to describe the sample by various respondent characteristics, overall and by BMI categories. We used frequencies and weighted percentages to describe cancer risk perceptions and weight-related beliefs, overall and by BMI categories. We suggest potentially meaningful differences between groups based on a ≥5% difference in percentages, as the use of conventional tests of statistical significance with these sample sizes may identify differences that are statistically significant but not clinically meaningful. (A chi-square analysis found that all comparisons in Tables 2 and 3 were significant at p<0.0001). We used SAS software version 9.2 to account for the complex sampling design.

Therefore, as a preliminary study for hypothesis generation, we analyzed national survey data to describe differences in weightrelated and cancer-risk beliefs between obese, overweight, and normal/underweight adults.

Methods Sample We used the HINTS 2007 random digit-dialed telephone survey data, a nationally representative sample of non-institutionalized US adults age 18 and older. Further details about the study, design, and methods, including sampling weights, can be found at http://hints.cancer.gov/. Briefly, the sampling weights are population-based, reflecting the demographic distribution of adults in the US in 2007; thus, when applied, the weights enhance the ability of these data to represent the national population.

Results Study sample Table 1 provides respondent characteristics. About two thirds of the respondents were classified as overweight or obese. Most respondents reported having health insurance, a usual provider, a family history of cancer, and at least two health care visits in the past 12 months.

From a total of 4,092 respondents, we selected those between the ages of 40 and 75 years (inclusive) who reported no personal history of cancer, and who had height and weight data for BMI (excluding n=340). Our final sample included 2,112 respondents.

Cancer-Risk Perceptions Respondents were split on their belief that cancer is most often caused by a person’s behavior or lifestyle (Table 2). About a fourth of respondents agreed there is not much one can do to lower one’s chances of getting cancer, and about a third indicated physical activity or exercise makes no difference in the chances of cancer. The only substantive difference in cancer-risk perceptions across BMI categories was in the likelihood of developing cancer. Obese respondents (19.7%) were more likely to report a high perceived likelihood of developing cancer than normal/underweight respondents (13.8%).

Data management We used standard BMI categories, grouped as follows: obese (≥30 kg/m2), overweight (25-<30 kg/m2), and normal/ underweight (<25 kg/m2). We examined the following variables of perceptions of cancer risk: perceived likelihood of developing cancer (very/somewhat low; moderate; very/somewhat high); frequency of cancer worry (often/all the time; sometimes; rarely/never); agreement cancer is caused by lifestyle (strongly/somewhat agree; strongly/somewhat disagree); agreement there is not much you can do to lower cancer chances (strongly/somewhat agree; strongly/somewhat disagree); and belief that physical activity or exercise decreases or makes no difference in the chance of getting cancer. As only 10 respondents indicated exercise increases the chance of getting some types of cancer, we set these to missing as the cell size would not be large enough for analysis.

Weight-Related Perceptions As expected, obese respondents were more likely to report being overweight compared to those underweight/normal or overweight and to report trying to lose weight in the past 12 months (Table 3). Obese respondents were less likely to report confidence in their ability to take care of their health and were more likely to consider obesity to be inherited than normal/underweight respondents. No differences were found across BMI categories in the belief that obesity is caused by overeating and not exercising.

We examined the following variables of weight-related perceptions: self-perceived weight (overweight; slightly overweight; just right; underweight/slightly underweight); tried to lose weight in the past 12 months (yes; no); how confident you are about the ability to take good care of your health (completely/very confident; somewhat/a little/not at all

Discussion To our knowledge, this is the first study to examine associations between BMI and cancer-risk perceptions in a large, population-based US sample; related studies have been conducted 28

KAPP, SUMNER Table 1

2007 HINTS Respondent Characteristics Aged 40-75 with Body Mass Index Data and No Personal History of Cancer*

BMI Group Underweight / Normal Overweight Obese Age Groups 40-49 50-59 60-75 Gender Male Female Health insurance Yes No Employment Yes No Married Yes No Hispanic Yes No Race Black White Other Education Less than high school High school graduate or GED Some college or technical school College graduate or post graduate Annual household income <$20,000 $20,000-<$35,000 $35,000-<$50,000 $50,000-<$75,000 ≥$75,000 Usual provider Yes No Number of health care visits in past 12 months 0 1 2 3+ Family history of any cancer Yes No * Frequencies and weighted percentages; random digit-dialed data

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N=2,112

%

725 778 609

32.6 36.7 30.8

560 683 869

39.7 33.7 26.6

872 1240

50.0 50.0

1897 212

86.5 13.5

1134 955

61.1 38.9

1310 792

65.6 34.4

141 1954

8.4 91.6

168 1742 195

12.4 77.0 10.6

163 529 623 787

11.9 28.5 32.1 27.6

245 284 227 346 654

13.5 16.0 12.2 20.9 37.4

1782 327

80.1 19.9

210 325 415 1156

13.1 16.8 20.0 50.1

1559 538

71.9 28.1

BODY MASS INDEX AND PERCEPTION OF CANCER RISK Table 2

Cancer-Risk Perceptions, Overall and by Body Mass Index Category (2007 HINTS Respondents Aged 40-75 Years)* Overall

Perceived Likelihood of Developing Cancer Low Moderate High How Often Worry about Getting Cancer Rarely / Never Sometimes Often / All the time Cancer is Most Often Caused by a Person’s Behavior or Lifestyle Strongly Agree / Agree Strongly Disagree / Disagree There’s Not Much to Do to Lower Chances of Getting Cancer Strongly Agree / Agree Strongly Disagree / Disagree Does Physical Activity or Exercise … Decrease the Chances of Cancer Make No Difference

Underweight/ Normal

Overweight

Obese

N (%)

N (%)

N (%)

N (%)

861 (42.6) 790 (40.0) 343 (17.4)

320 (45.1) 269 (41.2) 96 (13.8)

319 (43.6) 285 (37.8) 132 (18.6)

222 (38.8) 236 (41.5) 115 (19.7)

1241 (58.7) 726 (34.2) 141 (7.1)

411 (56.7) 261 (36.4) 50 (6.9)

472 (60.4) 267 (35.0) 39 (4.6)

358 (58.9) 198 (30.9) 52 (10.2)

1034 (49.0) 1059 (51.0)

369 (51.7) 348 (48.3)

369 (48.6) 402 (51.4)

296 (46.8) 309 (53.2)

460 (24.5) 1634 (75.5)

127 (23.0) 591 (77.0)

181 (24.3) 592 (75.7)

152 (26.3) 451 (73.7)

1339 (66.3) 654 (33.7)

485 (69.3) 206 (30.7)

475 (64.6) 256 (35.4)

379 (65.0) 192 (35.0)

*Frequencies and weighted percentages; random digit-dialed data

Table 3

Weight-Related Perceptions, Overall and by Body Mass Index Category (2007 HINTS Respondents Aged 40-75 Years)* Overall

Right now feel weight is Overweight Slightly overweight Just about right Underweight/Slightly underweight Tried to lose weight in past 12 months Yes No Confidence in ability to take care of health Completely/very Somewhat/a little/not at all Extent believe obesity is inherited A lot Some A little Not at all Extent believe obesity is caused by overeating and not exercising A lot Some A little / not at all

Underweight/ Normal

Overweight

Obese

N (%)

N (%)

N (%)

N (%)

699 (32.2) 735 (34.9) 613 (29.3) 65 (3.7)

35 (4.5) 182 (23.6) 449 (61.6) 59 (10.4)

214 (24.9) 413 (52.4) 146 (21.9) 5 (0.8)

450 (70.2) 140 (25.8) 18 (4.0) 1 (0.07)

1185 (55.0) 926 (45.0)

251 (31.8) 473 (68.2)

472 (58.3) 306 (41.7)

462 (75.7) 147 (24.3)

1607 (74.9) 501 (25.2)

577 (78.4) 145 (21.6)

586 (73.8) 191 (26.2)

444 (72.4) 165 (27.6)

460 (22.0) 1062 (50.3) 394 (18.6) 170 (9.1)

120 (17.2) 368 (48.7) 160 (24.3) 62 (9.9)

165 (21.7) 393 (50.8) 143 (17.4) 69 (10.2)

175 (27.4) 301 (51.3) 91 (14.2) 39 (7.1)

1623 (77.1) 407 (19.4) 70 (3.5)

554 (76.9) 146 (21.0) 18 (2.2)

615 (78.4) 135 (17.8) 24 (3.8)

454 (76.0) 126 (19.5) 28 (4.5)

* Frequencies and weighted percentages; random digit-dialed data

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KAPP, SUMNER in Europe.16,17 These nationally representative data suggest that obese adults are more likely than normal/underweight adults to perceive a high risk of developing cancer. However, they are no more likely to worry about cancer, or to believe that healthy behaviors reduce the risk of cancer.

While there is a vast literature on the “how” of exercise, such as intensity and duration, physicians also need to consistently address with patients the “why” and “whether” they are making progress. For example, patients could record daily caloric, protein, and fiber intake (a diet high in protein and fiber can help one feel “fuller”), exercise, and their thoughts on why some days were particularly challenging. Regarding diet, an important question is why the patient overeats. Eating as self-medication for depression implies an opportunity to treat depression with a more effective intervention, such as cognitive behavioral therapy. Recommending patients record their daily weight loss efforts, and bring those records to their next visit, helps the patient stay accountable and provides data-driven talking points tailored to that patient.

As expected, obese adults generally recognize they are overweight, and they have tried to lose weight in the past 12 months. In post hoc analyses, among those who have tried to lose weight, obese respondents were more likely to believe “a lot” that obesity is inherited (28.5%) compared to overweight (21.0%) and under/ normal weight respondents (16.2%). These findings suggest an area of focus for education and counseling. Our findings also indicate that a substantial proportion of adults, independent of their weight status, believe that levels of physical activity and exercise have no effect on cancer risk and that there is little that a person can do to decrease risk of cancer. Because accumulating evidence contradicts this pessimism, these misconceptions also should be the target of education.

Our use of data from HINTS 2007 is subject to the usual cautions about self-reported information. Our calculation of BMI was based on height and weight figures provided by respondents. Some of the subgroups of interest are rather small, rendering the resulting estimates potentially unstable. The HINTS 2007 sample is generally considered to be representative of the US adult population. We focused on adults aged 40 to 75 years because this is the age range in which cancer is common and prevention may be particularly valuable in terms of extension of quality life.

Our findings reinforce the notion that educational lifestyle interventions that may also reduce risk of cancer are particularly salient for obese adults. Patients who are advised by physicians to lose weight are more likely to attempt to do so.18 Active physician intervention, either in-person or remotely, has been shown to be effective.12,19 And while intervention sessions can be efficient, there is limited literature on physician compliance to physical activity counseling.20 The patient-physician interaction is an important and often missed opportunity to encourage patients to change their behavior.18 Physicians often do not provide weight reduction counseling to obese patients.21 We recognize physicians already do not have enough time to address delivery of services for recommended care; some studies estimate between 7 and 10 hours a day are needed.22,23 However, even brief counseling, delivered in the primary care setting and lasting three to 10 minutes, can be effective24 in improving management of multiple diseases. Physician follow-up with patients should be widely encouraged.20

Healthy lifestyle has been associated with reduced risk of certain cancers. We found that obese middle-aged adults were more likely than normal/underweight adults to perceive a high personal risk of cancer. These findings may provide an opportunity for focused counseling that targets both excess weight and cancer risk. To implement the USPSTF recommendation, both practicing clinicians and trainees need to learn how and when to counsel or refer overweight and obese patients.

Acknowledgments No funding supported this project. The content is solely the responsibility of the authors and does not necessarily represent the official views of the University of Missouri. We thank Robert Blake, M.D. from the University of Missouri for his helpful comments on an earlier version of this manuscript. We continue to be grateful to Susan Meadows and Susan Elliott for their excellent library support services at the University of Missouri in Columbia.

While the HINTS data do not directly address patient counseling, our results raise the potential for future research for systematic evaluation of weight management interventions, as is consistent with USPSTF priorities, that communicate cancer prevention benefits. The FRAMES mnemonic is recommended for physician intervention to assist patients with motivation to change: (1) giving Feedback based on a thorough assessment; (2) helping the patient take Responsibility for changing; (3) giving clear Advice on what behavior must change; (4) offering a Menu of options for making the change; (5) expressing Empathy for the ambivalence and difficulty in making changes; and (6) evoking Self-efficacy to foster commitment and confidence.20 Clinician comfort with delivering brief counseling might be improved by role playing exercises, including exercises with overweight and obese individuals who could give specific, informed feedback regarding the provider’s empathy and clarity. This practical approach recognizes both the time constraints facing primary care clinicians and their relative lack of training in obesity management.

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Service is not a chore, Service is a privilege. - Mother Teresa

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