Brief 4: Physical Activity: Cancer Risk Perceptions and Group Differences in Behavior

Many Americans Believe Physical Activity Reduces Cancer Risk, But a Majority Find Physical Activity Recommendations Confusing

The majority of Americans believe that physical activity plays a role in preventing cancer. However, when asked which cancers physical activity helps to prevent, 68% of respondents to the Health Information National Trends Survey (HINTS 2003) said they did not know, while fewer than 5% accurately identified colorectal cancer. Nearly 14% inaccurately said exercise helps to prevent all cancers, and 8% inaccurately said lung cancer.

Promoting and enabling regular physical activity are important disease prevention strategies in general, as exercise is beneficial for overall health, and especially in preventing cardiovascular disease and diabetes. HINTS reveals another important intervention strategy for cancer prevention efforts: targeting messages about exercise to those at risk for colorectal cancer, the second leading cause of cancer mortality in the U.S.

Increasing physical activity is associated with a 40% reduction of risk of colon cancer. Encouragingly, 64% of Americans report that they pay attention to physical activity messages they hear in the media. A large majority of Americans (75%) say there are so many physical activity recommendations that it is hard to know which ones to follow. When thinking about the last time they heard a recommendation about exercise, 42% said they did not change their behavior, 18% did change their behavior, and 39% waited to get more information. When asked if, in the past year, they had seen, heard, or read anything about physical activity and cancer, 68% of HINTS respondents said they had not; 31% had (HINTS 2005).

In this HINTS Brief, we compare physically active and inactive people, and explore the sociodemographic and information-seeking characteristics they possess.

When given the names of screening tests to detect certain cancers (e.g., mammogram, fecal occult blood test), the majority of Americans say they have heard of the tests, and many Americans say they have been screened for cancer. However, most people aren’t sure at what age they should begin screening or how often they should be screened. In this HINTS Brief, we explore people’s knowledge about screening tests for breast, cervical, and colorectal cancers.

Which types of cancer does physical activity help to prevent?

d

What did you do the last time you heard or read a new physical activity recommendation?

d

Inactive Adults

Identifying subgroups for intervention

In a HINTS study published in 2006, investigators conducted an analysis to obtain insight into the sociodemographic and information-seeking characteristics of active and inactive adults, by identifying subgroups of inactive adults with distinct characteristics.

Compared to respondents who reported being physically active, inactive respondents were

• older
• more likely to be women
• not married
• non-White
• less educated
• less likely to have a higher income
• less likely to live in metropolitan areas
• in poorer general health
• less likely to have health insurance
• more overweight
• less likely to believe exercise lowers cancer risk
• less likely to eat five or more servings of vegetables and fruit per day
• more likely to have smoked 100 or more cigarettes in their lifetime

In terms of media exposure and information seeking, the inactive adults were less likely to have used the Internet, and less likely to pay attention to health messages in the media. They also watched more hours of television per day and read newspapers and magazines less frequently than the physically active respondents to the survey.

A highly inactive group of adults described in the study as "limited media users" did not read the newspaper or pay attention to other media, was less educated, had low income, was more likely to be Hispanic/Latino, and did not have a regular healthcare provider or health insurance. Although this inactive group pays less attention to media, they can be reached by telephone, which may be an important intervention channel for this group.

Physical Activity Trends: Differences by Age, Race, and Gender

Age
Physical activity levels decline with age. Older adults are less likely to be as physically active as children or young adults. Among youth, physical activity is lower among females, especially African American females.

Race/Ethnicity
African Americans and Hispanics are more likely than Whites to report no leisure-time physical activity. When asked whether they pay attention to or ignore physical activity recommendations, Hispanics are more likely than Whites and African Americans to say they pay attention to recommendations.Whites are more likely to say they ignore recommendations. Hispanics also are more likely to say they have changed their behavior based on physical activity messages in the media. Whites are more likely to say recommendations do not influence their behavior.

Gender
Women are more likely than men to report no leisure-time physical activity. However, they are more likely than men to report using the Internet to look for information about exercise, and they are more likely than men to say they pay attention to physical activity recommendations they read or hear about.

How Can This Inform Your Work?

Americans seem to be getting the general message that exercise is beneficial for health, but acting on that knowledge remains a challenge. Public understanding of the role of physical activity in cancer risk reduction is evident; however, people are unsure about which cancers can be prevented with exercise. Key implications from HINTS suggest that

• All adults, especially those at risk for developing colorectal cancer (because of family history or other relevant risk factors), could benefit from understanding physical activity recommendations and becoming regular exercisers.
• Hispanics, more than any other racial or ethnic group, are paying attention to and acting on physical activity recommendations they read or hear about. Their readiness to change could enhance targeted interventions.
• Women are looking for information about exercise online, and are likely to pay attention to messages aimed at increasing physical activity.
• Interventions aimed at substituting television watching with more active behaviors may be effective for the most physically inactive adults.
• Some highly inactive groups have limited exposure to media channels and pay less attention to health messages through the media. They may require intensive person-to-person communication efforts aimed at informing them about the health benefits of increasing physical activity.

References Used in This HINTS Brief

Atienza AA, Yaroch AL, Masse LC, Moser RP, Hesse BW, King AC. Identifying sedentary subgroups: The National Cancer Institute's Health Information National Trends Survey. Am J Prev Med. 2006 Nov;31(5):383-90.

HHS/USDA Dietary Guidelines for Americans 2005, http://www.healthierus.gov/dietaryguidelines

Healthy People 2010 Physical Activity and Fitness, http://www.healthypeople.gov/Document/HTML/Volume2/22Physical.htm#_Toc490380795

NCI’s Cancer Trends Progress Report 2005, http://progressreport.cancer.gov

For More Information on Cancer

• Call the NCI Cancer Information Service at 1-800-4-CANCER (1-800-422-6237)



• Visit http://cancer.gov



• Order NCI publications at http://www.cancer.gov/publications

August 2006