Despite proven benefits of physical activity, adults in the United States may not be meeting activity guidelines for aerobic and strength exercise. There is an association between physical activity and reduced cancer risk, and reduced risk of reoccurrence among cancer survivors. This study aims to describe the odds of meeting aerobic, strength, and combined levels of physical activity based on the recommendations of the Physical Activity Guidelines for Americans among adults in the U.S., making comparisons by cancer status and demographics.
Logistic regression of cross-sectional data from Cycles 4 and 5 of the Health Information National Trends Survey (HINTS) was conducted. The independent variables were cancer type, age, race/ethnicity, education level, income, and data year; dependent variables included meeting aerobic, strength, and combined aerobic and strength physical activity guidelines. Analyses were stratified by gender.
Among women, 25.6% who survived all other cancers met aerobic physical activity guidelines of at least 150 minutes of medium intensity or higher levels of physical activity weekly, while 32.4% of breast cancer survivors and 35.6% of those with no cancer history met aerobic guidelines. Female survivors of cancers other than breast cancer compared to those with no cancer history had significantly lower odds (OR = 0.6, p = 0.004) of meeting aerobic physical activity guidelines. Women and men of all age groups compared to those ages 18-34 had lower odds (all p < 0.05) of meeting both aerobic and strength physical activity guidelines. Non-Hispanic Black men compared to white men (OR = 2.5, p < 0.001), high-income women ($75,000 or more per year) compared to those making under $20,000 (OR = 1.5, p = 0.030), and women of all education levels compared to women with less than high school education had higher odds of meeting both aerobic and strength guidelines (all p < 0.05).
Female cancer survivors and older adults have lower odds of meeting physical activity guidelines; exercise interventions targeting these groups may be necessary to address this disparity.
Aerobic exercise, Strength training, Cross-sectional survey, Breast cancer, Prostate cancer
Cancer is the second leading cause of death in the United States, accounting for 21.8% of deaths in 2015-2016 [1]. There appears to be a relationship between physical activity and risk of cancer incidence; high versus low levels of physical activity is associated with lower risk for 13 cancer types [2] and as a result, there is a high level of interest in exploring the linkage further. The Physical Activity Guidelines for Americans published by the U.S. Department of Health and Human Services recommend 150 minutes of moderate intensity or 75 minutes of vigorous intensity aerobic activity weekly, in addition to muscle strengthening activities on at least 2 days per week for all adults [3]. For adults with cancer, current research-based guidelines suggest that survivors seek to achieve this level of activity as soon as possible after diagnosis and treatment [4].
Further, while the relationship between physical activity and cancer incidence is associational, there is also evidence that physical activity is associated with lower risk of adverse side effects of cancer and medical treatments, and lower mortality after diagnosis [5]. For instance, cancer patients undergoing treatment may suffer from the effects of cachexia, or muscle wasting, which is exacerbated by some kinds of cancer therapy [6]; chemotherapy in particular may cause side effects including fatigue, nausea, hair loss, weight changes, mood changes, and other effects that negatively impact quality of life [7]. Among cancer patients undergoing treatment, aerobic and strength activity interventions have been shown to increase muscle mass, muscle strength, physical functioning, and balance and reduce fatigue [8,9]. Physical activity can also improve multiple psychological and psychosocial outcomes, outcomes of particular focus for individuals diagnosed with cancer. Specifically, exercise interventions have led to improvements in depression, anxiety, body image, well-being, mood, and health-related quality of life in cancer patients [10,11].
Yet those with cancer and cancer survivors note a number of barriers impact their levels of physical activity. Barriers to exercise reported by those with cancer include pain, fatigue, and insomnia during cancer treatment, while cancer survivors note other barriers including being too busy, having little willpower, weather, responsibilities at home, and not enjoying exercise after treatment [12]. As it is essential for those diagnosed with and treated for cancer to overcome these barriers to improve and maintain health status, prevent reoccurrence, and potentially reduce the incidence of other chronic diseases through physical activity, it is important to improve our understanding of the factors that may impact adults' physical activity levels.
Prior work by Ottenbacher, et al. explored the likelihood of meeting aerobic and strength activity guidelines comparing cancer survivors to those with no history of cancer using the National Cancer Institute's Health Information National Trends Survey (HINTS) data for years 2011 & 2012 [13]. Since then, additional data have been collected, introducing the opportunity to explore whether these findings about physical activity among cancer survivors have persisted with more data. In addition, there are demographic factors that may influence physical activity previously unreported using HINTS data. This study thus aims to compare the odds of cancer survivors in the U.S. meeting recommendations from the Physical Activity Guidelines for Americans for aerobic and strength physical activity to the odds of adults with no history of cancer meeting these guidelines, controlling for age, race/ethnicity, income, and education.
The Health Information National Trends Survey (HINTS), sponsored by the National Cancer Institute (NCI), is fielded annually to a representative sample of U.S. adults over 18 years of age. HINTS collects data about how respondents seek and use information about cancer, as well as about communication practices, cancer risk perception, cancer prevention behavior, and demographics [14]. This study uses data from HINTS 4, cycles 1 (2011), 2 (2012), and 3 (2013), and HINTS 5, cycles 1 (2017) and 2 (2018). HINTS had a response rate of 37% in HINTS 4 Cycle 1, 40% in Cycle 2, 35% in Cycle 3, 32% in HINTS 5 Cycle 1 and 33% in HINTS 5 Cycle 2 [1]. Non-response was systematically more likely for respondents who were male, minority, younger, less educated, or Hispanic. HINTS is published with survey weights to allow the results to be more generalizable to the population.
In comparison to the original paper, three additional years of data and other covariates (i.e., income and data year) were added. In addition, all the independent variables are presented rather than used solely for adjustment. By incorporating an additional year of data, the sample size is increased (2011-2012: 7,310, 2011-2018: 16,773), allowing for the identification of patterns that were difficult previously to identify based on the smaller sample size in prior work. Following Ottenbacher's approach, we divided our sample into males and females, accounting for variation in physical activity and cancer type by gender.
HINTS includes two questions inquiring about aerobic physical activity: "In a typical week, how many days do you do any physical activity or exercise of at least moderate intensity, such as brisk walking, bicycling at a regular pace, swimming at a regular pace, and heavy gardening?" and "On the days that you do any physical activity or exercise of at least moderate intensity, how long are you typically doing these activities?" [16] HINTS also includes one question about muscle-strengthening activities: "In a typical week, outside of your job or work around the house, how many days do you do leisure-time physical activities specifically designed to strengthen your muscles such as lifting weights or circuit training (do not include cardio exercise such as walking, biking, or swimming)?" Responses to these three questions were transformed into binary variables indicating whether guidelines were met or not met; these became the dependent variables in our analysis. Respondents met aerobic guidelines if total minutes of exercise of at least moderate intensity totaled 150 minutes per week or more. Strength guidelines were met if respondents reported 2 days or more of muscle-strengthening activities.
Two questions were asked to determine cancer history: "Have you ever been diagnosed as having cancer?" and "What type of cancer did you have?" Respondents were categorized based on cancer history. A categorical variable was created using the two most common cancer types, breast and prostate, to compare these cancers with all other cancers and people with no cancer history. Respondents in the "breast or prostate cancer category" reported a history of those cancer types; those in the "all other survivors" category had a history of any cancer other than breast, prostate, or non-melanoma skin cancer; and those in the "no history of cancer" category reported they had never been diagnosed with cancer, consistent with the approach followed by Ottenbacher, et al. [13] These cancer type categories were primary independent variables of interest in this analysis; other independent variables included income level, education level, age, race/ethnicity, and data year.
This analysis was loosely patterned on the analytic approach outlined previously by Ottenbacher, et al. [13] Notably, missing values were not imputed to take a conservative approach with assumptions in the data. Additionally, income was included as a covariate does not present in the original analysis to control for socioeconomic differences, and data year was added to examine differences over time. Multivariate logistic regression was used to assess the weighted association between the dependent variables, meeting aerobic, strength, and combined physical activity guidelines, and the independent variables, cancer status, age, race/ethnicity, income, education, and data year. Weighted percentages and confidence intervals were calculated for demographic data. All analyses were completed using Stata version 14 (2015, Stata Corp LP, College Station, TX).
The weighted demographic estimates for the pooled data years is shown in Table 1. Gender, race/ethnicity, age, education, data year, time since diagnosis, and type of cancer are presented. Of those with a history of cancer, 22.4% were survivors of breast cancer, 15.4% were prostate cancer survivors, and 62.3% were survivors of any other type of cancer.
Table 1: Demographics by cancer status. View Table 1
Only 25.6% of women who survived all other cancers met aerobic guidelines, while 32.4% of breast cancer survivors and 35.6% of those with no cancer history met guidelines (Figure 1). Women who survived cancers other than breast had lower odds of meeting aerobic guidelines compared to women with no history of cancer (OR = 0.6, p = 0.004). Women of all age groups had significantly lower odds of meeting aerobic guidelines compared to women aged 18-34. Non-Hispanic Black women and women who were part of the 2018 cohort had significantly lower odds of meeting aerobic guidelines. Women with any education level of high school graduate or more had higher odds of meeting aerobic guidelines compared to women with less than a high school education.
Figure 1: Percent of women meeting physical activity guidelines. View Figure 1
Of all other female cancer survivors, 24.2% met strength guidelines, 28.2% of breast cancer survivors met guidelines, and 30.8% of those with no cancer history met strength guidelines (Figure 1). There were no differences in meeting strength guidelines by cancer status among women. Women in the 50-64, 65-74, and 75+ year age brackets had lower odds of meeting the strength guidelines compared to women aged 18-34. Women in the 2012, 2013, 2017, and 2018 cohorts and women in the highest income bracket - more than $75,000 per year - had higher odds of meeting the strength guidelines.
Women with all other cancers were least likely to meet both guidelines (14.1%), followed by breast cancer survivors (17.2%) and those with no cancer history (19.7%) (Figure 1). There were no significant differences among women by cancer status. There were lower odds of women in all age categories meeting both guidelines compared to those ages 18-34 (all p < 0.05). There were higher odds of women in all education categories meeting both guidelines compared to women with less than a high school education (all p < 0.05). The odds of meeting both guidelines were significantly higher for women with an income > $75,000 and women in the 2017 cohort (Table 2).
Table 2: Odds of meeting physical activity guidelines for women. View Table 2
The percentage of men meeting aerobic activity guidelines was highest among those with no history of cancer (47.5%), then all other cancer survivors (40.4%), and lastly prostate cancer survivors (40.2%) (Figure 2). There were no significant differences in odds of meeting aerobic activity guidelines by cancer status for men (Table 3). Men in age groups 35-49, 50-64, and 75 and older had lower odds of meeting aerobic guidelines compared to men 18-34 (all p < 0.05). Non-Hispanic Black men and men with some college education had higher odds of meeting aerobic guidelines. Those in the 2012 and 2013 cohorts had higher odds of meeting aerobic guidelines than those in the 2011 cohort.
Figure 2: Percent of men meeting physical activity guidelines. View Figure 2
Table 3: Odds of meeting physical activity guidelines for men. View Table 3
The percentage of men with prostate cancer meeting strength guidelines was 32.3%, the percentage of all other survivors was 37.1%, and the percentage with no cancer history was 39.5% (Figure 2). There were no significant differences in the odds of men meeting strength guidelines by cancer status. All age groups had lower odds of meeting the strength guidelines compared to men ages 18-34 (all p < 0.05). Non-Hispanic Black men, college graduates, and men in the 2017 cohort were more likely to meet the strength guidelines.
Men with prostate cancer were least likely to meet both guidelines (15.7%), 23.8% of all other cancer survivors met guidelines, and 27.9% of men with no cancer history met guidelines (Figure 2). The odds of meeting both guidelines were not significantly different by cancer history for men after adjusting for demographics. There were lower odds of men in all age groups meeting the guidelines compared to men ages 18-34 (all p < 0.05). Non-Hispanic Black men and men in the 2017 cohort had higher odds of meeting both guidelines.
After adjusting for demographic factors, women who survived cancers other than breast cancer were less likely to meet guidelines for aerobic activity compared to women with no history of cancer. As breast cancer is often caught earlier with routine screening, this earlier detection suggests there may be less morbidity among women who had breast cancer compared to other cancers [17]. Earlier diagnosis may make it easier for these women to exercise, however, it was not possible to assess stage of cancer diagnosis and level of treatment using these data. Further, the documented preventive effect of exercise on breast cancer reoccurrence may encourage physical activity among breast cancer survivors [18]. A prior meta-analysis reported that 83% of physical activity interventions included breast cancer survivors [19], but physical activity interventions targeting survivors of other cancers may be needed to close this gap. Interestingly, women with a history of cancer other than breast did not have significantly lower odds of meeting strength guidelines when adjusting for demographic factors. While there is evidence that many physical activity interventions for cancer survivors focus on strength activities to prevent or treat muscle and strength loss [9,19], future research could assess whether this trend continues among cancer survivors.
There was an income effect on meeting strength and both guidelines for women, with high-income women (> $75,000) having higher odds of meeting guidelines compared to women in the lowest income category; notably, for men, there was no income effect. These results are consistent with the results of prior research that has shown that individuals with higher incomes may be more likely to live in environments conducive to physical activity [20]. There was another effect of socioeconomic status: women with higher education levels had higher odds of meeting aerobic and both exercise guidelines. The results for men were less significant; only those with some college education had higher odds of meeting aerobic guidelines, and those with college degrees had higher odds of meeting strength guidelines. These relationships did not persist for meeting both guidelines. While the relationship between education level and physical activity has been previously documented [21], studies of physical activity split by both gender and physical activity type have been rare. In this study, women's odds of exercise were more strongly impacted by socioeconomic status variables than men; our findings thus invite future research about the relationship between socioeconomic status and physical activity among women.
There were significant effects of race/ethnicity on physical activity for both genders. Non-Hispanic Black women performed significantly less aerobic activity than non-Hispanic White women. This disparity for Black women has been previously documented [22], with additional studies showing that Black women may be more successful at improving physical activity levels when programs are tailored to their preferences [23]. Environmental factors may contribute