Original Article doi: 10.1111/joim.12165
An emerging double burden of disease: the prevalence of individuals with cardiovascular disease and cancer C. Kreatsoulas1, S. S. Anand2 & S. V. Subramanian1 From the 1Department of Social and Behavioural Sciences, Harvard School of Public Health, Harvard University, Boston, MA, USA; and 2 Chanchlani Research Centre, McMaster University, Hamilton, ON, Canada
Abstract. Kreatsoulas C, Anand SS, Subramanian SV (Department of Social and Behavioural Sciences, Harvard School of Public Health, Harvard University, Boston, MA, USA; and Chanchlani Research Centre, McMaster University, Hamilton, ON, Canada). An emerging double burden of disease: the prevalence of individuals with cardiovascular disease and cancer. J Intern Med 2014; 275: 494–505. Objective. Cardiovascular disease (CVD) and cancer are the two leading causes of death in the United States; at the same time, the number of survivors is increasing as therapies continue to improve. The primary objective of this study is to determine the prevalence and characteristics of individuals affected by both CVD and cancer. Design and setting. We conducted a prevalence study using the 2009 and 2010 national Behavioural Risk Factor Surveillance System population survey. Data from a random sample of individuals (aged 25–99 years) from all states were collected. All participants provided information regarding their CVD and cancer status. Multivariable regression identified associations between participants’ characteristics and the prevalence of double disease burden.
Introduction Cancer and cardiovascular disease (CVD), which includes coronary artery disease (CAD), are the two leading causes of mortality in the Western world, accounting for half the total mortality across adults of all ages [1]. The incidence of both CVD and cancer rises with age; 77% of all cancers are diagnosed in those aged 55 years or older [2], and the risk of CVD increases after the age of 55 years amongst men and 65 years amongst women [3]. Concurrently, significant advances have improved the prognosis of patients with cancer, where the 5-year relative survival rate for all cancers is now
494
ª 2013 The Association for the Publication of the Journal of Internal Medicine
Results. Amongst 442 964 study participants, the overall prevalence rates were 11% for CVD and 15% for cancer; 3% of participants reported being survivors of both CVD and cancer. The prevalence of CVD+cancer increased twofold by 65 years of age (odds ratio [OR] 2.4, 95% confidence interval [CI] 2.3–2.5) and doubled again at ≥75 years (OR 4.9, 95% CI 4.6–5.1) and was higher amongst men (OR 1.6, 95% CI 1.6–1.7), multiracial individuals (OR 1.8, 95% CI 1.5–2.0) and those without a high school diploma (OR 1.3, 95% CI 1.2–1.4). Amongst individuals with CVD, 25% also reported having cancer, whilst 19% of all cancer survivors reported having CVD. Conclusions. The prevalence of the double burden of disease increased with age; this is particularly important as the ‘baby boomers’ reach this highrisk age group. Future studies should explore potential common upstream or downstream mechanisms of CVD and cancer as well as public health strategies to cope with the double burden of disease. Keywords: cancer, cardiovascular disease, multimorbidity, prevalence.
67% (up from 49% two decades ago) [2]. Similarly, age-adjusted CVD mortality has been declining for decades, with 44% of this improvement being attributed to risk factor modification and 47% to improvements in treatment [4]. Currently, there are over 12 million American adults living with a history of cancer [2] and 80 million living with CVD [5]. These numbers reveal the high prevalence rates of both diseases, whilst highlighting remarkable medical achievements. However, as therapies and survival improve, a large cohort of ‘baby boomers’ are reaching the age when these diseases typically manifest, and
C. Kreatsoulas et al.
from a broad health perspective, the proportion of the population at-risk is increasing. Because of the potential impact of the two most prevalent diseases emerging in parallel and interacting together, it is essential to consider how we collectively think about these two diseases. Further, few studies have explored the population of individuals with a double burden of these diseases. The Behavioural Risk Factor Surveillance System (BRFSS) is ideally suited to capture prevalence data as it is nationally represented, collected by the Centres for Disease Control and Prevention [6]. The objectives of the present study were to determine (i) the prevalence and proportion of individuals with CVD who have cancer, and those with cancer who have CVD, (ii) the effects of age, sex, race/ethnicity and education on the prevalence of the double burden of disease amongst single disease groups and (iii) the age-adjusted prevalence of the double burden of disease according to the American state/ territory of residence. Methods Data sources Data were obtained from the 2009 and 2010 BRFSS surveys, an annual cross-sectional nationally representative telephone survey of over 400 000 noninstitutionalized adults aged 18 years and above. Participants are interviewed in a multistaged cluster design using random-digit dialling within blocks of phone numbers to determine the probability sample of households with telephones in each state. In each household, one adult is randomly selected and interviewed, with representation from all 50 American states, including District of Columbia, and island territories [6]. The BRFSS survey is designed in two parts: first, all participants are asked a core group of standard questions regarding health perceptions, disease conditions, risk factors, behaviours and demographic characteristics. The second component consists of additional modules that may change yearly. We selected the years 2009 and 2010 because data on both cardiovascular health and cancer survivorship were captured amongst the same individuals [6]. The BRFSS is a publically available de-identified data set; therefore, ethical approval was not required by the Harvard Human Research Ethics Board.
Cardiovascular disease and cancer prevalence
Study population Questions regarding CVD and CAD were extracted from the core survey (n = 883 681), and only participants who did not provide answers to these specific questions were excluded (n = 4). The cancer variable was captured from a secondary module to which 472 733 individuals responded. We excluded 33 814 individuals who were younger than 25 years of age because the risks of both CVD and cancer are exceedingly low in this age group [1]. Sex and age data were available for all participants, and we excluded missing data related to race (n = 11 154) and education (n = 3128). After excluding missing values and including all those who provided information for both CVD and cancer, our total study population consisted of 442 964 participants (Fig. 1). Two additional dependent variables were designed to capture the prevalence of survivors with a double burden of disease: CAD+cancer and CVD+cancer. For the main independent variables, age was categorized into six groups: 25 to
An emerging double burden of disease: the prevalence of individuals with cardiovascular disease and cancer C. Kreatsoulas1, S. S. Anand2 & S. V. Subramanian1 From the 1Department of Social and Behavioural Sciences, Harvard School of Public Health, Harvard University, Boston, MA, USA; and 2 Chanchlani Research Centre, McMaster University, Hamilton, ON, Canada
Abstract. Kreatsoulas C, Anand SS, Subramanian SV (Department of Social and Behavioural Sciences, Harvard School of Public Health, Harvard University, Boston, MA, USA; and Chanchlani Research Centre, McMaster University, Hamilton, ON, Canada). An emerging double burden of disease: the prevalence of individuals with cardiovascular disease and cancer. J Intern Med 2014; 275: 494–505. Objective. Cardiovascular disease (CVD) and cancer are the two leading causes of death in the United States; at the same time, the number of survivors is increasing as therapies continue to improve. The primary objective of this study is to determine the prevalence and characteristics of individuals affected by both CVD and cancer. Design and setting. We conducted a prevalence study using the 2009 and 2010 national Behavioural Risk Factor Surveillance System population survey. Data from a random sample of individuals (aged 25–99 years) from all states were collected. All participants provided information regarding their CVD and cancer status. Multivariable regression identified associations between participants’ characteristics and the prevalence of double disease burden.
Introduction Cancer and cardiovascular disease (CVD), which includes coronary artery disease (CAD), are the two leading causes of mortality in the Western world, accounting for half the total mortality across adults of all ages [1]. The incidence of both CVD and cancer rises with age; 77% of all cancers are diagnosed in those aged 55 years or older [2], and the risk of CVD increases after the age of 55 years amongst men and 65 years amongst women [3]. Concurrently, significant advances have improved the prognosis of patients with cancer, where the 5-year relative survival rate for all cancers is now
494
ª 2013 The Association for the Publication of the Journal of Internal Medicine
Results. Amongst 442 964 study participants, the overall prevalence rates were 11% for CVD and 15% for cancer; 3% of participants reported being survivors of both CVD and cancer. The prevalence of CVD+cancer increased twofold by 65 years of age (odds ratio [OR] 2.4, 95% confidence interval [CI] 2.3–2.5) and doubled again at ≥75 years (OR 4.9, 95% CI 4.6–5.1) and was higher amongst men (OR 1.6, 95% CI 1.6–1.7), multiracial individuals (OR 1.8, 95% CI 1.5–2.0) and those without a high school diploma (OR 1.3, 95% CI 1.2–1.4). Amongst individuals with CVD, 25% also reported having cancer, whilst 19% of all cancer survivors reported having CVD. Conclusions. The prevalence of the double burden of disease increased with age; this is particularly important as the ‘baby boomers’ reach this highrisk age group. Future studies should explore potential common upstream or downstream mechanisms of CVD and cancer as well as public health strategies to cope with the double burden of disease. Keywords: cancer, cardiovascular disease, multimorbidity, prevalence.
67% (up from 49% two decades ago) [2]. Similarly, age-adjusted CVD mortality has been declining for decades, with 44% of this improvement being attributed to risk factor modification and 47% to improvements in treatment [4]. Currently, there are over 12 million American adults living with a history of cancer [2] and 80 million living with CVD [5]. These numbers reveal the high prevalence rates of both diseases, whilst highlighting remarkable medical achievements. However, as therapies and survival improve, a large cohort of ‘baby boomers’ are reaching the age when these diseases typically manifest, and
C. Kreatsoulas et al.
from a broad health perspective, the proportion of the population at-risk is increasing. Because of the potential impact of the two most prevalent diseases emerging in parallel and interacting together, it is essential to consider how we collectively think about these two diseases. Further, few studies have explored the population of individuals with a double burden of these diseases. The Behavioural Risk Factor Surveillance System (BRFSS) is ideally suited to capture prevalence data as it is nationally represented, collected by the Centres for Disease Control and Prevention [6]. The objectives of the present study were to determine (i) the prevalence and proportion of individuals with CVD who have cancer, and those with cancer who have CVD, (ii) the effects of age, sex, race/ethnicity and education on the prevalence of the double burden of disease amongst single disease groups and (iii) the age-adjusted prevalence of the double burden of disease according to the American state/ territory of residence. Methods Data sources Data were obtained from the 2009 and 2010 BRFSS surveys, an annual cross-sectional nationally representative telephone survey of over 400 000 noninstitutionalized adults aged 18 years and above. Participants are interviewed in a multistaged cluster design using random-digit dialling within blocks of phone numbers to determine the probability sample of households with telephones in each state. In each household, one adult is randomly selected and interviewed, with representation from all 50 American states, including District of Columbia, and island territories [6]. The BRFSS survey is designed in two parts: first, all participants are asked a core group of standard questions regarding health perceptions, disease conditions, risk factors, behaviours and demographic characteristics. The second component consists of additional modules that may change yearly. We selected the years 2009 and 2010 because data on both cardiovascular health and cancer survivorship were captured amongst the same individuals [6]. The BRFSS is a publically available de-identified data set; therefore, ethical approval was not required by the Harvard Human Research Ethics Board.
Cardiovascular disease and cancer prevalence
Study population Questions regarding CVD and CAD were extracted from the core survey (n = 883 681), and only participants who did not provide answers to these specific questions were excluded (n = 4). The cancer variable was captured from a secondary module to which 472 733 individuals responded. We excluded 33 814 individuals who were younger than 25 years of age because the risks of both CVD and cancer are exceedingly low in this age group [1]. Sex and age data were available for all participants, and we excluded missing data related to race (n = 11 154) and education (n = 3128). After excluding missing values and including all those who provided information for both CVD and cancer, our total study population consisted of 442 964 participants (Fig. 1). Two additional dependent variables were designed to capture the prevalence of survivors with a double burden of disease: CAD+cancer and CVD+cancer. For the main independent variables, age was categorized into six groups: 25 to
