1. Peak oxygen uptake and prevalence of cardiovascular disease risk factors in breast cancer survivors Lahart1, I.M., Metsios1, G.S., Nevill1, A.M., Kitas1,2, G. and Carmichael2, A.R. 1. University of Wolverhampton 2. Russells Hall Hospital, Dudley
Summary
Low cardiorespiratory fitness (CRF) is associated with increased breast cancer and cardiovascular disease (CVD) mortality risk. In our sample of breast cancer survivors we report low CRF and relatively high prevalence of CVD risk factors, highlighting the need for effective interventions aimed at reducing modifiable CVD risk factors in this population
Introduction
CRF is associated with both increased breast cancer and CVD mortality risk, independent of adiposity. Women diagnosed with breast cancer experience an excess of CVD mortality. Breast cancer survivors with low CRF and risk factors for CVD may be at a higher risk of mortality. Therefore, the purpose of the current study was to examine the CRF levels and prevalence of CVD risk factors in a sample of breast cancer patients within one year of completing post-adjuvant therapy.
Table 1. Definitions of CVD Risk Factor Strataa
Risk Model 1*
Risk Model 2
(model 1 +
PA & BMI)
Systolic and Diastolic Blood Pressure (mmHg)
Total Cholesterol (mmol∙L-1)
Diabetes
Tobacco Smoking**
Sufficient PA†
BMI (kg/m2)
All optimal
<120 and <80 and
<180 and
No and
Yes and
18.5–
24.9
≥1 Not optimal
or or
and
Yes -
≥1 Elevated
or or
and ≥
1 Major
≥160 or ≥100 or treated or
≥240 or treated or
Yes or
No or
≥30.0
≥2 major
≥160 or ≥100 or treated and/or
≥240 or treated and/or
Yes and/or
No and/or
Methods
With local NHS ethics committee approval, 32 breast cancer patients (age=52±10 years; height=162±5.4 cm; mass=70.6±10.3 kg; BMI=27.2±4.4 kg∙m2; chemotherapy received=16/32, 50%) underwent an incremental exercise tolerance test to symptom limitation to assess CRF (peak oxygen uptake, VO2peak). Pre-test patient’s height and mass measurements were taken and physical activity (PA) was assessed via International PA Questionnaire (IPAQ). We assessed via questionnaire prevalence of pre-existing co-morbidities such as CVD, hypertension, hyperlipidaemia, diabetes, chronic kidney disease (CKD) and rheumatoid arthritis (RA). In addition, patients without a diagnosed co-morbidity were screened for major CVD risk factors (see Table 2). We stratified CVD risk based on Wilkins et al., (2012) model (model 1), and an additional model (2) with insufficient PA and overweight/obesity included (see Table 1).
a Risk factors are additive. Table must be interpreted left to right
* Risk Model 1 adopted from Wilkins et al. (2012)
** All current smokers and those who quit smoking less than 1 year before the assessment were considered smokers
† Defined as not meeting recommended UK PA guidelines according to IPAQ categorical score
Results
Mean VO2peak (25.3±4.7 ml∙kg-1∙min-1) of the breast cancer patients was classified as “poor” compared age and gender group matched normative values. Eight breast cancer survivors had pre-existing co-morbidities. The prevalence of pre-existing co-morbidities and major CVD risk factors for the remaining participants who were not diagnosed with a pre-existing co-morbidity are provided in table 2. According, to risk stratification model 1, only one (4%) participant had all optimal levels of included risk factors, however, 12 (48%) and 18 (72%) participants had at least one major risk factor based on model 1 and 2, respectively (Table 3).
Table 2. Prevalence of CVD risk factors in breast cancer survivors (n=25)
Table 3. Distribution of CVD Risk Factor Strataa
Co-Morbidity
Number of participants (%)
History of heart disease
2 (6%)
Diagnosed with hypertension
4 (13%)
Diagnosed with hyperlipidaemia
3 (9%)
Diagnosis of diabetes and >40 years old
1 (3%)
Diagnosed with chronic kidney disease
Diagnosed with rheumatoid arthritis
CVD risk factor
Age ≥85 years
0 (0%)
Overweight/obese (BMI ≥25.0 kg/m2)
14 (44%)
Ever smoker
12 (38%)
Consumption of ≥1 alcoholic drink/day
9 (28%)
Insufficient PA
8 (25%)
Systolic Blood Pressure (≥140 mmHg)
Diastolic Blood Pressure (≥90 mmHg)
Total cholesterol (TC ≥6.2 mmol∙L-1)
5 (16%)
Non-High-density lipoprotein-cholesterol (non-HDL-C ≥3.4 mmol∙L-1)
13 (41%)
Triglycerides (TG ≥2.3 mmol∙L-1)
10 (31%)
HDL-C (≤1.0 mmol∙L-1)
Fasting glucose (≥7 mmol∙L-1)
Age Groups of Participants, y
Prevalence of Aggregate Risk Factors, n (%)
Total
(n=25)
35-44
(n=7)
45-54
(n=11)
55-64
(n=5)
65-74
(n=2)
Model 1
Model 2
All optimal
1 (4)
0 (0)
1 (14)
≥1 Not optimal
8 (32)
3 (12)
2 (29)
4 (36)
1 (20)
1 (50)
≥1 Elevated
4 (16)
2 (18)
1 Major
12 (48)
11 (44)
3 (43)
5 (45)
7 (64)
4 (80)
≥2 major
7 (28)
3 (60)
a See Table 1 for risk factor category definitions.
Conclusions
Post-adjuvant therapy breast cancer patients had on average poor CRF compared to age and gender matched normative values, and reported a relatively high prevalence of CVD risk factors. Therefore, a relatively large number of our sample were exposed to an increased risk of CVD and breast cancer-related mortality. Our data suggest that this patient group would benefit from CVD and breast cancer mortality risk lowering interventions.
References
Miller M et al (2011) Circulation 123:
Reiner Z et al (2011) Eur Heart J 32:
Mendis S et al (2011) World Health Organization, Geneva.
Wilkins JT et al (2012) JAMA 308: