Original article
Leisure-time physical activity and cardiovascular disease mortality: the Brisighella Heart Study Arrigo F.G. Cicero, Sergio D’Addato, Francesca Santi, Alienor Ferroni, Claudio Borghi, on behalf of the Brisighella Heart Study Objective The aim of this study is to describe the relationship between self-rated physical activity during leisure time and cardiovascular disease mortality in 2936 individuals of the cohort of the Brisighella Heart Study, a prospective, population-based, longitudinal, epidemiological survey. Methods Long-term (1988–2000) prognostic significance of physical activity was determined after adjustments for age, sex, smoking habits, low-density lipoproteincholesterol and history of type 2 diabetes. Results At baseline, 377 (25.3%) male and 496 (34.3%) female participants reported scarce-null physical activity, whereas 1112 (74.7%) men and 951 (65.7%) women reported medium-intense physical activity. In the entire population, cardiovascular mortality was three times higher in participants with sedentary physical activity than in those with medium-intense physical activity (P U 0.0001). These results have been confirmed in both men (P U 0.0001) and women (P U 0.0028). A categorical distribution of the
Introduction Physical inactivity is an independent cardiovascular risk factor for both cardiovascular disease (CVD) and (probably) total mortality in both industrialized1 and developing countries.2 Its negative effects on CVD risk are additive to that of the other well-known conventional and nonconventional CVD risk factors such as hypertension,3 atherogenic dyslipidemias,4 systemic low-grade inflammation5 and hemostatic disorders.6 Sedentary behavior is very common in the general population and it is associated with detrimental health outcomes.7 In particular, sedentary behavior is associated with an increased peripheral vascular tone and has a negative impact on vascular remodeling in both large and smaller arteries that could significantly contribute to the increased risk of CVD in these patients.8,9 Physical inactivity is, however, a potentially ‘reversible’ CVD risk factor with a good cost–benefit ratio, at least in the great majority of individuals, not needing large investments in terms of medical and human resources.10 A meta-analysis, which incorporated 459 833 participants free from CVD at baseline with 19 249 cases at follow-up showed a pooled hazard ratio of 0.69, [95% confidence interval (CI) ¼ 0.61–0.77, P < 0.001], 1558-2027 ß 2012 Italian Federation of Cardiology
population according to age showed a higher risk of cardiovascular death associated with sedentary physical activity only in the younger male particupants (P U 0.0032). Conclusion On the basis of our data, physical activity is inversely related to cardiovascular mortality in a sample of the rural Mediterranean population with a highest risk in inactive men aged less than 65 years. J Cardiovasc Med 2012, 13:559–564 Keywords: cardiovascular disease, epidemiology, general population, physical activity Department of Internal Medicine, Aging and Kidney Diseases, University of Bologna, Bologna, Italy Correspondence to Arrigo F.G. Cicero, MD, PhD, Internal Medicine, Aging and Kidney diseases Department, Sant’Orsola-Malpighi University Hospital, Poliambulatorio Pad. 2 - Via Albertoni, 15, 40138 Bologna, Italy Tel: +39 051626224; fax: +39 051390646; e-mail:
[email protected] Received 15 September 2011 Revised 1 January 2012 Accepted 13 January 2012
and 0.68 (CI ¼ 0.59–0.78, P < 0.001) for CVD and all-cause mortality, respectively, in the highest vs. the lowest walking category. In addition, a dose–response relationship was observed across the highest, intermediate, and lowest walking categories in relation to the outcome measures.11,12 This has been confirmed in high-risk patients, such as diabetic patients,13 whereas measurable cardiovascular benefits have been observed in sedentary individuals who adopt a more physically active lifestyle over time.14 In addition to its favorable effects on the rate of cardiovascular events, physical activity per se is a powerful tool for the prevention of type 2 diabetes15,16 and improves the therapeutic response to antihypertensive drugs.17 More recently, increasing evidence has supported the hypothesis that physical activity might contribute to prevent the development of vascular dementia, probably because of its positive effects on several risk factors for CVD.18 The aim of the present study is to describe the relationship between self-rated physical activity during leisure time and mortality for CVD in the historical cohort of the Brisighella Heart Study (BHS), characterized by a DOI:10.2459/JCM.0b013e3283516798
Copyright © Italian Federation of Cardiology. Unauthorized reproduction of this article is prohibited.
560 Journal of Cardiovascular Medicine 2012, Vol 13 No 9
specific genetic background19 and a relatively high level of conventional cardiovascular risk factors.20
Materials and methods The BHS is a prospective, population-based longitudinal epidemiological investigation started in 1972 and involving randomly selected participants, aged 14–84 years, free of CVD at enrolment, all resident in the rural town of Brisighella.21 The area of Brisighella was chosen because of the homogeneity of lifestyle among its residents, with a very low rate of migrations from other countries. Individuals were clinically evaluated at baseline and every 4 years thereafter by extensively assessing both clinical and laboratory profile according to a standardized protocol that has been described elsewhere in more detail.22 The information about morbidity and mortality of the population was progressively collected and adjudicated by an independent end-point committee according to the available clinical documentation and public records. In 1984, the study became part of the Multicenter Italian Study on Cholelithiasis,23 whereas between 1986 and 1990 it was included in the WHO European Risk Factors Co-ordinated Analysis (ERICA),24 and in the Risk Factors and Life Expectancy Project,25 respectively. In 1994, the BHS was incorporated in the WHO Countrywide Integrated Noncommunicable Disease Intervention project and more recently the data derived from the BHS have also been included in the development of new algorithms for the calculation of the global risk of CVD such as the RISCARD 200026 and the RISKARD 2005.27 The general protocol of the BHS and its substudies have been approved by the Ethical Committee of the University of Bologna, and formal consent was obtained and signed by all participants before inclusion in the study. The occurrence of new fatal and nonfatal events (encoded according to the International Classification of Diseases-9) was recorded every 3 months and included in the database throughout the entire duration of the study, whereas a complete medical examination was performed every 4 years. Morbidity and mortality have been assessed and validated through the review of personal documentation and/or hospital records. The standard visit included personal and family history (lifestyle habits and pharmacological treatments), physical examination (anthropometric measurements, blood pressure, heart and breath rate), fasting blood sample and standard ECG. The blood samples were processed on site by trained personnel and then analysed in the lipid clinic laboratory of the University of Bologna. All the laboratory procedures were standardized according to the Laboratory for Atherosclerosis Research, Institute for Clinical and Experimental Medicine (IKEM), Prague (CZ), responsible for the laboratory procedures of the WHO MONICA project. Blood chemistry parameters included total cholesterol, low-density lipoprotein
(LDL)-cholesterol, total triglycerides, high-density lipoprotein-cholesterol (from 1980), apolipoprotein B, apolipoprotein AI, lipoprotein(a), transaminases, creatinine, creatinine-phosphokinase. Other specific analyses (i.e. erythrocyte fatty acids, serum minerals) and/or instrumental evaluations (i.e. liver ultrasound, carotid intima–media thickness measurement) have been carried out as a part of specific substudies and cooperative projects.22 Physical activity during leisure time was assessed on the basis of a simplified scale administered to the participants as an interview by trained research personnel. Leisure-time physical activity was categorized on the basis of four alternative answers to the question ‘how much physical activity do you engage in during your leisure time?’ The question referred to the past year and the alternatives were as follows: 1. Sedentary leisure time: reading, television, stamp collecting or other sedentary activity. 2. Light leisure-time physical activity: walking, cycling, or other physical activity under at least 4 h per week. 3. Moderate leisure-time physical activity: running, swimming, tennis, aerobic, heavier gardening, or similar physical activity during at least 2 h a week. 4. Heavy training or competitive sport: heavy training or competitions in running, skiing, swimming, football, and so on, which is performed regularly and several times a week. Working physical activity was measured by the question ‘is your daily work physically light or heavy?’. The five alternative answers were as follows: 1. Very light: sitting work (e.g. driving a vehicle, reading, office work, teaching). 2. Light: standing with little muscle activity (e.g. feeding, distribution of medication in a healthcare setting, washing up, precision mechanical work). 3. Moderate intensity: muscular activity with moderate intensity (e.g. walking around, lifting/carrying less than 5 kg, washing, making beds, cleaning, carpenter’s work, childcare). 4. Heavy: muscular work with quite high intensity and increased breathing (e.g. maintenance, heavier service work, handling patients within medical care, sweeping streets, heavier gardening, freighting/unloading goods). 5. Very heavy: muscular activity with high intensity and highly increased breathing (e.g. casting concrete, timbering, shovelling soil/sand, lifting/carrying more than 25 kg). The resulting physical activity intensity has been classified in three separated self-rated categories defined as scarce–null, medium and intense. Afterward the questionnaire was implemented and validated28 by defining
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Leisure-time physical activity and CVD mortality Cicero et al. 561
the correspondence between the above-cited categories and the levels of exercise according to the American College of Sports Medicine and the American Heart Association guidelines.29 In particular, we defined exercise levels as sedentary ¼ moderate-intensity physical activity for less than 30 min on 5 days/week or vigorous-intensity aerobic activity for less than 20 min on 3 days/week; medium ¼ moderate-intensity physical activity between 30 min on 5 days/week or vigorousintensity aerobic activity for 20 min on 3 days/week and moderate-intensity physical activity for more than 60 min on 5 days/week or vigorous-intensity aerobic activity for 40 min on 3 days/week; intense ¼ moderate-intensity physical activity for more than 60 min on 5 days/week or vigorous-intensity aerobic activity for 40 min on 3 days/ week. As regards working physical activity, similar categories were created according to the amount of sweat produced during the exercise,30 a largely accepted evaluation method of physical activity intensity in the years when these data were sampled.31 However, these data were not used to compile this article because of the very small variation of working physical activity intensity in the context of a rural population and the scarce association with the level of the main cardiovascular risk factors.30 Statistical analysis
For this study, we selected from the general BHS database those participants, neither treated with antihypertensive, lipid-lowering drug nor antiplatelet drugs, visited in all population surveys from 1988 to 2000. The primary end point of our study was to assess the relationship between the amount and intensity of physical activity during leisure time and cardiovascular mortality across a period of time from 1988 to 2000. Because most of the population sample carried out a moderate–intense activity, the previously considered categories were further grouped by pooling together individuals with medium and intense physical activity. Sedentary physical activity included all the other individuals. Long-term prognostic significance of physical activity at baseline (1988 population survey) was determined before and after adjustments for well-known and established CVD risk factors such as age, sex, smoking habit, plasma LDL-cholesterol and history of diabetes mellitus. All the analyses were repeated after stratification of participants according to sex and age classes (
