Cardiovascular Disease in Soccer Referees
Condition: Cardiovascular Diseases
MeSH terms: Cardiovascular Diseases
Study type: Observational

Summary: 
      Although the mortality rate among soccer players is low, it causes much impact on the entire
      community and is a fascinating conundrum. The aim of this study was to evaluate the
      cardiovascular risk of soccer referees, to describe the frequency of cardiovascular risk
      considering age groups younger and older than 35 years old and to relate the Framingham and
      PROCAM indices for the comparison of cardiovascular risk in soccer referees. 50 referees of
      Paulista Soccer Federation were subjected to clinical and laboratory based evaluations at the
      Center for Sports Health at the Faculty of Medicine of ABC, and divided into two groups:
      lower and higher than 35 years of age.
    

Detailed description: 
      This is a cross-sectional study performed in a non-probabilistic sample for convenience,
      derived from information collected from medical records of the Medical Statistics Service.
      Data were obtained through clinical evaluation information and subsidiary examinations of 50
      high performance field soccer referees of the Paulista Soccer Federation (PFF), during a
      pre-season training period of the 2009 Brazilian soccer championship.

      Emphasis was especially placed on exposure to risk factors for coronary artery disease,
      conceivably more responsible for sudden death, when congenital heart disease was excluded.

      All subjects were acquiesced to clinical and laboratory evaluations at the Center for Health
      in Sport of the Faculty of Medicine of ABC (FMABC). The referees were split into two age
      groups, according to the median of their ages. One of the groups consisted of trained
      individuals < 35 years old while the other group was made up of referees > 35 years old.

      Family history: Occurrence of one or more relatives with disease or death from cardiac
      disease aged less than 50 years; Report of cardiomyopathy, coronary artery disease, Marfan
      syndrome or long QT syndrome, severe cardiac arrhythmias, or other cardiovascular diseases.

      Personal history: Syncope or pre-Syncope; Chest pain or discomfort; Lack of air or fatigue
      disproportionate to the effort made; Palpitations or irregular heartbeat.

      Physical examination: Physical and/or ocular signs of Marfan Syndrome; Decreased femoral
      artery pulses or "tardus"; meso- or telo- systolic murmurs; Second abnormal heart sound
      (single or with fixed unfolding with breathing); Heart murmurs (grade 2/6 systolic or
      diastolic of any intensity); Irregular heart rate; Bilateral blood pressure greater than
      140/90 mmHg in more than one measurement.

      Biochemical tests: High density lipoprotein (HDL), low density lipoprotein (LDL), very low
      density lipoproteins (VLDL), triglycerides (TG) and fasting blood glucose levels (Glic) were
      analyzed. The biochemical blood tests were processed by the Clinical Laboratory of FMABC,
      certified by controlab and ANVISA. The reference standards were considered according to the
      Guidelines of the Brazilian Society of Cardiology.

      Ergospirometry: The following parameters were analyzed: Ergospirometry (Ergo), Maximum heart
      rate (HRmax), Maximum oxygen consumption (VO2max) and Anaerobic threshold (LA). The
      ergospirometric data were obtained through the Centurion 200 Treadmill and Micromed® BRA ECG.
      Protocol: start with 10 km/h - 1% inclination and increase of 1 km every minute. Gas
      analyzer: Vmax, Encore 29 c, Sensormedics®, USA. Program 20-21. Gases in two torpedoes: (1) -
      oxygen (O2); 26% and (2) - Carbon Dioxide (CO2): 4%, oxygen (O2) = 16% and Nitrogen (N2).

      Echocardiogram: Two-dimensional echocardiogram (ECO) with Doppler was obtained by Esaote®
      model AV3 Partner with 2.5 MHz transducer with color flow mapping.

      Electrocardiogram: The electrocardiographic tracings were performed by the Ecafix®
      CardioPerfect 5.0 device coupled to a microcomputer with compatible HD and a 1.4 MB drive 60
      Hz filter. Approved by the Food and Drug Administration (FDA), the records were taken at
      rest, on days when they had not performed exercises, and according to the best clinical
      practice. The interpretation of the ECG abnormalities was completed by an experienced
      specialist and according to the criteria established by Corrado et al., for which they were
      classified into two categories:

        -  Group 1: commonly observed in trained athletes (over 80%) sinus bradycardia,
           first-degree AV block, V1 notch QRS or incomplete right bundle branch block, early
           repolarization, LVH criteria according to voltage increase in V5 and V6 consistent with
           the athlete's age, ethnicity and degree of physical fitness, and which does not require
           additional testing.

        -  Group 2: less common ECG changes (less than 5%) and need to be better evaluated to
           exclude cardiovascular diseases: T-wave inversion, ST-segment depression, pathological
           Q-waves, left atrial enlargement, QRS shift to the left, left/right anterolateral
           hemiblock, right QRS deviation/left posterolateral lower hemiblock, right ventricular
           hypertrophy, complete left or right bundle branch block, long or short QT interval,
           early ventricular repolarization Brugada like, ventricular arrhythmias.

      Framingham and PROCAM indexes The risk of developing cardiovascular disease is contingent on
      multiple variables that interrelate with each other, increasing the probability of developing
      atherosclerotic coronary disease. Each of the risk factors is assigned a value that reflects
      greater or lesser potential impact on the development of cardiovascular disease and the
      implementation of preventive measures, and likelihoods, when applied early, to avert the
      onset of this disease.

      The Framingham risk index was constructed based on the Framingham study, a prospective
      observational survey developed in the small northeastern city of the United States of
      America. This study evaluated blood pressure, smoking, lipid profile and other
      characteristics of 5,300 individuals of different ethnicities residing in Framingham, aged
      between 30 and 74 years at the time of the initial observation, as well as their causes of
      death and disease.

      This index analyzes the cardiovascular risk in relation to the chance of developing stroke,
      acute myocardial infarction and cardiovascular death for the subsequent 10 years. The
      Framingham cardiovascular risk index has the characteristic of categorizing the variables
      into a smaller number of sections or sections without significant differentiation of body
      mass, age, gender, total cholesterol, HDL, presence or absence of smoking and Diabetes
      Mellitus, systolic and diastolic blood pressure values. Total points represent the percentage
      of cardiovascular risk (acute myocardial infarction, stroke and cardiovascular death) in the
      following 10 years.

      The PROCAM index is a cardiovascular risk index based on a European study that commenced in
      1979 and was completed in 1985. A total of 5159 individuals, all males, aged 35 to 65 years.
      The PROCAM index identified the following variables: age, LDL-cholesterol, HDL-cholesterol,
      Triglycerides (this is the only criterion that considers it directly), smoking, Diabetes
      Mellitus, systolic blood pressure and family history (this variable is considered only by
      this risk score). The total points represent the risk of cardiovascular disease (acute
      myocardial infarction, stroke and cardiovascular death) in the ensuing 10 years.
    

Intervention name(s): Less than 35 years old; Greater than or equal to 35 years
Intervention type(s): Other; Other
Intervention description(s): Clinical and laboratory evaluations; Clinical and laboratory evaluations
Observational model: Case-Only
Time perspective: Retrospective
Sampling method: Non-Probability Sample
Study population: 
        50 high performance field soccer referees of the Paulista Soccer Federation (PFF), during a
        pre-season training period of the 2009 Brazilian soccer championship.