In the past 30 years, an increased cardiovascular disease (CVD) mortality has been observed in both industrialized and transition countries. The latter countries, such as Croatia, are considered to be in the third stage of epidemiological transition, defined as having 35%-65% of total as CVD mortality, predominantly ischemic heart disease and cerebrovascular disease. The CVD epidemic in transition countries is due to increasing rates of hypertension, obesity, smoking and sedentary lifestyle. Among CVD diagnoses, the most important is coronary heart disease (CHD), which varies in incidence among different ethnic groups and countries. Worldwide, it is estimated that nine potentially modifiable risk factors contribute to more than 90% of myocardial infarctions. Approximately 80%-90% of patients with symptomatic CHD and more than 95% of patients who died from CHD had at least one of the four traditional risk factors (smoking, hypertension, hyperlipidemia, and diabetes).
Little research has been done to quantify the relationship between the prevalence of CHD risk factors and acute myocardial infarction (AMI) in Croatia. In south Croatia, we expected that specific dietary patterns and lifestyle would have favorable effects on CHD risk. Therefore, we have conducted a case-control study to examine the relationship between several CHD risk factors (smoking, hypertension, hyperlipidemia, diabetes, obesity, alcohol, fruit and vegetable consumption, and physical activity) in AMI patients and persons without previously known CHD in south Croatia.
We took part in the INTERHEART study over 4 years (1999-2002). Cases were all eligible patients with first AMI admitted to the Coronary Care Unit, Split University Hospital. Within one month of admission at least one control was recruited and matched to every AMI case by age (+/-5 years) and sex. Exclusion criteria were the same for cases and controls. Structured questionnaires were administered and physical examinations were undertaken in the same manner in cases and controls. Relationship between the risk factors and AMI are presented by odds ratios, estimated by multivariate logistic regression.
During the study period 263 cases and 264 controls were enrolled. The proportion of males (74.6%) was threefold that of females. The highest relative difference between the case and control risk factors was noted for current smoking (16.6%; p<0.001), diabetes (10.5%; p<0.001), hypertension (9.0%; p=0.038) and abdominal obesity (18.5%; p<0.001). Ever smoking accounted for 75% higher AMI risk than non-smoking (OR 1.74; p=0.006), while current smoking accounted for a 2.6 time higher risk in comparison to non-smoking (OR 2.58; p<0.001). Diabetes had a threefold risk (OR 2.83; p<0.001). Hypertension accounted for a 70% higher risk (OR 1.68; p=0.007). Abdominal obesity was associated with a significantly increased AMI risk (OR 1.96; p=0.007). The highest apolipoprotein B/apolipoprotein A-1 (ApoB/ApoA-1) tertile accounted for nearly 2.5-fold risk (OR 2.23; p=0.005). Physical activity and daily consumption of fruits and vegetables did not prove to be significant factors in Croatia. Regular consumption of alcohol decreased coronary risk by approximately one third (OR 0.63; p=0.044).
The most important AMI risk factor in south Croatia is current smoking, followed by diabetes, abnormal ApoB/ApoA-1 ratio, abdominal obesity, and hypertension. A protective risk factor is alcohol consumption, while physical activity and fruit and vegetable consumption are less important. These results are similar to the global INTERHEART data showing that most of AMI risk could be predicted with nine simple, measurable risk factors worldwide. Protective measures for CHD, including increased daily consumption of fruits and vegetables, moderate physical activity and particularly smoking cessation should be implemented worldwide. In specific regions such as south Croatia, moderate alcohol consumption (mostly red wine) may be included among protective measures due to sociologic and cultural reasons.