Title

Risk factors for acute myocardial infarction in young adults (> 15 - < 45 years) of Karachi, Pakistan

Date of Award

2003

Document Type

Thesis

Degree Name

Master of Science in Epidemiology & Biostatistics (MSc Epidemiology & Biostats)

Department

Community Health Sciences

Abstract

The World Health Organization (WHO) attributes 30% of all global deaths (i.e., 15.3 million) as well as 10.3% of the total DALYs lost in 1998 to Cardiovascular Diseases (CVD). The low and middle-income countries accounted for 78%o of all deaths and 86.3% of Disability Adjusted Life Years (DALYs) lost-attributable to CVD- world-wide in 1998. The burden of ischemic heart disease (IHD) is rising in epidemic proportions in the South Asian (SA) countries. It is now well known that coronary artery disease (CAD) tend to occur in younger age in SA than in other populations of the world. Studies of SA immigrants in various parts of the world have documented this increased predisposition to CAD in comparison with the native population in these regions. The reason for this increased risk is unclear. We performed an epidemiological study in an urban area of Pakistan to find out major risk factors for Acute Myocardial Infarction (AMD in young adults. To the best of our knowledge no major analytical study has been done in Pakistan on the risk factors associated with AMI in young patients. Therefore, there was a great need to do a well-designed case control study to identify risk factors for AMI in young adults (< 45 years). Our study was conducted to determine the risk factors for AMI among young adults in Karachi. A 1:1 matched case control study was designed and a sample of 193 cases aged 15 to 45 years with a diagnosis of AMI and same No. of age, sex, and neighborhood matched controls were achieved during August 2001 to June 2002. Majority of cases were enrolled from the National Institute of Cardiovascular Diseases (NICVD), Karachi. The study had an ethical approval from the Ethical Review Committee of the Aga Khan University. A pre-tested questionnaire in Urdu, after taking informed consent, was administered. We collected the following data: body mass index, waist-hip ratio, systolic and diastolic blood pressure, smoking status, history of diabetes, hypertension, level of education, income level, ghee (clarified butter) in cooking, meat consumption, physical III activity, parental consanguineous marriage, family history of cardiovascular disease, and blood samples for glucose (fasting, random) and serum lipid profile. Conditional logistic regression analysis was performed to determine the independent factor associated with AMI. AMI is defined according to the WHO criteria based on the presence of at least two of the following three criteria: (1) A clinical history of Ischemic-type chest discomfort/pain (2) Changes on serially obtained electrocardiographic tracings (3) A change in serum cardiac enzymes. The mean age of subjects was 39 years (SD ± 4.9 years); 326 (84.45%) subjects were male and 60 (15.54%) were female. We found that use of ghee (saturated fat) in cooking (adjusted odd ratio (aOR) 5.54 [95% CI 2.27 - 13.50], smoking cigarettes (aOR 4.46) [95% CI 2.24 - 9.61], increased of waist to hip ratio > 0.9 cm (aOR 3.79) [95% CI 1.49 - 9.62], low Vs high monthly income (Rs. 5000) (aOR 3.31) [95% g 1.48 - 7.37] and parental consanguineous marriages (aOR 2.98) [95% CI 1.23 - 7.20] were all independent risk factors for AMI in young adults of Karachi. In univariate analysis, as compared to controls, cases were more likely to have paternal history of heart disease as compared to controls (OR 1.81) [95% Cl 1.06 - 3.08], first degree relative as a patient of hypertension as compared to controls (OR 1.55) 195% Cl 1.02 - 2.361, abnormal level of cholesterol (> 200 mg/dl) as compared to controls (OR 2.78) 195% CI 1.69 - 4.561, abnormal level of LDL (>130 mg/dl) as compared to controls (OR 3.75) [95% Cl 1.24 - 11.99], and abnormal blood glucose fasting level (>110 mg/dl) (OR 4) [95% Cl2.27 - 7.04]. Programs directed at reducing consumption in ghee (saturated fat), tobacco control programmes (especially targeting teen age population), prevention and control of obesity, improving glucose tolerance, cholesterol screening programs, and improving the level of education are likely to have a profound effect on the burden of premature AMI in Karachi. The association of consanguineous marriage with AMI is being reported for the first time, and deserves further study.

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