IJCS | Volume 32, Nº2, March/April 2019

DOI: 10.5935/2359-4802.20190004 163 REVIEW ARTICLE International Journal of Cardiovascular Sciences. 2019;32(2)163-176 Mailing Address: Zeng B Department of Cardiology, Renmin Hospital of Wuhan University. Postal Code: 430060, Wuhan Shi, Hubei Sheng - China. E-mail: zengbinwhu@163.com Risk Factor Differences in Acute Myocardial Infarction between Young and Older People: A Systematic Review and Meta-Analysis Liu L ei a nd Zeng Bi n Renmin Hospital of Wuhan University, Wuhan Shi, Hubei Sheng - China Manuscript received July 22, 2017; revised manuscript on January 23, 2018; accepted on March 03, 2018. Myocardial Infarction; Risk Factors; Aged; Review; Meta-Analysis. Keywords Abstract Acute myocardial infarction (AMI) is less frequent in young individuals (≤ 45 years) than in older ones (> 45 years). Young AMI patients differ from older AMI patients in different ways. This article aims to assess the differences between young and older AMI patients. A search was made in the database of Cochrane Library, PubMed, BioMed Central and Embase, sence their establishment to December 2016, using the key words: risk factors, clinical characteristics, acute myocardial infarction and young. Meta-analysis was performed by using the Review Manager 5.3 software, pooled odds ratios and 95% confidence intervals were used to assess the strength of differences. Eight studies with fairly quality, enrolling 13,358 patients in the analysis. Compared with older AMI patients, young AMI patients had a higher rate of smoking and obesity (OR = 2.71,95%CI:1.87 to 3.92; OR = 1.76,95%CI:1.13 to 2.74), higher rate of family history of coronary artery disease and alcohol consumption (OR = 2.36,95%CI:1.22 to 4.59; OR = 1.76,95%CI:1.04 to 2.97). Moreover, Young AMI patients had a lower rate of hypertension and diabetes mellitus (OR = 0.52,95%CI:0.37 to 0.73; OR = 0.58,95%CI:0.50 to 0.67). No significant differences were observed in hyperlipidemia, a subgroup data- analysis showed a higher total cholesterol, triglyceride lipase, and low-density lipoprotein levels (p < 0.05), and lower levels of high-density lipoprotein (p < 0.01) in young AMI patients. Smoking, family history of coronary artery disease, obesity and alcohol consumption are the most main risk factors of AMI among young individuals, and young AMI patients have better prognosis than older ones. Introduction Cardiovascular disease (CVD) is a global health problem that has reached epidemic proportions in both developed and developing countries. 1 Even though the rates of death caused by CVD have declined, yet the burden of disease remains high. Mortality data have showed that CVD accounted for almost 32.8% of all deaths, i.e., 1 of every 3 deaths was caused by CVD in the United States. CVD has become the leading cause of death in both developed and developing countries. 2,3 Acute myocardial infarction(AMI) is less frequent in young adults (≤ 45 years) than in older individuals (> 45 years) as it occurs in only 2% to 6% in the younger population. 4 In recent years, the rate of AMI in young adults has begun to rise. Studies showed that young AMI patients differed fromolder AMI patients in several ways, including risk factors, clinical characteristics, coronary angiographic characteristics andprognosis. 5 AMI in young individuals can cause death and disability in the prime of life, in addition to being an increasing economic burden for both the patients’ family and the government. Because of the potential of premature death and long-termdisability in young AMI patients, clinical interest in young adults is increasing.6 Identifying the major risk factors for AMI in this group of young individuals is of vital significance to develop effective prevention strategies. Young AMI patients have different clinical characteristics and pathophysiology when compared to older patients. 7 Previous studies reported that smoking, diabetes mellitus, family history of CAD, hypertension, hyperlipidemia and obesity contribute to the set of main