Might infection explain the higher risk of coronary heart disease in South Asians? Systematic review comparing prevalence rates with white populations in developed countries

SummaryObjectivesSouth Asians in developed countries such as the UK are at comparatively high risk of coronary heart disease for reasons which are not fully understood. One unexplored hypothesis is more infections in this ethnic group. This study assessed whether the prevalence of infections among South Asians differs from that among White populations of European origin in developed countries.Study designSystematic review.MethodsMedline, Web of Science and Google Scholar databases were searched. In addition, reference lists and citations were reviewed.ResultsTwenty-one studies reported prevalence rates and mean antibody levels of infection with 17 different pathogens or non-specific markers of infection. Among bacterial infections, higher rates of Escherichia coli and Mycobacterium tuberculosis infection were found in South Asians. No consistent differences were found for periodontal pathogens, Helicobacter pylori, Staphylococcus aureus, Chlamydia pneumoniae and Mycobacterium avium. For viral pathogens, higher rates of hepatitis A, hepatitis B and cytomegalovirus; and lower rates of herpes simplex, hepatitis C, human immunodeficiency virus and varicella zoster virus were found among South Asians. No difference was seen in the prevalence of hepatitis G virus in South Asians. Levels of non-specific markers of infection (total immunoglobulin G, endotoxin) were higher in South Asians.ConclusionsThe number of studies was small. Differences in the prevalence of specific infections were found, but the current evidence is insufficient to support or reject the hypothesis under examination. Further studies are warranted.