Hygiene Hypothesis May Explain Rise in Coronary Heart Disease

Hygiene Hypothesis May Explain Rise in Coronary Heart Disease: "Hygiene Hypothesis May Explain Rise in Coronary Heart Disease

By Matias A. Loewy

BUENOS AIRES (Reuters Health) Sept 23 - Early childhood viral infections might reduce the risk of later ischemic heart disease by as much as 90%, researchers from Sweden and Finland reported here on Wednesday at the IV World Congress of Pediatric Cardiology and Cardiac Surgery.

According to the investigators, 'improved hygiene in early childhood might partially explain the greatest epidemic of the 20th century, coronary heart disease'.

It is the first time that the so-called 'hygiene hypothesis', which postulates that reduced microbial exposure because of improved sanitation and cleaner lifestyles has facilitated the rise in asthma, allergic disease and multiple sclerosis in the Western world, is linked to the development of heart disease.

Researchers led by Dr. Erkki Pesonen, from the University Hospital in Lund, Sweden, compared 350 patients with unstable angina pectoris or myocardial infarction with paired controls without coronary disease. They all answered a questionnaire about their childhood experience of contagious diseases, specifically whether they had ever had varicella, scarlet fever, measles, German measles, mononucleosis or parotitis.

Childhood contagious diseases were more frequent in the controls, researchers noted. Furthermore, they found a consistent linear trend between the number of childhood infections and the reduction in coronary risk. For instance, two viral infections reduced the coronary risk by 40%, four infections was associated with a 60% decreased risk, and six infections with a 90% reduction in risk.

Dr. Horacio Faella, a pediatric cardiologist at the Garrahan Hospital, Buenos Aires, and member of the Organizing Committee of the meeting, considered the finding to be interesting but preliminary. 'We need to do more studies about the influence of the immune system on the cardiovascular system', he said.

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