The new study suggests infections in childhood - such as typhoid fever, measles and chicken pox - increase risk of early heart attack in adulthood.
The study was presented at the Acute Cardiovascular Care conference in Vienna on Saturday, October 17th, by Andriany Qanitha, a PhD candidate at the Academic Medical Centre in the Netherlands.
Qanitha notes that in Indonesia, where the study took place, cardiovascular disease (CVD) accounts for 31.9% of all deaths.
A heart attack occurs when the blood supply to the heart is cut off; during this time, cells in the heart muscle that do not get enough oxygen through the blood begin to die. The more time that passes without restored blood flow, the greater the damage to the heart.
Because infectious diseases, including typhoid fever, measles, chicken pox, bronchitis, tuberculosis and dengue fever are common in children in Indonesia, Qanitha and her team "hypothesized that infections experienced in childhood and adolescence might adversely affect the vasculature and initiate atherosclerosis, leading to premature acute coronary syndromes (ACS) or heart attacks."
To further investigate, the researchers conducted a population-based case-control study including 153 patients with ACS before 56 years of age, and 153 controls with no history of ACS.
They defined "severe infection" as fever for 3 days or more, or hospitalization for infectious disease.
Three-fold higher chance of ACS for those with childhood infections
Because there is not any reliable registry data in Indonesia on infection-related hospitalization or antibiotic prescription, the team employed a detailed questionnaire in addition to interviewing the patients and controls, as well as their family members.
- Symptoms of heart attack include chest pain; discomfort in arms, back or neck; shortness of breath and nausea
- In the US, 15% of people who have a heart attack will die
- Each year in the US, about 735,000 Americans have a heart attack.
Through the questionnaire, the researchers were able to gather information on infection history during four periods of early life:
- 0-5 years (infancy and preschool)
- 6-13 years (elementary school)
- 14-17 years (junior high school)
- 18-21 years (senior high school).
From the data they gathered, the researchers were able to calculate an infection score, ranging from 0-4. They also recorded data on a number of factors, including age, sex, occupation, monthly income, educational level, dietary pattern, physical activity, smoking status and family health history.
Results showed that study subjects who experienced infection in childhood and adolescence had a three-fold higher likelihood of experiencing ACS in later life.
"One explanation is that infection initiates chronic inflammation and atherosclerosis in the arteries," says Qanitha. "It could be that infection modifies CVD risk factors and leads to ACS."
"CVD risk factors are rising rapidly in South-East Asia, particularly in young people. Most Indonesian CVD patients are under 56 years old and still economically productive. This very young CVD onset raises the question of whether local circumstances may play a role."
'Combined strategy needed to tackle disease'
After accounting for CVD risk factors - such as HDL cholesterol levels, smoking status, diabetes, blood pressure and use of blood pressure medications - the researchers concluded that the risk of premature ACS in patients with childhood infections increased with more CVD risk factors.
But do these results apply to other areas of the world? After all, the study was conducted in Makassar, Indonesia, where the lifestyle and environment differ from that of the US, for example.
Qanitha suggests, at the very least, their "findings may apply to other countries in South-East Asia where infectious disease is still prevalent." She continues:
"Here, governments and policymakers should have a combined strategy for tackling infectious disease and cardiovascular disease. Early-life infection may be a relatively unknown contributing factor in ACS occurrence."
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