The findings, published in ESC Heart Failure, a journal of the European Society of Cardiology(ESC), reveals that preventing iron deficiency could prevent 10% of new coronary heart disease cases arising within a decade of middle age.
Previous research has connected iron deficiency to worse outcomes in people with cardiovascular disorders such as heart failure, including hospitalizations and death. Intravenous iron treatment improved symptoms, functional capacity, and quality of life in FAIR-HF trial participants with heart failure and iron deficiency. Based on these findings, the FAIR-HF 2 study is looking into the effect of intravenous iron supplementation on the risk of death in heart failure patients.
The current investigation aimed to see if there is a link between iron deficiency and outcomes was also seen in the general population.
The research involved 12,164 people from three European population-based cohorts. The median age was 59 years, and women were 55 percent. During the baseline study visit, cardiovascular risk factors and comorbidities such as smoking, obesity, diabetes, and cholesterol were evaluated using a comprehensive clinical assessment that included blood samples.
Individuals were categorized as iron deficient or not based on two criteria: 1) absolute iron deficiency, which only includes stored iron (ferritin); and 2) functional iron deficits, which includes iron in storage (ferritin) as well as iron in circulation for use by the body (transferrin).
The study author Dr. Benedikt Schrage of the University Heart and Vasculature Centre Hamburg explained:
“Absolute iron deficiency is the traditional way of assessing iron status but it misses circulating iron. The functional definition is more accurate as it includes both measures and picks up those with sufficient stores but not enough in circulation for the body to work properly.”
Participants were tracked for incident coronary heart disease and stroke, cardiovascular disease death, and all-cause death. After adjusting for age, gender, smoking, cholesterol, blood pressure, diabetes, body mass index, and inflammation, the researchers looked at the link between iron deficiency and incident coronary heart disease, stroke, cardiovascular mortality, and all-cause death rates. Participants who had a history of coronary heart disease or stroke at the start of the study were excluded from the incident disease analysis.
At the start of the study, 60 percent of patients had absolute iron deficiency and 64 percent had functional iron deficiency. There were 2,212 deaths (18.2 percent) with a median follow-up of 13.3 years. A total of 573 people (4.7 percent) died as a result of a cardiovascular disease. Coronary heart disease and stroke were diagnosed in 1,033 (8.5 percent) and 766 (6.3 percent) of patients, respectively.
When compared to no functional iron deficiency, functional iron deficiency was related with a 24 percent increased risk of coronary heart disease, a 26 percent increased risk of cardiovascular mortality, and a 12 percent increased risk of all-cause death rates. Absolute iron deficiency was linked to a 20 percent increased risk of coronary heart disease compared to no absolute iron deficiency, but not to death. There was no link found between iron status and incident stroke.
The researchers determined the population attributable fraction, which estimates the proportion of occurrences that would have been prevented during a ten-year period if all individuals had the risk associated with those without iron deficiency at baseline. Age, gender, smoking status, cholesterol, blood pressure, diabetes, body mass index, and inflammation were all adjusted in the models. Within a 10-year period, functional iron deficiency was responsible for 5.4 percent of all deaths, 11.7 percent of cardiovascular deaths, and 10.7 percent of new coronary heart disease diagnoses.
“This analysis suggests that if iron deficiency had been absent at baseline, about 5% of deaths, 12% of cardiovascular deaths, and 11% of new coronary heart disease diagnoses would not have occurred in the following decade,” according to Dr. Schrage.
“The study showed that iron deficiency was highly prevalent in this middle-aged population, with nearly two-thirds having functional iron deficiency,” Dr. Schrage added.
“These individuals were more likely to develop heart disease and were also more likely to die during the next 13 years.”
But “This was an observational study and we cannot conclude that iron deficiency causes heart disease.”
Dr. Schrage suggested that future research should investigate these connections in younger and non-European cohorts. As he stated:
“If the relationships are confirmed, the next step would be a randomized trial investigating the effect of treating iron deficiency in the general population.”
Source: ESC Heart Fail. 2021. DOI: 10.1002/ehf2.13589
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