Medical Bulletin 12/ April/ 2024

A study conducted by researchers in Sweden and published in the journal New England Journal of Medicine determined whether the standard practice of prescribing beta-blockers after a heart attack improved the risk of a future cardiovascular event or death.

Heart attacks are a leading cause of death, and according to the American Heart Association (AHA), more than 600,000 people experience their first heart attack each year. Beta-blockers are commonly prescribed following a heart attack to reduce the risk of a subsequent cardiovascular event. While beta-blockers are helpful for many reasons and can lower heart rate and blood pressure, there are some drawbacks to taking beta-blockers.

The REDUCE-AMI trial investigated whether beta-blockers decrease the risk of death or recurrent heart attacks in individuals with normal ejection fraction post-heart attack. Running from September 2017 to May 2023, the trial enrolled 5,020 participants from 45 healthcare centres. Participants had normal ejection fraction and underwent coronary angiography. They were randomly assigned beta-blockers (metoprolol or bisoprolol) for long-term treatment, with a median follow-up of 3.5 years.

The results showed that 7.9% of beta-blocker group had death or new heart attack, slightly lower than 8.3% in no-beta-blocker group. Beta-blockers didn't significantly reduce all-cause death: 3.9% in beta-blocker group vs. 4.1% in no-beta-blocker group.

The findings revealed no significant difference in cardiovascular outcomes between the beta-blockers group and the no-beta-blockers group.

“I do think the guidelines will be changed, and the prescription of beta-blockers will go down in patients with a heart attack (myocardial infarction) and a preserved (or normal) heart function, that is, about half of all patients with heart attack. However, for patients with reduced heart function or heart failure, we know that beta-blockers improve survival and symptoms. As a patient, you should never stop taking beta-blockers without first talking to your doctor,” said Tomas Jernberg, MD, PhD, a cardiology professor and Head of the Department of Clinical Sciences at Karolinska Institute in Sweden and Lead study investigator.

Reference: Troels Yndigegn, M.D., Bertil Lindahl, Ph.D., Katarina Mars, M.D., Joakim Alfredsson, Ph.D., Jocelyne Benatar, Ph.D., Lisa Brandin, Ph.D., David Erlinge, Ph.D, et al.; Beta-Blockers after Myocardial Infarction and Preserved Ejection Fraction; Journal: New England Journal of Medicine; DOI: 10.1056/NEJMoa2401479

Is Vit. D and probiotics beneficial for people with schizophrenia?

In a study published in the journal Neuropsychopharmacology Reports, researchers indicated that taking probiotics plus vitamin D supplements may improve cognitive function in individuals with schizophrenia.

Schizophrenia is among the most common severe mental disorders and one of the top 25 leading causes of disability around the world. Medications that block the dopamine system are effective in delusions and hallucinations associated with the disorder. However, they are less effective in the improvement of cognitive and motivational disorders. Taking antipsychotic drugs, which have anticholinergic and anti-histaminergic effects, increases the prevalence of gastrointestinal diseases. Previous studies have suggested the synergistic effects of combined vitamin D and probiotics on mental health. It has been hypothesised that probiotics can increase vitamin D levels. In addition, probiotics improve the expression of vitamin D receptors.

For the study, 70 adults with schizophrenia were randomised to take a placebo or probiotic supplements plus 400 IU vitamin D daily for 12 weeks. Severity of the disease and cognitive function were evaluated by tests called the Positive and Negative Syndrome Scale (PANSS) and the 30-point Montreal Cognitive Assessment (MoCA), respectively.

The results showed that probiotic/vitamin D supplementation significantly increased MoCA score compared to the placebo-receiving group. Also, the number of patients with MoCA score ≥ 26 significantly increased in probiotic group. On the other hand, intervention with probiotic-containing supplement decreased PANSS score.

The findings revealed that co-administration of probiotics and vitamin D showed beneficial effects on the improvement of cognitive function in schizophrenic patients.

“Probiotics may be a novel way to treat mental disorders by regulating gut microbiota,” said corresponding author Gita Sadighi, MD, of the University of Social Welfare and Rehabilitation Sciences.

Reference: Aida Mohammadi, Gita Sadighi, Ali Nazeri Astaneh, Maryam Tajabadi-Ebrahimi, Tahereh Dejam; Co-administration of probiotic and vitamin D significantly improves cognitive function in schizophrenic patients: A double-blinded randomized controlled trial; Journal: Neuropsychopharmacology Reports; https://doi.org/10.1002/npr2.12431

Does obesity increase risk of iron deficiency?

According to a study by nutritional scientists at the University of Leeds, children and young people who are overweight or obese are at significantly higher risk of iron deficiency.

The study was published in the journal BMJ Global Health.

Deficiencies in micronutrients contribute to impaired immune function, poor growth and physical development and increased morbidity and mortality in children. Among the micronutrients, deficiencies in iron, zinc and vitamin A (VA) remain particularly prevalent and causally associated with adverse health outcomes for children. Iron deficiency (ID) and ID anaemia (IDA) are major global health challenges affecting more than 1.2 billion people worldwide.

In the study, Researchers from the School of Food Science and Nutrition examined thousands of medical studies from 44 countries involving people under the age of 25 for observational studies assessing micronutrient status (blood, serum or plasma levels of iron, zinc or VA biomarkers) and weight status (body mass index or other anthropometric measurement).

The researchers found that iron deficiency was associated with both underweight and overweight children and adolescents. By contrast, zinc and vitamin A deficiencies were only observed in children who were undernourished, which concluded that iron deficiency in overweight children is likely due to inflammation disrupting the mechanisms that regulate iron absorption.

The findings revealed that iron, zinc deficiencies were commonly associated with undernutrition in children and young people. Overnutrition increased the risk of ID, but not zinc deficiency, with an inverted U-shaped relationship observed between iron status and body weight.

“The relationship between undernutrition and critical micronutrients for childhood growth and development is well established, but less is known about the risk of deficiencies in iron and zinc in children and adolescents who are overweight or obese, making this a hidden form of malnutrition. Our research is hugely important given the high prevalence of obesity in children. We hope it will lead to increased recognition of the problem by healthcare practitioners and improvements in clinical practice and care,” said Xiaomian Tan, a Doctoral Researcher in the University of Leeds' School of Food Science and Nutrition and lead author of the study.

Reference: Xiaomian Tan, Pui Yee Tan, Yun Yun Gong, Bernadette Moore; Overnutrition is a risk factor for iron, but not for zinc or vitamin A deficiency in children and young people: a systematic review and meta-analysis; Journal: BMJ Global Health; DOI: 10.1136/bmjgh-2024-015135