Unstable housing and homelessness are associated with a two-fold greater chance of being re-infected with SARS-CoV-2 compared to those who are securely housed, as demonstrated by the results of a new study.

The study was published in the journal Clinical Infectious Diseases, Led by researchers at Boston Medical Center, the data indicate that unstable housing was the only demographical factor associated with re-infection despite the presence of antibodies from the first infection. The findings demonstrate that potentially high levels of SARS-CoV-2 exposure can overcome robust immune responses, and continuing to follow COVID-19 guidelines may help prevent high-risk SARS-CoV-2 exposure among individuals who are experiencing housing insecurity.

“Most individuals with a previous SARS-CoV-2 infection seem to be protected from the virus for many months or even longer, yet some individuals can become infected again with the virus only a few months later,” said Manish Sagar, MD, an infectious diseases physician at Boston Medical Center.

Manish added, “We conducted this study to understand whether cases of re-infection with SARS-CoV-2 are associated with any demographic characteristics or if reinfection is due to a deficiency in the patient’s immune response.”

Using electronic medical record data from Boston Medical Center patients, individuals who tested positive for SARS-CoV-2 who tested positive again for SARS-CoV-2 after at least 90 days after initial infection were included in the study cohort (n=75).

All individuals that tested negative at least 90 days after an initial SARS-CoV-2 infection were included and classified as the convalescent group (n=1,594). No individuals in this study received a COVID-19 vaccine given that the data was collected prior to the public availability of these vaccines.

The analysis showed that the only demographical factor associated with re-infection was unstable housing and/or homelessness, suggesting that individuals who are homeless are more at risk for re-infection than those with a stable living environment.

The data also showed no significant differences in the antibodies between the re-infection and convalescent groups, and individuals who were re-infected still had SARS-CoV-2 antibodies present, suggesting that exposure to repeated and/or high levels of the virus may be able to overcome the immune responses.

New surprising information has been revealed by researchers at Georgia State, in a first-of-its-kind study, about the relationship between neuron activity and blood flow deep in the brain, as well as how the brain is affected by salt consumption.

When neurons are activated, it typically produces a rapid increase of blood flow to the area. This relationship is known as neurovascular coupling or functional hyperemia, and it occurs via dilation of blood vessels in the brain called arterioles. Functional magnetic resource imaging (fMRI) is based on the concept of neurovascular coupling: experts look for areas of weak blood flow to diagnose brain disorders.

However, previous studies of neurovascular coupling have been limited to superficial areas of the brain (such as the cerebral cortex) and scientists have mostly examined how blood flow changes in response to sensory stimuli coming from the environment (such as visual or auditory stimuli). Little is known about whether the same principles apply to deeper brain regions attuned to stimuli produced by the body itself, known as interoceptive signals.

To study this relationship in deep brain regions, an interdisciplinary team of scientists led by Dr Javier Stern, professor of neuroscience at Georgia State and director of the university’s Center for Neuroinflammation and Cardiometabolic Diseases, developed a novel approach that combines surgical techniques and state-of-the-art neuroimaging.

The team focused on the hypothalamus, a deep brain region involved in critical body functions including drinking, eating, body temperature regulation, and reproduction. The study, published in the journal Cell Reports, examined how blood flow to the hypothalamus changed in response to salt intake.

“We chose salt because the body needs to control sodium levels very precisely. We even have specific cells that detect how much salt is in your blood,” said Stern. “When you ingest salty food, the brain senses it and activates a series of compensatory mechanisms to bring sodium levels back down.”

The body does this in part by activating neurons that trigger the release of vasopressin, an antidiuretic hormone that plays a key role in maintaining the proper concentration of salt. In contrast to previous studies that have observed a positive link between neuron activity and increased blood flow, the researchers found a decrease in blood flow as the neurons became activated in the hypothalamus.

The findings raise interesting questions about how hypertension may affect the brain. Between 50 and 60 per cent of hypertension is believed to be salt-dependent — triggered by excess salt consumption.

A food allergy can be terrifying at times. A minor reaction can involve itching, swelling, and stomach-ache. But sometimes even with a mild one, at some point you may experience a severe reaction ie. ‘Anaphylaxis’ – which is a state of shock, defined as a reaction involving two of the body’s organs. It is characterized by symptoms like wheezing, dizziness, and vomiting. The pulse can slow, blood pressure can drop, and the airways can close. In an alarming number of people in the last few years, it has been fatal.

A food allergy is when the body’s immune system reacts upon any specific food. It could be mild, moderate, or severe. Symptoms of allergic reactions could appear within few minutes to several hours after eating the food to which body is allergic. Although symptoms of an allergic reactions may vary from one individual to another, the commonest symptoms are, hives (reddish or swollen patches on skin), Diarrhea, rashes on skin, stomachache, vomiting, runny nose and so on. Allergic reactions can also appear life threatening. Severe allergic reactions may also be seen as low blood pressure, difficulty in swallowing, swelling of lips, loss of consciousness, low pulse rate.

In India, food allergy is estimated around 3-4% of population, but it is more prevalent in children as compared to adults. Food allergies are treatable only by eliminating the allergic food and its products from the diet. It is very important for a physician to know whether a person gets an allergic reaction repeatedly after eating a particular food or its product. At the same time, self-analysis to recognize the appearance of any allergic reactions helps in planning a good line of treatment. If unable to detect/ diagnose through a medical history of the patient, then an allergist may ask to conduct few diagnostic tests, which help in identifying the food allergy. These tests may include few blood tests, skin prick test or an oral food challenge.

Elimination Diet is also commonly practiced by Physicians with the help of registered Dietitians. People are asked to eliminate the food and food products which cause allergic reactions. It is done on a trial-and-error basis. Most of the times avoiding the culprit food and its products solves the problem at the symptomatic level. Also, in few people it is seen that elimination of culprit food and its products only for certain period gives a lot of symptomatic relief, and once they are stable, reintroducing those food and its products can be tolerated.

In cases where in Elimination Diet fails, medical intervention must be considered after consulting a Physician or an Allergist. Steroid Therapy or Antihistamines are prescribed by practicing doctors. It is always said that precaution and prevention is always better than cure. But unfortunately, there are no preventive measures to avoid food allergy.

Many-a-times it is seen that people do not understand the difference between a food aversion and an allergy. For instance, one may not like milk or has an aversion towards Milk and hence may consider it as being “allergic”; but they may consume Curd, Paneer or Buttermilk that they like. In this instance, person has an aversion towards Milk not that he/she is allergic to it. As allergic reaction develops not only with food but also with its products. One must understand this carefully.

Now-a-days, Gluten allergies are one of the commonest topics of discussion. Gluten is a component found in Wheat, Rye, and Barley. Gluten intolerance is seen amongst few people due to deficiency of an enzyme which helps in the digestion Gluten. These patients develop severe stomachache, vomiting or Diarrhea after eating foods which contains Gluten. This condition is also named as “Celiac Disease”. In Celiac Disease, the patient can’t tolerate anything made up of Wheat, Rye, and Barley. Medical Nutrition Therapy plays a very vital role in treating Celiac Disease. These patients are advised a Gluten –Free Diet by registered Dietitians. In short, it is important to diagnose the allergy and then address it to avoid any kind of mild or fatal consequence. Speak to your healthcare provider if you often experience any food allergies.

The author is a clinical nutritionist, Fortis Hospital Mulund

According to a study led by an international team of researchers, going to sleep between 10:00 and 11:00 pm is associated with a lower risk of developing heart disease compared to earlier or later bedtimes.

The study was published in the European Heart Journal – Digital Health, a journal of the European Society of Cardiology (ESC). “The body has a 24-hour internal clock, called circadian rhythm, that helps regulate physical and mental functioning, while we cannot conclude causation from our study, the results suggest that early or late bedtimes may be more likely to disrupt the body clock, with adverse consequences for cardiovascular health,” said study author Dr David Plans of the University of Exeter, UK.

While numerous analyses have investigated the link between sleep duration and cardiovascular disease, the relationship between sleep timing and heart disease is underexplored. This study examined the association between objectively measured, rather than self-reported, sleep onset in a large sample of adults.

The study included 88,026 individuals in the UK Biobank recruited between 2006 and 2010. The average age was 61 years (range 43 to 79 years) and 58 per cent were women. Data on sleep onset and waking up time were collected over seven days using a wrist-worn accelerometer. Participants completed demographic, lifestyle, health, and physical assessments and questionnaires.

They were then followed up for a new diagnosis of cardiovascular disease, which was defined as a heart attack, heart failure, chronic ischaemic heart disease, stroke, and transient ischaemic attack.

During an average follow-up of 5.7 years, 3,172 participants (3.6 per cent) developed cardiovascular disease. Incidence was highest in those with sleep times at midnight or later and lowest in those with sleep onset from 10:00 to 10:59 pm.

The researchers analysed the association between sleep onset and cardiovascular events after adjusting for age, sex, sleep duration, sleep irregularity (defined as varied times of going to sleep and waking up), self-reported chronotype (early bird or night owl), smoking status, body mass index, diabetes, blood pressure, blood cholesterol, and socioeconomic status.

Compared to sleep onset from 10:00 to 10:59 pm, there was a 25 per cent higher risk of cardiovascular disease with sleep onset at midnight or later, a 12 per cent greater risk for 11:00 to 11:59 pm, and a 24 per cent raised risk for falling asleep before 10:00 pm.

In a further analysis by sex, the association with increased cardiovascular risk was stronger in women, with only sleep onset before 10:00 pm remaining significant for men.

Dr Plans said, “Our study indicates that the optimum time to go to sleep is at a specific point in the body’s 24-hour cycle and deviations may be detrimental to health. The riskiest time was after midnight, potentially because it may reduce the likelihood of seeing morning light, which resets the body clock.”

Dr Plans noted that the reasons for the observed stronger association between sleep onset and cardiovascular disease in women are unclear.

He said, “It may be that there is a sex difference in how the endocrine system responds to a disruption in circadian rhythm. Alternatively, the older age of study participants could be a confounding factor since women’s cardiovascular risk increases post-menopause – meaning there may be no difference in the strength of the association between women and men.”

“While the findings do not show causality, sleep timing has emerged as a potential cardiac risk factor – independent of other risk factors and sleep characteristics. If our findings are confirmed in other studies, sleep timing and basic sleep hygiene could be a low-cost public health target for lowering the risk of heart disease,” he concluded.

Eating higher total amounts of red meat, processed red meat and non-dairy animal fat increases the risk of stroke, while consuming more vegetable fat or polyunsaturated fat lowers it, according to a new study.

The findings of the research will be presented at the American Heart Association’s Scientific Sessions 2021. The meeting will be fully virtual, starting from November 13 and will go on till November 15, 2021. It is a premier global exchange of the latest scientific advancements, research and evidence-based clinical practice updates in cardiovascular science for health care professionals worldwide.

This study is the first to comprehensively analyse the impact on stroke risk from fat derived from vegetable, dairy and non-dairy animal sources.

“Our findings indicate the type of fat and different food sources of fat are more important than the total amount of dietary fat in the prevention of cardiovascular disease including stroke,” said Fenglei Wang, PhD, lead author of the study and a postdoctoral fellow in the department of nutrition at Harvard’s T.H. Chan School of Public Health in Boston.

The investigators analyzed 27 years of follow-up from 117,136 participants in the Nurses’ Health Study (1984-2016) and Health Professionals Follow-up Study (1986-2016), two of the largest studies to examine the risk factors for various chronic diseases.

Participants were age 50 years on average, 63 per cent were women, 97 per cent white, and all were free of heart disease and cancer at enrollment. At the beginning and every 4 years during the study, participants completed food frequency questionnaires that were used to calculate the amount, source and types of fat in their diets over the previous year.

Researchers calculated the cumulative average of the dietary data over time to reflect long-term dietary intake. The amount of fat intake was divided into 5 groups or quintiles.

In the study, total red meat included beef, pork or lamb as a main dish, in sandwiches or mixed dishes, and processed red meats. Processed red meats included bacon, sausage, bologna, hot dogs, salami and other processed meats.

The investigators found that during the study, 6,189 participants had strokes, including 2,967 ischemic strokes (caused by a clot cutting off blood flow to part of the brain) and 814 hemorrhagic strokes (caused by bleeding of vessels in the brain). Participants in the highest quintile of non-dairy animal fat intake were 16 per cent more likely to experience a stroke than those who ate the least (the lowest quintile).

“Based on our findings, we recommend for the general public to reduce consumption of red and processed meat, minimize fatty parts of unprocessed meat if consumed, and replace lard or tallow (beef fat) with non-tropical vegetable oils such as olive oil, corn or soybean oils in cooking in order to lower their stroke risk,” said Wang.

A new research has shown a 31 per cent increased risk for hospitalisation and mortality in patients with sleep-disordered breathing and sleep-related hypoxia.

The findings of the study were published in the journal ‘JAMA Network Open’. The research team, led by Reena Mehra, MD, analysed retrospective data from 5,400 Cleveland Clinic patients.

The findings showed that while patients with sleep-disordered breathing and sleep-related hypoxia do not have an increased risk of developing COVID-19, they have a worse clinical prognosis from the disease.

“As the COVID-19 pandemic continues and the disease remains highly variable from patient to patient, it is critical to improving our ability to predict who will have a more severe illness so that we can appropriately allocate resources,” said Dr Mehra, director of Sleep Disorder Research at Cleveland Clinic.

“This study improved our understanding of the association between sleep disorders and the risk for adverse COVID-19 outcomes. It suggests biomarkers of inflammation may mediate this relationship,” said Dr Mehra.

Researchers used Cleveland Clinic’s COVID-19 research registry, which includes data from nearly 360,000 patients tested for COVID-19 at Cleveland Clinic, of which 5,400 had an available sleep study record.

Sleep study findings and COVID-19 positivity were assessed along with disease severity. The team also accounted for co-morbidities such as obesity, heart and lung disease, cancer and smoking.

The findings set the stage for additional studies to identify whether early effective treatments such as PAP (positive airway pressure) or oxygen administration can improve COVID-19 outcomes.

“Our findings have significant implications as decreased hospitalisations and mortality could reduce the strain on healthcare systems,” said the first author of the study Cinthya Pena Orbea, MD, of Cleveland Clinic’s Sleep Disorders Center.

“If indeed sleep-related hypoxia translates to worse COVID-19 outcomes, risk stratification strategies should be implemented to prioritise the early allocation of COVID-19 therapy to this subgroup of patients,” Orbea added.

The study was funded by a Neuroscience Transformative Research Resource Development Award that was given to Dr Mehra.