Medical Bulletin 07/ September/ 2024
Here are the top medical news for the day
Study Links Nighttime Light Exposure to Increase Alzheimer's Risk in Adults Under 65
In some places around the globe, the lights never go off. Streetlights, roadway lighting, and illuminated signs can deter crime, make roads safer, and enhance landscaping. Undisrupted light, however, comes with ecological, behavioural, and health consequences.
Now, researchers there have investigated correlations between outside nightly light pollution and Alzheimer's disease (AD).
“We show that in the US there is a positive association between Alzheimer's disease prevalence and exposure to light at night, particularly in those under the age of 65,” said first author of the Frontiers in Neuroscience study, Dr Robin Voigt-Zuwala, an associate professor at Rush University Medical Center. “Nightly light pollution a modifiable environmental factor may be an important risk factor for Alzheimer's disease.”
The researchers studied light pollution maps and incorporated medical data about variables known or believed to be risk factors for Alzheimer's disease in their analysis. They generated nighttime intensity data for every state and divided them into five groups, from lowest to highest nighttime light intensity.
Their results showed that for people aged 65 and older, Alzheimer's disease prevalence was more strongly correlated with nightly light pollution than some other disease factors, including alcohol abuse, chronic kidney disease, depression, and obesity. Other risk factors, like diabetes, high blood pressure, and stroke were more strongly associated with Alzheimer's disease than light pollution.
For people aged under 65, however, the researchers found that higher nighttime light intensity was associated with a greater Alzheimer's disease prevalence than any other risk factor examined in the study. This could suggest that younger people may be particularly sensitive to the effects of light exposure at night, the researchers said.
The researchers hope that their findings can help educate people about the potential risks of light at night. “Awareness of the association should empower people particularly those with risk factors for Alzheimer's disease to make easy lifestyle changes,” said Voigt-Zuwala. “Easy-to-implement changes include using blackout curtains or sleeping with eye masks. This is useful, especially for those living in areas with high light pollution.”
Reference: Voigt, R. M., Ouyang, B., & Keshavarzian, A. (2024). Outdoor nighttime light exposure (light pollution) is associated with Alzheimer’s disease. Frontiers in Neuroscience. https://doi.org/10.3389/fnins.2024.1378498
Research Finds Novel Mechanism That Predicts Severity Of Triple Negative Breast Cancer
Scientists at Huntsman Cancer Institute at the University of Utah (the U), the National Cancer Institute-designated cancer centre for the Mountain West, have made a significant breakthrough in predicting the prognosis of triple-negative breast cancer (TNBC), a particularly aggressive disease.
Their research, published in JCO Precision Oncology as part of the TOWARDS study, has led to the development of a new mechanism that accurately forecasts the aggressiveness of triple-negative breast cancer. This advancement could revolutionize the way doctors treat triple-negative breast cancer, allowing them to identify higher-risk patients and tailor precise treatments.
Currently, triple-negative breast cancer lacks reliable methods to predict recurrence after treatments like chemotherapy and surgery. Unlike other breast cancers, triple-negative breast cancer is challenging to treat because its tumour cells lack estrogen receptors, progesterone receptors, and high levels of HER2/neu protein, according to experts at the National Institutes of Health. This often results in a higher likelihood of relapse after treatment.
Researchers used a patient-derived xenograft (PDX) model, where biopsies of tumours from patients were implanted into mice to grow human tumours. Alana Welm, PhD, senior author of the study, senior director of basic science at Huntsman Cancer Institute, and professor of oncological sciences at the U, highlights the significance of this method noting that it allows for an early and accurate assessment of the cancer’s aggressiveness.
Cindy Matsen, MD, co-first author of the study, leader of the Breast and Gynecologic Disease Center at Huntsman Cancer Institute and associate professor in the Department of Surgery at the University of Utah, emphasizes the direct impact this research could have on patient care. She describes the study as highly relevant to addressing a major challenge in breast cancer treatment, with the potential of creating more personalized treatment plans for patients with recurrent triple-negative breast cancer.
Reference: Christos Vaklavas et al., TOWARDS Study: Patient-Derived Xenograft Engraftment Predicts Poor Survival in Patients With Newly Diagnosed Triple-Negative Breast Cancer. JCO Precis Oncol 8, e2300724(2024).DOI:10.1200/PO.23.00724
Early Pancreatic Cancer Staging Found Inaccurate 80% of the Time: Finds JAMA Study
Staging of patients with early pancreatic cancer is inaccurate as much as 80% of the time, according to a new study published in the peer-reviewed journal JAMA. The finding underscores the urgent need for advancements in diagnostic technology and staging, which could significantly alter early pancreatic cancer treatment and research.
In this study, investigators looked at data from more than 48,000 patients in the National Cancer Database. Based on preoperative imaging, all of the patients in the study had either stage 1 or stage 2 pancreatic cancer.
Following surgery to remove their tumours, more than 78% of stage 1 patients and more than 29% of stage 2 patients were upstaged generally to a stage that includes lymph node involvement.
“Our research reveals that staging essential for making treatment decisions and determining research eligibility is often inaccurate in early-stage pancreatic cancer,” said Srinivas Gaddam, MD, associate director of Pancreatic Biliary Research at Cedars-Sinai and senior author of the study. “As the field is racing toward earlier diagnosis, early staging will become increasingly important.”
Diagnosis and staging of pancreatic cancer are difficult for the same reason. The pancreas, a digestive organ, is located deep in the body and current imaging technology isn’t always able to detect smaller tumours or lymph node involvement, said Gaddam, who is also an associate professor of Medicine and runs the Pancreatic Cancer Screening and Early Detection Program at Cedars-Sinai.
Lymph nodes, clusters of small immune structures, are an important factor in cancer staging and a key difference between early-stage and later-stage pancreatic cancer.
“Patients who have lymph node involvement have a worse survival rate than those without lymph node involvement,” Gaddam said. “When imaging is unable to detect lymph node involvement, staging may not reflect the true extent of the disease. Our findings suggest that lymph node involvement is being missed in four out of every five patients during the staging process.”
The five-year survival rate for stage 1 pancreatic cancer is more than 83%, but that drops to just 3% for patients with stage 4 disease which is when most patients are currently diagnosed.
Reference: Perrotta G, Mohamed G, Larson BK, et al. Accuracy of Clinical Staging in Early-Stage Pancreatic Ductal Adenocarcinoma. JAMA. Published online September 05, 2024. doi:10.1001/jama.2024.16332
Levels of Selenium and Magnesium Impact Asthma Patients: Finds Scientific Reports
Scientists at the Chongqing Medical University, China, have conducted a study to investigate the association between blood levels of heavy metals and all-cause mortality among adult patients with asthma.
The study is published in the journal Scientific Reports.
Asthma is a respiratory disease caused by bronchospasm and airway inflammation. The most common symptoms are breathing difficulty, chest constriction, wheezing, coughing, and thick mucus production.
The prevalence of asthma is increasing steadily worldwide, partly because of increasing environmental exposure to allergens, air pollutants, and tobacco smoke. Currently, more than 350 individuals are living with asthma worldwide, and around 250,000 annual fatalities are directly linked to the condition.
Heavy metals, including lead, cadmium, mercury, and manganese, are ubiquitous in the environment and can enter the lungs and bloodstream through ingestion of food or water and inhalation of polluted air. Exposure to these heavy metals can trigger inflammation and oxidative stress, which in turn can cause lung damage and premature death.
Selenium is a micronutrient that plays a vital role in reducing oxidative stress and improving immune response. It has a multifactorial relationship with respiratory diseases, including asthma.
Existing evidence indicates that low blood levels of selenium increase the risk of developing asthma; however, both deficient and excessive levels of selenium can be harmful.
In this study, scientists have evaluated the associations between blood levels of heavy metals and all-cause mortality in adult asthma patients.
For the study, the scientists screened National Health and Nutrition Examination Survey (NHANES) data and identified 2,432 adult asthma patients for the study analysis. They obtained patient data on blood levels of certain heavy metals, including lead, cadmium, mercury, selenium, and manganese.
The study found that a higher blood selenium level is associated with a significantly lower all-cause mortality in asthma patients. In contrast, a significant positive association was observed between blood manganese level and all-cause mortality among participants. However, it is important to note that the study found a significant U-shaped relationship for both selenium and manganese, indicating that both very low and very high levels of these metals are associated with higher mortality.
Findings suggest that modifying the amount of selenium in the diet and managing exposure to manganese could potentially improve the prognosis for individuals with asthma.
Reference: Liao, J., Wen, J., Wei, C. et al. Association between blood heavy metal element and all-cause mortality in asthmatic adults: a cohort study. Sci Rep 14, 20457 (2024). https://doi.org/10.1038/s41598-024-70250-8
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