Medical Bulletin 11/August/2023

Here are the top medical news of the day:

Hypothalamus is different in people who are overweight

Cambridge scientists have shown that the hypothalamus, a key region of the brain involved in controlling appetite, is different in the brains of people who are overweight and people with obesity when compared to people who are a healthy weight. The researchers say their findings add further evidence to the relevance of brain structure to weight and food consumption.

They used an algorithm developed using machine learning to analyse MRI brain scans taken from 1,351 young adults across a range of BMI scores, looking for differences in the hypothalamus when comparing individuals who are underweight, healthy weight, overweight and living with obesity.

Reference: Brown, SSG, et al. Hypothalamic volume is associated with body mass index. Neuroimage: Clinical; 8 Aug 2023; DOI: 10.1016/j.nicl.2023.103478

Short, intense sun-seeking trips can disturb skin’s microbiome

Skin, the largest organ of the human body, is home to a vast array of bacteria, fungi, and viruses – microorganisms that compose the skin microbiota. Among other things, these microbial populations, which are organized in complex community structures, protect against pathogens. Prolonged exposure to UVR is associated with damage to DNA in skin cells, inflammation, and premature skin aging, yet intentional sun-seeking behaviors remain common.

Due to a lack of studies focusing on how individual behavior influences UVR-associated microbiota shifts, and how this may relate to skin health, researchers in the UK have now examined the effects of sun-seeking behaviors on the skin microbiota composition of holidaymakers.

Reference: Behaviour and Sun Exposure in holidaymakers Alters Skin Microbiota Composition and Diversity, Frontiers in Aging; DOI 10.3389/fragi.2023.1217635

World’s largest study shows the more you walk, the lower is your mortality risk

The study, published in the European Journal of Preventive Cardiology found that walking at least 3967 steps a day started to reduce the risk of dying from any cause, and 2337 steps a day reduced the risk of dying from diseases of the heart and blood vessels (cardiovascular disease).

However, the new analysis of 226,889 people from 17 different studies around the world has shown that the more you walk, the greater the health benefits. The risk of dying from any cause or from cardiovascular disease decreases significantly with every 500 to 1000 extra steps you walk. An increase of 1000 steps a day was associated with a 15% reduction in the risk of dying from any cause, and an increase of 500 steps a day was associated with a 7% reduction in dying from cardiovascular disease.

The studies analysed by the researchers followed up with participants for an average of seven years. The average age was 64, and 49% of the participants were female.  

Reference: “The association between daily step count and all-cause and cardiovascular mortality: a meta-analysis”, by Maciej Banach et al. European Journal of Preventive Cardiology. doi:10.1093/eurjpc/zwad229