Health - men's brains shrink more rapidly with ageing

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One of the more unusual studies into ageing that has been published this month, has demonstrated that men experience a greater reduction in brain volume across more regions as they age than women do. The longitudinal study released in the Proceedings of the National Academy of Sciences examined 12,500 magnetic resonance imaging (MRI) scans taken from 4,726 people (with at least 2 scans per person taken on an average of 3 years apart). The study participants did not have Alzheimer's disease or any cognitive impairments and were control participants in 14 larger data sets.

The researchers compared the brain structures of individuals over time such as the thickness of grey matter and the size of the hippocampus (which is essential to memory). The results found a greater reduction in volume across more regions in the brains of men than for women.  As one example, the postcentral cortex region (responsible for processing sensations of touch, pain, temperature and the body's own movements and position) declined by  2.0% per year in men and only 1.2% in women over the same period. 

The results of the study, not surprisingly, led  researchers to conclude that men age faster than women and have a shorter life expectancy. This is hardly new information. A question that remains unanswered by this study is why women are twice as likely to be diagnosed with Alzheimer's disease than men given their brains age more slowly. 

For men, this study only assists with the impression that as they age, they become old codgers. 

Climate Change - Heatwaves lead to faster ageing

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The invisible effects of climate change via the increasing number of heat waves are more profound than many people may have imagined from trends over the past couple of decades. Heat waves in general are a well known health risk through the effects of dehydration, loss of body mass and organ stress. The evidence is now building that heat waves increase the ageing process itself.

A long-term study of 24,922 people in Taiwan, published in Nature Climate Change in August this year, has found that a moderate increase in cumulative heatwave exposure increases a person's biological age "...to an extent comparable to regular smoking or alcohol consumption. The more extreme-heat events that people were exposed to, the more their organs aged".

To reach this conclusion, the researchers analysed data from medical examinations between the years 2008 to 2022 during which time Taiwan experienced around 30 heatwaves. The definition of 'heatwave' applied was a period of elevated temperature over several days.  The results from several medical tests including assessments of liver, lung, kidney function, blood pressure and inflammation was used to calculate biological age. 

The results from the study found that the more extreme-heat events that people experienced the faster the ageing process that occured. For every extra 1.3°C exposure for a participant, around 0.023 to 0.031 years on average was added to their biological clock.  While the initial numbers may appear small, over time with accumulated effects and across populations, the impact on public health would be meaningful and costly. As increasing heat is a key effect from climate change, this latest research demonstrates the wide range of implications for life on this planet.