Lab notes: Dementia risks from the environment, the AMR whammy for poor countries, and more

Pollution and pesticides can cause dementia

Exposure to air pollution and pesticides and an excess of minerals in drinking water are some of the environmental factors that increase the risk of developing dementia. A new review of 60 studies on dementia conducted by scientists at the University of Edinburgh showed that a lack of vitamin D, which is normally produced by the body when it exposed to sunlight, can also contribute to the onset of dementia.

Dementia is known to be triggered by genetic factors like high blood pressure, smoking, diabetes, obesity, depression as well as by social factors like low educational. However, all these risk factors fail to explain about a third of all dementia cases. The researchers say that it is important to consider environmental risk factors, particularly since something might be done to remove these risks. The study was published in the journal BMC Geriatrics.

Dementia affects about 47 million people around the world and is a growing health risk with a longer-living, aging population. According to some projections number of people with dementia will increase to more than 131 million by 2050.

More antibiotic resistance in low-income countries

Poor sanitation systems, particularly leaky sewage systems and contamination pf surface and ground water, could be causing an explosion of antibiotic resistance in developing countries. New research has shown a strong association between national income levels and the prevalence of antimicrobial resistance, which indicates that resources available for proper sanitation are crucial to contain the problem.

The study from the Center for Disease Dynamics, Economics and Policy in Washington DC grouped 45 countries according to their gross national income per capita into high income, upper-middle income and lower-middle income categories and examined the prevalence of three resistant pathogens in each of these country groups. The results clearly showed a higher prevalence of resistance bacterial species in lower income countries.

The authors cite poor environmental sanitation, poor infection control practices and lack of stewardship programs as contributors to this sharp rise in antibiotic resistance in lower-income countries.

The paper published in the International Journal of Infectious Diseases highlights how this excessive burden of resistance is likely to have devastating consequences. “First, infections by resistant organisms are associated with increased mortality and health costs. Second, effective antibiotics against bacteria with AMR are more expensive and not affordable for a substantial number of people living in resource-limited settings. Third, increasing the use of effective antibiotics against bacteria with AMR will lead to 125 higher resistance to last-resort antibiotics,” the paper says.

That bedtime thirst

Scientists have discovered a natural process that acts as a pre-emptive strike against dehydration during sleep. Researchers from McGill University have found that the brain actually stimulates thirst in the hours before sleep. Although the research was conducted on mice, the team says that the discovery has implications for drug development for problems that people face adjusting to shift work and jet lag.

What was already known is that rodents show a surge in water intake during the last two hours before sleep. The new study revealed that this water-guzzling behavior is not motivated by physiological factors like dehydration. On further investigation, the team found that restricting the access to water during the surge period resulted in significant dehydration of mice towards the end of their sleep cycle, which led them to conclude that increase in water intake serves to keep the animal optimally hydrated during sleep.

The researchers also looked for the mechanism of the thirst response and found that the neuropeptide vasopressin stimulated thirst neurons leading to the surge in water drinking.