A study of older adults in Australia and the U.S. indicates that cholesterol levels that fluctuate significantly from year to year without a change in medication may someday help to identify those with a higher risk of developing dementia. In a six-year study of almost 10,000 adults in their 70s, researchers found people with stable cholesterol levels had a significantly lower risk of developing dementia or showing cognitive decline compared to those with fluctuating cholesterol levels.

Severe temperature spikes may double or triple the risk of irregular heart rhythm in people with implanted defibrillators. An analysis of health data for more than 2,000 people with implantable cardioverter defibrillators (ICDs) found that temperatures reaching 100°F (38°C) were more likely to lead to atrial fibrillation events.