Sydney, April 22 -- Urban heat islands, where city temperatures are higher than surrounding rural areas, are double-edged swords for residents, a new study said on Tuesday.

Urban heat islands are often linked to increased heat-related deaths. However, they may also help reduce cold-related deaths, particularly in colder cities, according to the Queensland University of Technology (QUT), which is part of the research.

Researchers from China's Nanjing University analysed data from over 3,000 cities worldwide and found that in 2018, the decrease in cold-related deaths due to urban heat islands was 4.4 times greater than the rise in heat-related fatalities, said the study published in Nature Climate Change.

In high-latitude cities like Mosco...