Cold wave kills 281 on average every winter

There are at least 281 "cold wave induced" deaths on average annually in Bangladesh, according to a recent study.

The month of January sees the highest number of such deaths, followed by December, says the study titled "Cold wave induced mortalities in Bangladesh: Spatiotemporal analysis of 20 years' data, 2000–2019".

There were 81 cold wave events in the 20 years and the study found a slightly increasing trend in cold wave frequency over the period.

"Cold wave mortality varied from district to district; northwestern districts were more prone to cold waves and reported a higher mortality rate," said the study published earlier this month in the "Natural Hazards Research" journal.

There is no formal database about cold wave-related mortality. The researchers developed a cold wave mortality dataset using content analysis of cold wave related news of four national daily newspapers from 2000 to 2019 and crosschecked it with other related reports.

The six researchers -- four from Dhaka University's Institute of Disaster Management and Vulnerability Studies, and two from  Faculty of Medicine and Health Sciences, University of Oviedo, Spain -- analysed the data to obtain the spatiotemporal trends and characteristics of cold wave mortality in Bangladesh.

"Our initial target was to do mortality mapping. We found that cold wave duration and frequency was increasing over the 20-year study period," Md Khalid Hasan, associate professor at Institute of Disaster Management and Vulnerability Studies, told The Daily Star yesterday.

He also said a total of 5,610 people died due to the cold wave during the study period. In terms of mortality, Rangpur division remains at the top, followed by Rajshahi.

Experts said it was tough to say how many people died due to cold-related ailments as autopsies were not done.

"From my experience, I can say that pollution is one of the key causes for such deaths as asthma patients and the elderly become vulnerable in winter," Prof Abul Bashar Mohammad Khurshid Alam, director general of Directorate General of Health Services, said yesterday.

He also said air pollution must be curbed to reduce cold-related deaths.

Pollution caused over 2.15 lakh premature deaths in Bangladesh in 2019, according to a study published in the medical journal The Lancet in 2022.

It found that poor air quality was the main contributor to such deaths, while water and lead pollution and occupational hazards were the other causes.

The study found that more children and adult males died due to cold waves than adult females in Bangladesh.

"We did not differentiate male and female when it came to children," said Khalid, the lead researcher of the study.

Mentioning that the northern and northwestern districts in Bangladesh were more vulnerable to cold waves, the study found that about 58 percent of cold wave spells and 58.5 percent of cold wave mortality occurred in January, followed by 22 percent in December.

The highest district-wise mortality rate was found in Kurigram -- 163.63 deaths per million people per year.

Khalid said the study findings would serve as a foundation for future research and policy development to establish cold wave management guidelines and reduce the risk of cold wave exposure among vulnerable people.

Renowned medicine specialist Professor Ahmedul Kabir said environmental pollution must be curbed to reduce cold wave induced deaths.

He stressed on finding more accurate information on cold-related deaths, which would help the government formulate policy in this regard.