Smoking consumes almost six per cent of the world's total spend on healthcare and nearly two per cent of global GDP, a new research has found.

In 2012 the total cost amounted to $1,436 billion, with nearly 40 per cent of this sum borne by developing countries. The four BRIC countries — Brazil, Russia, India and China — accounted for 25 per cent of it, the findings showed.

"These findings highlight the urgent need for all countries to implement comprehensive tobacco control measures to address these economic costs," the researchers said.

The detrimental impact of smoking on national health systems and economies has been widely studied since the 1960s, but most of these studies have focused exclusively on high income countries, the researchers noted.

So Mark Goodchild from World Health Organization (WHO) and colleagues wanted to include low and middle income countries to come up with more accurate estimates of the total global cost. 

And so they included data from 152 countries representing 97 per cent of the world's smokers.

They used the 'cost of illness' approach, first devised in 1960. This divides the economic impact of an illness into direct costs, such as hospital admissions and treatment, and indirect costs representing the value of productivity lost to death and disability in current and future years, for a given year.

The direct and indirect costs are then added up to provide the overall societal cost, usually expressed as a percentage of annual gross domestic product (GDP).

The researchers used data from sources such as the WHO and the World Bank to uncover information on the proportion of ill health and death attributable to smoking, national employment rates, and GDP for each of the 152 countries, to inform their calculations.

These showed that in 2012, diseases caused by smoking accounted for 12 per cent (2.1 million) of all deaths among working age adults aged 30-69, according to the study published in the journal Tobacco Control.

This figure included 1.4 million adults who would have been in the workforce.

The number of working years lost because of smoking related ill health added up to 26.8 million, 18 million of which were lost to death with the remainder lost to disability.

In terms of health spend attributable to smoking, this totalled $422 billion, equivalent to nearly six per cent of the global total.

The researchers pointed out that their calculations did not include the health and economic harms caused by second hand smoke or smokeless forms of tobacco, and that their estimates of lost productivity applied only to those who were economically active.