"Alcohol and tobacco are by far the biggest threat to human health around the world, while illegal drug harms 'don't even come close'," The Independent reports.
The news site writes about a recent report that provides the most up-to-date (2015) information about the global use of alcohol, tobacco and illegal drugs.
It looked at how common use of these substances was, how many people were dependent on them, and the public health harm they caused.
Across the countries, nearly 20% of adults reported drinking heavily in the last month. Around 15% of adults smoked daily. About 4% had used cannabis and less than 1% reported using opioids, amphetamines or cocaine in the past year.
Out of every 100,000 people around the world, 111 are estimated to die from tobacco-related causes, 33 from alcohol-related causes, and 7 from illegal drug use.
Globally, the amount of ill health and number of deaths associated with tobacco and alcohol use is higher than for illegal drug use.
Indeed, a case could be made that if tobacco and alcohol had only been discovered a few years ago, both may now have been added to the list of Class A illegal drugs.
These finding should not be wrongly interpreted as meaning that illegal drugs are any "safer".
Many drugs are known to carry serious risks, including long-term risks that are still not clearly understood – for example, the effect cannabis may have on mental health.
This report was written by researchers from institutes in Australia, including the University of New South Wales, the University of Tasmania and the University of Queensland. Researchers at a number of institutes in Europe and North America also contributed.
The research was supported by a number of funding sources, including the Australian National Health and Medical Research Council, the Australian Government, the PLuS Alliance (a joint project organised by 3 leading universities), and the Bill and Melinda Gates foundation.
It was published in the peer-reviewed journal Addiction.
Media headlines focused on the numbers of people around the world who experienced ill health or died as a result of tobacco or alcohol use – a much greater number than deaths or ill health caused by illegal drugs.
But this is not surprising considering that the use of illegal drugs is rarer in the population as a whole compared with smoking and alcohol.
The Mail Online correctly noted that the researchers have called for more reliable data collection around the world to address the current variations in data quality and availability.
For example, they struggled to find much reliable information about the extent of illegal drug use in many parts of the developing world.
This review of online international data sources aimed to find recent information about the use of tobacco, alcohol and illegal drugs around the world.
The researchers were interested in how much ill health was associated with these substances, and how many deaths could be related to their use.
But these are only estimates, and the statistical approaches used to form these estimates may have varied between different countries.
The data used came from a number of sources, including the World Health Organization, the United Nations Office on Drugs and Crime, and the Institute for Health Metrics and Evaluation's Global Burden of Disease study.
The researchers specifically looked for information to answer the following questions:
A standard way of reporting how much ill health is caused by a risk factor is the disability-adjusted life year (DALY).
This gives an estimate of how many years of life are lost as a result of this exposure, either from death or ill health.
Many of the sources the researchers found covered the period up to 2015, which was the most recent information available.
On average, 15.2% of adults around the world smoked tobacco daily in any given 30-day period. There was a high burden of ill health around the world associated with tobacco use (170.9 million DALYs). Tobacco was estimated to account for 110.7 deaths per 100,000 people.
Around the world, about 1 in 5 adults were estimated to drink heavily in any given 30-day period. The burden of ill health for alcohol was less than for tobacco, but still substantial: 85.0 million DALYs. Alcohol-related illness was estimated to cause 33.0 deaths per 100,000 people worldwide.
It was estimated that 3.8% of people around the world used cannabis and less than 1% used opioids, amphetamines or cocaine during the past year. The associated burden of ill health was 27.8 million DALYs. Illegal drugs contributed to 6.9 deaths per 100,000 people worldwide.
Eastern Europe had the highest rates of harmful alcohol and illegal drug use, and high rates of drinking were reported across all European regions. The lowest rates of alcohol consumption and heavy drinking were in north Africa and the Middle East.
The highest rates of tobacco-related deaths and ill health occurred in Oceania. Daily smoking was also very common in Europe. The lowest rates of smoking occurred in western sub-Saharan Africa.
High rates of cannabis, opioid and cocaine dependence were found in the US and Canada, while the highest rates of amphetamine dependence were found in Australia.
The researchers do not appear to have taken a systematic approach to identifying data, which means they may have missed some relevant information.
Their search was limited to online sources, so if a country had only published paper reports of its data, these would have been missed.
But the sources the researchers did find included reports from many large global health organisations that are likely to be reliable and to have captured the best available data.
There may be limited data collected from low- and middle-income countries, which means this report may not give a completely comprehensive global picture.
While death certificates and medical records can give the cause of death and disability, it's difficult to identify every factor contributing to that outcome.
This means figures on the number of deaths or years of life lived with disability due to that exposure can only ever be estimates.
It's also worth considering the wider negative implications of these substances, as studies often focus on the health consequences.
This means there might be less known about the social and economic effects, such as how someone's working life might be affected by difficulties with alcohol or illegal drugs.
This study gives us an interesting insight into how the use of alcohol, tobacco and illegal drugs differs around the world.
The potential harms tobacco and alcohol pose to our health are well established. Other illegal substances are known to cause potentially serious short- and long-term harm.