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February 16th, 2015:

Smoking is even MORE dangerous than we thought: Scientists link the habit to five extra diseases, bringing the total to 26

  • New study links smoking to 26 diseases – five more than thought in past
  • Link between cigarettes and lung disease, artery disease, heart attacks, stroke and some cancers is well documented
  • But scientists identified smokers are at double the risk of kidney failure, hypertensive heart disease, infections and extra respiratory problems
  • Also six times more likely to suffer rare condition caused by poor blood flow to the intestines
  • Estimated smoking kills 60,000 more Americans than thought each year
  • If five illnesses are included in smoking death toll, global figure could increase by hundreds of thousands, scientist’s findings suggest

Five diseases and health conditions not previously linked to smoking are now thought to be caused by the habit, scientists claim.

The link between cigarettes and lung disease, some cancers, artery disease, heart attacks and stroke is well documented.

But scientists at the Washington University School of Medicine have identified smoking is also linked to significantly increased risks of infection, kidney disease, intestinal disease caused by inadequate blood flow, and heart and lung illnesses not previously attributed to tobacco.

They studied health data from almost one million people, following them for 10 years.

Their findings suggest the number of people dying from smoking each year, across the world, is significantly underestimated.

In the US, health officials estimate smoking kills around 480,000 people each year.

Research has already established 21 diseases caused by smoking, including 12 types of cancer, six categories of cardiovascular disease, diabetes, chronic obstructive pulmonary disease [COPD], and pneumonia including influenza.

In the UK that figure is around 100,000, while the World Health Organisation estimate the global figure stands at six million, when taking into account second-hand smoke.

However, the team of scientists at Washington University believe those figures could be considerably higher, when taking into account deaths from the five additional health problems, they now believe are closely linked to smoking.

Dr Eric Jacobs, co-author of the study, estimates smoking could be killing around 60,000 extra Americans each year – around 13 per cent of the 480,000 deaths currently attributed to the habit each year.

If applied to the world wide figure, their theory suggests an extra 780,000 across the world could be dying from the affects of smoking each year.

Dr Jacobs, said: ‘The number of additional deaths potentially linked to cigarette smoking is substantial.

‘In our study, many excess deaths among smokers were from disease categories that are not currently established as caused by smoking, and we believe there is strong evidence that many of these deaths may have been caused by smoking.

‘If the same is true nationwide, then cigarette smoking may be killing about 60,000 more Americans each year than previously estimated, a number greater than the total number who die each year of influenza or liver disease.’

Those taking part in the study were men and women, all aged 55 or older .

Over the course of the decade-long study, more than 180,000 of the participants died.

Researchers found current smokers, as predicted, had death rates almost three times higher than those who had never smoked.

Their findings show the majority of excess deaths in smokers were due to diseases that are established as being caused by smoking, including 12 types of cancer, coronary heart disease, stroke, diabetes and chronic obstructive pulmonary disease (COPD).

But they also found around 17 per cent of the excess deaths in smokers were due to diseases that have not yet officially been linked to smoking, by the US surgeon general.

It means these deaths would not be counted in estimates of the death toll from smoking.

The scientists noted, in particular, that smoking was found to at least double a person’s risk of death from several causes, including renal failure, intestinal ischemia, hypertensive heart disease, infections and various respiratory diseases, other than COPD.

Smokers were also six times more likely to die from a rare illness caused by insufficient blood flow to the intestines.

The risk of death from each of these diseases was found to decline after a person quit the habit.

The study authors note there is strong evidence that smoking is a cause of death from these five diseases, even though they are not currently included in estimates of deaths caused by smoking.

Smoking was also linked with smaller increases in risk of death from other causes not formally established as caused by smoking, including breast cancer, prostate cancer, and cancers of unknown site.

The authors conclude that a substantial portion of excess mortality among smokers may be due to diseases not formally established as caused by smoking.

They add, that if supported by future research, some of the diseases should be included in future estimates of the death toll from smoking.


Past studies have already established a link between smoking and 21 different diseases, as recognised by the US surgeon general.

They are:

  • 12 types of cancer
  • six categories of cardiovascular disease, including coronary heart disease and stroke
  • diabetes
  • chronic obstructive pulmonary disease (COPD)
  • pneumonia including influenza

This new study, funded by the American Cancer Society, found strong links between five additional health problems and cigarettes.

They are:

  • kidney disease – renal failure
  • intestinal ischemia
  • hypertensive heart disease
  • infections
  • various respiratory diseases, other than COPD

Dr Brian Carter, an epidemiologist at the American Cancer Society, which funded the research, told the New York Times: ‘The smoking epidemic is still ongoing, and there is a need to evaluate how smoking is hurting us as a society, to support clinicians and policy making in public health.’

The study was an observational one, assessing people’s habits and noted statistical correlations between their behaviour and their health.

Correlation does not prove a cause-and-effect relationship.

As a result these studies are not deemed as strong as experiments where volunteers are given random treatments, with placebo groups included for comparison.

People cannot ethically be instructed to smoke for a study, so much of the data relating to cigarette’s effects on people has to come from observational studies, such as this.

The study was published in the New England Journal of Medicine.