Since the 1950s smoking has been linked to an ever increasing list of illnesses, with the US National Cancer Institute’s website listing cancers of the lung, oesophagus, larynx, mouth, throat, kidney, bladder, liver, pancreas, stomach, cervix, colon, rectum, acute myeloid leukaemia, heart disease, stroke, aortic aneurysm, chronic obstructive pulmonary disease (COPD) (chronic bronchitis and emphysema), diabetes, osteoporosis, rheumatoid arthritis, age-related macular degeneration, cataracts, pneumonia, tuberculosis, and other airway infections. In addition, “smoking causes inflammation and impairs immune function”.
In addition ASH states
- Smoking is the primary cause of preventable illness and death. Every year smoking causes around 96,000 deaths in the UK.
- Smokers under the age of 40 have a five times greater risk of a heart attack than non-smokers
- Smoking causes around 80% of deaths from lung cancer, around 80% of deaths from bronchitis and emphysema, and about 14% of deaths from heart disease.
- More than one quarter of all cancer deaths can be attributed to smoking. These include cancer of the lung, mouth, lip, throat, bladder, kidney, pancreas, stomach, liver and cervix.
- About a half of all life-long smokers will die prematurely.
- On average, cigarette smokers die 10 years younger than non-smokers.
One important thing to note, however, is that there is no disease which is uniquely associated with smoking. While smoking can increase the risk of any particular disease non-smokers can and do succumb to exactly the same diseases.
The lag between the decline in male smoking prevalence and the incidence of lung cancer is normally ascribed to a number of important factors, the most relevant of which is perhaps the age at diagnosis.
As can be seen clearly, lung cancer is typically a disease of old age. Data from 2011-2013 show that of the 24,483 cases of lung cancer diagnosed on average each year in men in the UK, only 2% of cases were in men under 50 and 12% in men under 60. 61% of cases were diagnosed in men over 70 and more than one in four cases were in men over 80. The average age at diagnosis on a weighted basis was 72 and a half. Survival ratios for lung cancer are typically low albeit that they have risen over time. One year male survival rates are ~30%, but five year survival is less than 10% and 10 year survival less than 5%. This is reflected in the following chart which shows age at death for men in England & Wales in 2014.
The average age of death from lung cancer from these statistics was 73.8 years which compares with an average age of all deaths of 75.4 years, a difference of 19 months. Lung cancer accounted for 7% of all male deaths, and 7% of all male deaths over 65. Looking at the equivalent data for Scotland, the average age of death from lung cancer was 73 for men, compared with an average age of death of 73 and a half. Lung cancer accounted for 8% of all deaths.
It is interesting, in our view, that the average age of death from lung cancer should be quite so close to the average age of all male deaths, both in England & Wales and Scotland. It is certainly not clear from the data that, as per ASH’s much repeated statement, ”On average, cigarette smokers die 10 years younger than non-smokers”. We will return to this in due course.