Smoking

Overview

Cigarette smoke is heterogenous aerosol produced by incomplete combustion of tobacco leaf. On an average, smokers lose more than one day of life every week.

Clinical Correlations

Common disorders associated with smoking include:

Atherosclerotic cardiovascular disease
Cancer
COPD

The risk is dependent on duration, intensity and type of smoke exposure

Smoking and Cardiovascular Disease

Smoking, hypertension, and hypercholesterolaemia are three major risk factors for coronary heart disease (CHD). Presence of two out of the three risk factors may produces a 8-fold increase in CHD risk.
CHD death rates are 60 to 70% greater in male smokers than in non-smokers.
Sudden death is 2 to 4 times more common in young male smokers.
Women smokers also develop CHD especially when they take oral contraceptive pill also.
Those who continue to smoke after acute MI are most likely to die from CHD than those who quit smoking. Smokers have an increased perioperative mortality than non-smokers.
Similarly, cerebrovascular disease and stroke is also common in smokers. In women smokers, subarachnoid haemorrhage is more common; oral contraceptives increase the risk in them.
Peripheral vascular disease like thromboangiitis obliterans (TAO) and arteriosclerosis obliterans are common in smokers.
Hypertensives who smoke are at a greater risk of developing malignant hypertension and they die from complications of hypertension.

Smoking and Cancer

Smoking causes cancer of:

Oral Cavity
Larynx
Lungs
Oesophagus
Stomach
Pancreas
Urinary bladder
Kidney
Uterine cervix
Myelocytic Leukaemia

Smoking and Gastrointestinal Disorders

Gastric, and duodenal ulcer disease is more prevalent in smokers both in males and females. Smoking impairs ulcer healing, favours recurrence of ulcers, inhibits pancreatic HCO3 secretion and decreases the pressure of oesophageal and pyloric sphincters.

Smoking and Depression

Prevalence of smoking is increased in those who have a major depressive disorder.

Smoking and Body Weight

There is an inverse association between smoking and body weight. Weight gain occurs after cessation of smoking.

Smoking and Pregnancy

Smoking delays conception and smoking during pregnancy affects the foetus. Babies born to mothers who smoke have a weight of about 170 gm less than the babies born to non-smokers. This is due to impaired uteroplacental circulation.

Spontaneous abortion, foetal death, neonatal death and sudden infant death syndromes are also common. The long-term physical growth and intellectual development of the child is also affected.

Passive Smoking

Since side stream smoke is diluted in a large volume of air, smoke exposure from involuntary inhalation is less than that associated with smoking.

Passive smoking is one of the causes for lung cancer in non-smokers. Parental smoking is a cause for middle ear effusions, acute or chronic respiratory illness and asthma in children. Passive smoking may also cause coronary heart disease.