Since marijuana contains many of the same compounds as tobacco, it has the same adverse effects on the respiratory system when smoked as tobacco. These include chronic cough, respiratory infections, and bronchitis.18 In the longer term emphysema and lung cancer are also among its effects.21In fact, smoking marijuana is more harmful than tobacco for two reasons: first, because it contains more tar and carcinogens than tobacco, and secondly, because marijuana smokers tend to inhale more deeply and for a longer period of time as compared to tobacco smokers.
Marijuana use also has a variety of adverse, short- and long-term effects, especially on the cardiopulmonary system. Marijuana raises the heart rate by 20-100 percent shortly after smoking; this effect can last up to three hours. In one study, it was estimated that marijuana users had a 4.8-fold increase in the risk of heart attack in the first hour after smoking the drug. This elevated risk may be due to increased heart rate as well as the effects of marijuana on heart rhythms, causing palpitations and arrhythmias. This risk may be greater in older individuals or in those with cardiac vulnerabilities. Marijuana use has been found to increase blood pressure and heart rate and to decrease the oxygen-carrying capacity of the blood.39
Chronic smoking of marijuana and its active chemical THC has consistently been shown to increase the risk of developing testicular cancer, in particular a more aggressive form of the disease. One study compared 369 Seattle-area men aged 18-44 with testicular cancer, to 979 men in the same age bracket without the disease. The researchers found that current marijuana users were 1.7 times more likely to develop testicular cancer than nonusers, and that the younger the age of initiation (below 18) and the heavier the use, the greater the risk of developing testicular cancer.40,41,42
A similar study of 455 men in Los Angeles found that men with testicular germ cell tumors were twice as likely to have used marijuana as men without these tumors.43
THC can also cause endocrine disruption resulting in gynecomastia, decreased sperm count, and impotence.44
From the American College of Pediatricians
The American College of Pediatricians is a national medical association of licensed physicians and healthcare professionals who specialize in the care of infants, children, and adolescents. The mission of the College is to enable all children to reach their optimal physical and emotional health and well-being.
A PDF copy of this statement is available here: Marijuana Use: Detrimental to Youth
For more information, visit The Health Effects of Marijuana Use page on this website.