Cigarette smoking is the most important source of preventable deaths and illnesses and early deaths worldwide, according to the American Lung Association.

In general people become smokers beginning with the teenage years. And many of the deaths caused by smoking are a result of choices made by them. Every day, about 4,000 children between the ages of 12 and 17 smoke their first cigarette, and half of them will ultimately die because of their habit.

Smoking at a young age produces immediate health problems including cough and phlegm production, respiratory illness, decreased physical fitness, an unfavorable lipid profile and lung damage. And also in adulthood the health problems linked to smoking don't disappear. In fact, the problems often get worse than better.

Research showed that smoking during youth often serves as a "gateway drug" to use of illegal drugs.

Scientists have identified the genetics behind both an increased lung cancer and an increased heart attack risk in smokers. But one recent study examined the genetics of smokers who were successful and smokers who were unsuccessful at quitting their habit.

They found that a person's ability to quit smoking is highly influenced by genetic variants, variants that coincide with a person's vulnerability to dependence on other addictive substances. Experts reported also that the gene variants responsible for a person's level of addiction are possible targets for anti-smoking therapies.

Researchers showed that smoking as a teenager is associated with greater consumption of cigarettes as an adult and a stronger addiction to smoking in adulthood.

According to a new study conducted at University of Utah, was shown that those who begin smoking at or before age 16 are likely to suffer a severe dependence on nicotine as adults.

Scientists added in a study that one of the next steps is to identify those who have the risky genetic factor and create targeted prevention and treatment plans for them. This maybe will combat a portion of the smoking epidemic and perhaps lower the national burden of smoking-related illness.