Korean J Pediatr 2011;54(10):401-404 • http://dx.doi.org/10.3345/kjp.2011.54.10.401 403 because they are the adolescents’ primary role models. The attitudes of parents toward smoking, their perception of smoking, and affection between parents and their children are all crucial factors that affect adolescent smoking. Frequent disagreements with parents, divorce between parents, abuse by family members, incest, immature parents, and poor intrafamilial linkage all contribute to the risk of adolescent smoking. 2. Companionship If the frequency of smoking is high among friends or family members of a similar age, an individual is more likely to follow the same course. The risk is particularly high when a student is transferred from one school to another or joins a new circle of friends. The risk of long-term smoking increases when an adolescent can easily access cigarettes or has been exposed to cigarettes at a young age. 3. Personal characteristics and psychopathological pro­ blems Each adolescent has a different value system, attitude, surrounding environment, and personal literacy (toward study and society). Children who are antisocial, rebellious, isolated from school and society, or show poor family relationships or academic performance are highly likely to begin smoking. Some adolescents try to overcome depression or fear through smoking. In addition, the rate of smoking is higher in men than in women. 4. Psychosocial problems While it has decreased in recent years, offering someone a ci- garette has been regarded as etiquette in Korean society, and adole- scents may learn this custom. Additionally, young adolescents may smoke, thinking that smoking can make them appear more mature and adult-like. Female students have recently begun smoking more frequently than before out of resistance to gender-based discrimination. In addition, adolescents sometimes start smoking as a way to emulate television or mass media celebrities and sports stars. The impacts of smoking on the health of infants and adolescents The neonates of smoking parents suffer chronic hypoxia from the fetal stage, which causes growth and developmental disorders, resulting in low birth weight, small height, small head and bust circumference, and delayed development of the shoulders. In addi- tion, miscarriage and premature birth occur more frequently. Neo- nates and infants who are exposed to passive smoking, as a result of parental smoking, have an increased incidence of serious respiratory diseases, such as bronchitis and pneumonia. According to a survey, the risk of hospitalization for respiratory diseases, particularly asthma and stridor, is over 28% higher in infants with smoking mothers than in those with non-smoking mothers. Another survey reported that medical problems, such as asthma, chronic otitis media, and sudden infant death, were more common in children of smokers than in those of non-smokers. Adolescent smoking causes dysfunction of the peripheral airway. One study found that the forced expiratory volume in a second (FEV1) of smoking adolescents decreased significantly; specifically, their forced vital capacity (FVC) was approximately only a half that of non-smoking adolescents. According to a report by Berlin-Breman, the ratio of FEV1/FVC decreased with an increasing concentration of carbon monoxide on expiration, a method of checking smoking, in adolescent smokers. In addition, the study found that high-density lipoprotein-cholesterol decreased in adolescents who had been smoking for less than 2 years. Smoking is known to damage pulmonary functions through changing the airway and pulmonary parenchyma, which increases the risk of respiratory and systemic infection, as a result of structural changes and immunological responses of the respiratory system. Smo- king generates various substances that cause bronchial inflammation, fibrosis, and the increased permeability of airway mucous membrane; these substances also decrease the mucociliary clearance of airway mucous membrane, making it difficult to remove pathogens, thereby leading to infection. Smoking also affects respiratory immunity by decreasing blood immunoglobulin, weakening antigen-antibody reactions, inhibiting cytokine secretion by weakening the function of phagocytes, and decreasing the count of CD4+ lymphocytes. As a result, smoking increases bacterial infection and viral infection in the respiratory system. Overall, these reports suggest that adolescents who smoke may be exposed to various smoking-related diseases within a few years of starting smoking. Problems and psychosocial aspects of adolescent smoking Naturally, the younger a person begins smoking, the longer the period and the larger the quantity of smoking. In particular, people who start smoking younger than the age of 15 are 4 times more likely to develop lung cancer than those who start at the age of 25 or later. In the U.S., the rate of new smokers is around 3,000 a day or 1 million a year, and 80% of these are children or adolescents10). The American Academy of Pediatrics11) recently classified cigarettes as one of the most addictive drugs and argued for strict inhibition of