3.21 Health effects for young people who smoke

Last updated:July 2021

Suggested citation: Winnall, WR, Letcher, T, Greenhalgh, EM & Winstanley, MH. 3.21 Health effects for young people who smoke. In Greenhalgh, EM, Scollo, MM and Winstanley, MH [editors]. Tobacco in Australia: Facts and issues. Melbourne: Cancer Council Victoria; 2021. Available from https://www.tobaccoinaustralia.org.au/chapter-3-health-effects/3-21-health-effects-for-younger-smokers  

 

Most of the risk of dying prematurely due to smoking is reversed if people quit smoking before the age of 30.1 However smoking during childhood and adolescence is associated with a range of immediate health problems, as well as laying the foundation for the development of serious disease in adulthood.2

Tobacco use contributes substantially to the burden of disease in young people in Australia. For men aged 25–44 years, 3.4% of their burden of disease was attributed to tobacco use in 2015. Tobacco use was the 7th most common modifiable risk factor contributing to burden of disease for these men in the 2015 Australian Burden of Disease study. For women in this age group, tobacco use contributed to 2.8% of their burden of disease, as the 6th most common modifiable risk factor.3 In people aged 30–39 years, the bulk of the burden of disease caused by tobacco use falls into 3 categories: respiratory diseases, cardiovascular diseases and musculoskeletal diseases. For people aged 40-49 years, cancer also becomes an important contributor.4

Much of the research regarding the health effects of active smoking for young people comes from cross-sectional studies. These studies show that young people who smoke have a higher chance of numerous conditions such as cardiovascular diseases, asthma and dental health issues. Cross-sectional studies, however, do not provide strong evidence that smoking is a cause of these conditions. It’s possible that young people with poorer health are more likely to choose to smoke, or that they are more likely to be smokers for other reasons associated with their poorer health, such as lower socioeconomic status. Although cross-sectional studies are included in this section, emphasis is placed on studies using multivariate analysis, longitudinal studies and studies of biological mechanisms, where possible, which in combination strengthen the evidence of smoking as a cause of disease and poor general health in young people.

The health effects of secondhand smoke on young people are discussed in Chapter 4.

3.21.1 Early signs of addiction

There is contention about how best to characterise nicotine dependence in young people, with increasing recognition that it may be inappropriate to extend adult criteria to adolescent smokers. There are qualitative differences between adolescents and adults in their experiences of withdrawal; craving tends to be the predominant symptom that is experienced by young people during abstinence, while withdrawal symptoms are minimal.2 Nonetheless, nicotine addiction develops rapidly in young people, with adolescent smokers reporting some symptoms of dependence at even low levels of cigarette consumption.5 Many people who begin to smoke regularly find it difficult to quit.5 Factors influencing smoking behaviour in young people are discussed in Chapter 5 and nicotine addiction among adolescents is discussed in Section 6.13.

Adolescents with early signs of nicotine dependence are more likely to become smokers as early adults. A longitudinal study showed that adolescent smokers that developed nicotine dependence by the age of 15 were more likely to be smokers at the age of 25.6, 7 Research in Victoria examining smoking among a large cohort of teenagers over a 10-year period has found a greater likelihood of substance abuse (especially cannabis dependence) and psychiatric illness in continuing smokers8 (see also Section 7.12).

3.21.2 General health of young people who smoke

Young smokers, including school students, are more likely to report suffering an overall diminished level of health compared with non-smokers.9-11 Recurrent headache has been associated with current smoking (daily and occasional) in Norwegian students aged 13–18 years,12 while among US students (grades 6 to 10), daily and experimental smokers were more likely than never smokers to report recurrent subjective health complaints such as headache and backache.13 Among a cohort of young US Navy recruits (average age 19.7 years at baseline), cigarette smoking was a prospective predictor of hospitalisation. Data from more than 5,000 young healthy female recruits from entry into the Navy, and up to 7–8 years of service, indicated that daily smokers had higher rates of musculoskeletal conditions as well as higher rates of hospitalisation for any reason.14 Daily smokers were also hospitalised for a significantly longer compared with never smokers and other smokers (including experimental, occasional and former smokers).14

3.21.3 Lung function, respiratory symptoms and early signs of lung disease in young people who smoke

Lung development is altered by early tobacco use. Active smoking causes reduced lung function and impaired lung growth during childhood and adolescence, and the early onset of lung function decline during late adolescence and early adulthood.2, 15 Young smokers’ lungs stop growing earlier, they attain lower maximal lung function, they have a briefer plateau phase, and their lung function declines earlier. This reduced lung growth can increase the risk of chronic obstructive pulmonary disease (COPD) later in life. Early quitting may therefore be particularly beneficial, to potentially avoid these effects on growing lungs.2 

Active smoking causes respiratory symptoms including shortness of breath, coughing, phlegm production and wheezing in children and adolescents.15 Even occasional smoking (on at least 5 days in the prior 30 days) has been found to be associated with shortness of breath and fatigue following regular activity in 18–­24 year old college students,16 while regular smokers among this group were more likely than non-smokers to report having any cough or sore throat in the past 30 days.16 In a study of people from Egypt, Jordan, Morocco and Oman, smokers had almost twice the odds of respiratory symptoms compared to non-smokers.17 Young people who smoke are more likely to get bronchitis than non-smokers.18, 19 Symptoms of chronic bronchitis may develop during adolescence or young adulthood in some smokers.18, 20 The prevalence of self-reported bronchitis symptoms (chronic cough and sputum production) among a cohort of 18–21 year old Finnish males was significantly higher among daily smokers than occasional smokers.18

In smokers with apparently healthy lungs, there are early biological signs of immune deficiencies. Immune cells from teenage smokers’ lungs have alterations in inflammatory responses that are likely to increase their risk of infection compared to non-smokers.21

3.21.4 Asthma in young people who smoke

Active smoking is associated with an increased risk of developing asthma and for exacerbating existing asthma in adolescents.22 Smoking also causes wheezing severe enough to be diagnosed as asthma in children and adolescents.2 Surveys among young adolescent smokers (12–14 years) have found active smoking to be associated with asthma/wheezing and rhinitis,23, 24 particularly in girls.23 Smoking has also been associated with asthma-related wheezing symptoms in 15–16 year old adolescents.25

A large study in Brazil measured current and severe asthma in over 66,000 adolescents, aged 12 to 17 years. After adjusting for sociodemographic and lifestyle factors, the researchers found that regular smoking was associated with a 2.3-fold increase in the prevalence of current asthma and 2.4-fold increase in severe asthma.26 A longitudinal study tracked asthma and lung function in a population-based cohort from the Isle of Wight, UK, including people from 10 years to 26 years old.27 Smokers with asthma had worse lung function than non-smokers. Despite treatment, these differences persisted over time. These results show that lung function deficits for those with asthma start early in life for smokers and persist despite treatment for asthma.27

3.21.5 Cardiovascular disease in young people who smoke

Cigarette smoking during adolescence and young adulthood begins the damaging processes that lead to cardiovascular disease.2 Damage to the circulatory system becomes evident in young smokers, and may become clinically significant in early adulthood.9 There is evidence demonstrating that smoking during adolescence and young adulthood increases the development of atherosclerosis. By early middle age, the more rapid progression of atherosclerosis and the rapid decline of lung function mentioned above lead to higher rates of coronary heart disease and stroke. These diseases play a major role in the premature mortality of middle-aged and elderly smokers.2

A meta-analysis from 2019 showed that active smoking in childhood or adolescence is associated with subclinical vascular damage.28, 29 This analysis included data from 12 studies (5,279 people) measuring functional and structural markers of subclinical atherosclerosis that are strongly associated with the risk of future cardiovascular events. A smaller study showed that smoking in young adults was associated with a decline in cardiac function, after taking into account the effects of BMI and gender.30 A study assessing the influence of smoking on blood biochemistry in male Taiwanese university students (mean age 19.4 years) found young smokers had a significantly increased risk of several conditions associated with cardiovascular and haematological disorders, including high triglyceride levels, neutrophilia (a high percentage of neutrophils in the blood which is characteristic of infection) and hyperchromia (paler than normal red blood cells), compared with non-smokers.31 There is also evidence suggesting that even occasional smoking on a regular basis (<1 pack per week for at least 1 year) is associated with both acute and chronic impairment of arterial function (related to the development of atherosclerosis (hardening and narrowing of arteries) and future cardiovascular complications) in otherwise healthy young people (20–26 year olds).32 Similarly, a study on the effect of chronic smoking on arterial stiffness among young smokers (mean age 24.3 years) compared with non-smokers (mean age 20.2 years) found significantly higher arterial stiffness among smokers. Arterial stiffness is an important factor in the development of a range of pathophysiological processes including atherosclerosis, left ventricular hypertrophy (enlargement and thickening of the walls of the heart's main pumping chamber) and aneurysm.33 These results suggest that the negative effect of cigarette smoking on the vascular system may be apparent even in young smokers who have been smoking for less than 10 years.33 Cigarette smoking-related DNA methylation changes (a modification of DNA) in young people may be associated with changes in sub-clinical markers of cardiovascular health.34

The 2012 US Surgeon General’s report concluded that smoking in adolescence and young adulthood is a cause of early abdominal aortic atherosclerosis in young adults. This damage can lead to abdominal aortic aneurysm, a rupture of the aorta that is often fatal (see Section 3.1.4).

Smoking has been identified as one of the major risk factors for hospital admission for acute coronary syndrome and the more severe acute myocardial infarction (AMI, i.e. heart attack) among Middle Eastern,35 Chinese36 and Swedish37 populations, particularly among young patients (≤40 years old,35; 25–65 years old,37). A prospective study to evaluate the impact of smoking habits on long-term outcome in individuals who sustained AMI at the age of ≤35 years found that the most common risk factor at initial presentation was smoking.38 With up to 10 years’ of follow-up, over half of these people reported continuing to smoke. One-third of the participants experienced cardiac events during the follow-up period, including readmission for acute coronary syndrome, cardiac death or coronary revascularization because of clinical deterioration. Continuation of smoking was the most significant predictor of cardiac events during follow-up.38

Smoking is a risk factor for ST-segment elevation myocardial infarction (STEMI).36, 39, 40 This is a common and often deadly form of heart attack. A Danish study found that smoking was the most prevalent risk factor for STEMI in people aged 30–49. People who had STEMI in this age group were over 5 times more likely to be smokers compared to a reference group of those 70 years old and over with STEMI.39 In a similar study, data from the South Yorkshire population in England showed that smoking was associated with an 8-fold increased risk of STEMI in young smokers (under the age of 50), when compared to ex- and never smokers.40

Data from the National Health Interview Survey in the US show that young current smokers were at 14-fold higher risk of dying from coronary heart disease than non-smokers.41 This result was determined from data from over 120,000 people aged 18–44 years over the years 1997 to 2004. The 14-fold increased mortality estimate was adjusted to control for the effects of age, race, body mass index, history of hypertension and diabetes, and leisure time physical activity on mortality.41 While premenopausal women are typically relatively protected from heart disease compared with men and on average develop coronary heart disease 10 years later, smoking increases cardiovascular risk in young women and removes the protective effect of the premenopausal state; this is possibly caused by smoking disrupting the normal ovarian pattern of sympathetic nervous system activity.42

Tobacco use among young men, particularly cigarette smoking, is strongly associated with Buerger’s disease (thromboangiitis obliterans), a recurrent inflammatory, non-atherosclerotic vaso-occlusive disease.43 Caused by inflammation of the blood vessels, Buerger’s disease mostly affects men younger than 45 years with a current or recent history of tobacco use.44 Typically it involves progressive inflammation and clotting of blood vessels of the hands and feet, and the development of ulcers and gangrene of extremities as a result of vascular ischaemia.45 Commonly necessitating amputation, major amputations (of limbs rather than fingers/toes) are almost twice as likely in those who continue to smoke. Buerger’s disease has also been documented to involve scrotal and penile necrosis resulting in partial penectomy and scrotal debridement.43 The only apparent therapeutic measure to slow or prevent disease progression is smoking cessation.46

There is evidence for a strong dose–response relationship between cigarette smoking and ischemic stroke risk in young women.47, 48 A population-based case–control study of risk factors in over 1,000 US women aged 15–49 years found that the odds of ischemic stroke were 2.6-fold higher for current smokers compared to never smokers.The odds of ischemic stroke increased with increasing number of cigarettes smoked per day.47 No difference in stroke risk was observed between former smokers (those who had smoked more than 100 cigarettes in their lifetime, but had not smoked in the 30 days before their stroke) and never smokers.47 An 11-year prospective cohort study with over 45,000 Swedish women aged 30–50 years at the time of enrolment found that current smoking significantly increased the risk of stroke, particularly for ischemic stroke. There was a dose–response effect of current smoking on all strokes, with those smoking ≥10 cigarettes/day having a three-fold excess risk compared with never smokers. Similar risk patterns were observed using cumulative pack-years as an indicator of smoking exposure. Former smokers had a 60% increased risk for all strokes, which was of borderline statistical significance.48 The use of the oral contraceptive pill is a risk factor for stroke, and research among teenage girls (15­–17 year olds) who have suffered stroke suggests its use has a negative synergistic effect with smoking, with risk increasing with the number of cigarettes smoked.49

There is increasing evidence that smoking is also a risk factor for stroke in young men. A population-based case–control study of risk factors for ischemic stroke in men ages 15 to 49 years found evidence for a strong dose–response relationship between the number of cigarettes smoked daily and ischemic stroke among men under 50 years of age. In this study, men smoking 10 or fewer cigarettes per day have 1.46 increased odds of ischemic stroke, and those smoking 40+ per day had 5.66 increased odds compared to never smokers.50 A case-control study found of 155 people with cryptogenic stroke (the most common kind of ischaemic stroke in young people) found that these patients had 2.3-fold odds of being smokers compared to non-smokers. The mean age of these patients was 43 years old, which is relatively young for a first stroke.51

3.21.6 Metabolic syndrome in young people who smoke

Metabolic syndrome is a group of conditions/risk factors that increase the risk of diabetes and cardiovascular diseases. These five conditions, that often occur together, are obesity, high blood pressure (hypertension), high blood triglycerides, low levels of HDL cholesterol and insulin resistance.52 Smoking is associated with metabolic syndrome53-55 including young smokers,56, 57 even for young people smoking less than 30 cigarettes per week.58 In a study of over 5,000 people aged 10–18 years, active smoking was significantly associated with metabolic syndrome.59 Smokers are more likely than non-smokers to have four of the metabolic syndrome risk factors: hypertension, high blood triglycerides, low levels of HDL cholesterol and insulin resistance.60 The relationship between smoking and obesity is complex, and described in Section 3.29.

Smoking is a determinant of isolated systolic hypertension among young US adults (18–39 years); this is of concern because even small increases in systolic blood pressure in early adulthood increase risk of further cardiovascular disease (CVD) morbidity in later life.61 A study of over 500 university students in Jordan also found an association between smoking and increased systolic blood pressure.62 Studies of hypertension in young adults have found associations with structural changes in the heart including increases in left ventricular wall thickness, left ventricular mass and higher prevalence of left ventricular hypertrophy.61

A large US study among young people (10–22 years old) with diabetes found that current and past smokers were significantly more likely than non-smokers with the same condition to display cardiometabolic risk factors such as high triglyceride levels and to be physically inactive.63

3.21.7 Dental health problems in young people who smoke

Smoking is a major risk factor for poor periodontal health and oral cavity diseases64, 65; about half of the periodontitis seen in those aged under 30 is thought to be linked to smoking.66 Daily smoking and infrequent tooth brushing (less than twice a day) among 14–18 year old Finnish adolescents have been found to be strongly associated.67 There is also evidence to suggest that among young men (20–25 years old), even moderate smoking of 10 cigarettes per day induces variations of salivary lipid pattern.64 The regulation of salivary lipid levels is important in the maintenance of oral cavity health: elevated lipid levels are associated with an increase of caries incidence, plaque development, calculus formation and periodontal disease.64

3.21.8 Muscular skeletal problems in young people who smoke

It has long been known that tobacco use reduces bone mass and increases fracture risk in older people.68, 69 Smoking at a young age is also associated with unfavourable bone geometry and density, reduction in peak bone mass and increased fracture prevalence.70, 71 A cross-sectional population-based study among 677 healthy male Belgian siblings at the age of peak bone mass (aged 25–45 years) found that those who took up smoking at an early age (16 years old or younger) had lower areal bone mineral density (aBMD), lower cortical bone area at the tibia and lower trabecular and cortical bone density at the radius compared with current and never smokers.70 There were significant negative associations between number of pack-years smoked and lumbar spine, hip and total body aBMD, as well as total body bone mineral content. In addition, self-reported fractures were significantly more prevalent in early and current smokers.70 It has been suggested this may be caused by smoking disrupting the acquisition of peak bone mass during puberty, possibly due to an interaction with sex steroid action.70

Similarly, in a large population-based study of more than 1,000 young Swedish men (mean age 18.9 years), significantly lower aBMD of the total body, lumbar spine, femoral neck, and trochanter was found among current smokers (at least one cigarette per day) compared with non-smokers.71 The magnitude of observed differences was considerable, including a mean difference of 3.3% in the spine and 5% in the trochanter. Volumetric BMD (vBMD) and bone size were also measured: smokers had lower cortical thickness than non-smokers of both the radius and tibia. The authors suggest that the effects of smoking on bone mass may occur quite rapidly, because the mean duration of smoking in this study was 4.1 years.71

3.21.9 Fitness of young people who smoke

Young smokers tend to be less physically fit than their non-smoking peers, with fitness declining with increasing levels of tobacco consumption.9, 72 The cumulative effects of smoking from a young age on physical performance in midlife was assessed in a large British cohort study with data on smoking history from age 20 (median age at smoking initiation 16 years).73 This study found that at age 53, ever-smokers had significantly poorer overall physical performance, balance and chair rising than never smokers, with performance decreasing significantly for every 10 pack-years smoked.73

A study of a cohort of 18–21 year old Finnish men found that levels of aerobic fitness were significantly lower in regular smokers compared with non-smokers.18 A small study among a group of healthy young smokers (mean age 21.4 years) found that smoking was associated with resting and exercise tachycardia, demonstrating significant and acute negative effects on cardiac autonomic function due to smoking both at rest and during exercise. Results suggested that pre-exercise smoking of a single cigarette impaired physiological response to both peak and sub-maximal exercise; this may greatly increase vulnerability to myocardial electrical instability and therefore predispose to higher risk of cardiovascular events.74

An exercise-induced inflammatory response was found to be stronger in young smokers compared to non-smokers. Markers of inflammation in the blood were higher in smokers after 40 minutes of cycling compared to age- and fitness-matched non-smokers.75

3.21.10 Other health effects in young people who smoke

There is some evidence to suggest an association of smoking and a range of other health issues in young people. These include reduced taste sensitivity, sleep disorders, vocal dysfunction, altered brain development and cognitive function. The research in these areas is preliminary and there is a lack of studies that have addressed the question of causation. 

A study of 62 young men (mean age 24.9 years), showed a significant reduction in taste sensitivity in smokers. There were also more signs of atrophic papillary structures (degradation of the tongue papillary) in smokers compared with non-smokers.76

A case-control study of 109 young adult men found signs of laryngeal irritation and disturbed phonatory physiology in smokers compared to non-smokers.77 Smokers had a higher voice handicap index and a lower maximum phonation time. 

An association between current smoking and sleep disorders has been found in Chinese adolescents.78 A study of 29,000 Chinese adolescents aged 12–18 years found current smoking to be associated with increased snoring, difficulty breathing during sleep and difficulty maintaining sleep compared with never smokers.78 However, the relationship is likely to be complex, as problems sleeping could be leading to smoking, and smoking is also associated with use of substances such as caffeine that can affect sleep. A longitudinal study of the reciprocal relationship between smoking and sleep in young people found that smoking frequency was significantly associated with future sleep problems.79

Tobacco use during adolescence and young adulthood is associated with numerous changes to the structure and functioning of the brain. Resting state abnormalities within fronto-striatal circuits were found in young smokers. These abnormalities were associated with craving and cognitive control impairments.80 Abnormal topological organisation of brain functional networks were found in 30 young male smokers compared to non-smokers, matched for age, gender and education.81 A similar study found an increase in functional connectivity in numerous regions of the brains of young adult smokers. This functional connectivity correlated with increased pack-years, smoking duration, nicotine dependence, first smoking age and number of cigarettes per day.82 Some studies have shown cognitive defects in smokers compared to non-smokers, however longitudinal studies are necessary to establish whether smoking causes such defects.83

White matter refers to regions of the brain made up of the axons (extensions) of neurons, but not the main body of these cells. White matter plays a role in brain function and learning as messages are passed through these areas, connecting different regions of the brain.84 White matter development is ongoing through adolescence and young adulthood, and may be affected by nicotine.85 A systematic review of the effects of smoking on the white matter of young adult smokers found five studies reporting fractional anisotropy in numerous regions of the brain – indicating an increase in white-matter fibre integrity. This type of variation may be associated with impulsivity and risk-taking, however further studies are needed to determine whether tobacco is a cause or effect of changes in white matter fibre integrity.85 Since this review, further studies have also shown differences between the white matter regions of smokers and non-smokers.86-88


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