Cardiovascular Risk Factors in Youth

Family History

The NHLBI Expert Panel Guidelines recommend a detailed family history assessment be taken at the initial encounter and/or at 3 years of age, followed by repeat assessments at 9 to 11 years and 18 years. If there is a positive family history, the patient should be evaluated for other CVRFs. Furthermore, if a positive family history is present or the child has positive CVRFs, other family members should be evaluated (“reverse cascade screening”). Finally, the family history should be reviewed at each nonurgent health encounter.

A positive family history for premature CVD is defined as the presence of CVD (myocardial infarction, treated angina, percutaneous coronary catheter interventional procedure, or coronary artery bypass surgery), stroke, or sudden cardiac death in a parent or sibling, in males younger than 55 years old and females younger than 65 years old. As the parents and siblings of children and adolescents undergoing assessment are often quite young themselves, the Expert Panel expanded this definition to include premature CVD occurring in grandparents and aunts and uncles.

In longitudinal epidemiologic studies of CV risk, a family history of premature CVD is associated with increased risk of CVD in adulthood. In infants, a positive family history in grandparents is associated with relative coronary artery luminal narrowing at autopsy compared with infants without positive family histories. Noninvasive assessments have also demonstrated increased carotid intima media thickness (cIMT) and reduced endothelial function (brachial flow-mediated dilation [FMD]) in children and young adults with a strong history of premature CVD. Family history of CVD is associated with the elevation of CVRFs in the children. These findings suggest that family history is an important consideration in the cardiovascular risk assessment of children and adolescents. However, family history may be inaccurate and incomplete, owing to factors such as divorce, geographical separation, and other social circumstances.

Tobacco

Tobacco use among family members should be assessed at each well-child visit. Among its countless adverse effects, cigarette smoking is a potent CVRF, promoting atherosclerotic development even in young individuals. Several studies have also linked secondhand smoke exposure to CV risk in youth, and in-utero secondhand smoke exposure appears to have an obesogenic effect. In addition, exposure to secondhand smoke is a risk factor for future cigarette use. Fortunately, exposure to secondhand smoke and trends in cigarette use among youth have been decreasing in recent decades.

While trends in cigarette use have been declining, the use of electronic cigarettes is increasing in popularity among youth. Though most adults use these devices for smoking cessation, youth who experiment with them are typically smoking-naïve and are motivated by new, appealing features of electronic cigarettes. Therefore while further study is required to understand the safety, or otherwise, of these devices themselves, concern exists that electronic cigarette use may be a risk factor for future cigarette use in youth.

Given the impact of both cigarette smoking and exposure to secondhand smoke, interventions should target both parents and children/adolescents. It should be recognized, however, that public health measures, rather than individual counseling assessments, have been the most successful to prevent and limit tobacco use. This includes taxation of tobacco products, clean indoor air legislation, and advertising against tobacco products. Individualized interventions designed to reduce smoke exposure in children and tobacco initiation and reduction in adolescents have generally had mixed results. Despite this, given the importance of communicating the message of risk associated with tobacco use and the lack of harm associated with such interventions, routine identification and intervention of patients and families who smoke is imperative. Patients and families should be informed of the addictive and adverse effects of tobacco. The five “A questions” (Ask, Advise, Assess, Assist, and Arrange) can help physicians assess the readiness for quitting. From this, appropriate resources may be provided. While pharmacotherapies such as nicotine replacement have been shown to be effective in promoting smoking cessation in adults, studies in young smokers, to date, have yielded mixed results.

Nutrition and Diet

Dietary intake assessments should take place at each scheduled health visit. Consultation with a registered dietician may be necessary to ensure that adequate caloric intake is achieved within a healthy eating pattern. To optimize adoption of recommended changes, it is imperative to consider cultural practices and unique food preferences for each family.

In the first 6 months of life, human milk is the preferred source of complete nutrition for healthy term newborns, with continued breastfeeding recommended up to 12 months. Breastfeeding may potentially be protective against obesity, is associated with lower adulthood levels of total cholesterol (TC) and decreased cIMT, and is associated with a decreased risk of type 2 diabetes later in life. After the first 12 months, children should be transitioned to reduced-fat (2% to fat-free) milk.

Nutrient-dense food choices throughout childhood may have significant health benefits and decrease future risk of CVD. Higher fruit and vegetable intake has been associated with decreased adiposity, lower blood pressure, and reduced cholesterol levels. Conversely, sedentary children who frequently consume energy-dense and nutrient-deplete foods are at risk of developing overweight/obesity. Therefore added sugars and saturated and trans fats should be considered “discretionary” calories. The 2015–20 Dietary Guidelines for Americans (DGA) recommends consumption of a healthy eating pattern that accounts for all foods and beverages within an age-, sex- and activity-appropriate calorie level. This includes a variety of vegetables, fruits, grains, fat-free/low-fat dairy, a variety of protein-containing foods (seafood, lean meats and poultry, eggs, legumes, nuts, seeds, and soy proteins), and oils and limiting added sodium and sugar. Limiting total fat content less than 30% of daily calories has been shown to result in lower TC and low-density lipoprotein cholesterol (LDL-C). Furthermore, they recommend limiting saturated (<10% calories/day) and trans-fats, with the remaining 20% of fat intake coming from monounsaturated and polyunsaturated fats. Sugar-sweetened beverages and other foods with added sugar may be obesogenic and therefore should be avoided (<10% calories/day). With respect to natural, unsweetened, fruit juice the American Academy of Pediatrics recommends children aged 6 months to 6 years of age limit intake to 1 serving (4 to 6 ounces) per day and 2 servings per day for children 7 to 18 years old.

Physical Activity and Sedentary Behavior

Physical activity and screen time (TV, computer, cellphone) levels should be assessed at each well-child visit. Parents should be instructed that they must act as role models, creating an environment that promotes and models physical activity.

Physical inactivity is an independent risk factor for coronary artery disease. In recent decades, there has been a decrease in physical activity levels and increase in sedentary activities such that total screen time in children now ranges from 2.7 to 4.3 hours/day. These changes in physical activity patterns are associated with worsened lipid profiles, increases in systolic blood pressure, and increased levels of obesity, insulin resistance, and type 2 diabetes. Optimal cardiovascular risk profiles are seen in those who are consistently physically active.

The Expert Panel, in accordance with the 2008 Physical Activity Guidelines for Americans , recommends at least 1 hour of moderate to vigorous physical activity (comparable to walking briskly or jogging) per day with vigorous intense physical activity (comparable with running, playing soccer, or playing singles tennis) at least 3 days/week. The AAP recommends no screen time for children less than 18 months, high-quality programming only between 18 and 24 months supervised by a parent, and limiting screen time to 1 hour/day for children 2 to 5 years old, with appropriate parental limits set for screen time for children older than 6 years of age. Setting good physical activity patterns early in life is essential as childhood habits track fairly well into adolescence and adulthood. Furthermore, physical activity patterns (ideal or adverse) cluster with dietary choices, and smoking patterns.

Overweight and Obesity

Starting at age 2 years, body mass index (BMI, kg/m ² ) should be routinely calculated at all visits and compared to age- and sex-specific percentiles from the Centers for Disease Control and Prevention (CDC). A BMI between the 85th and less than 95th percentile is classified as overweight and greater than or equal to 95th percentile as obese. Although a recent study demonstrated a downward trend in the prevalence of obesity among 2- to 5-year-old children, there have been no overall changes in prevalence of obesity in youth between 2003 and 2012, with obesity rates in children 2 to 19 years old remaining at approximately 17%. Children at risk for developing obesity include those who are currently overweight, have a positive family history of obesity in one or both of the parents, experience more rapid increases in weight than height, have excessive increases in weight during adolescence, and who have increased sedentary time. Due to the association of obesity with elevations in other CVRFs, the presence of obesity should prompt evaluation for CVRF clustering, including assessments of blood pressure, lipids, insulin resistance and risk for type 2 diabetes, liver function abnormalities, left ventricular hypertrophy, and sleep apnea. Addressing the childhood obesity epidemic is imperative as obesity is associated with atherosclerotic burden at autopsy, tracks strongly into adulthood, and its presence in childhood is significantly associated with coronary heart disease events in adulthood. Improvements in weight status are associated with improvements in various modifiable CVRFs, including blood pressure, TC, LDL-C, triglycerides (TG), and insulin resistance. Overweight and obesity are also associated with subclinical markers of vascular dysfunction, and exercise and weight loss are associated with improvements in these measures.

In addition to guidelines for healthy diet and exercise for all children, practitioners should be aware of additional recommendations for treatment of overweight and obesity (see below). While trials of community-based programs have yielded mixed results, comprehensive multidisciplinary lifestyle weight-loss programs have resulted in greater success in children older than 6 years. Medications such as orlistat and metformin may be prescribed for obese children and adolescents who have seen no improvements in obesity despite compliance with a dedicated obesity program. The Expert Panel recommendations for obesity management are as follows :

• Ages 2 to 5 years old: For overweight children, parents should be counseled with a focus on an energy-balanced diet and a reinforcement of physical activity recommendations. If no improvements are noted after 6 months, further counseling with a registered dietician is warranted. Obese children should undergo assessment of comorbidities (hypertension, insulin resistance, and dyslipidemia) and family-based weight-gain prevention initiated with counseling from a registered dietician and a prescription for moderate-to-vigorous physical activity and limited screen time. Follow-up should be arranged for 3 months.

• Ages 6 to 11 years old: In this age range, recommendations for overweight and obese children are the same as for younger children (above) with more aggressive dietary management and an emphasis on negative-energy balance if obese. If there are no improvements in BMI percentile, referral to a comprehensive multidisciplinary lifestyle weight-loss program should be made. Children with comorbidities at the initial assessment, a BMI greater than 97th percentile, or if with progressive rise in BMI despite therapy, should be promptly referred to a more intensive, comprehensive multidisciplinary lifestyle weight-loss program rather than an office-based plan.

• Ages 12 to 21 years old: For overweight and obese adolescents without comorbidities, an office-based strategy including counseling from a dietician regarding balancing energy intake and physical activity is the initial approach. If BMI does not improve in the obese patient, referral to a comprehensive multidisciplinary lifestyle weight-loss program should be made. For obese adolescents with comorbidities, or for those with a BMI greater than 35 kg/m ² , immediate referral should be made to a comprehensive multidisciplinary lifestyle weight-loss program. If there are no improvements despite compliance with such a program for 6 to 12 months, orlistat may be considered under the care of an experienced clinician. If the BMI remains far above 35 kg/m ² with comorbidities despite lifestyle therapy for over 1 year, referral to a center with experience in pediatric bariatric surgery may be considered.