Obesity in Childhood: Our New Epidemic
Linda Russell, MS, RD/LD, CSP
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Over the past 30 years there has been a rapid increase in childhood obesity in the United States. Comparisons of the second National Health Examination Survey (NHANESII) in 1980 and NHANES III in 1994 show that the prevalence of being overweight in childhood doubled.1 More recent data suggest that the prevalence of overweight children is 34% to 36% and obesity is 18% to 20%. Other studies have found that obesity prevalence is increasing approximately 47% to 73% faster among black and Hispanic children than among non-Hispanic white children.2 Body mass index (BMI) is calculated by dividing the weight (in kilograms) by the square of the height (in meters, [m2]). The BMI has been recommended by the Centers of Disease Control (CDC) to be an appropriate screening method for childhood obesity.2 Since body composition changes during childhood, it is important to plot the BMI by age on standardized growth charts. Children with a BMI greater than the 85 th percentile are considered overweight and should be monitored closely. A BMI above the 95th percentile has been recommended as a cutoff point for evaluation of obesity. Those individuals with large frames and a high percentage of muscle mass may not be overweight, but the BMI may indicate so. Skin fold measures using standardized calipers can help to accurately determine if a person is truly fat. Childhood obesity often persists into adulthood. Whitaker et al. found that more then 50% of obese children remained obese into adulthood.2 Obesity in parents significantly increases the likelihood that children will also be obese. With this increase of obesity in children comes many of the same complications that are seen in obese adults.2 Type 2 diabetes mellitus, the form of diabetes generally associated with obesity in adults, now accounts for as many as 45% of new cases of pediatric diabetes.3 Children with a BMI > 3.0 standard deviations above the mean should be screened with a fasting insulin level to detect possible hyperinsulinism. Acanthosis nigricans (AN) is a skin condition consisting of hyperpigmentation (darkened skin) and velvety skin thickening occurring on the neck and other skin folds, such as at the elbows. AN is associated with hyperinsulinism (high blood insulin levels) and obesity in adults. Nguyen et al. found higher insulin levels and lower insulin sensitivity in overweight children with AN compared to children without AN.3 However, when adjustments were made for body fat mass, measured by dual-energy x-ray absorptiometry, there was no significant difference in insulin levels and insulin sensitivity between the overweight children with AN compared to those without AN. The conclusion from this study was that body fat content correlates with hyperinsulinism but the presence of AN on physical examination is not an especially useful indicator of the presence of diabetes. Other health problems in children that are attributed to or exacerbated by excessive body adiposity include hypertension, dyslipidemia, slipped epiphyses, tibia vara (Blount's disease), polycystic ovary syndrome, gallstones, steatohepatitis (fatty liver), asthma, sleep apnea, and pseudotumor cerebri.2 Longitudinal studies of overweight children over a forty year period show twice the rate of cardiovascular disease and hypertension, and triple the rate of diabetes, compared with children of normal weight.2 In addition to the physiologic effects obesity, the psychological impact is significant. Six-year old children have described overweight people as lazy, lying, cheating, sloppy, dirty, and stupid. Without a doubt, obesity is detrimental to a child's self esteem. The causes of obesity in childhood are multifactorial. Certainly a decrease in physical activity is a major factor. Studies have shown that preschool children spend 60% of the time in sedentary activities and only 11% in vigorous active playtime. Data from the Muscatine Heart Study indicated that prepubertal children spend 30 minutes per day in aerobic activity, while pubertal and postpubertal children spend only 8 to 10 minutes per day engaged in aerobic activity. Sedentary activities such as television viewing, telephone talking, hand-held game playing, and computer activities contribute to excessive gains in body weight.2 Gortmaker at al. reported that children who watched the most television were more than 8 times more likely to become obese than those who watched 0 to 2 hours of TV per day. Eating patterns is the other factor contributing to this epidemic of childhood obesity. Jahns et al. evaluated snacking behavior in children and adolescents over the past two decades.4 Energy intake increased by 30% per day between 1977 and 1996. The frequency of snacks during the day, plus the total quantity of food, was found to contribute. Other shifts in dietary patterns over the years include increases in soft drink consumption, the frequency of "eating out" (meals out of the home), the size of portions when eating out ("super sizing"), and overall food availability. Between 1965 and 1996, non-diet soft drink consumption by adolescents increased almost 35% in males and 45% in females.5 The clinician is in a key role in the prevention of a child becoming overweight by providing anticipatory guidance on healthy food and beverage selections and exercise. For children who the clinician identifies as overweight/obese it is important to obtain food, beverage, and exercise habit information and to make appropriate recommendations. Working with parents of overweight children is a time intensive venture. A clinician is most effective by remaining non-judgmental on this issue because obesity can be an emotional subject for parents and children. Even the word "obese" is offensive to some parents and should be avoided. Parents need to learn to give their child emotional support in an attempt to build self-esteem. Psychological or psychiatric consultation should be considered for some children. It is important for a clinician to understand the eating and physical activity of the family as a whole. It is essential to take both a diet and activity history. Diet histories, however, are not always accurate. Bandini et al. showed that obese adolescents unreported 42% of actual caloric intake.6 There are many simple steps that the clinician can take to advise families about good nutritional choices. Some families simply need basic nutrition education and to learn the importance of bringing only nutritious foods into the home. Simple information can help, such as that flavored chips have just as many calories as plain chips, that fruit juice contains the same number of calories as a non-diet carbonated beverages, and that fruits and vegetables are good snack choices. Many families need to learn to "eat out" less often. Parents of overweight children can help their child by teaching the child to learn to set limits. It may help develop healthier eating habits and facilitate communication if families sit together for meals without the distraction of TV. Many families will benefit from a consultation with a registered dietitian or possibly a therapist, preferably one specialized in pediatrics. It is not recommended for children to be placed on strict or fad diets. Guidance should be given on healthy food choices and creative ways to increase and enjoy exercise. It is important to help parents to set realistic goals for appropriate weights and weight loss for their children. Under the guidance of Antoinette Lloyd, MD, the Childhood Obesity Coalition for Duval County has recently been formed as a part of the federal campaign Healthy People 2010. The focus of the Coalition will be the prevention of childhood obesity through various education strategies. References
Jacksonville Medicine / June/July, 2002What's New
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