Obese Children Who Are Referred to the Pediatric Endocrinologist: Characteristics and Outcome
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《小儿科》
Division of Endocrinology/Diabetes, Women's and Children's Hospital of Buffalo, Buffalo, New York
ABSTRACT
Objective. The objective of this study was to characterize a population of obese children who were referred to a pediatric endocrinology clinic and to analyze the outcome of the referral.
Methods. Children who were referred for obesity and seen at least twice between January 1984 and July 2003 were included in this retrospective study. Demographic, clinical, and, when available, laboratory (fasting glucose and insulin, random cholesterol, and liver function tests) and bone age data were abstracted from the medical record at the first and last endocrine evaluations. Self-reported parental height, weight, and family history of diabetes were also entered in the database. Records from the pediatrician were used to identify the age of onset of obesity.
Results. The database included 587 children (mean age at referral: 9.5 years) with a preponderance of non-Hispanic white children (75.6%) and female gender (57.6%). Growth records in 251 children indicated that 80.6% of the children had become obese before the age of 6 years and were referred 4.3 ± 2.9 years after having become obese. At follow-up, 38% of the children exhibited a decreased percentage of overweight compared with the baseline visit, but only 5 children had an age- and gender-specific BMI below the 95th percentile. Cholesterol and fasting insulin were elevated in 174 of 311 and 72 of 94 children, respectively. Bone age radiographic records for 157 patients showed significant advancement in 46%. Half of the mothers and 57.7% of fathers were obese, and type 2 diabetes was self-reported in 11.4% parents.
Conclusions. In the majority of this predominantly non-Hispanic white referred sample of obese children, overweight started in the preschool years. The referral to the endocrinologist, occurring after a prolonged interval from the obesity onset, was ineffective in treating obesity. Hyperinsulinemia and hypercholesterolemia are often present also at a young age. These obesity comorbidities in association with high prevalence of parental obesity and type 2 diabetes expose these youths to high risk for developing type 2 diabetes and coronary heart disease. Our data underscore the need for early family-based behavioral-lifestyle intervention programs to be made available to pediatricians, enabling them to target the "at risk for overweight" preschool children and their likely overweight parents.
Key Words: pediatric obesity onset outcome hyperinsulinemia
The prevalence of obesity has increased dramatically in recent years across all pediatric ages.1–3 Obese children are at risk for becoming obese adults,4,5 and many known comorbidities observed in obese adults are now observed more frequently in youths, type 2 diabetes representing a dramatic example.6–11 The psychological impact of obesity is just as devastating as the medical implication, with the overweight children having a 5-fold increased risk for low health-related quality of life, a risk similar to what is observed in children who are affected by cancer.12 Finally, the economic burden of childhood obesity has also increased 3-fold in the past 20 years, reaching $127 million per year.13
Family-based behavioral modification treatments have been the only therapeutic modality to demonstrate long-term success in the treatment of pediatric obesity.14,15 However, the expertise needed, manpower, and overall cost have prevented thus far the translation of these interventions to the population at large. Pediatricians who attempt to educate the child and the family are often unsuccessful and refer the child to the nutritionist and/or pediatric endocrinologist. The criteria for referring the overweight child to the pediatric endocrinologist and the referral's outcome are unclear. The aim of our study was to characterize a population of obese children who were referred to a pediatric endocrinology clinic and to analyze the outcome of the referral.
METHODS
Using a database pertinent to children who were referred to a pediatric endocrine clinic located in a tertiary regional hospital, we identified all children who had a primary or a secondary International Classification of Diseases code of "exogenous obesity" between January 1984 and July 2003. We excluded children with diabetes, untreated thyroid disorder, Prader-Willi syndrome, and other endocrine disorders or syndromes associated with obesity. The patients were included in the database only after confirming the International Classification of Diseases code by calculating BMI as outlined below. During the visits, the child and the accompanying caregiver received counseling on lifestyle changes and verbal and written guidelines regarding healthy nutritional habits and physical activity. Children and families who had not already seen a nutritionist were advised to seek a consultation and provided with the names and numbers of dietitians who are experienced in pediatric care. The families were also made aware that counseling was available from 2 psychoendocrinologists who often met with families in the clinic.
Demographic data, height, weight, heart rate, blood pressure, and, when available, laboratory and bone age data were abstracted from the pediatric endocrine medical record at the first and last endocrine evaluations. The laboratory data included fasting glucose and insulin, random cholesterol, and liver function tests. Using information reported by the caregiver who accompanied the child to the endocrine evaluation, parents' height; weight; and family history of diabetes, hypertension, and heart disease were also entered in the database.
Growth charts sent by the referring primary care physicians were used to determine age at the onset of obesity. Only growth charts that had consistent yearly measurements and were performed by the same pediatric office were used, and the timing of onset of obesity was never extrapolated, rather it was obtained by the first height/weight measurement that yielded a BMI measurement above the 95th percentile. In children who were aged 2 years or older, obesity and overweight onset were defined by the age at which BMI was 95th or 85th percentile, respectively for age and gender. BMI was calculated as weight in kilograms divided by height in meters squared (kg/m2). When growth data revealed that a child's BMI was already >95th percentile at 2 years of age, the onset of obesity was defined by the age at which the child as an infant first presented length:weight ratio >95th percentile, in keeping with recommendations from the Special Supplemental Nutrition Program for Women, Infants, and Children.16,17 The child's percentage overweight at the first endocrine clinic visit was compared with the percentage overweight at the most recent follow-up. Percentage overweight was calculated by comparing the child's actual BMI with that child's age and gender BMI at the 50th percentile according to the following formula: present BMI/BMI at the 50th %ile x 100. Data were expressed as mean ± SD and analyzed in SPSS (version 8.1) using Mann-Whitney U, Wilcoxon matched pairs signed ranks, and Kruskal Wallis.
RESULTS
The database includes 587 medical records and is composed of 75.6% non-Hispanic white children, 19.4% non-Hispanic black children, 3.4% Hispanic children, and 1.5% children belonging to other races. The mean age at the first endocrine clinic visit is similar in non-Hispanic white (9.5 ± 4.1 year), non-Hispanic black (9.7 ± 3.9 years), and Hispanic children (9.0 ± 4.8 years). However, the non-Hispanic black and Hispanic children exhibit a higher BMI (33.3 ± 8.1 and 32.1 ± 8.9 kg/m2, respectively) compared with non-Hispanic white children (30.6 ± 6.0 kg/m2; P < .004).
Age at the first endocrine visit is similar in boys (9.5 ± 4.0 years) and girls (9.5 ± 4.1 year). However, girls composed 57.6% of the referred population and presented a lower BMI z score (2.6 ± 0.6) compared with boys (2.9 ± 1.0; P < .01). Growth records, available for 251 children, indicated that 80.6% of the children had become obese before the age of 6 years. The average interval between the age at which the child became obese and age of referral is 4.3 ± 2.9 years. The distribution of age at obesity onset compared with the age of referral is shown in Fig. 1.
The mean percentage overweight was 81.5 ± 30.1 at baseline and 85.2 ± 33.7 after a follow-up interval of 1.9 ± 2.3 years from the first visit, with a mean percentage change of 4.2 ± 21.9. The above data show that there was an overall trend for these children to gain weight over time, with only 38% of the children exhibiting a decrease in percentage overweight compared with the baseline visit. However, these children were still severely overweight, and only 5 patients at follow-up had an age- and gender-specific BMI below the 95th percentile. No association was found between the weight outcome and the number of visits or the length of follow-up. Reported parental BMI shows that 50% of the mothers and 57.7% of the fathers were obese (BMI >30 kg/m2). A diagnosis of type 2 diabetes was self-reported in 11.4% of parents (16.7% of the non-Hispanic black children, 9.5% of the non-Hispanic white children, and 19% of the Hispanic children).
Bone age records, read by pediatric radiologists, were obtained for 157 children for a variety of reasons: fast growth rate, signs of adrenarche, and height higher than expected on the basis of the child's genetic potential. Forty-seven percent of children had a bone age advancement >2 SD above the mean on the basis of age- and gender-specific reference.18
Fasting glucose was obtained in 97 children, and 2 of them had impaired fasting glucose (>105 mg/dL). Fasting insulin 15 mμ/mL was present in 72 (76.6%) of 94 children. Although the mean age of children with fasting hyperinsulinemia was 12 ± 2.7 years, high fasting insulin levels were present in children as young as 4 years of age (Fig. 2). A random cholesterol level >170 mg/dL was observed in 174 (56%) of 311 children.19 Liver enzymes were measured in 189 children. In this subset, serum aspartate aminotransferase and serum alanine aminotransferase were above normal (45 units/L) in 10% and 5% of children, respectively.
DISCUSSION
This retrospective study described a cohort of overweight children who were referred by primary care physicians to pediatric endocrinologists over a 20-year period. Given the retrospective nature of the study, conducted via chart, growth, and laboratory data review, the data generated must be seen as preliminary and exploratory. Data relative to the criteria for referral were not available. However, it is likely that the referred cohort may be representative of the most severe cases, referred to the subspecialist after the pediatrician's efforts to counsel the family had been unsuccessful. Moreover, family history of overweight may have prompted the referral. In our data set, similar to what was reported in the literature, the severity of overweight was more marked in minorities, yet non-Hispanic white children represented the majority of this cohort of children who were referred for overweight over nearly 2 decades. Because our center represents the only pediatric endocrinology practice in western New York, it is likely that many children from the minority populations are not being referred to the subspecialist. In the population of overweight children who are referred to our clinic, a referral bias may also exist with regard to gender, with girls representing 58% of the cohort despite having a lower BMI z score compared with the referred boys. This finding may be attributable to the higher prevalence of obesity in girls or to the fact that parents, teachers, and physicians may be more attentive to body image in girls compared with boys.20,21
The referral to the pediatric endocrinologist occurs on the average >4 years after the child has become overweight, and growth curves, available for 251 children, indicate that 80.6% of these children become obese in their preschool years. Additional data are needed to examine whether the early onset of obesity may be because the cases referred may be the most severe cases or this is indeed a worrisome trend present in the pediatric population. This finding, coupled with the unsuccessful outcome of "delayed" referral to the subspecialist, underscores the importance of early intervention. Moreover, a period of time is elapsing between the child's reaching the "at risk for overweight" threshold (BMI 85th percentile) and the obesity threshold (BMI 95th percentile). Although not all children who are overweight in early childhood are destined to become obese adolescents and adults, it is essential to recognize the young child as he or she is approaching the "at risk for overweight" threshold. Research is greatly needed to explore whether the child who is entering the "at risk for overweight category" can be prevented from progressing to the overweight one. Perhaps an effective approach to obesity treatment and prevention may be to teach healthier behaviors as early as possible, rather than wait and try to change established unhealthy habits. It was reported recently that pediatricians frequently refer children for nutritional work-up as a result of mild underweight but not for overweight or obesity.22 Some argue that this is the result of underrecognition of the obesity problem, compounded with lack of reimbursement for treating obesity.23 However, it is also possible that the pediatrician may be aware of the ineffectiveness of referring obese children to the nutritionist and/or the pediatric endocrinologist.
This young population of overweight children is already manifesting known obesity comorbidities. Fasting insulin levels were elevated in 76.6% of children who underwent this test. This is not likely to represent a "reliable" prevalence, because insulin was measured only in 94 children, likely as a result of the presence of acanthosis nigricans or symptoms of diabetes. Nevertheless, this is a worrisome finding, especially in view of the fact that elevated fasting insulin levels are present also in young children and 11.4% of parents have type 2 diabetes. The prevalence of type 2 diabetes was almost double in parents of non-Hispanic black (16.7%) and Hispanic children (19%) compared with non-Hispanic white children (9.5%), in keeping with the higher prevalence of type 2 diabetes reported in minorities. However, these data are self-reported and retrospective and thus must be considered exploratory. Moreover, this self-reported percentage is likely to be higher, given the high prevalence of obesity in these parents (>50%) and that type 2 diabetes is often undiagnosed. It is advisable, therefore, for the pediatrician to suggest that parents of overweight children, when overweight themselves, be screened for type 2 diabetes. In addition to the high parental prevalence of type 2 diabetes, the high cholesterol levels observed in 56% of children produces a high risk for developing coronary heart disease.24
Nearly half of these children had significantly advanced bone age, often associated with early sexual development and increased height growth velocity. The latter masks the inappropriate weight gain, which goes unrecognized unless the pediatrician calculates and plots the child's BMI, as recommended by the American Academy of Pediatrics Policy Statement.25 Moreover, if an overweight child is growing along a higher height percentile compared with midparental height, parents should be counseled regarding that the "tall" child with advanced bone age may not be a tall adult. This may induce parents to pursue more urgently weight maintenance for their overweight child.
CONCLUSION
Our data indicate that referral of children who are affected by longstanding overweight to the pediatric endocrinologist is ineffective. We suggest that efforts should be devoted to developing early family-based behavioral-lifestyle intervention programs to be made available to pediatricians. These programs should enable pediatricians to target the "at risk for overweight" preschool children and their likely overweight parents.
FOOTNOTES
Accepted Sep 2, 2004.
No conflict of interest declared.
REFERENCES
Strauss RS, Pollack HA. Epidemic increase in childhood overweight, 1986–1998. JAMA. 2001;286 :2845 –2848
Ogden CL, Flegal KM, Carroll MD, Johnson CL. Prevalence and trends in overweight among US children and adolescents, 1999–2000. JAMA. 2002;288 :1728 –1732
Troiano RP, Flegal KM. Overweight children and adolescents: description epidemiology, and demographics. Pediatrics. 1998;10 :497 –504
Guo SS, Chumlea WC. Tracking of body mass index in children in relation to overweight in relation to overweight in adulthood. Am J Clin Nutr. 1999;70(suppl) :145S –148S
Whitaker RC, Wright JA, Pepe MS, Seidel KD, Dietz WH. Predicting obesity in young adulthood from childhood and parental obesity. N Engl J Med. 1997;337 :869 –873
Sinha R, Fisch G, Teague B, et al. Prevalence of impaired glucose tolerance among children and adolescents with marked obesity. N Engl J Med. 2002;346 :802 –810
Manson JE, Cloditz GA, Stampfer MJ, et al. A prospective study of obesity and risk of coronary heart disease in women. N Engl J Med. 1990;322 :882 –889
Must A, Jacques PF, Dallal GE, Bajema CY, Dietz WH. Long-term morbidity and mortality of overweight adolescents. N Engl J Med. 1992;327 :1350 –1355
Goran MI, Ball GDC, Cruz ML. Obesity and risk of type 2 diabetes and cardiovascular disease in children and adolescents. J Clin Endocrinol Metab. 2003;88 :1417 –1427
Hillier TA, Pedula KL. Characteristics of an adult population with newly diagnosed type 2 diabetes: the relation of obesity and age of onset. Diabetes Care. 2001;24 :1522 –1527
Libman IM, Pietropaolo M, Arslanian SA, LaPorte RE, Becker DL. Changing prevalence of overweight children and adolescents at onset of insulin-treated diabetes. Diabetes Care. 2003;26 :2871 –2875
Schwimmer JB, Burwinkle TM, Varni JW. Health-related quality of life severely obese children and adolescents. JAMA. 2003;289 :1813 –1819
Epstein LH, Roemmich JN, Raynor HA. Behavioral therapy in the treatment of pediatric obesity. Pediatr Clin North Am. 2001;48 :981 –993
Tuomilehto J, Lindstrom J, Eriksson JG, et al., For the Finish Diabetes Prevention Study Group. Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. N Engl J Med. 2001;344 :1343 –1350
Centers for Disease Control and Prevention. Pediatric Nutrition Surveillance System—United States, 1980–1991. MMWR Morb Mortal Wkly Rep. 1992;41 :SS1–SS24
Institute of Medicine. WIC Nutrition Risk Criteria: A Scientific Assessment. Washington, DC: National Academy Press; 1996
Greulich WW, Pyle SI. Radiographic Atlas of Skeletal Development of the Hand and Wrist. 2nd ed. Palo Alto, CA: Stanford University Press; 1959
Committee on Nutrition. American Academy of Pediatrics: cholesterol in childhood. Pediatrics. 1998;101 :141 –147
Troiano RP, Flegal KM, Kuczmarski RJ. Overweight prevalence and trends for children and adolescents. The National Health and Nutrition Examination Survey, 1963 to 1991. Arch Pediatr Adolesc Med. 1995;149 :1085 –1091
Storey ML, Forshee RA, Weaver AR, Sansalone WR. Demographic and lifestyle factors associated with body mass index among children and adolescents. Int J Food Sci Nutr. 2003;54 :491 –503
Miller LA, Grunwald G, Johnson SL, Krebs NF. Disease severity at time of referral for pediatric failure to thrive and obesity: time for a paradigm shift Pediatrics. 2002;141 :121 –124
Tershakovec A, Watson MH, Wenner W Jr, Marx AL. Insurance reimbursement for the treatment of obesity in children. Pediatrics. 1999;134 :573 –578
Raitakari OT, Juonala M, Kahonen M, et al. Cardiovascular risk factors in childhood and carotid artery intima-media thickness in adulthood. The Cardiovascular Risk in Young Finns Study. JAMA. 2003;290 :2277 –2283
American Academy of Pediatrics, Committee on Nutrition. Policy Statement, Prevention of pediatric overweight and obesity. Pediatrics. 2003;112 :424 –428(Teresa Quattrin, MD, Emil)
ABSTRACT
Objective. The objective of this study was to characterize a population of obese children who were referred to a pediatric endocrinology clinic and to analyze the outcome of the referral.
Methods. Children who were referred for obesity and seen at least twice between January 1984 and July 2003 were included in this retrospective study. Demographic, clinical, and, when available, laboratory (fasting glucose and insulin, random cholesterol, and liver function tests) and bone age data were abstracted from the medical record at the first and last endocrine evaluations. Self-reported parental height, weight, and family history of diabetes were also entered in the database. Records from the pediatrician were used to identify the age of onset of obesity.
Results. The database included 587 children (mean age at referral: 9.5 years) with a preponderance of non-Hispanic white children (75.6%) and female gender (57.6%). Growth records in 251 children indicated that 80.6% of the children had become obese before the age of 6 years and were referred 4.3 ± 2.9 years after having become obese. At follow-up, 38% of the children exhibited a decreased percentage of overweight compared with the baseline visit, but only 5 children had an age- and gender-specific BMI below the 95th percentile. Cholesterol and fasting insulin were elevated in 174 of 311 and 72 of 94 children, respectively. Bone age radiographic records for 157 patients showed significant advancement in 46%. Half of the mothers and 57.7% of fathers were obese, and type 2 diabetes was self-reported in 11.4% parents.
Conclusions. In the majority of this predominantly non-Hispanic white referred sample of obese children, overweight started in the preschool years. The referral to the endocrinologist, occurring after a prolonged interval from the obesity onset, was ineffective in treating obesity. Hyperinsulinemia and hypercholesterolemia are often present also at a young age. These obesity comorbidities in association with high prevalence of parental obesity and type 2 diabetes expose these youths to high risk for developing type 2 diabetes and coronary heart disease. Our data underscore the need for early family-based behavioral-lifestyle intervention programs to be made available to pediatricians, enabling them to target the "at risk for overweight" preschool children and their likely overweight parents.
Key Words: pediatric obesity onset outcome hyperinsulinemia
The prevalence of obesity has increased dramatically in recent years across all pediatric ages.1–3 Obese children are at risk for becoming obese adults,4,5 and many known comorbidities observed in obese adults are now observed more frequently in youths, type 2 diabetes representing a dramatic example.6–11 The psychological impact of obesity is just as devastating as the medical implication, with the overweight children having a 5-fold increased risk for low health-related quality of life, a risk similar to what is observed in children who are affected by cancer.12 Finally, the economic burden of childhood obesity has also increased 3-fold in the past 20 years, reaching $127 million per year.13
Family-based behavioral modification treatments have been the only therapeutic modality to demonstrate long-term success in the treatment of pediatric obesity.14,15 However, the expertise needed, manpower, and overall cost have prevented thus far the translation of these interventions to the population at large. Pediatricians who attempt to educate the child and the family are often unsuccessful and refer the child to the nutritionist and/or pediatric endocrinologist. The criteria for referring the overweight child to the pediatric endocrinologist and the referral's outcome are unclear. The aim of our study was to characterize a population of obese children who were referred to a pediatric endocrinology clinic and to analyze the outcome of the referral.
METHODS
Using a database pertinent to children who were referred to a pediatric endocrine clinic located in a tertiary regional hospital, we identified all children who had a primary or a secondary International Classification of Diseases code of "exogenous obesity" between January 1984 and July 2003. We excluded children with diabetes, untreated thyroid disorder, Prader-Willi syndrome, and other endocrine disorders or syndromes associated with obesity. The patients were included in the database only after confirming the International Classification of Diseases code by calculating BMI as outlined below. During the visits, the child and the accompanying caregiver received counseling on lifestyle changes and verbal and written guidelines regarding healthy nutritional habits and physical activity. Children and families who had not already seen a nutritionist were advised to seek a consultation and provided with the names and numbers of dietitians who are experienced in pediatric care. The families were also made aware that counseling was available from 2 psychoendocrinologists who often met with families in the clinic.
Demographic data, height, weight, heart rate, blood pressure, and, when available, laboratory and bone age data were abstracted from the pediatric endocrine medical record at the first and last endocrine evaluations. The laboratory data included fasting glucose and insulin, random cholesterol, and liver function tests. Using information reported by the caregiver who accompanied the child to the endocrine evaluation, parents' height; weight; and family history of diabetes, hypertension, and heart disease were also entered in the database.
Growth charts sent by the referring primary care physicians were used to determine age at the onset of obesity. Only growth charts that had consistent yearly measurements and were performed by the same pediatric office were used, and the timing of onset of obesity was never extrapolated, rather it was obtained by the first height/weight measurement that yielded a BMI measurement above the 95th percentile. In children who were aged 2 years or older, obesity and overweight onset were defined by the age at which BMI was 95th or 85th percentile, respectively for age and gender. BMI was calculated as weight in kilograms divided by height in meters squared (kg/m2). When growth data revealed that a child's BMI was already >95th percentile at 2 years of age, the onset of obesity was defined by the age at which the child as an infant first presented length:weight ratio >95th percentile, in keeping with recommendations from the Special Supplemental Nutrition Program for Women, Infants, and Children.16,17 The child's percentage overweight at the first endocrine clinic visit was compared with the percentage overweight at the most recent follow-up. Percentage overweight was calculated by comparing the child's actual BMI with that child's age and gender BMI at the 50th percentile according to the following formula: present BMI/BMI at the 50th %ile x 100. Data were expressed as mean ± SD and analyzed in SPSS (version 8.1) using Mann-Whitney U, Wilcoxon matched pairs signed ranks, and Kruskal Wallis.
RESULTS
The database includes 587 medical records and is composed of 75.6% non-Hispanic white children, 19.4% non-Hispanic black children, 3.4% Hispanic children, and 1.5% children belonging to other races. The mean age at the first endocrine clinic visit is similar in non-Hispanic white (9.5 ± 4.1 year), non-Hispanic black (9.7 ± 3.9 years), and Hispanic children (9.0 ± 4.8 years). However, the non-Hispanic black and Hispanic children exhibit a higher BMI (33.3 ± 8.1 and 32.1 ± 8.9 kg/m2, respectively) compared with non-Hispanic white children (30.6 ± 6.0 kg/m2; P < .004).
Age at the first endocrine visit is similar in boys (9.5 ± 4.0 years) and girls (9.5 ± 4.1 year). However, girls composed 57.6% of the referred population and presented a lower BMI z score (2.6 ± 0.6) compared with boys (2.9 ± 1.0; P < .01). Growth records, available for 251 children, indicated that 80.6% of the children had become obese before the age of 6 years. The average interval between the age at which the child became obese and age of referral is 4.3 ± 2.9 years. The distribution of age at obesity onset compared with the age of referral is shown in Fig. 1.
The mean percentage overweight was 81.5 ± 30.1 at baseline and 85.2 ± 33.7 after a follow-up interval of 1.9 ± 2.3 years from the first visit, with a mean percentage change of 4.2 ± 21.9. The above data show that there was an overall trend for these children to gain weight over time, with only 38% of the children exhibiting a decrease in percentage overweight compared with the baseline visit. However, these children were still severely overweight, and only 5 patients at follow-up had an age- and gender-specific BMI below the 95th percentile. No association was found between the weight outcome and the number of visits or the length of follow-up. Reported parental BMI shows that 50% of the mothers and 57.7% of the fathers were obese (BMI >30 kg/m2). A diagnosis of type 2 diabetes was self-reported in 11.4% of parents (16.7% of the non-Hispanic black children, 9.5% of the non-Hispanic white children, and 19% of the Hispanic children).
Bone age records, read by pediatric radiologists, were obtained for 157 children for a variety of reasons: fast growth rate, signs of adrenarche, and height higher than expected on the basis of the child's genetic potential. Forty-seven percent of children had a bone age advancement >2 SD above the mean on the basis of age- and gender-specific reference.18
Fasting glucose was obtained in 97 children, and 2 of them had impaired fasting glucose (>105 mg/dL). Fasting insulin 15 mμ/mL was present in 72 (76.6%) of 94 children. Although the mean age of children with fasting hyperinsulinemia was 12 ± 2.7 years, high fasting insulin levels were present in children as young as 4 years of age (Fig. 2). A random cholesterol level >170 mg/dL was observed in 174 (56%) of 311 children.19 Liver enzymes were measured in 189 children. In this subset, serum aspartate aminotransferase and serum alanine aminotransferase were above normal (45 units/L) in 10% and 5% of children, respectively.
DISCUSSION
This retrospective study described a cohort of overweight children who were referred by primary care physicians to pediatric endocrinologists over a 20-year period. Given the retrospective nature of the study, conducted via chart, growth, and laboratory data review, the data generated must be seen as preliminary and exploratory. Data relative to the criteria for referral were not available. However, it is likely that the referred cohort may be representative of the most severe cases, referred to the subspecialist after the pediatrician's efforts to counsel the family had been unsuccessful. Moreover, family history of overweight may have prompted the referral. In our data set, similar to what was reported in the literature, the severity of overweight was more marked in minorities, yet non-Hispanic white children represented the majority of this cohort of children who were referred for overweight over nearly 2 decades. Because our center represents the only pediatric endocrinology practice in western New York, it is likely that many children from the minority populations are not being referred to the subspecialist. In the population of overweight children who are referred to our clinic, a referral bias may also exist with regard to gender, with girls representing 58% of the cohort despite having a lower BMI z score compared with the referred boys. This finding may be attributable to the higher prevalence of obesity in girls or to the fact that parents, teachers, and physicians may be more attentive to body image in girls compared with boys.20,21
The referral to the pediatric endocrinologist occurs on the average >4 years after the child has become overweight, and growth curves, available for 251 children, indicate that 80.6% of these children become obese in their preschool years. Additional data are needed to examine whether the early onset of obesity may be because the cases referred may be the most severe cases or this is indeed a worrisome trend present in the pediatric population. This finding, coupled with the unsuccessful outcome of "delayed" referral to the subspecialist, underscores the importance of early intervention. Moreover, a period of time is elapsing between the child's reaching the "at risk for overweight" threshold (BMI 85th percentile) and the obesity threshold (BMI 95th percentile). Although not all children who are overweight in early childhood are destined to become obese adolescents and adults, it is essential to recognize the young child as he or she is approaching the "at risk for overweight" threshold. Research is greatly needed to explore whether the child who is entering the "at risk for overweight category" can be prevented from progressing to the overweight one. Perhaps an effective approach to obesity treatment and prevention may be to teach healthier behaviors as early as possible, rather than wait and try to change established unhealthy habits. It was reported recently that pediatricians frequently refer children for nutritional work-up as a result of mild underweight but not for overweight or obesity.22 Some argue that this is the result of underrecognition of the obesity problem, compounded with lack of reimbursement for treating obesity.23 However, it is also possible that the pediatrician may be aware of the ineffectiveness of referring obese children to the nutritionist and/or the pediatric endocrinologist.
This young population of overweight children is already manifesting known obesity comorbidities. Fasting insulin levels were elevated in 76.6% of children who underwent this test. This is not likely to represent a "reliable" prevalence, because insulin was measured only in 94 children, likely as a result of the presence of acanthosis nigricans or symptoms of diabetes. Nevertheless, this is a worrisome finding, especially in view of the fact that elevated fasting insulin levels are present also in young children and 11.4% of parents have type 2 diabetes. The prevalence of type 2 diabetes was almost double in parents of non-Hispanic black (16.7%) and Hispanic children (19%) compared with non-Hispanic white children (9.5%), in keeping with the higher prevalence of type 2 diabetes reported in minorities. However, these data are self-reported and retrospective and thus must be considered exploratory. Moreover, this self-reported percentage is likely to be higher, given the high prevalence of obesity in these parents (>50%) and that type 2 diabetes is often undiagnosed. It is advisable, therefore, for the pediatrician to suggest that parents of overweight children, when overweight themselves, be screened for type 2 diabetes. In addition to the high parental prevalence of type 2 diabetes, the high cholesterol levels observed in 56% of children produces a high risk for developing coronary heart disease.24
Nearly half of these children had significantly advanced bone age, often associated with early sexual development and increased height growth velocity. The latter masks the inappropriate weight gain, which goes unrecognized unless the pediatrician calculates and plots the child's BMI, as recommended by the American Academy of Pediatrics Policy Statement.25 Moreover, if an overweight child is growing along a higher height percentile compared with midparental height, parents should be counseled regarding that the "tall" child with advanced bone age may not be a tall adult. This may induce parents to pursue more urgently weight maintenance for their overweight child.
CONCLUSION
Our data indicate that referral of children who are affected by longstanding overweight to the pediatric endocrinologist is ineffective. We suggest that efforts should be devoted to developing early family-based behavioral-lifestyle intervention programs to be made available to pediatricians. These programs should enable pediatricians to target the "at risk for overweight" preschool children and their likely overweight parents.
FOOTNOTES
Accepted Sep 2, 2004.
No conflict of interest declared.
REFERENCES
Strauss RS, Pollack HA. Epidemic increase in childhood overweight, 1986–1998. JAMA. 2001;286 :2845 –2848
Ogden CL, Flegal KM, Carroll MD, Johnson CL. Prevalence and trends in overweight among US children and adolescents, 1999–2000. JAMA. 2002;288 :1728 –1732
Troiano RP, Flegal KM. Overweight children and adolescents: description epidemiology, and demographics. Pediatrics. 1998;10 :497 –504
Guo SS, Chumlea WC. Tracking of body mass index in children in relation to overweight in relation to overweight in adulthood. Am J Clin Nutr. 1999;70(suppl) :145S –148S
Whitaker RC, Wright JA, Pepe MS, Seidel KD, Dietz WH. Predicting obesity in young adulthood from childhood and parental obesity. N Engl J Med. 1997;337 :869 –873
Sinha R, Fisch G, Teague B, et al. Prevalence of impaired glucose tolerance among children and adolescents with marked obesity. N Engl J Med. 2002;346 :802 –810
Manson JE, Cloditz GA, Stampfer MJ, et al. A prospective study of obesity and risk of coronary heart disease in women. N Engl J Med. 1990;322 :882 –889
Must A, Jacques PF, Dallal GE, Bajema CY, Dietz WH. Long-term morbidity and mortality of overweight adolescents. N Engl J Med. 1992;327 :1350 –1355
Goran MI, Ball GDC, Cruz ML. Obesity and risk of type 2 diabetes and cardiovascular disease in children and adolescents. J Clin Endocrinol Metab. 2003;88 :1417 –1427
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