Pubertal African-American girls expend less energy at rest and during physical activity than Caucasian girls.

Between 1963 and 1991, the most dramatic increases in the prevalence of overweight in the United States have been reported in African-American girls. Lower basal energy expenditure and lack of physical activity are believed to be risk factors for excessive weight gain. We hypothesized that energy expenditure at rest and during physical activity are lower in pubertal African-American girls than in Caucasian girls. Basal metabolic rate and sleeping energy expenditure of 40 Caucasian and 41 African-American pubertal girls (matched for age, physical characteristics, body fat, and energy intake) were measured by whole-room calorimetry, energy expended for physical activity by the doubly labeled water method, sexual maturity by physical examination, body composition by dual-energy x-ray absorptiometry, physical fitness by treadmill testing, and energy intake by 3-day food record. After adjusting for soft lean tissue mass, the basal energy expenditure (1333 +/- 132 vs. 1412 +/- 132 kcal/day, P = 0.01) and energy expended for physical activity (809 +/- 637 vs. 1271 +/- 162 kcal/day, P < 0.01) were significantly lower in the African-American girls than in the Caucasian girls. The differences remained the same after controlling for differences in sexual maturity and/or physical fitness. The lower energy expenditure of the pubertal African-American girls suggests that they are at a higher risk of becoming overweight than their Caucasian counterparts.

Serum leptin concentrations in Caucasian and African-American girls.

Because African-American girls are heavier, taller, and mature earlier than Caucasian girls, we hypothesized that the serum leptin concentration differs between the two groups. Serum leptin concentrations were measured by immunoassay in 12-h fasted blood samples collected from 79 Caucasian and 57 African-American girls between 8 and 17 yr of age. Body composition was measured by dual-energy x-ray absorptiometry, sexual maturity by physical examination, and physical fitness by treadmill testing. Serum leptin concentrations were positively correlated (P < 0.01) with maturation, body fatness, and insulin and were higher (6.6 ng/mL, P < 0.01) in the African-American girls after adjusting for age. The difference remained significant (P < 0.01) but was reduced to 3.2 ng/mL after controlling for differences in maturation, fat mass, and physical fitness. The higher serum leptin levels might play an important role in the accelerated growth and sexual maturation of African-American girls.

Are basal metabolic rate prediction equations appropriate for female children and adolescents?

The basal metabolic rate (BMR), which accounts for 50-70% of total energy expenditure, is essential for estimation of patient and population energy needs. Numerous equations have been formulated for prediction of human BMR. Most equations in current use are based on measurements of Caucasians performed more than four decades ago. We evaluated 10 prediction equations commonly used for estimation of BMR in 76 Caucasian and 42 African-American girls between 8 and 17 yr of age against BMR measured by whole-body calorimetry. The majority of the prediction equations (9 of 10) overestimated BMR by 60 +/- 46 kcal/day (range, 15-176 kcal/day). This overestimation was found to be significantly greater (P < 0.05) for African-American (77 +/- 17 kcal/day) than for Caucasians (25 +/- 17 kcal/day) in six equations, controlling for age, weight, and sexual maturity. We conclude that ethnicity is an important factor in estimation of the BMR and that the current prediction equations are not appropriate for accurate estimation of the BMR of individual female children and adolescents.

Anthropometric measurements and estimating body composition in ballet dancers.

The purpose of this study was to develop and cross-validate an equation for estimating fat-free mass (FFM) in female ballet dancers. One hundred twelve, 11- to 25-yr old, female dancers had FFM measured by total body electrical conductivity (TOBEC) and anthropometrics, including skinfold and circumference measurements. The regression equation that best estimated FFM in the dancers was FFM = 0.73 x body weight (kg) + 3.0, (R2 = 88%, SEE = 1.5 kg, P < 0.001). This equation was then cross-validated on a separate group of 23 female dancers who also had FFM measured by TOBEC. FFM estimated by this equation correlated with FFM measured by TOBEC (r = 0.94, SEE = 0.9 kg), and the difference in the FFM values using the two methods (the equation and TOBEC) did not change with the size of the FFM of the dancers. FFM in accomplished female ballet dancers can be best estimated from body weight alone. This is related to the homogeneity of body size and body composition in female ballet dancers at this level.

Body composition in ballet dancers measured by total body electrical conductivity.

The purpose of this study was to describe the body composition of adolescent and young adult ballet dancers using total body electrical conductivity (TOBEC). We studied 112 female and 33 male dancers. The mean ages were 15.0 +/- 2.0 and 18.7 +/- 3.1 yr for females and males, respectively. The mean percent body fat (PBF) values were 20.1 +/- 3.6% for the females and 14.5 +/- 4.2% for the males. Age and pubertal development were not significantly related to PBF in the females. Age and pubertal status were significantly inversely related to PBF in the males. There was no difference in dance history, percent body fat, and abdominal/hip or waist/hip ratios in eumenorrheic vs amenorrheic dancers. Estimated calorie intake indicated that dancers with menstrual abnormalities had lower calorie intake than those with normal menses. This is the largest group of ballet dancers whose body composition has been studied. Our PBF measurements are higher than in previous reports using hydrodensitometry, which may have underestimated body fat by not accounting for the increased bone density in the lower extremities of dancers. Our data suggest that previous measurements of PBF in dancers are underestimates; these new data challenge our concept of PBF values in dancers.

Total body water and fat-free mass in ballet dancers: comparing isotope dilution and TOBEC.

Nine male and seven female high level ballet students had total body water (TBW) measured by two methods: 1) H2(18)O isotope dilution and 2) total body electrical conductivity (TOBEC). TBW from TOBEC measurements was calculated using an equation previously derived from adults, and these new measurements correlated highly with TBW by isotope dilution (r = 0.99, SEE = 0.78 kg). However, the difference between these two methods increased as TBW increased. Therefore, a new equation (ballet equation) was developed which improved the prediction of TBW for individuals (SEE = 0.69 kg) and for which the difference in TBW between isotope dilution and TOBEC was independent of the TBW value. Using age-adjusted hydration constants, the TBW measurements by isotope dilution were converted to fat-free mass, and these values were used to develop an accurate equation for predicting fat-free mass from TOBEC measurements (r = 0.99, SEE = 0.91 kg). In addition, we measured TBW and calculated FFM in ten control adolescents and used these values to develop equations for predicting TBW (r = 0.99, SEE = 1.01 kg) and FFM (r = 0.99, SEE = 1.42 kg) in a combined group of adolescent dancers and non-dancers. Total body water and fat-free mass can be accurately measured in adolescent ballet dancers and non-dancers using TOBEC.

Ethnicity affects aerobic fitness in US adolescent girls.

The purpose of this investigation was to determine whether aerobic fitness (VO2max) differed between black (N = 40) and white (N = 53) adolescent girls who were similar in age (13.5 yr) and percent body fat (24.6%). Expired gases were collected continuously while each girl performed a standard Bruce protocol to volitional exhaustion on a motorized treadmill (TM). Heart rates (HR) were measured during the exercise testing via telemetry. Fat-free mass (FFM) was estimated with total body electrical conductivity (TOBEC). Average (+/- SD) maximum HR (black = 194 +/- 7; white = 198 +/- 8) and respiratory exchange ratios (black = 1.17 +/- 0.08; white = 1.22 +/- 0.09) did not differ between subject groups. Aerobic fitness was significantly lower (P < 0.01) lower in black versus white girls when VO2max was expressed relative to body weight (31.8 +/- 5.8 vs 38.5 +/- 6.8 ml.kg(-1).min(-1)) and body weight raised to the 0.67 power (120.9 +/- 19.5 vs 138.5 +/- 20.7 ml.kg(-0.67).min-1). Treadmill time to exhaustion was significantly less (P < 0.01) in the black (8.49 +/- 1.30 min) versus white (9.41 +/- 1.60) subjects. Also, black subjects demonstrated less ability to utilize O2 during maximal exercise at a given FFM. This suggests the black girls' FFM contained a smaller percentage of skeletal muscle mass that could be utilized during treadmill exercise. It is possible that lower aerobic fitness values seen in the black girls are related to a combination of anatomical, physiological and/or behavioral factors.

Interviewing techniques with adolescents in primary care.

PURPOSE: Privacy is of utmost concern to adolescents seeking advice regarding life-style and behavior choices. Lack of privacy and confidential health services are barriers to adolescents' access to health care. This study describes primary care physicians' practices with regard to inviting parent(s) to leave the room in order to interview the teen alone, and the factors associated with use of this technique. METHOD: A cross-sectional random survey of 1,630 pediatricians, internists, and family practitioners in a large metropolitan area was performed using a confidential mailed questionnaire. RESULTS: The majority of the physicians were in private practice, male, board certified, Caucasian, and did not have a subspecialty. Forty-nine percent of the respondents "almost always" or "always" invite parent(s) to leave the room in order to interview the teen alone. Physicians who were female, board certified, and completed residency from 1974-94 were most likely to use this technique. Among physicians who frequently employ this strategy, the decision to interview the teen alone varied according to the clinical scenario. Using logistic regression analysis, only gender and board certification were significantly related to use of this interviewing method. CONCLUSION: A large proportion of physicians do not interview their adolescent patients alone, therefore, not affording them privacy to discuss confidential health concerns. Future research should focus on developing and validating methods to teach physicians skills to interview adolescents privately.

Validity of self-assessment of pubertal maturation in African American and European American adolescents.

PURPOSE: To evaluate interobserver reliability of physician assessments of pubertal maturation and to evaluate the validity of self-assessment compared to physician assessments of pubertal maturation by girls in a multiethnic sample. METHODS: The study design is descriptive. A total of 107 8-17-year-old healthy volunteers from settings with large minority populations in the Houston metropolitan area were recruited for a study on adolescents' energy needs. The two outcome measures were interobserver reliability between two physicians' assessments of breast and pubic hair, and the self-assessment of breast and pubic hair maturation compared to physicians' assessments. RESULTS: The kappa coefficient for physician interobserver agreement for breast maturation was 0.5. The kappa coefficient for physician interobserver agreement for assessment of pubic hair was 0.79. The kappa coefficient for the validity of self-assessment of breast development was 0.34, and that for self-assessment of pubic hair was 0.37. CONCLUSION: Interobserver agreement for physician assessment of breast maturation was low and self-assessment of breast maturation was not reliable in this group of adolescent girls. However, whereas physician interobserver agreement for pubic hair was good, self-assessment of pubic hair maturation was not reliable in this group of adolescent girls.

The preparticipation sports examination.

Although not a comprehensive health evaluation, the PSE is viewed as such by many parents and adolescents. In this regard, these athletes are getting a lower standard of care than recommended; however, the mechanism wherein the PSE can become a cost-effective comprehensive examination has not been established. The PSE is one method of injury prevention in that it is designed to identify medical conditions that would be worsened by participation in exercise and sports. Pediatricians should use this examination as a quality control point during the year to assess how medical conditions and musculoskeletal injuries have been diagnosed and managed in the context of sports.

Prophylactic ankle bracing.

Many choices are available to athletes seeking an ankle support. The time-honored tradition of ankle taping with adhesive tape does offer protection against ankle sprains during activity. Laced stabilizers offer an equal or possibly greater amount of support, are less costly and easier to apply, and can be retightened frequently during activity. The physician should become familiar with one of these two methods and choose one based on availability and feasibility in the community. The air stirrup may be indicated for patients with a history of ankle injury who are undergoing a graduated rehabilitation program. Nevertheless, the air stirrup has not been shown to provide significantly greater inversion restriction than taping or lace-on braces and is not recommended as a first-line method of support for individuals with no history of recent ankle sprain. High-top shoes are better when the ankle is taped, although low-top shoes are better when a laced stabilizer is worn. Elastic guards help reduce ankle edema but do not provide ankle stability.

Body composition in adolescent athletes.

This article has set out to provide basic knowledge about body composition in athletic and nonathletic adolescents and young adults and to provide the practicing physician with methods of making body composition assessment. We suggest the physician approach the adolescent athlete who requests information about body composition in the following way: 1. Calculate the ideal body weight. 2. Estimate the percentage of body fat, realizing the errors associated with each method. If a body composition laboratory is available, use that equipment. In the absence of this equipment, we recommend the equations of Slaughter et al, given earlier. 3. The athlete should be given a range of percentage of body fat values measured in other athletes of the same gender and sport. Health and performance should be monitored as the athlete attempts to achieve or maintain body composition in this range. 4. If the athlete has an interest in altering body composition, then recommend the athlete seek the advice of a professional who has expertise in nutrition and physiology.

Amenorrhea, osteopenia, and the female athlete.

Athletic amenorrhea is a problem because it is associated with an increased risk of injuries and potentially an increased risk of osteoporosis in later life. This article gives suggestions for the evaluation of the athlete with amenorrhea and for treatment protocols. Primary care physicians should routinely screen female adolescent athletes for amenorrhea and, if athletic amenorrhea is present, initiate treatment or referral for treatment for this important problem with short- and long-term complications.

Leukocyte esterase dipstick as a rapid screening test for vaginitis and cervicitis.

STUDY OBJECTIVE: To assess the ability of vaginal and cervical leukocyte esterase (LE) dipstick to detect vaginitis and cervicitis. DESIGN: A prospective, cross-sectional study to assess the ability of the LE dipstick of vaginal secretions to detect trichomonads, candida, and bacterial vaginosis and the LE dipstick of vaginal and cervical secretions to detect gonococcal and chlamydia infection and polymorphonuclear cells (PMNs). SETTING: An inner-city shelter facility clinic. PARTICIPANTS: 183 sexually active, nonmenstruating females aged 13-21 years (Mean = 17.7, SD = 1.98 years): 47% black, 40% white, and 11% Hispanic. OUTCOME MEASURES: Sensitivity (SN), specificity (SP), positive and negative predictive values (PVP, PVN), with 95% confidence intervals, of vaginal and cervical LE dipstick > or = trace in detecting vaginal and cervical infections. RESULTS: A positive vaginal LE had a moderately high SN and PVN but poor SP and PVP in detecting trichomonas and candida vaginitis and bacterial vaginosis. A positive vaginal and cervical LE had a high SN and PVN but poor SP and PVP in detecting gonorrhea and chlamydia infection. A positive cervical LE had a moderate SN and low SP in detecting PMNs on Gram stain. CONCLUSIONS: The LE dipstick of vaginal and cervical secretions was only a moderately good screening test for vaginal infection but a good screening test for cervical infection.

Management of ankle sprains.

This article reviewed the basics of ankle diagnosis and rehabilitation. It is hoped that after reading this, pediatricians will have more confidence in caring for these injuries.