The National Osteoporosis Foundation's position statement on peak bone mass development and lifestyle factors: a systematic review and implementation recommendations.

Lifestyle choices influence 20-40 % of adult peak bone mass. Therefore, optimization of lifestyle factors known to influence peak bone mass and strength is an important strategy aimed at reducing risk of osteoporosis or low bone mass later in life. The National Osteoporosis Foundation has issued this scientific statement to provide evidence-based guidance and a national implementation strategy for the purpose of helping individuals achieve maximal peak bone mass early in life. In this scientific statement, we (1) report the results of an evidence-based review of the literature since 2000 on factors that influence achieving the full genetic potential for skeletal mass; (2) recommend lifestyle choices that promote maximal bone health throughout the lifespan; (3) outline a research agenda to address current gaps; and (4) identify implementation strategies. We conducted a systematic review of the role of individual nutrients, food patterns, special issues, contraceptives, and physical activity on bone mass and strength development in youth. An evidence grading system was applied to describe the strength of available evidence on these individual modifiable lifestyle factors that may (or may not) influence the development of peak bone mass (Table 1). A summary of the grades for each of these factors is given below. We describe the underpinning biology of these relationships as well as other factors for which a systematic review approach was not possible. Articles published since 2000, all of which followed the report by Heaney et al. [1] published in that year, were considered for this scientific statement. This current review is a systematic update of the previous review conducted by the National Osteoporosis Foundation [1]. [Table: see text] Considering the evidence-based literature review, we recommend lifestyle choices that promote maximal bone health from childhood through young to late adolescence and outline a research agenda to address current gaps in knowledge. The best evidence (grade A) is available for positive effects of calcium intake and physical activity, especially during the late childhood and peripubertal years-a critical period for bone accretion. Good evidence is also available for a role of vitamin D and dairy consumption and a detriment of DMPA injections. However, more rigorous trial data on many other lifestyle choices are needed and this need is outlined in our research agenda. Implementation strategies for lifestyle modifications to promote development of peak bone mass and strength within one's genetic potential require a multisectored (i.e., family, schools, healthcare systems) approach.

Peak Vertical Jump Power as a Marker of Bone Health in Children.

The objective of this investigation was to evaluate the accuracy of peak vertical jump power (VJP) to identify children with bone mineral density (BMD) below average, defined as BMD measured by DXA and adjusted for body height at the whole body less head≤- 1.0 standard deviation (SD). The sample included 114 boys and girls aged 8.5±0.4 years old. VJP was estimated from a countermovement jump performed on a contact mat using the measured flight time to calculate the height of rise of the center of gravity. Logistic regression analysis revealed that the odds ratio of having BMD≤1.0 SD decreased 1.2% per watt of power and the probability of BMD below average was 75.6% higher in boys than in girls with the same peak power jump. Receiver operating characteristic analysis showed that the best trade-off between sensitivity and specificity to identify children with BMD<- 1.0 SD was 635 watts in boys (sensitivity=63.3%; specificity=69.2%; AUC=0.816, 95% CI: 0.681-0.95; p<0.001) and 515 watts in girls (sensitivity=75.0%; specificity=77.0%; AUC=0.849, 95% CI: 0.698-0.999; p=0.002). These cut-off values correspond to a vertical jump of 19.9 cm and 20.5 cm in 8-year-old boys and girls, respectively. The VJP showed a reasonable sensitivity and specificity as well good discriminant ability to identify children with BMD below average.

Influence of physical activity and skeleton geometry on bone mass at the proximal femur in 10- to 12-year-old children--a longitudinal study.

UNLABELLED: Physical activity (PA) have long been identified as a determining factor of the mineralization of the skeleton, particularly in children. Our research supports the hypothesis that the geometry of the pelvis and proximal femur (PF) might moderate the effect of PA in the relative mineralization of the PF subregions. INTRODUCTION: Using a longitudinal observational study with two evaluations and a 1-year follow-up interval, we investigated the influence of PA and skeletal geometry in bone mineral density (BMD) and bone mass distribution at the PF in 96 girls and 81 boys (10-12 years). It is plausible that the geometry of the pelvis-PF structure moderates mechanical forces exerted at the hip and therefore creates different degrees of mineralization among PF subregions. METHODS: Whole body and left hip dual X-ray absorptiometry scans were used to derive geometric measures of the pelvis-inter-acetabular distance (IAD) and PF abductor lever arm (ALA). BMD was measured at the integral, superolateral (SL), and inferomedial (IM) femoral neck (FN), and at the trochanter (TR). These subregions were used to represent bone mass distribution via three BMD ratios: FN/PF, IM/SL, and TR/PF. PA was measured using accelerometry and a bone-specific PA questionnaire (BPAQ). RESULTS: A longitudinal data approach revealed BPAQ as a positive predictor for all BMD variables (p < 0.05) except TR BMD in girls and FN BMD in boys. Comparing the most active with the less-active participants, the greatest benefits of PA were observed at the FN of the girls with the lowest IAD (p < 0.001), at the FN of the boys with the highest IAD (p < 0.001) and at the TR of the boys with the lowest ALA (p < 0.01). CONCLUSIONS: Geometric measures of IAD and ALA seem to moderate the effect of PA role in the relative mineralization of the PF regions. On the other hand, absolute BMD levels appear to be determined by mechanical loading.

[Status quo of facet joint replacement]. / Status quo des Facettengelenkersatzes.

This review, regarding facet joint replacement, includes the presentation of six different implant systems from five US firms and one Swiss company. The implant systems are introduced for motion retaining replacement of the lumbar facet joints. Biomechanical and clinical results are included as far as they have been available from an Internet search, publications,oral and poster presentations, and from companies directly. At the beginning anatomical, biomechanical, and clinical data of the natural facet joints are presented. Basic principles of the high morbidity in that topographical region and at the same time for an artificial replacement of the facet joints are derived from the data. An implant classification and the available results of these implants are the basis for this article, which presents the actual situation of the treatment method for motion retaining replacements of facet joints, which have been in general clinical use since 2005. Clinical studies are not yet finalized and there are not enough clinical data; therefore, no binding recommendations for treatment with artificial facet joints are possible.

Subjective and objective measures of physical activity in relationship to bone mineral content during late childhood: the Iowa Bone Development Study.

OBJECTIVE: This study compared accelerometry to self-report for the assessment of physical activity (PA) in relation to bone mineral content (BMC). In addition, we compared the ability of these measures to assess PA in boys versus girls. METHODS: Participants in this cross-sectional study included 449 children (mean age 11 years) from the Iowa Bone Development Study. PA was measured via 3-5 days of accelerometry using the Actigraph and 7 day self-report questionnaire using the Physical Activity Questionnaire for Children (PAQ-C). Hip, spine, and whole body BMC were measured via dual energy x ray absorptiometry (DXA). RESULTS: Partial correlation analysis (controlling for height, weight, and maturity) showed the Actigraph was significantly associated with hip (r = 0.40), spine (r = 0.20), and whole body (r = 0.33) BMC in boys, as was the PAQ-C (r = 0.28 hip, r = 0.19 spine, and r = 0.22 whole body). Among girls, only the Actigraph was significantly associated with hip (r = 0.18) and whole body (r = 0.16) BMC. Both the Actigraph and PAQ-C were significant in hip, spine, and whole body multivariable linear regression models (after controlling for body size and maturity) in boys. Only the Actigraph entered hip BMC regression model in girls. CONCLUSIONS: Our study supports previous work showing associations between everyday PA and BMC in older children. These associations are more likely to be detected with an objective versus subjective measure of PA, particularly in girls.

Heart rate monitoring of physical activity in children and adolescents: the Muscatine Study.

To assess the usefulness of whole-day heart rate monitoring as a quantitative measure of physical activity in children, the activity of 76 children and adolescents (ages 6 to 17 years), randomly selected from a school population, was measured during a typical summer day using a light-weight, nonrestrictive heart rate telemetry unit. A 12-hour recall and a simple self-rating of usual activity questionnaire were also administered on the same day. An additional 12-hour recall questionnaire was administered on another day. Within 1 month of the heart rate monitoring, the skinfold measures, peak aerobic capacity, and sexual maturation were assessed. Data analysis indicated that activity as measured by telemetry was related to questionnaire recall on the monitored day (r = .50), nonmonitored day (r = .32), and self-rating (r = .35); level of activity as measured by telemetry was related to peak aerobic capacity in girls (r = .36) but not in boys (r = -.06); body fat was related inversely to activity (r = -.32); and prepubescent children were more active than post- and pubescent children (P less than .003). No difference was found in activity level between boys and girls (P greater than .05). This study suggests that for children whole-day heart rate monitoring is an objective, nonobtrusive method for measuring physical activity; and maturation, but not gender, is an influential mediating factor for activity.

Validation of the CSA accelerometer for assessing children's physical activity.

The Computer Science Application (CSA) accelerometer is designed to detect the acceleration and deceleration of human movement. The purpose of this study was to evaluate its validity and utility for measuring children's activity in field settings. The criterion measure was heart rate telemetry. This study also examined the between-day stability of children's physical activity. Thirty-one children (7-15 yr) wore a CSA accelerometer and a heart rate telemetry monitor for 12 h.d-1 for 3 consecutive days. The validity correlation coefficients between accelerometry and heart rate telemetry for each monitored day ranged from r = 0.50-0.74. All children reported the accelerometer to be comfortable to wear. The moderate to high validity correlations and the subjects' favorable response to wearing the accelerometer support its validity and utility as an objective method for monitoring activity in children in field settings. However, the between-day stability of individual physical activity measures was low to moderate (r = -0.23 to 0.53), indicating that when using accelerometry or heart rate telemetry more than 3 d of monitoring is needed to assess usual activity.

The stability of children's physical activity as measured by accelerometry and self-report.

The Computer Science Application (CSA) accelerometer uses integrated circuitry and memory to provide a continuous recording of minute-by-minute movement counts. It has been previously validated as an objective monitor of children's physical activity in field and laboratory settings. Our purpose was to derive accelerometry summary variables reflective of different physical activity intensity levels, evaluate the stability of these summary variables, and define the number of days needed to adequately measure usual physical activity. A secondary study purpose was to compare three self-report questionnaires to accelerometry. Thirty children (7-15 yr) wore accelerometers for 12 h.d-1 for 6 d. Daily summary variables of average movement count (total physical activity) and daily frequency of sedentary through vigorous activity were constructed. Intraclass correlation coefficients (R) and 95% confidence intervals (CI) were used to analyze the data. Accelerometry stability using 1 monitored day to represent usual physical activity was R = 0.42-0.47. When 6 d were used, stability increased to R = 0.81-0.84. Acceptable intraclass correlations and CI were achieved with 4 d of monitoring (R = 0.75-0.78, CI = 0.60-0.88). The self-report questionnaires were poorly to moderately correlated to accelerometry variables (r = -0.03-0.51). Data indicate that in field settings: 1) accelerometry can be used to assess the intensity of children's activity and 2) 4 or more days of activity monitoring are needed to achieve satisfactory reliability.

Tracking physical fitness and physical activity from childhood to adolescence: the muscatine study.

PURPOSE: Physical fitness and physical activity tracking data enhance our understanding as to when children settle into their long-term exercise and fitness patterns and, therefore. provide insight as to when programs focusing on preventing sedentary adults behaviors should be initiated. METHODS: In this paper, the tracking of physical fitness and physical activity was examined in a 5-yr population-based study of children and adolescents in Muscatine, IA. Study subjects (N = 126) were pre- or early-pubescent at baseline (mean age boys 10.8 yr and girls 10.3 yr). Physical fitness was measured using direct determination of oxygen uptake and maximal voluntary isometric contraction while physical activity was assessed via questionnaire. RESULTS: Boys classified as sedentary based on initial measurements of TV viewing and video game playing were 2.2 times more likely than their peers to also be classified as sedentary at follow-up. Tracking of most physical fitness and physical activity variables was moderate to high, indicating some predictability of early measurements for later values. Sedentary behavior tracked better in boys, whereas vigorous activity tended to track better in girls. CONCLUSION: These observations suggest that preventive efforts focused on maintaining physical fitness and physical activity through puberty will have favorable health benefits in later years.

Predictors of left ventricular mass and resting blood pressure in children: the Muscatine Study.

The objective of this study was to determine predictors of left ventricular mass (LVM) and resting systolic blood pressure (SBP) in preteenage children. Subjects consisted of 124 children (7.9-12 yr) from Muscatine, Iowa. Methods consisted of echocardiographic examinations, random-zero SBP, hormone determination of serum androgens, physician's examination for Tanner stage, anthropometry, maximal bicycle ergometry, hand grip dynamometry, and a physical activity survey. Least square's regression analysis quantified the percentage of explained variability in LVM and resting SBP attributable to the predictor variables. All models were adjusted for body composition. In boys, 72% of the variability in LVM was explained by fat-free body mass (FFM), sum of skinfolds, and peak SBP. In girls, FFM and peak SBP explained 69% of the variability in LVM. Peak SBP was also a significant predictor of resting SBP in boys and girls. Study results indicated that physical fitness and physical activity are not significant predictors of LVM nor resting SBP; however, after adjusting for body composition, peak SBP was an independent predictor of LVM and resting SBP. This result suggests that peak SBP may aid in the prediction of subsequent hypertension and its complications such as left ventricular hypertrophy.

Longitudinal analysis of scaling VO2 for differences in body size during puberty: the Muscatine Study.

PURPOSE: The purpose of this study was to determine an appropriate method to "normalize" oxygen uptake (VO2) for body size in children and adolescents. METHODS: We examined allometric scaling factors for a cohort of 126 children (mean age at baseline = 10.3 yr) participating in a 5-yr follow-up study. Each year for 5 yr we measured peak VO2, submaximal VO2, body mass, height, body composition, and sexual maturation. We sorted the 5-yr data set by sexual maturation and gender and then used the generalized estimating equation method to estimate regression parameters that described the influence of log transformed body mass on log transformed VO2. All analyses were repeated using log transformed fat-free body mass (FFM) in lieu of log transformed body mass. RESULTS: Models using FFM appeared better at eliminating the effect of body size on VO2. In boys a univariate model with a FFM exponent of 0.91 and in girls a univariate model with a FFM exponent of 0.87 satisfactorily normalized peak VO2. However, we could not identify a common body size exponent for both boys and girls. CONCLUSIONS: Results support the use of allometric scaling of VO2 as a function of FFM for maturing boys and girls but indicate that the effects of maturation on the relationship between VO2 and body size differ between boys and girls.

Validity of near infrared body composition analysis in children and adolescents.

The purpose of this study was to evaluate the validity and reliability of the Futrex 5000A near infrared (NIR) spectrophotometer for the assessment of body composition in children and adolescents. Forty-eight subjects (24 boys and 24 girls) with a mean age of 12.7 +/- 2.7 yr underwent three methods of body composition testing: NIR, densitometry by hydrostatic weighing (HYDRO), and skinfold anthropometry (SKF). Percent body fat (%BF) and fat free mass (FFM) derived from the Lohman's age-adjusted Siri equation served as the criterion. Within session test-retest reliability was determined for the NIR device for all subjects and between-week reliability was evaluated for all test methods in 14 subjects. Based on the excellent within- and between-session reliability (ICC ranged from 0.907-0.999), the system offers the potential of obtaining longitudinal data in growth and development studies. However, the significant mean differences, moderate correlations with the criterion (r = 0.62-0.71) and inflated standard errors of estimate (SEE = 4.9-5.5% BF, 2.2-2.9 kg FFM) and total prediction errors (TE = 5.5-8.0% BF, 2.7-3.7 kg FFM) indicate that refinement of prediction equations is needed to establish the measurement validity. Continued research with expanded populations is needed to further demonstrate and evaluate the utility of this device.

Cross-validation of the Slaughter skinfold equations for children and adolescents.

Prior to sexual maturation, children and adolescents have more water and less bone mineral content than adults, resulting in less dense fat-free body mass (FFM). This suggests that previously established adult skinfold/density equations are inappropriate for use with children and adolescents for the prediction of body fatness (%BF) and FFM. To overcome this problem, Slaughter and colleagues have introduced new skinfold (SKF) equations that take into account the changing density of FFM in children and adolescents as they mature. The purpose of our study was to cross-validate a select set of the Slaughter SKF equations by comparing them with a criterion measurement (Lohman's Siri age-adjusted body density equation) in 122 subjects ranging in sexual maturation from pre- to post-pubescent and ranging in age from 8-17. Our cross-validation found very high intraclass (reliability) correlations (ICCs = 0.98-0.99) and high validity correlations (rs = 0.79-0.99). The standard errors of the estimate for %BF ranged from 3.5-4.6% and total errors for %BF ranged from 3.6-4.6%. The Slaughter equation using tricep and calf SKF for females was significantly different (P < 0.05) from the criterion measure in its prediction of %BF. In males, there was an interaction between the SKF equation and subject maturation level. The data indicate that the Slaughter SKF equations hold promise for estimating body composition in children and adolescents but are still in need of refinement.

A multicenter retrospective study of the clinical results of the LINK SB Charité intervertebral prosthesis. The initial European experience.

OBJECTIVE: This study is a multicenter, retrospective review of the initial clinical results of an artificial disc replacement, the LINK SB Charité intervertebral prosthesis. METHODS: Independent analysis by chart review included patient demographics, surgical data, and a comparison of presurgical to follow-up data. Data were analyzed from 93 patients (average age = 43.0 +/- 7.3) in whom a total of 139 Model III prostheses (Waldemar Link GmbH & Co, Hamburg, Germany) were implanted. RESULTS: The predominant diagnostic indication for the disc was degenerative disc disease (52.4%). The L4-L5 and L5-S1 levels comprised 87.1% of all levels implanted. The average follow-up was 11.5 +/- 8.4 months. After disc implantation, a significant proportion of the patient sample experienced pain relief (P < 0.05). Improvements were also noted in pain intensity, walking distance, lumbar mobility, and the percentage of patients showing a positive SLR or neurological weakness. No difference in work status after disc implantation could be detected. Device failure, migration, or dislocation occurred in 6 of 93 (6.5%) patients. CONCLUSIONS: This study represents the largest multicenter case series of any functional artificial disc implantation. Carefully controlled, prospective studies that compare disc implantation and fusion are warranted.

Noninvasive diagnosis of cruciate ligament damage with particular reference to computed tomography with arthrography.

Computed tomography (CT) with arthrography, a method not requiring anesthesia, has worked well in cruciate ligament damage diagnosis, particularly in the detection of PCL damage and in differentiation between ACL and PCL lesions. Evidence has been produced of its superior accuracy by comparison, in the study of 40 patients, among clinical findings, findings obtained from initial radiography, and diagnostic data produced by CT alone. Reference is also made to false interpretations in the context of clinical examination and CT.

Cross-validation of bioelectrical impedance analysis of body composition in children and adolescents.

BACKGROUND AND PURPOSE: The reliability and validity of measurements obtained with two bioelectrical impedance analyzers (BIAs), an RJL Systems model BIA-103 and a Berkeley Medical Research BMR-2000, were investigated using the manufacturers' prediction equations for the assessment of fat-free mass (FFM) (in kilograms) in children and adolescents. SUBJECTS: Forty-seven healthy children and adolescents (23 male, 24 female), ranging in age from 8 to 20 years (mean = 12.1, SD = 2.3), participated. METHODS: In the context of a repeated-measures design, the data were analyzed according to gender and maturation (Tanner staging). Hydrostatic weighing (HYDRO) and Lohman's Siri age-adjusted body density prediction equation served as the criteria for validating the BIA-obtained measurements. RESULTS: High intraclass correlation coefficients (ICC > or = .987) demonstrated good test-retest (between-week) measurement reliability for HYDRO and both BIA methods. Between-method (HYDRO versus BIA) correlation coefficients were high for both boys and girls (r > or = .97). The standard errors of estimate (SEEs) for FFM were slightly larger for boys than for girls and were consistently smaller for the RJL system than for the BMR system (RJL SEE = 1.8 kg for boys, 1.3 kg for girls; BMR SEE = 2.4 kg for boys, 1.9 kg for girls). The coefficients of determination were high for both BIA methods (r2 > or = .929). Total prediction errors (TEs) for FFM showed similar between-method trends (RJL TE = 2.1 kg for boys, 1.5 kg for girls; BMR TE = 4.4 kg for boys, 1.9 kg for girls). DISCUSSION AND CONCLUSION: This study demonstrated that the RJL BIA with the manufacturer's prediction equations can be used to reliably and accurately assess FFM in 8- to 20-year-old children and adolescents. The prediction of FFM by the BMR system was acceptable for girls, but significant overprediction of FFM for boys was noted.

[Acetabular component implantation in coxarthrosis due to dysplasia after high congenital hip dislocation]. / Zur Pfannenimplantation bei Dysplasiecoxarthrosen nach angeborener hoher Hüftluxation.

A total of 71 (25-110) months after primary total hip replacement, 17 patients with high congenital hip dislocation and false iliac acetabulum were clinically and radiologically assessed. Twenty-one threaded cups were placed, 16 at the site of the true acetabulum, one at the site of the acetabular rim and four at the site of the false acetabulum. The Harris hip score increased from 37.1 (20.2-55.5) points preoperatively to 84.7 (67.4-97.7) points postoperatively. Radiologically there were no signs of cup migration. It can be concluded that even complicated dysplastic hips can be treated successfully by total hip replacement, without prior ileofemoral distraction or additional acetabular augmentation.

Goal orientation and ratings of perceived exertion in graded exercise testing of adolescents.

This study examined the relationship between adolescents' goal orientation in sport and their ratings of perceived exertion (RPE) during a graded exercise test. Subjects (N = 114; 56 boys) were randomly selected adolescents (ages 11 to 15 years) who were part of a 5-year longitudinal study of cardiac growth. RPE was measured during each of three submaximal stages throughout the graded exercise test and again during the maximal stage. A series of regression analyses showed that RPE for female subjects was significantly predicted by Task Orientation, Perceived Ability, and Intensity of Leisure Activity at Stage 1, Task Orientation and Perceived Ability at Stage 2, and by Intensity of Leisure Activity at Stage 3. Examination of the beta weights indicated that lower RPE for the girls was related to higher Task Orientation and lower Perceived Ability and more experience with higher Intensity of Leisure Activity. Results are discussed in light of the literature pertaining to goal orientation and ratings of perceived exertion.

Effects of life-long fluoride intake on bone measures of adolescents: a prospective cohort study.

Controversy persists concerning the impact of community water fluoridation on bone health in adults, and few studies have assessed relationships with bone at younger ages. Ecological studies of fluoride's effects showed some increase in bone mineral density of adolescents and young adults in areas with fluoridated water compared with non-fluoridated areas. However, none had individual fluoride exposure measures. To avoid ecological fallacy and reduce bias, we assessed associations of average daily fluoride intake from birth to age 15 yr for Iowa Bone Development Study cohort members with age 15 yr dual-energy x-ray absorptiometry (DXA) bone outcomes (whole body, lumbar spine, and hip), controlling for known determinants (including daily calcium intake, average daily time spent in moderate-to-vigorous intensity physical activity, and physical maturity). Mean (SD) daily fluoride intake was 0.66 mg (0.24) for females and 0.78 mg (0.30) for males. We found no significant relationships between daily fluoride intake and adolescents' bone measures in adjusted models (for 183 females, all p values ≥ .10 and all partial R(2) ≤ 0.02; for 175 males, all p values ≥ .34 and all partial R(2) ≤ 0.01). The findings suggest that fluoride exposures at the typical levels for most US adolescents in fluoridated areas do not have significant effects on bone mineral measures.