D.L. Duren

Case Western Reserve University, Cleveland, Ohio, United States

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Publications (63)153.43 Total impact

  • Lower Extremity Review. 03/2014;
  • American Journal of Physical Anthropology 01/2014; 153:92-93. · 2.48 Impact Factor
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    ABSTRACT: This study examined relationships between excess body weight (EBW) loss and current gait and functional status in women 5 years after Roux-en-Y gastric bypass surgery. Gait data were analyzed in nine female bariatric patients for relationships with longitudinal changes in weight, body composition, and physical function assessed by the Short Musculoskeletal Functional Assessment (SMFA) questionnaire and the timed "get-up-and-go" (TGUG) test. Gait characteristics in the bariatric sample were also compared to an age- and BMI-matched nonsurgical reference sample from the Fels Longitudinal Study. Bariatric patients lost an average of 36.4 kg (61.1 %) of EBW between preoperative and 5-year follow-up visits (P < 0.01); SMFA function index scores and TGUG times also decreased (both P < 0.01). Degree of EBW loss was correlated with less time spent in initial double support and more time in single support (both P = 0.02), and for all gait variables, the bariatric sample fell within the 95 % confidence intervals of gait/EBW relationships in the reference sample. Gait and function 5 years after bariatric surgery were characteristic of current weight, not preoperative obesity, suggesting that substantial, sustained recovery of physical function is possible with rapid surgical weight loss.
    Obesity Surgery 09/2013; · 3.10 Impact Factor
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    ABSTRACT: Abstract Background: Evaluation of skeletal maturity provides clinicians and researchers a window into the developmental progress of the skeleton. The FELS method for maturity assessment provides a point estimate and standard error based on 98 skeletal indicators. Aim: This paper outlines the statistical methodology used by the original FELS method and evaluates improvements that address the following: serial correlation in the calibration sample is now considered, a Bayesian estimation method is now employed to improve estimation near ages 0 and 18 years and uncertainty in the calibration due to sampling is now accounted for when computing confidence limits. Subjects and methods: The original FELS method was calibrated using 677 Fels Longitudinal Study participants. In the improved method, serial correlation is accounted for using GEE, a Bayesian analysis with a prior centred on chronological age is used and the bootstrap is used to account for all sources of variation. Results: Accounting for serial correlation resulted in larger slopes for ordinal indicators. The Bayesian paradigm led to narrower confidence limits and a natural interpretation of skeletal age. Sampling variability in the calibration parameters was negligible. Conclusion: Improvements to the statistical basis of the FELS method provide a more effective method of estimating skeletal maturity.
    Annals of Human Biology 09/2013; · 1.48 Impact Factor
  • R.J. Sherwood, D.L. Duren
    01/2013: pages 306-320; Wiley-Blackwell.
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    ABSTRACT: Growth, development, and decline of the human skeleton are of central importance to physical anthropology. All processes of skeletal growth (longitudinal growth as well as gains and losses of bone mass) are subjected to environmental and genetic influences. These influences, and their relative contributions to the phenotype, can be asserted at any stage of life. We present here the gross phenotypic and genetic landscapes of four skeletal traits, and show how they vary across the life span. Phenotypic sex differences are found in bone diameter and cortical index (a ratio of cortical thickness over bone diameter) at a very early age and continue throughout most of life. Sexual dimorphism in summed cortical thickness and bone length, however, is not evident until shortly after the pubertal growth spurt. Genetic contributions (heritability) to these skeletal phenotypes are generally moderate to high. Bone length and bone diameter (which both scale with body size) tend to have the highest heritability, with heritability of bone length fairly stable across ages (with a notable dip in early childhood) and that of bone diameter peaking in early childhood. The bone traits summed cortical thickness and cortical index that may better reflect bone mass, a more plastic phenomenon, have slightly lower genetic influences, on average. Results from our phenotypic and genetic landscapes serve three key purposes: 1) demonstration of the integrated nature of the genetic and environmental underpinnings of skeletal form, 2) identification of periods of bone's relative sensitivity to genetic and environmental influences, 3) and stimulation of hypotheses predicting the effects of exposure to environmental variables on the skeleton, given variation in the underlying genetic architecture. Am J Phys Anthropol, 2013. © 2012 Wiley Periodicals, Inc.
    American Journal of Physical Anthropology 01/2013; 150(1):48-57. · 2.48 Impact Factor
  • 01/2013: pages -; Coimbra University Press.
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    ABSTRACT: Measures of maturity provide windows into the timing and tempo of childhood growth and maturation. Delayed maturation in a single child, or systemically in a population, can result from either genetic or environmental factors. In terms of the skeleton, delayed maturation may result in short stature or indicate another underlying issue. Thus, prediction of the timing of a maturational spurt is often desirable in order to determine the likelihood that a child will catch up to their chronological age peers. Serial data from the Fels Longitudinal Study were used to predict future skeletal age conditional on current skeletal age and to predict the timing of maturational spurts. For children who were delayed relative to their chronological age peers, the likelihood of catch-up maturation increased through the average age of onset of puberty and decreased prior to the average age of peak height velocity. For boys, the probability of an imminent maturational spurt was higher for those who were less mature. For girls aged 11 to 13 years, however, this probability was higher for those who were more mature, potentially indicating the presence of a skeletal maturation plateau between multiple spurts. The prediction model, available on the web, is most relevant to children of European ancestry living in the Midwestern US. Our model may also provide insight into the tempo of maturation for children in other populations, but must be applied with caution if those populations are known to have high burdens of environmental stressors not typical of the Midwestern US. Am J Phys Anthropol, 2013. © 2012 Wiley Periodicals, Inc.
    American Journal of Physical Anthropology 01/2013; 150(1):68-75. · 2.48 Impact Factor
  • Richard J Sherwood, Dana L Duren
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    ABSTRACT: Physical anthropological research was codified in the United States with the creation of the American Association of Physical Anthropology (AAPA) in 1929. That same year, a study began in yellow springs, Ohio, with a goal of identifying "what makes people different." The approach used to answer that question was to study the growth and development of Homo sapiens. The resulting study, the Fels Longitudinal Study, is currently the longest continuous study of human growth and development in the world. Although the AAPA and the Fels Longitudinal Study have existed as separate entities for more than 80 years now, it is not surprising, given the relationship between anatomical and developmental research, there has been considerable overlap between the two. As the field of physical anthropology has blossomed to include subdisciplines such as forensics, genetics, primatology, as well as sophisticated statistical methodologies, the importance of growth and development research has escalated. Although current Fels Longitudinal Study research is largely directed at biomedical questions, virtually all findings are relevant to physical anthropology, providing insights into basic biological processes and life history parameters. Some key milestones from the early years of the AAPA and the Fels Longitudinal Study are highlighted here that address growth and development research in physical anthropology. These are still held as fundamental concepts that underscore the importance of this line of inquiry, not only across the subdisciplines of physical anthropology, but also among anthropological, biological, and biomedical inquiries. Am J Phys Anthropol, 2013. © 2012 Wiley Periodicals, Inc.
    American Journal of Physical Anthropology 01/2013; 150(1):1-4. · 2.48 Impact Factor
  • American Journal of Physical Anthropology 01/2013; 150:253-253. · 2.48 Impact Factor
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    ABSTRACT: Walking gait is generally held to reach maturity, including walking at adult-like velocities, by 7-8 years of age. Lower limb length, however, is a major determinant of gait, and continues to increase until 13-15 years of age. This study used a sample from the Fels Longitudinal Study (ages 8-30 years) to test the hypothesis that walking with adult-like velocity on immature lower limbs results in the retention of immature gait characteristics during late childhood and early adolescence. There was no relationship between walking velocity and age in this sample, whereas the lower limb continued to grow, reaching maturity at 13.2 years in females and 15.6 years in males. Piecewise linear mixed models regression analysis revealed significant age-related trends in normalized cadence, initial double support time, single support time, base of support, and normalized step length in both sexes. Each trend reached its own, variable-specific age at maturity, after which the gait variables' relationships with age reached plateaus and did not differ significantly from zero. Offsets in ages at maturity occurred among the gait variables, and between the gait variables and lower limb length. The sexes also differed in their patterns of maturation. Generally, however, immature walkers of both sexes took more frequent and relatively longer steps than did mature walkers. These results support the hypothesis that maturational changes in gait accompany ongoing lower limb growth, with implications for diagnosing, preventing, and treating movement-related disorders and injuries during late childhood and early adolescence.
    Gait & posture 11/2012; · 2.58 Impact Factor
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    ABSTRACT: OBJECTIVE: Bariatric surgery is an effective method for acute weight loss. While the impact of bariatric surgery on general medical conditions (e.g., type 2 diabetes) is well documented, few studies focus on physical functional outcomes following weight-loss induced by bariatric surgery. DESIGN AND METHODS: We report on 50 women aged 20-74 scheduled for Roux-en-Y gastric bypass (RYGB) procedure who were enrolled for a prospective 1-year study. Height, weight, and waist circumference were recorded preoperatively and at 6 and 12 months, postoperatively. To track musculoskeletal/physical function changes, the timed-get-up-and-go (TGUG) and short-form health survey-36 (SF-36) and short musculoskeletal function assessment (SFMA) questionnaires were administered. RESULTS AND CONCLUSIONS: Patients had significant weight loss and functional improvement. At 1 year mean weight loss was 48.5 kg and mean TGUG improvement was 3.1 s. SMFA and SF-36 also showed improvement in functional components with weight loss at 6 months and 1-year post surgery. Significant associations were observed between TGUG and SMFA measures at all time points. Final weight at 1 year post bariatric surgery was also significantly correlated with most functional outcomes and changes in these outcomes. Partial correlations controlling for age revealed additional associations between body weight and functional outcomes, especially at the 6-month visit. Our results suggest that significant rapid weight loss, such as that attained by bariatric surgery, acutely improves musculoskeletal function in morbidly obese patients. Additionally, for patients with musculoskeletal disease or injury, weight loss resulting from bariatric surgery may serve as an adjunct for improving global functional outcome, and enhancing the rehabilitation potential.
    Obesity 11/2012; · 3.92 Impact Factor
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    ABSTRACT: Elucidating the somatic and maturational influences on the biomechanical properties of bone in children is crucial for a proper understanding of bone strength and quality in childhood and later life, and has significant potential for predicting adult fracture and osteoporosis risks. The ability of a long bone to resist bending and torsion is primarily a function of its cross-sectional geometric properties, and is negatively impacted by smaller external bone diameter. In pubescent girls, elevated levels of estrogen impede subperiosteal bone growth and increase endosteal bone deposition, resulting in bones averaging a smaller external and internal diameter relative to boys. In addition, given a well-documented secular trend for an earlier menarche, the age at which the rate of subperiosteal bone deposition decreases may also be younger in more recent cohorts of girls. In this study we examined the relationship between pubertal timing and subsequent bone strength in girls. Specifically, we investigated the effects of age at menarche on bone strength indicators (polar moment of inertia and section modulus) determined from cross-sectional geometry of the second metacarpal (MC2) using data derived from serial hand-wrist radiographs of female participants (N=223) in the Fels Longitudinal Study, with repeated measures of MC2 between the ages of 7 and 35 years. Using multivariate regression models, we evaluated the effects of age at menarche on associations between measures of bone strength in early adulthood and the same measures at a prepubertal age. Results indicate that later age at menarche is associated with stronger adult bone (in torsion and bending) when controlling for prepubertal bone strength (R(2) ranged between 0.54 and 0.70, p<0.001). Since cross-sectional properties of bone in childhood may have long lasting implications, they should be considered along with pubertal timing in assessing risk for future fracture and in clinical recommendations.
    Bone 04/2012; 51(1):38-45. · 4.46 Impact Factor
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    ABSTRACT: Quantitative ultrasound (QUS) traits are correlated with bone mineral density (BMD), but predict risk for future fracture independent of BMD. Only a few studies, however, have sought to identify specific genes influencing calcaneal QUS measures. The aim of this study was to conduct a genome-wide linkage scan to identify quantitative trait loci (QTL) influencing normal variation in QUS traits. QUS measures were collected from a total of 719 individuals (336 males and 383 females) from the Fels Longitudinal Study who have been genotyped and have at least one set of QUS measurements. Participants ranged in age from 18.0 to 96.6 years and were distributed across 110 nuclear and extended families. Using the Sahara ® bone sonometer, broadband ultrasound attenuation (BUA), speed of sound (SOS) and stiffness index (QUI) were collected from the right heel. Variance components based linkage analysis was performed on the three traits using 400 polymorphic short tandem repeat (STR) markers spaced approximately 10 cM apart across the autosomes to identify QTL influencing the QUS traits. Age, sex, and other significant covariates were simultaneously adjusted. Heritability estimates (h²) for the QUS traits ranged from 0.42 to 0.57. Significant evidence for a QTL influencing BUA was found on chromosome 11p15 near marker D11S902 (LOD = 3.11). Our results provide additional evidence for a QTL on chromosome 11p that harbors a potential candidate gene(s) related to BUA and bone metabolism.
    The Journal of Nutrition Health and Aging 01/2012; 16(1):8-13. · 2.39 Impact Factor
  • The Journal of frailty & aging. 01/2012; 1(2):50-51.
  • R.J. Sherwood, D.L. Duren
    01/2012: pages -; Springer.
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    ABSTRACT: Genes play an important role in lifelong skeletal health. Genes that influence bone building during childhood have the potential to affect bone health not only throughout childhood but also into adulthood. Given that peak bone mass is a significant predictor of adult fracture risk, it is imperative that the genetic underpinnings of the normal pediatric skeleton are uncovered. In a sample of 600 10-year-old children from 144 families in the Fels Longitudinal Study, we examined radiographic cortical bone measures of the second metacarpal. Morphometic measurements included bone width, medial and lateral cortical thicknesses, and the calculated cortical index representing the amount of cortex relative to bone width. We then conducted genome-wide linkage analysis on these traits in 440 genotyped individuals using the SOLAR analytic platform. Significant quantitative trait loci (QTL) were identified for bone traits on three separate chromosomes. A QTL for medial cortical thickness was localized to chromosome 2p25.2. A QTL for lateral cortical thickness was localized to chromosomal region 3p26.1-3p25.3. Finally, a QTL detected for cortical index was localized to the 17q21.2 chromosomal region. Each region contains plausible candidate genes for pediatric skeletal health, some of which confirm findings from studies of adulthood bone, and for others represent novel candidate genes for skeletal health.
    Bone 08/2011; 49(6):1213-8. · 4.46 Impact Factor
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    ABSTRACT: Some studies have shown a decline in blood pressure (BP) over the second half of the twentieth century. However, the increasing prevalence of obesity may have opposite effects on recent cohorts. Using serial BP data from the Fels Longitudinal Study, we examined secular trends in mean BP, the rate of change in BP with age (slopes), and the influence of obesity (i.e., BMI) and height on these trends during young-to-middle adulthood. The study sample consisted of 970 adults, aged 18-40 years, who were born between 1920 and 1979. Participants were grouped into birth decade cohorts and had up to 11 serial measurements of SBP, DBP, and BMI. Sex-stratified mixed longitudinal analyses were used to identify cohort effects on mean BP at ages 19, 29, and 39 years, and on the rate of change in BP with age. For both sexes, mean SBP did not vary significantly by birth cohort, before and after adjusting for height and BMI. Mean DBP exhibited a U-shaped secular trend even after adjusting for BMI and height that was influenced by age-by-cohort effects. By age 39 years, those born most recently had the highest mean DBP. There were cohort effects on the rate of change in DBP with age, but not on rate of SBP change. The most recent cohorts had higher rates of DBP change with age compared to the earlier cohorts. The secular trend was partially influenced by the trends in BMI.
    Journal of Hypertension 03/2011; 29(5):838-45. · 4.22 Impact Factor
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    ABSTRACT: The genetic architecture of the craniofacial complex has been the subject of intense scrutiny because of the high frequency of congenital malformations. Numerous animal models have been used to document the early development of the craniofacial complex, but few studies have focused directly on the genetic underpinnings of normal variation in the human craniofacial complex. This study examines 80 quantitative traits derived from lateral cephalographs of 981 participants in the Fels Longitudinal Study, Wright State University, Dayton, Ohio. Quantitative genetic analyses were conducted using the Sequential Oligogenic Linkage Analysis Routines analytic platform, a maximum-likelihood variance components method that incorporates all familial information for parameter estimation. Heritability estimates were significant and of moderate to high magnitude for all craniofacial traits. Additionally, significant quantitative trait loci (QTL) were identified for 10 traits from the three developmental components (basicranium, splanchnocranium, and neurocranium) of the craniofacial complex. These QTL were found on chromosomes 3, 6, 11, 12, and 14. This study of the genetic architecture of the craniofacial complex elucidates fundamental information of the genetic architecture of the craniofacial complex in humans.
    The Anatomical Record Advances in Integrative Anatomy and Evolutionary Biology 02/2011; 294(4):664-75. · 1.34 Impact Factor
  • American Journal of Physical Anthropology 01/2011; 144:222-223. · 2.48 Impact Factor

Publication Stats

201 Citations
153.43 Total Impact Points

Institutions

  • 2013
    • Case Western Reserve University
      Cleveland, Ohio, United States
  • 2006–2013
    • Wright State University
      • Department of Community Health
      Dayton, OH, United States
  • 2008
    • Concordia University–Ann Arbor
      Ann Arbor, Michigan, United States
  • 2002
    • University of Illinois at Chicago
      • Department of Oral Biology
      Chicago, IL, United States