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Scholarly Works (50 results)

  • Thesis
  • Peer Reviewed
UC San Diego Electronic Theses and Dissertations (2017)

Background: Falls are a common cause of morbidity among older adults. Although many fall risk factors are well understood, it is unknown whether a common geriatric condition, hyperkyphosis, increases fall risk.

Objectives: This dissertation research sought to determine whether older persons with worse degrees of kyphosis may be at increased risk of falls.

Methods: Three longitudinal cohorts of older adults (aged ≥65) were used, each with different kyphosis measures, to examine the association between degree of kyphosis and fall risk. Study 1 examined whether four measures of kyphosis (Debrunner kyphometer, flexicurve ruler, Cobb angle, and block method) increased the odds of an incident fall over one year of monthly falls follow-up in a mixed-gender sample of 72 individuals (mean age=78). Studies 2 and 3 each prospectively examined two different measures of kyphosis and incident falls over three years of tri-annual follow-up through multivariable modeling with GEEs. Study 2 included 2,346 men with the Cobb angle measure of kyphosis (mean age=74) and 2,929 men with block-measured kyphosis (mean age=79) from the Osteoporotic Fractures in Men Study (MrOS). Study 3 used data from 1,162 women with the Cobb angle measure (mean age=69) and 610 women with the flexicurve measure of kyphosis (mean age=73) from the Study of Osteoporotic Fractures in Women (SOF).

Results: In Study 1, all four measures of kyphosis conferred a 2-3 fold increase per SD in the odds of a fall over the following year (64% of participants fell over one year). In Studies 2 and 3, Cobb angle was not associated with fall risk in either MrOS or SOF. The blocks method was predictive of fall risk in MrOS (RR=1.11 per SD; 95% CI=1.06, 1.17) and KI was predictive of fall risk in SOF (RR=1.22 per SD; 95% CI=1.07, 1.40).

Conclusion: All three studies provide evidence that increased kyphosis predicts greater fall risk in older persons. The Cobb angle measure, however, appears to be least related to falls, possibly because it is a measure limited to the mid to lower thoracic spine whereas the block and flexicurve methods include curvature in the lower cervical and entire thoracic spine.

    Cover page: Hyperkyphosis and incident falls among community-dwelling older adults
    • Article
    • Peer Reviewed
    UC Davis Previously Published Works (2014)

    Background

    The prevalence of hyperkyphosis is increased in older men; however, risk factors other than age and vertebral fractures are not well established. We previously reported that poor paraspinal muscle composition contributes to more severe kyphosis in a cohort of both older men and women.

    Methods

    To specifically evaluate this association in older men, we conducted a cross-sectional study to evaluate the association of paraspinal muscle composition and degree of thoracic kyphosis in an analytic cohort of 475 randomly selected participants from the Osteoporotic Fractures in Men (MrOS) study with baseline abdominal quantitative computed tomography (QCT) scans and plain thoracic radiographs. Baseline abdominal QCT scans were used to obtain abdominal body composition measurements of paraspinal muscle and adipose tissue distribution. Supine lateral spine radiographs were used to measure Cobb angle of kyphosis. We examined the linear association of muscle volume, fat volume and kyphosis using loess plots. Multivariate linear models were used to investigate the association between muscle and kyphosis using total muscle volume, as well as individual components of the total muscle volume, including adipose and muscle compartments alone, controlling for age, height, vertebral fractures, and total hip bone mineral density (BMD). We examined these associations among those with no prevalent vertebral fracture and those with BMI < 30 kg/m2.

    Results

    Among men in the analytic cohort, means (SD) were 74 (SD = 5.9) years for age, and 37.5 (SD = 11.9) degrees for Cobb angle of kyphosis. Men in the lowest tertile of total paraspinal muscle volume had greater mean Cobb angle than men in the highest tertile, although test of linear trend across tertiles did not reach statistical significance. Neither lower paraspinal skeletal muscle volume (p-trend = 0.08), or IMAT (p-trend = 0.96) was associated with greater kyphosis. Results were similar among those with no prevalent vertebral fractures. However, among men with BMI < 30 kg/m2, those in the lowest tertile of paraspinal muscle volume had greater adjusted mean kyphosis (40.0, 95% CI: 37.8 - 42.1) compared to the highest tertile (36.3, 95% CI: 34.2 - 38.4).

    Conclusions

    These results suggest that differences in body composition may potentially influence kyphosis.
      Cover page: Kyphosis and paraspinal muscle composition in older men: a cross-sectional study for the osteoporotic fractures in men (MrOS) research group
      • Article
      • Peer Reviewed
      UC Davis Previously Published Works (2022)

      Background

      Approximately 30% to 40% of older adults have hyperkyphosis, defined as excessive curvature of the thoracic spine. Hyperkyphosis is associated with increased morbidity and mortality. This study aimed to determine whether hyperkyphosis (Cobb's angle) and upper extremity tasks were independently associated with the 6-min walk test (6MWT) in community-dwelling older adults with hyperkyphosis.

      Methods

      In this cross-sectional study, we studied 71 women and 28 men aged 60-87 from the study of hyperkyphosis, exercise, and function trial (SHEAF) who had kyphosis, 3 timed upper extremity tasks and the 6MWT assessed at their baseline visit. We used standing lateral spine radiographs and a standardized protocol for thoracic kyphosis (T4-T12) to measure Cobb angle of kyphosis. In addition, 3 activity of daily living (ADL) extremity tests (putting on and removing a laboratory coat, picking up a penny from the floor, and lifting a 7-lb. book to a shelf) were used.

      Results

      The mean ± SD age was 70.1 ± 6.1 years. The mean ± SD Cobb angle of kyphosis was 57.4 ± 12.5 degrees. On average ± SD, the participants walked 504.8 ± 84.2 m in 6 min and took 2.4 ± 2.2 prescription medications. The mean ± SD height was 164.7 ± 8.5 cm, weight was 68.7 ± 13.1 kg, and BMI was 25.2 ± 4.0 kg/m2. Multivariate regression revealed that age, height, upper extremity book lift task, and the number of prescribed medications were significant predictors of performance on the 6MWT (p < 0.05).

      Conclusions

      While kyphosis was not associated with the 6MWT, timed tests of upper extremity function indicated that upper body dynamics can affect walking performance. In addition, sociodemographic factors and the number of prescribed medications were significant contributing factors to the 6MWT in older adults with mild to moderate hyperkyphosis. These results illustrate multifactorial influences on physical performance and the need for an integrated and targeted approach in helping older hyperkyphotic adults maintain healthy physical functioning as they age.
        Cover page: Slower upper extremity function in older adults with hyperkyphosis negatively impacts the 6-min walk test
        • Article
        • Peer Reviewed
        UC San Diego Previously Published Works (2020)
        Proper function of the female pelvic floor requires intact pelvic floor muscles (PFMs). The prevalence of pelvic floor disorders (PFDs) increases substantially with age, in part due to clinically identified deterioration of PFM function with age. However, the etiology of this decline remains largely unknown. We previously demonstrated that PFMs undergo age-related fibrotic changes. This study sought to determine whether aging also impacts PFMs' passive mechanical properties that are largely determined by the intramuscular extracellular matrix. Biopsies from younger (≤52y) and older (>52y) female cadaveric donors were procured from PFMs, specifically coccygeus (C) and two portions of the levator ani - iliococcygeus (IC) and pubovisceralis (PV), and the appendicular muscles - obturator internus (OI) and vastus lateralis (VL). Muscle bundles were subjected to a passive loading protocol, and stress-sarcomere length (Ls) relationships calculated. Muscle stiffness was compared between groups using 2-way ANOVA and Sidak pairwise comparisons, α < 0.05. The mean age was 43.4 ± 11.6y and 74.9 ± 11.9y in younger (N = 5) and older (N = 10) donors, respectively. In all PFMs, the quadratic coefficient of parabolic regression of the stress-Ls curve, a measure of stiffness, was lower in the younger versus older group: C: 33.7 ± 13.9 vs 87.2 ± 10.7, P = 0.02; IC: 38.3 ± 12.7 vs 84.5 ± 13.9, P = 0.04; PV: 24.7 ± 8.8 vs 74.6 ± 9.6, P = 0.04. In contrast, non-PFM stiffness was not affected by aging: OI: 14.5 ± 4.7 vs 32.9 ± 6.2, P = 0.8 and VL: 13.6 ± 5.7 vs 30.1 ± 5.3, P = 0.9. Age-associated increase in PFM stiffness is predicted to negatively impact PFM function by diminishing muscle load-bearing, excursional, contractile, and regenerative capacity, thus predisposing older women to PFDs.
          Cover page: Age-associated changes in the mechanical properties of human cadaveric pelvic floor muscles.
          • Article
          • Peer Reviewed
          UC Davis Previously Published Works (2013)

          Background

          Maintaining physical function is an important prerequisite for preserving independence in later life. Greater degrees of kyphosis in the thoracic spine are prevalent in older persons and accompanied by reduced physical function in multiple cross-sectional studies. It is unknown whether kyphosis predicts worse physical function over time.

          Methods

          We retrospectively assessed whether greater magnitude of kyphosis is associated with decline in self-reported and objectively measured physical function over 15 years. Digitized Cobb angle kyphosis (T4-T12) was derived from supine lateral thoracic spine radiographs in a cohort of 1,196 women aged 65 and older (mean = 69.3 years [SD = 4.0]). Using regression models, we evaluated associations of baseline kyphosis with both self-reported functional status and objectively measured gait speed, grip strength, and timed chair stands cross-sectionally and as change assessed over 15 years.

          Results

          In cross-sectional multivariate analyses, with each 10-degree increment of kyphosis, grip strength was 0.24 kg lower (p = .02), but there were no significant associations between kyphosis and functional status, gait speed, or timed chair stand, likely reflecting the high functioning study participants. In multivariate longitudinal analysis, with each 10-degree increment in baseline kyphosis, there was 0.07 point additional decline in functional status (p = .09), 0.01 m/s more decline in gait speed (p = .07), and 0.32 s greater decline in time to complete five chair stands (p = .004), but no association with decline in grip strength.

          Conclusions

          Greater magnitude of kyphosis may predict worsening lower extremity function over time in older women. Early recognition and preventative measures against kyphosis progression may help preserve physical function over the long term.
            Cover page: Kyphosis and Decline in Physical Function Over 15 Years in Older Community-Dwelling Women: The Study of Osteoporotic Fractures
            • Article
            • Peer Reviewed
            UC San Diego Previously Published Works (2021)
            Age-related pelvic floor muscle (PFM) dysfunction is a critical defect in the progression to pelvic floor disorders (PFDs). Despite dramatic prevalence of PFDs in older women, the underlying pathophysiology of age-related PFM dysfunction remains poorly understood. Using cadaveric specimens, we quantified aging effects on functionally relevant PFM properties and compared PFMs with the appendicular muscles from the same donors. PFMs, obturator internus, and vastus lateralis were procured from younger (N = 4) and older (N = 11) donors with known obstetrical and medical history. Our findings demonstrate that PFMs undergo degenerative, rather than atrophic, alterations. Importantly, age-related fibrotic degeneration disproportionally impacts PFMs compared to the appendicular muscles. We identified intramuscular lipid accumulation as another contributing factor to the pathological alterations of PFMs with aging. We observed a fourfold decrease in muscle stem cell (MuSC) pool of aged relative to younger PFMs, but the MuSC pool of appendicular muscles from the same older donors was only twofold lower than in younger group, although these differences were not statistically significant. Age-related degeneration appears to disproportionally impact PFMs relative to the appendicular muscles from the same donors. Knowledge of tissue- and cell-level changes in aged PFMs is essential to promote our understanding of the mechanisms governing PFM dysfunction in older women.
              Cover page: Quantifying the Effects of Aging on Morphological and Cellular Properties of Human Female Pelvic Floor Muscles
              • Article
              • Peer Reviewed
              UC San Diego Previously Published Works (2019)
              Breast cancer is the most common cancer of women in the United States. It is also proving to be one of the most treatable. Early detection, surgical intervention, therapeutic radiation, cytotoxic chemotherapies and molecularly targeted agents are transforming the lives of patients with breast cancer, markedly improving their survival. Although current breast cancer treatments are largely successful in producing cancer remission and extending lifespan, there is concern that these treatments may have long lasting detrimental effects on cancer survivors, in part, through their impact on non-tumor cells. Presently, the impact of breast cancer treatment on normal cells, its impact on cellular function and its effect on the overall function of the individual are incompletely understood. In particular, it is unclear whether breast cancer and/or its treatments are associated with an accelerated aging phenotype. In this review, we consider breast cancer survivorship from the perspective of accelerated aging, and discuss the evidence suggesting that women treated for breast cancer may suffer from an increased rate of physical and cognitive decline that likely corresponds with underlying vulnerabilities of genome instability, epigenetic changes, and cellular senescence.
                Cover page: Breast cancer treatment and its effects on aging
                • Article
                • Peer Reviewed
                UC Davis Previously Published Works (2016)

                Background

                Hyperkyphosis negatively affects health status, physical mobility, and quality of life, but there is no standard protocol for treating people with hyperkyphosis. Treatment options include targeted exercise.

                Objectives

                This single-site randomized controlled trial (RCT) will determine the efficacy of a targeted multimodal spine-strengthening exercise program, compared with no exercise intervention, among community-dwelling men and women aged ≥60 years.

                Design

                The RCT is a parallel-group design, with 1:1 randomization to exercise and attentional control groups.

                Setting

                The study will be conducted at one primary site (one academic medical center partnered with one local community medical center).

                Participants

                One hundred men and women, aged ≥60 years, with thoracic kyphosis ≥40 degrees will be randomized.

                Intervention

                The targeted multimodal spine-strengthening exercise intervention includes exercise and postural training delivered by a physical therapist in a group of 10 participants, 3 times a week for 6 months. Controls receive monthly health education meetings in a group of 10 participants and monthly calls from the study coordinator to monitor physical activity and any adverse events.

                Measurements

                The primary outcome is change in Cobb angle of kyphosis measured from lateral spine radiographs at baseline and 6 months. Secondary outcomes include change in physical function (assessed with the modified Physical Performance Test, Timed "Up & Go" Test, timed loaded standing, 4-m walk, and Six-Minute Walk Test) and health-related quality of life (assessed with the modified Scoliosis Research Society instrument [SRS-30] self-image domain and Patient Reported Outcomes Measurement Information System [PROMIS] global health and physical function indexes). Additional secondary outcomes include pain, physical activity level, spinal flexion and extension muscle strength, paraspinal extensor muscle density, and adverse events.

                Limitations

                Blinding of the participants and instructors providing the intervention is not possible.

                Conclusions

                The efficacy of a high-quality, adequately powered exercise intervention in men and women with kyphosis ≥40 degrees will be evaluated to determine whether targeted multimodal spine-strengthening exercise reduces hyperkyphosis in older adults and improves important secondary outcomes of physical function and health-related quality of life.
                  Cover page: Study of Hyperkyphosis, Exercise and Function (SHEAF) Protocol of a Randomized Controlled Trial of Multimodal Spine-Strengthening Exercise in Older Adults With Hyperkyphosis
                  • Article
                  • Peer Reviewed
                  UC San Diego Previously Published Works (2020)

                  Objectives

                  Hyperkyphosis is associated with restricted pulmonary function and posture, potentially contributing to poor sleep. A previous study reported older women with hyperkyphosis had worse self-reported sleep quality, but it is less clear if this association exists in men. We examined the association between hyperkyphosis and subjective and objective sleep quality in a cohort of older men.

                  Design

                  Longitudinal analysis of data from large cohort of older men participating in the Osteoporotic Fractures in Men Study (MrOS).

                  Setting

                  Community.

                  Participants

                  We studied 754 men participants in MrOS who had kyphosis measured during the 3rd clinic visit (2007-2009) and future subjective and objective sleep quality assessed between 2009-2012 (an average of 2.9 years later).

                  Intervention

                  N/A.

                  Measurements

                  To measure kyphosis, 1.7 cm thick wooden blocks were placed under the participant's head to achieve a neutral spine position while lying supine on a DXA table. We collected data on both subjective (Pittsburgh Sleep Quality Index [PSQI], and Epworth Sleepiness Scale [ESS]) and objective (wrist actigraphy: Total Sleep Time [TST], Wake After Sleep Onset [WASO], Sleep Efficiency [SE], Sleep Onset Latency [SOL]; and polysomnography: Apnea Hypopnea Index [AHI]) sleep measurements. Those who required >3 blocks were considered hyperkyphotic (n = 145 or 19.2%).

                  Results

                  In unadjusted and multivariable analyses, men with hyperkyphosis did not report having worse self-reported sleep characteristics based on PSQI and ESS. Similarly, there were no significant associations between hyperkyphosis and objective sleep measures. When examined as a continuous predictor (blocks ranging from 0-8), results were no different.

                  Conclusions

                  Although we hypothesized that poor posture in those with hyperkyphosis would interfere with sleep, in this sample of older men, worse kyphosis was not associated with self-reported or objectively measured poor sleep quality.
                    Cover page: Hyperkyphosis and self-reported and objectively measured sleep quality in older men
                    • Article
                    • Peer Reviewed
                    UC San Diego Previously Published Works (2013)
                    Age-related hyperkyphosis is thought to be a result of underlying vertebral fractures, but studies suggest that among the most hyperkyphotic women, only one in three have underlying radiographic vertebral fractures. Although commonly observed, there is no widely accepted definition of hyperkyphosis in older persons, and other than vertebral fracture, no major causes have been identified. To identify important correlates of kyphosis and risk factors for its progression over time, we conducted a 15-year retrospective cohort study of 1196 women, aged 65 years and older at baseline (1986 to 1988), from four communities across the United States: Baltimore County, MD; Minneapolis, MN; Portland, OR; and the Monongahela Valley, PA. Cobb angle kyphosis was measured from radiographs obtained at baseline and an average of 3.7 and 15 years later. Repeated measures, mixed effects analyses were performed. At baseline, the mean kyphosis angle was 44.7 degrees (SE = 0.4, SD = 11.9) and significant correlates included a family history of hyperkyphosis, prevalent vertebral fracture, low bone mineral density, greater body weight, degenerative disc disease, and smoking. Over an average of 15 years, the mean increase in kyphosis was 7.1 degrees (SE = 0.25). Independent determinants of greater kyphosis progression were prevalent and incident vertebral fractures, low bone mineral density and concurrent bone density loss, low body weight, and concurrent weight loss. Thus, age-related kyphosis progression may be best prevented by slowing bone density loss and avoiding weight loss.
                      Cover page: Factors associated with kyphosis progression in older women: 15 years' experience in the study of osteoporotic fractures
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