Browsing by Author "Koh, Victoria"

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    Future requirements for and supply of ophthalmologists for an aging population in Singapore.
    (Hum Resour Health, 2015-11-17) Ansah, John P; De Korne, Dirk; Bayer, Steffen; Pan, Chong; Jayabaskar, Thiyagarajan; Matchar, David B; Lew, Nicola; Phua, Andrew; Koh, Victoria; Lamoureux, Ecosse; Quek, Desmond
    BACKGROUND: Singapore's population, as that of many other countries, is aging; this is likely to lead to an increase in eye diseases and the demand for eye care. Since ophthalmologist training is long and expensive, early planning is essential. This paper forecasts workforce and training requirements for Singapore up to the year 2040 under several plausible future scenarios. METHODS: The Singapore Eye Care Workforce Model was created as a continuous time compartment model with explicit workforce stocks using system dynamics. The model has three modules: prevalence of eye disease, demand, and workforce requirements. The model is used to simulate the prevalence of eye diseases, patient visits, and workforce requirements for the public sector under different scenarios in order to determine training requirements. RESULTS: Four scenarios were constructed. Under the baseline business-as-usual scenario, the required number of ophthalmologists is projected to increase by 117% from 2015 to 2040. Under the current policy scenario (assuming an increase of service uptake due to increased awareness, availability, and accessibility of eye care services), the increase will be 175%, while under the new model of care scenario (considering the additional effect of providing some services by non-ophthalmologists) the increase will only be 150%. The moderated workload scenario (assuming in addition a reduction of the clinical workload) projects an increase in the required number of ophthalmologists of 192% by 2040. Considering the uncertainties in the projected demand for eye care services, under the business-as-usual scenario, a residency intake of 8-22 residents per year is required, 17-21 under the current policy scenario, 14-18 under the new model of care scenario, and, under the moderated workload scenario, an intake of 18-23 residents per year is required. CONCLUSIONS: The results show that under all scenarios considered, Singapore's aging and growing population will result in an almost doubling of the number of Singaporeans with eye conditions, a significant increase in public sector eye care demand and, consequently, a greater requirement for ophthalmologists.
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    Projection of Eye Disease Burden in Singapore.
    (Annals of the Academy of Medicine, Singapore, 2018-01) Ansah, John P; Koh, Victoria; de Korne, Dirk F; Bayer, Steffen; Pan, Chong; Thiyagarajan, Jayabaskar; Matchar, David B; Lamoureux, Ecosse; Quek, Desmond

    Introduction

    Singapore's ageing population is likely to see an increase in chronic eye conditions in the future. This study aimed to estimate the burden of eye diseases among resident Singaporeans stratified for age and ethnicity by 2040.

    Materials and methods

    Prevalence data on myopia, epiretinal membrane (ERM), retinal vein occlusion (RVO), age macular degeneration (AMD), diabetic retinopathy (DR), cataract, glaucoma and refractive error (RE) by age cohorts and educational attainment from the Singapore Epidemiology of Eye Diseases (SEED) study were applied to population estimates from the Singapore population model.

    Results

    All eye conditions are projected to increase by 2040. Myopia and RE will remain the most prevalent condition, at 2.393 million (2.32 to 2.41 million) cases, representing a 58% increase from 2015. It is followed by cataract and ERM, with 1.33 million (1.31 to 1.35 million), representing an 81% increase, and 0.54 million (0.53 to 0.549 million) cases representing a 97% increase, respectively. Eye conditions that will see the greatest increase from 2015 to 2040 in the Chinese are: DR (112%), glaucoma (100%) and ERM (91.4%). For Malays, DR (154%), ERM (136%), and cataract (122%) cases are expected to increase the most while for Indians, ERM (112%), AMD (101%), and cataract (87%) are estimated to increase the most in the same period.

    Conclusion

    Results indicate that the burden for all eye diseases is expected to increase significantly into the future, but at different rates. These projections can facilitate the planning efforts of both policymakers and healthcare providers in the development and provision of infrastructure and resources to adequately meet the eye care needs of the population. By stratifying for age and ethnicity, high risk groups may be identified and targeted interventions may be implemented.
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    Systems modelling as an approach for understanding and building consensus on non-communicable diseases (NCD) management in Cambodia.
    (BMC health services research, 2019-01-03) Ansah, John P; Islam, Amina Mahmood; Koh, Victoria; Ly, Vanthy; Kol, Hero; Matchar, David B; Loun, Chhun; Loun, Mondol

    Background

    This paper aims to demonstrate how systems modeling methodology of Group Model Building (GMD) can be applied for exploring and reaching consensus on non-communicable disease (NCD) management. This exercise was undertaken as a first step for developing a quantitative simulation model for generating credible estimates to make an investment case for the prevention and management of NCDs.

    Methods

    Stakeholder engagement was facilitated through the use of a Group Model Building (GMB) approach. This approach combines various techniques in order to gain a whole system perspective.

    Results

    A conceptual qualitative model framework that connects prevention-via risk factors reduction-screening and treatment of non-communicable diseases (NCDs) was developed with stakeholders that draws on stakeholders personal experiences, beliefs, and perceptions through a moderated interactions to gain in-depth understanding of NCDs management.

    Conclusion

    Managing NCDs in Cambodia will require concerted effort to tackle NCD risk factors, identifying individuals with NCDs through screening and providing adequate and affordable consistent care to improve health and outcomes of NCDs.
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    Trajectories of functional ability over the life course: a conceptual model of the interaction of stressor-induced functional loss and resilience.
    (System dynamics review, 2018-10) Matchar, David B; Ansah, John P; Koh, Victoria; Whitson, Heather E
    Understanding the factors that influence functional ability over the life course is integral to identifying clinical and public health policies to facilitate successful aging. The World Health Organization has advocated a conceptual framework to clarify the policy discussion. We have sought to translate this general framework into an explicit system dynamics model of the interaction of physiological loss, stressors and endogenous responses to produce a familiar variety of trajectories of functional ability over the life courses. Simulation experiments were implemented for both a 30-month duration with only one major stressor; and for the life course with an initial major stressor and subsequent stressors determined by the level of functional ability. For both contexts, variations in the few parameters in the scenarios led to a realistic range of trajectories of function over time.
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    Vitamin D Levels and the Risk of Cognitive Decline in Chinese Elderly People: the Chinese Longitudinal Healthy Longevity Survey.
    (The journals of gerontology. Series A, Biological sciences and medical sciences, 2016-10) Matchar, David B; Chei, Choy-Lye; Yin, Zhao-Xue; Koh, Victoria; Chakraborty, Bibhas; Shi, Xiao-Ming; Zeng, Yi

    Background

    Vitamin D has a neuroprotective function, potentially important for the prevention of cognitive decline. Prospective studies from Western countries support an association between lower vitamin D level and future cognitive decline in elderly people. No prospective study has examined this association in Asia.

    Methods

    This community-based cohort study of elderly people in China follows 1,202 cognitively intact adults aged ≥60 years for a mean duration of 2 years. Plasma vitamin D level was measured at the baseline. Cognitive state of participants was assessed using the Mini-Mental State Examination (MMSE). Cognitive impairment was defined as an MMSE score <18. Cognitive decline was defined as ≥3 points decline from baseline. Multivariable logistic regression models were used to examine the association between quartiles of vitamin D levels with cognitive decline and incidence of cognitive impairment.

    Results

    Participants with low vitamin D level had an increased risk of cognitive decline. Compared with the highest quartile of vitamin D levels, the multivariable odds ratios (ORs; 95% confidence interval) for cognitive decline were 2.1 (1.3-3.4) for the second highest quartile, 2.2 (1.4-3.6) for the third highest quartile, and 2.0 (1.2-3.3) for the lowest quartile. The multivariable ORs of incident cognitive impairment for the second highest, third highest, and lowest versus highest quartiles of vitamin D levels were 1.9 (0.9-4.1), 2.6 (1.2-5.6), and 3.2 (1.5-6.6), respectively.

    Conclusions

    This first follow-up study of elderly people, including the oldest-old, in Asia shows that low vitamin D levels were associated with increased risk of subsequent cognitive decline and impairment.