Vivian Isaac

Dr. Vivian Isaac

orcid

Research Focus & Metrics

Academic Career Length

18Years (2009-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2011 in Frontiers in Aging Neuroscience
Verified
Journal Article
Open access
VIVivian Isaac
Vivian Isaac
SSSam Sim
Sam Sim
HZHui Zheng
Hui Zheng
VZVitali Zagorodnov
Vitali Zagorodnov
ETE Shyong Tai
E Shyong Tai
MCMichael W. L. Chee
Michael W. L. Chee
The link between central adiposity and cognition has been established by indirect measures such as body mass index (BMI) or waist–hip ratio. Magnetic resonance imaging (MRI) quantification of central abdominal fat has been linked to elevated risk of cardiovascular and cerebro-vascular disease. However it is not known how quantification of visceral fat correlates with cognitive performance and measures of brain structure. We filled this gap by characterizing the relationships between MRI measures of abdominal adiposity, brain morphometry, and cognition, in healthy elderly. Methods: A total of 184 healthy community dwelling elderly subjects without cognitive impairment participated in this study. Anthropometric and biochemical markers of cardiovascular risk, neuropsychological measurements as well as MRI of the brain and abdomen fat were obtained. Abdominal images were segmented into subcutaneous adipose tissue and visceral adipose tissue (VAT) adipose tissue compartments. Brain MRI measures were analyzed quantitatively to determine total brain volume, hippocampal volume, ventricular volume, and cortical thickness. Results: VAT showed negative association with verbal memory (r = 0.21, p = 0.005) and attention (r = 0.18, p = 0.01). Higher VAT was associated with lower hippocampal volume (F = 5.39, p = 0.02) and larger ventricular volume (F = 6.07, p = 0.02). The participants in the upper quartile of VAT had the lowest hippocampal volume even after adjusting for age, gender, hypertension, and BMI (b = −0.28, p = 0.005). There was a significant age by VAT interaction for cortical thickness in the left prefrontal region. Conclusion: In healthy older adults, elevated VAT is associated with negative effects on cognition, and brain morphometry.

1 August 2009 in The American Journal of Geriatric Psychiatry
Verified
Journal Article
Closed access
VIVivian Isaac
Vivian Isaac
RSRobert Stewart
Robert Stewart
SASylvaine Artero
Sylvaine Artero
MAMarie-Laure Ancelin
Marie-Laure Ancelin
KRKaren Ritchie
Karen Ritchie

1 June 2016 in Medicine
Verified
Journal Article
Open access
VIVivian Isaac
Vivian Isaac
CWChia-Yi Jenny Wu
Chia-Yi Jenny Wu
CHChun-Ta Huang
Chun-Ta Huang
BBBernhard T. Baune
Bernhard T. Baune
CTChia-Lin Tseng
Chia-Lin Tseng
CMCraig S. McLachlan
Craig S. McLachlan
Neutrophil to lymphocyte ratio (NLR) is an easy measurable laboratory marker used to evaluate systemic inflammation. Elevated NLR is associated with poor survival and increased morbidity in cancer and cardiovascular disease. However, the usefulness of NLR to predict morbidity and mortality in a hospital setting for patients with multiple chronic conditions has not been previously examined. In this study, we investigate the association between NLR and mortality in multimorbid medical inpatients. Two hundred thirty medical in-patients with chronic conditions were selected from a single academic medical center in Taiwan. Retrospective NLRs were calculated from routine full blood counts previously obtained during the initial hospital admission and at the time of discharge. Self-rated health (using a single-item question), medical disorders, depressive symptoms, and medical service utilization over a 1-year period were included in the analyses. Mortality outcomes were ascertained by reviewing electronic medical records and follow-up. The mortality rate at 2-year follow-up was 23%. Depression (odds ratio [OR] 1.9 [95% CI 1.0-3.7]), poor self-rated health (OR 2.1 [95% CI 1.1-3.9]), being hospitalized 2 or more times in the previous year (OR 2.3 [95% CI 1.2-4.6]), metastatic cancer (OR 4.7 [95% CI 2.3-9.7]), and chronic liver disease (OR 4.3 [95% CI 1.5-12.1]) were associated with 2-year mortality. The median (interquartile range) NLR at admission and discharge were 4.47 (2.4-8.7) and 3.65 (2.1-6.5), respectively. Two-year mortality rates were higher in patients with an elevated NLR at admission (NLR 3 = 27.6%) and discharge (NLR < 3 = 14.7%, NLR >3 = 29.1%). Multivariate logistic regression demonstrated that an elevated NLR >3.0 at admission (OR 2.3 [95% CI 1.0-5.2]) and discharge (OR 2.3 [95% CI 1.1-5.0]) were associated with mortality independent of baseline age, sex, education, metastatic cancer, liver disease, depression, and previous hospitalization. Increased NLR is associated with mortality among medical inpatients with multiple chronic conditions. NLR may provide added value to predict both risk of mortality for the inpatients with chronic conditions, in addition to allowing predictions of likely hospital service needs such as re-admissions that are associated with long-term mortality.

DADennis Asante
Dennis Asante
Craig Steven McLachlanCraig Steven McLachlan
Craig Steven McLachlan
DPDavid Pickles
David Pickles
VIVivian Isaac
Vivian Isaac
Background: Rural populations experience poorer access to the necessary health services for chronic health conditions. Although studies of rural healthcare access continue to expand, most are based on quantitative data, yet normative views and lived experiences of rural adults might offer a better understanding of healthcare access and their specific unmet needs. This qualitative study sought the views of both rural-centric older people and healthcare professionals to understand health needs, barriers, and enablers of accessing health services, with a focus on chronic health condition(s). Methods: Between April and July 2022, separate in-depth interviews were conducted with 20 older people (≥60 years) in a rural South Australian community. Additionally, focus group interviews were conducted with 15 healthcare professionals involved in providing health services to older adults. Transcripts were coded using the NVivo software and data were thematically analysed. Results: Participants described a range of unmet care needs including chronic disease management, specialist care, psychological distress, and the need for formal care services. Four barriers to meeting care needs were identified: Workforce shortages, a lack of continuity of care, self-transportation, and long waiting times for appointments. Self-efficacy, social support, and positive provider attitudes emerged as crucial enabling factors of service use among rural ageing populations. Discussion: Older adults confront four broad ranges of unmet needs: Chronic disease management care, specialist care, psychological care, and formal care. There are potential facilitators, such as self-efficacy, provider positive attitudes, and social support, that could be leveraged to improve healthcare services access for older adults.

10 May 2018 in BMC Psychiatry
Verified
Journal Article
Open access
PDF file
VIVivian Isaac
Vivian Isaac
CWChia-Yi Jenny Wu
Chia-Yi Jenny Wu
Craig Steven McLachlanCraig Steven McLachlan
Craig Steven McLachlan
MLMing-Been Lee
Ming-Been Lee
Few studies have focused on exploring the association of self-efficacy and suicidal behaviour. In this study, we aim to investigate the association between health-related self-efficacy and suicidality outcomes, including lifetime/recent suicidal ideation, suicidal attempts and future intent of suicide. A computer-assisted telephone interview (CATI) system was used to draw potential respondents aged over 15 in Taiwan via telephone numbers, which were selected by a stratified proportional randomization method according to the distribution of population size in different geographic areas of Taiwan. We obtained available information on suicide behaviours for the analysis of 2110 participants. Logistic regression was applied to investigate the independent effect of health-related self-efficacy on life-time suicidal thoughts and attempts. Suicidality measured as suicide ideation and attempted suicide was reported as 12.6 and 2.7% respectively in the sample. Among those with suicide ideation, 9.8% had thoughts of future suicide intent. Female gender, low education, people living alone or separated, history of psychiatric disorders, substance abuse, poor self-rated mental health and physical health were associated with suicidality factors. Low health-related self-efficacy was associated with lifetime suicide ideation, prior suicide attempt and future suicidal intent. Among those with recent suicidal ideation, low health self-efficacy was independently associated with future suicide intent after adjustment of gender, age, education, marital status, substance abuse, psychological distress, poor mental and physical health. Health-related self-efficacy was associated with suicide risks across different time points from prior ideation to future intention. Evaluation of the progress of self-efficacy in health may be long-term targets of intervention in suicide prevention strategies.

1 February 2013 in The American Journal of Geriatric Psychiatry
Verified
Journal Article
Closed access
Lei FengLei Feng
Lei Feng
VIVivian Isaac
Vivian Isaac
SSSam Sim
Sam Sim
TNTze-Pin Ng
Tze-Pin Ng
KKK. Ranga R. Krishnan
K. Ranga R. Krishnan
MCMichael W. L. Chee
Michael W. L. Chee