Chuen Seng Tan

Introduction: A key lever protecting people from secondhand smoke (SHS) exposure is not sharing the same space as smokers while they smoke. However, there is limited research on where exactly smokers choose to smoke, particularly in urban multi-ethnic Asian contexts. This study aims to identify distinct classes of smokers in Singapore and characterize smokers based on where they smoke. Methods: Using responses from 1,546 participants in Wave 2 of the Singapore Smokers’ Survey (2021), latent class analysis identified distinct smoker classes based on predefined smoking location options reported for home and outside home in the past month. Multinomial logistic regression was conducted to examine differences between classes on various covariates. Results: Three distinct latent classes of smokers were identified: “smoke at work” (75.7%), “smoke outside home” (14.0%), and “smoke everywhere” (10.2%). Ethnicity, housing type, marital status, hardcore smoking indicator (yes vs no), smoking status (daily vs occasional), time taken to smoke the first cigarette of the day after waking and perceiving family norms towards smoking habit were significant predictors of class membership. “Smoke at work” was the reference class. Those who “smoke everywhere” were more likely to be Malay, hardcore smokers and smoked their first cigarette of the day within 30 minutes of waking. Conclusions: Observed heterogeneity amongst Singapore smokers supports implementation of more targeted interventions for both smoking cessation and protecting nonsmokers from SHS exposure. Social norm change strategies may be considered, leveraging upon the roles of familial influence and ethnicity on where smokers choose to smoke. Implications: This study identifies three distinct smoker subgroups based on smoking locations—at work, outside the home, and everywhere—offering actionable insights for targeted interventions. Workplace-based cessation efforts can focus on those smoking at work, while promoting smoke-free homes may address familial pressures in the outside-home group. For those smoking everywhere, intensive interventions are needed to reduce SHS exposure across settings. Multinomial regression reveals that familial disapproval, ethnicity, and housing type significantly influence smoking patterns, highlighting the importance of culturally tailored interventions that leverage social, familial, and environmental factors to reduce smoking prevalence and SHS exposure.

Background: Increasing physical inactivity is a primary risk factor for diabetes and hypertension, contributing to rising health care expenditure and productivity losses. As Singapore’s aging population grows, there is an increased disease burden on Singapore’s health systems. Large-scale physical activity interventions could potentially reduce the disease burden but face challenges with the uncertainty of long-term health impact and high implementation costs, hindering their adoption. Objective: We examined the cost-effectiveness of the Singapore National Steps Challenge (NSC), an annual nationwide mobile health (mHealth) intervention to increase physical activity, from both the health care provider perspective, which only considers the direct costs, and the societal perspective, which considers both the direct and indirect costs. Methods: We used a Markov model to assess the long-term impact of increased physical activity from the NSC on adults aged 17 years and older. A Monte Carlo simulation with 1000 samples was conducted to compare two situations: the NSC conducted yearly for 10 years against a no-intervention situation with no NSC. The model projected inpatient and outpatient costs and mortality arising from diabetes and hypertension, as well as their complications. Health outcomes were expressed in terms of the quality-adjusted life-years (QALYs) gained. All future costs and QALYs were discounted at 3% per annum. Sensitivity analyses were done to test the robustness of our model results. Results: We estimated that conducting the NSC yearly for 10 years with a mean cohort size of 654,500 participants was projected to prevent 6200 diabetes cases (95% credible interval 3700 to 9100), 10,500 hypertension cases (95% credible interval 6550 to 15,200), and 4930 deaths (95% credible interval 3260 to 6930). This led to a reduction in health care costs of SGD (Singapore dollar) 448 million (95% credible interval SGD 132 million to SGD 1.09 billion; SGD 1=US $0.73 for the year 2019). There would be 78,800 (95% credible interval 55,700 to 102,000) QALYs gained. Using a willingness-to-pay threshold of SGD 10,000 per QALY gained, the NSC would be cost-saving. When indirect costs were included, the NSC was estimated to reduce societal costs by SGD 1.41 billion (95% credible interval SGD 353 million to SGD 3.80 billion). The model was most sensitive to changes in the inpatient cost of treatment for diabetes complications, time horizon, and program compliance. Conclusions: In this modeling study, increasing physical activity by conducting a yearly nationwide physical activity intervention was cost-saving, preventing diabetes and hypertension and reducing mortality from these diseases. Our results provide important information for decision-making in countries that may consider introducing similar large-scale physical activity programs.

Purpose Cardiogenic shock is associated with high mortality. In refractory shock, it is unclear if mechanical circulatory support (MCS) devices improve survival. We conducted a network meta-analysis to determine which MCS devices confers greatest benefit. Methods We searched MEDLINE, Embase, and Scopus databases through 27 August 2023 for relevant randomized controlled trials (RCTs) and propensity score-matched studies (PSMs). We conducted frequentist network meta-analysis, investigating mortality (either 30 days or in-hospital) as the primary outcome. We assessed risk of bias (Cochrane risk of bias 2.0 tool/Newcastle–Ottawa Scale) and as sensitivity analysis reconstructed survival data from published survival curves for a one-stage unadjusted individual patient data (IPD) meta-analysis using a stratified Cox model. Results We included 38 studies (48,749 patients), mostly reporting on patients with Society for Cardiovascular Angiography and Intervention shock stages C–E cardiogenic shock. Compared with no MCS, extracorporeal membrane oxygenation with intra-aortic balloon pump (ECMO-IABP; network odds ratio [OR]: 0.54, 95% confidence interval (CI): 0.33–0.86, moderate certainty) was associated with lower mortality. There were no differences in mortality between ECMO, IABP, microaxial ventricular assist device (mVAD), ECMO-mVAD, centrifugal VAD, or mVAD-IABP and no MCS (all very low certainty). Our one-stage IPD survival meta-analysis based on the stratified Cox model found only ECMO-IABP was associated with lower mortality (hazard ratio, HR, 0.55, 95% CI 0.46–0.66). Conclusion In patients with cardiogenic shock, ECMO-IABP may reduce mortality, while other MCS devices did not reduce mortality. However, this must be interpreted within the context of inter-study heterogeneity and limited certainty of evidence.

Introduction: Relationships between secondhand smoke exposure (SHSE) in various temporal and physical settings are not fully studied despite its adverse impacts on human health, especially in multi-ethnic Asian populations. We investigated associations of childhood and current SHSE at home...

Background: Ecological momentary assessments (EMAs) are short, repeated surveys designed to collect information on experiences in real-time, real-life contexts. Embedding periodic bursts of EMAs within cohort studies enables the study of experiences on multiple timescales and could greatly enhance the accuracy of self-reported information. However, the burden on participants may be high and should be minimized to optimize EMA response rates. Objective: We aimed to evaluate the effects of study design features on EMA response rates. Methods: Embedded within an ongoing cohort study (Health@NUS), 3 bursts of EMAs were implemented over a 7-month period (April to October 2021). The response rate (percentage of completed EMA surveys from all sent EMA surveys; 30-42 individual EMA surveys sent/burst) for each burst was examined. Following a low response rate in burst 1, changes were made to the subsequent implementation strategy (SMS text message announcements instead of emails). In addition, 2 consecutive randomized controlled trials were conducted to evaluate the efficacy of 4 different reward structures (with fixed and bonus components) and 2 different schedule lengths (7 or 14 d) on changes to the EMA response rate. Analyses were conducted from 2021 to 2022 using ANOVA and analysis of covariance to examine group differences and mixed models to assess changes across all 3 bursts. Results: Participants (N=384) were university students (n=232, 60.4% female; mean age 23, SD 1.3 y) in Singapore. Changing the reward structure did not significantly change the response rate (F3,380=1.75; P=.16). Changing the schedule length did significantly change the response rate (F1,382=6.23; P=.01); the response rate was higher for the longer schedule (14 d; mean 48.34%, SD 33.17%) than the shorter schedule (7 d; mean 38.52%, SD 33.44%). The average response rate was higher in burst 2 and burst 3 (mean 50.56, SD 33.61 and mean 48.34, SD 33.17, respectively) than in burst 1 (mean 25.78, SD 30.12), and the difference was statistically significant (F2,766=93.83; P<.001). Conclusions: Small changes to the implementation strategy (SMS text messages instead of emails) may have contributed to increasing the response rate over time. Changing the available rewards did not lead to a significant difference in the response rate, whereas changing the schedule length did lead to a significant difference in the response rate. Our study provides novel insights on how to implement EMA surveys in ongoing cohort studies. This knowledge is essential for conducting high-quality studies using EMA surveys. Trial Registration: ClinicalTrials.gov NCT05154227; https://clinicaltrials.gov/ct2/show/NCT05154227

Aims: To examine the association between domain-specific physical activity (PA) and cardiometabolic factors with longitudinal data, which is limited in current literature. Methods: Participants who attended the Singapore Multi-Ethnic Cohort and follow-up surveys were included in this study (N = 3950, mean age: 44.7 y, female: 57.9%). Self-reported moderate- to vigorous-intensity PA (MVPA) for each domain (leisure-time, transportation, occupation, and household) was categorized into 4 levels: no, low, middle, and high MVPA. The longitudinal associations of domain-specific MVPA with cardiometabolic factors including systolic and diastolic blood pressures, low-density and high-density lipoprotein cholesterols, triglycerides, and body mass index were examined using Generalized Estimating Equations, accounting for confounding factors and repeated measurements. Results: There were 5.2% participants who had no MVPA. For each domain, this rate ranged from 22.6% (household) to 83.3% (occupation). Leisure-time and occupation MVPAs had positive and linear associations with high-density lipoprotein cholesterols, corresponding to 0.030 (95% confidence interval, 0.015 to 0.045) mmol/L (leisure-time) and 0.063 (95% confidence interval, 0.043 to 0.083) mmol/L (occupation), when compared high with no respective MVPA. Occupation and household MVPAs were associated with low-density lipoprotein cholesterol. Transportation and occupation exhibited a positive and linear relationship with diastolic blood pressure. None of the domains were associated with body mass index, systolic blood pressures, or triglycerides. Conclusions: This study showed that each domain had differential association with individual cardiometabolic risk factors. As occupation, transportation, or household PA had unfavorable associations with low-density lipoprotein cholesterol or diastolic blood pressure, the overall beneficial impact of higher PA levels may not necessarily hold in the context of domain-specific PA and cardiovascular health. Further investigation is needed to corroborate our findings.

Objective Stroke, a common illness in older adults, accounts for up to 4% of direct medical costs in developed nations. Informal caregiving contributing a significant proportion of economic burden post-stroke warrants a deeper understanding of the caregiving context to sustain caregiving arrangement. While literature exists describing differences in motivation and preferences of caregivers, limited literature explores differences in caregiving experiences of different types of caregivers (ie, spouse, adult-child, sibling or others). Addressing this gap, our study aimed to explore the caregiving experience of stroke survivors and their family caregivers across different caregiver identities in an Asian setting. Design Qualitative descriptive study. Setting Community setting. Participants We conducted semi-structured interviews with 26 stroke survivors and 35 caregivers purposively sampled from an outpatient rehabilitation setting, an outpatient clinic and a support organisation. Data were analysed using thematic analysis. Outcome measures Themes including caregiving experience of stroke survivors and their family caregivers across different caregiver identities. Results Following five themes were reported: caregiver reserve, coping strategies, caregiver burden, competing commitments and role of foreign domestic worker (FDW) in family caregiving. Spouse caregivers were less willing to ask for help, commonly adopted faith-based, and spacing or recharging types of coping, reported emotional strain and shared limited accounts of FDWs. Adult-child caregivers were more willing to ask for help, engaged in alternative care arrangements involving FDWs, commonly adopted action-focussed coping and reported multidimensional caregiver burden. Conclusion Our findings illustrated the heterogeneity in factors affecting caregiving experience across spouse and adult-child caregivers. Practical implications include conducting a needs assessment for caregiver-stroke survivor dyads and providing tailored support, training and information to help caregivers cope better.

BACKGROUND Increasing physical inactivity is a primary risk factor for diabetes and hypertension, contributing to rising healthcare expenditure and productivity losses. As Singapore's ageing population grows, there is an increased disease burden on her health systems. Large-scale physical activity interventions could potentially reduce the disease burden but face challenges in the uncertainty of long-term health impact and high implementation costs, hindering their adoption. OBJECTIVE We examined the cost-effectiveness of the Singapore National Steps Challenge (NSC), an annual nationwide mHealth intervention to increase physical activity, from both the healthcare provider’s perspective which only considers the direct costs and the societal perspective which considers both the direct and indirect costs. METHODS We used a Markov model to assess the long-term impact of increased physical activity from NSC on adults aged 17 and above. A Monte Carlo simulation with 1,000 samples was conducted to compare two situations: NSC conducted yearly for 10 years against a no-intervention situation with no NSC. The model projected inpatient and outpatient costs and mortality arising from diabetes and hypertension, and their complications. Health outcomes were expressed in terms of the quality-adjusted life-years (QALYs) gained. All future costs and QALYs were discounted at 3% per annum. Sensitivity analyses were done to test the robustness of our model results. RESULTS We estimated that conducting NSC yearly for 10 years on a mean cohort size of 654,500 participants is projected to prevent 6,200 diabetes cases (95% credible interval 3,700 to 9,100), 10,500 hypertension cases (6,550 to 15,200) and 4,930 deaths (3,260 to 6,930). This led to a reduction in healthcare costs of SGD448 million (132 million to 1.09 billion). There would be 78,800 QALYs (55,700 to 102,000) gained. Using a willingness-to-pay threshold of SGD10,000 per QALY gained, NSC would be cost-saving. When indirect costs were included, NSC was estimated to reduce societal costs by SGD1.41 billion (353 million to 3.80 billion). The model was most sensitive to changes in the inpatient cost of treatment for diabetes complications, time horizon and programme compliance. CONCLUSIONS In this modelling study, increasing physical activity by conducting a yearly nationwide physical activity intervention was cost-saving, preventing diabetes and hypertension and reducing mortality from these diseases. Our results provide important information for decision-making in countries that may consider introducing similar large-scale physical activity programmes. CLINICALTRIAL

Journal of Medical Internet Research - International Scientific Journal for Medical Research, Information and Communication on the Internet #Preprint #PeerReviewMe: Warning: This is a unreviewed preprint. Readers are warned that the document has not been peer-reviewed by expert/patient reviewers or an academic editor, may contain misleading claims, and is likely to undergo changes before final publication, if accepted, or may have been rejected/withdrawn. Readers with interest and expertise are encouraged to sign up as peer-reviewer, if the paper is within an open peer-review period. Please cite this preprint only for review purposes or for grant applications and CVs (if you are the author). Background: Ecological momentary assessments (EMAs) are short, repeated surveys designed to collect information on experiences in real-time, real-life contexts. Embedding periodic bursts of EMAs within cohort studies enables the study of experiences on multiple timescales and could greatly enhance the accuracy of self-reported information. However, the burden on participants may be high and should be minimized to optimize EMA response rates. Objective: We aimed to evaluate the effects of study design features on EMA response rates. Methods: Embedded within an ongoing cohort study (Health@NUS), 3 bursts of EMAs were implemented over a 7-month period (April to October 2021). The response rate (percentage of completed EMA surveys from all sent EMA surveys; 30-42 individual EMA surveys sent/burst) for each burst was examined. Following a low response rate in burst 1, changes were made to the subsequent implementation strategy (SMS text message announcements instead of emails). In addition, 2 consecutive randomized controlled trials were conducted to evaluate the efficacy of 4 different reward structures (with fixed and bonus components) and 2 different schedule lengths (7 or 14 d) on changes to the EMA response rate. Analyses were conducted from 2021 to 2022 using ANOVA and analysis of covariance to examine group differences and mixed models to assess changes across all 3 bursts. Results: Participants (N=384) were university students (n=232, 60.4% female; mean age 23, SD 1.3 y) in Singapore. Changing the reward structure did not significantly change the response rate (F_3,380=1.75; P=.16). Changing the schedule length did significantly change the response rate (F_1,382=6.23; P=.01); the response rate was higher for the longer schedule (14 d; mean 48.34%, SD 33.17%) than the shorter schedule (7 d; mean 38.52%, SD 33.44%). The average response rate was higher in burst 2 and burst 3 (mean 50.56, SD 33.61 and mean 48.34, SD 33.17, respectively) than in burst 1 (mean 25.78, SD 30.12), and the difference was statistically significant (F_2,766=93.83; P<.001). Conclusions: Small changes to the implementation strategy (SMS text messages instead of emails) may have contributed to increasing the response rate over time. Changing the available rewards did not lead to a significant difference in the response rate, whereas changing the schedule length did lead to a significant difference in the response rate. Our study provides novel insights on how to implement EMA surveys in ongoing cohort studies. This knowledge is essential for conducting high-quality studies using EMA surveys. Trial Registration: ClinicalTrials.gov NCT05154227; https://clinicaltrials.gov/ct2/show/NCT05154227

Background: There is a compelling need for an innovative and creative approach to promote social connectedness among older adults to optimize their well-being and quality of life. One possible solution may be through a digital intergenerational program. Objective: This realist review aimed to identify existing digital intergenerational programs that were used to reduce loneliness or social isolation among older adults and analyze them in terms of strategy, context, mechanisms, and outcomes. Methods: We performed a realist review with an extensive search of published and gray literature. For scholarly literature, we searched PubMed, Embase, CINAHL, PsycINFO (Ovid), and Social Sciences Citation Index databases for articles published between January 2000 to August 2020. A grey literature search was performed using the Google search engine, and the search was completed in May 2021. We included programs that evaluated digital intergenerational programs for older adults, which described outcomes of loneliness or social isolation. We included quantitative, mixed methods, and qualitative studies, as well as relevant theoretical papers, policy documents, and implementation documents. The studies were appraised based on their relevance and rigor. We synthesized the available evidence from the literature into Strategy-Context-Mechanism-Outcome (S-C-M-O) configurations to better understand what, when, and how programs work. Results: A total of 31 documents reporting 27 digital intergenerational programs were reviewed. Our final results identified 4 S-C-M-O configurations. For S-C-M-O configuration 1, we found that for community-dwelling older adults, provision of access to and training in digital technology may increase older adults’ self-efficacy in digital devices and therefore increase the use of digital communication with family. In S-C-M-O configuration 2, digital psychosocial support and educational interventions from nurses were found to be useful in reducing loneliness among community-dwelling older adults. In S-C-M-O configuration 3, a video call with a student or family was found to reduce loneliness among older adults residing in long-term residential care facilities. Finally, for S-C-M-O configuration 4, we found that behavioral activation provided through videoconferencing by a lay coach may be useful in reducing loneliness among older adults who are lonely. However, as almost half (11/27, 41%) of the included programs only reported quantitative results, this review focused on screening the discussion section of publications to identify author opinions or any qualitative information to elucidate the mechanisms of how programs work. Conclusions: This review identified the key strategy, context, and mechanism influencing the success of programs that promote intergenerational interaction through digital means. This review revealed that different strategies should be adopted for different groups of older adults (eg, older adults who are lonely, older adults who reside in long-term residential care facilities, and community-dwelling older adults). The S-C-M-O configurations should be considered when designing and implementing digital intergenerational programs for older adults.