Secondhand smoke in the densely populated urban setting: A cross-sectional survey of exposure, knowledge, attitudes, and respiratory symptoms.

Secondhand smoke (SHS) remains a common health threat in densely populated, urban settings. We estimated the prevalence of exposure and associated respiratory symptoms, knowledge, attitudes, and behaviors in a multi-ethnic, weighted sample of Singapore residents using a cross-sectional survey of 1806 adults. We weighted data to match the national population in terms of gender, ethnicity, and education level and analyzed data using descriptive statistics, bivariate analyses, multiple linear and logistic regressions, and a multinomial logistic regression model. About 88% of respondents reported regular SHS exposure. Nearly 57% reported exposure to neighbors' SHS at home. Respiratory symptoms were reported by 32.5% and significantly associated with exposure to daily (AOR = 2.63, 95% CI = 1.62-4.36), non-daily (AOR = 1.75, 95% CI = 1.14-2.77), and neighbors' (AOR = 1.37, 95% CI = 1.07-1.76) SHS. More knowledge of SHS was associated with male gender (ß = 0.28, p = 0.0009) and higher household income (linear trend; p = 0.0400). More negative attitudes to SHS were associated with older age (linear trend; p < 0.0001). Engaging in behaviors to avoid SHS was associated with a more negative attitude to SHS (AOR = 1.09-1.23). SHS exposure is common in Singapore's densely populated setting and associated with respiratory symptoms, even if exposure is non-daily or from neighboring homes.

Application of the network scale-up method to estimate the sizes of key populations for HIV in Singapore using online surveys.

INTRODUCTION: Singapore lacks robust data on the sizes of the key populations that are most at risk for HIV. Using the network scale-up method for hidden or hard-to-reach populations, we estimate the sizes of five key populations-male clients of female sex workers (MCFSW), men who have sex with men (MSM), female sex workers (FSW), people who inject drugs (PWID) and transgender people-and profile the ages and ethnicities of respondents with the high-risk contacts they report knowing. METHODS: We conducted a cross-sectional online survey between March and May 2019 (n = 2802) using a network scale-up instrument previously developed for Singapore. Participants were recruited using an existing panel and online advertising, and the sample reweighted by age, sex, ethnicity and education attained to represent the general adult population. We built a Bayesian hierarchical model to estimate the sizes of the five key populations for HIV in Singapore. RESULTS: After adjustment, the sizes of the at-risk populations are estimated to be: 76,800 (95% credible interval [CI]: 64,200-91,800) MCFSW; 139,000 (95% CI: 120,000-160,000) MSM; 8030 (95% CI: 3980-16,200) FSW; 3470 (95% CI: 1540-7830) PWID and 18,000 (95% CI: 14,000-23,200) transgender people. Generally, men reported knowing more people in all the high-risk groups; older people reported knowing more MCFSW, FSW and transgender people; and younger people reported knowing more MSM. There was a bimodal effect of age on those who reported knowing more PWIDs: people in their 20s and 60s reported more contacts. CONCLUSIONS: This study demonstrates that a size estimation study of hidden populations is quickly and efficiently scalable through using online surveys in a socially conservative society, like Singapore, where key populations are stigmatized or criminalized. The approach may be suitable in other countries where stigma is prevalent and where barriers to surveillance and data collection are numerous.

Assessing the Impact of Salt Reduction Initiatives on the Chronic Disease Burden of Singapore.

Globally, many countries are facing an increasing burden of chronic disease due to ageing populations, of which cardiovascular disease forms a large proportion. Excess dietary sodium contributes to cardiovascular disease risk and requires intervention at a population level. This study aimed to quantify the impact of several salt reduction initiatives on population health over a 30-year horizon using GeoDEMOS, a population model from Singapore. Four interventions were modelled in four demographic groups in 2020 for a total of 16 intervention scenarios. The effect of 0.5, 2.0, and 4.0 g/day reductions in daily salt consumption, along with adherence to the World Health Organization guidelines of a maximum of 5.0 g of salt each day, was modelled in the entire population, including the overweight and obese, the elderly, and diabetics. In each scenario, the number of averted incident cases of acute myocardial infarction and stroke, along with the disability-adjusted life years up to 2050, was monitored. We found 4.0 g/day reductions in salt consumption were the most effective when implemented across the entire population, resulting in 24,000 averted incident cases of cardiovascular disease and 215,000 disability-adjusted life years over 30 years. This is a large figure when compared with the 29,200 projected annual incident cases of cardiovascular disease in 2050. When targeted at specific high-risk demographic groups, the largest effects were observed in the overweight and obese, with the same intervention yielding 10,500 averted incident cases of cardiovascular disease and 91,500 disability-adjusted life years. Quantifying the benefits of salt reduction initiatives revealed a significant impact when administered across the entire population or the overweight and obese. Health promotion efforts directed toward sustainably reducing salt consumption will help to lower the chronic disease burden on the healthcare system in years to come.

Population anxiety and positive behaviour change during the COVID-19 epidemic: Cross-sectional surveys in Singapore, China and Italy.

BACKGROUND: On 31 December 2019, an epidemic of pneumonia of unknown aetiology was first reported in the city of Wuhan, Hubei Province, People's Republic of China. A rapidly progressing epidemic of COVID-19 ensued within China, with multiple exportations to other countries. We aimed to measure perceptions and responses towards COVID-19 in three countries to understand how population-level anxiety can be mitigated in the early phases of a pandemic. METHODS: Between February and March 2020, we conducted online surveys in Singapore, China and Italy with a total of 4505 respondents to measure respondents' knowledge, perceptions, anxiety and behaviours towards the COVID-19 epidemic, and identified factors associated with lower anxiety and more positive behavioural responses. RESULTS: Respondents reported high awareness of COVID-19 and its accompanying symptoms, comparable information-seeking habits and similarly high levels of information sufficiency, adherence to and acceptance of public health control measures. Higher self-efficacy was associated with lower anxiety levels in all three countries, while willingness to comply with restrictive measures and greater information sufficiency were associated with more positive behavioural changes to reduce spread of infection. CONCLUSION: Population-level anxiety and behavioural responses to an outbreak can be influenced by information provided. This should be used to inform future outbreak preparedness plans, taking into account the importance of increasing population-level self-efficacy and information sufficiency to reduce anxiety and promote positive behavioural changes.

Determining quarantine length and testing frequency for international border opening during the COVID-19 pandemic.

BACKGROUND: The COVID-19 pandemic has resulted in the closure or partial closure of international borders in almost all countries. Here, we investigate the efficacy of imported case detection considering quarantine length and different testing measures for travellers on arrival. METHODS: We examine eight broad border control strategies from utilizing quarantine alone, pre-testing, entry and exit testing, and testing during quarantine. In comparing the efficacy of these strategies, we calculate the probability of detecting travellers who have been infected up to 2 weeks pre-departure according to their estimated incubation and infectious period. We estimate the number of undetected infected travellers permitted entry for these strategies across a prevalence range of 0.1-2% per million travellers. RESULTS: At 14-day quarantine, on average 2.2% (range: 0.5-8.2%) of imported infections are missed across the strategies, leading to 22 (5-82) imported cases at 0.1% prevalence per million travellers, increasing up to 430 (106-1641) at 2%. The strategy utilizing exit testing results in 3.9% (3.1-4.9%) of imported cases being missed at 7-day quarantine, down to 0.4% (0.3-0.7%) at 21-day quarantine, and the introduction of daily testing, as the most risk averse strategy, reduces the proportion further to 2.5-4.2% at day 7 and 0.1-0.2% at day 21 dependent on the tests used. Rapid antigen testing every 3 days in quarantine leads to 3% being missed at 7 days and 0.7% at 14 days, which is comparable to PCR testing with a 24-hour turnaround. CONCLUSIONS: Mandatory testing, at a minimal of pre-testing and on arrival, is strongly recommended where the length of quarantining should then be determined by the destination country's level of risk averseness, pandemic preparedness and origin of travellers. Repeated testing during quarantining should also be utilized to mitigate case importation risk and reduce the quarantining duration required.

Scenarios to Manage the Demand for N95 Respirators for Healthcare Workers During the COVID-19 Pandemic.

BACKGROUND: By estimating N95 respirator demand based on simulated epidemics, we aim to assist planning efforts requiring estimations of respirator demand for the healthcare system to continue operating safely in the coming months. METHODS: We assess respiratory needs over the course of mild, moderate and severe epidemic scenarios within Singapore as a case study using a transmission dynamic model. The number of respirators required within the respiratory isolation wards and intensive care units was estimated over the course of the epidemic. We also considered single-use, extended-use and prolonged-use strategies for N95 respirators for use by healthcare workers treating suspected but negative (misclassified) or confirmed COVID-19 patients. RESULTS: Depending on the confirmed to misclassified case ratio, from 1:0 to 1:10, a range of 117.1 million to 1.1 billion masks are required for single-use. This decreases to 71.6-784.4 million for extended-use and 12.8-148.2 million for prolonged-use, representing a 31.8-38.9% and 86.5-89.1% reduction, respectively. CONCLUSION: An extended-use policy should be considered when short-term supply chains are strained but planning measures are in place to ensure long-term availability. With severe shortage expectations from a severe epidemic, as some European countries have experienced, prolonged use is necessary to prolong supply.