The impact of COVID-19 vaccination prior to SARS-CoV-2 infection on prevalence of long COVID among a population-based probability sample of Michiganders, 2020-2022

PURPOSE

To estimate the association between COVID-19 vaccination status at the time of COVID-19 onset and long COVID prevalence.

METHODS

We used data from the Michigan COVID-19 Recovery Surveillance Study, a population-based probability sample of adults with COVID-19 (n = 4695). We considered 30-day and 90-day long COVID (illness duration ≥30 or ≥90 days, respectively), using Poisson regression to estimate prevalence ratios (PRs) comparing vaccinated (completed an initial series ≥14 days before COVID-19 onset) to unvaccinated individuals (received 0 doses before COVID-19 onset), accounting for differences in age, sex, race and ethnicity, education, employment, health insurance, and rurality/urbanicity. The full unvaccinated comparison group was further divided into historic and concurrent comparison groups based on timing of COVID-19 onset relative to vaccine availability. We used inverse probability of treatment weights to account for sociodemographic differences between groups.

RESULTS

Compared to the full unvaccinated comparison group, the adjusted prevalence of 30-day and 90-day long COVID were lower among vaccinated individuals [PR30-day= 0.57(95%CI:0.49,0.66); PR90-day= 0.42(95%CI:0.34,0.53)]. Estimates were consistent across comparison groups (full, historic, and concurrent).

CONCLUSIONS

Long COVID prevalence was 40-60% lower among adults vaccinated (vs. unvaccinated) prior to their COVID-19 onset. COVID-19 vaccination may be an important tool to reduce the burden of long COVID.

Transition Path Sampling Study of Engineered Enzymes That Catalyze the Morita-Baylis-Hillman Reaction: Why Is Enzyme Design so Difficult?

It is hoped that artificial enzymes designed in laboratories can be efficient alternatives to chemical catalysts that have been used to synthesize organic molecules. However, the design of artificial enzymes is challenging and requires a detailed molecular-level analysis to understand the mechanism they promote in order to design efficient variants. In this study, we computationally investigate the mechanism of proficient Morita-Baylis-Hillman enzymes developed using a combination of computational design and directed evolution. The powerful transition path sampling method coupled with in-depth post-processing analysis has been successfully used to elucidate the different chemical pathways, transition states, protein dynamics, and free energy barriers of reactions catalyzed by such laboratory-optimized enzymes. This research provides an explanation for how different chemical modifications in an enzyme affect its catalytic activity in ways that are not predictable by static design algorithms.

The Burden of Narcolepsy in Adults: A Population Sampling Study Using Personal Media

OBJECTIVE

To obtain insight in the spectrum of narcolepsy symptoms and associated burden in a large cohort of patients.

METHODS

We used the Narcolepsy Monitor, a mobile app, to easily rate the presence and burden of 20 narcolepsy symptoms. Baseline measures were obtained and analyzed from 746 users aged between 18 and 75 years with a reported diagnosis of narcolepsy.

RESULTS

Median age was 33.0 years (IQR 25.0-43.0), median Ullanlinna Narcolepsy Scale 19 (IQR 14.0-26.0), 78% reported using narcolepsy pharmacotherapy. Excessive daytime sleepiness (97.2%) and lack of energy were most often present (95.0%) and most often caused a high burden (79.7% and 76.1% respectively). Cognitive symptoms (concentration 93.0%, memory 91.4%) and psychiatric symptoms (mood 76.8%, anxiety/panic 76.4%) were relatively often reported to be present and burdensome. Conversely, sleep paralysis and cataplexy were least often reported as highly bothersome. Females experienced a higher burden for anxiety/panic, memory, and lack of energy.

CONCLUSIONS

This study supports the notion of an elaborate narcolepsy symptom spectrum. Each symptom's contribution to the experienced burden varied, but lesser-known symptoms did significantly add to this as well. This emphasizes the need to not only focus treatment on the classical core symptoms of narcolepsy.

The Association between State-Level Structural Racism and Alcohol and Tobacco Use Behaviors among a National Probability Sample of Black Americans

BACKGROUND

Structural racism is how society maintains and promotes racial hierarchy and discrimination through established and interconnected systems. Structural racism is theorized to promote alcohol and tobacco use, which are risk factors for adverse health and cancer-health outcomes. The current study assesses the association between measures of state-level structural racism and alcohol and tobacco use among a national sample of 1,946 Black Americans.

METHODS

An existing composite index of state-level structural racism including five dimensions (subscales; i.e., residential segregation and employment, economic, incarceration, and educational inequities) was merged with individual-level data from a national sample dataset. Hierarchical linear and logistic regression models, accounting for participant clustering at the state level, assessed associations between structural racism and frequency of alcohol use, frequency of binge drinking, smoking status, and smoking frequency. Two models were estimated for each behavioral outcome, one using the composite structural racism index and one modeling dimensions of structural racism in lieu of the composite measure, each controlling for individual-level covariates.

RESULTS

Results indicated positive associations between the incarceration dimension of the structural racism index and binge drinking frequency, smoking status, and smoking frequency. An inverse association was detected between the education dimension and smoking status.

CONCLUSIONS

Results suggest that state-level structural racism expressed in incarceration disparities, is positively associated with alcohol and tobacco use among Black Americans.

IMPACT

Addressing structural racism, particularly in incarceration practices, through multilevel policy and intervention may help to reduce population-wide alcohol and tobacco use behaviors and improve the health outcomes of Black populations.

Efficient designs and analysis of two-phase studies with longitudinal binary data

Researchers interested in understanding the relationship between a readily available longitudinal binary outcome and a novel biomarker exposure can be confronted with ascertainment costs that limit sample size. In such settings, two-phase studies can be cost-effective solutions that allow researchers to target informative individuals for exposure ascertainment and increase estimation precision for time-varying and/or time-fixed exposure coefficients. In this paper, we introduce a novel class of residual-dependent sampling (RDS) designs that select informative individuals using data available on the longitudinal outcome and inexpensive covariates. Together with the RDS designs, we propose a semiparametric analysis approach that efficiently uses all data to estimate the parameters. We describe a numerically stable and computationally efficient EM algorithm to maximize the semiparametric likelihood. We examine the finite sample operating characteristics of the proposed approaches through extensive simulation studies, and compare the efficiency of our designs and analysis approach with existing ones. We illustrate the usefulness of the proposed RDS designs and analysis method in practice by studying the association between a genetic marker and poor lung function among patients enrolled in the Lung Health Study (Connett et al, 1993).

Is the stability of folates in dried blood microsamples sufficient to perform home-sampling studies?

Dried blood microsampling is increasingly used for home-sampling and epidemiological studies because of its multiple advantages, including an often greatly improved analyte stability. However, a critical assessment of the stability under realistic conditions should always be performed as part of the validation, especially for unstable molecules like folates (vitamin B9). Here, the objective was to determine whether folate stability in dried blood microsamples is sufficient to allow the set-up of home-sampling studies for the monitoring of folate status in e.g., women of reproductive age. An extensive set of stability experiments was performed to evaluate the stability of the main folate vitamer 5-methyltetrahydrofolate (5MTHF), its oxidation product MeFOX and the minor non-methyl folate vitamers 10-formylfolic acid (10FoFA), 5,10-methenyltetrahydrofolate (5,10CH+THF) and tetrahydrofolate (THF) in dried blood microsamples using volumetric absorptive microsampling (VAMS) or regular dried blood spots (DBS). The evaluations included (EDTA-anticoagulated blood was collected from a single donor measured in four replicates per condition and time point): (i) the effect of temperature (-20 °C, 4 °C, ambient temperature and 37 °C), (ii) the effect of light (during drying and storage) and humidity, and (iii) the effect of storage under vacuum and pretreatment of the microsamples with stabilizing agents on folate stability. At -20 °C and 4 °C, all folate levels were within 85 to 115% of the baseline value up till two weeks of storage in both VAMS samples and DBS. However, at room temperature the stability of the analyzed folates was only consistently observed up till three days in VAMS samples, and for none of the folates at 37 °C. Humidity had a major impact on 5,10CH+THF stability, but this could be easily improved by using desiccant. Both vacuum treatment and pretreatment of microsamples with 0.1% DL-dithiothreitol and 5% butylated hydroxytoluene improved the stability at room temperature in VAMS samples, but these effects were limited at 37 °C and in DBS. Overall, the stability of the individual folate vitamers proved to be challenging and strongly temperature- and time-dependent. Nonetheless, if controlled transport (temperature and duration) can be assured, the set-up of home-sampling studies to evaluate the folate status using dried blood microsamples can still be beneficial.

Prevalence of mental disorders among middle-aged population of primary healthcare centers in Northeastern Iran

BACKGROUND

Primary healthcare centers (PHCs) serve as the cornerstone of accessible medical services in society, playing a crucial role in screening, detecting, and treating various health issues. This study aimed to investigate the prevalence of psychiatric disorders in middle-aged individuals who refer to PHCs and the potential of PHCs in diagnosing mental disorders.

METHODS

This cross-sectional study was implemented at PHCs under the supervision of Mashhad University of Medical Sciences (MUMS) in northeast Iran in 2018. The enrolled subjects were middle-aged adults who had electronic medical records in SINA, an integrated health management system, and the electronic medical records of MUMS. The prevalence of psychiatric disorders by type and their relationship with demographic information was evaluated by a Chi-square test using SPSS 22.

RESULTS

This study involved 218,341 middle-aged participants. Prevalence of psychiatric disorders was 8.59%, and depression (53.72%) and anxiety (42.02%) were the most common psychiatric disorders in both males and females. The prevalence of mental disorders was significantly higher in females than in males (88.18% vs. 18.81%; P < 0.0001). Indeed, a significant higher prevalence of depression, anxiety, somatoform, childhood psychiatric disorder, and bipolar disorders was observed in females compared to males (P < 0.05). In addition, individuals between the age of 45-60 years, and those from rural areas showed more prevalence of mental disorders than others, but these differences were not significant.

CONCLUSIONS

Considering the previous studies in Iran, the prevalence of mental disorders among patients presenting to PHCs was noticeably lower than expected rates. It seems probable that this huge difference is due to poor screening and detection of mental illness in PHCs of MUMS. It is recommended that health policymakers pursue specific measures to make PHCs more helpful for people with mental health problems in the community.

Highly robust quantum mechanics and umbrella sampling studies on inclusion complexes of curcumin and β-cyclodextrin

The poor aqueous solubility of curcumin (CUR) obstructs its wide utilization in nutraceuticals, cosmetics, and pharmaceutical companies. This study is dedicated to investigate the stability of CUR inside the hydrophobic pocket of β-cyclodextrin (β-CD), hydroxypropyl-β-CD (HP-β-CD), and 2,6-Di-O-methyl-β-CD (DM-β-CD). Initially, molecular mechanics (MM) calculations and subsequently quantum mechanical (QM) calculations were performed on inclusion complexes to strengthen the MM results. We performed microsecond timescale MD simulations to observe the structural dynamics of CUR inside the cavity of CDs. We elucidated the most stable binding orientations of CUR inside the cavity of CDs based on binding free energy obtained from the Molecular Mechanics Poisson-Boltzmann Surface Area (MM-PBSA) and umbrella sampling simulations. Furthermore, the two-layered ONIOM (B3LYP/6-311+G(2d,p):PM7) method with CPCM implicit water model was used to derive the complete energetics and thermodynamics of inclusion complexes at 1:1 stoichiometry. Each inclusion reaction was exothermic and spontaneous. The chemical reactivity and kinetic stability of inclusion complexes were described by HOMO-LUMO molecular orbital energies. In conclusion, our studies revealed that HP-β-CD had the highest binding affinity for CUR with the most negative complexation energy (-6520.69 kJ/mol) and Gibb's free energy change (-6448.20 kJ/mol). The atomic-level investigation of noncovalent interactions between CUR and the hydroxypropyl groups in HP-β-CD/CUR complex may be helpful to drive new derivatives of HP-β-CD with better host capacity. The computational strategy adopted here might serve as a benchmark for increasing the solubility of numerous clinically significant molecules.

Asexual or not sure: Findings from a probability sample of undergraduate students

OBJECTIVE

Present study aims to: 1) examine demographic correlates of LGB, asexual, or not sure participants 2) describe the prevalence of diverse sexual behaviors, 3) assess the prevalence of event-level sexual behaviors and 4) examine predictors of sexual pleasure.

PARTICIPANTS

761 non-heterosexual undergraduates at a large, public U.S. university.

METHODS

Randomly sampled undergraduate students completed a confidential, cross-sectional online survey.

RESULTS

Of 761 non-heterosexual respondents; 567 identified as LGB, 47 asexual, and 147 not sure. Asexual students, those not sure were less likely to report having engaged in solo and partnered sexual activities and report sexual activities being less pleasurable at most recent sexual event, compared with LGB students. This difference (relative to LGB) became nonsignificant when accounting for reported sexual activities.

CONCLUSIONS

Our findings inform how college students define and experience their sexual identities and assist college health professionals in training on sexuality and prevention of risk factors.

Prevalence and nature of workplace bullying and harassment and associations with mental health conditions in England: a cross-sectional probability sample survey

BACKGROUND

Evidence on workplace bullying and harassment (WBH) in the UK has not used probability-sample surveys with robust mental health assessments. This study aimed to profile the prevalence and nature of WBH in England, identify inequalities in WBH exposure, and quantify adjusted associations with mental health.

METHODS

Data were from the 2014 Adult Psychiatric Morbidity Survey, a cross-sectional probability-sample survey of the household population in England, interviewed with verbal informed consent. Criteria for inclusion in the secondary analysis were being aged 16-70 years and in paid work in the past month (n=3838). Common mental disorders were assessed using the Clinical Interview Schedule-Revised and mental wellbeing using the Warwick-Edinburgh Mental Wellbeing Scale. Analyses were weighted. We examined associations between past-year WBH and current common mental disorders using multivariable regression modelling, adjusting for demographic and socioeconomic factors. Interaction terms tested for gender differences in associations. The study received ethics approval (ETH21220-299).

FINDINGS

One in ten employees (10·6% (weighted), n=444/3838) reported past-year experience of WBH, with rates higher in women (12·2%, n=284/2189); those of mixed, multiple, and other ethnicity (21·0%, n=15/92); and people in debt (15·2%, n=50/281) or living in cold homes (14·6%, n=42/234). Most commonly identified perpetrators of WBH were line managers (53·6%, n=244/444) or colleagues (42·8%, n=194/444). Excessive criticism (49·3%, n=212/444), verbal abuse (42·6%, n=187/444), and humiliation (31·4%, n=142/444) were the most common types. WBH was associated with all adverse mental health indicators, including common mental disorders (adjusted odds ratio [aOR] 2·65, 95% CI 2·02-3·49), and 11 of 14 mental wellbeing indicators, including lower levels of confidence (aOR 0·57, 0·46-0·72) and of closeness to others (aOR 0·57, 0·46-0·72). Patterns of association between WBH and mental health were similar in men and women.

INTERPRETATION

These findings reinforce a need for more cohesive UK legislation at the national level; guidance on recognition of bullying behaviours for employees, managers, and human resources at the organisational level, focusing on prevention and early intervention, and increased awareness of the impact of WBH on mental health among health-service practitioners. Study limitations include reliance on cross-sectional data collected before pandemic-related and other major changes in workplace practices. Longitudinal data are needed to improve evidence on causality and the longevity of mental health impacts.

FUNDING

UK Prevention Research Partnership.

Innovative Strategies for Remotely Sampling Hard-to-Reach Populations: Assessing Phone Versus Internet Respondent-Driven Sampling Approaches Among Venezuelan Refugees and Migrants in Colombia

It is challenging to quantitatively measure the health vulnerability and risk factors of refugees and migrants residing outside of formal settlement settings. For hard-to-reach populations without available sampling frames, researchers have increasingly turned to novel sampling and statistical methods, like respondent-driven sampling (RDS). "Standard" RDS is typically conducted face-to-face at fixed sites. However, during the coronavirus disease 2019 (COVID-19) pandemic, face-to-face survey methods and recruitment approaches posed high potential risk of virus transmission and infection, making remote RDS approaches optimal. In this paper, we explore the feasibility of implementing telephone and Internet RDS strategies to assess challenges faced by Venezuelan refugees and migrants in the city of Bogotá, Colombia's capital, and the department of Norte de Santander, the main Venezuelan-Colombian border crossing site. We describe RDS assumptions, survey design, formative research, and the implementation of both strategies and present diagnostics for determining whether assumptions are met. Phone-based recruitment strategies in both locations and the Internet strategy in Bogotá achieved their calculated sample size; however, the Internet strategy in Norte de Santander did not. Most RDS assumptions were sufficiently met at sites where sample sizes were reached. These surveys provide valuable lessons for implementing innovative remote strategies with which to study hard-to-reach populations such as refugees and migrants.

Implementation of web-based respondent driven sampling in epidemiological studies

BACKGROUND

Respondent-driven sampling (RDS) is a peer chain-recruitment method for populations without a sampling frame or that are hard-to-reach. Although RDS is usually done face-to-face, the online version (WebRDS) has drawn a lot of attention as it has many potential benefits, despite this, to date there is no clear framework for its implementation. This article aims to provide guidance for researchers who want to recruit through a WebRDS.

METHODS

Description of the development phase: guidance is provided addressing aspects related to the formative research, the design of the questionnaire, the implementation of the coupon system using a free software and the diffusion plan, using as an example a web-based cross-sectional study conducted in Spain between April and June 2022 describing the working conditions and health status of homecare workers for dependent people.

RESULTS

The application of the survey: we discuss about the monitoring strategies throughout the recruitment process and potential problems along with proposed solutions.

CONCLUSIONS

Under certain conditions, it is possible to obtain a sample with recruitment performance similar to that of other RDS without the need for monetary incentives and using a free access software, considerably reducing costs and allowing its use to be extended to other research groups.

No association between numerical ability and politically motivated reasoning in a large US probability sample

The highly influential theory of "Motivated System 2 Reasoning" argues that analytical, deliberative ("System 2") reasoning is hijacked by identity when considering ideologically charged issues-leading people who are more likely to engage in such reasoning to be more polarized, rather than more accurate. Here, we fail to replicate the key empirical support for this theory across five contentious issues, using a large gold-standard nationally representative probability sample of Americans. While participants were more accurate in evaluating a contingency table when the outcome aligned with their politics (even when controlling for prior beliefs), we find that participants with higher numeracy were more accurate in evaluating the contingency table, regardless of whether or not the table's outcome aligned with their politics. These findings call for a reconsideration of the effect of identity on analytical reasoning.

Occurrence and carcinogenic potential of airborne PBDD/Fs and PCDD/Fs around a large-scale municipal solid waste incinerator: A long-term passive air sampling study

Municipal solid waste incinerator (MSWI) not only is deemed one of the uppermost sources of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), but also produces substantial amount of polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) owing to the existence of brominated flame retardants (BFRs) in the waste. So far, however, PBDD/Fs in the vicinal environments of MSWI and their associated risks remain rarely studied. Based on a one-year passive air sampling (PAS) scheme, we investigated airborne PBDD/Fs and PCDD/Fs around a large-scale MSWI that has been operated for multi-years. Both the concentrations of PBDD/Fs and PCDD/Fs showed spatially decreasing trends with the distance away from the MSWI, confirming the influence of the MSWI on the dioxin levels in its ambient air. But its influence on PBDD/Fs was less because PBDD/Fs exhibit lower volatility and therefore lower gaseous concentrations than PCDD/Fs. Compared to the existing global data of airborne PCDD/Fs and PBDD/Fs, our data of the MSWI vicinity were at medium levels, despite PAS samples only represent the concentrations of gaseous dioxins in theory. The seasonal data suggest that meteorological conditions exerted apparent influences over the concentrations and sources of airborne dioxins around the MSWI. As for PCDD/Fs, the MSWI was diagnosed as their uppermost source, followed by local traffic and volatilization/deposition. Whereas the top three PBDD/F sources were related to PBDEs, bromophenol/bromobenzene, and traffic vehicles, respectively. The bioassay-derived TEQs based on the aryl hydrocarbon receptor activation of airborne dioxins around the MSWI were one or two orders of magnitudes higher than their concentration-based TEQs, and the corresponding carcinogenic risks at some MSWI-vicinal sites exceeded the acceptable threshold proposed by the U. S. EPA (10-6 ∼ 10-4) and deserve continuous attention.

Prevalence of substance use and mental health problems among transgender and cisgender U.S. adults: Results from a national probability sample

Transgender individuals experience numerous health disparities relative to cisgender individuals. However, most transgender-health studies have focused on convenience samples with limited generalizability. This study utilized data from the 2016-2018 TransPop Study, the first national probability sample of transgender adults (n=274) with a cisgender comparison sample (n=1162). Using multivariable logistic regression, adjusted for demographics, we compared the prevalence of hazardous drinking, problematic drug use, serious psychological distress, suicidality, and non-suicidal self-injury between transgender and cisgender individuals and among transgender men (n=78), transgender women (n=120), and transgender nonbinary individuals (n=76). Among transgender individuals, 28.2% (95%CI 21.2-35.2) and 31.2% (95%CI 23.8-38.7) reported hazardous drinking and problematic drug use, respectively; 44.4% (95% CI 35.8-53.0) reported recent suicidal ideation, 6.9% (95% CI 2.3-11.5) reported a recent suicide attempt, and 21.4% (95% CI 14.5%-28.4%) reported recent non-suicidal self-injury. In their lifetime, 81.3% (95%CI 75.1-87.5) of transgender respondents had suicidal ideation, 42.0% (95%CI 34.2-49.8) had attempted suicide, and 56.0% (95% CI 48.2-63.8) reported non-suicidal self-injury. Most (81.5%; 95%CI 75.5-87.5) had utilized formal mental health care and 25.5% (95%CI 18.5-32.4) had sought informal mental health support. There were no differences in alcohol or drug-use outcomes between transgender and cisgender adults. Compared to cisgender adults, transgender adults had higher odds of serious psychological distress (aOR=3.1; 95%CI 1.7-5.7), suicidal ideation (recent: aOR=5.1, 95%CI 2.7-9.6); lifetime: aOR=6.7, 95%CI 3.8-11.7), lifetime suicide attempts (aOR=4.4, 95%CI 2.4-8.0), and non-suicidal self-injury (recent: aOR=13.0, 95%CI 4.8-35.1); lifetime: aOR=7.6, 95%CI 4.1-14.3). Transgender nonbinary adults had the highest odds for all outcomes, including substance use outcomes. Findings from these national probability samples support those of earlier convenience-sample studies showing mental health disparities among transgender adults relative to cisgender adults, with nonbinary individuals at highest risk. These findings also highlight variations in risk across sub-groups of transgender individuals.

Respondent-Driven Sampling for Estimation of the Cumulative Lifetime Incidence of Abortion in Soweto, Johannesburg, South Africa: A Methodological Assessment

Respondent-driven sampling (RDS) is a potential strategy for addressing challenges in accurate estimation of abortion incidence, but it relies on often untested assumptions. We conducted an RDS study to estimate the cumulative lifetime incidence of abortion in Soweto, Johannesburg, South Africa (April-December 2018), to evaluate whether RDS assumptions were met, and to compare RDS estimates of incidence with estimates adjusted for employment and age based on census data. A total of 849 participants were recruited from 11 seed participants between April and December 2018. The assumption that individuals can identify target population members and the assumption of approximation of sampling with replacement was met. There were minor violations of the assumptions of seed independence from the final sample and reciprocity of ties. Assumptions of accurate degree reporting and random recruitment were not met. Failure to meet assumptions yielded a study sample with different employment characteristics than those of the target population; this could not be resolved by standard RDS methods. The RDS estimate of cumulative lifetime abortion incidence was 12.1% (95% confidence interval: 9.8, 14.3), and the employment-adjusted estimate was 16.9% (95% confidence interval: 12.8, 22.1). We caution researchers in using RDS for representative estimates of abortion incidence. Use of postsurvey weights to adjust for differences in characteristics between the sample and the target population may yield more representative results.

Examining differential success in recruitment using respondent driven sampling (RDS) in a multi-site study of gay, bisexual and other men who have sex with men

BACKGROUND

The Engage Study is a longitudinal biobehavioral cohort study of gay, bisexual and other men who have sex with men (GBM) in Toronto, Montreal, and Vancouver. Baseline data (2,449 participants) were collected from February 2017 - August 2019 using respondent-driven sampling (RDS). Recruitment in Montreal required fewer seeds, had a much shorter recruitment period, and recruited the largest sample.

METHODS

To better understand why RDS recruitment was more successful in Montreal compared to other sites, we conducted an analysis to examine RDS recruitment characteristics for GBM in each of the three study sites, explore demographic characteristics and measures of homophily, that is, the tendency of individuals to recruit other study participants who are like themselves, and compared motivations for study participation.

RESULTS

Montreal had the greatest proportion of participants over the age of 45 (29.1% in Montreal, 24.6% in Vancouver, and 21.0% in Toronto) and the highest homophily for this age group, but homophily was high across the three cities. Montreal also reported the lowest percentage of participants with an annual income greater or equal to $60,000 (7.9% in Montreal, 13.1% in Vancouver and 10.6% in Toronto), but homophily was similar across all three cities. The majority of participants indicated interest in sexual health and HIV as the main reason for participating (36.1% in Montreal, 34.7% in Vancouver, and 29.8% in Toronto). Financial interest as the main reason for participation was low (12.7% in Montreal, 10.6% in Vancouver, and 5.7% in Toronto).

CONCLUSION

Taken together, although we found some differences in study demographic characteristics and homophily scores, we were unable to fully explain the different recruitment success based on the data available. Our study underlines the fact that success of RDS implementation may vary by unknown factors, and that researchers should be proactive and flexible to account for variability.

Hidden population size estimation and diagnostics using two respondent-driven samples with applications in Armenia

Estimating the size of hidden populations is essential to understand the magnitude of social and healthcare needs, risk behaviors, and disease burden. However, due to the hidden nature of these populations, they are difficult to survey, and there are no gold standard size estimation methods. Many different methods and variations exist, and diagnostic tools are needed to help researchers assess method-specific assumptions as well as compare between methods. Further, because many necessary mathematical assumptions are unrealistic for real survey implementation, assessment of how robust methods are to deviations from the stated assumptions is essential. We describe diagnostics and assess the performance of a new population size estimation method, capture-recapture with successive sampling population size estimation (CR-SS-PSE), which we apply to data from 3 years of studies from three cities and three hidden populations in Armenia. CR-SS-PSE relies on data from two sequential respondent-driven sampling surveys and extends the successive sampling population size estimation (SS-PSE) framework by using the number of individuals in the overlap between the two surveys and a model for the successive sampling process to estimate population size. We demonstrate that CR-SS-PSE is more robust to violations of successive sampling assumptions than SS-PSE. Further, we compare the CR-SS-PSE estimates to population size estimations using other common methods, including unique object and service multipliers, wisdom of the crowd, and two-source capture-recapture to illustrate volatility across estimation methods.

Psychosocial factors that distinguish between men and women who have suicidal thoughts and attempt suicide: findings from a national probability sample of adults

BACKGROUND

Previous research has highlighted the importance of understanding which psychosocial factors distinguish between those with suicide thoughts compared to those who attempt suicide. This study aims to investigate these distinguishing factors further within an ideation-to-action framework and to explore sex differences in suicide risk.

METHODS

Participants (n = 7546, aged 16+) were from the cross-sectional Adult Psychiatric Morbidity Survey (APMS; 2014) of England. Face-to-face and self-completion questionnaires assessed lifetime suicidal ideation, lifetime suicide attempts, demographic characteristics, life experiences, social support, health and mental illness. Multinomial logistic regression examined factors differentiating between those with suicidal ideation only and suicide attempt histories (with or without suicidal ideation) in men and women.

RESULTS

Overall men were less likely to report suicidal thoughts and attempts, compared to females. More factors differentiated between suicidal thoughts and attempts in women compared to in men; these included hospital admission for mental illness, below degree level qualifications, being single and childhood adversity. In men, factors which significantly differentiated between suicidal thoughts and attempts included self-report of professional diagnosis of mental illness and childhood adversity. Higher levels of social support were associated with being in the suicidal thoughts group v. in the attempts group in men.

CONCLUSION

This study identified some key differences between men and women in factors associated with suicide attempts compared to suicidal thoughts. The findings support the use of the ideation-to-action framework to investigate sex differences in suicidal behaviour. Future research should examine the extent to which these factors are associated with suicide risk over time.

Use of COVIDTests.gov At-Home Test Kits Among Adults in a National Household Probability Sample - United States, 2022

At-home rapid antigen COVID-19 tests were first authorized by the Food and Drug Administration in late 2020 (1-3). In January 2022, the White House launched COVIDTests.gov, which made all U.S. households eligible to receive free-to-the-user at-home test kits distributed by the U.S. Postal Service (2). By May 2022, more than 70 million test kit packages had been shipped to households across the United States (2); however, how these kits were used, and which groups were using them, has not been reported. Data from a national probability survey of U.S. households (COVIDVu), collected during April-May 2022, were used to evaluate awareness about and use of these test kits (4). Most respondent households (93.8%) were aware of the program, and more than one half (59.9%) had ordered kits. Among persons who received testing for COVID-19 during the preceding 6 months, 38.3% used a COVIDTests.gov kit. Among kit users, 95.5% rated the experience as acceptable, and 23.6% reported being unlikely to have tested without the COVIDTests.gov program. Use of COVIDTests.gov kits was similar among racial and ethnic groups (42.1% non-Hispanic Black or African American [Black]; 41.5% Hispanic or Latino [Hispanic]; 34.8% non-Hispanic White [White]; and 53.7% non-Hispanic other races [other races]). Use of other home COVID-19 tests differed by race and ethnicity (11.8% Black, 44.4% Hispanic, 45.8% White, 43.8% other races). Compared with White persons, Black persons were 72% less likely to use other home test kits (adjusted relative risk [aRR] = 0.28; 95% CI = 0.16-0.50). Provision of tests through this well-publicized program likely improved use of COVID-19 home testing and health equity in the United States, particularly among Black persons. National programs to address availability and accessibility of critical health services in a pandemic response have substantial health value.

A Comprehensive Sampling Study on SARS-CoV-2 Contamination of Air and Surfaces in a Large Meat Processing Plant Experiencing COVID-19 Clusters in June 2020

OBJECTIVE

We aimed to assess SARS-CoV-2 contamination of air and surfaces to gain insight into potential occupational exposure in a large meat processing plant experiencing COVID-19 clusters. Methods: Oro-nasopharyngeal SARS-CoV-2 screening was performed in 76 workers. Environmental samples ( n = 275) including air, ventilation systems, sewage, and swabs of high-touch surfaces and workers' hands were tested for SARS-CoV-2 RNA by real-time quantitative polymerase chain reaction. Results: Twenty-seven (35.5%) of the (predominantly asymptomatic) workers tested positive with modest to low viral loads (cycle threshold ≥ 29.7). Six of 203 surface swabs, 1 of 12 personal air samples, and one of four sewage samples tested positive; other samples tested negative. Conclusions: Although one third of workers tested positive, environmental contamination was limited. Widespread SARS-CoV-2 transmission via air and surfaces was considered unlikely within this plant at the time of investigation while strict COVID-19 control measures were already implemented.

Respondent-driven sampling to recruit adolescents in Kenya

PURPOSE

Respondent-driven sampling (RDS) uses long-chain referral whereby members of the target population recruit other members. We describe the use of RDS for a mixed-methods sexual and reproductive health (SRH) study in Kisumu, Kenya.

METHODS

Initial seeds for the cross-sectional surveys were selected from adolescents aged 15-19 residing in urban informal settlements. Participants were provided up to five referral coupons to distribute.

RESULTS

Across four communities, 18 seeds were selected, 13,489 coupons distributed, and 3381 adolescents referred, yielding a 25% coupon return rate. We enrolled 3061 participants for a 23% survey rate. Median referral lag time was three days (IQR 1, 7). Demographic characteristics reached equilibrium between recruitment waves 5 to 8 in three communities, and waves 7 to 15 in the fourth.

CONCLUSIONS

Our study demonstrated that RDS is a feasible and efficient approach for recruiting a large sample of adolescents. Though our research focused on SRH, many adolescents residing in the impoverished urban environments where our study was implemented also experience food insecurity, housing instability and violence. RDS can therefore be a valuable recruitment approach for future studies to reach vulnerable adolescents and design interventions that address the variety of health-related challenges that affect this underserved population.

Sexual Assault and Behavioral Health: What Can We Learn From a Probability Sample of Young Sexual Minority Men?

BACKGROUND

Previous research indicates that young sexual minority men (YSMM) are at increased risk of experiencing sexual assault compared to their heterosexual peers. While this increased risk is documented in comparison studies, very little is known about the specific range of sexual assault experiences. The aim of this study was to investigate prevalence of sexual assault experiences and their association with depression and alcohol use for YSMM.

METHODS

In 2017 and 2018, 124 YSMM (18-24 year-olds) were recruited to participate in an online study using probability-based sampling methods, in Los Angeles, CA. Participants answered items about lifetime and recent sexual assault experiences (i.e., unwanted touching, oral rape, penetrative rape), characteristics of the coercive behaviors, recent alcohol use, and depression. Analysis of variance (ANOVAs) and multiple linear regressions investigated the relationships between sexual assault experiences and behavioral health.

RESULTS

The sample reported a range of lifetime sexual assault experiences: 70% unwanted touching and 28% penetrative rape. Fifty-five percent of the sample reported some type of recent sexual assault, with 17% reporting a recent penetrative rape. ANOVAs of the impact of different forms of sexual assault on behavior health indicated that unwanted touching was associated with higher depression and alcohol use. Further investigation of recent unwanted touching indicated that frequency is associated with depression and binge drinking. Of participants who reported experiences of unwanted touching, 61% reported it occurred while they were intoxicated.

DISCUSSION

Findings support previous evidence of high rates of sexual assault among YSMM. Further, the majority of men who reported sexual assault indicated that it occurred while they were intoxicated, suggesting that unwanted touching is occurring while men are drinking alcohol, likely in bars. The culture of gay bars may encourage nonconsensual touching during intoxication and these experiences of sexual assault have consequences (i.e., higher levels of depression and alcohol use).

HIV, sexual violence, and termination of pregnancy among adolescent and adult female sex workers in Malawi: A respondent-driven sampling study

Female Sex Workers (FSWs) are a hard-to-reach and understudied population, especially those who begin selling sex at a young age. In one of the most economically disadvantaged regions in Malawi, a large population of women is engaged in sex work surrounding predominantly male work sites and transport routes. A cross-sectional study in February and April 2019 in Nsanje district used respondent driven sampling (RDS) to recruit women ≥13 years who had sexual intercourse (with someone other than their main partner) in exchange for money or goods in the last 30 days. A standardized questionnaire was filled in; HIV, syphilis, gonorrhea, and chlamydia tests were performed. CD4 count and viral load (VL) testing occurred for persons living with HIV (PLHIV). Among 363 study participants, one-quarter were adolescents 13-19 years (25.9%; n = 85). HIV prevalence was 52.6% [47.3-57.6] and increased with age: from 14.7% (13-19 years) to 87.9% (≥35 years). HIV status awareness was 95.2% [91.3-97.4], ART coverage was 98.8% [95.3-99.7], and VL suppression 83.2% [77.1-88.0], though adolescent FSWs were less likely to be virally suppressed than adults (62.8% vs. 84.4%). Overall syphilis prevalence was 29.7% [25.3-43.5], gonorrhea 9.5% [6.9-12.9], and chlamydia 12.5% [9.3-16.6]. 72.4% had at least one unwanted pregnancy, 17.9% had at least one abortion (40.1% of which were unsafe). Half of participants reported experiencing sexual violence (SV) (47.6% [42.5-52.7]) and more than one-tenth (14.2%) of all respondents experienced SV perpetrated by a police officer. Our findings show high levels of PLHIV-FSWs engaged in all stages of the HIV cascade of care. The prevalence of HIV, other STIs, unwanted pregnancy, unsafe abortion, and sexual violence remains extremely high. Peer-led approaches contributed to levels of ART coverage and HIV status awareness similar to those found in the general district population, despite the challenges and risks faced by FSWs.

The temporal dynamics of sleep disturbance and psychopathology in psychosis: a digital sampling study

BACKGROUND

Sleep disruption is a common precursor to deterioration and relapse in people living with psychotic disorders. Understanding the temporal relationship between sleep and psychopathology is important for identifying and developing interventions which target key variables that contribute to relapse.

METHODS

We used a purpose-built digital platform to sample self-reported sleep and psychopathology variables over 1 year, in 36 individuals with schizophrenia. Once-daily measures of sleep duration and sleep quality, and fluctuations in psychopathology (positive and negative affect, cognition and psychotic symptoms) were captured. We examined the temporal relationship between these variables using the Differential Time-Varying Effect (DTVEM) hybrid exploratory-confirmatory model.

RESULTS

Poorer sleep quality and shorter sleep duration maximally predicted deterioration in psychosis symptoms over the subsequent 1-8 and 1-12 days, respectively. These relationships were also mediated by negative affect and cognitive symptoms. Psychopathology variables also predicted sleep quality, but not sleep duration, and the effect sizes were smaller and of shorter lag duration.

CONCLUSIONS

Reduced sleep duration and poorer sleep quality anticipate the exacerbation of psychotic symptoms by approximately 1-2 weeks, and negative affect and cognitive symptoms mediate this relationship. We also observed a reciprocal relationship that was of shorter duration and smaller magnitude. Sleep disturbance may play a causal role in symptom exacerbation and relapse, and represents an important and tractable target for intervention. It warrants greater attention as an early warning sign of deterioration, and low-burden, user-friendly digital tools may play a role in its early detection.

[Progress on the application of respondent-driven sampling in population size estimation]

Respondent-driven sampling (RDS) is a method of sampling specifically for hidden populations, often applied to transgender women, female sex workers, men who have sex with men, and other groups that are difficult to identify and contact because of stigma and legal constraints. However, this method is gradually applied to the general population. With the continuous improvement of RDS, studies find that the network size of RDS samples can be weighted to estimate the overall situation and population size. This article summarizes the current application progress of RDS in population size estimation and provides ideas for the development of RDS and the use of RDS to carry out relevant research.

Smartphone-based Respondent Driven Sampling (RDS): A methodological advance in surveying small or ‘hard-to-reach’ populations

Producing statistically robust profiles of small or ‘hard-to-reach’ populations has always been a challenge for researchers. Since surveying the wider population in order to capture a large enough sample of cases is usually too costly or impractical, researchers have been opting for ‘snowballing’ or ‘time-location sampling’. The former does not allow for claims to representativeness, and the latter struggles with under-coverage and estimating confidence intervals. Respondent Driven Sampling (RDS) is a method that combines snowballing sampling with an analytical algorithm that corrects for biases that arise in snowballing. For all its advantages, a major weakness of RDS has been around data collection. Traditionally done on-site, the process is costly and lengthy. When done online, it is cheaper and faster but under a serious threat from fraud, compromising data quality and validity of findings. This paper describes a real-life application of a RDS data collection system that maximizes fraud prevention while still benefiting from low cost and speedy data collection.

Smoking and quitting characteristics of Aboriginal and Torres Strait Islander women of reproductive age: findings from the Which Way? study

OBJECTIVE

To describe smoking characteristics, quitting behaviour and other factors associated with longest quit attempt and the use of nicotine replacement therapy (NRT) and stop-smoking medication (SSM) in a population of Indigenous Australian women of reproductive age.

DESIGN, SETTING AND PARTICIPANTS

A national cross-sectional survey of Aboriginal and Torres Strait Islander women aged 16-49 years who were smokers or ex-smokers was conducted online during the period July to October 2020.

MAIN OUTCOME MEASURES

Quitting experience: attempt to cut down, time since last quit attempt, longest period without smoking, attempt to cut down during last quit attempt, any use of NRT and/or SSM.

RESULTS

Most of the 428 participating women (302 [70.6%]) reported using an Aboriginal health service. Younger women (16-20-year-olds) smoked fewer cigarettes daily (24/42 [57.1%], 0-5 cigarettes per day), waited longer to smoke after waking (20/42 [47.6%], > 60 minutes after waking), and were categorised as low smoking dependency compared with those aged 35 years and over. One-third of women (153 [35.7%]) had ever used NRT and/or SSM. A greater proportion of older women (35-49-year-olds) had sustained a quit attempt for years (62/149 [45.6%]) and reported trying NRT and/or SSM (78/149 [52.4%]) than women in younger age groups. Quitting suddenly rather than gradually was significantly associated with sustained abstinence (prevalence ratio, 1.27 [95% CI, 1.10-1.48]). Among women who had never used NRT or SSM, most (219/275 [79.6%]) reported reasons for this in the category of attitudes and beliefs. NRT and SSM use was also more likely among women who were confident talking to their doctor about quitting (odds ratio, 2.50 [95% CI, 1.23-5.10]) and those who received most of their information from a health professional (odds ratio, 1.71 [95% CI, 1.11-2.63]).

CONCLUSION

Aboriginal and Torres Strait Islander women want to quit smoking and are making attempts to quit. Quitting suddenly, rather than reducing cigarette consumption, is associated with increased sustained abstinence. Health providers can enable access and uptake of NRT and/or SSM and should recognise that NRT and/or SSM use may change over time. Consistent messaging, frequent offers of smoking cessation support, and access to a range of smoking cessation supports should be provided to Aboriginal and Torres Strait Islander women to enable them to be smoke-free.

Intimate partner violence, suicidality, and self-harm: a probability sample survey of the general population in England

BACKGROUND

Intimate partner violence (IPV) is a recognised risk factor for psychiatric disorders. There is little current evidence on IPV and self-harm and suicidality, and we therefore aimed to investigate the associations between experience of lifetime and past-year IPV with suicidal thoughts, suicide attempt, and self-harm in the past year.

METHODS

We analysed the 2014 Adult Psychiatric Morbidity Survey, a cross-sectional survey of 7058 adults (aged ≥16 years) in England, which used a multistage random probability sampling design and involved face-to-face interviews. Participants were asked about experience of physical violence and sexual, economic, and emotional abuse from a current or former partner, and about suicidal thoughts, suicide attempts, and self-harm. Other adversities were recorded through an adapted version of the List of Threatening Experiences. Multivariable logistic regression models quantified associations between different indicators of lifetime and past-year IPV, with past-year non-suicidal self-harm, suicidal thoughts, and suicide attempts. All analyses were weighted.

FINDINGS

Using weighted percentages, we found that a fifth (21·4%) of 7058 adults reported lifetime experience of IPV, and that 27·2% of women and 15·3% of men had experienced IPV. Among women, 19·6% had ever experienced emotional IPV, 18·7% physical IPV, 8·5% economic IPV, and 3·7% sexual IPV, which was higher than in men (8·6%, 9·3%, 3·6%, and 0·3%, respectively). Findings for ethnicity were unclear. Lifetime prevalence of IPV was higher in those living in rented accommodation or deprived neighbourhoods. Among people who had attempted suicide in the past year, 49·7% had ever experienced IPV and 23·1% had experienced IPV in the past year (including 34·8% of women and 9·4% of men). After adjusting for demographics, socioeconomics, and lifetime experience of adversities, the odds ratio of a past-year suicide attempt were 2·82 (95% CI 1·54-5·17) times higher in those who have ever experienced IPV, compared with those who had not. Fully adjusted odds ratios for past-year self-harm (2·20, 95% CI 1·37-3·53) and suicidal thoughts (1·85, 1·39-2·46) were also raised in those who had ever experienced IPV.

INTERPRETATION

IPV is common in England, especially among women, and is strongly associated with self-harm and suicidality. People presenting to services in suicidal distress or after self-harm should be asked about IPV. Interventions designed to reduce the prevalence and duration of IPV might protect and improve the lives of people at risk of self-harm and suicide.

FUNDING

UK Prevention Research Partnership.

Women’s techniques for pleasure from anal touch: Results from a U.S. probability sample of women ages 18–93

The study purpose was to assess, in a U.S. probability sample of women, the specific ways women have discovered to experience pleasure from anal touch. Through qualitative pilot research with women that informed the development of the survey instrument used in this study, we identified three previously unnamed, but distinct, anal touch techniques that many women find pleasurable and that expand the anal sexual repertoire beyond the more commonly studied anal intercourse behaviors: Anal Surfacing, Anal Shallowing, and Anal Pairing. This study defines each technique and describes its prevalence among U.S. adult women. Weighted frequencies were drawn from the Second OMGYES Pleasure Report—a cross-sectional, online, national probability survey of 3017 American women’s (age 18–93) sexual experiences and discoveries. Participants were recruited via the Ipsos KnowledgePanel^®. Data suggest that 40% of women find ‘Anal Surfacing’ pleasurable: sexual touch by a finger, penis, or sex toy on and around the anus. Approximately 35% of women have experienced pleasure using ‘Anal Shallowing’: penetrative touch by a finger, penis, or sex toy just inside the anal opening, no deeper than a fingertip/knuckle. Finally, 40% of women make other forms of sexual touch more pleasurable using ‘Anal Pairing’: touch on or inside the anus that happens at the same time as other kinds of sexual touch such as vaginal penetration or clitoral touching. These data provide techniques that women can and do use to explore the anus as a pleasurable region for touch—which can enable women to better identify their own preferences, communicate about them and advocate for their sexual pleasure.

Implementation of respondent driven sampling in Nairobi, Kenya, for tracking key family planning indicators among adolescents and youth: lessons learnt

OBJECTIVE

Adolescents and youth constitute a significant proportion of the population in developing nations. Conventional survey methods risk missing adolescents/youth because their family planning/contraception (FP/C) behavior is hidden. Respondent-driven sampling (RDS), a modified chain-referral recruitment sampling approach, was used to reach unmarried adolescents/youth aged 15-24 in Nairobi, Kenya to measure key FP/C indicators. Seeds were selected and issued with three coupons which they used to invite their peers, male or female, to participate in the study. Referred participants were also given coupons to invite others till sample size was achieved. We report on key implementation parameters following standard RDS reporting recommendations.

RESULTS

A total of 1674 coupons were issued to generate a sample size of 1354. Coupon return rate was 82.7%. Study participants self-administered most survey questions and missing data was low. Differential enrolment by gender was seen with 56.0% of females recruiting females while 44.0% of males recruited males. In about two months, it was possible to reach the desired sample size using RDS methodology. Implementation challenges included presentation of expired coupons, recruitment of ineligible participants and difficulty recruiting seeds and recruits from affluent neighborhoods. Challenges were consistent with RDS implementation in other settings and populations. RDS can complement standard surveillance/survey approaches, particularly for mobile populations like adolescents/youth.

Everyday Discrimination and Alcohol use among Sexual Minority Adults in a U.S. National Probability Sample

Objective: Limited research assesses how sexual orientation and gender identity and expression (SOGIE)-based discrimination affects alcohol use above and beyond non-SOGIE-related discrimination and how this may differ for sexual minority subgroups. We examined if SOGIE-related discrimination is additive in affecting alcohol use above and beyond non-SOGIE-related discrimination and examined differences in alcohol use, everyday discrimination, and the attribution of discrimination by sex and sexual identity. Methods: A national probability sample of sexual minority adults in the United States was used (N = 1311, female = 56.4%). Bivariate sexual identity and sex-based differences in drinking frequency, heavy episodic drinking (HED), everyday discrimination, and the attribution of discrimination were assessed. Sexual identity and sex-stratified logistic regression models were estimated, where everyday discrimination and the attribution of discrimination predicted drinking frequency and HED. Results: Several differences by sex assigned at birth and sexual identity in drinking frequency, HED, everyday discrimination, and the attribution of discrimination were found in bivariate analyses. In logistic regression models, experiencing SOGIE-related in addition to other types of discrimination was associated with higher odds of HED only for gay males. No other associations were found for everyday discrimination or the attribution of discrimination with drinking frequency or HED. Conclusions: Findings suggest sex and sexual identity-based differences in everyday discrimination and the attribution of discrimination.

Diversity in the prevalence and correlates of extramarital sex in a probability sample of Latino adults

Individuals from different Spanish-speaking countries are often combined into a single Latino group. However, this group is diverse, with immigrants and naturalized citizens coming from multiple countries. The present study was conducted to (a) examine potential differences in the annual prevalence of extramarital sex as a function of cultural group (Mexican, Cuban, Puerto Rican, or other Latino) and nativity (born inside or outside the United States) and (b) identify explanations for any observed differences in the prevalence of extramarital sex, drawing on known correlates of extramarital sex and other psychosocial constructs that may be associated with cultural group or nativity that could account for such associations. Results from the National Latino and Asian American Study, a probability sample of Latinos in the United States, indicated that the annual prevalence of extramarital sex was significantly higher among (a) Puerto Ricans relative to Mexicans and (b) foreign-born individuals relative to those born in the United States. Probability of extramarital sex was significantly associated with marital satisfaction and frequency of religious attendance, but these variables did not account for the subgroup differences in the prevalence of extramarital sex. Marital adjustment, acculturation (English proficiency and use), enculturation (ethnic identity), and family cohesion were not significantly associated with probability of extramarital sex. Results underscore the need for continued research on understanding subgroup differences in the prevalence of extramarital sex within the diverse Latino community and identifying characteristics that account for such differences. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Effect of lockdown on mental health in Australia: evidence from a natural experiment analysing a longitudinal probability sample survey

BACKGROUND

Many studies have examined population mental health during the COVID-19 pandemic but have been unable to isolate the direct effect of lockdowns. The aim of this study was to examine changes in the mental health of Australians aged 15 years and older during the COVID-19 pandemic using a quasi-experimental design to disentangle the lockdown effect.

METHODS

We analysed data from ten annual waves (2011-20) of the longitudinal Household, Income and Labour Dynamics in Australia (HILDA) Survey to identify changes in the mental health of respondents from the pre-COVID-19 period (2011-19) to the COVID-19 period (2020). Difference-in-differences models were used to compare these changes between respondents in the state of Victoria who were exposed to lockdown at the time of the 2020 interviews (treatment group) and respondents living elsewhere in Australia (who were living relatively free of restrictions; control group). The models included state, year (survey wave), and person-specific fixed effects. Mental health was assessed using the five-item Mental Health Inventory (MHI-5), which was included in the self-complete questionnaire administered during the survey.

FINDINGS

The analysis sample comprised 151 583 observations obtained from 20 839 individuals from 2011 to 2020. The treatment group included 3568 individuals with a total of 37 578 observations (34 010 in the pre-COVID-19 and 3568 in the COVID-19 period), and the control group included 17 271 individuals with 114 005 observations (102 867 in the pre-COVID-19 and 11 138 in the COVID-19 period). Mean MHI-5 scores did not differ between the treatment group (72·9 points [95% CI 72·8-73·2]) and control group (73·2 points [73·1-73·3]) in the pre-COVID-19 period. In the COVID-19 period, decreased mean scores were seen in both the treatment group (69·6 points [69·0-70·2]) and control group (70·8 points [70·5-71·2]). Difference-in-differences estimation showed a small but statistically significant effect of lockdown on MHI-5 scores, with greater decline for residents of Victoria in 2020 than for those in the rest of Australia (difference -1·4 points [95% CI -1·7 to -1·2]). Stratified analyses showed that this lockdown effect was larger for females (-2·2 points [-2·6 to -1·7]) than for males (-0·6 [-0·8 to -0·5]), and even larger for women in couples with children younger than 15 years (-4·4 points [-5·0 to -3·8]), and for females who lived in flats or apartments (-4·1 points [-5·4 to -2·8]) or semi-detached houses, terraced houses, or townhouses (-4·8 points [-6·4 to -3·2]).

INTERPRETATION

The imposition of lockdowns was associated with a modest negative change in overall population mental health. The results suggest that the mental health effects of lockdowns differ by population subgroups and for some might have exaggerated existing inequalities in mental health. Although lockdowns have been an important public health tool in suppressing community transmission of COVID-19, more research is needed into the potential psychosocial impacts of such interventions to inform their future use.

FUNDING

US National Institutes of Health.

Precarious work among personal support workers in the Greater Toronto Area: a respondent-driven sampling study

BACKGROUND

The COVID-19 pandemic has highlighted the role of personal support workers (PSWs) in health care, as well as their work conditions. Our study aimed to understand the characteristics of the PSW workforce, their work conditions and their job security, as well as to explore the health of PSWs and the impact of precarious employment on their health.

METHODS

Our community-based participatory action research focused on PSWs in the Greater Toronto Area. We administered an online, cross-sectional survey between June and December 2020 using respondent-driven sampling. Data on sociodemographics, employment precarity, worker empowerment and health status were collected. We assessed the association between precarious employment and health using multivariable logistic regression models.

RESULTS

We contacted 739 PSWs, and 664 consented to participate. Overall, 658 (99.1%) completed at least part of the survey. Using data adjusted for our sampling approach, the participants were predominantly Black (76.5%, 95% confidence interval [CI] 68.2%-84.9%), women (90.1%, 95% CI 85.1%-95.1%) and born outside of Canada (97.4%, 95% CI 94.9%-99.9%). Most worked in home care (43.9%, 95% CI 35.2%-52.5%) or long-term care (34.5%, 95% CI 27.4%-42.0%). Although most participants had at least some postsecondary education (unadjusted proportion = 83.4%, n = 529), more than half were considered low income (55.1%, 95% CI 46.3%-63.9%). Most participants were precariously employed (86.5%, 95% CI 80.7%-92.4%) and lacked paid sick days (89.5%, 95% CI 85.8%-93.3%) or extended health benefits (74.1%, 95% CI 66.8%-81.4%). Nearly half of the participants described their health as less than very good (46.7%, 95% CI 37.9%-55.5%). Employment precarity was significantly associated with higher risk of depression (odds ratio 1.02, 95% CI 1.01-1.03).

INTERPRETATION

Despite being key members of health care teams, most PSWs were precariously employed with low wages that keep them in poverty; the poor work conditions they faced could be detrimental to their physical and mental health. Equitable strategies are needed to provide decent work conditions for PSWs and to improve their health.

Survey on Mental Health Status in Iranian Population Aged 15 and Above One Year after the Outbreak of COVID-19 Disease: A Population-Based Study

BACKGROUND

Mental disorders are the most common health problems that affect different population groups. According to the national survey in 2015 based on General Health Questionnaire-28 (GHQ-28), 23.44% of Iranians older than 15 years were suspected of having a mental disorder. The study aimed to determine the mental health status of the population over 15 years of age in the Islamic Republic of Iran, one year after the outbreak of COVID-19 in 2020.

METHODS

The population-based study was performed on 24584 individuals over 15 years of age in Iran between December and February, 2020. The GHQ-28 was completed through telephone interviews. Data were analyzed using descriptive statistics, chi-square test, independent t-test, and multiple logistic regression at 95% confidence level.

RESULTS

The results showed that the mean age of participants was 44.18±16.47 years. The prevalence of mental disorders was 29.7%. Mental disorder was associated with female gender (OR=1.195, 95% CI 1.10-1.29), 25-44 years (OR=1.206, 95% CI 1.06-1.36), urban life (OR=1.116, 95% CI 1.04-1.19), illiteracy (OR=1.286, 95% CI 1.11-1.48), being divorced (OR=1.924, 95% CI 1.50- 2.45), and unemployment (OR=1.657, 95% CI 1.40-1.94). Among the participants and their families, 14.7% and 32.3% were infected with the disease, respectively. The COVID-19 mortality rate in their families was 13.2%. The prevalence of mental disorders in infected people (40% vs. 27.3%) and bereaved families (39.6% vs. 35.3%) was more than the non-infected groups.

CONCLUSION

Our results showed that in Iran, the mental health of the general population had a rising trend compared to 2015, especially in people infected with COVID-19 and bereaved families. The observed difference may be due to the prevalence of the COVID-19 epidemic and rapid demographic, social, and economic changes in Iran. Planning to improve mental health in the mentioned population should be considered for the post COVID-19 era.

Optimum second call imputation in PPS sampling

The current study deals with imputation of item non-response in probability proportional to size (PPS) sampling. A new imputation procedure is proposed by using the known co-variance between the study variable and the auxiliary variable in the case of quantitative sensitive study variable by considering the non-response in a randomization mechanism on the second call. An empirical study is conducted at the optimum values of k_og and n_og for the relative comparisons of ratio, difference, and proposed estimators, respectively, with the Hansen-Hurwitz estimator.

The Importance of Context: An ESM Study in Forensic Psychiatry

Experience Sampling Method (ESM) is a structured diary technique assessing variations in thoughts, mood, and psychiatric symptoms in everyday life. Research has provided ample evidence for the efficacy of the use of ESM in general psychiatry but its use in forensic psychiatry has been limited. Twenty forensic psychiatric patients participated. The PsyMate™ Device emitted a signal 10 times a day on six consecutive days, at unpredictable moments. After each "beep," the patients completed ESM forms assessing current context, thoughts, positive and negative affect, and psychotic experiences. Stress was measured using the average scores of the stress related items. Compliance rate was high (85% beeps responded). Activity stress was related to more negative affect, lower positive affect, and more psychotic symptoms. This finding was restricted to moments when a team member was present; not when patients were alone or with other patients. ESM can be useful in forensic psychiatry and give insights into the relationships between symptoms and mood in different contexts. In this study activity-related stress was contextualized. These findings can be used to personalize interventions.

HIV Stigma Among a National Probability Sample of Adults with Diagnosed HIV-United States, 2018-2019

HIV stigma is a barrier to achieving the goals of the US Ending the HIV Epidemic initiative. We analyzed data from the Medical Monitoring Project (MMP) collected during 6/2018-5/2019 from 4050 US adults with diagnosed HIV. We reported national estimates of HIV stigma and assessed their associations with sociodemographic and clinical characteristics. Disclosure concerns and stigma related to negative public attitudes were common. Stigma was higher among younger age groups, women and transgender people, Black and Hispanic/Latino men and women, and Black and Hispanic/Latino men who have sex with men. Stigma was associated with lower antiretroviral therapy use and adherence, missed HIV care visits, and symptoms of depression or anxiety. The estimates presented provide a benchmark from which the nation can monitor its progress. The findings suggest the need for enhanced stigma-reduction efforts among specific groups and the importance of addressing stigma around disclosure and community attitudes.

Sex and Relationships Pre- and Early- COVID-19 Pandemic: Findings from a Probability Sample of U.S. Undergraduate Students

In the wake of the COVID-19 pandemic, most U.S. colleges closed their campuses-including residence halls-causing significant disruption to students' lives. Two waves of data were collected from undergraduate students enrolled at a large U.S. Midwestern university: Wave 1 was a confidential online survey of 4989 randomly sampled undergraduate students collected in January/February 2020; Wave 2 was collected in April/May 2020 following campus closure. Our research aimed to: (1) assess how the COVID-19 related campus closure affected college students' romantic/sexual relationships, (2) examine students' past month sexual behaviors prior to the pandemic in comparison with their sexual behaviors during campus closure, and (3) compare participants' pre-pandemic event-level sexual behaviors with those occurring during campus closure. Of 2137 participants who completed both waves (49.8% women, mean age = 20.9), 2.6% were living at home in Wave 1 compared to 71.0% at Wave 2. Of those in relationships, 14.5% experienced a breakup and 25.3% stayed in their relationship but returned home to different cities. There were no statistically significant differences in participants' prior month reports of solo masturbation or sending/receiving nude/sexy images between Waves 1 and 2; however, participation in oral, vaginal, and anal sex significantly decreased across waves. Examining participants' most recent sexual events, Wave 2 sex more often occurred with a cohabiting or relationship partner and was rated as more wanted, emotionally intimate, and orgasmic. Implications for sexual health professionals are discussed.

Investigation on spatial variability and influencing factors of drinking water iodine in Xinjiang, China

Background and objectives

Xinjiang is one of the areas in China with extremely severe iodine deficiency. The health of Xinjiang residents has been endangered for a long time. In order to provide reasonable suggestions for scientific iodine supplementation and improve the health and living standards of the people in Xinjiang, it is necessary to understand the spatial distribution of iodine content in drinking water and explore the influencing factors of spatial heterogeneity of water iodine content distribution.

Methods

The data of iodine in drinking water arrived from the annual water iodine survey in Xinjiang in 2017. The distribution of iodine content in drinking water in Xinjiang is described from three perspectives: sampling points, districts/counties, and townships/streets. ArcGIS was used for spatial auto-correlation analysis, mapping the distribution of iodine content in drinking water and visualizing the distribution of Geographically Weighted Regression (GWR) model parameter. Kriging method is used to predict the iodine content in water at non-sampling points. GWR software was used to build GWR model in order to find the factors affecting the distribution of iodine content in drinking water.

Results

There are 3293 sampling points in Xinjiang. The iodine content of drinking water ranges from 0 to 128 μg/L, the median is 4.15 μg/L. The iodine content in 78.6% of total sampling points are less than 10 μg/L, and only that in the 3.4% are more than 40 μg/L. Among 1054 towns’ water samples in Xinjiang, 88.9% of the samples’ water iodine content is less than 10 μg/L. Among the 94 studied areas, the median iodine content in drinking water in 87 areas was less than 10 μg/L, those values in 7 areas were between 10–40 μg/L, and the distribution of water iodine content in Xinjiang shows clustered. The GWR model established had found that the effects of soil type and precipitation on the distribution of iodine content in drinking water were statistically significant.

Conclusions

The iodine content of drinking water in Xinjiang is generally low, but there are also some areas which their drinking water has high iodine content. Soil type and precipitation are the factors affecting the distribution of drinking water iodine content, and are statistically significant (P<0.05).

Using large-scale respondent driven sampling to monitor the end of an HIV epidemic among persons who inject drugs in Hai Phong, Viet Nam

AIMS

To describe the use of large-scale respondent driven sampling (RDS) surveys to demonstrate the "end of an HIV epidemic" (HIV incidence < 0.5/100 person-years) among persons who inject drugs (PWID) in a middle-income country. Large sample sizes are needed to convincingly demonstrate very low incidence rates.

METHODS

4 large surveys (Ns approximately 1500 each) were conducted among PWID in Hai Phong, Vietnam in 2016-2019. Respondent driven sampling (RDS) with a modification to add snowball sampling was used for recruiting participants. HIV incidence was measured through recency testing, repeat participants across multiple surveys and in a cohort study of PWID recruited from the surveys. RDS analytics (time to equilibria and homophilies for major variables) were used to assess similarities/differences in RDS only versus RDS plus snowball recruiting. Characteristics were compared among respondents recruited through standard RDS recruitment versus through snowball sampling. An overall assessment of the robustness of RDS to modification was made when adding a snowball sampling recruitment.

RESULTS

RDS recruiting was very efficient in the first 5 weeks of each survey with approximately 180 respondents recruited per week. Recruiting then slowed considerably, and snowball sampling (permitting an individual respondent to recruit large numbers of new respondents) was added to the existing RDS recruiting. This led to recruiting within 13-14 weeks of 1383, 1451, 1444 and 1268 respondents, close to the target of 1500 respondents/survey. Comparisons of participants recruited through standard RDS method and respondents recruited through snowball methods showed very few significant differences. RDS analytics (quickly reaching equilibria, low homophilies) were favorable for both RDS recruited and total numbers of participants in each survey. DRug use and Infections in ViEtnam (DRIVE) methods have now been officially adopted in other provinces.

CONCLUSIONS

RDS appears to be quite robust with respect to adding a modest number of participants recruited through snowball sampling. Large sample sizes can provide compelling evidence for "ending an HIV epidemic" to policy makers in a PWID population in a middle income country setting.

Meaningful associations in the adolescent brain cognitive development study

The Adolescent Brain Cognitive Development (ABCD) Study is the largest single-cohort prospective longitudinal study of neurodevelopment and children's health in the United States. A cohort of n = 11,880 children aged 9-10 years (and their parents/guardians) were recruited across 22 sites and are being followed with in-person visits on an annual basis for at least 10 years. The study approximates the US population on several key sociodemographic variables, including sex, race, ethnicity, household income, and parental education. Data collected include assessments of health, mental health, substance use, culture and environment and neurocognition, as well as geocoded exposures, structural and functional magnetic resonance imaging (MRI), and whole-genome genotyping. Here, we describe the ABCD Study aims and design, as well as issues surrounding estimation of meaningful associations using its data, including population inferences, hypothesis testing, power and precision, control of covariates, interpretation of associations, and recommended best practices for reproducible research, analytical procedures and reporting of results.

Sensitive proportion in ranked set sampling

This paper considers the concomitant-based rank set sampling (CRSS) for estimation of the sensitive proportion. It is shown that CRSS procedure provides an unbiased estimator of the population sensitive proportion, and it is always more precise than corresponding sample sensitive proportion (Warner SL (1965)) that based on simple random sampling (SRS) without increasing sampling cost. Additionally, a new estimator based on ratio method is introduced using CRSS protocol, preserving the respondent’s confidentiality through a randomizing device. The numerical results of these estimators are obtained by using numerical integration technique. An application to real data is also given to support the methods.

Sampling Strategies for Internal Validation Samples for Exposure Measurement-Error Correction: A Study of Visceral Adipose Tissue Measures Replaced by Waist Circumference Measures

Statistical correction for measurement error in epidemiologic studies is possible, provided that information about the measurement error model and its parameters are available. Such information is commonly obtained from a randomly sampled internal validation sample. It is however unknown whether randomly sampling the internal validation sample is the optimal sampling strategy. We conducted a simulation study to investigate various internal validation sampling strategies in conjunction with regression calibration. Our simulation study showed that for an internal validation study sample of 40% of the main study’s sample size, stratified random and extremes sampling had a small efficiency gain over random sampling (10% and 12% decrease on average over all scenarios, respectively). The efficiency gain was more pronounced in smaller validation samples of 10% of the main study’s sample size (i.e., a 31% and 36% decrease on average over all scenarios, for stratified random and extremes sampling, respectively). To mitigate the bias due to measurement error in epidemiologic studies, small efficiency gains can be achieved for internal validation sampling strategies other than random, but only when measurement error is nondifferential. For regression calibration, the gain in efficiency is, however, at the cost of a higher percentage bias and lower coverage.

Snowball Sampling Study Design for Serosurveys Early in Disease Outbreaks

Serological surveys can provide evidence of cases that were not previously detected, depict the spectrum of disease severity, and estimate the proportion of asymptomatic infections. To capture these parameters, survey sample sizes may need to be very large, especially when the overall infection rate is still low. Therefore, we propose the use of "snowball sampling" to enrich serological surveys by testing contacts of infected persons identified in the early stages of an outbreak. For future emerging pandemics, this observational study sampling design can answer many key questions, such as estimation of the asymptomatic proportion of all infected cases, the probability of a given clinical presentation for a seropositive individual, or the association between characteristics of either the host or the infection and seropositivity among contacts of index individuals. We provide examples, in the context of the coronavirus disease 2019 (COVID-19) pandemic, of studies and analysis methods that use a snowball sample and perform a simulation study that demonstrates scenarios where snowball sampling can answer these questions more efficiently than other sampling schemes. We hope such study designs can be applied to provide valuable information to slow the present pandemic as it enters its next stage and in early stages of future pandemics.