Structural zeroes and zero-inflated models

Factors determining antenatal care utilization among mothers of deceased perinates in Ethiopia

Introduction

Receiving adequate antenatal care (ANC) had an integral role in improving maternal and child health outcomes. However, several factors influence the utilization of ANC from the individual level up to the community level factors. Thus, this study aims to investigate factors that determine ANC service utilization among mothers of deceased perinate using the proper count regression model.

Method

Secondary data analysis was performed on perinatal death surveillance data. A total of 3,814 mothers of deceased perinates were included in this study. Hurdle Poisson regression with a random intercept at both count-and zero-part (MHPR.ERE) model was selected as a best-fitted model. The result of the model was presented in two ways, the first part of the count segment of the model was presented using the incidence rate ratio (IRR), while the zero parts of the model utilized the adjusted odds ratio (AOR).

Result

This study revealed that 33.0% of mothers of deceased perinates had four ANC visits. Being in advanced maternal age [IRR = 1.03; 95CI: (1.01-1.09)], attending primary level education [IRR = 1.08; 95 CI: (1.02-1.15)], having an advanced education (secondary and above) [IRR = 1.14; 95 CI: (1.07-1.21)] and being resident of a city administration [IRR = 1.17; 95 CI: (1.05-1.31)] were associated with a significantly higher frequency of ANC visits. On the other hand, women with secondary and above education [AOR = 0.37; 95CI: (0.26-0.53)] and women who live in urban areas [AOR = 0.42; 95 CI: (0.33-0.54)] were less likely to have unbooked ANC visit, while women who resided in pastoralist regions [AOR = 2.63; 95 CI: (1.02-6.81)] were more likely to have no ANC visit.

Conclusion

The uptake of ANC service among mothers having a deceased perinate was determined by both individual (maternal age and educational status) and community (residence and type of region) level factors. Thus, a concerted effort is needed to improve community awareness through various means of communication by targeting younger women. Furthermore, efforts should be intensified to narrow down inequalities observed in ANC service provision due to the residence of the mothers by availing necessary personnel and improving the accessibility of service in rural areas.

Job satisfaction and job security as moderators in the relationships among job demands, musculoskeletal symptoms, and work performance

PURPOSE

This study examined whether job satisfaction and job security moderate the path from physical demands and job strain to impaired work performance via musculoskeletal symptoms in the upper extremities (MSUE). Moderation effects on five paths were examined: (1) from job strain to MSUE; (2) from job strain to work performance; (3) from physical demands to MSUE; (4) from physical demands to work performance; (5) from MSUE to work performance.

METHODS

This was a cross-sectional study of 669 full-time workers from 9 manufacturing and 3 healthcare facilities. Data were collected via health interviews, on-site physical exposure assessments, and computation of the Strain Index by ergonomists, and self-administered questionnaires on psychosocial factors. Structural equation modeling and zero-inflated negative binomial regression analysis were performed to examine the moderation effect on each path.

RESULTS

Job satisfaction moderated the relationship between MSUE and impaired work performance (B = - 0.09, 95% CI: - 0.15, - 0.04) and job security moderated the relationship between physical demands and MSUE (B = - 0.64, 95% CI: - 1.17, - 0.11). Interaction between job satisfaction and MSUE was significant on both the occurrence (OR: 0.92, 95% CI: 0.87, 0.97) and the degrees of impaired work performance (mean ratio: 0.99, 95% CI: 0.97, 0.99), while the interaction between job security and physical demands was significant only on the degrees of MSUE (mean ratio: 0.94, 95% CI: 0.89, 0.99).

CONCLUSION

Job satisfaction and job security can, respectively, mitigate the adverse impacts of working with MSUE and physical demands on work performance. Workplace interventions to improve workers' job satisfaction and job security can contribute to their musculoskeletal health and work performance.

Gay Community Involvement and Condomless Anal Sex Among Sexual Minority Men in the USA

Sexual minority men (SMM) remain disproportionately burdened by sexually transmitted infections. Although gay community involvement has been theorized to be protective against many negative health outcomes, research examining the association between community involvement and condomless anal sex (CAS) has yielded conflicting results. The current study, conducted between 2018-2020, examined whether the importance one places on various aspects of community involvement was associated with CAS among a sample of young adult SMM aged 18-34 years with body image concerns (N = 180). Gay community involvement was measured using the Importance of Gay Community Scale, and the results of an exploratory factor analysis indicated the presence of two factors: "social activism" and "going out/nightlife." A zero-inflated Poisson regression was conducted to examine the association between gay "social activism," "going out/nightlife," and their interaction with the number of CAS partners. Upon examining a significant interaction, "social activism" had a protective effect against CAS at low levels of "going out/nightlife," but this effect was non-significant at higher levels. These results suggest that encouraging gay community involvement through activism could be effective at reducing CAS and addressing the health disparity that exists within this population.

Stretching the Habitat Envelope: Insectivorous Bat Guilds Can Use Rubber Plantations, but Need Understorey Vegetation and Forest Buffers

Effects of land-cover change on insectivorous bat activity can be negative, neutral or positive, depending on foraging strategies of bats. In tropical agroforestry systems with high bat diversity, these effects can be complex to assess. We investigated foraging habitat use by three insectivorous bat guilds in forests and rubber plantations in the southern Western Ghats of India. Specifically, we monitored acoustic activity of bats in relation to (1) land-cover types and vegetation structure, and (2) plantation management practices. We hypothesized that activity of open-space aerial (OSA) and edge-space aerial (ESA) bat guilds would not differ; but narrow-space, flutter-detecting (NSFD) bat guild activity would be higher, in structurally heterogeneous forest habitats than monoculture rubber plantations. We found that bat activity of all guilds was highest in areas with high forest cover and lowest in rubber plantations. Higher bat activity was associated with understorey vegetation in forests and plantations, which was expected for NSFD bats, but was a surprise finding for OSA and ESA bats. Within land-cover types, open areas and edge-habitats had higher OSA and ESA activity respectively, while NSFD bats completely avoided open habitats. In terms of management practices, intensively managed rubber plantations with regular removal of understorey vegetation had the lowest bat activity for all guilds. Intensive management can undermine potential ecosystem services of insectivorous bats (e.g., insect pest-control in rubber plantations and surrounding agro-ecosystems), and magnify threats to bats from human disturbances. Low-intensity management and maintenance of forest buffers around plantations can enable persistence of insectivorous bats in tropical forest-plantation landscapes.

Can citizen pressure influence politicians' communication about climate change? Results from a field experiment

Urgent reductions in greenhouse gas emissions depend on governments implementing and enforcing rigorous climate policy. Individuals in democracies seeking to persuade government officials to reduce greenhouse gas emissions can take steps such as voting, protesting, and contacting officials directly, but it is unclear how effective each of these actions is in changing the behavior of elected officials. Here we take advantage of the public nature of social media to evaluate the actual efficacy of climate campaign emails using an original, real-world experiment where 335 Members of Canadian Parliament were asked by constituents to post a pro-climate message to their Twitter account. Only one Member of Parliament posted the exact text suggested by the campaign. After scraping and coding 18,776 tweets, we first find no evidence that a public health messaging frame is more effective than a standard environmental frame in eliciting pro-climate posts. Furthermore, we find only a marginally significant relationship between volume of constituent contact and increased pro-climate tweeting from Members of Parliament. Follow-up interviews with political staffers suggest that analog alternatives may be more effective than campaign emails in some cases. Interview findings also reveal that some offices receive low levels of constituent communication on climate change, indicating that increased pressure from constituents could still be consequential.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10584-021-03215-9.

Interpreting COVID-19 deaths among nursing home residents in the US: The changing role of facility quality over time

A report published last year by the Centers for Medicare & Medicaid Services (CMS) highlighted that COVID-19 case counts are more likely to be high in lower quality nursing homes than in higher quality ones. Since then, multiple studies have examined this association with a handful also exploring the role of facility quality in explaining resident deaths from the virus. Despite this wide interest, no previous study has investigated how the relation between quality and COVID-19 mortality among nursing home residents may have changed, if at all, over the progression of the pandemic. This understanding is indeed lacking given that prior studies are either cross-sectional or are analyses limited to one specific state or region of the country. To address this gap, we analyzed changes in nursing home resident deaths across the US between June 1, 2020 and January 31, 2021 (n = 12,415 nursing homes X 8 months) using both descriptive and multivariable statistics. We merged publicly available data from multiple federal agencies with mortality rate (per 100,000 residents) as the outcome and CMS 5-star quality rating as the primary explanatory variable of interest. Covariates, based on the prior literature, consisted of both facility- and community-level characteristics. Findings from our secondary analysis provide robust evidence of the association between nursing home quality and resident deaths due to the virus diminishing over time. In connection, we discuss plausible reasons, especially duration of staff shortages, that over time might have played a critical role in driving the quality-mortality convergence across nursing homes in the US.

Assessing the Influence of Community Health Worker Support on Early Antiretroviral Therapy Adherence, Anticipated Stigma, and Mental Health Among People Living with HIV in Tanzania

In many low- and middle-income countries, community health workers (CHWs) support multiple aspects of HIV care, including patient education and counseling, adherence support, and re-engaging patients lost to care. In Tanzania, the Community-Based HIV Services program is a nationwide cohort of CHWs supporting HIV care engagement. We enrolled a prospective cohort study of 80 people initiating HIV care at two Tanzanian clinics and conducted baseline and 3-month follow-up assessments to examine the potential influence of CHW support and other factors on patient early self-reported medication adherence, depression, anxiety, attitudes about medication, and HIV stigma. The vast majority of participants reported maintaining strong antiretroviral therapy (ART) adherence during the study and endorsed beliefs that ART is beneficial for them. However, there was high occurrence of likely depression and anxiety disorders in the study sample. Patient contact with CHWs at the clinic was unexpectedly low; fewer than two-thirds of participants were informed about the CHW program and fewer than one-third ever met with a CHW. Among participants who met with a CHW, there was mixed feedback about the helpfulness of the program, and contact with a CHW did not improve medication adherence at 3-month follow-up. Male participants, those with likely depression, and those who lived further from the clinic were significantly more likely to experience adherence challenges. The study findings indicate that CHWs are currently underutilized to provide patient support and may not be producing observable benefits to patients in this setting, representing a missed opportunity to address patient challenges, including depression and anxiety.

Statistical models for analyzing count data: predictors of length of stay among HIV patients in Portugal using a multilevel model

BACKGROUND

This study offers a comprehensive approach to precisely analyze the complexly distributed length of stay among HIV admissions in Portugal.

OBJECTIVE

To provide an illustration of statistical techniques for analysing count data using longitudinal predictors of length of stay among HIV hospitalizations in Portugal.

METHOD

Registered discharges in the Portuguese National Health Service (NHS) facilities Between January 2009 and December 2017, a total of 26,505 classified under Major Diagnostic Category (MDC) created for patients with HIV infection, with HIV/AIDS as a main or secondary cause of admission, were used to predict length of stay among HIV hospitalizations in Portugal. Several strategies were applied to select the best count fit model that includes the Poisson regression model, zero-inflated Poisson, the negative binomial regression model, and zero-inflated negative binomial regression model. A random hospital effects term has been incorporated into the negative binomial model to examine the dependence between observations within the same hospital. A multivariable analysis has been performed to assess the effect of covariates on length of stay.

RESULTS

The median length of stay in our study was 11 days (interquartile range: 6-22). Statistical comparisons among the count models revealed that the random-effects negative binomial models provided the best fit with observed data. Admissions among males or admissions associated with TB infection, pneumocystis, cytomegalovirus, candidiasis, toxoplasmosis, or mycobacterium disease exhibit a highly significant increase in length of stay. Perfect trends were observed in which a higher number of diagnoses or procedures lead to significantly higher length of stay. The random-effects term included in our model and refers to unexplained factors specific to each hospital revealed obvious differences in quality among the hospitals included in our study.

CONCLUSIONS

This study provides a comprehensive approach to address unique problems associated with the prediction of length of stay among HIV patients in Portugal.

A Brief Clinic-Based Intervention to Reduce Alcohol Misuse and Sexual Risk Behavior in Young Women: Results from an Exploratory Clinical Trial

This exploratory trial determined the feasibility, acceptability, and preliminary efficacy of a brief intervention (BI), supplemented with text messaging and a curated Web site, on alcohol use and sexual risk behavior among young women. Young women seeking care at a reproductive health clinic were screened for alcohol misuse and sexual risk behavior. Those who screened positive and who agreed to participate (N = 48; M = 22.67 years) were randomized to either (a) a brief in-person session during which personalized feedback regarding alcohol use and sexual risk taking was provided and discussed, or (b) a control condition. Feasibility was assessed by recruitment and retention rates. Acceptability was assessed with participant ratings of their intervention. Efficacy was measured using self-reported alcohol use and sexual behavior at baseline and during a 3-month follow-up. We supplemented the quantitative data with qualitative data from semi-structured interviews. Feasibility data indicated that 64% of eligible women agreed to participate, 74% of eligible women were enrolled, and 86% of enrolled women were retained through follow-up. Acceptability data showed that women who received the BI reported strong satisfaction with their intervention (M = 4.65 vs. 3.98 on a five-point scale) and also reported that text messaging was helpful (M = 4.73 on a seven-point scale) and acceptable (M = 5.27 on a seven-point scale). Qualitative data provided additional support for BI feasibility and acceptability. Efficacy data showed that women in both conditions reduced alcohol use and sexual risk behavior over time; women who received the BI reduced their maximum daily alcohol intake more than controls (BI from 7.68 to 4.82 standard drinks vs. control from 6.48 to 5.65; Wald χ² = 4.93, p < .05). Women in the BI reported fewer occasions of condomless sex (median = 2.50) than controls (median = 5.00) at the follow-up, but this difference was not statistically significant (OR = 0.61, 95% CI [0.32, 1.15]). A brief intervention, supplemented with text messaging and a Web site, that targeted alcohol use and sexual behavior was feasible and acceptable to young women and led to lower levels of alcohol misuse and sexual risk behavior.

Modelling the number of antenatal care visits in Bangladesh to determine the risk factors for reduced antenatal care attendance

The existence of excess zeros in the distribution of antenatal care (ANC) visits in Bangladesh raises the research question of whether there are two separate generating processes in taking ANC and the frequency of ANC. Thus the main objective of this study is to identify a proper count regression model for the number of ANC visits by pregnant women in Bangladesh covering the issues of overdispersion, zero-inflation, and intra-cluster correlation with an additional objective of determining risk factors for ANC use and its frequency. The data have been extracted from the nationally representative 2014 Bangladesh Demographic and Health Survey, where 22% of the total 4493 women did not take any ANC during pregnancy. Since these zero ANC visits can be either structural or sampling zeros, two-part zero-inflated and hurdle regression models are investigated along with the standard one-part count regression models. Correlation among response values has been accounted for by incorporating cluster-specific random effects in the models. The hurdle negative binomial regression model with cluster-specific random intercepts in both the zero and the count part is found to be the best model according to various diagnostic tools including likelihood ratio and uniformity tests. The results show that women who have poor education, live in poor households, have less access to mass media, or belong to the Sylhet and Chittagong regions are less likely to use ANC and also have fewer ANC visits. Additionally, women who live in rural areas, depend on family members’ decisions to take health care, and have unintended pregnancies had fewer ANC visits. The findings recommend taking both cluster-specific random effects and overdispersion and zero-inflation into account in modelling the ANC data of Bangladesh. Moreover, safe motherhood programmes still need to pay particular attention to disadvantaged and vulnerable subgroups of women.

Improved Monte Carlo methods for estimating confidence intervals for eleven commonly used health disparity measures

Health disparities are commonplace and of broad interest to policy makers, but are also challenging to measure and communicate. The Health Disparity Calculator software (HD*Calc, v1.2.4) offers Monte Carlo simulation (MCS)-based confidence interval (CI) estimation of eleven disparity measures. The MCS approach provides accurate CI estimation, except when data are scarce (e.g., rare cancers). To address sparse data challenges to CI estimation, we propose two solutions: 1) employing the gamma distribution in the MCS and 2) utilizing a zero-inflated Poisson estimate for Poisson sampling in simulation experiments. We evaluate each solution through simulation studies using female breast, female brain, lung, and cervical cancer data from the Surveillance, Epidemiology, and End Results (SEER) program. We compare the coverage probabilities (CPs) of eleven health disparity measures based on simulated datasets. The truncated normal distribution implemented in the MCS with the standard Poisson samples (the default setting of HD*Calc) leads to less-than-optimal coverage probabilities (<95%). When both the gamma distribution and the estimated mean from the zero-inflated Poisson are used for the MCS, the coverage probabilities are close to the nominal level of 95%. Simulation studies also demonstrate that collapsing age categories for better CI estimation is not a pragmatic solution.

Specific MHC class I supertype associated with parasite infection and color morph in a wild lizard population

The major histocompatibility complex (MHC) is a large gene family that plays a central role in the immune system of all jawed vertebrates. Nonavian reptiles are underrepresented within the MHC literature and little is understood regarding the mechanisms maintaining MHC diversity in this vertebrate group. Here, we examined the relative roles of parasite-mediated selection and sexual selection in maintaining MHC class I diversity of a color polymorphic lizard. We discovered evidence for parasite-mediated selection acting via rare-allele advantage or fluctuating selection as ectoparasite load was significantly lower in the presence of a specific MHC supertype (functional clustering of alleles): supertype four. Based on comparisons between ectoparasite prevalence and load, and assessment of the impact of ectoparasite load on host fitness, we suggest that supertype four confers quantitative resistance to ticks or an intracellular tickborne parasite. We found no evidence for MHC-associated mating in terms of pair genetic distance, number of alleles, or specific supertypes. An association was uncovered between supertype four and male throat color morph. However, it is unlikely that male throat coloration acts as a signal of MHC genotype to conspecifics because we found no evidence to suggest that male throat coloration predicts male mating status. Overall, our results suggest that parasite-mediated selection plays a role in maintaining MHC diversity in this population via rare-allele advantage and/or fluctuating selection. Further work is required to determine whether sexual selection also plays a role in maintaining MHC diversity in agamid lizards.

The effect of N-acetylcysteine on alcohol use during a cannabis cessation trial

BACKGROUND

Individuals with alcohol use disorder (AUD) do not always respond to currently available treatments, and evaluation of new candidate pharmacotherapies is indicated. N-acetylcysteine (NAC), an over-the-counter supplement, has shown promise in treating a variety of substance use disorders, but little research has evaluated its merits as a treatment for AUD. This secondary analysis from the National Drug Abuse Treatment Clinical Trials Network examined the effects of NAC versus placebo on alcohol use among participants with cannabis use disorder (CUD) enrolled in a 12-week, multi-site cannabis cessation trial.

METHODS

Participants (N = 302, ages 18-50) were randomized to double-blind NAC (1200 mg, twice daily) or placebo. Neither alcohol use nor desire for alcohol cessation were requirements for participation. Participants that returned for at least one treatment visit and had recorded alcohol use data (i.e., total drinks per week, drinking days per week, and binge drinking days per week) were included in the analysis (n = 277).

RESULTS

Compared to the placebo group, participants in the NAC group had increased odds of between-visit alcohol abstinence [OR = 1.37; 95% CI = 1.06-1.78; p = 0.019], fewer drinks per week [RR = 0.67; 95% CI = 0.48-0.99; p = 0.045], and fewer drinking days per week [RR = 0.69; 95% CI = 0.51-0.92; p = 0.014]. Changes in concurrent cannabis use amounts were not correlated to any of the alcohol use variables.

DISCUSSION

These findings indicate that NAC may be effective at reducing consumption of alcohol by ∼30% among treatment-seeking adults with CUD, suggesting a need for further trials focused on the effects of NAC on alcohol consumption among individuals seeking treatment for AUD.

Zero-inflated multiscale models for aggregated small area health data

It is our primary focus to study the spatial distribution of disease incidence at different geographical levels. Often, spatial data are available in the form of aggregation at multiple scale levels such as census tract, county, state, and so on. When data are aggregated from a fine (e.g. county) to a coarse (e.g. state) geographical level, there will be loss of information. The problem is more challenging when excessive zeros are available at the fine level. After data aggregation, the excessive zeros at the fine level will be reduced at the coarse level. If we ignore the zero inflation and the aggregation effect, we could get inconsistent risk estimates at the fine and coarse levels. Hence, in this paper, we address those problems using zero inflated multiscale models that jointly describe the risk variations at different geographical levels. For the excessive zeros at the fine level, we use a zero inflated convolution model, whereas we consider a regular convolution model for the smoothed data at the coarse level. These methods provide a consistent risk estimate at the fine and coarse levels when high percentages of structural zeros are present in the data.

Recommendations for harmonization of data collection and analysis of developmental neurotoxicity endpoints in regulatory guideline studies: Proceedings of workshops presented at Society of Toxicology and joint Teratology Society and Neurobehavioral Teratology Society meetings

The potential for developmental neurotoxicity (DNT) of environmental chemicals may be evaluated using specific test guidelines from the US Environmental Protection Agency or the Organisation for Economic Cooperation and Development (OECD). These guidelines generate neurobehavioral, neuropathological, and morphometric data that are evaluated by regulatory agencies globally. Data from these DNT guideline studies, or the more recent OECD extended one-generation reproductive toxicity guideline, play a pivotal role in children's health risk assessment in different world areas. Data from the same study may be interpreted differently by regulatory authorities in different countries resulting in inconsistent evaluations that may lead to inconsistencies in risk assessment decisions internationally, resulting in regional differences in public health protection or in commercial trade barriers. These issues of data interpretation and reporting are also relevant to juvenile and pre-postnatal studies conducted more routinely for pharmaceuticals and veterinary medicines. There is a need for development of recommendations geared toward the operational needs of the regulatory scientific reviewers who apply these studies in risk assessments, as well as the scientists who generate DNT data sets. The workshops summarized here draw upon the experience of the authors representing government, industry, contract research organizations, and academia to discuss the scientific issues that have emerged from diverse regulatory evaluations. Although various regulatory bodies have different risk management decisions and labeling requirements that are difficult to harmonize, the workshops provided an opportunity to work toward more harmonized scientific approaches for evaluating DNT data within the context of different regulatory frameworks. Five speakers and their coauthors with neurotoxicology, neuropathology, and regulatory toxicology expertise discussed issues of variability, data reporting and analysis, and expectations in DNT data that are encountered by regulatory authorities. In addition, principles for harmonized evaluation of data were suggested using guideline DNT data as case studies.

Alcohol use during a trial of N-acetylcysteine for adolescent marijuana cessation

AIMS

Current adolescent alcohol treatments have modest effects and high relapse rates. Evaluation of novel pharmacotherapy treatment is warranted. N-acetylcysteine (NAC), an over-the-counter antioxidant supplement with glutamatergic properties, is a promising treatment for marijuana cessation in adolescents; however, its effects on adolescent drinking have not been examined. To that end, this secondary analysis evaluated: (1) the effect of NAC vs. placebo on alcohol use over an eight-week adolescent marijuana cessation trial and (2) the role of marijuana cessation and reduction on subsequent alcohol use.

METHODS

Marijuana-dependent adolescents (ages 15-21; N=116) interested in treatment were randomized to NAC 1200mg or matched placebo twice daily for eightweeks. Participants were not required to be alcohol users or interested in alcohol cessation to qualify.

RESULTS

There were no demographic or baseline alcohol use differences between participants randomized to NAC vs. placebo (ps>0.05). Of the 89 participants returning for ≥one visit following randomization, 77 reported ≥one alcoholic drink in the 30days prior to study entry and averaged 1.3 (SD=1.4) binge drinking days per week. During treatment, less marijuana use (measured via urine cannabinoid levels) was associated with less alcohol use in the NAC-treated group but not in the placebo-treated group (p=0.016).

CONCLUSIONS

There was no evidence of compensatory alcohol use during marijuana treatment. In fact, in the NAC group, lower levels of marijuana use were associated with less alcohol use, suggesting NAC effects may generalize to other substances and could be useful in decreasing adolescent alcohol use. NAC trials specifically focused on alcohol-using adolescents are warranted.