Ashok Chaurasia

• Ph.D. (Statistics)
• Professor (Assistant) at University of Waterloo

Objective and ApproachUnderstanding vaccine hesitancy among distinct communities is crucial to ensuring equitable uptake of vaccination. The objective was to examine the influence of psychological antecedents of vaccine uptake, known as the “5Cs”, on COVID-19 vaccination among Métis Nation of Ontario (MNO) citizens. The Métis people are one of thre...

We explored longitudinal associations between religion/spirituality (R/S) Salience and R/S Attendance, and colorectal cancer screening, among adults aged ≥ 50 years in Alberta, Canada. R/S Salience was not statistically significantly associated with colorectal cancer screening (adjusted odds ratio [aOR]: 1.06, 95% confidence interval [CI] 0.88–1.28...

Objective The purpose of this systematic review is to assess the impact of assistive devices on the life satisfaction of (Research Question 1), and informal caregiving hours received by (Research Question 2), community-dwelling older adults (≥ 65 years). Methods We searched CINAHL, MEDLINE, and Scopus from database inception to March 2022. For eac...

Model Selection is a ubiquitous task in the model building process that seeks a parsimonious model to explain patterns in data. Bayesian Information Criteria (BIC) is one such tool that is used in applications for its property of consistency, where this term is traditionally synonymous with asymptotic consistency. This article introduces the concep...

Objective: We wanted to determine whether the biological embedding of perceived psychosocial stress could be observed within a sample of Canadian firefighters. Methods: We collected sociodemographic and general health-related information from 58 firefighters. As well, measures of work-related and general-life psychosocial stress, perceived socia...

We investigated the association between religious participation and executive function in a national sample of Canadian adults aged 45 to 85 years. Executive function scores were aggregated from six neurocognitive tests. We regressed the aggregate scores onto religious participation and controlled for numerous covariates. The analyses were stratifi...

Breast cancer is the leading cause of cancer-related mortality among women. Screening permits the early detection and treatment of malignancies, thereby reducing mortality. A woman’s religiosity and spirituality (R/S) may facilitate screening through encouragement of healthy behaviors. Population-level data from Alberta’s Tomorrow Project (ATP) wer...

Background Despite the benefits of physical activity (PA), the majority of Canadian youth are falling short of the recommended 60 min of moderate-to-vigorous physical activity (MVPA) per day. School-based physical activity programs such as intramurals, are important opportunities for youth to be physically active. There is limited evidence availabl...

It is currently unknown which attitude-based profiles are associated with symptom checker use for self-triage. We sought to identify, among university students, attitude-based latent classes (population profiles) and the association between latent classes with the future use of symptom checkers for self-triage. Informed by the Technology Acceptance...

Scales currently validated to assess severity of chronic physical conditions in children are not well suited for limited-resource settings as they lack ease of use and interpretation. This study assessed the validity of the Global Assessment of Severity of Illness (GASI), a single-item scale designed for quick and simple assessment of illness sever...

To investigate the association between religious participation and memory in persons aged 45–85 years. Using the Canadian Longitudinal Study on Aging, frequency of religious participation was measured from “daily” to “never”; immediate and delayed recall memory were assessed with the Rey Auditory Verbal Learning Test. We regressed memory onto relig...

Missing values in data impede the task of inference for population parameters of interest. Multiple Imputation (MI) is a popular method for handling missing data since it accounts for the uncertainty of missing values. Inference in MI involves combining point and variance estimates from each imputed dataset via Rubin’s rules. A sufficient condition...

Introduction Intramurals in schools may encourage physical activity among youth. Schools are continuously making changes to these intramurals, yet it is not well understood how these changes impact youth physical activity. The main objective of this research was to examine if changes in the number of intramurals were associated with youth physical...

(1) School-based physical activity programs such as intramurals provide youth with inclusive opportunities to be physically active, yet we know little about how types of intramurals (e.g., team and individual sports) may contribute to youth MVPA. This research aims to evaluate how real-world changes in types of intramurals available in schools impa...

Objective Symptom checkers are potentially beneficial tools during pandemics. To increase the use of the platform, perspectives of end users must be gathered. Our objectives were to understand the perspectives and experiences of young adults related to the use of symptom checkers for assessing COVID-19-related symptoms and to identify areas for imp...

Introduction: Few studies have assessed the relationship between chronic disease risk behaviours and body mass index (BMI) in a longitudinal, sex/gender-specific context. This study used gender-specific analyses to assess the extent to which chronic disease risk behaviour latent classes are associated with BMI and weight status at follow-up. Meth...

BACKGROUND Young adults often browse the Internet for self-triage and diagnosis; however, more recently, sophisticated digital platforms such as symptom checkers have become pervasive albeit little is known about their use. OBJECTIVE To understand young adults’ (between 18 and 34 years old) perspectives on the use of the Google search engine versu...

Background Young adults often browse the internet for self-triage and diagnosis. More sophisticated digital platforms such as symptom checkers have recently become pervasive; however, little is known about their use. Objective The aim of this study was to understand young adults’ (18-34 years old) perspectives on the use of the Google search engin...

Introduction Over one in eight Canadians is affected by a foodborne infection annually; however, the long-term consequences, including the risks and costs of sequelae, are unclear. We aim to estimate the health burden and direct costs of 14 infections commonly transmitted by food, considering the acute illness and subsequent sequelae and mortality,...

Introduction To assess the association between perceived susceptibility of developing cancer and being screened via sigmoidoscopy/colonoscopy and prostate-specific antigen, respectively. Methods Participants aged 35–69, who resided in Alberta, Canada, were enrolled into the study between 2000 and 2008. We used general linear mixed models, adjusted...

The purpose of this study was to identify gender differences in the association between bullying and Body Mass Index (BMI) longitudinally. Longitudinal data (2013–2015) from 4510 youth (Ontario, Canada) were used to model BMI with consecutive bullying status prospectively, adjusting for previously identified gender-specific health risk behaviour la...

Background: Research on the factors associated with dialysis withdrawal in dialysis patients has been limited. Authors have used different definitions for dialysis withdrawal, resulting in inconsistent findings. The objective of this study was to determine the factors associated with dialysis withdrawal in dialysis patients.Methods: This retrospect...

Background & objectives Due to the dangers of the construction industry, leading and lagging safety indicators have been developed to measure safety performance and prevent injury. It is important to examine the effect of leading indicators on a project level to better understand how leading indicator data can be used by company management. This st...

Objectives: Cross-sectional data from Alberta's Tomorrow Project (ATP) were used to assess the association between perceived susceptibility (PS) to developing cancer and mammography screening behaviour. Study design: Cross-sectional study. Methods: ATP participants between 35 and 70 years of age who reported being free of chronic conditions we...

Background: The school environment has the potential to influence student body mass index (BMI) through programs and policies. Our objective was to examine the effect of modifying obesity-related school policies and programs on youths' BMI trajectories. Methods: Obesity-related school policies and programs related to physical activity and health...

This paper sought to examine chronic disease risk behaviour latent classes and their association with Body Mass Index (BMI), assessing for gender differences. Participants were youth (n = 116,086; grades 9-12) enrolled in the COMPASS study (Ontario, Canada) during 2013, 2014, 2015. Multilevel latent class analysis was used to identify underlying, h...

BACKGROUND Artificially-intelligent self-diagnosing digital platforms are becoming widely available and used by the general population. Little is known about the body of knowledge surrounding this technology. OBJECTIVE The objectives of this scoping review are: 1) to systematically map the extent and nature of the literature and topic areas pertai...

Background: Self-diagnosis is the process of diagnosing or identifying a medical condition in oneself. Artificially intelligent digital platforms for self-diagnosis are becoming widely available and are used by the general public; however, little is known about the body of knowledge surrounding this technology. Objective: The objectives of this...

Background School nutrition policies can encourage restrictions in sugar-sweetened beverage (SSB) availability in school food outlets in order to discourage students’ SSB intake. The main objective was to examine how beverage availability in school vending machines changes over three school years across schools in distinct school nutrition policy c...

Background: Youth may use a variety of tobacco products and e-cigarettes. However, there is a lack of evidence for the combinations of tobacco products and e-cigarettes commonly used by youth in Canada and whether youth from different usage classes share similar characteristics. Methods: A cohort of 9th grade students from Ontario, Canada was id...

Objectives To describe the proportion of residents receiving rehabilitation in long‐term care (LTC) homes, and scores on activities of daily living (ADL) and falls quality indicators (QIs) before and after change from fee‐for‐service to an episode of care model; and to evaluate the effect of the change on the QIs. Data Sources Secondary data were...

Objective To examine associations between Canadian adolescents’ sugar-sweetened beverage (SSB) consumption and several school food environment characteristics, and to investigate differences in these characteristics between schools in provinces with voluntary (Alberta) v . mandatory (Ontario) provincial school nutrition policies. Design We used a...

Objectives: To examine whether several food purchasing behaviors (ie, sources of meals or snacks) are associated with adolescents' sugar-sweetened beverage (SSB) consumption and whether these associations vary by province. Design: Cross-sectional observational study. Setting: Alberta and Ontario, Canada. Participants: Secondary school studen...

Background Youth are engaging in multiple risky behaviours, increasing their risk of overweight, obesity, and related chronic diseases. The objective of this study was to examine the effect of engaging in unique clusters of unhealthy behaviours on youths’ body mass index (BMI) trajectories. Methods This study used a linked-longitudinal sample of G...

Introduction: Within tobacco prevention programming, it is useful to identify youth that are at risk for experimenting with various tobacco products and e-cigarettes. The susceptibility to smoking construct is a simple method to identify never-smoking students that are less committed to remaining smoke-free. However, the predictive validity of thi...

Background: The transition from high school into young adulthood is a critical developmental period with many young people going to college, moving residence, and entering the work force for the first time. The NEXT Generation Health Study (NEXT) is a nationally representative longitudinal study of adolescent health behaviors. Previous NEXT resear...

The incomplete informative cluster size problem is motivated by the National Institute of Child Health and Human Development consecutive pregnancies study, aiming to study the relationship between pregnancy outcomes and parity. These pregnancy outcomes are potentially associated with the number of births over a woman's lifetime, resulting in an inc...

Purpose of the study: The maintenance of cognitive health is an important component of healthy aging. Abnormal cognitive decline can signal the onset of dementing disorders such as Alzheimer's disease (AD). Normal cognitive decline can also adversely affect the health of aging populations. We investigated the association between religious/spiritua...

Background Canadian youth exhibit a number of risky behaviours, some of which are associated with overweight and obesity. The purpose of this study was to examine the prevalence of 15 modifiable risk behaviours in a large sample of Canadian youth, to identify underlying subgroups based on patterns of health behaviours, and to examine the associatio...

Background: Epidemiologic studies examining preconception risk factors on perinatal outcomes are typically restricted to livebirths. By including only non-terminated pregnancies, estimates for the underlying pregnancy cohort may be subject to selection bias. We examined if potential selection bias due to induced termination by maternal race may re...

Introduction Preserving cognitive health is a crucial aspect of healthy ageing. Both abnormal and normal cognitive decline can adversely affect the health of ageing populations. Evidence suggests religious involvement (RI) can preserve cognition in ageing populations. The primary purpose of this review is to examine the evidence regarding the assoc...

Background Youth’s physical activity (PA) may change across developmental periods. Although previous studies have observed a decline in levels of PA during adolescence, few studies have explored trends in PA during the transition from adolescence to young adulthood and what factors may impact the transitional change. The purpose of this study was t...

Objective: The first year after high school is a transitional year, with increased independence from parental supervision, contact with other independent youth, and exposure to new environments, all of which may influence substance use. This article reports longitudinal predictors of change in the prevalence of alcohol use and heavy episodic drink...

Diets of U.S. adolescents and adults do not meet recommendations, increasing risk of chronic disease. This study examined trajectories and predictors of eating behaviors in U.S. youth from age 16–20 years, and evaluated longitudinal associations of eating behaviors with weight outcomes. Data come from the first four waves (years) of the NEXT Genera...

Tests for regression coefficients such as global, local, and partial F-tests are common in applied research. In the framework of multiple imputation, there are several papers addressing tests for regression coefficients. However, for simultaneous hypothesis testing, the existing methods are computationally intensive because they involve calculation...

The aim of this study was to determine reference physical performance values in older aging workers. Cross-sectional physical performance measures were collected for 736 manufacturing workers to assess effects of work and nonwork factors on age-related changes in musculoskeletal function and health. Participants underwent surveys and physical testi...

Model selection is a critical part of analysis of data in applied research. Equally ubiquitous is the notion of incomplete data sets and the challenges presented in analyzing data with missing values. Using principled methods of model selection and handling incomplete data are essential to achieving valid inferences. This dissertation examines mode...

Model selection criteria proposed over the years have become common procedures in applied research. This article examines the true model selection rates of any model selection criterion; with true model meaning the data generating model. The rate at which model selection criteria select the true model is important because the decision of model sele...

Many model selection criteria proposed over the years have become common procedures in applied research. However, these procedures were designed for complete data. Complete data is rare in applied statistics, in particular in medical, public health and health policy settings. Incomplete data, another common problem in applied statistics, introduces...

There are many procedures and settings in SAS® that support the construction of elegant and informative graphs for data analysis. When dealing with complex data, it can be cumbersome to produce graphs that are both informative and consistent in their design. This task can be made easier with some simple macros. This paper introduces a SAS® macro to...