Thesis (M.A. (Communication Studies)) -- University of Limpopo, 2020 / Hubbly Bubbly smoking is a visibly growing trend among young people globally. However, health promotion about the risks that result from hubbly bubbly smoking has not been vigilant so far. The study attempts to determine youth’s knowledge and perceptions towards the health risks incurred from smoking the HB. The study triangulates three theories namely: The Extended Parallel Process Model, Peer Cluster Theory and Hofstede’s Cultural Theory using a mixed method approach among University of Limpopo students. A sample of 350 students was used, made up of n=175 HB users and n=175 non-users. In the quantitive part of the study, a 2 x 2 between and within respondents design was followed. Most HB users 74% (129) and non-users 80% (140) identified lung cancer as the health risk of HB smoking. Participants perceived HB smoking health risks as exaggerated, and that HB is less addictive and less harmful. The majority of participants (75%) had not heard or seen any health communication awareness campaigns about HB risks. Focus group interviews revealed that participants perceived HB as less harmful, less expensive with no visible health warning and not addictive to every user. Findings suggest that there is inadequacy in terms of knowledge as well as negative perceptions towards HB and its health risks. There should be more health communication campaigns that will engage the youth and the public, and the media should speak more about HB and its health risks. The study contributes to the body of knowledge about health communication campaigns about existing problems. / National Research Foundation (NRF)

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Agro-terrorism has become a major concern since the September 11, 2001, terrorist attacks due to characteristics that create unique problems for managing the threat of an agro-terrorist attack. The costs of trucking delays alone were in the tens of millions of dollars. Over the last few years, the government has spent billions of dollars on biological surveillance and record keeping in preventing potential attacks. Several public and private initiatives are currently in use. Examples include 1) the bio-terrorism regulation of 2004 on maintenance of records; 2) establishment of food protection centers for research and teaching excellence; and 3) investments in emerging technology, such as radio frequency monitoring (RFEM) technology, with the potential to track shipments and provide real-time data that can be used to prevent agro-terrorism risks along food supply chains. This thesis addresses the costs and risk premiums associated with alternative tracking strategies, where and when along the milk supply chain these strategies will reduce the most risks, and what policy implications are associated with the most costeffective tracking strategy. To accomplish these objectives, stochastic optimization is used to determine the costs and risk premiums of alternative tracking strategies. Next, the realoptions method along with a portfolio of options, also referred to as the "tomato garden" framework, is used to determine where and when alternative intervention strategies should be implemented to reduce the most risks. Finally, policy implications are derived on the cost-risk tradeoffs, probability of attacks, and containment efforts if there is an attack by using game theory to determine the incentives needed to motivate participants in the milk supply chain to invest in security measures.

In consideration of the demographic trends of our population, it is necessary to deal with the old age problems and problems of geriatric patients. The controversial topic of restraints, especially sensitive in association with old frail people, is closely related. The issue of restraints is defined by law. However, the ethical aspects of their application should also be considered. The theoretical part of this thesis deals with the topic of old age and serious problems of this period of life, including mental disorders. It introduces the field of geriatrics and geriatric patients. In further chapters, this thesis discusses the restraints and ethical issues related to their use. By using qualitative research methods, the empirical part of this thesis surveys the attitudes of healthcare professionals towards this issue. It discusses specific restraints and the reasons for which they are used. The results show that the most important value of healthcare professionals is health and the most respected ethical principle is the principle of beneficence. Key Words: old age, geriatric patient, health risk, restraints, ethical principle

Cardiovascular diseases (CVD) are responsible for more deaths than any other disease, continue to threaten the quality of life for many, and is a major burden to the health care system. The Framingham Heart Study (FHS) identified the major CVD risk factors that became essential to effective CVD screening strategies and the Framingham Risk Score (FRS), is used to assess CVD risk. Based on the concepts of the health behavior model and CVD as a cardiometabolic disorder, multivariate logistic regression analysis was used to evaluate the association between fasting blood glucose (FBG) levels and a CHD event, and to determine the value of FBG replacing a diagnosis of diabetes (DM2) in the FRS. The data set consisted of the 2,677 subjects of the FHS III cohort. In the univariate analysis, both DM2 and FBG were statistically significant (both p =.000), but the association was stronger for DM2, b = 2.138, OR = 8.483 (95% CI: 4.229, 17.105) than for FBG, b = .015, p = .000, OR=1.015 (95% CI: 1.009, 1.022). When adjusted for age, blood pressure, cholesterol, and smoking status, only DM2 remained statistically significant, OR = 2.295, p = .041, (95% CI: 1.035, 5.087) in the model. The FBG version of the FRS did not provide any improvement in performance, as it was marginally inferior to the DM2 version. Furthermore, the interactions between FBG and the metabolic risk factors were not statistically significant for this given data set. The results imply that a diagnosis of diabetes remains the factor of choice for inclusion in the FRS model for predicting the 10-year risk of CHD and replacing it with FBG provides little to no practical benefit. These findings support the use of CVD risk factor reduction and the use of effective screening tools in CVD prevention and promotion heart health.

Secular trends in breast cancer incidence in younger women suggest environmental factors, like exposure to environmental chemicals, may play a role in rising incidence. One of the strongest risk factors for developing breast cancer, next to family history, is high mammographic breast density, which is defined as the proportion of fibroglandular breast tissue relative to fat as seen on a mammogram. Phthalates, a ubiquitous endocrine disrupting chemical, have the potential to interfere with endogenous hormones like estrogen and androgens. There is growing evidence from animal and epidemiologic studies indicating distinct periods of heightened susceptibility to endocrine disrupting chemicals throughout the life course, particularly during critical windows of breast development. Exposure to hormonally active environmental chemicals like phthalates may be a modifiable risk factor for breast cancer, therefore reducing or eliminating exposure could have substantial public health benefits. The overarching goal of this dissertation was to assess the relationship between exposure to phthalates during two critical windows of susceptibility, the prenatal and pregnancy periods, and its effect on breast tissue composition in adolescence and adulthood. First, a comprehensive review of epidemiologic studies summarized the body of evidence for the association between phthalate exposure and intermediate markers known to be in the causal pathway of breast cancer risk (age at breast development, menarche, and breast tissue composition). This systematic review of the literature aimed to identify potential patterns of evidence by outcome and timing of exposure. Evidence from this review suggested that phthalate exposure during the prenatal and childhood periods may play a role in altering menarche. Findings for phthalate exposure and age at breast development were inconclusive. There was a considerable lack of epidemiologic data on phthalate exposure and breast tissue composition throughout the life course. Based on one study, there is a potential association between phthalate exposure during pre-puberty and altered breast tissue density in adolescent girls. No study assessed the relationship between phthalate exposure during the prenatal or pregnancy period and subsequent breast tissue composition. Second, an examination for the association between prenatal phthalate exposure and breast tissue composition measured in adolescence (Chapter 3) and the association between phthalate exposure during pregnancy and breast tissue composition measured during or after the postpartum transient period (Chapter 4) aimed to address this major gap identified from the comprehensive review. The empirical chapters of this dissertation used data from an ongoing longitudinal birth cohort study of mothers and their children conducted by the New York City Columbia Center for Children's Environmental Health and the Breast Cancer and the Environment Research Project (CCCEH-BCERP). The CCCEH-BCERP study cohort has prospective data on nine phthalate metabolite concentrations measured during the third trimester of pregnancy and breast tissue composition measured in a subsample of mother-daughter dyads. Notably, we used novel non-invasive methods (optical breast spectroscopy) in this younger cohort of mothers and daughters to objectively measure specific components of the bulk breast composition before mammography screening age. There was significant evidence of altered breast tissue composition in both mothers and daughters. For daughters (n=127, mean age 15.2 ± 1.9 years), prenatal exposures to select low molecular weight (LMW) and high molecular weight (HMW) phthalate metabolites altered overall breast density in opposing directions, which appears to be driven by significant altered percent breast water. There was a significant association between higher prenatal levels of a LMW phthalate metabolite (monobutyl phthalate) and lower levels of overall breast density (adjusted β = -0.32; 95% CI: -0.51, -0.13) and significant association between sum of di(2-ethylhexyl) phthalate (∑DEHP), a HMW phthalate metabolite, and higher levels of overall breast density in girls (adjusted β = 0.20; 95% CI: 0.05, 0.34). For mothers (n=133, mean age 41 ± 5.3 years at follow-up), there was a significant association between two LMW phthalate metabolites and lower levels of percent breast collagen. Additionally, there was a significant inverse relationship between levels of mono-(3-carboxypropyl), a HMW phthalate metabolite, and percent total hemoglobin of the breast (adjusted β =-0.03; 95% CI: -0.06, 0.00, p=0.05). Overall, this dissertation increased our understanding of the impact that exposure to phthalates during critical windows of susceptibility may have on specific components of the breast. Reducing exposure to both HMW and LMW phthalates may have an impact in reducing breast cancer risk, particularly for girls prenatally exposed, as there was stronger evidence of higher overall breast density and percent water from exposure to select HMW phthalates. Future prospective studies should confirm these results as findings might provide an opportunity for modifying potential breast cancer risk.

Based on the concentrations of ten heavy metals (As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Zn, Fe) in 144 road dust samples collected from 36 sites across 4 seasons from 2016 to 2017 in Beijing, this study systematically analyzed the levels and main sources of health risks in terms of their temporal and spatial variations. A combination of receptor models (positive matrix factorization and multilinear engine-2), human health risk assessment models, and Monte Carlo simulations were used to apportion the seasonal variation of the health risks associated with these heavy metals. While non-carcinogenic risks were generally acceptable, Cr and Ni induced cautionary carcinogenic risks (CR) to children (confidence levels was approximately 80% and 95%, respectively). Additionally, fuel combustion posed cautionary CR to children in all seasons, while the level of CR from other sources varied, depending on the seasons. Heavy metal concentrations were the most influential variables for uncertainties, followed by ingestion rate and skin adherence factor. The values and spatial patterns of health risks were influenced by the spatial pattern of risks from each source.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23182号 / 工博第4826号 / 新制||工||1754(附属図書館) / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 米田 稔, 教授 高野 裕久, 教授 松井 康人 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

Environmental exposure levels are often sufficiently disparate between populations such that there is little or no overlap, complicating our ability to ascertain the full dose-response curve and as such create informed regulatory policy.I reviewed the literature on methods available to address non- and partially-overlapping exposure distributions, drawing from both epidemiology as well as other relevant disciplines to describe the universe of proposed solutions. I also used the case study of maternal PCB-153 exposure and birthweight, utilizing real-world and simulated data to explore our ability to ascertain “true” dose-response curves from observational data given the limited cohort-specific exposure ranges. I investigated the importance of controlled and uncontrolled confounding as well as the impact of sample size on our ability to ascertain a “true” underlying dose-response curve. Pooling and meta-analysis were useful to increase the heterogeneity of exposure distributions despite imperfect confounding control and heterogenous confounding structures across cohorts. The analyses also serve as continued evidence of the challenges of making population-wide inferences from study samples with restricted exposure ranges as well as the danger of pooling multisite data without sufficiently accounting for heterogeneity in both exposure level and distribution of confounders. These results highlight the limitations of using both individual studies and systematic reviews of environmental chemicals, and emphasize the need for pooling and meta-analysis to widen exposure distributions that in turn permit us to accurately capture the negative effects of these environmental chemicals.

The conventional battery for genotoxicity testing is not well-suited to assessing the large number of chemicals needing evaluation. Traditional in vitro tests lack throughput capacity, provide little mechanistic information, and have poor specificity in predicting in vivo genotoxicity. The Health Canada GeneTox21 research program is developing a multi-endpoint platform for modernized in vitro genotoxicity assessment. The GeneTox21 assays include the TGx-DDI transcriptomic biomarker (i.e., 64-gene expression signature to identify DNA damage-inducing (DDI) substances), the MicroFlow® assay (i.e., a flow cytometry-based micronucleus (MN) test), and the MultiFlow® assay (i.e., a multiplexed flow cytometry-based reporter assay that yields mechanism-of-action (MoA) information). As part of GeneTox21 development, the objective of this study was to investigate the utility of the TGx-DDI transcriptomic biomarker, multiplexed with the MicroFlow® and MultiFlow® assays, as an integrated testing strategy for screening data-poor substances prioritized by Health Canada’s New Substances Assessment and Control Bureau. Human lymphoblastoid TK6 cells were exposed to 3 control and 10 data-poor substances, using a 6-point concentration range. Cells were exposed for 4 hours with or without exogenous metabolic activation. Gene expression profiling was conducted using the targeted TempO-SeqTM assay, and the TGx-DDI classifier was applied to the dataset. Classifications were compared with those based on the MicroFlow® and MultiFlow® assays. Benchmark Concentration (BMC) modeling was used for potency ranking. The results of the integrated hazard calls indicate that five data-poor compounds are genotoxic in vitro, causing DNA damage via a clastogenic MoA, and one is positive via a pan-genotoxic MoA. Two compounds are likely irrelevant positives in the MN test; two are considered possibly genotoxic causing DNA damage via an ambiguous MoA. From quantitative analyses of concentration-response data, we observed nearly identical potency rankings for each assay with two main potency groups being observed. This ranking was maintained when all endpoint BMCs were converted into a single score using the Toxicological Prioritization (ToxPi) approach. Overall, this study contributes to the establishment of a modernized approach for effective genotoxicity assessment and chemical prioritization for further regulatory scrutiny. We conclude that integration of the TGx-DDI biomarker with other GeneTox21 assays is an effective NAM-based strategy for genotoxicity assessment of data-poor compounds.