The study of social relationships and health has been one of the main issues of sociology. A growing number of literatures have demonstrated the association between social relationships and health. The findings generally showed that people who were socially integrated, received social support, and participated in non-working social organizations tended to be physically and psychologically healthier than those who were not; however, less is known about the process and structure of social relationships in the sociological investigation of health. Studies were often limited in that they did not thoroughly investigate the determinants of social relationships in relation to health. In the present study, I suggest that social contexts will enlarge our understanding of the association between social relationships and health. I employ the term social contexts to refer to distinctive dimensions of social structures and institutions in which individuals are embedded. If social contexts are probable determinants of social relationships, social contexts appear to have an effect on health status as well as social relationships. Despite this proposition, few studies have examined the associations among social contexts, social relationships, and health in an integrated analytical framework. The main objective of this project is, thus, to examine the association among the distinctive layers of social contexts--family, workplace, and neighborhoods--, social relationships and health. Using the first and second wave of the Americans’ Changing Lives panel data, I test four main research questions. First, are social contexts associated with health outcomes? Second, are social contexts predictive of a variety of social relationships? Third, do social relationships account for the association between social contexts and health outcomes? Finally, do social contexts moderate the association between social relationships and health outcomes? Neighborhood contexts are associated with depression and self-rated health of the first wave net of controls. Neighborhood contexts are predictive of a variety of social relationships. Social relationships account for the associations between the percentage of households receiving public assistance, foreign-born residents, and female-headed households, and depression of the first wave. Some of the associations between social relationships and health outcomes are moderated by neighborhood contexts, and the moderating effects vary by the types of social relationships. Workplace contexts are generally associated with depression, but not largely associated with self-rated health. Workplace contexts are predictive of a variety of social relationships. Social relationships only moderately account for the effects of job decision latitude, physical demands, and psychological demands on depression of the second wave, and psychological demands on self-rated health of the first wave. The associations between social relationships and health outcomes are moderated by workplace contexts in some cases, and the moderating effects vary by the types of social relationships. Family contexts are generally associated with depression and self-rated health in both cross-sectional and longitudinal settings. Family contexts are predictive of a variety of social relationships. Social relationships mediate some of the associations between family context variables and health; the effect of family context variables on self-rated health of the second wave are explained by social relationships in models of having children, parental chronic stress, mother support, child support, and spouse support. Some of the associations between social relationships and health status are moderated by family contexts, and the moderating effects vary by the types of social relationships. / text

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

The objective of this study was to examine the effects of a medium chain triglyceride oil mixture (MCTo), designed to increase energy expenditure and improve lipid profiles containing medium chain triglycerides, phytosterols and n-3 fatty acids in the form of flaxseed oil, versus the antioxidant alpha-lipoic acid (ALA). Forty-eight hamsters were fed (i) hypercholesterol emic (HC) control, (ii) HC MCTo, (iii) HC ALA, (iv) HC MCTo/ALA diets for 4 weeks. No effects on food intake, body weight, total body water, lean body mass, fat mass, and tissue thiobarbituric acid-reactive substances (TBARS) were observed. ALA alone had no effect on total cholesterol (TC); however, MCTo feeding increased TC with (p < 0.03) and without (p < 0.003) ALA when compared to control. ALA increased HDL levels compared to control (p 0.04) and MCTo/ALA (p < 0.007) groups. MCTo, with (p < 0.0001) or without (p < 0.006) ALA, increased non-HDL cholesterol levels versus control. The non-HDL:HDL ratio was decreased by ALA compared to MCTo (45%) and MCTo/ALA (68%) (p < 0.0001), a similar trend was seen when compared to the HC control (22%) group (p < 0.14). Triglyceride levels were not altered by any of the dietary treatments. Liver and heart tissue reduced glutathione (GSH) was increased (p < 0.05) by all three treatments when compared to control. Both tissues showed an increase (p < 0.05) in oxidized glutathione (GSSG) when fed ALA compared to all other treatments. Hamsters fed ALA had a lower (p < 0.05) GSH/GSSG ratio compared to all treatment groups. In conclusion, MCTo feeding does not elicit beneficial effects on circulating plasma lipids and measures of body composition. In addition, our results do not clearly support an improvement in oxidative status through supplementation of ALA. However, our results do support the existence of beneficial effects of ALA on circulating lipoprotein content in the hamster.

Thesis (MSc Nutrition Science)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: Probiotics (live microbes) and prebiotics (non-digestible food-ingredients) are rapidly gaining interest worldwide as supplements and functional food ingredients but little South African information in this regard is available. Furthermore, the availability of South African produced probiotic concentrates for commercial use is also very limited. The aims of this study therefore were to complete a market and product assessment of probiotic and prebiotic containing products in South Africa and to evaluate probiotic strains for commercial use in South Africa. For the purposes of market and product assessment probiotic and/or prebiotic containing products manufactured in South Africa were identified. The scientific and legal correctness of health and content claims made on the labels of the products were assessed. An exploratory survey was conducted to determine the awareness of South African consumers of probiotics and prebiotics. For the evaluation of probiotic strains for potential commercial use in South Africa, a panel of twelve lactic acid bacteria (LAB) were screened for inhibitory activity against two porcine pathogens and indicator strains from the LMG-panel isolated from the faeces of patients diagnosed with AIDS. The five LAB with the best inhibitory activity were tested for growth in soymilk-base and for the effect of lyophilization on the inhibitory activity thereof. The effect of prebiotics on the growth and inhibitory activity of the strains was tested in vitro. A range of products containing probiotics and prebiotics available on the South African market was identified. Irregulatories concerning health claims on the labels were found, but content claims seemed to be less of a problem. The results also indicate that the proposed South African regulations for the labelling of probiotic and prebiotic containing products need to be revised to include the probiotic and prebiotic related health claims for which sufficient scientific evidence is available. The probiotic strains with potential for commercial use in South Africa that were identified, include Lactobacillus plantarum 423, Lactobacillus casei LHS, Lactobacillus salivarius 241, Lactobacillus curvatus DF38 and Pediococcus pentosaceus 34. These strains were grown successfully in soymilkbase and lyophilization did not have a negative effective on the inhibitory activity thereof. The growth and inhibitory activity of the five LAB were promoted when combined with 1% (w/v) Raftilose® Synergyl . It is concluded that although a variety of probiotic and prebiotic containing products are available on the South African market, the scientific and legislative correctness of especially health related claims is not satisfactory and that South African consumer awareness of these products is low. It is also concluded that a combination of at least three of the five identified LAB and 1% Raftilose® Synergy can be used by South African manufacturers for the production of probiotic and prebiotic containing supplements. / AFRIKAANSE OPSOMMING: Die belangstelling in probiotika (lewendige mikrobe) en prebiotika (onverteerbare voedselbestanddele) as supplemente en funksionele voedselbestanddele is besig om wêreldwyd toe te neem, alhoewel weinig Suid-Arikaanse inligting in hierdie verband beskikbaar is. Die beskikbaarheid van Suid-Afrikaans geproduseerde probiotika konsentrate vir kommersïele gebruik is ook baie beperk. Die doelwitte van hierdie studie was dus om 'n mark- en produkevaluering van probiotika- en prebiotika-bevattende produkte in Suid-Afrika uit te voer en om probiotiese stamme te evalueer vir uiteindelike kommersiële gebruik in Suid-Afrika. Vir die doel van die mark- en produkevaluering is probiotika- en prebiotika-bevattende produkte wat in Suid-Afrika vervaardig word geïdentifiseer. Die wetenskaplike en wetlike korrektheid van die gesondheids- en inhoudsaansprake op die etikette van die produkte is evalueer. 'n Markopname is uitgevoer om die bewustheid van Suid-Afrikaanse verbruikers van probiotika en prebiotika vas te stel. Vir die evaluering van probiotiese stamme vir potensïele kommersiële gebruik in Suid-Afrika is 'n paneel van twaalf melksuurbakteriëe getoets vir inhibitoriese aktiwiteit teen twee patogene geïsoleer uit varke asook teen indikator stamme van die LMG-paneel. Die vyf melksuurbakteriëe met die beste inhibitoriese aktiwiteit is getoets vir groei in sojamelk-basis en ook vir die effek van vriesdroging op die groei en inhibitoriese aktiwiteit van die stamme daarvan. Die effek van prebiotika op die groei en inhibitoriese aktiwiteit van die stamme is in vitro getoets. 'n Reeks van probiotika- en prebiotika-bevattende produkte wat beskikbaar is op die Suid-Afrikaanse mark, is geidentifiseer. Ongeruimdhede met die gesondheidsaansprake op die etikette is gevind, maar inhoudsaansprake was minder problematies. Die resultate dui ook daarop dat die voorgestelde Suid- Afrikaanse regulasies vir die etikettering van probiotika- en prebiotika-bevattende produkte hersien moet word om al die probiotika- en prebiotika-verwante gesondheidsaansprake waarvoor voldoende wetenskaplike bewyse beskikbaar is in te sluit. Die probiotiese stamme met potensiaal vir kommersiële gebruik in Suid-Afrika sluit die volgende in: Lactobacillus plantarum 423, Lactobacillus casei LHS, Lactobacillus salivarius 241, Lactobacillus curvatus DF 38 en Pediococcus pentosaceus 34. Hierdie stamme is suksesvol gekweek in sojamelk-basis en vriesdroging het nie' n negatiewe effek op die groei en inhibitoriese aktiwiteit daarvan gehad me. Die kombinasie van die vyf melksuurbakteriëe met 1% Raftilose® Synergy het die groei en inhibitoriese aktiwiteit daarvan bevorder. Die gevolgtrekking wat gemaak word is dat alhoewel 'n varrasie van probiotika- en prebiotikabevattende produkte beskikbaar is op die Suid-Afrikaanse mark, die wetenskaplike en wetlike korrektheid van spesifiek die gesondheids-verwante aansprake op die etikette daarvan nie bevredigend is nie en dat die bewustheid van die Suid-Afrikaanse verbruikers van hierdie produkte laag is. Die gevolgtrekking kan ook gemaak word dat 'n kombinasie van ten minste drie van die vyf geïdentifiseerde melksuurbakteriëe en 1% Raftilose® Synergy deur Suid-Afrikaanse vervaardigers gebruik kan word vir die vervaardiging van produkte wat probiotika en prebiotika bevat.

M.Sc.

Exposure to volatile organic compounds (VOCs) has critical health implications for developing fetuses and subsequently for infants and young children. Research has suggested that this ambient air pollutant can be found indoors in quantities that may be hazardous to human health. In low-income neighborhoods in New York City such as northern Manhattan and the South Bronx, where there are disproportionately high rates of asthma and asthma-related hospitalizations, high rates of indoor exposure to VOCs persist. Simultaneously, as mobile devices expand, applications on mobile devices may be used to educate parents of children who reside in these geographic regions about indoor VOC emission sources and subsequently how to reduce exposure.Therefore, this study sought to assess the role of mobile device applications in reducing household VOCs by assessing the feasibility of existing health applications on both Apple and Android OS mobile devices without the use of a household air monitoring unit. An online survey assessed awareness of VOCs and identified knowledge of both emission sources and reduction methods of household VOCs among a sample of (N = 57) parents/guardians residing in the Northern Manhattan and Southern Bronx regions with children under the age of 5. A series of focus groups were conducted among a subset of participants to assess the adaptability of a mobile application prototype that specifically targets the reduction of VOCs. Lastly, a preliminary mobile device application mockup was created with potential features. The key findings of this study included the following: (a) the author identified no existing mobile device applications that could be utilized as a method for VOC reduction without the use of a physical in-home air monitor; (b) while parents had some baseline awareness of VOCs, there were gaps within their knowledge of VOCs, particularly with emission sources; (c) the feasibility of this proposed application as a potential source of intervention for indoor VOC mitigation was apparent through parent willingness to explore its possible use, while providing ample recommendations for optimal mobile device application design; and (d) the exploratory mockup of the proposed mobile device application was generated with suggested features.

No description available.

An energy transition can be defined as the adoption of a new primary energy system. As such, it is a structural change that implies a broad shift in technologies and behaviors in order to replace one source of energy with another. Energy transitions motivated by economic, climate, and/or health goals are taking place everywhere in the world. Air pollution, a consequence of fossil fuel-based and solid fuel-based energy use among other sources, is the largest environmental health risk accounting for 6.4 million premature deaths annually. Given the health implications of our energy systems and the social drivers of energy use, access, and burden, energy transitions have the potential to impact health outcomes and associated disparities in a context-dependent manner. The research presented in this dissertation has two objectives: 1) to evaluate the distribution of benefits from energy transitions in the United States (US) and in Ghana; 2) to identify and characterize health outcomes that are relevant to these transitions but are currently understudied. Chapters 2 and 3 are anchored in the US energy policy context. Chapter 2 focuses on the transition away from coal as the primary source of energy in the US and its implications for particulate matter pollution and preterm births. Leveraging a novel dispersion model, I assessed the association between coal PM2.5 and preterm birth rates along with effect modification by race/ethnicity. We observed a positive non-linear relationship between coal PM2.5 and preterm birth rate, which plateaued at higher levels of pollution. The findings of this study suggest that the transition away from coal may have reduced preterm birth rates in the US, but that the association was stronger among non-Hispanic White women compared to non-Hispanic Black women. In Chapter 3, I use a mixed-methods framework to evaluate the first pilot of gas-to-electric stove transition in low-income housing in the US. Through a collaboration with a community-based environmental justice group in New York City, we monitored indoor air quality in participants homes pre- and post-intervention, conducted controlled cooking tests, and carried out focus groups to characterize their experience. Post-intervention, daily NO2 concentrations were 46.3% (95% CI: -67.8%, -10.3%) lower in the intervention arm compared to the control arm. Participants were unanimously pleased with the transition, which had simultaneously improved their cooking experience and partially addressed energy insecurity concerns that plagued their building. Chapters 4 and 5 contribute to the characterization of the health implications associated with Ghana’s commitment to increase access to liquified petroleum gas (LPG) nationally. In Chapter 4, we aimed to describe the country-level incidence of severe cooking-related burns by fuel type in use and to identify effect modifiers. We conducted a nationally representative (n = 7,389) household energy use survey in all 16 regions of Ghana. The incidence rate (95% CI) of cooking-related burns per 1000 person-years among working age females was 8.3 (7.2; 12.0) per 1000 person-years, which was 8 times higher than that of working age males. Among adults, the odds of experiencing a cooking-related burn were doubled among solid fuel users compared to primary LPG users. In Chapter 5, we aimed to understand the effect of an LPG intervention on personal exposure to household air pollution in a peri-urban setting of Ghana and to characterize the distribution of benefits between male and female household members quantitatively and qualitatively. The difference-in-differences results suggested a reduction in exposure to carbon monoxide due to the intervention (-14.2%, 95% CI: -44.1%, 31.6%), which might have benefited male and female participants to the same extent. Importantly, focus group discussions suggested that the ability that LPG affords to cook “on demand” could negatively impact intra-household dynamics and expectations in a way that has not been previously documented. Taken together, our findings from two distinct socioeconomic contexts, highlight the non-uniform distribution of benefits from energy transitions, especially when benefits that are not mediated by air pollution are considered. These results contribute to the understanding that social drivers of inequities should be integrated in the design of energy policies and interventions aimed at generating equitable outcomes. Future directions include a detailed characterization of the context-dependent relative contributions of indoor and outdoor air pollution sources as well as a more systematic integration of quantitative and qualitative methods in policy evaluation.

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.

Reducing health disparities and achieving health equity in maternal and infant health is a critical concern for social work and public health stakeholders more generally. This three-paper dissertation is dedicated to exploring program or policy modifiable social determinants of maternal and infant health with a particular focus on vulnerable populations. Paper one explores the influence of household members on women’s sexual and reproductive behaviors. Paper two studies the impact of smoke-free regulations on birth outcomes in Latin America. Lastly, paper three looks at the effects of police use of force, and racialized police use of force, on maternal and infant health. The findings of these papers provide important information to inform programs and policies aimed at improving reproductive health and well-being in the U.S. and Latin America.