Background: This dissertation addresses the critical public health issue of antiretroviral therapy (ART) adherence among people with HIV (PWH) who inject drugs (PWID) in Kazakhstan, a country experiencing one of the world's fastest-growing HIV epidemics. The research examines factors influencing ART adherence among PWID, with a particular focus on the impact of the COVID-19 pandemic. The central research questions explored are: "What multi-level factors are associated with ART adherence among PWID with HIV in serococordant and serodiscordant relationships?” and "What factors are associated with ART adherence among HIV-positive PWID during the COVID-19 pandemic?” Methods: This study investigated HIV medication adherence among people who inject drugs (PWID) using two complementary methodological approaches. First, qualitative analysis used in-depth interviews with 20 PWID living with HIV and 18 of their intimate partners, analyzing the dyadic data to understand relationship dynamics and shared experiences around medication adherence. Building on these qualitative insights, we then conducted a secondary-data analysis on a cross-sectional survey from October 2020 to August 2022 with 66 HIV-positive PWID and their treatment support partners (n=66). The survey data were analyzed using multilevel generalized linear mixed models with Bayesian estimation to examine factors associated with ≥90% and ≥80% adherence levels. The qualitative findings informed our selection of variables for the quantitative analysis and provided contextual depth to interpret the statistical results. Results: Qualitative results revealed multilevel barriers and facilitators of ART adherence at individual (e.g., substance use), interpersonal (e.g., social support), and structural levels (e.g., stigma, transportation). The manifestation of social support varied between seroconcordant and serodiscordant dyads. Quantitative findings showed low overall ART adherence, with 55.8% of participants achieving ≥80% adherence and only 14.7% reaching the ≥90% threshold. Key factors associated with higher adherence included: having a partner with HIV (AOR=14.94, 95% CI=1.51-420.77) for ≥90% adherence; lower conflict at home during the COVID-19 pandemic (AOR=22.77, 95% CI=1.62-841.84) for ≥90% adherence; and meeting with a professional to discuss alcohol or drug use (AOR=6.78, 95% CI=1.25-117.61) for ≥80% adherence. Factors associated with lower adherence included: poorer mental health (AOR=0.09, 95% CI=0.005, 0.76) for ≥80% adherence and experiencing negative emotional impacts of COVID-19 (AOR=0.18, 95% CI=0.002, 0.98) for ≥80% adherence. Conclusion: This dissertation concludes that relationship factors, social support, partner HIV status, mental health, and the personal impact of public health crises significantly influence ART adherence among PWID. These findings have important implications for public health policy and clinical practice in addressing the HIV epidemic in Kazakhstan and similar contexts, particularly during periods of mass disruption like the COVID-19 pandemic. Future research and interventions may benefit from integrating dyad approaches into ART adherence strategies, considering partner HIV status, prioritizing mental health support, and addressing the personal and household impacts of crises. Such comprehensive approaches could potentially improve health outcomes for PWH and reduce HIV transmission risk among PWID populations.

Background: Chronic diseases have a substantial impact on global health. Plant-based diets, which are abundant in fiber and antioxidants, consistently demonstrate advantages in mitigating cardiovascular risks, controlling diabetes, decreasing cancer rates, and facilitating healthy weight maintenance. Methods: This study evaluated the feasibility, acceptability, and initial efficacy of a 21-day virtual whole-food plant-based (WFPB) dietary intervention, implemented by the non-profit organization Plant Powered Metro New York, among 139 participants. The intervention consisted of weekly educational and mentorship sessions. A mixed-methods study design was used to evaluate the program. Feasibility was assessed based on program attendance. Acceptability was assessed based on self-reported program satisfaction on survey and key informant focus group responses. Pre- and post-program surveys measured changes in perceptions and knowledge of WFPB nutrition, self-efficacy in cooking, adherence to the diet, health-related quality-of-life metrics, and mental health (Patient Health Questionnaire-9 and Generalized Anxiety Disorder-7). Changes in anthropometric measures, including BMI, waist circumference, HbA1c, LDL, total cholesterol, and blood pressure, were measured in a subsample of participants. Pre- to post-program changes were assessed using Wilcoxon signed- rank, McNemar, or McNemar-Bowkers tests. Inductive content analysis was used to assess qualitative data obtained from the focus group participants. Results: Participants attended an average of 73% of the educational sessions, and 89.9% of participants found the program to be satisfactory, describing the experience as “Excellent” or “Good.” Statistically significant improvements were found in self-reported WFPB nutrition knowledge and perceptions regarding challenge, cost, and the ability to adopt and cook a WFPB diet. Participants from the focus group identified program benefits, such as education and improved health, and challenges, such as scheduling issues and misconceptions about WFPB diets. Recommendations include addressing cost misconceptions and providing culturally relevant recipes to enhance program acceptance. There were also statistically significant self- reported improvements in health-related QoL metrics, including pain (other than headaches), headaches, mobility, breathing, skin, gastrointestinal symptoms, hormonal symptoms, sleep, energy, moodiness, mental clarity, and cravings for unhealthy food. There were median decreases of 2.85 points on the PHQ-9 and 1.82 points on the GAD-7, 1.16 kg/m2 in BMI, and 1.65 inches in waist circumference (all p=<0.0001). No significant changes were observed in HbA1c, LDL cholesterol, total cholesterol, or blood pressure levels. Conclusion: The 21-day program was associated with improvements in participants' perceptions of knowledge and self-efficacy regarding WFPB nutrition, self-reported quality-of-life, mental health, and anthropometric measures, including BMI and waist circumference. Future research is needed to assess the long-term results of the program, and to assess the program in patient populations with specific chronic diseases.