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Featured researches published by Jason M. Nagata.


BMC Public Health | 2013

Social determinants of health and seasonal influenza vaccination in adults ≥65 years: a systematic review of qualitative and quantitative data

Jason M. Nagata; Isabel Hernández-Ramos; Anand Sivasankara Kurup; Daniel Albrecht; Claudia Vivas-Torrealba; Carlos Franco-Paredes

BackgroundVaccination against influenza is considered the most important public health intervention to prevent unnecessary hospitalizations and premature deaths related to influenza in the elderly, though there are significant inequities among global influenza vaccine resources, capacities, and policies. The objective of this study was to assess the social determinants of health preventing adults ≥65 years old from accessing and accepting seasonal influenza vaccination.MethodsA systematic search was performed in January 2011 using MEDLINE, ISI – Web of Science, PsycINFO, and CINAHL (1980–2011). Reference lists of articles were also examined. Selection criteria included qualitative and quantitative studies written in English that examined social determinants of and barriers against seasonal influenza vaccination among adults≥65 years. Two authors performed the quality assessment and data extraction. Thematic analysis was the main approach for joint synthesis, using identification and juxtaposition of themes associated with vaccination.ResultsOverall, 58 studies were analyzed. Structural social determinants such as age, gender, marital status, education, ethnicity, socio-economic status, social and cultural values, as well as intermediary determinants including housing-place of residence, behavioral beliefs, social influences, previous vaccine experiences, perceived susceptibility, sources of information, and perceived health status influenced seasonal influenza vaccination. Healthcare system related factors including accessibility, affordability, knowledge and attitudes about vaccination, and physicians’ advice were also important determinants of vaccination.ConclusionsOur results demonstrate that the ability of adults ≥65 years to receive seasonal influenza vaccine is influenced by structural, intermediate, and healthcare-related social determinants which have an impact at the health system, provider, and individual levels.


Aids Care-psychological and Socio-medical Aspects of Aids\/hiv | 2012

Social determinants, lived experiences, and consequences of household food insecurity among persons living with HIV/AIDS on the shore of Lake Victoria, Kenya

Jason M. Nagata; Richard Magerenge; Sera L. Young; Joel O. Oguta; Sheri D. Weiser; Craig R. Cohen

Food insecurity is a considerable challenge in sub-Saharan Africa, disproportionately affecting persons living with HIV/AIDS. This study investigates the lived experience, determinants, and consequences of food insecurity and hunger among individuals living with HIV/AIDS on the shore of Lake Victoria in Suba District, Kenya. Parallel mixed methods included semi-structured interviews and administration of the Household Food Insecurity Access Scale among a systematic sample of 67 persons living with HIV/AIDS (49 of whom were receiving antiretroviral therapy [ART]). All respondents were either severely (79.1%) or moderately (20.9%) food insecure; no respondents were mildly food insecure or food secure. Qualitative data and simple and multiple linear regression models indicated that significant determinants of food insecurity include increased age, a greater number of children, and not being married. A number of themes related to food insecurity and ART emerged, including: (1) an increase in hunger or appetite since initiating ART; (2) exacerbation of ART-related side effects; and (3) non-adherence to ART due to hunger, food insecurity, or agricultural work responsibilities. HIV interventions should address food insecurity and hunger, particularly among at-risk populations, to promote ART adherence and better health outcomes.


Journal of Ethnopharmacology | 2011

Medical pluralism on Mfangano Island: Use of medicinal plants among persons living with HIV/AIDS in Suba District, Kenya

Jason M. Nagata; Alan R. Jew; John M. Kimeu; Charles R. Salmen; Elizabeth A. Bukusi; Craig R. Cohen

ETHNOPHARMACOLOGICAL RELEVANCE Given the increasing coverage of antiretroviral therapy (ART) for HIV/AIDS treatment as well as the high utilization of herbal medicine, many persons living with HIV/AIDS in sub-Saharan Africa are thought to practice medical pluralism, or the adoption of more than one medical system for their care and treatment. Using a cross-sectional study we sought to document and identify the herbal medicines used by persons living with HIV/AIDS on Mfangano Island, Suba District, Nyanza Province, Kenya. MATERIALS AND METHODS We interviewed herbalists and knowledgeable mothers to obtain information regarding medicinal plants, particularly for HIV/AIDS-related symptoms, HIV/AIDS, and chira (an illness concept with similarities to HIV/AIDS regarding sexual transmission and wasting symptoms). Using systematic sampling, 67 persons living with HIV/AIDS (49 of whom were receiving ART) were selected from an Mfangano Island health clinic and participated in semi-structured interviews. RESULTS Interviews with herbalists and mothers identified 40 plant species in 37 genera and 29 families that a person with HIV/AIDS or chira could use for herbal remedies. Overall, 70.1% of persons living with HIV/AIDS had used medicinal plants after HIV diagnosis, most commonly to treat symptoms related to HIV/AIDS. In addition to common vegetables and fruits that can serve medicinal purposes, Azadirachta indica A. Juss. (Meliaceae), Carissa edulis (Forssk.) Vahl (Apocynaceae), and Ximenia americana L. (Olacaceae) were the most frequently cited medicinal plants used by persons living with HIV/AIDS. CONCLUSIONS Collaboration and communication between biomedical clinicians and herbalists should be encouraged given high rates of concomitant ART-herb usage. Pharmacological, toxicological, and ART-herb interaction studies based on the plants identified in this study and their constituent ingredients should be considered.


Clinical Psychology Review | 2017

The enigma of male eating disorders: A critical review and synthesis

Stuart B. Murray; Jason M. Nagata; Scott Griffiths; Jerel P. Calzo; Tiffany A. Brown; Deborah Mitchison; Aaron J. Blashill; Jonathan Mond

Historically, male presentations of eating disorders (EDs) have been perceived as rare and atypical - a perception that has resulted in the systematic underrepresentation of males in ED research. This underrepresentation has profoundly impacted clinical practice with male patients, in which i) stigmatization and treatment non-engagement are more likely, ii) a distinct array of medical complexities are faced, and iii) symptom presentations differ markedly from female presentations. Further, the marginalization of males from ED research has hindered the assessment and clinical management of these presentations. This critical review provides an overview of the history of male EDs and synthesizes current evidence relating to the unique characteristics of male presentations across the diagnostic spectrum of disordered eating. Further, the emerging body of evidence relating to muscularity-oriented eating is synthesized in relation to the existing nosological framework of EDs. The impact of marginalizing male ED patients is discussed, in light of findings from epidemiological studies suggesting that clinicians will be increasingly likely to see males with ED in their practices. It is suggested that changes to current conceptualizations of ED pathology that better accommodation male ED presentations are needed.


Maternal and Child Nutrition | 2012

Social determinants of iron supplementation among women of reproductive age: A systematic review of qualitative data

Jason M. Nagata; Lisa R. Gatti; Frances K. Barg

Iron supplementation for women of reproductive age is a main part of an interdisciplinary strategy recommended for the control and prevention of iron deficiency and the treatment of mild-to-moderate iron-deficiency anaemia. This systematic review reports the findings from a meta-synthesis of qualitative data concerning the experiences and perceptions of iron supplementation among women of reproductive age and health service providers worldwide. Qualitative systematic review methods were used to conduct a search of published literature, define inclusion and exclusion criteria, appraise quality of studies and extract data on the use of iron supplementation among women of reproductive age. Coding, thematic analysis, reciprocal translation and line of argument synthesis were used to synthesize data. Twelve studies spanning 17 countries met inclusion criteria and were included in the analysis. Seven domains emerged from the review: cultural norms and societal values including explanatory models and medical pluralism; political and socio-economic circumstances; education and communication; social organization and social relationships; health care access and supplement supply; food and nutrition availability; and adherence. In addition, 16 sub-domains are highlighted. Connecting review findings to a conceptual framework of social determinants of health highlights salient issues that policy makers must consider when adapting global iron supplementation recommendations to the local context.


The Lancet HIV | 2015

Co-trimoxazole prophylaxis in adults, including pregnant women, with HIV: a systematic review and meta-analysis

Amitabh B. Suthar; Marco Vitoria; Jason M. Nagata; Xavier Anglaret; Dorothy Mbori-Ngacha; Omar Sued; Jonathan E. Kaplan; Meg Doherty

INTRODUCTION Co-trimoxazole prophylaxis is used to reduce morbidity and mortality in people with HIV. We systematically reviewed three topics related to co-trimoxazole prophylaxis to update WHO guidelines: initiation, discontinuation, and dose. METHODS We searched PubMed, Embase, WHO Global Index Medicus, and clinical trial registries in November, 2013, for randomised controlled trials and observational studies including co-trimoxazole prophylaxis and a comparator group. Studies were eligible if they reported death, WHO clinical stage 3 or 4 events, admittance to hospital, severe bacterial infections, tuberculosis, pneumonia, diarrhoea, malaria, or treatment-limiting adverse events. Infant mortality, low birthweight, and placental malaria were additional outcomes for the comparison of co-trimoxazole prophylaxis and intermittent preventive treatment for malaria in pregnant women (IPTp). We compared a dose of 480 mg co-trimoxazole once a day with one of 960 mg co-trimoxazole once a day. We used a 10% margin for non-inferiority and equivalence analyses. We used random-effects models for all meta-analyses. This study is registered with PROSPERO, number CRD42014007163. FINDINGS 19 articles, published from 1995 to 2014 and including 35 328 participants, met the inclusion criteria. Co-trimoxazole prophylaxis reduced rates of death (hazard ratio [HR] 0·40, 95% CI 0·26-0·64) when started at CD4 counts of 350 cells per μL or lower with antiretroviral therapy (ART) worldwide. Co-trimoxazole prophylaxis started at higher than 350 cells per μL without ART reduced rates of death (0·50, 0·30-0·83) and malaria (0·25, 0·10-0·57) in Africa. Co-trimoxazole prophylaxis was non-inferior to IPTp with respect to infant mortality (risk difference [RD] -0·05, 95% CI -0·12 to 0·02), low birthweight (0·00, -0·07 to 0·07), and placental malaria (0·00, -0·10 to 0·10). Co-trimoxazole prophylaxis continuation after ART-induced recovery with CD4 counts higher than 350 cells per μL reduced admittances to hospital (HR 0·42, 95% CI 0·22-0·80), pneumonia (0·73, 0·61-0·88), malaria (0·03, 0·01-0·10), and diarrhoea (0·61, 0·48-0·78) in Africa. A dose of 480 mg co-trimoxazole prophylaxis once a day did not reduce treatment-limiting adverse events compared with 960 mg once a day (RD -0·07, 95% CI -0·52 to 0·39). INTERPRETATION Co-trimoxazole prophylaxis should be given with ART in people with CD4 counts of 350 cells per μL or lower in low-income and middle-income countries. Co-trimoxazole prophylaxis should be provided irrespective of CD4 count in settings with a high burden of infectious diseases. Pregnant women with HIV in Africa should use co-trimoxazole rather than IPTp to prevent malaria complications in infants. Further research is needed to inform dose optimisation and co-trimoxazole use in the context of expanded ART in different epidemiological settings. FUNDING None.


International Journal of Eating Disorders | 2017

Assessment of sex differences in bone deficits among adolescents with anorexia nervosa.

Jason M. Nagata; Neville H. Golden; Rebecka Peebles; Jin Long; Mary B. Leonard; Audrey Chang; Jennifer L. Carlson

OBJECTIVE The objective of this study was to compare sex differences in bone deficits among adolescents with anorexia nervosa (AN) and to identify other correlates of bone health. METHOD Electronic medical records of all patients 9-20 years of age with a DSM-5 diagnosis of AN who were evaluated by the eating disorders program at Stanford with dual-energy X-ray absorptiometry (DXA) between March 1997 and February 2011 were retrospectively reviewed. Whole body bone mineral content Z-scores and bone mineral density (BMD) Z-scores at multiple sites were recorded using the Bone Mineral Density in Childhood Study (BMDCS) reference data. RESULTS A total of 25 males and 253 females with AN were included, with median age 15 years (interquartile range [IQR] 14-17) and median duration of illness 9 months (IQR 5-13). Using linear regression analyses, no significant sex differences in bone deficits were found at the lumbar spine, total hip, femoral neck, or whole body when controlling for age, %mBMI, and duration of illness. Lower %mBMI was significantly associated with bone deficits at all sites in adjusted models. DISCUSSION This is the first study to evaluate sex differences in bone health among adolescents with AN, using novel DSM-5 criteria for AN and robust BMDCS reference data. We find no significant sex differences in bone deficits among adolescents with AN except for a higher proportion of females with femoral neck BMD Z-scores <-1. Degree of malnutrition was correlated with bone deficits at all sites.


Ecology of Food and Nutrition | 2015

Around the Table: Food Insecurity, Socioeconomic Status, and Instrumental Social Support among Women Living in a Rural Kenyan Island Community

Jason M. Nagata; Kathryn J. Fiorella; Charles R. Salmen; Matthew D. Hickey; Brian Mattah; Richard Magerenge; Erin M. Milner; Sheri D. Weiser; Elizabeth A. Bukusi; Craig R. Cohen

The objective of this study was to investigate the relationship among socioeconomic status, social support, and food insecurity in a rural Kenyan island community. A cross-sectional random sample of 111 female heads of households representing 583 household members were surveyed in Mfangano Island, Kenya from August to October 2010 using adaptations of the Household Food Insecurity Access Scale and the Medical Outcomes Study Social Support Survey. In multiple linear regression models, less instrumental social support, defined as concrete direct ways people help others (B = –0.81; 95% confidence interval [CI] –1.45 to –0.17), and decreased ownership scale based on owning material assets (B = –2.93; 95% CI –4.99 to –0.86) were significantly associated with increased food insecurity, controlling for age, education, marital status, and household size. Social support interventions geared at group capacity and resilience may be crucial adjuncts to improve and maintain the long term food security and health of persons living in low-resource regions.


PLOS ONE | 2014

Descriptive Characteristics and Health Outcomes of the Food by Prescription Nutrition Supplementation Program for Adults Living with HIV in Nyanza Province, Kenya

Jason M. Nagata; Craig R. Cohen; Sera L. Young; Catherine Wamuyu; Mary N. Armes; Benard Otieno; Hannah H. Leslie; Madhavi Dandu; Christopher C. Stewart; Elizabeth A. Bukusi; Sheri D. Weiser

Background The clinical effects and potential benefits of nutrition supplementation interventions for persons living with HIV remain largely unreported, despite awareness of the multifaceted relationship between HIV infection and nutrition. We therefore examined descriptive characteristics and nutritional outcomes of the Food by Prescription (FBP) nutrition supplementation program in Nyanza Province, Kenya. Methods Demographic, health, and anthropometric data were gathered from a retrospective cohort of 1,017 non-pregnant adult patients who enrolled into the FBP program at a Family AIDS Care and Education Services (FACES) site in Nyanza Province between July 2009 and July 2011. Our primary outcome was FBP treatment success defined as attainment of BMI>20, and we used Cox proportional hazards to assess socio-demographic and clinical correlates of FBP treatment success. Results Mean body mass index was 16.4 upon enrollment into the FBP program. On average, FBP clients gained 2.01 kg in weight and 0.73 kg/m2 in BMI over follow-up (mean 100 days), with the greatest gains among the most severely undernourished (BMI <16) clients (p<0.001). Only 13.1% of clients attained a BMI>20, though 44.5% achieved a BMI increase ≥0.5. Greater BMI at baseline, younger age, male gender, and not requiring highly active antiretroviral therapy (HAART) were associated with a higher rate of attainment of BMI>20. Conclusion This study reports significant gains in weight and BMI among patients enrolled in the FBP program, though only a minority of patients achieved stated programmatic goals of BMI>20. Future research should include well-designed prospective studies that examine retention, exit reasons, mortality outcomes, and long-term sustainability of nutrition supplementation programs for persons living with HIV.


Journal of Bone and Mineral Research | 2017

Assessment of Sex Differences in Fracture Risk among Patients with Anorexia Nervosa: A Population-Based Cohort Study using The Health Improvement Network.

Jason M. Nagata; Neville H. Golden; Mary B. Leonard; Lawrence Copelovitch; Michelle R. Denburg

Though previous studies have demonstrated an increased fracture risk in females with anorexia nervosa (AN), fracture risk in males is not well characterized. The objective of this study was to examine sex differences in fracture risk and site‐specific fracture incidence in AN. We performed a population‐based retrospective cohort study using The Health Improvement Network (THIN; a large database of anonymized electronic medical records collected at primary care clinics throughout the United Kingdom). The median calendar year for the start of the observation period was 2004–2005. We identified 9239 females and 556 males <60 years of age with AN, and 97,889 randomly selected sex‐, age‐, and practice‐matched participants without eating disorders (92,329 females and 5560 males). Multivariable Cox regression was used to estimate the hazard ratio (HR) for incident fracture. Median age at start of observation was 29.8 years in females and 30.2 years in males. The HR for fracture associated with AN differed by sex and age (interaction p = 0.002). Females with AN had an increased fracture risk at all ages (HR, 1.59; 95% confidence interval [CI], 1.45 to 1.75). AN was associated with a higher risk of fracture among males >40 years of age (HR, 2.54; 95% CI, 1.32 to 4.90; p = 0.005) but not among males ≤40 years. Females with AN had a higher risk of fracture at nearly all anatomic sites. The greatest excess fracture risk was noted at the hip/femur (HR, 5.59; 95% CI, 3.44 to 9.09) and pelvis (HR, 4.54; 95% CI, 2.42 to 8.50) in females and at the vertebrae (HR, 7.25; 95% CI, 1.21 to 43.45) for males with AN. AN was associated with higher incident fracture risk in females across all age groups and in males >40 years old. Sites of highest fracture risk include the hip/femur and pelvis in females and vertebrae in males with AN.

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Craig R. Cohen

University of California

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Elizabeth A. Bukusi

Kenya Medical Research Institute

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Rebecka Peebles

Children's Hospital of Philadelphia

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