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Open Access Publications from the University of California

Scholarly Works (10 results)

  • Article
  • Peer Reviewed
UC San Diego Previously Published Works (2017)
BACKGROUND:Calls for evidence-informed public health policy, with implicit promises of greater program effectiveness, have intensified recently. The methods to produce such policies are not self-evident, requiring a conciliation of values and norms between policy-makers and evidence producers. In particular, the translation of uncertainty from empirical research findings, particularly issues of statistical variability and generalizability, is a persistent challenge because of the incremental nature of research and the iterative cycle of advancing knowledge and implementation. This paper aims to assess how the concept of uncertainty is considered and acknowledged in World Health Organization (WHO) policy recommendations and guidelines. METHODS:We selected four WHO policy statements published between 2008-2013 regarding maternal and child nutrient supplementation, infant feeding, heat action plans, and malaria control to represent topics with a spectrum of available evidence bases. Each of these four statements was analyzed using a novel framework to assess the treatment of statistical variability and generalizability. RESULTS:WHO currently provides substantial guidance on addressing statistical variability through GRADE (Grading of Recommendations Assessment, Development, and Evaluation) ratings for precision and consistency in their guideline documents. Accordingly, our analysis showed that policy-informing questions were addressed by systematic reviews and representations of statistical variability (eg, with numeric confidence intervals). In contrast, the presentation of contextual or "background" evidence regarding etiology or disease burden showed little consideration for this variability. Moreover, generalizability or "indirectness" was uniformly neglected, with little explicit consideration of study settings or subgroups. CONCLUSION:In this paper, we found that non-uniform treatment of statistical variability and generalizability factors that may contribute to uncertainty regarding recommendations were neglected, including the state of evidence informing background questions (prevalence, mechanisms, or burden or distributions of health problems) and little assessment of generalizability, alternate interventions, and additional outcomes not captured by systematic review. These other factors often form a basis for providing policy recommendations, particularly in the absence of a strong evidence base for intervention effects. Consequently, they should also be subject to stringent and systematic evaluation criteria. We suggest that more effort is needed to systematically acknowledge (1) when evidence is missing, conflicting, or equivocal, (2) what normative considerations were also employed, and (3) how additional evidence may be accrued.
    Cover page: Lost in Translation: Piloting a Novel Framework to Assess the Challenges in Translating Scientific Uncertainty From Empirical Findings to WHO Policy Statements
    • Article
    • Peer Reviewed
    UC Berkeley Previously Published Works (2020)
    [This corrects the article DOI: 10.1097/EE9.0000000000000026.].
      Cover page: Erratum: Maternal Peripartum Urinary Pyrethroid Metabolites are Associated with Thinner Children at 3.5 Years in the VHEMBE Birth Cohort (Limpopo, South Africa): Erratum.
      • Article
      • Peer Reviewed
      UC Irvine Previously Published Works (2017)

      Background

      Racial/ethnic disparities in preterm birth (PTB) are well documented in the epidemiological literature, but little is known about the relative contribution of different social and environmental determinants of such disparities in birth outcome. Furthermore, increased focus has recently turned toward modifiable aspects of the environment, including physical characteristics, such as neighborhood air pollution, to reduce disparities in birth outcomes.

      Objectives

      To apply decomposition methods to understand disparities in preterm birth (PTB) prevalence between births of non-Hispanic black individuals and births of non-Hispanic white individuals in California, according to individual demographics, neighborhood socioeconomic environment, and neighborhood air pollution.

      Methods

      We used all live singleton births in California spanning 2005 to 2010 and estimated PTBs and other adverse birth outcomes for infants borne by non-Hispanic black mothers and white mothers. To compare individual-level, neighborhood-level, and air pollution [Particulate Matter, 2.5 micrometers or less (PM2.5) and nitrogen dioxide (NO2)] predictors, we conducted a nonlinear extension of the Blinder-Oaxaca method to decompose racial/ethnic disparities in PTB.

      Results

      The predicted differences in probability of PTB between black and white infants was 0.056 (95% CI: 0.054, 0.058). All included predictors explained 37.8% of the black-white disparity. Overall, individual (17.5% for PTB) and neighborhood-level variables (16.1% for PTB) explained a greater proportion of the black-white difference in birth outcomes than air pollution (5.7% for PTB).

      Conclusions

      Our results suggest that, although the role of individual and neighborhood factors remains prevailing in explaining black-white differences in birth outcomes, the individual contribution of PM2.5 is comparable in magnitude to any single individual- or neighborhood-level factor. https://doi.org/10.1289/EHP490.
        Cover page: Decomposition Analysis of Black-White Disparities in Birth Outcomes: The Relative Contribution of Air Pollution and Social Factors in California.Creative Commons 'BY' version 4.0 license
        • Article
        • Peer Reviewed
        UC Berkeley Previously Published Works (2018)

        Background

        Indoor residual spraying (IRS) of insecticides, conducted in low- and middle-income countries to control malaria, may result in high exposure to dichlorodiphenyltrichloroethane (DDT), its breakdown product dichlorodiphenyldichloroethylene (DDE), or pyrethroids. Animal studies suggest in utero exposure to these chemicals may increase childhood infection frequency.

        Objectives

        We investigated associations between maternal DDT/E and pyrethroid metabolite concentration and child infection associations in an IRS setting in which susceptibility factors are common and infections are leading causes of child morbidity and mortality.

        Methods

        Using gas chromatography-mass spectrometry, we measured serum DDT/E and urinary pyrethroid metabolite concentrations in peripartum samples from 674 women participating in the Venda Health Examination of Mother, Babies and their Environment (VHEMBE) study. Counts of persistent child fevers, otitis media, and severe sore throat between 1 and 2 y of age were ascertained from maternal interviews. Associations between DDT/E and pyrethroid metabolite concentrations and infections were estimated using zero-inflated Poisson regression. We estimated relative excess risks due to interaction (RERI) with poverty, maternal energy intake, and maternal HIV status.

        Results

        Concentrations of DDT/E, particularly p,p'-DDE, were associated with higher rates of persistent fevers [IRR=1.21 (95% CI: 1.01, 1.46)], for a 10-fold increase in p,p'-DDE). This association was stronger among children from households below versus above the South African food poverty line [IRR=1.31 (95% CI: 1.08, 1.59) vs. IRR=0.93 (95% CI: 0.69, 1.25), respectively] and for children whose mothers had insufficient versus sufficient caloric intake during pregnancy [IRR=1.30 (95% CI: 1.07, 1.58) vs. IRR=0.96 (95% CI: 0.72, 1.28), respectively].

        Conclusions

        In utero IRS insecticide exposure may increase childhood infection rates. This was particularly apparent among children from poorer households or whose mothers had low energy intake during pregnancy. https://doi.org/10.1289/EHP2657.
          Cover page: Maternal Peripartum Serum DDT/E and Urinary Pyrethroid Metabolite Concentrations and Child Infections at 2 Years in the VHEMBE Birth Cohort
          • Article
          • Peer Reviewed
          UCLA Previously Published Works (2022)
            • Article
            • Peer Reviewed
            UCLA Previously Published Works (2022)
              Cover page: IJE's Education Corner turns 10! Looking back and looking forward.
              • Article
              • Peer Reviewed
              UC Berkeley Previously Published Works (2018)

              Background

              Pyrethroids are the most widely used insecticides globally for domestic, agricultural, and malaria vector control. In 10 countries, dichlorodiphenyl trichloroethane (DDT) is also used for the latter. Thus, high exposure to pyrethroids and DDT have been reported among women and children from rural and/or malaria-endemic areas. Experimental studies suggest that fetal exposure to pyrethroids, particularly cypermethrin, and DDT may have sex-specific growth effects. However, epidemiologic investigations are scarce and inconsistent and have not considered postnatal environment or susceptibility factors.

              Methods

              In 665 mother-child dyads participating in the Venda Health Examination of Mothers, Babies, and their Environment (VHEMBE), a rural South African birth cohort with high insecticide exposure, we examined associations of maternal peripartum uri-nary pyrethroid metabolites and serum DDT concentrations with child anthropometrics at 3.5 years using multivariable linear regression. We investigated effect modification by child sex, maternal nutrition and HIV status, and household poverty.

              Results

              Pyrethroid metabolites cis-3-(2,2-dibromovinyl)-2,2-dimethyl-cyclopropane carboxylic acid (cis-DBCA), cis-3-(2,2,-dicholorvinyl)-2,2-dimethyl-cyclopropane carboxylic acid (cis-DCCA), trans-DCCA, and 3-phenoxybenzoic acid (3-PBA) were quantified in nearly all mothers. A 10-fold increase in cis-DCCA concentration was associated with 0.21 kg/m2 lower body mass index (95% confidence interval = -0.41, -0.01), with similar estimates for other cypermethrin or permethrin metabolites (trans-DCCA and 3-phenoxybenzoic acid). In stratified analyses, stronger associations were observed with lower weight, body mass index, arm circumference, and weight-for-height among boys relative to girls. Associations with cis-3-(2,2-dibromovinyl)-2,2-dimethyl-cyclopropane carboxylic acid, a metabolite specific to deltamethrin, were weaker or absent. No substantial associations were observed with DDT.

              Discussion

              In a population with ubiquitous pyrethroid exposure, maternal concentrations of metabolites of cypermethrin and permethrin were associated with thinness at 3.5 years.
                Cover page: Maternal peripartum urinary pyrethroid metabolites are associated with thinner children at 3.5 years in the VHEMBE birth cohort (Limpopo, South Africa)
                • Article
                • Peer Reviewed
                Western Journal of Emergency Medicine: Integrating Emergency Care with Population Health, Volume 19, Issue 1 (2018)

                Introduction: The emergency medicine clerkship curriculum at Los Angeles County + University of Southern California Medical Center includes monthly lectures on pediatric fever and shortness of breath (SOB). This educational innovation evaluated if learning could be enhanced by “priming” the students with educational online videos prior to an in-class session. Factors that impacted completion rates were also evaluated (planned specialty and time given for video viewing).

                Methods: Twenty minute videos were to be viewed prior to the didactic session. Students were assigned to either the fever or SOB group and received links to those respective videos. All participating students took a pre-test prior to viewing the online lectures. For analysis, test scores were placed into concordant groups (test results on fever questions in the group assigned the fever video and test results on SOB questions in the group assigned the SOB video) and discordant groups (crossover between video assigned and topic tested). Each subject contributed one set of concordant results and one set of discordant results. Descriptive statistics were performed with the Mann-Whitney U test. Lecture links were distributed to students two weeks prior to the in-class session for 7 months and three days prior to the in-class session for 8 months (in which both groups included both EM-bound and non-EM bound students).

                Results: In the 15 months study period, 64% of students rotating through the EM elective prepared for the in class session by watching the videos. During 10 months where exclusively EM-bound students were rotating (n=144), 71.5% of students viewed the lectures. In 4 months where students were not EM-bound (n=54), 55.6% of students viewed the lectures (p=0.033). Participation was 60.2% when lecture links were given three days in advance and 68.7% when links were given two weeks in advance (p=0.197). In the analysis of concordant scores, the pre-test averaged 56.7% correct, the immediate post-test averaged 78.1% correct, and the delayed post-test was 67.2%. In the discordant groups, the pretest averaged 51.9%, the immediate posttest was 67.1% and the delayed by 68.8%. In the concordant groups, the immediate post-test scores improved by 21.4%, compared with 15.2% in the discordant groups (p = 0.655). In the delayed post-test the concordant scores improved by 10.5% and discordant scores by 16.9 percent (p=0.609). Sixty-two percent of students surveyed preferred the format of online videos with in-class case discussion to a traditional lecture format.

                Conclusion: Immediate post-tests and delayed post-tests improved but priming was not demonstrated to be a statistically superior educational method in this study. Medical student completion of the preparatory materials for the emergency medicine rotation session increased when the students were emergency medicine-bound. Participation rates were not significantly different when given at 2 weeks versus 3 days.

                • 2 supplemental files
                Cover page: Flipping the Classroom in Medical Student Education: Does Priming Work?Creative Commons 'BY' version 4.0 license
                • Article
                • Peer Reviewed
                UC Berkeley Previously Published Works (2019)
                People typically rely heavily on visual information when finding their way to unfamiliar locations. For individuals with reduced vision, there are a variety of navigational tools available to assist with this task if needed. However, for wayfinding in unfamiliar indoor environments the applicability of existing tools is limited. One potential approach to assist with this task is to enhance visual information about the location and content of existing signage in the environment. With this aim, we developed a prototype software application, which runs on a consumer head-mounted augmented reality (AR) device, to assist visually impaired users with sign-reading. The sign-reading assistant identifies real-world text (e.g., signs and room numbers) on command, highlights the text location, converts it to high contrast AR lettering, and optionally reads the content aloud via text-to-speech. We assessed the usability of this application in a behavioral experiment. Participants with simulated visual impairment were asked to locate a particular office within a hallway, either with or without AR assistance (referred to as the AR group and control group, respectively). Subjective assessments indicated that participants in the AR group found the application helpful for this task, and an analysis of walking paths indicated that these participants took more direct routes compared to the control group. However, participants in the AR group also walked more slowly and took more time to complete the task than the control group. The results point to several specific future goals for usability and system performance in AR-based assistive tools.
                  • Article
                  • Peer Reviewed
                  UC Davis Previously Published Works (2022)
                  Developmental abnormalities in otoliths can impact growth and survival in teleost fishes. Here, we quantified the frequency and severity of developmental anomalies in otoliths of delta smelt (Hypomesus transpacificus), a critically endangered estuarine fish that is endemic to the San Francisco Estuary. Left-right asymmetry and anomalous crystalline polymorphs (i.e., vaterite) were quantified and compared between wild and cultured populations using digital image analysis. Visual estimates of vaterite were validated using X-ray diffraction, Raman spectroscopy, laser ablation ICPMS, and electron probe microanalysis. Results indicated that cultured delta smelt were 80 times more likely to contain a vateritic otolith and 18 times more likely to contain relatively large (≥ 15%) amounts of vaterite. Similarly, cultured fish exhibited 30% greater asymmetry than wild fish. These results indicate that cultured delta smelt exhibit a significantly higher frequency of vestibular abnormalities which are known to reduce fitness and survival. Such hatchery effects on otolith development could have important implications for captive culture practices and the supplementation of wild fish populations with cultured individuals.
                    Cover page: Visual, spectral, and microchemical quantification of crystalline anomalies in otoliths of wild and cultured delta smelt.Creative Commons 'BY' version 4.0 license
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