Skip to main content
eScholarship
Open Access Publications from the University of California

Scholarly Works (5 results)

  • Thesis
  • Peer Reviewed
UC Merced Electronic Theses and Dissertations (2022)

Background: Global environmental chemical exposure is expected to grow but its impacts on fertility is unclear. Objectives: We characterized exposures to 23 common chemicals across socioeconomic characteristics and examined their relationship with self-reported infertility. Methods: Non-pregnant women ages 18–49 years without history of hysterectomy or oophorectomy (n = 2,579) were identified from the National Health and Nutrition Examination Survey (2013–2016). Sociodemographic factors and infertility were self-reported. Environmental chemicals were analyzed from biospecimens and dichotomized as high and low based on the median. Logistic regression models estimated the odds ratio (OR) and 95% confidence intervals (CI) for the association between high exposures and infertility. Results: Women who were older, of other/multi-race, and less educated had higher exposures to chemicals such as pesticides, heavy metals, and flame retardants. There were associations between infertility with cadmium (aOR: 1.83 95% CI: 1.00 – 3.63) and arsenic (aOR: 1.92 95% CI: 1.07-3.44), and two pesticides including hexachlorobenzene (OR: 2.04 95% CI: 1.05-3.98) and oxychlordane (OR: 2.04 (1.12-3.69). Only cadmium and arsenic remain statistically significant in adjusted models. We also found negative associations with two Per- and Polyfluoroalkyl substances. Conclusions: Chemical exposures varied by sociodemographic characteristics. Associations were mixed and unstable due to small sample, but cadmium and arsenic were associated with infertility.

  • 1 supplemental PDF
Cover page: Exposure to environmental chemicals and infertility among US reproductive-aged womenCreative Commons 'BY-NC-ND' version 4.0 license
  • Thesis
  • Peer Reviewed
UC Merced Electronic Theses and Dissertations (2024)

Background: Despite the decrease in overall pollution levels across California, the San Joaquin Valley (SJV) remains a non-attainment area for pollutants including PM2.5 and O3. Objectives: We assessed the association between acute exposure to PM2.5 and O3 and the risk of fetal and infant death in the SJV. Methods: This time-stratified case-crossover analysis includes 1,343 singleton fetal deaths and 1,097 singleton infant deaths in the SJV from 2016 to 2019. Daily O3 and PM2.5 data were geospatially linked to the residential zip codes of mothers at delivery. We examined critical exposure windows including the day of death (lag 0) and the 14 days leading up to it (lag 1 - lag 14). We used conditional logistic regression models to calculate the odds ratio (OR) and 95% confidence intervals for each 10-unit increase in pollutants. Results: PM2.5 during cold (November-April) and O3 during warm seasons (May-October) were positively associated with higher odds of fetal and infant deaths. O3 was positively associated with both fetal and infant deaths across all lags while no significant associations were observed between infant death and PM2.5 exposure. Associations also varied across racial, and socio-economic divisions and maternal ages. Conclusions: As climate change escalates, rising air pollution may contribute to perinatal mortality.

    Cover page: Acute impact of air pollution on fetal and infant death in the San Joaquin Valley, California: A time-stratified case-crossover
    • Article
    • Peer Reviewed
    UC Merced Previously Published Works (2022)
    The strategic use of media is a common approach to promote health. A large body of evidence identifies specific features that increase message efficacy, including tailoring messages to the target audience and using a storytelling format. Yet most message testing research has focused on individual-level outcomes, ignoring the social and environmental determinants of health behaviors, which require collective action and political will to change. Grounded in an ecological approach to communication, we will carry out two double-blinded randomized experiments to test the relative effectiveness of message tailoring (culturally-tailored vs. standard) and format (narrative vs. didactic) to increase the intention to reduce individual sugar-sweetened beverage consumption, the understanding of social and commercial determinants of health, and the sense of empowerment among young adult Latinas. Based on power analyses (80% power at alpha = 0.05), we will randomize 438 participants to two groups (traditional standard infographic and culturally-tailored infographic) in the first study, and 662 participants to two groups (culturally-tailored infographic and culturally-tailored comic book) in the second study. All participants will be measured by a pre-treatment test and an immediate post-treatment test. We hypothesize that culturally-tailored comic book will be most effective, and traditional standard infographic will be least effective, on all levels of outcomes. This study will provide empirical evidence in communication strategies to help young Latinos or other racial/ethnic minority young people to pursue positive dietary behaviors that both benefit themselves and contribute to change of social norms.
      Cover page: Protocol: Effectiveness of message content and format on individual and collective efficacy in reducing the intention to consume sugar-sweetened beverages
      • Article
      • Peer Reviewed
      UC Merced Previously Published Works (2021)

      Purpose

      This study examines risk factors for heat-related mortality due to hyperthermia in emergency department patients, a vulnerable population.

      Methods

      This matched case-control study used statewide, longitudinally linked emergency department (ED) data and death records from California. Cases comprised California residents (≥18 years) who presented to a state-licensed ED and died of hyperthermia during the study period (2009-2012). For each case, up to five ED patients were randomly selected as live controls and matched on sex and age. Patients' demographic characteristics and history of ED utilization for alcohol use, drug use, psychiatric disorders, heart-related conditions, chronic respiratory disease, neurodegenerative disorders, and cerebrovascular disease were assessed in relationship to hyperthermia mortality.

      Results

      Using multivariate conditional logistic regression models, hyperthermia mortality cases had higher odds of prior ED utilization for alcohol use (OR = 11.16, 95% CI = 3.87, 32.17) compared to controls. Cases were also more likely than controls to have Medicare insurance (OR = 5.80, 95% CI = 1.70, 15.15) or self-pay (OR = 5.39, 95% CI = 1.73, 16.79), at their most recent ED visit.

      Conclusions

      ED patients presenting with alcohol problems may face increased risk of hyperthermia mortality. To help reduce heat-related mortality, EDs should consider interventions that target patients vulnerable to heat exposure.
        Cover page: Risk factors for hyperthermia mortality among emergency department patients
        • Article
        • Peer Reviewed
        UC Merced Previously Published Works (2019)

        Background

        Residential proximity to major roadways, and prenatal exposures to particulate matter <2.5 μm (PM2.5) and ozone (O3) are linked to poor fetal outcomes but their relationship with childhood development is unclear.

        Objectives

        We investigated whether proximity to major roadways, or prenatal and early-life exposures to PM2.5 and O3 increase the risk of early developmental delays.

        Study design

        Prospective cohort.

        Settings

        New York State excluding New York City.

        Participants

        4089 singletons and 1016 twins born between 2008 and 2010.

        Exposures

        Proximity to major roadway was calculated using road network data from the NY Department of Transportation. Concentrations of PM2.5 and O3 estimated by the Environmental Protection Agency Downscaler models were spatiotemporally linked to each child's prenatal and early-life addresses incorporating residential history, and locations of maternal work and day-care.

        Outcomes

        Parents reported their children's development at ages 8, 12, 18, 24, 30 and 36 months in five domains using the Ages and Stages Questionnaire. Generalized mixed models estimated the relative risk (RR) and 95% CI for failing any developmental domain per 10 units increase in PM2.5 and O3, and for those living <1000 m away from a major roadway compared to those living further. Models adjusted for potential confounders.

        Results

        Compared to those >1000 m away from a major roadway, those resided 50-100 m [RR: 2.12 (1.00-4.52)] and 100-500 m [RR: 2.07 (1.02-4.22)] away had twice the risk of failing the communication domain. Prenatal exposures to both PM2.5 and ozone during various pregnancy windows had weak but significant associations with failing any developmental domain with effects ranging from 1.6% to 2.7% for a 10 μg/m3 increase in PM2.5 and 0.7%-1.7% for a 10 ppb increase in ozone. Average daily postnatal ozone exposure was positively associated with failing the overall screening by 8 months [3.3% (1.1%-5.5%)], 12 months [17.7% (10.4%-25.5%)], and 30 months [7.6%, (1.3%-14.3%)]. Findings were mixed for postnatal PM2.5 exposures.

        Conclusions

        In this prospective cohort study, proximity to major roadway and prenatal/early-life exposures to PM2.5 and O3 were associated with developmental delays. While awaiting larger studies with personal air pollution assessment, efforts to minimize air pollution exposures during critical developmental windows may be warranted.
          Cover page: Prenatal and early life exposures to ambient air pollution and development
          Top