Publications by authors named "Kipruto Kirwa"

Exposure to PM is associated with adverse birth outcomes and early development. Pregnancy is typically characterized by the production of several important hormones that impact aspects of maternal and fetal physiology, including progesterone, estriol, and corticotropin releasing hormone (CRH). No previous studies have examined PM associations in pregnant persons for CRH and estriol.

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Introduction: This study investigates associations between fine particulate air pollution (PM) exposure and thyroid hormone levels during pregnancy in Puerto Rican individuals, a vulnerable population facing socioeconomic and environmental disparities.

Methods: This research draws on data from the PROTECT cohort study and involves 1040 participants to measure the effect of PM on developmentally important thyroid hormones (TSH, T3, T4, and FT4). Pollution concentrations were linked to participant locations using EPA air quality data and analyzed across two visits during gestational weeks 16-20 and 24-28.

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Background: Few epidemiologic studies have examined the association of ambient heat with spontaneous abortion, a common and devastating pregnancy outcome.

Methods: We conducted a case-crossover study nested within Pregnancy Study Online, a preconception cohort study (2013-2022). We included all participants reporting spontaneous abortion (N = 1,524).

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Background: Valid, high-resolution estimates of population-level exposure to air pollutants are necessary for accurate estimation of the association between air pollution and the occurrence or exacerbation of adverse health outcomes such as Chronic Obstructive Pulmonary Disease (COPD).

Objectives: We produced fine-scale individual-level estimates of ambient concentrations of multiple air pollutants (fine particulate matter [PM], NO, NO, and O) at residences of participants in the Subpopulations and Intermediate Outcomes in COPD Air Pollution (SPIROMICS Air) study, located in seven regions in the US. For PM, we additionally integrated modeled estimates of particulate infiltration based on home characteristics and measured total indoor concentrations to provide comprehensive estimates of exposure levels.

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Spontaneous abortion (SAB), defined as a pregnancy loss before 20 weeks of gestation, affects up to 30% of conceptions, yet few modifiable risk factors have been identified. We estimated the effect of ambient air pollution exposure on SAB incidence in Pregnancy Study Online (PRESTO), a preconception cohort study of North American couples who were trying to conceive. Participants completed questionnaires at baseline, every 8 weeks during preconception follow-up, and in early and late pregnancy.

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A growing body of literature has attempted to characterize how traffic-related air pollution (TRAP) affects molecular and subclinical biological processes in ways that could lead to cardiorespiratory disease. To provide a streamlined synthesis of what is known about the multiple mechanisms through which TRAP could lead to cardiorespiratory pathology, we conducted a systematic review of the epidemiological literature relating TRAP exposure to methylomic, proteomic, and metabolomic biomarkers in adult populations. Using the 139 papers that met our inclusion criteria, we identified the omic biomarkers significantly associated with short- or long-term TRAP and used these biomarkers to conduct pathway and network analyses.

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A growing body of literature has attempted to characterize how traffic-related air pollution (TRAP) affects molecular and subclinical biological processes in ways that could lead to cardiorespiratory disease. To provide a streamlined synthesis of what is known about the multiple mechanisms through which TRAP could lead cardiorespiratory pathology, we conducted a systematic review of the epidemiological literature relating TRAP exposure to methylomic, proteomic, and metabolomic biomarkers in adult populations. Using the 139 papers that met our inclusion criteria, we identified the omic biomarkers significantly associated with short- or long-term TRAP and used these biomarkers to conduct pathway and network analyses.

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Article Synopsis
  • Air pollution has potential adverse effects on fertility, but evidence is limited and varies across studies, making it unclear which specific pollutants are responsible.
  • The study analyzed data from 8,747 fertility planners in the U.S. and Canada, focusing on the impact of different air pollutants on their chances of conceiving during a one-year period.
  • Results showed no significant association between key pollutants like particulate matter, nitrogen dioxide, and ozone with fecundability rates in both countries, indicating that air pollution may not strongly influence fertility outcomes.
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Article Synopsis
  • Residential green space has been linked to various health benefits, including potentially improving fertility rates, though research on this specific connection is limited.
  • The study analyzed data from 8,563 women trying to conceive, assessing the impact of green space on fecundability using geographic data and statistical models.
  • Findings indicated that higher levels of green space (measured through NDVI) were associated with a greater probability of conception, particularly in annual and seasonal maximum models, but results were less significant for average seasonal exposure.
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Background: Based on human and animal experimental studies, exposure to ambient carbon monoxide (CO) may be associated with cardiovascular disease outcomes, but epidemiological evidence of this link is limited. The number and distribution of ground-level regulatory agency monitors are insufficient to characterize fine-scale variations in CO concentrations.

Objectives: To develop a daily, high-resolution ambient CO exposure prediction model at the city scale.

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Importance: Decades of inequitable policies in the US have yielded disparities in neighborhood quality, and some studies show that living in a socioeconomically disadvantaged neighborhood is associated with worse health outcomes, including reproductive health outcomes. However, no US studies to date have directly examined the association between residence in disadvantaged neighborhoods and fertility.

Objective: To examine the association between residence in disadvantaged neighborhoods and fecundability, a sensitive marker of fertility with many health implications.

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Background: Up to 30% of pregnancies end in spontaneous abortion, yet few risk factors have been identified. Examining seasonal patterns in risk of spontaneous abortion can generate new hypotheses regarding environmental and lifestyle determinants.

Methods: We used data from Pregnancy Study Online-a preconception cohort study of pregnancy planners from the United States and Canada-to examine seasonal variation in spontaneous abortion risk.

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Background: Preterm birth (PTB, birth before 37 weeks of gestation) has been associated with adverse health outcomes across the lifespan. Evidence on the association between PTB and prenatal exposure to air pollutants is inconsistent, and is especially lacking for ethnic/racial minority populations.

Methods: We obtained data on maternal characteristics and behaviors and PTB and other birth outcomes for women participating in the Puerto Rico Testsite for Exploring Contamination Threats (PROTECT) cohort, who lived in municipalities located along the North Coast of Puerto Rico.

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Article Synopsis
  • The review highlights the evolution of exposure assessment in air pollution studies, focusing on spatiotemporal techniques developed during the MESA Air project, which allow for a detailed understanding of pollution variations in urban areas.
  • Recent advancements in modeling techniques enable the prediction of pollutant levels, such as PM, nitrogen oxides, and ozone, at specific locations and timeframes (e.g., residential addresses over two weeks) across the contiguous USA from 1980 to now.
  • These modern models improve upon past methods by using better statistical approaches and integrating diverse data sources, leading to more accurate insights into the health impacts of air pollution throughout people's lives.
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Air pollution has been shown to impact multiple measures of neurodevelopment in young children. Its effects on particularly vulnerable populations, such as ethnic minorities, however, is less studied. To address this gap in the literature, we assess the associations between infant non-nutritive suck (NNS), an early indicator of central nervous system integrity, and air pollution exposures in Puerto Rico.

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Unlabelled: Emerging evidence from animal and human studies indicates that exposure to traffic-related air pollution may adversely affect fertility.

Methods: Among 7,342 female pregnancy planners from the United States and 1,448 from Canada, we examined the association between residential proximity to major roads and fecundability, the per-cycle probability of conception. From 2013 to 2019, women 21-45 years old who were trying to conceive without fertility treatment completed an online baseline questionnaire and follow-up questionnaires every 8 weeks for up to 12 months or until pregnancy.

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Background: Increasingly studies suggest prenatal exposure to air pollution may increase risk of childhood asthma. Few studies have investigated exposure during specific fetal pulmonary developmental windows.

Objective: To assess associations between prenatal fine particulate matter exposure and asthma at age 4.

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Background: Air pollution may affect the risk of respiratory infection, though research has focused on uncommon infections or infections in children. Whether ambient air pollutants increase the risk of common acute respiratory infections among adults is uncertain, yet this may help understand whether pollutants influence spread of pandemic respiratory infections like COVID-19.

Objective: To estimate the association between ambient air pollutant exposures and respiratory infections in adults.

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For people living with HIV (PLWH), patient transfers may affect engagement in care. We followed a cohort of PLWH in Cape Town, South Africa who tested positive for HIV in 2012-2013 from ART initiation in 2012-2016 through December 2016. Patient transfers were defined as moving from one healthcare facility to another on a different day, considering all healthcare visits and recorded HIV-visits only.

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Increased outdoor concentrations of fine particulate matter (PM ) and oxides of nitrogen (NO , NO ) are associated with respiratory and cardiovascular morbidity in adults and children. However, people spend most of their time indoors and this is particularly true for individuals with chronic obstructive pulmonary disease (COPD). Both outdoor and indoor air pollution may accelerate lung function loss in individuals with COPD, but it is not feasible to measure indoor pollutant concentrations in all participants in large cohort studies.

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Background: Estimates of retention in antiretroviral treatment (ART) programmes may be biased if patients who transfer to healthcare clinics are misclassified as lost to follow-up (LTFU) at their original clinic. In a large cohort, we estimated retention in care accounting for patient transfers using medical records.

Methods: Using linked electronic medical records, we followed adults living with HIV (PLWH) in Cape Town, South Africa from ART initiation (2012-2016) through database closure at 36 months or 30 June 2016, whichever came first.

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Background: Low birth weight (LBW) has been associated with adverse health outcomes across the lifespan. Among ethnic/racial minority populations, few studies have examined the association between LBW (<2,500 or ≥2,500 g) and prenatal exposure to air pollution, a key modifiable environmental risk factor.

Methods: We examined the association between LBW and prenatal exposure to PM in a Hispanic and black population in Puerto Rico between 1999 and 2013, adjusting for individual and municipality-level confounders.

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Importance: Few studies have investigated the association of long-term ambient ozone exposures with respiratory morbidity among individuals with a heavy smoking history.

Objective: To investigate the association of historical ozone exposure with risk of chronic obstructive pulmonary disease (COPD), computed tomography (CT) scan measures of respiratory disease, patient-reported outcomes, disease severity, and exacerbations in smokers with or at risk for COPD.

Design, Setting, And Participants: This multicenter cross-sectional study, conducted from November 1, 2010, to July 31, 2018, obtained data from the Air Pollution Study, an ancillary study of SPIROMICS (Subpopulations and Intermediate Outcome Measures in COPD Study).

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