Severe COVID-19 patients exhibit elevated levels of autoantibodies targeting cardiolipin and platelet glycoprotein with age: a systems biology approach.

Age is a significant risk factor for the coronavirus disease 2019 (COVID-19) severity due to immunosenescence and certain age-dependent medical conditions (e.g., obesity, cardiovascular disorder, and chronic respiratory disease). However, despite the well-known influence of age on autoantibody biology in health and disease, its impact on the risk of developing severe COVID-19 remains poorly explored. Here, we performed a cross-sectional study of autoantibodies directed against 58 targets associated with autoimmune diseases in 159 individuals with different COVID-19 severity (71 mild, 61 moderate, and 27 with severe symptoms) and 73 healthy controls. We found that the natural production of autoantibodies increases with age and is exacerbated by SARS-CoV-2 infection, mostly in severe COVID-19 patients. Multiple linear regression analysis showed that severe COVID-19 patients have a significant age-associated increase of autoantibody levels against 16 targets (e.g., amyloid ß peptide, ß catenin, cardiolipin, claudin, enteric nerve, fibulin, insulin receptor a, and platelet glycoprotein). Principal component analysis with spectrum decomposition and hierarchical clustering analysis based on these autoantibodies indicated an age-dependent stratification of severe COVID-19 patients. Random forest analysis ranked autoantibodies targeting cardiolipin, claudin, and platelet glycoprotein as the three most crucial autoantibodies for the stratification of severe COVID-19 patients ≥50 years of age. Follow-up analysis using binomial logistic regression found that anti-cardiolipin and anti-platelet glycoprotein autoantibodies significantly increased the likelihood of developing a severe COVID-19 phenotype with aging. These findings provide key insights to explain why aging increases the chance of developing more severe COVID-19 phenotypes.

Cross-sectional analysis reveals autoantibody signatures associated with COVID-19 severity.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is associated with increased levels of autoantibodies targeting immunological proteins such as cytokines and chemokines. Reports further indicate that COVID-19 patients may develop a broad spectrum of autoimmune diseases due to reasons not fully understood. Even so, the landscape of autoantibodies induced by SARS-CoV-2 infection remains uncharted territory. To gain more insight, we carried out a comprehensive assessment of autoantibodies known to be linked to diverse autoimmune diseases observed in COVID-19 patients in a cohort of 231 individuals, of which 161 were COVID-19 patients (72 with mild, 61 moderate, and 28 with severe disease) and 70 were healthy controls. Dysregulated IgG and IgA autoantibody signatures, characterized mainly by elevated concentrations, occurred predominantly in patients with moderate or severe COVID-19 infection. Autoantibody levels often accompanied anti-SARS-CoV-2 antibody concentrations while stratifying COVID-19 severity as indicated by random forest and principal component analyses. Furthermore, while young versus elderly COVID-19 patients showed only slight differences in autoantibody levels, elderly patients with severe disease presented higher IgG autoantibody concentrations than young individuals with severe COVID-19. This work maps the intersection of COVID-19 and autoimmunity by demonstrating the dysregulation of multiple autoantibodies triggered during SARS-CoV-2 infection. Thus, this cross-sectional study suggests that SARS-CoV-2 infection induces autoantibody signatures associated with COVID-19 severity and several autoantibodies that can be used as biomarkers of COVID-19 severity, indicating autoantibodies as potential therapeutical targets for these patients.

Dysregulated Levels of Circulating Autoantibodies against Neuronal and Nervous System Autoantigens in COVID-19 Patients.

BACKGROUND: COVID-19 is a heterogenous disease resulting in long-term sequela in predisposed individuals. It is not uncommon that recovering patients endure non-respiratory ill-defined manifestations, including anosmia, and neurological and cognitive deficit persisting beyond recovery-a constellation of conditions that are grouped under the umbrella of long-term COVID-19 syndrome. Association between COVID-19 and autoimmune responses in predisposed individuals was shown in several studies. AIM AND METHODS: To investigate autoimmune responses against neuronal and CNS autoantigens in SARS-CoV-2-infected patients, we performed a cross-sectional study with 246 participants, including 169 COVID-19 patients and 77 controls. Levels of antibodies against the acetylcholine receptor, glutamate receptor, amyloid ß peptide, alpha-synucleins, dopamine 1 receptor, dopamine 2 receptor, tau protein, GAD-65, N-methyl D-aspartate (NMDA) receptor, BDNF, cerebellar, ganglioside, myelin basic protein, myelin oligodendrocyte glycoprotein, S100-B, glial fibrillary acidic protein, and enteric nerve were measured using an Enzyme-Linked Immunosorbent Assay (ELISA). Circulating levels of autoantibodies were compared between healthy controls and COVID-19 patients and then classified by disease severity (mild [n = 74], severe [n = 65], and requiring supplemental oxygen [n = 32]). RESULTS: COVID-19 patients were found to have dysregulated autoantibody levels correlating with the disease severity, e.g., IgG to dopamine 1 receptor, NMDA receptors, brain-derived neurotrophic factor, and myelin oligodendrocyte glycoprotein. Elevated levels of IgA autoantibodies against amyloid ß peptide, acetylcholine receptor, dopamine 2 receptor, myelin basic protein, and α-synuclein were detected in COVID-19 patients compared with healthy controls. Lower IgA autoantibody levels against NMDA receptors, and IgG autoantibodies against glutamic acid decarboxylase 65, amyloid ß peptide, tau protein, enteric nerve, and S100-B were detected in COVID-19 patients versus healthy controls. Some of these antibodies have known clinical correlations with symptoms commonly reported in the long COVID-19 syndrome. CONCLUSIONS: Overall, our study shows a widespread dysregulation in the titer of various autoantibodies against neuronal and CNS-related autoantigens in convalescent COVID-19 patients. Further research is needed to provide insight into the association between these neuronal autoantibodies and the enigmatic neurological and psychological symptoms reported in COVID-19 patients.

Predictors of chronic COVID-19 symptoms in a community-based cohort of adults.

BACKGROUND: COVID-19 can cause some individuals to experience chronic symptoms. Rates and predictors of chronic COVID-19 symptoms are not fully elucidated. OBJECTIVE: To examine occurrence and patterns of post-acute sequelae of SARS-CoV2 infection (PASC) symptomatology and their relationship with demographics, acute COVID-19 symptoms and anti-SARS-CoV-2 IgG antibody responses. METHODS: A multi-stage observational study was performed of adults (≥18 years) from 5 US states. Participants completed two rounds of electronic surveys (May-July 2020; April-May 2021) and underwent testing to anti-SARS-CoV-2 nucleocapsid protein IgG antibody testing. Latent Class Analysis was used to identify clusters of chronic COVID-19 symptoms. RESULTS: Overall, 390 adults (median [25%ile, 75%ile] age: 42 [31, 54] years) with positive SARS-CoV-2 antibodies completed the follow-up survey; 92 (24.7%) had ≥1 chronic COVID-19 symptom, with 11-month median duration of persistent symptoms (range: 1-12 months). The most common chronic COVID-19 symptoms were fatigue (11.3%), change in smell (9.5%) or taste (5.6%), muscle or joint aches (5.4%) and weakness (4.6%). There were significantly higher proportions of ≥1 persistent COVID-19 symptom (31.5% vs. 18.6%; Chi-square, P = 0.004), and particularly fatigue (15.8% vs. 7.3%, P = 0.008) and headaches (5.4% vs. 1.0%, P = 0.011) in females compared to males. Chronic COVID-19 symptoms were also increased in individuals with ≥6 acute COVID-19 symptoms, Latent class analysis revealed 4 classes of symptoms. Latent class-1 (change of smell and taste) was associated with lower anti-SARS-CoV-2 antibody levels; class-2 and 3 (multiple chronic symptoms) were associated with higher anti-SARS-CoV-2 antibody levels and more severe acute COVID-19 infection. LIMITATIONS: Ambulatory cohort with less severe acute disease. CONCLUSION: Individuals with SARS-CoV-2 infection commonly experience chronic symptoms, most commonly fatigue, changes in smell or taste and muscle/joint aches. Female sex, severity of acute COVID-19 infection, and higher anti-SARS-CoV-2 IgG levels were associated with the highest risk of having chronic COVID-19 symptoms.

Autoantibodies targeting GPCRs and RAS-related molecules associate with COVID-19 severity.

COVID-19 shares the feature of autoantibody production with systemic autoimmune diseases. In order to understand the role of these immune globulins in the pathogenesis of the disease, it is important to explore the autoantibody spectra. Here we show, by a cross-sectional study of 246 individuals, that autoantibodies targeting G protein-coupled receptors (GPCR) and RAS-related molecules associate with the clinical severity of COVID-19. Patients with moderate and severe disease are characterized by higher autoantibody levels than healthy controls and those with mild COVID-19 disease. Among the anti-GPCR autoantibodies, machine learning classification identifies the chemokine receptor CXCR3 and the RAS-related molecule AGTR1 as targets for antibodies with the strongest association to disease severity. Besides antibody levels, autoantibody network signatures are also changing in patients with intermediate or high disease severity. Although our current and previous studies identify anti-GPCR antibodies as natural components of human biology, their production is deregulated in COVID-19 and their level and pattern alterations might predict COVID-19 disease severity.

SARS-CoV-2 Infection in Winter 2021/2022: The Association of Varying Clinical Manifestations With and Without Prior Vaccination.

Importance SARS-CoV-2 is a rapidly evolving virus with many strains. Although vaccines have proven to be effective against earlier strains of the virus, the efficacy of vaccination status against later strains is still an area of active research. Objective To determine if vaccination status was associated with symptomatology due to infection by later strains of SARS-CoV-2. Design This cross-sectional survey was sent to an adult Jewish population from December 2021 to March 2022. Setting This is a population-based study of Jewish communities throughout the tristate area. The subjects were recruited by local Jewish not-for-profit and social service organizations. Participants Surveys were sent to 14,714 adults who were recruited by local Jewish not-for-profit and social service organizations; 966 respondents completed the survey (6.57%). Only participants who received a positive COVID-19 nasal swab 10 weeks since December 1, 2021, were included in the main outcome. Exposure Participants were grouped by vaccine type (i.e., Johnson & Johnson {J&J}, Moderna, or Pfizer) and vaccination status (i.e., unvaccinated, single, full, or booster). Main outcomes and measures The primary study outcome was an association between immunization status and somatological presentation. Symptom severity classes were built using latent class analysis (LCA). Results Out of 14,714 recipients, 966 completed the survey (6.57%). The participants were mainly self-described Ashkenazi Jewish (97%) with a median age of 41. The LCA resulted in four classes: highly symptomatic (HS), less symptomatic (LS), anosmia, and asymptomatic (AS). Vaccinated participants were less likely to be in symptomatic groups than the unvaccinated participants (odds ratio {OR}: 0.326; 95% confidence interval {CI}: 0.157-0.679; p=0.002). Boosted participants were less likely to be in symptomatic groups than fully vaccinated participants (OR: 0.267; 95% CI: 0.122-0.626; p=0.002). Additionally, there was no association between symptomatology and vaccination type (p=0.353). Conclusions and relevance Participants who received COVID-19 vaccinations or booster shots were less likely to be symptomatic after Omicron infection compared to unvaccinated participants and vaccinated participants without boosters, respectively. There's no association between vaccination type and symptomatology. These results enhance our understanding that COVID-19 vaccinations improve clinical symptomatology, even in an unforeseen COVID-19 strain.

Association of Varying Clinical Manifestations and Positive Anti-SARS-CoV-2 IgG Antibodies: A Cross-Sectional Observational Study.

BACKGROUND: The complex relationship between clinical manifestations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and individual immune responses is not fully elucidated. OBJECTIVE: To examine phenotypes of symptomatology and their relationship with positive anti-SARS-CoV-2 IgG antibody responses. METHODS: An observational study was performed of adults (≥18 years) from 5 US states. Participants completed an electronic survey and underwent testing to anti-SARS-CoV-2 nucleocapsid protein IgG antibody between May and July 2020. Latent class analysis was used to identify characteristic symptom clusters. RESULTS: Overall, 9507 adults (mean age, 39.6 ± 15.0 years) completed the survey; 6665 (70.1%) underwent antibody testing for anti-SARS-CoV-2 IgG. Positive SARS-CoV-2 antibodies were associated with self-reported positive SARS-CoV-2 nasal swab result (bivariable logistic regression; odds ratio [95% CI], 5.98 [4.83-7.41]), household with 6 or more members (1.27 [1.14-1.41]) and sick contact (3.65 [3.19-4.17]), and older age (50-69 years: 1.55 [1.37-1.76]; ≥70 years: 1.52 [1.16-1.99]), but inversely associated with female sex (0.61 [0.55-0.68]). Latent class analysis revealed 8 latent classes of symptoms. Latent classes 1 (all symptoms) and 4 (fever, cough, muscle ache, anosmia, dysgeusia, and headache) were associated with the highest proportion (62.0% and 57.4%) of positive antibodies, whereas classes 6 (fever, cough, muscle ache, headache) and 8 (anosmia, dysgeusia) had intermediate proportions (48.2% and 40.5%), and classes 3 (headache, diarrhea, stomach pain) and 7 (no symptoms) had the lowest proportion (7.8% and 8.5%) of positive antibodies. CONCLUSIONS: SARS-CoV-2 infections manifest with substantial diversity of symptoms, which are associated with variable anti-SARS-CoV-2 IgG antibody responses. Prolonged fever, anosmia, and receiving supplemental oxygen therapy had strongest associations with positive SARS-CoV-2 IgG.

SARS-CoV-2 Seroprevalence and Symptom Onset in Culturally Linked Orthodox Jewish Communities Across Multiple Regions in the United States.

Importance: Data on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence in the United States are still emerging. Objective: To elucidate SARS-CoV-2 seroprevalence and symptom onset in a culturally linked community across 5 states in the United States. Design, Setting, and Participants: This cross-sectional study included adults (aged ≥18 years) recruited from the orthodox Jewish community across 5 states (California, Connecticut, Michigan, New Jersey, and New York) in 3 geographically distinct areas of the United States between May 13 and July 6, 2020. Participants completed an online survey and underwent SARS-CoV-2 antibody testing. Main Outcomes and Measures: Seroprevalence and date of symptom onset of SARS-CoV-2. Results: Overall, 9507 adults (mean [SD] age, 39.6 [15.0] years; 3777 [39.7%] women) completed the SARS-CoV-2 survey, of whom 6665 (70.1%) had immunoglobin G anti-SARS-CoV-2 antibody levels assessed. A high seroprevalence of SARS-CoV-2 antibodies was observed across all communities, with the highest proportion of positive testing observed in New Jersey (1080 of 3323 [32.5%]) and New York (671 of 2196 [30.6%]). Most individuals with a positive SARS-CoV-2 immunoglobin G antibody test reported a date of symptom-onset between March 9 and March 31, 2020 (California: 135 of 154 [87.7%]; Connecticut: 32 of 34 [94.1%]; Michigan: 44 of 50 [88.0%]; New Jersey: 964 of 1168 [82.5%]; New York: 571 of 677 [84.3%]). This start date was coincident with the Jewish festival of Purim, celebrated March 9 to 10, 2020, with extensive intracommunity spread in the weeks following (mean and mode of peak symptom onset, March 20, 2020), occurring in the absence of strong general and culture-specific public health directives. Conclusions and Relevance: This cross-sectional study of orthodox Jewish adults across the US found that socioculturally bound communities experienced early parallel outbreaks in discrete locations, notably prior to substantive medical and governmental directives. Further research should clarify optimal national, local, community-based, and government policies to prevent outbreaks in social and cultural communities that traditionally gather for holidays, assemblies, and festivals.

Reliability of upper airway assessment using CBCT.

Background: Upper airway analysis is an often-cited use of CBCT imaging by orthodontists; however, the reliability of airway measurements using this technology is not fully established. Objective: To determine the intra-examiner and inter-examiner reliability of the complete process of volumetric and cross-sectional area assessments of the upper airway using CBCT imaging. Materials and Methods: Six examiners of varying levels of education and clinical experience performed the steps necessary for airway analysis, including manual orientation, slice and threshold selection and measured nasopharyngeal, oropharyngeal, hypopharyngeal and total upper pharyngeal airway volumes in addition to minimum cross-sectional area on the CBCT images of 10 patients. All measurements were repeated after 4-weeks. Intra- and inter-examiner reliability was calculated using ICC and 95% CI. Results: Threshold selection showed poor intra- and poor inter-examiner reliability, whereas minimum cross-sectional area showed moderate intra- and poor inter-examiner reliability. Intra-examiner reliability of volumetric measurements varied based on the region assessed with ICC ranging from 0.747 to 0.976, and was worst for hypopharynx and best for the oropharynx. Inter-examiner reliability of volume measurements was generally lower, with ICC ranging from 0.175 to 0.945, and was worst for nasopharynx and best for the oropharynx. Conclusions: This study, for the first time, assessed the reliability of upper airway analysis with CBCT when all steps of image processing and measurement are performed by each examiner. Reliability improved with examiner experience, though was generally low for the hypopharynx and nasopharynx volumes and overall minimal cross-sectional area. The oropharyngeal volume was the only parameter to have excellent intra- and inter-examiner reliability.

Reliability of upper pharyngeal airway assessment using dental CBCT: a systematic review.

BACKGROUND: Upper airway analysis is an often-cited use of cone beam computed tomography (CBCT) imaging in orthodontics. However, the reliability of this process in a clinical setting is largely unknown. OBJECTIVE: Our objective was to systematically review the literature to evaluate the reliability of upper pharyngeal airway assessment using dental CBCT. SEARCH METHODS: MEDLINE, EMBASE, Web of Science, and Google Scholar were searched through June 2015. SELECTION CRITERIA: Human studies that measured reliability of upper airway assessment in patients using CBCT as part of the study protocol were considered. DATA COLLECTION AND ANALYSIS: The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) was followed. Data were collected on overall study characteristics and measurements, CBCT unit and machine settings used, and examination characteristics of the included studies. Methodological quality of the included studies was evaluated. RESULTS: Forty-two studies were evaluated, representing the CBCT scans of 956 patients. Studies included a wide variety of patients and CBCT machines with various scan settings. Only five studies were deemed high quality. The available evidence indicates that under specific restricted conditions there is moderate to excellent intra- and inter-examiner reliability. Airway volume demonstrated greater intra- and inter-examiner reliability than did minimum cross-sectional area. However, significant methodological limitations of the current literature, most importantly a lack of manual orientation of the images and selection of threshold sensitivity in study protocols, suggest that reliability has not been adequately established. CONCLUSIONS: The current literature reports moderate to excellent reliability, with airway volume having higher reliability than minimum cross-sectional area. However, only limited aspects of the process of airway analysis have been evaluated, indicating that further research is required to adequately establish the reliability of upper pharyngeal airway assessment of patients using dental CBCT. REGISTRATION: None.

Risk of thromboembolic events after protocolized warfarin reversal with 3-factor PCC and factor VIIa.

Bleeding events and life-threatening hemorrhage are the most feared complications of warfarin therapy. Prompt anticoagulant reversal aimed at replacement of vitamin K-dependent clotting factors is essential to promote hemostasis. A retrospective cohort study of warfarin-treated patients experiencing a life-threatening hemorrhage treated with an institution-specific warfarin reversal protocol (postimplementation group) and those who received the prior standard of care (preimplementation group) was performed. The reversal protocol included vitamin K, 3-factor prothrombin complex concentrate, and recombinant factor VIIa. Demographic and clinical information, anticoagulant reversal information, and all adverse events attributed to warfarin reversal were recorded. A total of 227 patients were included in final analysis, 109 in the preimplementation group and 118 in the postimplementation group. Baseline patient characteristics were similar in both groups, with the exception of higher average Sequential Organ Failure Assessment scores in the postimplementation group (P = .0005). The most common indication for anticoagulation reversal was intraparenchymal hemorrhage. Prereversal international normalized ratios (INRs) were similar in both groups. Attainment of INR normalization to less than 1.4 was higher, and rebound INR was lower in the postimplementation group (P < .0001; P = .0013). Thromboembolic complications were significantly higher in the postimplementation group (P = .003). Elevated baseline Sequential Organ Failure Assessment score and mechanical valve as an indication for anticoagulation were independently associated with thrombotic complications (P = .005). A warfarin reversal protocol consisting of 3-factor prothrombin complex concentrate, recombinant factor VIIa, and vitamin K more consistently normalized INR values to less than 1.4 as compared to the prior standard of care in a diverse patient population. This success came at the cost of a 2-fold increase in risk of thromboembolic complications.

Proteomic evaluation of acquired enamel pellicle during in vivo formation.

Acquired enamel pellicle (AEP) is a protein film that forms on the enamel surface of teeth by selective adsorption of proteins and peptides present in the mouth. This protein film forms the interface between enamel and the damage oral biofilm, which modulates the attachment of bacteria found in oral biofilm. The overall goal of this study was to gain insight into the biological formation of the human in vivo AEP. This study hypothesized that AEP is created by the formation of successive protein layers, which consist of initial binding to enamel and subsequent protein-protein interactions. This hypothesis was examined by observing quantitative and qualitative changes in pellicle composition during the first two hours of AEP formation in the oral cavity. Quantitative mass spectrometry approaches were used to generate an AEP protein profile for each time-point studied. Relative proteomic quantification was carried out for the 50 proteins observed in all four time-points. Notably, the abundance of important salivary proteins, such as histatin 1, decrease with increasing of the AEP formation, while other essential proteins such as statherin showed constant relative abundance in all time-points. In summary, this is the first study that investigates the dynamic process to the AEP formation by using proteomic approaches. Our data demonstrated that there are significant qualitative and quantitative proteome changes during the AEP formation, which in turn will likely impact the development of oral biofilms.

Proteome and peptidome of human acquired enamel pellicle on deciduous teeth.

Understanding the composition and structure of the acquired enamel pellicle (AEP) has been a major goal in oral biology. Our lab has conducted studies on the composition of AEP formed on permanent enamel. The exhaustive exploration has provided a comprehensive identification of more than 100 proteins from AEP formed on permanent enamel. The AEP formed on deciduous enamel has not been subjected to the same biochemical characterization scrutiny as that of permanent enamel, despite the fact that deciduous enamel is structurally different from permanent enamel. We hypothesized that the AEP proteome and peptidome formed on deciduous enamel may also be composed of unique proteins, some of which may not be common with AEP of permanent enamel explored previously. Pellicle material was collected from 10 children (aged 18-54 months) and subjected to mass spectrometry analysis. A total of 76 pellicle proteins were identified from the deciduous pellicle proteome. In addition, 38 natural occurring AEP peptides were identified from 10 proteins, suggesting that primary AEP proteome/peptidome presents a unique proteome composition. This is the first study to provide a comprehensive investigation of in vivo AEP formed on deciduous enamel.

Emergency department triage of low acuity patients to a Federally Qualified Health Center.

Many emergency departments (ED) are experiencing ever increasing volumes as they serve as a safety net for patients without established access to primary care. Impending physician shortages, our aging population, and recent changes in national healthcare policy are expected to further exacerbate this situation and worsen ED overcrowding. These conditions could result in a dilution of ED resources and significantly impact the ability of emergency personnel to provide quality care for patients with serious illnesses. Previous studies have demonstrated that low acuity patients without emergencies can be safely and legally identified in triage and can be sent away from the ED for further outpatient treatment and evaluation. However, without a specific designated clinic follow up, these patients often fail to get the appropriate care required. In this study, we couple the ED medical screening exam process with a timely medical referral system to a local Federally Qualified Healthcare Clinic (FQHC). These referred patients were monitored for subsequent success in satisfaction with their primary care needs and their rate of recidivism to the ED. Most of the non-emergent patients who were judged to be appropriate to refer to the FQHC were satisfied with their medical screening process (89%) and most elected to attend the same day clinic appointment at the FQHC (85%). Only 17% of these patients who were referred out of our ED returned to be seen in our ED within the three-month interval. We concluded that referring low acuity patients out of the emergency department to a primary care clinic setting provided an opportunity for these patients to establish a medical home for future access to non-emergent health care.

Standards for Environmental Measurement Using GIS: Toward a Protocol for Protocols.

BACKGROUND: Interdisciplinary research regarding how the built environment influences physical activity has recently increased. Many research projects conducted jointly by public health and environmental design professionals are using geographic information systems (GIS) to objectively measure the built environment. Numerous methodological issues remain, however, and environmental measurements have not been well documented with accepted, common definitions of valid, reliable variables. METHODS: This paper proposes how to create and document standardized definitions for measures of environmental variables using GIS with the ultimate goal of developing reliable, valid measures. Inherent problems with software and data that hamper environmental measurement can be offset by protocols combining clear conceptual bases with detailed measurement instructions. RESULTS: Examples demonstrate how protocols can more clearly translate concepts into specific measurement. CONCLUSIONS: This paper provides a model for developing protocols to allow high quality comparative research on relationships between the environment and physical activity and other outcomes of public health interest.