McKing Consulting (United States)

Misclassification of correlated binary responses may occur in clinical and epidemiological studies, resulting in biased and/or inefficient parameter estimation. We extend existing generalized estimating equation (GEE) approaches to allow for differential misclassification via two sets of estimating equations for the analysis of error-prone correlated binary outcomes when internal validation data are available. One set of estimating equations uses logistic regression to model the misclassification process with the internal validation data, using subject characteristics to estimate the differential sensitivities and specificities of the error-prone response in relation to the gold standard. The second set of estimating equations models the mismeasured binary response by leveraging the subject-specific estimates of sensitivity and specificity. The subject-specific covariates need not be identical in the two sets of estimating equations. We present analysis of longitudinal assessments of bacterial vaginosis from the HIV Epidemiology Research Study (HERS), compare the proposed population-average approach based on GEE with a subject-specific one based on a full-likelihood mixed-effects analysis, and discuss the differing parameter interpretations. We also present results from simulated data with a misclassified binary outcome analyzed with this GEE approach.

Abstract Coexisting plants in drylands with different rooting depths can exploit different spatial water sources to maintain productivity. The sequence of water potential thresholds for key physiological events during dehydration strongly influences overall plant function. However, how rooting depth coordinates with this water potential sequence remains poorly understood. Here, we measured leaf structural, hydraulic, and stomatal traits of eight coexisting desert woody species with rooting depths ranging from 69 to 337 cm. Rooting depth was positively related to hydraulic efficiency, turgor loss point, leaf embolism resistance, and stomatal closure point, but negatively related to non-structural carbohydrates and water use efficiency. Positive correlations between rooting depth and hydraulic/stomatal safety margins suggested that deep-rooted species had a conservative water potential sequence, i.e., preemptively closing stomata to prevent substantial embolism occurrence. Conversely, shallow-rooted species displayed a risky water potential sequence but adopted compensatory strategies, including low water demand, strong embolism repair capacity, and high carbon allocation to sapwood area relative to leaf area. Together, our results suggest that severe water limitation imposes strong selective pressure, resulting in tight coordination among rooting depth, stomatal regulation, water use, embolism resistance and repair, and structural construction, which is critical for species coexistence in desert ecosystems.

IntroductionThis study examines how an early-life small-quantity lipid-based nutrient supplement (LNS) interacts with the home environment to influence Ghanaian children's social-emotional functioning at preschool age.MethodIn a randomized controlled trial, 1,320 Ghanaian women received either daily LNS, multiple micronutrients (MMN) or iron and folic acid (IFA) during pregnancy through 6 months postpartum. Infants in the LNS group received the daily supplement from 6 to 18 months. The IFA and MMN groups were combined to be the control group. At 4–6 years (n = 966), we assessed children's home environments (caregiver responsivity, negative behavior acceptance, physical environment, learning materials, academic stimulation) and their social-emotional strengths and difficulties.ResultsBoth LNS and higher quality home environments—particularly caregiver responsivity and negative behavior acceptance—predicted children having fewer social-emotional difficulties. LNS supplementation moderated relations between the home environment and children's hyperactivity/inattention and total difficulties. Living in a safer physical environment was related to fewer hyperactivity/inattention problems and total difficulties only for children who received LNS. Less academic stimulation was related to more hyperactivity/inattention only for children in the control group.ConclusionEarly-life LNS supplementation and supportive home environments reduce social-emotional difficulties in Ghanaian children. Nutritional interventions are most effective in the context of safe, stimulating households, demonstrating that integrated interventions support children's wellbeing in low- and middle-income countries.Clinical trial registrationclinicaltrials.gov; identifier: NCT00970866.

BackgroundSchool food environments may play an important role in shaping children's dietary habits, health, and nutrition.ObjectivesThis study aimed to evaluate associations between the school food environment and nutrition among in-school adolescents in Ghana.MethodsData were collected in Ghana in 2022 in a national nutrition and health survey of adolescents attending junior (JHS) and senior high schools (SHS). Foods observed on campus or reported in the dietary recall were aggregated, a composite Adolescent Dietary Diversity Score (ADDS) was derived, and the proportion achieving minimum dietary diversity was estimated. Multi-level regression models were used to assess associations between a ranked school food environment score (FES) and nutrition outcomes.ResultsThe number of food groups served or available for purchase was 6.2 in JHS and 8.1 in SHS (P-value < .0001). The mean (95% CI) FES was 10.9 (10.1-11.7) at JHS and 14.3 (13.6-14.9) at SHS. ADDS ranged from 4.1 to 4.8 across strata. Higher FES was positively associated with ADDS and minimum dietary diversity among SHS students and negatively associated with anemia in girls and boys. Girls from high FES schools had 24% lower odds of anemia (OR = 0.76; 95% CI = 0.63-0.93) while boys had 46% lower odds (OR = 0.54; 95% CI = 0.34-0.84) compared to students in low FES schools.ConclusionsHigher FES was associated with greater dietary diversity among SHS students and lower odds of anemia in girls and boys, suggesting that the school food environment may play a role in determining nutrition outcomes.

Introduction: The 2018 Physical Activity Guidelines Advisory Committee Scientific Report called for investigating whether the established health benefits of meeting physical activity guidelines (PAG) differ by sociodemographic factors. Guidelines for adults recommend engaging in muscle-strengthening activities (MSAs; ≥2 days per week) and moderate-to-vigorous aerobic physical activity (MVPA; ≥150 minutes per week at moderate intensity, ≥75 minutes per week at vigorous intensity, or an equivalent combination). Objective: To examine associations between meeting MVPA and MSA guidelines (combined PAG) in leisure time and all-cause and heart disease mortality across sociodemographic factors. Methods: We used nationally representative data on 567,483 adults from the 1998-2018 US National Health Interview Survey (NHIS) and 2019 public-use linked mortality files from the National Death Index. Median follow-up was 9.5 years (range=1-21.8 years). We classified participants into categories (met combined PAG, met MVPA only, met MSA only, met neither) based on reported leisure-time physical activity. We used Cox regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between meeting the combined PAG vs. meeting neither guideline and all-cause and heart disease mortality, overall and stratified by sex (women, men), race and ethnicity (six groups), or education (four levels). Models were adjusted for sociodemographic and health factors. We conducted pairwise comparisons (adjusted for multiple comparisons) to determine if associations differed across sociodemographic factors. Results: Compared to meeting neither PAG, meeting the combined PAG was associated with a reduced mortality risk between 14-36% for all-cause mortality and 25-52% for heart disease mortality across sociodemographic groups. Reductions in mortality risk were larger for some groups compared with others. For example, reduction in all-cause mortality was larger for non-Hispanic White compared with Hispanic or Latino adults (HR=0.66 [95% CI: 0.64-0.69] vs. 0.86 [0.75-0.99]; pairwise p &lt;0.001) and for people with more vs. less education (college or more=0.64 [0.60-0.69] vs. less than high school=0.75 [0.69-0.82]; p &lt;0.001). Reduction in heart disease mortality was larger for women compared with men (0.54 [0.48-0.62] vs. 0.66 [0.60-0.73]; p &lt;0.001). Conclusions: Meeting the guidelines for MVPA and MSA generally provides a substantial reduction in risk of all-cause and heart disease mortality. There may be differences in the magnitude of benefit physical activity provides for health across sociodemographic groups. The reasons for these differences are unclear. Identifying factors contributing to these differences would further address research gaps identified in the 2018 Physical Activity Guidelines Advisory Committee Scientific Report.

Early in the COVID-19 pandemic, access to and participation in leisure-time physical activity was plausibly different across sociodemographic strata of the US population. Currently, the Behavioral Risk Factor Surveillance System (BRFSS) is the only national public health surveillance system with a consistent measure of physical activity pre- and intra-pandemic. PURPOSE: To assess changes in prevalence of leisure-time physical inactivity across sociodemographic groups in the US during 2020 versus 2018. METHODS: National data from BRFSS among 838,017 US adults aged ≥18 years were analyzed. Participants who reported "no" when asked, "during the past month, other than your regular job, did you participate in any physical activities or exercises such as running, calisthenics, golf, gardening, or walking for exercise?" were classified as physically inactive. Prevalence differences with 95% confidence intervals [CI] of leisure-time physical inactivity during 2020 versus 2018 were calculated overall and by sociodemographic characteristics (sex, age, urbanicity, race/ethnicity, education, and income). Sex-specific prevalence differences were also calculated by sociodemographic group. CIs not containing zero were deemed statistically significant. RESULTS: Prevalence of inactivity among US adults overall decreased 0.7 percentage points (PP) (95% CI: -1.2, -0.3), from 24.5% in 2018 to 23.8% in 2020. Decreases were observed among persons aged 45-64 years (-1.5PP, [95% CI: -2.3, -0.7]) and ≥ 65 years (-1.3PP, [-2.1, -0. 4]), women (-1.2PP, [-1.8, -0.6]), non-Hispanic White persons (-1.5PP, [-2.0, -1.1]), and persons living in rural counties (-2.6PP, [-3.8, -1.4]) and in urban counties, to a smaller extent (-0.6PP, [-1.0, -0.1]). No significant decreases were observed for racial and ethnic minority groups overall. Notable sex-specific decreases occurred among rural-dwelling women (-3.1 PP, [-4.7, -1.5]), rural-dwelling men (-2.1 PP, [-3.8, -0.3]), and non-Hispanic White women (-2.1PP, [-2.7, -1.5]). CONCLUSIONS: Self-reported leisure-time physical inactivity modestly decreased among specific US subpopulations from 2018 to 2020. This study highlights a need to better understand drivers of leisure-time physical activity across populations, particularly during periods of social disruption.

Abstract The volume‐fraction changes of CO2 and H2O after adding different proportions of H2 to the hydrogen‐rich blast furnace were simulated by thermodynamic calculations to evaluate the effects of H2 on coke gasification in a blast furnace. Thermodynamic calculations indicated that the H2O content in the mixed gas gradually increased with higher H2 content. The coke gasification kinetics effective diffusion coefficient De and interfacial reaction rate constant k+ of the coke gasification reaction improved with higher H2 content. In addition, the reactivity of cokes enhanced and the coke strength after reaction decreased with higher H2 content. Mercury porosimeter experiments demonstrated that the coke gasification reaction mainly occurred on the surface.

Motor vehicle traffic is commonly cited as a barrier to walking, but national level perceptions of traffic characteristics that negatively influence walking and potential traffic mitigation strategies remain unclear. The objectives of this study were to describe perceptions of (1) traffic characteristics that make walking unsafe in the United States and (2) potential mitigation strategies to address these concerns among those who report traffic as a barrier to walking. Data were from FallStyles, a nationwide internet panel survey conducted in October 2019 (n = 3,284 adults). Respondents reported if traffic makes walking unsafe where they live; those who answered yes were then asked about traffic characteristics that make walking unsafe (number of vehicles, speed of vehicles, distracted or impaired driving, types of vehicles, and other reasons) and potential mitigation strategies (new or improved sidewalks, crosswalks, pedestrian signals, street lighting, things that slow vehicles down, separating the sidewalk from the road, fewer vehicle lanes, and other). Prevalence of responses was assessed overall and by select sociodemographic and geographic characteristics, and by walking status. Nearly 25% of US adults reported that traffic is a barrier to walking where they live. Of these, 79% selected vehicle speed as a contributing traffic characteristic, and 57% indicated new or improved sidewalks as a potential mitigation strategy. These top responses were shared across all sociodemographic, geographic, and walking behavior subgroups. Speed reduction efforts and built environment enhancements such as sidewalks may alleviate pedestrian safety concerns. Promotion campaigns may be needed to bring awareness to such changes.