C-reactive protein (CRP) in high altitude Bolivian peri-urban adolescents varies by adiposity, current illness, height, socioeconomic status, sex, and menarcheal status: The potential benefits and costs of adipose reserves in arduous environments.

OBJECTIVES: In non-industrialized and low-income populations, adipose stores can serve as a valuable buffer against harsh conditions such as seasonal food scarcity. However, these reserves may incur costs due to adipocytes' production of pro-inflammatory cytokines; inflammation is associated with increased risk for cardiometabolic diseases later in life. Life history theory posits that, especially in populations with high juvenile mortality, higher adiposity may nonetheless be advantageous if its benefits in early life outweigh its later costs. Relatively little is known about adolescents' C-reactive protein concentration (CRP; an inflammation biomarker) in such environments. We investigated CRP and its associations with several hypothesized predictors in adolescents in an economically diverse peri-urban Andean community. METHODS: We measured CRP in dried blood spots and collected data on anthropometrics, illnesses, socioeconomic status (SES), and menarcheal status in 59 female and 40 male adolescents ("Alteños", 11.0-14.9 years old) with normal vital signs in El Alto, Bolivia (~4150 m amsl). We used Cole's LMS method to standardize all anthropometrics for sex and age, and principal components analysis to construct a "fat-factor" variable loading on these standardized z-scores. We used multiple linear regression to assess the influence of fat-factor and other likely predictors on CRP rank. RESULTS: Compared to a national Bolivian growth reference, Alteños were, on average, shorter and leaner; only 6% were classified as overweight and none were obese. Pre-menarche females were on average leaner than post-menarche females. The best-fitting model explained 24% of the variance in CRP rank. Significant predictors were fat-factor, SES, current illness for males and pre-menarche females, and z-height for females. CONCLUSIONS: Our results are consistent with a tradeoff between investments in growth versus immune functioning, as might be expected in an environment with limited resources and high pathogen exposure (e.g., soil-transmitted helminths, poor sanitation). Thinner Alteños appear to maintain a minimum CRP concentration independent of fat-factor, while fatter (or less-thin) Alteños' CRP rises with fat-factor. Female Alteños appear to be trading off investment in immune response for investment in growth and maturation. Alteños' high rate of stunting and absence of obesity suggests chronic, presumably multifactorial, stress. Adipose stores likely buffer against some of these stressors and, in an environment such as this-in which many lack sufficient nutritious foods, potable water, adequate sewage, and health care-may confer a net lifetime benefit.

OBJETIVOS: En poblaciones no industrializadas y de bajos ingresos, las reservas adiposas pueden servir como un valioso amortiguador frente a condiciones duras como la escasez estacional de alimentos. Sin embargo, estas reservas pueden tener un coste debido a la producción de citoquinas proinflamatorias por parte de los adipocitos; la inflamación se asocia a un mayor riesgo de enfermedades cardiometabólicas en etapas posteriores de la vida. La teoría de la historia vital postula que, especialmente en poblaciones con una elevada mortalidad juvenil, una mayor adiposidad puede ser ventajosa si sus beneficios en los primeros años de vida compensan sus costes posteriores. Se sabe relativamente poco sobre la concentración de proteína C reactiva (PCR; un biomarcador de inflamación) de los adolescentes. Investigamos la PCR y sus asociaciones con varios predictores hipotéticos en adolescentes de una comunidad andina periurbana económicamente diversa. MÉTODOS: Se midió la PCR en muestras de sangre seca y se recogieron datos sobre antropometría, enfermedades, nivel socioeconómico (NSE) y menarquia en 59 mujeres y 40 varones adolescentes («alteños¼, 11,0­14,9 años de edad) con signos vitales normales en El Alto, Bolivia (~4150m amsl). Usamos el método LMS de Cole para estandarizar todos los parámetros antropométricos para sexo y edad, y análisis de componentes principales para construir una variable «factor de grasa¼ cargada en estos puntajes z­estandarizados. Se utilizó la regresión lineal múltiple para evaluar la influencia del factor grasa y otros posibles predictores en el rango de la PCR. RESULTADOS: En comparación con una referencia nacional boliviana de crecimiento, los alteños eran, en promedio, más bajos y más delgados; sólo el 6% estaban clasificados con sobrepeso y ninguno era obeso. Las chicas premenárquicos eran, en promedio, más delgados que las chicas postmenárquicos. El modelo de regresión que mejor se ajustaba explicaba el 24% de la varianza en el rango de PCR. Observamos una nueva asociación entre la adiposidad y la PCR. Cuando el factor adiposidad es >0, el rango de la PCR aumenta linealmente con el factor adiposidad. Cuando el factor adiposidad es <0, la PCR no varía con el factor adiposidad. Estos patrones sugieren que los Alteños más delgados mantienen una concentración mínima de PCR independiente del factor adiposidad, mientras que la PCR de los Alteños más gordos (menos delgados) aumenta con el factor adiposidad. Además, existe una mayor variación en el rango de la PCR en los adolescentes más delgados que en los más gordos. El autoinforme de una enfermedad actual en niños y niñas premenárquicas se asoció con una PCR significativamente más alta. La ausencia de una asociación significativa entre la enfermedad actual y la PCR en las chicas postmenárquicas puede reflejar confusión por cambios en la PCR durante el ciclo menstrual. Manteniendo constantes todos los demás factores predictivos, la PCR aumentó con el incremento del nivel socioeconómico. En las niñas, el aumento de la estatura se asoció a una disminución de la PCR, lo que sugiere que las niñas favorecen la inversión en crecimiento y maduración frente a la inversión en respuestas inmunitarias inflamatorias a corto plazo. En los chicos, no se observó una relación significativa entre la estatura y la PCR. La baja estatura y la delgadez de estos adolescentes sugieren que pueden estar invirtiendo en defensas humorales a más largo plazo (por ejemplo, anticuerpos contra helmintos), pero esta hipótesis requiere más estudios. CONCLUSIONES: La alta tasa de retraso en el crecimiento y la ausencia de obesidad de los alteños sugieren un estrés crónico, presumiblemente multifactorial. Muchas familias carecen de alimentos nutritivos suficientes, agua potable, alcantarillado adecuado y atención sanitaria. Es probable que las reservas adiposas amortigüen algunos de estos factores de estrés y confieran un beneficio neto a lo largo de la vida (la reducción de la mortalidad juvenil puede compensar cualquier aumento del riesgo de enfermedades cardiometabólicas en etapas posteriores de la vida). Sin embargo, estas compensaciones tienen un coste para los individuos y las sociedades. Reducir los riesgos de patógenos y mejorar la capacidad de los habitantes del altiplano para acceder sistemáticamente a agua limpia y a alimentos sanos suficientes y asequibles probablemente reportaría beneficios para la salud a lo largo de toda la vida.

Well-being in healthy Icelandic women varies with extreme seasonality in ambient light.

Seasonal variation in photoperiod may affect psychosocial and physical well-being in healthy persons. We tested this hypothesis in healthy pre-menopausal women, without a history of mood disorders, living year-round in Reykjavik, Iceland (64.1°N). Participants reported daily self-assessments of well-being throughout a complete ovulatory menstrual cycle in summer and/or winter (70% participated in both seasons). Scores for mood, cognitive acuity, social support, physical health and a composite of these four indicators were each significantly higher in summer than in winter (linear mixed effects models: p < .001 for each model); tiredness did not differ by season. The effect of season was not significantly changed by inclusion of body mass index and/or age as covariates. Some prior studies have been hampered by sparse time sampling, inattention to covariates and/or relying on recalled data. This is to our knowledge the first investigation to test the study hypothesis with daily real-time data spanning complete ovulatory menstrual cycles in each of two seasons. This dense sampling has revealed modest seasonal variation in well-being in healthy women. Daylength (sunlight exposure) is likely a major, but not necessarily sole, factor in these seasonal differences in well-being; temperature is likely less important given Iceland's relatively moderate (for its high latitude) seasonal temperature swings.

Assessment of App-Based Versus Conventional Survey Modalities for Reproductive Health Research in India, South Africa, and the United States: Comparative Cross-Sectional Study.

BACKGROUND: There is a widely acknowledged global need for more research on reproductive health (including contraception, menstrual health, sexuality, and maternal morbidities) and its impact on overall well-being. However, several factors-notably, high costs, considerable effort, and the sensitivity of these topics-impede the collection of the necessary data, especially in less accessible and lower-income populations. The burgeoning ownership of smartphones and growing use of menstrual tracking apps (MTAs) may present an opportunity to conduct reproductive health research with fewer impediments than those associated with conventional survey methods. OBJECTIVE: The main objective was to ascertain the feasibility, potential usefulness, and limitations of conducting reproductive health research using a mainstream MTA. METHODS: In each of the 3 countries, we evaluated questionnaire responses from (1) current users of an MTA (Clue) and (2) participants surveyed using conventional survey modalities (in-person interviews, SMS text messaging, and web-based questionnaires). We compared these responses with published data collected from large nationally representative benchmark samples (the United States Census and the Demographic and Health Surveys for South Africa and India). RESULTS: Given a sufficiently large user base, app-distributed surveys were able to quickly capture large samples on par with other methods and at low cost, with the additional advantage of being able to deploy remotely and simultaneously across countries. In each country, neither the app nor the conventional modality sample emerged as a consistently closer match to the distributions of the demographic attributes and the patterns of contraceptive use reported for the respective benchmark sample. Despite efforts to obtain representative samples, the conventional modality samples sometimes over- and other times underrepresented some subgroups (eg, underrepresentation of married persons in the United States and overrepresentation of rural residents in India). In all 3 countries, app users were younger, more educated, more likely to be urban residents, and more likely to use nonhormonal rather than hormonal contraceptive methods compared with the respective national benchmark. App users, compared with the conventional modality samples, consistently reported being more comfortable discussing their menstrual periods with other persons (eg, family, friends, and health care providers), suggesting that MTA users may be more likely to respond truthfully to questions on sensitive or taboo health topics. The app samples' consistency across countries regarding users' demographic profiles, contraceptive choices, and personal attitudes toward menstruation supports the validity of making cross-country comparisons of survey findings for a given app's users. CONCLUSIONS: MTAs such as Clue can provide a quick, scalable, and cost-effective method for collecting health data, including on sensitive topics, across a wide variety of settings and countries. With expanding global access to technology and the increasing use of these tools, consumer MTAs can be a viable survey modality to strengthen reproductive health research.

Breathing zone pollutant levels are associated with asthma exacerbations in high-risk children.

Background: Indoor and outdoor air pollution levels are associated with poor asthma outcomes in children. However, few studies have evaluated whether breathing zone pollutant levels associate with asthma outcomes. Objective: Determine breathing zone exposure levels of NO 2 , O 3 , total PM 10 and PM 10 constituents among children with exacerbation-prone asthma, and examine correspondence with in-home and community measurements and associations with outcomes. Methods: We assessed children's personal breathing zone exposures using wearable monitors. Personal exposures were compared to in-home and community measurements and tested for association with lung function, asthma control, and asthma exacerbations. Results: 81 children completed 219 monitoring sessions. Correlations between personal and community levels of PM 10 , NO 2 , and O 3 were poor, whereas personal PM 10 and NO 2 levels correlated with in-home measurements. However, in-home monitoring underdetected brown carbon (Personal:79%, Home:36.8%) and ETS (Personal:83.7%, Home:4.1%) personal exposures, and detected black carbon in participants without these personal exposures (Personal: 26.5%, Home: 96%). Personal exposures were not associated with lung function or asthma control. Children experiencing an asthma exacerbation within 60 days of personal exposure monitoring had 1.98, 2.21 and 2.04 times higher brown carbon (p<0.001), ETS (p=0.007), and endotoxin (p=0.012), respectively. These outcomes were not associated with community or in-home exposure levels. Conclusions: Monitoring pollutant levels in the breathing zone is essential to understand how exposures influence asthma outcomes, as agreement between personal and in-home monitors is limited. Inhaled exposure to PM 10 constituents modifies asthma exacerbation risk, suggesting efforts to limit these exposures among high-risk children may decrease their asthma burden. CLINICAL IMPLICATIONS: In-home and community monitoring of environmental pollutants may underestimate personal exposures. Levels of inhaled exposure to PM 10 constituents appear to strongly influence asthma exacerbation risk. Therefore, efforts should be made to mitigate these exposures. CAPSULE SUMMARY: Leveraging wearable, breathing-zone monitors, we show exposures to inhaled pollutants are poorly proxied by in-home and community monitors, among children with exacerbation-prone asthma. Inhaled exposure to multiple PM 10 constituents is associated with asthma exacerbation risk.

More than blood: app-tracking reveals variability in heavy menstrual bleeding construct.

BACKGROUND: Heavy menstrual bleeding (HMB) is associated with impaired quality of life and may signal serious health problems. Unresolved challenges in measuring menstrual bleeding and identifying HMB have hampered research and clinical care. Self-reported bleeding histories are commonly used but these may be influenced by recall bias, personal beliefs regarding "normal" flow volume, and the experience of other physical symptoms or disruptions to daily life. The potential usefulness of menstrual-tracking mobile applications, which allow real-time user-entered data recording, for assessing HMB has not been studied. We evaluated recall bias in reported period duration, the relationship of tracked period duration and daily flow volume to subsequently reported period heaviness, variation in quality of life associated with increasing period heaviness, and the advantages and limitations of using app-tracked data for clinical and research purposes. METHODS: An online questionnaire was distributed to current users of Clue, a commercially available menstrual health tracking app, asking them to characterize their last period. We compared responses to the user's corresponding Clue app-tracked data. The study sample comprised 6546 U.S.-based users (aged 18-45 years). RESULTS: Increasing reported heaviness was associated with increasing app-tracked period length and days of heavy flow, impaired quality-of-life (especially body pain severity), and disrupted activities. Of those reporting having had a heavy/very heavy period, ~ 18% had not tracked any heavy flow, but their period length and quality-of-life indicators were similar to those who had tracked heavy flow. Sexual/romantic activities were the most affected across all flow volumes. Compared to app-tracked data, 44% recalled their exact period length; 83% recalled within ± 1 day. Overestimation was more common than underestimation. However, those with longer app-tracked periods were more likely to underestimate period length by ≥ 2 days, a pattern which could contribute to under-diagnosis of HMB. CONCLUSION: Period heaviness is a complex construct that encapsulates flow volume and, for many, several other bleeding-associated experiences (period length, bodily impairments, disruptions of daily activities). Even very precise flow volume assessments cannot capture the multi-faceted nature of HMB as experienced by the individual. Real-time app-tracking facilitates quick daily recording of several aspects of bleeding-associated experiences. This more reliable and detailed characterization of bleeding patterns and experiences can potentially increase understanding of menstrual bleeding variability and, if needed, help to guide treatment.

Socioeconomic impacts on Andean adolescents' growth: Variation between households, between communities and over time.

Background/Objectives: We evaluated potential socioeconomic contributors to variation in Andean adolescents' growth between households within a peri-urban community undergoing rapid demographic and economic change, between different community types (rural, peri-urban, urban) and over time. Because growth monitoring is widely used for assessing community needs and progress, we compared the prevalences of stunting, underweight, and overweight estimated by three different growth references. Methods: Anthropometrics of 101 El Alto, Bolivia, adolescents (Alteños), 11.0-14.9 years old in 2003, were compared between households (economic status assessed by parental occupations); to one urban and two rural samples collected in 1983/1998/1977, respectively; and to the WHO growth reference, a representative sample of Bolivian children (MESA), and a region-wide sample of high-altitude Peruvian children (Puno). Results: Female Alteños' growth was positively associated with household and maternal income indices. Alteños' height averaged ∼0.8SD/∼0.6SD/∼2SDs greater than adolescents' height in urban and rural communities measured in 1983/1998/1977, respectively. Overweight prevalence was comparable to the WHO, and lower than MESA and Puno, references. Stunting was 8.5/2.5/0.5 times WHO/MESA/Puno samples, respectively. Conclusions/Implications: Both peri-urban conditions and temporal trends contributed to gains in Alteños' growth. Rural out-migration can alleviate migrants' poverty, partly because of more diverse economic options in urbanized communities, especially for women. Nonetheless, Alteños averaged below WHO and MESA height and weight medians. Evolved biological adaptations to environmental challenges, and the consequent variability in growth trajectories, favor using multiple growth references. Growth monitoring should be informed by community- and household-level studies to detect and understand local factors causing or alleviating health disparities.

Reducing household air pollution exposure to improve early child growth and development; a randomized control trial protocol for the "Poriborton-Extension: The CHANge trial".

BACKGROUND: Globally, household air pollution (HAP) is a leading environmental cause of morbidity and mortality. Our trial aims to assess the impact of liquefied petroleum gas (LPG) for cooking to reduce household air pollution exposure on child health outcomes, compared to usual cooking practices in Bangladesh. The primary aim is to evaluate if reduced exposure to HAP through the provision of LPG for cooking from early gestation through to age 2 improves child anthropometry, health, and neuro-cognitive developmental outcomes, compared to children exposed to emissions from usual practice. METHODS: Two-arm parallel cluster randomized controlled trial (cCRT). We will extend the intervention and follow-up of our existing "Poriborton" trial. In a subset of the original surviving participants, we will supply LPG cylinders and LPG stoves (intervention) compared to usual cooking practices and extend the follow-up to 24 months of age. The expected final sample size, for both (intervention and control) is 1854 children with follow-up to 2 years of age available for analysis. DISCUSSION: This trial will answer important research gaps related to HAP and child health and neuro-cognitive developmental outcomes. This evidence will help to understand the impact of a HAP intervention on child health to inform policies for the adoption of clean fuel in Bangladesh and other similar settings. TRIAL REGISTRATION: The Poriborton: Change trial: Household Air Pollution and Perinatal and early Neonatal mortality is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12618001214224, original trial registered on 19th July 2018, extension approved on 23rd June 2021. www.anzctr.org.au .

Protocol for a cluster randomised controlled trial of LPG cookstoves compared to usual cooking practices to reduce perinatal mortality and morbidity in rural Bangladesh called Poriborton: the CHANge trial.

BACKGROUND: Household air pollution is a leading health risk for global morbidity and mortality and a major health risk in South Asia. However, there are no prospective investigations of the impact of household air pollution on perinatal morbidity and mortality. Our trial aims to assess the impact of liquefied petroleum gas (LPG) for cooking to reduce household air pollution exposure on perinatal morbidity and mortality compared to usual cooking practices in Bangladesh. HYPOTHESIS: In a community-based cluster randomised controlled trial of pregnant women cooking with LPG throughout pregnancy, perinatal mortality will be reduced by 35% compared with usual cooking practices in a rural community in Bangladesh. METHODS: A two-arm community-based cluster randomised controlled trial will be conducted in the Sherpur district, Bangladesh. In the intervention arm, pregnant women receive an LPG cookstove and LPG in cylinders supplied throughout pregnancy until birth. In the control or usual practice arm, pregnant women continue their usual cooking practices, predominately traditional stoves with biomass fuel. Eligible women are pregnant women with a gestational age of 40-120 days, aged between 15 and 49 years, and permanent residents of the study area. The primary outcome is the difference in perinatal mortality between the LPG arm and the usual cooking arm. Secondary outcomes include (i) preterm birth and low birth weight, (ii) personal level exposure to household air pollution, (iii) satisfaction and acceptability of the LPG stove and stove use, and (iv) cost-effectiveness and cost-utility in reducing perinatal morbidity and mortality. We follow up all women and infants to 45 days after the birth. Personal exposure to household air pollution is assessed at three-time points in a sub-sample of the study population using the MicroPEM™. The total required sample size is 4944 pregnant women. DISCUSSION: This trial will produce evidence of the effectiveness of reduced exposure to household air pollution through LPG cooking to reduce perinatal morbidity and mortality compared to usual cooking practices. This evidence will inform policies for the adoption of clean fuel in Bangladesh and other similar settings. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12618001214224 . Prospectively registered on 19 July 2019.

Pregnant Women's Exposure to Household Air Pollution in Rural Bangladesh: A Feasibility Study for Poriborton: The CHANge Trial.

The use of liquefied petroleum gas (LPG) for cooking is a strategy to reduce household air pollution (HAP) exposure and improve health. We conducted this feasibility study to evaluate personal exposure measurement methods to representatively assess reductions in HAP exposure. We enrolled 30 pregnant women to wear a MicroPEM for 24 h to assess their HAP exposure when cooking with a traditional stove (baseline) and with an LPG stove (intervention). The women wore the MicroPEM an average of 77% and 69% of the time during the baseline and intervention phases, respectively. Mean gravimetric PM2.5 mass and black carbon concentrations were comparable during baseline and intervention. Temporal analysis of the MicroPEM nephelometer data identified high PM2.5 concentrations in the afternoon, late evening, and overnight during the intervention phase. Likely seasonal sources present during the intervention phase were emissions from brick kiln and rice parboiling facilities, and evening kerosene lamp and mosquito coil use. Mean background adjusted PM2.5 concentrations during cooking were lower during intervention at 71 µg/m3, versus 105 µg/m3 during baseline. Representative real-time personal PM2.5 concentration measurements supplemented with ambient PM2.5 measures and surveys will be a valuable tool to disentangle external sources of PM2.5, other indoor HAP sources, and fuel-sparing behaviors when assessing the HAP reduction due to intervention with LPG stoves.

Thermal Degradants Identified from the Vaping of Vitamin E Acetate.

Studies have suggested that vitamin E acetate (VEA), when used in an electronic vaping device, undergoes thermal degradation and is considered one of the main contributors in e-cigarette or vaping product use-associated lung injury (EVALI). Using a Borgwaldt 5.1 linear smoker, a SVS250 Electronic Vaporizer and two types of tank systems, VEA was analyzed for degradation products produced via the Cooperation Centre for Scientific Research Relative to Tobacco method 81 when the filter containing vaporized VEA was extracted using acetonitrile. Two of the major products identified were 2,3,5,6-tetramethyl-1,4-benzoquinone and 2,6,10,14-tetramethyl-1-pentadecene, which were confirmed using analytical standards and gas chromatography-high-resolution mass spectrometry (GC-HRMS). Additional synthesis of 4-acetoxy-2,3,5,6-tetramethyl-2,4-cyclohexadienone and subsequent characterization using nuclear magnetic resonance and GC-HRMS suggested that this is not one of the products produced. Identification of these degradants will allow future studies to quantify and examine the degradants in vivo and in vitro as biomarkers for exposure and toxicity assessment.

Children's Particulate Matter Exposure Characterization as Part of the New Hampshire Birth Cohort Study.

As part of the New Hampshire Birth Cohort Study, children 3 to 5 years of age participated in a personal PM2.5 exposure study. This paper characterizes the personal PM2.5 exposure and protocol compliance measured with a wearable sensor. The MicroPEM™ collected personal continuous and integrated measures of PM2.5 exposure and compliance data on 272 children. PM2.5, black carbon (BC), and brown carbon tobacco smoke (BrC-ETS) exposure was measured from the filters. We performed a multivariate analysis of woodstove presence and other factors that influenced PM2.5, BC, and BrC exposures. We collected valid exposure data from 258 of the 272 participants (95%). Children wore the MicroPEM for an average of 46% of the 72-h period, and over 80% for a 2-day, 1-night period (with sleep hours counted as non-compliance for this study). Elevated PM2.5 exposures occurred in the morning, evening, and overnight. Median PM2.5, BC, and BrC-ETS concentrations were 8.1 µg/m3, 3.6 µg/m3, and 2.4 µg/m3. The combined BC and BrC-ETS mass comprised 72% of the PM2.5. Woodstove presence, hours used per day, and the primary heating source were associated with the children's PM2.5 exposure and air filters were associated with reduced PM2.5 concentrations. Our findings suggest that woodstove smoke contributed significantly to this cohort's PM2.5 exposure. The high sample validity and compliance rate demonstrated that the MicroPEM can be worn by young children in epidemiologic studies to measure their PM2.5 exposure, inform interventions to reduce the exposures, and improve children's health.

Recognizing normal reproductive biology: A comparative analysis of variability in menstrual cycle biomarkers in German and Bolivian women.

The idealized "normal" menstrual cycle typically comprises a coordinated ebb and flow of hormones over a 28-day span with ovulation invariably shown at the midpoint. It's a pretty picture-but rare. Systematic studies have debunked the myth that cycles occur regularly about every 28 days. However, assumptions persist regarding the extent and normalcy of variation in other cycle biomarkers. The processes of judging which phenotypic variants are "normal" is context dependent. In everyday life, normal is that which is most commonly seen. In biomedicine normal is often defined as an arbitrarily bounded portion of the phenotype's distribution about its statistical mean. Standards thus defined in one population are problematic when applied to other populations; population specific standards may also be suspect. Rather, recognizing normal female reproductive biology in diverse human populations requires specific knowledge of proximate mechanisms and functional context. Such efforts should be grounded in an empirical assessment of phenotypic variability. We tested hypotheses regarding cycle biomarker variability in women from a wealthy industrialized population (Germany) and a resource-limited rural agropastoral population (Bolivia). Ovulatory cycles in both samples displayed marked but nonetheless comparable variability in all cycle biomarkers and similar means/medians for cycle and phase lengths. Notably, cycle and phase lengths are poor predictors of mid-luteal progesterone concentrations. These patterns suggest that global and local statistical criteria for "normal" cycles would be difficult to define. A more productive approach involves elucidating the causes of natural variation in ovarian cycling and its consequences for reproductive success and women's health.

Commuter types identified using clustering and their associations with source-specific PM2.5.

Traffic-related fine particulate matter air pollution (tr-PM2.5) has been associated with adverse health outcomes such as cardiopulmonary morbidity and mortality, with in-vehicle tr-PM2.5 exposure contributing to total personal pollution exposure. Trip characteristics, including time of day, day of the week, and traffic congestion, are associated with in-vehicle PM2.5 exposures. We hypothesized that some commuter characteristics, such as whether commuters travel primarily during rush hour, would also be associated with increased tr-PM2.5 exposures. The commute data consisted of unscripted personal vehicle trips of 46 commuters in the Washington, D.C. metro area over 48-h, with a total of 320 trips. We identified commuter types using sparse K-means clustering, which identifies the hours throughout the day important for clustering commuters. Source-specific PM2.5 over 48 h was estimated using Positive Matrix Factorization. Linear regression was used to estimate differences in source-specific PM2.5 by commuter cluster. Two commuter clusters were identified using the clustering approach: rush hour commuters, who primarily travelled during rush hour, and sporadic commuters, who travelled throughout the day. The hours given the largest weights by sparse K-means were 7-8 a.m. and 6-7 p.m., corresponding to peak travel times. Integrated black carbon (BC) was higher for rush hour commuters (median = 3.1 µg/m3 (IQR = 1.5)) compared to sporadic commuters (2.0 µg/m3 (IQR = 1.9)). Mobile PM2.5, consisting primarily of tailpipe emissions and brake/tire wear, was also higher for rush hour commuters (2.9 µg/m3 (IQR = 1.6)) compared to sporadic commuters (2.1 µg/m3 (IQR = 2.4)), though this difference was not statistically significant in regression models. Estimated differences between commuter types for secondary/mixed PM2.5 and road salt PM2.5 were smaller. Further research may elucidate whether commuter characteristics are an efficient way to identify individuals with highest tr-PM2.5 exposures associated with commuting and to develop effective mitigation strategies.

Estimating exposure to traffic-related PM2.5 for women commuters using vehicle and personal monitoring.

Exposure to traffic-related fine particulate matter air pollution (tr-PM2.5) has been associated with adverse health outcomes including preterm birth and low birthweight. In-vehicle exposure to tr-PM2.5 can contribute substantially to total tr-PM2.5 exposure. Because average commuting habits of women differ from men, a research gap is estimating in-vehicle tr-PM2.5 exposures for women commuters. For 46 women commuters in the Washington, D.C. metro area, we measured personal exposure to PM2.5 during all vehicle trips taken in a 48-h sampling period. We also measured 48-h integrated PM2.5 chemical constituents including black carbon and zinc. We identified trip times using vehicle monitors, specifically on-board diagnostics data loggers and dashboard cameras. For 386 trips, we estimated associations between PM2.5 exposure and trip characteristics using linear mixed models accounting for participant, day, and time of day. Additionally, we estimated associations between rush hour trip PM2.5 and 48-h integrated PM2.5 chemical constituents using linear models. Exposure to PM2.5 during trips was 1.9 µg/m3 (95% confidence interval (CI): 0.9, 2.9) higher than non-trip exposures and rush hour trip exposures were 3.2 µg/m3 (95% CI: 1.8, 4.6) higher than non-trip exposures on average. We did not find differences in PM2.5 exposure by trip length. Although concentrations of tr-PM2.5 chemical constituents were generally positively associated with rush hour trip PM2.5, associations were weak indicating that other settings contribute to total tr-PM2.5 exposure. Our study demonstrates the utility of combining vehicle monitors and personal PM2.5 monitors for estimating personal exposure to tr-PM2.5. Future work will investigate whether additional data collected by vehicle monitors, such as traffic and speed, can be leveraged to better understand tr-PM2.5 exposure among commuters.

A Feasibility Study Assessing Acceptability and Supply Issues of Distributing LPG Cookstoves and Gas Cylinders to Pregnant Women Living in Rural Bangladesh for Poriborton: The CHANge Trial.

Our aim was to develop a protocol for a cluster randomised controlled trial to assess the impact of liquid petroleum gas (LPG) cooking compared to usual cooking on perinatal mortality in pregnant women in rural Bangladesh. We, therefore, aimed to assess the feasibility of the planned trial and the barriers/facilitators of distributing LPG to rural households. We conducted a feasibility study in rural Bangladesh using an iterative design. We included pregnant women, their families, and local LPG stakeholders. We distributed LPG to households for 3 months (3 cylinders) and assessed process issues, acceptability, and cooking/food behaviours. We interviewed LPG stakeholders, and conducted focus groups and in-depth interviews with the users. The initial distribution and uptake of LPG were hampered by process issues, most of these were due to the nonestablished supply chain in the study area. LPG cooking was very acceptable and all users reported a preference for continued use, fuel-sparing was heavily practiced. Safety concerns were an initial issue. LPG stakeholders reported that LPG demand differed by season. This study demonstrated the feasibility of our planned trial and the need for safety messages. These results are relevant beyond our trial, including for programs of LPG fuel promotion.

Identification of Bicycling Periods Using the MicroPEM Personal Exposure Monitor.

Exposure assessment studies are the primary means for understanding links between exposure to chemical and physical agents and adverse health effects. Recently, researchers have proposed using wearable monitors during exposure assessment studies to obtain higher fidelity readings of exposures actually experienced by subjects. However, limited research has been conducted to link a wearer's actions to periods of exposure, a necessary step for estimating inhaled dosage. To aid researchers in these settings, we developed a machine learning model for identifying periods of bicycling activity using passively collected data from the RTI MicroPEM wearable exposure monitor, a lightweight device capable of continuously sampling both air pollution levels and accelerometry parameters. Our best performing model identifies biking activity with a mean leave-one-session-out (LOSO) cross-validation F1 score of 0.832 (unweighted) and 0.979 (weighted). Accelerometer derived features contributed greatly to the model performance, as well as temporal smoothing of the predicted activities. Additionally, we found competitive activity recognition can occur with even relatively low sampling rates, suggesting suitability for exposure assessment studies where continuous data collection for long periods (without recharge) are needed to capture realistic daily routines and exposures.

Exposure to Potentially Harmful E-Cigarette Emissions via Vape Tricks: Protocol for a Mixed-Methods Study.

BACKGROUND: The number of adolescents and adults using e-cigarettes, referred to as vaping, has dramatically increased. E-cigarettes can be used to perform vape tricks by inhaling and exhaling the e-cigarette aerosol in patterns to create visual effects or large clouds. To create these effects, the puffing patterns associated with vape tricks may be different than standard ad-lib e-cigarette usage. The prevalence of vape tricks and the harm associated with exposure to e-cigarette emissions when performing vape tricks is currently unknown. OBJECTIVE: Our objectives are to characterize duration, heart rate, respiratory rate, tidal volume, minute volume, and physical activity metrics associated with the performance of vape tricks and to characterize the emission of e-cigarettes when performing vape tricks in a manner suitable to inform novel exposure modeling. METHODS: The study will recruit e-cigarette users with a history of performing vape tricks. Data collection will occur in two different sessions. In the first session, participants will be asked to puff on their e-cigarette as they normally would for 20 minutes. The second session will be a vape tricks session, where users will be asked to perform a series of up to five different vape tricks with their e-cigarette. Data will be collected through screener surveys, in-person interviews, video recordings, a personal exposure monitor, and a biometric garment. RESULTS: Data analysis is pending and scheduled to take place in the fall of 2019. CONCLUSIONS: This study will be used to assess the feasibility of using a biometric garment to complement environmental and observational data. The approach may provide greater insight into the health risks of performing vape tricks compared to typical e-cigarette use. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/12304.

Impacts of nocturnal breastfeeding, photoperiod, and access to electricity on maternal sleep behaviors in a non-industrial rural Bolivian population.

OBJECTIVES: We tested 4 main predictions, derived from life history theory and self-evident human diurnality, regarding maternal sleep behaviors in a non-industrialized population in which mother-nursling co-sleeping is universal and prolonged: (1) Night breastfeeding incurs a sleep cost to co-sleeping mothers; (2) Night breastfeeding increases with infant age, causing mothers to sleep less; (3) Sleep duration co-varies with darkness duration; (4) Access to electricity reduces sleep duration. DESIGN: Mothers self-recorded and reported nursing and sleep behaviors for a 48-hour period once per month (median = 5 months). SETTING: Rural Bolivian altiplano homesteads, primarily reliant on agropastoralism, scattered throughout the countryside surrounding a main town (altitude 3800 m; 17°14'S, 65°55'W; darkness duration 10-12 hours over the year). PARTICIPANTS: One hundred eighty-four co-sleeping mother-infant pairs (infant age 22-730 days). MEASUREMENTS: Breastfeeding frequency, and retiring and rising times for 885 48-hour observation periods. RESULTS: Maternal sleep duration covaried with darkness duration. Sleep duration was shorter in those with access to electricity (ie, living nearer to town) than those without access (more distant homesteads). Night breastfeeding rate was fairly steady until it began to decline after the first year postpartum. At a given infant age, higher night breastfeeding rates were associated with less maternal sleep. As their infants aged, mothers without electricity slept more, whereas mothers with access slept less. CONCLUSIONS: During the first year postpartum, more frequent night nursing shortens maternal sleep more than any other predictor variable. For older infants, the effect of night nursing diminishes, and even modest "modernization" (eg, access to electricity) is associated with shorter maternal sleep.