Breastfeeding Rates in the Military Are Unchanged Before and After the Onset of the COVID-19 Pandemic.

Introduction: The COVID-19 pandemic brought changes in clinical operations and raised concerns about breastfeeding safety. We investigated the change in breastfeeding rates within a military population, a model of universal health care coverage, and elucidated factors that enhance or deter breastfeeding. Methods: A retrospective analysis was performed on mothers delivering infants ≥35 weeks' gestation at a military treatment facility (MTF) before (PRE) and during (PERI) the pandemic. Demographic data and feeding methods (exclusive, any, and no breastfeeding) from birth to 6 months of life were obtained. The primary outcome compared the breastfeeding rates between PRE and PERI. Logistic regressions identified factors associated with breastfeeding. Results: Of the 372 dyads, 189 (51%) were in PRE and 183 (49%) were in PERI. Exclusive breastfeeding rates in the nursery (77% versus 78%, p = 0.7), at 1 month (70% versus 65%, p = 0.3), at 2 months (65% versus 62%, p = 0.6), 4 months (49% versus 56%, p = 0.2), and 6 months of life (42% versus 47%, p = 0.5) were similar between PRE and PERI. Trends for any breastfeeding were also unchanged. Interactions with a lactation consultant were most strongly associated with exclusive breastfeeding in the nursery (odds ratio 21.88, confidence interval 5.84-82.00, p < 0.001). Discussion: Breastfeeding rates from birth to 6 months of life in infants receiving care at a single MTF were unchanged before and during the pandemic. Access to lactation consultants appears to be a significant contributing factor, and universal health care coverage may have improved access to this resource. Accessibility to breastfeeding resources and education is essential to support and strengthen breastfeeding within the military community.

Extracellular Vesicles as Predictors of Individual Response to Exercise Training in Youth Living with Obesity.

BACKGROUND: Exercise is associated with health benefits, including the prevention and management of obesity. However, heterogeneity in the adaptive response to exercise training exists. Our objective was to evaluate if changes in extracellular vesicles (EVs) after acute aerobic exercise were associated with the responder phenotype following 6-weeks of resistance training (RT). METHODS: This is a secondary analysis of plasma samples from the EXIT trial (clinical trial#02204670). Eleven sedentary youth with obesity (15.7 ± 0.5 yrs, BMI ≥95th percentile) underwent acute exercise (60% HRR, 45 min). Blood was collected at baseline [AT0 min], during [AT15-45 min], and 75 min post-recovery [AT120], and EVs purified using size exclusion chromatography from extracted plasma. Afterward, youth participated in 6-weeks RT and were categorized into responders or non-responders based on changes in insulin sensitivity. RESULTS: We assessed EV biophysical profile (size, zeta potential, protein yield, and EV subtype protein expression) in a single-blind fashion. Overall, there was a general increase in EV production in both groups. Average EV size was larger in responders (~147 nm) vs. non-responders (~124 nm; p < 0.05). EV size was positively associated with absolute change in Matsuda index (insulin sensitivity) following RT (r = 0.44, p = 0.08). EV size distribution revealed responders predominantly expressed EVs sized 150-300 nm, whereas non-responders expressed EVs sized 50-150 nm (p < 0.05). At baseline, responders had ~25% lower TSG101, ~85% higher MMP2 levels. EV protein yield was higher in responders than non-responders at AT15 (p < 0.05). CONCLUSIONS: Our data suggest that youth with obesity that respond to RT produce larger EVs that are TSG101+ and CD63+, with increased EV protein yield during acute exercise.

Temporal correspondence of selenium and mercury, among brine shrimp and water in Great Salt Lake, Utah, USA.

The specific source of high burdens of selenium (Se) and mercury (Hg) in several bird species at Great Salt Lake (GSL) remain unknown. Frequent co-located water and brine shrimp samples were collected during 2016 through 2017 to identify potential correlations of element concentrations among brines and brine shrimp, a keystone species in the GSL. Like many aquatic systems, GSL is characterized by elevated methylmercury (MeHg) in deep waters. However, in contrast to thermally-stratified aquatic systems, biota in the salinity-stratified GSL do not reside in its deep waters, obscuring the presumed relationship between elevated MeHg in biota and in the deep brine. Brine shrimp and water column (shallow and deep, filtered and unfiltered) samples were collected from six sites spanning the South Arm of GSL approximately every other month. Mercury concentrations in brine shrimp (on average 89% of which is MeHg) were correlated only with total mercury in surface filtered water, and displayed little spatial variability, but consistent seasonal trends across the two sampled years. In contrast to Hg, temporal correspondence was observed between Se concentrations in brine shrimp and those in all water samples regardless of filtering and depth, with maxima and minima at higher-than-seasonal frequency. The data suggest a spatially diffuse source of bioavailable mercury to the shallow brine that responds to seasonal influences, for which the underlying deep brine, surficial sediments, and overlying atmosphere were evaluated in terms of potential temporal correspondence to shallow brine and brine shrimp Hg concentrations, as well as potential to mix across the extent of the shallow brine. Bioaccumulation factors were at the low end of those reported for marine systems, and decreased at higher trace element concentrations in water.