SciCombinator

Discover the most talked about and latest scientific content & concepts.

Journal: The Journal of clinical endocrinology and metabolism

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Context:Colonization of the gastrointestinal tract with methanogenic archaea (methanogens) significantly affects host metabolism and weight gain in animal models, and breath methane is associated with a greater body mass index (BMI) among obese human subjects.Objective:The objective of the study was to characterize the relationship between methane and hydrogen on breath test (as a surrogate for colonization with the hydrogen requiring methanogen, Methanobrevibacter smithii), body weight, and percent body fat in a general population cohort.Design and Subjects:This was a prospective study (n = 792) of consecutive subjects presenting for breath testing.Setting:The study was conducted at a tertiary care center.Outcome Measurements:BMI and percent body fat were measured.Results:Subjects were classified into 4 groups based on breath testing: normal (N) (methane <3 ppm and hydrogen <20 ppm at or before 90 minutes); hydrogen positive only (H+) [methane <3 ppm and hydrogen ≥20 ppm); methane positive only (M+) (methane ≥3 ppm and hydrogen <20 ppm), or methane and hydrogen positive (M+/H+) (methane ≥3 ppm and hydrogen ≥20 ppm]. There were significant differences in age but not in gender across the groups. After controlling for age as a confounding variable, M+/H+ subjects had significantly higher BMI than other groups (N: 24.1 ± 5.2 kg/m(2); H+: 24.2 ± 4.5 kg/m(2); M+: 24.0 ± 3.75 kg/m(2); M+/H+: 26.5 ± 7.1 kg/m(2), P < .02) and also had significantly higher percent body fat (N: 28.3 ± 10.0%; H+: 27.5 ± 9.0%; M+: 28.0 ± 8.9%; M+/H+; 34.1 ± 10.9%, P < .001).Conclusions:The presence of both methane and hydrogen on breath testing is associated with increased BMI and percent body fat in humans. We hypothesize that this is due to colonization with the hydrogen-requiring M smithii, which affects nutrient availability for the host and may contribute to weight gain.

Concepts: Anaerobic digestion, Body weight, Nutrition, Obesity, Methanogen, Mass, Archaea, Body mass index

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Low blood glucose concentrations during the discharge day may affect 30-day readmission and post hospital discharge mortality rates.

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Current approaches to antenatal vitamin D supplementation do not account for interindividual differences in 25-hydroxyvitamin D (25(OH)D) response.

Concepts: Vitamins, Vitamin D

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Spexin is a novel peptide that is implicated in obesity and related energy homeostasis in animals and adult humans. Little is known about its role in children.

Concepts: Homeostasis, Novel, Adult, Obesity, Childhood obesity

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Marine long-chain omega-3 fatty acids have been positively related to markers of fecundity in both men and women. However, seafood, their primary food source, can also be a source of toxicants, which may counteract the reproductive benefits.

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Context:Testosterone (T) levels decline with age and lower T has been associated with increased mortality in aging men. However, the associations of its metabolites, dihydrotestosterone (DHT) and estradiol (E2), with mortality are poorly defined.Objective:We assessed associations of T, DHT, and E2 with all-cause and ischemic heart disease (IHD) mortality in older men.Participants:Participants were community-dwelling men aged 70 to 89 years who were residing in Perth, Western Australia.Main Outcome Measures:Plasma total T, DHT, and E2 were assayed using liquid chromatography-tandem mass spectrometry in early morning samples collected in 2001 to 2004 from 3690 men. Deaths to December 2010 were ascertained by data linkage.Results:There were 974 deaths (26.4%), including 325 of IHD. Men who died had lower baseline T (12.8 ± 5.1 vs 13.2 ± 4.8 nmol/L [mean ± SD], P = .013), DHT (1.4 ± 0.7 vs 1.5 ± 0.7 nmol/L, P = .002), and E2 (71.6 ± 29.3 vs 74.0 ± 29.0 pmol/L, P = .022). After allowance for other risk factors, T and DHT were associated with all-cause mortality (T: quartile [Q] Q2:Q1, adjusted hazard ratio [HR] = 0.82, P = .033; Q3:Q1, HR = 0.78, P = .010; Q4:Q1, HR = 0.86, P > .05; DHT: Q3:Q1, HR = 0.76, P = .003; Q4:Q1, HR = 0.84, P > .05). Higher DHT was associated with lower IHD mortality (Q3:Q1, HR = 0.58, P = .002; Q4:Q1, HR = 0.69, P = .026). E2 was not associated with either all-cause or IHD mortality.Conclusions:Optimal androgen levels are a biomarker for survival because older men with midrange levels of T and DHT had the lowest death rates from any cause, whereas those with higher DHT had lower IHD mortality. Further investigations of the biological basis for these associations including randomized trials of T supplementation are needed.

Concepts: Mass spectrometry, Ischaemic heart disease, Estradiol, Ischemia, Epidemiology, Dihydrotestosterone, Testosterone, Death

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Liposuction is suggested to result in long-term body fat regain that could lead to increased cardiometabolic risk. We hypothesized that physical activity could prevent this effect.

Concepts: Randomized controlled trial, Dieting, Obesity

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There is a likely genetic component to gender dysphoria, but association study data have been equivocal.

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Shift work, which imposes a habitual disruption in the circadian system, has been linked to increased incidence of cardiometabolic diseases, and acute circadian misalignment alters various metabolic processes. However, it remains unclear whether day-to-day circadian dysregulation contributes to these risks beyond poor sleep and other behavioral characteristics.

Concepts: Night owl, Lark, Melatonin, Chronotype, Sleep, Circadian rhythms, Circadian rhythm sleep disorder, Circadian rhythm