Annals of Human Biology最新文献

Background: The built environment buffers residents of large cities, such as New York (NYC), from exposure to low temperatures. Furthermore, average winter temperatures are rising in NYC due to climate change. The degree to which NYC residents exhibit metabolic adaptations to cold stress is currently unclear.

Aim: This study quantified variation in brown adipose tissue (BAT), energy expenditure (EE), and ambient temperature among NYC residents.

Subjects and methods: We recruited 46 adults (31 females; 15 males) and quantified anthropometrics, change in EE, and BAT thermogenesis after a cooling condition in the lab. A subsample of 21 participants wore temperature loggers for three days in order to quantify ambient temperature exposure.

Results: BAT thermogenesis was not significantly associated with change in EE. Participants that were exposed to lower average temperatures exhibited greater BAT thermogenesis (p = 0.013). Change in EE, however, was not significantly associated with time spent outside nor average temperature exposure.

Conclusion: Our study provides mixed evidence for the role of BAT thermogenesis in metabolic adaptations to cold stress among NYC residents. Many young adults in NYC are exposed to minimal amounts of cold stress, and this trend is likely to be exacerbated by climate change.

Background and aim: We provide ethnographic, photovoice, and psychosocial stress data (food and water insecurity, potentially traumatic events, stress biomarkers) documenting the joys, hazards, and stressors of adolescents engaging in climate-sensitive pastoralist livelihoods in a global climate change hot spot. We aim to holistically capture socio-environmental relationships characterised by climate sensitive livelihoods and forms of precarity exacerbated by climate change.

Subjects and methods: Qualitative and quantitative methods were integrated to understand the embodied toll of hazards that Samburu pastoralists faced based on a sample of 161 young people. Quantitatively, we tested for associations of psychosocial stressors with both psychological distress and cell-mediated immune function (assessed through differences in IgG antibodies to Epstein-Barr virus).

Results: Qualitatively, young Samburu reported drought, food and water insecurity, wildlife encounters, and war exposure. Girls overall endorsed more posttraumatic stress symptoms, although boys reported relatively more stressors; girls overall and young people in the hotter subregion manifested more immune dysregulation.

Conclusion: In spite of important differences between climate subregions, the common elements throughout the Samburu pastoralist leanscape include food and water insecurity and overall precarity exacerbated by drought and climate change. Community-driven interventions are needed to reduce precarity for young people pursuing pastoralist livelihoods.

Background: Infants given mothers' milk have higher resistance against infections than formula-fed counterparts. This protection is likely multifactorial, with roles for both milk immune factors and nutrients, particularly under elevated nutritional and disease stress.

Aim: This study evaluated several milk nutrients/immune factors to assess associations with infant infectious disease during a severe drought.

Subjects and methods: The study analysed morbidity recall data from Kenyan mother-infant dyads surveyed during a historic drought (n 84). Predictors of interest in logistic regression models of infant infections included milk sIgA, lactoferrin, retinol, folate receptor-α, fat, protein, and lactose. Adjustment variables included dyadic demographic characteristics and maternal infection. Akaike Information Criterion guided model fit assessment. Interactions between variables were allowed in the best-fit model.

Results: In the best-fit model, lactose was inversely (OR 0.93; 90% CI 0.89, 0.97), and maternal infection was positively (OR 2.80; 90% CI 1.04, 7.52) associated with infant infection. Milk immune factors (sIgA, lactoferrin) were not included in the final models.

Conclusion: Mothers' milk may protect infants against infection through a broad range of immune and nutrient components. In the context of severe drought with heightened nutritional and disease stress, lactose may protect against infection or decrease in the presence of an infection.

Background: Y-chromosome haplogroup C2a-M48-F8472, a unique paternal line in the ancient Xiongnu population, is concentrated in the modern Han people. The most closely related lineage of this paternal lineage is mainly distributed in Tungusic-, Mongolic-, and Turkic-speaking populations.

Aim: To investigate the formation process of this unique distribution state.

Subjects and methods: In total, 36 sequences of haplogroup C2a-M48-F8472 were analysed to generate a revised phylogenetic tree with age estimation and to explore the geographic distribution pattern.

Results: The results suggested that northern China is likely the diffusion centre of this paternal haplogroup. This lineage is concentrated in the Liu clan () of Han populations and may have originated in the Tuge tribe () of Xiongnu populations. The initial expansion (∼2,600 years ago) and the second phase of expansion (∼1,570 years ago) of haplogroup C2a-M48-F8472 coincide with the earlier appearance and later disappearance of the Tuge tribe. As a sub-clade of M48, the history of F8472 suggested that ancient peoples related to Tungusic-speaking populations were intricately connected with the demographic history of populations in the Mongolian Plateau.

Conclusion: The appearance of this paternal line in the Han population is helpful for understanding the mixed history of ancient and modern people in the Mongolian Plateau and Central China.