Annals of Human Biology最新文献

Background: Head orientation during photography can distort facial shape, but this is rarely considered in cross-population studies focusing on facial morphology and its perception.

Aim: To assess how head positioning (Frankfurt Horizontal [FH] vs. natural position [NP]) affects facial shape and trait perception across two ethnic populations.

Subjects and methods: Facial photographs were collected from Buryats of Mongolian descent (N = 148) and Russians of European descent (N = 155). Geometric morphometrics were used to compare the facial shapes in the FH and NP positions. Independent rater groups with similar population origins, Kalmyks (N = 162) and Russians (N = 242), evaluated perceived aggressiveness and attractiveness based on these portraits.

Results: Head orientation significantly altered facial shape, particularly among the Buryat group. Despite the larger facial sexual dimorphism in the Buryat group, sex differences were more pronounced in FH across both samples. Correlations between facial shape and body metrics (height, Body Mass Index, and body fat mass) were stronger in FH. Ratings of male aggressiveness and female attractiveness were consistently influenced by head position across both rater populations and sexes.

Conclusion: Head positioning introduces systematic bias into facial shape analysis and perception. Failure to control for this factor may compromise study comparability and distort meta-analytic findings.

Background: Accurate assessment of aerobic fitness is essential in youth soccer. The Yo-Yo Intermittent Recovery Test Level 1 (YYIR1) provides a practical estimate of maximal oxygen uptake (VO_2max), but its agreement with laboratory values across maturity stages remains uncertain.

Aim: To examine the relationship and agreement between YYIR1 performance and laboratory-measured VO_2max in adolescent male soccer players, and to assess whether biological maturation, playing position, and running economy (RE) affect estimation consistency.

Subjects and methods: Twenty-three players (13.7 ± 0.5 years) completed YYIR1 and laboratory treadmill tests (LTT). VO_2max was measured during LTT and estimated from YYIR1 performance. Effects of biological maturation [pre-, circa-, post-peak height velocity (PHV)], position, and RE were analysed.

Results: YYIR1 underestimated VO_2max by 5.2% versus LTT (p < 0.001) but showed strong correlation (r = 0.82). Bland-Altman analysis indicated acceptable agreement. Estimation consistency was higher in pre- and circa-PHV players, though subgroup sizes were small. Maturation, position, and RE had no significant effects.

Conclusions: YYIR1 is strongly associated with laboratory VO_2max but systematically underestimates it. Coaches may use YYIR1 distance to monitor intermittent endurance, while interpreting estimated VO_2max with caution. Larger, maturity-balanced samples are needed to clarify subgroup differences and improve youth-specific prediction accuracy.

Background: It is uncertain if age of menarche continues to decline. There has been no systematic meta-analysis of ages at menarche in Norway the past three decades.

Aim: To conduct a systematic review and meta-analysis to assess secular trends in menarcheal age in Norway.

Subjects and methods: A literature search was performed in PubMed, Web of Science, and Embase to identify studies including ages at menarche from healthy females. Re-analysis of data from 16 surveys were included together with 17 published studies in a meta-analysis using weighted regression analyses with fitted restricted cubic splines. Each study or dataset was given a random intercept to account for within-survey correlation.

Results: In total, 783,757 observations were included in the meta-analysis. Three distinct periods were identified. For women born 1840-1910, a large and stable decline with -0.14 to -0.20 years per decade (y/d) was observed, whilst in women born 1910-1950 this decline accelerated up to -0.30 y/d. The third period of women born 1950-2008 saw a small and stable decline with -0.06 to -0.08 y/d.

Conclusion: Age at menarche declined throughout the study period from 1840-2008, but more rapidly in girls born between 1910-1950. Data suggest an ongoing, modest decline.

Background: The issues of underweight and short stature are significant yet underrepresented in the literature.

Aim: This study examines the prevalence of changes in underweight and short stature among Polish youth from 1938 to 2020.

Subjects and methods: Utilising five cross-sectional data sets from Kraków, Poland, the study analysed 24,655 children and adolescents aged 3-18 years. Height and weight were measured, with BMI calculated. Underweight was determined using Cole's cut-off points, while short stature was defined as height below -2 standard deviations from the mean for age and sex.

Results: For girls, the prevalence of underweight remained stable at approximately 9.5% from 1938 to 2020, peaking in 1983, particularly during puberty, before declining in subsequent cohorts. In boys, underweight prevalence varied more, from 5.6% in 1938 to 11.1% in 1983, with a steady decline thereafter. Short stature prevalence for both sexes remained low (1.5-2.5%) and unchanged over 85 years.

Conclusion: Underweight prevalence increased significantly from 1938 to 1983, reflecting adverse environmental conditions, but has decreased in the last four decades, highlighting socioeconomic influences. Both underweight and short stature can significantly affect children's health.

Background: Climate change is a growing threat to population health, with dangerous combinations of heat and humidity increasing in frequency, particularly in South Asia. Evidence suggests that high temperatures and heat stress influence breastfeeding behaviour and may lead to suboptimal infant and young child nutrition.

Aim: Few studies have quantified the relationship between ambient heat and breastfeeding. Here we evaluate associations between wet-bulb temperature and daily breastfeeding patterns in a rural community in Bangladesh.

Subjects and methods: We used 23 months of daily time-diary data from 68 maternal-child dyads and regional wet-bulb temperatures to test the hypothesis that increased heat and humidity negatively influence breastfeeding outcomes among Shodagor fisher-traders.

Results: We found that higher wet-bulb temperatures predicted reduced daily breastfeeding time allocation, particularly among fishers, and drove shifts towards increased night-time and decreased mid/late morning feeding. Maternal occupation and the interaction of child age with heat strongly influenced diurnal breastfeeding patterns.

Conclusion: These results highlight an important role of maternal work on infants' vulnerability to environmental stress. Dyads' ability to behaviourally compensate for extreme heat may be constrained by extended heatwaves, humidity, and economic circumstances, suggesting that climate change will likely exacerbate heat-related risks to global child health going forward.

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: Cardiorespiratory fitness (CRF) has become a significant focus in the field of public health. CRF is considered a strong predictor of health outcomes. However, cardiorespiratory fitness levels of children and adolescents are declining.

Aims: (1) To analyse the cardiorespiratory fitness levels of children and adolescents in China, focusing on maximum oxygen uptake (VO₂max), maximum heart rate (HRmax), peak oxygen uptake (Peak VO₂) and 20-metre shuttle run test (20 m-SRT). (2) To provide baseline data, with the goal of supporting the development of sports programs, intervention strategies, and public health decision-making.

Subjects and methods: A meta-analysis was conducted using 30 studies selected from five databases.

Results: The average performance on 20 m-SRT for Chinese children and adolescents was 34.67 laps, with a VO₂max of 46.47 ml/kg/min, HRmax of 195.02 bpm, and Peak VO₂ of 48.58 ml/kg/min. Boys outperformed girls in VO₂max, 20 m-SRT, and HRmax, although the differences in HRmax and Peak VO₂ were not statistically significant. Tibetan children showed better performance than Han children in three indicators with no significant differences found.

Conclusion: Cardiorespiratory fitness in Chinese children and adolescents is within a healthy range but not optimal. Boys generally perform better than girls, and Tibetan children outperform Han children.

Background: The impact of environmental iodine and fluorine levels on thyroid function indicators in a healthy population is of crucial significance for developing scientifically sound prevention and control strategies to safeguard residents' health.

Aim: To investigate impacts of iodine and fluorine levels in the environment on thyroid function indicators among a healthy population in Hebei Province, China.

Subjects and methods: Water samples were collected and the area was divided into six regions based on different iodine and fluorine levels: purely high-iodine area, purely low-iodine area, purely adequate-iodine area, high-iodine high-fluorine area, low-iodine high-fluorine area, and purely high-fluorine area. Probability proportionate sampling was used to select 1-2 administrative villages in each region. In each selected village, residents aged 8 and above who had lived there continuously for at least two years were examined. A thyroid survey was conducted, blood samples were taken to check thyroid function indicators, urinary iodine and fluorine levels were measured, and the proportion of residents consuming iodised salt was recorded.

Results: A total of 2400 residents from six regions were included in the study. There was no significant difference in the general data of the six regions (p > 0.05). However, there were significant differences in the comparisons of Thyroid-Stimulating Hormone (TSH), Free Thyroxine (FT4) and Free Triiodothyronine (FT3) levels (p < 0.05). There was no significant difference in the comparison of the proportion of iodised salt consumption among the six regions (X2/F Value, p = 0.160). TSH was negatively correlated with water iodine levels (r = -0.543, p < 0.05), and positively correlated with water fluorine levels (r = 0.281, p < 0.05). FT4 and FT3 were positively correlated with water iodine levels (r = 0.595, p < 0.05; r = -0.117, p < 0.05), and negatively correlated with water fluorine levels (r = 0.543, p < 0.05; r = -0.486, p < 0.05).

Conclusion: High environmental iodine levels significantly impact thyroid function indicators. Residents in areas with high iodine levels in water sources should take early measures to prevent and control thyroid diseases and undergo regular check-ups.

Context: The relationship between methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR) gene polymorphisms and H-type hypertension susceptibility has been deeply analysed, but the conclusions are not consistent. Therefore, we carried out a meta-analysis aimed at assessing the relationship exactly.

Methods: Six English databases (PubMed, Embase, EBSCO, ScienceDirect, Cochrane Library, and Web of Science) and four Chinese databases (China Biological Medicine, WanFang, China Science and Technology Journal, and China National Knowledge Infrastructure) were used for searching studies from inception to August 2023. MTHFR C677T/A1298C and MTRR A66G genetic polymorphisms were evaluated.

Results: A total of 24 papers were included in our research, including 3649 H-type hyperpietics, 2772 non-H-type hyperpietics, and 2149 healthy controls. Our analysis shows that MTHFR C677T polymorphism showed significant association with H-type hypertension in both healthy individuals and non-H-type hyperpietics (TT vs. CC: OR = 3.43, 95% CI = 2.48-4.75). Further subgroup analysis based on geography revealed that homocysteine levels in the southern Chinese population were more susceptible to MTHFR C677T polymorphism (p < 0.05). However, there was no significant association in all genetic models for the polymorphisms of MTHFR A1298C and MTRR A66G.

Conclusion: MTHFR C677T polymorphisms are associated with H-type hypertension in non-H-type hyperpietics and healthy individuals.

Background: Recent fossil discoveries have emphasised the diversification of brain and body size in Plio-Pleistocene fossil hominids.¹ Homo floresiensis has been described as having brain and body size smaller than any living humans, and the Homo luzonensis dentition suggests that this taxon was also diminutive.

Aim: To explore the hypothesis that third molar reduction in genus Homo may be linked to changes in brain size.

Subjects and methods: We assessed the phenotypic relationship between relative third molar length, endocranial volume, body mass, and maxillary and mandibular postcanine dental metrics for n = 15 hominid taxa.

Results: Maxillary and mandibular relative third molar lengths are significantly correlated with endocranial volume and body mass in Plio-Pleistocene hominids, but Homo floresiensis deviates from this scaling relationship. The molar lengths and proportions of Homo luzonensis are comparable to H. floresiensis, suggesting that these taxa were similar in size.

Conclusion: Geologically older hominid taxa tend to have relatively longer third molars and smaller endocranial volumes. We discuss the effects of growth rates on the dentition and explore the hypothesis that both H. floresiensis and H. luzonensis represent short-statured populations that evolved on islands via insular nanism and postnatal growth restriction.