Is digit ratio (2D:4D) a biomarker for lactate? Evidence from a cardiopulmonary test on professional male footballers.

BACKGROUND: Lactate accumulation is associated with vigorous exercise, cardiovascular disease and a number of cancers. Digit ratio (2D:4D) has also been linked to oxygen metabolism, myocardial infarction and various cancers. Such similarities suggest the possibility that 2D:4D is a biomarker of lactate. Here, we consider the relationship between 2D:4D and lactate during an incremental cardiopulmonary exercise test. METHOD: The participants were male professional football players. The treadmill test began at a speed of 8 km/h when the first lactate measurement was taken. The speed was increased by 2 km/h every 3.15 min, with measurements at 10, 12, 14 and 16 km/h. RESULTS: There were 72 Caucasian and 7 Black participants, results are reported for the most numerous group. Lactate levels increased with running speed and were not correlated with age, body size or body composition. Median splits of digit ratios (right, left and right-left 2D:4D [Dr-l]) were calculated. In comparison to the Low ratio group, the High ratio group showed higher lactate levels across speeds. Effect sizes varied from very large to huge (right 2D:4D), large (left 2D:4D) and medium (Dr-l). At the individual level, positive correlations between digit ratios and lactate at the five different speeds varied from large (right 2D:4D), medium (left 2D:4D) and small (Dr-l). CONCLUSION: There were large positive associations between right 2D:4D and lactate at all running speeds. We discuss our findings in relation to oxygen metabolism and suggest that 2D:4D may be a biomarker for lactate in the wider context of the latter's importance in health and disease.

The associations between digit ratio (2D:4D and right - left 2D:4D), maximal oxygen consumption and ventilatory thresholds in professional male football players.

INTRODUCTION: Digit ratio (2D:4D: the relative length of the 2nd and 4th digit) is thought to be a negative correlate of prenatal testosterone. The 2D:4D is related to oxygen metabolism, but the precise nature of this relationship is unclear. The purpose of the present study was to consider associations between digit ratios (right 2D:4D, left 2D:4D, right-left 2D:4D [Dr-l]) and VO2max and ventilatory thresholds (VT1 and VT2). METHODS: One hundred and thirty-three Caucasian (n = 133) professional football players competing in Cyprus participated in the study. Players underwent anthropometric measurements, and digit lengths were measured from hand scans. They also completed an incremental cardiopulmonary test to exhaustion on a treadmill. RESULTS: There were negative correlations between digit ratios and VO2max (right 2D:4D, r = -.65; left 2D:4D r = -.37, both p < .0001; Dr-l r = -.30, p = .0005). There were no relationships between digit ratios and VT1. For VT2, there were negative relationships with digit ratios (right 2D:4D, r = -.43, p < .0001; left 2D:4D, r = -.21 and Dr-l, r = -.21, both p = .02). Digit ratios are negatively related to VO2max with large (right 2D:4D) and medium (left 2D:4D, Dr-l) effect sizes. For VT2, there were also negative correlations, which were medium (right 2D:4D) and small (left 2D:4D, Dr-l). CONCLUSION: Our findings may help clarify the relationships between digit ratios and high-intensity actions for extended periods, which are dependent on efficient oxygen metabolism.

Analysis of epigenetic clocks links yoga, sleep, education, reduced meat intake, coffee, and a SOCS2 gene variant to slower epigenetic aging.

DNA methylation (DNAm) clocks hold promise for measuring biological age, useful for guiding clinical interventions and forensic identification. This study compared the commonly used DNAm clocks, using DNA methylation and SNP data generated from nearly 1000 human blood or buccal swab samples. We evaluated different preprocessing methods for age estimation, investigated the association of epigenetic age acceleration (EAA) with various lifestyle and sociodemographic factors, and undertook a series of novel genome-wide association analyses for different EAA measures to find associated genetic variants. Our results highlighted the Skin&Blood clock with ssNoob normalization as the most accurate predictor of chronological age. We provided novel evidence for an association between the practice of yoga and a reduction in the pace of aging (DunedinPACE). Increased sleep and physical activity were associated with lower mortality risk score (MRS) in our dataset. University degree, vegetable consumption, and coffee intake were associated with reduced levels of epigenetic aging, whereas smoking, higher BMI, meat consumption, and manual occupation correlated well with faster epigenetic aging, with FitAge, GrimAge, and DunedinPACE clocks showing the most robust associations. In addition, we found a novel association signal for SOCS2 rs73218878 (p = 2.87 × 10-8) and accelerated GrimAge. Our study emphasizes the importance of an optimized DNAm analysis workflow for accurate estimation of epigenetic age, which may influence downstream analyses. The results support the influence of genetic background on EAA. The associated SOCS2 is a member of the suppressor of cytokine signaling family known for its role in human longevity. The reported association between various risk factors and EAA has practical implications for the development of health programs to improve quality of life and reduce premature mortality associated with age-related diseases.

Introduction of a multiplex amplicon sequencing assay to quantify DNA methylation in target cytosine markers underlying four selected epigenetic clocks.

BACKGROUND: DNA methylation analysis has proven to be a powerful tool for age assessment. However, the implementation of epigenetic age prediction in diagnostics or routine forensic casework requires appropriate laboratory methods. In this study, we aimed to compare the performance of large-scale DNA methylation analysis protocols that show promise in terms of accuracy, throughput, multiplexing capacity, and high sensitivity. RESULTS: The protocols were designed to target a predefined panel of 161 genomic CG/CA sites from four known estimators of epigenetic age-related parameters, optimized and validated using artificially methylated controls or blood samples. We successfully targeted 96% of these loci using two enrichment protocols: Ion AmpliSeq™, an amplicon-based method integrated with Ion Torrent S5, and SureSelectXT Methyl-Seq, a hybridization-based method followed by MiSeq FGx sequencing. Both protocols demonstrated high accuracy and robustness. Although hybridization assays have greater multiplexing capabilities, the best overall performance was observed for the amplicon-based protocol with the lowest variability in DNA methylation at 25 ng of starting DNA, mean observed marker coverage of ~ 6.7 k reads, and accuracy of methylation quantification with a mean absolute difference between observed and expected methylation beta value of 0.054. The Ion AmpliSeq method correlated strongly with genome-scale EPIC microarray data (R = 0.91) and showed superiority in terms of methylation measurement accuracy. Method-to-method bias was accounted for by the use of linear transformation, which provided a highly accurate prediction of calendar age with a mean absolute error of less than 5 years for the VISAGE and Hannum age clocks used. The pace of aging (PoAm) and the mortality risk score (MRS) estimators included in our panel represent next-generation clocks, were found to have low to moderate correlations with the VISAGE and Hannum models (R < 0.75), and thus may capture different aspects of epigenetic aging. CONCLUSIONS: We propose a laboratory tool that allows the quantification of DNA methylation in cytosines underlying four different clocks, thus providing broad information on epigenetic aging while maintaining a reasonable number of CpG markers, opening the way to a wide range of applications in forensics, medicine, and healthcare.

The impact of exposure to tobacco smoking and maternal trauma in fetal life on risk of migraine.

Introduction: Prenatal period is the key time in human development. Many prenatal factors are well-known and increase the risk of developing diseases' after birth. Few studies indicated the link between the prenatal period and the prevalence of migraine in childhood and adolescence so far. We decided to broaden current knowledge and investigate whether the prenatal factors influence the prevalence of migraine in adulthood. The objective of this study is to provide evidence of relationship between in utero environment and risk of migraine. Methods: In total 266 females (136 in the migraine group, 130 in the control group) and 80 males (35 in the migraine group, 45 in the control group), aged 18-65 participated in the study. The quality of prenatal environment was characterized on the basis of mother's and father's education, tobacco smoke exposure, alcohol consumption, and traumatic event during pregnancy, which are considered as prenatal factors and affect on fetal development. Results: Migraine occurrence in adulthood was significantly associated with maternal tobacco smoking during pregnancy (OR 3.42, 95% CI 1.54-7.61, p = 0.036) and traumatic event during pregnancy (OR 2.27, 95% CI 1.24-4.13, p = 0.020). Discussion: Our study suggests that the fetal programming effect of tobacco smoking exposure and maternal trauma is not limited to prenatal life and is suggested as having a role in adulthood. Our findings support evidence that migraine adulthood can be partly influenced by early life conditions.

Description of the menstrual cycle status, energy availability, eating behavior and physical performance in a youth female soccer team.

The aim of the study was to describe the menstrual status and perception, risk of low energy availability (LEA) and the presence of orthorexia nervosa (ON) in youth female from a soccer team. Also, verify the possible effect of LEA and ON on physical performance. Data from 19 female players (14.6 ± 1.42 yr) belonging to a soccer team from Cyprus was taken during pre-season. The menstrual cycle status was evaluated by specific questions, LEA by the Low Energy Availability in Females Questionnaire (LEAF-Q), ON by the ORTO-R questionnaire and physical performance by jump, handgrip and cardiorespiratory exercise tests. Players were separated into the risk of LEA and ON. Comparison and correlation tests were performed with a significance set at p < 0.05. As the main results, 66.7% of players perceived that the menstrual period affects their performance in the game, 83.3% did not communicate with coaches about their menstrual cycle; the prevalence of risk of LEA was 26.3%; players with risk of LEA also presented higher scores ON; neither LEA nor ON presented a significant association with players performance. The findings highlighted that youth players perceived an impact of the menstrual period on performance, but did not communicate with the coach about it. Players with the risk of LEA and high values of ON seem not to be associated with a decrease in physical performance during the pre-season evaluation. Attention is required as the players were assessed once. Monitoring these parameters throughout the sports season is recommended to obtain better clarification about the topic.

Primary Headaches and Physical Performance: A Professional Youth Female Soccer Team Study.

The vast majority of the research on acute post-traumatic incidents in athletes focuses on migraines. Physical exercise might reduce the frequency of migraines as well as trigger a migraine attack. The objectives of the study were to evaluate primary headache prevalence in professional young female soccer players and to assess whether headaches are related to physical performance. To the best of our knowledge, this is the first study that has considered the relationship between primary headaches and physical performance assessment. The research was conducted in 19 females aged 12-17 from a professional youth soccer academy. Players completed a questionnaire about health status and then performed laboratory physical tests (e.g., cardiopulmonary tests, countermovement and squat jumps, handgrip, sit-and-reach tests). Subsequently, players were separated into a headache group and a headache-free control group. In the analysed group, eight female players (42%) suffered from primary headaches. Among the performance parameters, a significant result was found in terms of flexibility. Females from the headache group had higher results in the sit-and-reach test than females from the control group (p = 0.029). Flexibility as well as mobility in migraine patients is an area with significant potential for further investigation, as little research has been conducted to date.

Maternal Age and Behavior during Pregnancy Affect the 2D:4D Digit Ratio in Polish Children Aged 6-13 Years.

BACKGROUND: The length of the second and fourth finger calculated as a ratio (2D:4D) is a marker of prenatal exposure to sex hormones. Higher exposure to testosterone is related to a lower 2D:4D digit ratio, and inversely, higher exposure to estrogen is related to a higher 2D:4D. The digit ratio in humans (prenatally determined by sex hormone levels and androgen receptor activity) is associated with multiple biological, cognitive, and behavioral traits, as well as health in later life. The aim of this study was to verify if maternal traits during pregnancy are associated with 2D:4D among their children. METHODS: We investigated 537 boys, 646 girls, and their mothers. The investigation consisted of a questionnaire and a measurement part. In the questionnaire, we included questions about maternal traits during pregnancy such as: illnesses, active and passive smoking, work activity, psychological trauma (death or serious illness of a loved one, divorce, job loss), and age. We performed length measurements of the second and fourth fingers on both hands for both study groups. RESULTS: The GLM analysis showed that children of smoking mothers were characterized by a higher 2D:4D R as compared to their peers whose mothers did not smoke (ß = 0.10, p = 0.0008). In turn, the offspring of women who worked during pregnancy exhibited lower 2D:4D R values than the children of women who did not work (ß = -0.07, p = 0.0233). It should be noted, however, that the effects of those maternal factors were small, as each of them explained less than 1% of 2D:4D R in the population, adjusted for child age and sex. Pearson's linear correlation revealed that maternal age was negatively correlated with 2D:4D R in daughters (r = -0.11, p = 0.0137), but not in sons (r = 0.02, p = 0.6908). The negative correlation of 2D:4D R with maternal age indicates that the daughters of older mothers exhibited lower values of that ratio relative to the same-age daughters of younger mothers. CONCLUSIONS: For both study groups, the right-hand digit ratio was positively correlated with maternal smoking and negatively with maternal work during pregnancy. Maternal age during pregnancy was negatively related to right hand 2D:4D only among girls.

Risk of Migraine in Europeans with Low Melanin Levels-A Population Based Case-Control Study.

Populations with a relatively low concentration of melanin, e.g., inhabitants of Europe, North America, and Australia, are the most vulnerable to the harmful effects of UV radiation. Individuals with fair phototype are at greatest risk of developing skin cancer. Several neurological studies present that light skin may modify the risk of Alzheimer's and Parkinson's diseases. However, the relationship between migraine and skin pigmentation has not been investigated yet. The objective of this study is to provide evidence of the relationship between skin pigmentation and migraine prevalence in adults. We examined a group of 148 adults (33 men, 115 women) with migraine and a control group of 107 adults (43 men, 64 women). Parameters of skin pigmentation (melanin index, erythema index, CIElab, and RGB scales) were measured using a DSM II Cortex Technology dermospectrophotometer. Risk of migraine in lightly pigmented adults was elevated. Individuals with a low melanin index had over 3-fold increased risk of migraine (women: OR 3.53, men: OR 3.73). Fair phototype, which results from lightly pigmented skin, was associated with migraine prevalence. Migraineurs should take extra care to protect their skin from the negative effects of solar radiation.

Association of prenatal sex steroid exposure estimated by the digit ratio (2D:4D) with birth weight, BMI and muscle strength in 6- to 13-year-old Polish children.

OBJECTIVES: The aim of this paper was to provide evidence for the impact of prenatal sex steroid exposure on prenatal and postnatal body size parameters, and muscle strength in children. METHODS: The following anthropometric data were studied in a group of 1148 children (536 boys and 612 girls) aged 6-13 years: the 2D:4D digit ratio, birth weight and length, and birth head and chest circumference. Postnatal parameters (6-13 years) included body weight and height, BMI, waist and hip circumference, WHR, as well as grip strength in both hands. All parameters that required it were adjusted for sex and gestational or chronological age. A general linear model, Pearson's correlation, t-statistics and Cohen's Δ were used in statistical analysis. RESULTS: Among birth size parameters, only birth weight was significantly negatively correlated with the 2D:4D digit ratio in children. Higher (feminized) digit ratios were significantly correlated with postnatal parameters such as body weight, BMI, and waist and hip circumference (positively), as well as hand grip strength-a proxy for muscular strength (negatively). CONCLUSION: Problems with maintaining adequate body size parameters and muscle strength may be programmed in fetal life and predicted on the basis of the 2D:4D digit ratio. Body weight at birth and in early ontogenesis are additive correlates of the 2D:4D ratio. The present findings suggest that the 2D:4D digit ratio is related to postnatal phenotypes such as birth weight, overweight, and obesity as well as muscle strength in 6-13-year-old children of both sexes.

Prenatal oestrogen-testosterone balance as a risk factor of migraine in adults.

BACKGROUND: Migraine is a common neurological disease with extremely debilitating, but fully reversible symptoms. Women suffer from migraine more often than men. It was assumed that fluctuation of oestrogen level during menstrual cycle is one of many factors responsible for more frequent migraine attacks. The second-to-fourth digit ratio (2D:4D) is considered as an indicator of prenatal sex steroids. Balance of prenatal androgens (testosterone) and oestrogen has been studied in numerous diseases that are affected by hormones. However, the relationship between migraine and the sex steroids balance in prenatal development is still unexplained. The aim of this paper is to provide an evidence of relationship between prenatal oestrogen and testosterone exposure following 2D:4D digit ratio, and migraine prevalence in adults. METHODS: We examined a group of 151 adults (33 males, 118 females) with migraine and a control group of 111 adults (45 males, 66 females). 2D:4D digit ratio of both hands was measured using sliding Vernier calliper. RESULTS: Significant differences were found in the right hand. Female migraineurs had lower value of 2D:4D ratio than the control group and the right 2D:4D was lower than left 2D:4D (Δ2D:4D), suggesting prenatal testosterone dominance. The opposite relationship was observed in males. Male migraineurs had higher value of 2D:4D ratio and Δ2D:4D was greater than the control group, suggesting prenatal oestrogen dominance. CONCLUSIONS: Our results suggest that depending on sex, different proportion of prenatal sex steroids might be a risk factor of migraine in adults. Women with migraine were presumably exposed in prenatal life to higher testosterone levels relative to oestrogen, while men with migraine were probably exposed in prenatal life to higher levels of oestrogen relative to testosterone.

Thyroid diseases and second to fourth digit ratio in Polish adults.

The association between second to fourth finger ratio and thyroid diseases is unexplained. There is a possible interaction between prenatal exposition to sex hormone and thyroid functions in the adulthood. The study included 175 adults investigated in Lódz in the central Poland. It consisted of two main parts: a survey including questions about occurrence of thyroid gland dysfunction and anthropometric measurements (body mass and height and length of the second and fourth finger, waist and hip circumferences). The women who had thyroid disease had higher 2D:4D digit ratio (left hand) (mean = 1.004; SD = 0.036) than healthy ones (mean = 0.989; SD = 0.030) (t = - 2105; p = 0.038; d = 0.707). The association between thyroid diseases occurrence and prenatal steroid hormone exposition is noticed. Only females who had thyroid diseases tend to have higher 2D:4D digit ratio, for left hand.