Prediction and validation of total and regional skeletal muscle volume by using anthropometric measurements in prepubertal Japanese children.

It is difficult to easily estimate skeletal muscle (SM) volume in children. We aimed to develop regression-based prediction equations to estimate the total body and regional SM volume using calliper measurements of skinfold thickness and limb circumference and to investigate the validity of these equations. In total, 142 healthy, prepubertal, Japanese children, aged 6-12 years, were divided into two groups: the model development group (sixty boys, thirty-eight girls) and the validation group (twenty-six boys, eighteen girls). Contiguous magnetic resonance images were obtained from the first cervical vertebra to the ankle joints as reference data. SM volume was calculated from the summation of the digitised cross-sectional areas. Limb and waist circumferences were measured at mid-upper arm, mid-thigh, maximal calf and at the level of umbilicus. Each girth was corrected for subcutaneous adipose tissue thickness, as estimated by skinfold thickness measurements. Skinfold thickness was measured at the posterior upper arm, anterior thigh, medial calf and lateral to the umbilicus, using callipers. Significant correlations were observed between the site-matched SM volume, measured by MRI, and each corrected girth × standing height value in the model development group. When these SM volume prediction equations were applied to the validation group, the measured total body and regional SM volume were similar to the predicted values. These results suggest that the anthropometric prediction equations developed in this study provide reliable information about the total and regional SM volume in prepubertal Japanese children, with varying degrees of estimation accuracy for each region.

Coffee consumption and skeletal muscle mass: WASEDA'S Health Study.

Few studies have examined the association between coffee consumption and muscle mass; their results are conflicting. Therefore, we examined the association between coffee consumption and low muscle mass prevalence. We also performed an exploratory investigation of the potential effect modification by demographic, health status-related and physical activity-related covariates. This cross-sectional study included 2085 adults aged 40-87 years. The frequency of coffee consumption was assessed using a self-administered questionnaire. Muscle mass was assessed as appendicular skeletal muscle mass/height2 using a multifrequency bioelectrical impedance analyser. We defined low muscle mass using cut-offs recommended by the Asian Working Group for Sarcopenia. Multivariable-adjusted OR for low muscle mass prevalence were estimated using a logistic regression model. The prevalence of low muscle mass was 5·4 % (n 113). Compared with the lowest coffee consumption group (< 1 cup/week), the multivariable-adjusted OR (95 % CI) of low muscle mass prevalence were 0·62 (0·30, 1·29) for 1-3 cups/week, 0·53 (0·29, 0·96) for 4-6 cups/week or 1 cup/d and 0·28 (0·15, 0·53) for ≥ 2 cups/d (P for trend < 0·001). There were no significant interactions among the various covariates after Bonferroni correction. In conclusion, coffee consumption may be inversely associated with low muscle mass prevalence.

Relationship Between Muscle Deoxygenation and Cardiac Output in Subjects Without Attenuation of Deoxygenation Hemoglobin Concentration Near the End of Ramp Cycling Exercise: A Longitudinal Study.

The aim of this study was to investigate the longitudinal relationship between the slopes of systemic and quadriceps muscle O2 dynamics in subjects without attenuation point in deoxygenated hemoglobin concentration at vastus lateralis (APdeoxy-Hb@VL) during high-intensity cycling. Seven young men without APdeoxy-Hb@VL performed ramp cycling exercise until exhaustion before and after 8 weeks, while continuing recreational physical activities throughout that period. Muscle O2 saturation (SmO2) and deoxy-Hb were monitored at the vastus lateralis (VL) and rectus femoris (RF) by near infrared spectroscopy oximetry during exercise. Cardiac output (CO) was also continuously assessed. During high-intensity exercise, at VL, a significantly steeper slope of deoxy-Hb was found after 8 weeks compared with before, while the slopes of deoxy-Hb at RF were not significantly changed. Though a decrease in the slope of CO after 8 weeks did not reach significance (p = 0.12), the change in the slope of CO was significantly related to the change in the slopes of deoxy-Hb at VL (rs = -0.89, p < 0.01) and RF (rs = -0.86, p < 0.05). Our data reinforces the idea that, in subjects without APdeoxy-Hb@VL, the slope of muscle deoxygenation at VL during high-intensity cycling exercise may partly be explained by systemic O2 supply, rather than O2 balance in other thigh muscles.

Association between alcohol dietary pattern and prevalence of dyslipidaemia: WASEDA'S Health Study.

The association between a dietary pattern characterised by high alcohol intake and dyslipidaemia has not been fully investigated. Therefore, the present study aimed to investigate the association between alcohol dietary patterns and the prevalence of dyslipidaemia and its components. This cross-sectional study enrolled 2171 men and women aged ≥40 years who were alumni of a Japanese university. To identify dietary patterns, a principal component analysis was performed based on the energy-adjusted food intake estimated by a brief-type self-administered diet history questionnaire. Three dietary patterns were identified, the second of which was named the alcohol dietary pattern and was characterised by a high intake of alcoholic beverages, liver, chicken and fish. This alcohol dietary pattern was associated with reduced LDL-cholesterol levels. The fully adjusted OR (95 % CI) of high LDL-cholesterol for the lowest through highest quartile of alcohol dietary pattern score were 1·00 (reference), 0·83 (0·64, 1·08), 0·84 (0·64, 1·10) and 0·68 (0·49, 0·94), respectively. Subgroup analysis showed that the alcohol dietary pattern was inversely associated with the prevalence of dyslipidaemia in women, whereas it was positively associated with high TAG levels in men. In conclusion, the alcohol dietary pattern, characterised by a high intake of alcoholic beverages, liver, chicken and fish, was associated with the prevalence of dyslipidaemia and its components. This finding provides useful information for the prevention and treatment of dyslipidaemia by modifying the diet.

The combination of cardiorespiratory fitness and muscular fitness, and prevalence of diabetes mellitus in middle-aged and older men: WASEDA'S Health Study.

BACKGROUND: Although the negative relationship between cardiorespiratory fitness (CRF) or muscular fitness and diabetes mellitus were respectively observed in many previous studies, there is still a lack of studies that include CRF and muscular fitness simultaneously. Therefore, this study aimed to investigate the relationship between the combination of CRF and muscular fitness and diabetes through a cross-sectional study.  METHODS: This study was part of WASEDA'S Health Study, a cohort study launched in 2014. We used a part of the baseline data collected for this study. Maximal exercise test using a cycle ergometer and leg extension power (LEP) test were respectively used to evaluate CRF and muscular fitness. Since LEP is affected by body weight, relative LEP (rLEP) which is LEP per body weight, was used as an index of muscular fitness. 796 men (56.5 ± 10.4 years old) who completed a medical examination and fitness tests, were divided into two groups based on CRF and rLEP, respectively. The prevalence of diabetes was collected based on a self-reported questionnaire or blood test. Odds ratios and 95% confidence intervals (CIs) for the prevalence of diabetes were obtained using logistic regression models while adjusting for age, body mass index, exercise habits, family history of diabetes, smoking habits, and drinking habits. RESULTS: 55 (7%) participants had diabetes. Compared to participants with lower CRF or rLEP, the odds ratio (95% CIs) of diabetes in those with higher CRF or rLEP was 0.46 (0.21-0.98) or 0.34 (0.16-0.74), respectively. Furthermore, using the lower CRF and lower rLEP group as the reference, the odds ratio (95% CIs) for the lower CRF and higher rLEP group was 0.32 (0.12-0.88), and higher CRF and higher rLEP group was 0.21 (0.07-0.63), after adjusting for potential confounding factors. CONCLUSIONS: CRF and rLEP have independent and joint inverse associations with diabetes prevalence. In addition, participants with high CRF and high rLEP had a lower prevalence of diabetes compared to those with only high CRF or only high rLEP.

Systemic and Quadriceps Muscle O2 Dynamics in Subjects Without Attenuation Point of Deoxygenated Haemoglobin Concentration During Ramp Cycling Exercise.

The aim of this study was to compare systemic and quadriceps muscle O2 dynamics between aerobic capacity-matched subjects without (NAP; n = 5) and with (CON; n = 13) attenuation point in deoxygenated haemoglobin concentration (deoxy-Hb) at vastus lateralis (APdeoxy-Hb@VL) during ramp cycling exercise. Muscle O2 saturation (SmO2) and deoxy-Hb were monitored at the vastus lateralis (VL), rectus femoris (RF), and vastus medialis (VM) by spatial resolved near infrared spectroscopy during exercise. Cardiac output (CO) and pulmonary O2 uptake (VO2) were also continuously measured. During high-intensity exercise, in NAP, steeper slopes of both deoxy-Hb and SmO2 were found at VM, similar to VL muscle. Additionally, at RF, the slope of deoxy-Hb was steeper in NAP than CON. While the slope of pulmonary VO2 was similar between groups, the slope of CO was shallower in NAP than CON. During moderate intensity exercise, the slopes of all variables were similar between groups. These results suggest that the slope of muscle deoxygenation was enhanced not only in VL but also other thigh muscles in NAP, compared to CON. Because the slope of CO was associated with the slope of SmO2 and deoxy-Hb at VL during high-intensity exercise, the differences in subjects with and without APdeoxy-Hb@VL may be partly explained by systemic O2 supply, rather than O2 balance in the other quadriceps muscles.

Greater arterial wall viscosity in endurance-trained men.

PURPOSE: The age-associated increase in arterial wall viscosity (AWV) is attenuated by high cardiorespiratory fitness level. However, AWV in endurance-trained athletes have not been determined. We designed a cross sectional study to compare central AWV and compliance between endurance-trained young athletes and age-matched control men. METHODS: Twenty-one endurance-trained men (age 20.7 ± 0.3 years) and 20 age-matched healthy control men (age 21.6 ± 0.4 years) were studied. The common carotid artery was measured noninvasively by tonometry and automatic tracking of B-mode images to obtain instantaneous pressure and diameter hysteresis loops, and we calculated the dynamic carotid arterial compliance, static (effective and isobaric) compliance, and viscosity index. RESULTS: The AWV index in the endurance-trained men was larger than the control peers (2285 ± 181 vs. 1429 ± 124 mmHg·s/mm: P < 0.001). In addition, dynamic and static compliance were not statistically different between both groups. CONCLUSION: The present study indicated that the central AWV in endurance-trained athletes was greater than age-matched healthy control men. We believe that the AWV, as well as arterial compliance, is an important element for assessing vascular adaptation to endurance training.

Skeletal Muscle Deoxygenation and Its Relationship to Aerobic Capacity During Early and Late Stages of Aging.

The aim of this study was to compare muscle O2 dynamics during exercise among elderly (n = 10, age: 73 ± 3 years), middle-aged (n = 9, age: 50 ± 6 years), and young (n = 10, age: 25 ± 3 years) adults. The subjects performed ramp bicycle exercise until exhaustion. Muscle O2 saturation (SmO2) and relative changes from rest in oxygenated hemoglobin/myoglobin (∆oxy-Hb/Mb), deoxygenated hemoglobin/myoglobin (∆deoxy-Hb/Mb), and total hemoglobin concentration (∆total-Hb) were monitored continuously at the vastus lateralis muscle by near-infrared spatial resolved spectroscopy. At given absolute workloads, SmO2 and ∆oxy-Hb/Mb were significantly lower in elderly than the other groups, while ∆deoxy-Hb/Mb, ∆total-Hb, and pulmonary O2 uptake (VO2) were similar among the three groups. In contrast, there were no significant differences in muscle O2 dynamics during submaximal exercise between middle-aged and young subjects. Muscle O2 dynamics may be relatively preserved in early stages of aging, although muscle deoxygenation is enhanced in late stages of aging, probably due to reduced convective O2 supply. Moreover, change in SmO2 was significantly positively correlated with peak VO2 in the elderly, while a significant negative relationship was observed in middle-aged and young subjects. In late stages of aging, diminished peak VO2 may be caused by attenuated convective O2 transport, while reduced peak VO2 can be explained by lowered muscle O2 extraction in early stages of aging.

Differences in Muscle O2 Dynamics During Treadmill Exercise Between Aerobic Capacity-Matched Overweight and Normal-Weight Adults.

The aim of this study was to compare muscle O2 dynamics during exercise between aerobic capacity-matched overweight and normal-weight adults. Overweight women (OW, n = 9) and normal-weight women (NW, n = 14) performed graded treadmill exercise until exhaustion. Muscle O2 saturation (SmO2) and relative changes from rest in deoxygenated hemoglobin concentration (∆deoxy-Hb) and total hemoglobin concentration (∆total-Hb) were monitored continuously at gastrocnemius medialis muscle by near infrared spatial resolved spectroscopy. Significantly higher SmO2 and lower ∆deoxy-Hb and ∆total-Hb were observed in OW compared with NW. Pulmonary O2 uptake (VO2) normalized by fat-free mass was matched between groups. In both groups, peak VO2 was significantly correlated with change in SmO2 and ∆deoxy-Hb. Our findings suggest that both muscle blood volume and deoxygenation were lower in overweight adults, compared to aerobic capacity-matched normal-weight adults. Moreover, lowered muscle O2 extraction was related to peak VO2 in overweight adults, as well as in normal-weight adults.

The Relationship between Changes in Organ-Tissue Mass and Sleeping Energy Expenditure Following Weight Change in College Sumo Wrestlers.

Background and objectives: It has been well established that the resting energy expenditure (REE) for the whole body is the sum of the REE for each organ-tissue in young and middle-aged healthy adults. Based on these previous studies, although it is speculated that sleeping energy expenditure (SEE, which has small inter-individual variability) changes with a commensurate gain or reduction in the resting metabolic rate of each organ-tissue, it is unclear whether a change in organ-tissue masses is directly attributed to the fluctuation of SEE at present. This study aimed to assess the relationship between changes in organ-tissue mass and sleeping energy expenditure (SEE) following weight change in college Sumo wrestlers. This included blood analysis, which is related to energy expenditure. Materials and Methods: A total of 16 healthy male college Sumo wrestlers were recruited in this study. All measurements were obtained before and after weight change. Magnetic resonance imaging measurements were used to determine the volume of the skeletal muscle (SM), liver, and kidneys, and an indirect human calorimeter was used to determine SEE before and after weight change. Results: The change in body mass and SEE ranged between -8.7~9.5 kg, and -602~388 kcal/day. Moreover, changes in SM, liver, and kidneys ranged between -3.3~3.6 kg, -0.90~0.77 kg, and -0.12~0.07 kg. The change in SEE was not significantly correlated with the change in SM or liver mass, nor with blood analyses; however, a significant relationship between the change in kidney mass and SEE was observed. Conclusions: Based on our results, there is a possibility that the mass of the kidneys has an effect on the change in SEE following weight change in college Sumo wrestlers.

Physical activity and dietary intake among Chinese pregnant women: an observational study.

BACKGROUND: Physical activity (PA) and dietary intake are important modifiable factors associated with health outcomes. However, Chinese pregnant women's PA and dietary intake are only vaguely understood. The aim of this study was to reveal the characteristics of PA and dietary intake of Chinese women in different trimesters as well as the associations between PA and dietary intake. METHODS: This is a cross-sectional observational study. PA, dietary intake, and demographics of 1077 Chinese pregnant women were measured. The Chi-square test, Kruskal-Wallis test, multiple logistic regression, and multiple linear regression were used for data analysis. RESULTS: About 57.1% of the participants met the international guideline for PA. Household activity and occupational activity contributed the most to the total PA, while sports/exercise contributed little. The mean energy intake of the participants was 2008 ± 748.0 kcal. Most participants had normal energy intake, but they obtained excessive energy from fat (mean = 41.7 ± 8.7%). PA was not found to be significantly associated with dietary intake. Further, the participants who were unemployed during pregnancy (OR = 0.72, 95% CI: 0.55-0.95; p < 0.05) or had no exercise habits before pregnancy (OR = 0.62, 95% CI: 0.47-0.80; p < 0.01) were less likely to meet the PA guideline. The participants in the third trimester (OR = 1.43, 95% CI: 1.03-1.99; p < 0.05) were more likely to meet the PA guideline compared to those in the first trimester. The older participants (> 30 years) showed higher dietary intake than the younger (< 25 years) participants (p < 0.01). CONCLUSIONS: The total PA of Chinese women during pregnancy mostly consists of household and occupational activities, but little sports/exercise. Starting exercise before pregnancy may help women achieve adequate PA during pregnancy. Moreover, these women consumed an excessive amount of fat and their diet intake varies by age.

Lean Soft Tissue Mass Measured Using Dual-Energy X-Ray Absorptiometry Is an Effective Index for Assessing Change in Leg Skeletal Muscle Mass Following Exercise Training.

It is difficult to precisely and easily estimate the changes in skeletal muscle mass (SMM) following exercise training. We aimed to assess whether the change in lean soft tissue mass measured using dual-energy X-ray absorptiometry (DXA) reflects the change in SMM measured using magnetic resonance imaging (MRI) following exercise training in both the leg and trunk regions. Anthropometry, DXA, and MRI measurements of the trunk and leg regions were obtained in 10 male college sumo wrestlers before and after exercise training (mean duration between measurements: ~2 yr). Contiguous magnetic resonance images with 1-cm slice thickness and without gap were obtained from the first cervical vertebra to the ankle joints as reference data. Skeletal muscle volume was calculated from the summation of the digitized cross-sectional areas. The volume measurements were converted into mass by using an assumed skeletal muscle density (1.041 g/cm3). Trunk and leg areas, using DXA regional computer-generated lines, were adjusted to coincide with each discrete region by using MRI. Although the change in the DXA-measured lean soft tissue mass in the trunk region was significantly different from that of the MRI-measured SMM (Cohen's d = -1.3145, concordance correlation coefficient = 0.26, p < 0.01), the changes were similar in the leg region (Cohen's d = 0.07, concordance correlation coefficient = 0.87, p = 0.88). The exercise training-induced change in lean soft tissue mass significantly correlated with that in SMM, both in the leg (r = 0.88, p < 0.01) and trunk (r = 0.64, p < 0.05) regions. Bland-Altman analysis did not indicate a bias for the changes in leg lean soft tissue mass and SMM following exercise training. These results suggest that lean soft tissue mass measured using DXA is an effective index for assessing change in leg SMM following exercise training.

Effects of 8 Weeks' Training on Systemic and Muscle Oxygen Dynamics in University Rugby Players.

The aim of this study was to investigate the effects of 8 weeks of training on O2 dynamics in university rugby players. University rugby players (n = 15) participated in 5 strength training sessions and 4 field-based training sessions per week for 8 weeks. Before and after 8-weeks' training, the subjects performed ramp cycling exercise until exhaustion. Muscle O2 saturation (SmO2), relative changes from rest in deoxygenated hemoglobin concentration (∆Deoxy-Hb) and total hemoglobin concentration, cardiac output (CO), and pulmonary O2 uptake (VO2) were monitored continuously during exercise. Peak VO2 and CO were normalized by fat-free mass. Though peak VO2 tended to be increased after training, there were no significant changes in CO, nor any muscle O2 dynamic variables at peak exercise between before and after training. However, an increase in peak VO2 was significantly correlated with diminishment of deoxy-Hb and an increase in SmO2. Changes in CO caused by training were not related to improved peak VO2. The improvement of peak VO2 during 8 weeks of rugby training may have been caused by muscle O2 supply, rather than increased CO or muscle O2 extraction.

Diurnal variation in the diving bradycardia response in young men.

PURPOSE: The present study aimed to examine diurnal variation of the diving bradycardia responses on the same day. METHODS: Eighteen young men (age 26 ± 2 years; height 174.2 ± 6.0 cm; body mass 70.2 ± 8.1 kg; body fat 18.0 ± 3.8 %; mean ± standard deviation) participated in this study. Oral temperature, heart rate variability (HRV) from 5-min of electrocardiogram data, and diving bradycardia responses were measured at 0900, 1300, and 1700 hours daily. All participants performed diving reflex tests twice in the sitting position with the face immersed in cold water (1.9-3.1 °C) and apnea at midinspiration for a minimum of 30 s and as long as possible, in consecutive order. RESULTS: Oral temperature was found to be less in the morning (0900) than in the afternoon (1300) and evening (1700). In the frequency domain parameters of heart rate variability, the natural logarithms of high-frequency power were higher in the morning than in the evening. All participants showed bradycardia response to the two diving reflex tests. The peak values of R-R interval during the diving reflex test both for as long as possible and 30 s were longer in the morning than in the afternoon and evening. CONCLUSION: Our results indicated that the maximal bradycardia during the diving reflex test exhibits a diurnal variation, with peak levels at morning and gradual decrease towards the evening. The HRV indexes show the same variation.

Sex-Related Difference in Muscle Deoxygenation Responses Between Aerobic Capacity-Matched Elderly Men and Women.

Muscle O2 dynamics during ramp cycling exercise were compared between aerobic capacity-matched elderly men (n=8, age 65±2 years) and women (n=8, age 66±3 years). Muscle O2 saturation (SmO2) and relative change in deoxygenated (Δdeoxy-Hb) and total hemoglobin concentration (Δtotal-Hb) were monitored continuously during exercise in the vastus lateralis (VL) and gastrocnemius medialis (GM) by near infrared spatial resolved spectroscopy. SmO2 was significantly higher during exercise in women than in men in VL, but not in GM. In VL, Δdeoxy-Hb and Δtotal-Hb were significantly higher in men than in women, especially during high intensity exercise. However, no significant difference was observed in Δdeoxy-Hb or Δtotal-Hb in GM. Sex-related differences in muscle deoxygenation response may be heterogeneous among leg muscles in elderly subjects.

Reliability and Validity of a Chinese-Translated Version of a Pregnancy Physical Activity Questionnaire.

Objectives The objectives of the present study were to translate the English version of the Pregnancy Physical Activity Questionnaire into Chinese (PPAQ-C) and to determine its reliability and validity for use by pregnant Chinese women. Methods The study included 224 pregnant women during their first, second, or third trimesters of pregnancy who completed the PPAQ-C on their first visit and wore a uniaxial accelerometer (Lifecorder; Suzuken Co. Ltd) for 7 days. One week after the first visit, we collected the data from the uniaxial accelerometer records, and the women were asked to complete the PPAQ-C again. Results We used intraclass correlation coefficients to determine the reliability of the PPAQ-C. The intraclass correlation coefficients were 0.77 for total activity (light and above), 0.76 for sedentary activity, 0.75 for light activity, 0.59 for moderate activity, and 0.28 for vigorous activity. The intraclass correlation coefficients were 0.74 for "household and caregiving", 0.75 for "occupational" activities, and 0.34 for "sports/exercise". Validity between the PPAQ-C and accelerometer data was determined by Spearman correlation coefficients. Although there were no significant correlations for moderate activity (r = 0.19, P > 0.05) or vigorous activity (r = 0.15, P > 0.05), there were significant correlations for total activity [light and above; r = 0.35, P < 0.01)] and for light activity (r = 0.33, P < 0.01). Conclusions for Practice The PPAQ-C is reliable and moderately accurate for measuring physical activity in pregnant Chinese women.

Effects of Different Intensities of Endurance Exercise in Morning and Evening on the Lipid Metabolism Response.

To study the effects of different exercise intensity performed at different exercise times on lipid metabolism response during prolonged exercise. Nine young men performed endurance exercise at different exercise intensities (60%VO2max or Fatmax) in the morning (9 am to 10 am) or evening (5 pm to 6 pm); blood samples were collected before exercise and immediately and one and two hours after exercise completion. Expired gas was analyzed from the start of exercise until two hours after exercise completion. There were no significant changes in catecholamine (adrenaline and noradrenaline) and free fatty acid levels between morning and evening trials for each endurance exercise intensity. However, the morning and evening trials both exhibited significantly higher lipid oxidation at Fatmax than that at 60%VO2max. These results suggest that exercise at Fatmax offers greater lipid oxidation than that at 60%VO2max, regardless of exercise timing.

Prediction and validation of total and regional skeletal muscle volume using B-mode ultrasonography in Japanese prepubertal children.

Very few effective field methods are available for accurate, non-invasive estimation of skeletal muscle volume (SMV) and mass in children. We aimed to develop regression-based prediction equations for SMV, using ultrasonography, in Japanese prepubertal children, and to assess the validity of these equations. In total, 145 healthy Japanese prepubertal children aged 6-12 years were randomly divided into two groups: the model development group (sixty boys, thirty-seven girls) and the validation group (twenty-nine boys, nineteen girls). Reference data in the form of contiguous MRI with 1-cm slice thickness were obtained from the first cervical vertebra to the ankle joints. The SMV was calculated by the summation of digitised cross-sectional areas. Muscle thickness was measured using B-mode ultrasonography at nine sites in different regions. In the model development group, strong, statistically significant correlations were observed between the site-matched SMV (total, arms, trunk, thigh and lower legs) measured by MRI and the muscle thickness×height measures obtained by ultrasonography, for both boys and girls. When these SMV prediction equations were applied to the validation groups, the measured total and regional SMV were also very similar to the values predicted for boys and girls, respectively. With the exception of the trunk region in girls, the Bland-Altman analysis for the validation group did not indicate any bias for either boys or girls. These results suggest that ultrasonography-derived prediction equations for boys and girls are useful for the estimation of total and regional SMV.

Polygenic risk for hypertriglyceridemia is attenuated in Japanese men with high fitness levels.

High cardiorespiratory fitness (CRF) is associated with a reduced risk for dyslipidemia; however, blood lipid levels are also affected by individual genetic variations. We performed a cross-sectional study to determine whether CRF modifies polygenic risk for dyslipidemia. Serum levels of triglycerides (TG), LDL cholesterol (LDL-C), and HDL cholesterol (HDL-C) were measured in 170 Japanese men (age 20-79 yr). CRF was assessed by measuring maximal oxygen uptake (Vo2max), and subjects were divided into low-fitness and high-fitness groups according to the reference Vo2max value for health promotion in Japan. We analyzed 19 single nucleotide polymorphisms (SNPs) associated with TG, LDL-C, or HDL-C levels. Based on these SNPs, we calculated three genetic risk scores (GRSs: TG-GRS, LDL-GRS, and HDL-GRS), and subjects were divided into low, middle, and high groups according to the tertile for each GRS. Serum TG levels of low-fitness individuals were higher in the high and middle TG-GRS groups than in the low TG-GRS group (P < 0.01 and P < 0.05, respectively), whereas no differences were detected in the TG levels of high-fitness individuals among the TG-GRS groups. In contrast, the high LDL-GRS group had higher LDL-C levels than did the low LDL-GRS group, and HDL-C levels were lower in the high HDL-GRS group than in the low HDL-GRS group regardless of the fitness level (P < 0.05). These results suggest that high CRF attenuates polygenic risk for hypertriglyceridemia; however, high CRF may not modify the polygenic risk associated with high LDL-C and low HDL-C levels in Japanese men.

High cardiorespiratory fitness can reduce glycated hemoglobin levels regardless of polygenic risk for Type 2 diabetes mellitus in nondiabetic Japanese men.

High cardiorespiratory fitness (CRF) is associated with a reduced risk of Type 2 diabetes mellitus (T2DM) and improved ß-cell function; genetic factors also determine these risks. This cross-sectional study investigated whether CRF modifies the association of polygenic risk of T2DM with glucose metabolism in nondiabetic Japanese men. Fasting plasma glucose, insulin, and glycated hemoglobin (HbA1c) levels were measured in 174 Japanese men (age: 20-79 yr). ß-Cell function and insulin resistance were evaluated by calculating HOMA-ß and HOMA-IR, respectively. CRF was assessed by measuring maximal oxygen uptake (V̇o2max). Subjects were divided into the low and high CRF groups within each age group according to the median V̇o2max. Eleven single nucleotide polymorphisms (SNPs) associated with T2DM were analyzed and used to calculate genetic risk score (GRS); subjects were divided into the low, middle, and high GRS groups. The high GRS group had higher HbA1c levels than the low GRS group in both the low and high CRF groups (P < 0.05). Furthermore, the individuals with a high GRS had a lower HOMA-ß than those with a low GRS regardless of CRF (P < 0.05). In multiple linear regression analysis, although GRS was a significant predictor of HbA1c (ß = 0.153, P = 0.025), V̇o2max was also associated with HbA1c (ß = -0.240, P = 0.041) independent of GRS. These results suggest that CRF is associated with HbA1c levels independent of GRS derived from T2DM-related SNPs; however, it does not modify the association of GRS with increased HbA1c or impaired ß-cell function.