Adipocytokines and bone mineral density in adolescent female athletes

Relationship of visfatin with obesity and osteoporosis in patients with inflammatory bowel disease: a narrative review

Background

Inflammatory bowel disease (IBD) is an increasingly prevalent condition in developed countries. Alongside the growing number of patients, there is a rising incidence of disease-related complications, including osteoporosis. While well-established risk factors for low bone mineral density in IBD-such as low body mass or steroid therapy-are widely recognized, other contributing factors warrant further investigation. One such factor is visfatin, a proinflammatory adipokine encoded by the NAMPT gene.

Objectives

This review aimed to explore the association between visfatin level, bone health, and obesity among patients with inflammatory bowel disease.

Key findings

Although visfatin is primarily associated with metabolic syndrome, it may also influence bone mineral density by affecting osteoblast and osteoclast differentiation and function. Additionally, some studies have identified a correlation between visfatin levels and bone mineral density. A deeper understanding of visfatin's role in osteoporosis development may contribute to the identification of novel therapeutic strategies. Therefore, lower bone mineral density in inflammatory bowel disease may be associated with obesity and visfatin levels. However, visfatin concentrations depend on many factors, including genetics, immunology, and nutritional factors, which may affect visfatin levels.

Implications

Current research highlights visfatin as both a potential biomarker and a therapeutic target for osteoporosis treatment. Nevertheless, limited studies have specifically examined the relationship between visfatin and bone mineral density in IBD. Further research is required to clarify this association and to explore how variations in visfatin levels impact bone density in IBD patients.

High Serum Irisin Concentration Is Associated with More Disturbed Behavioural Eating Pattern in Adolescent Rhythmic Gymnasts

Background/Objectives: There are strict demands on body weight and shape in highly trained adolescent female athletes, and they are in the highest risk group for the development of eating disorders. This study aims to compare the behavioural eating patterns between highly trained female adolescent athletes and untrained controls (UCs), and to describe the associations between behavioural eating patterns and different energy homeostasis hormones. Methods: A total of 33 rhythmic gymnasts (RGs), 20 swimmers (SWs), and 20 UCs (n = 20) that were 14 to 18 years old participated in this investigation. Anthropometric measurements, body composition, training volume, 3-consecutive-day energy intake, and different energy homeostasis hormones were measured. For the evaluation of the individual behavioural eating pattern, an eating disorders assessment scale (EDAS) questionnaire with different subscales was used. Results: The mean EDAS subscale of restrained eating score was significantly higher in the RG group compared to the UC group (17.2 ± 7.4 vs. 11.5 ± 5.8; p < 0.05). The EDAS total score (r = 0.380) and the subscale score of preoccupation with body image and body weight (r = 0.371) were both positively correlated (p < 0.05) with serum irisin concentrations in the RG group. Conclusions: In conclusion, female rhythmic gymnasts reported a more often restrained eating pattern than untrained controls, and their more disturbed behavioural eating pattern was associated with a higher serum irisin concentration.

Associations of Serum Irisin and Fibroblast Growth Factor-21 Levels With Bone Mineral Characteristics in Eumenorrheic Adolescent Athletes With Different Training Activity Patterns

PURPOSE

To describe serum irisin and fibroblast growth factor-21 (FGF-21) concentrations in healthy female adolescents with different training activity patterns and their associations with bone mineral properties and metabolic markers.

METHODS

A total of 62 adolescent girls aged 14-18 years were recruited: 22 rhythmic gymnasts, 20 swimmers, and 20 untrained controls. Bone mineral characteristics by dual-energy X-ray absorptiometry, daily energy intake by dietary recall, serum irisin, FGF-21, undercarboxylated osteocalcin, and C-terminal telopeptide of type I collagen were measured in all girls.

RESULTS

Whole body and lumbar spine areal bone mineral density and lumbar spine bone mineral content were higher in the rhythmic gymnasts group compared with swimmers and untrained controls groups (P < .05). Serum irisin, FGF-21, undercarboxylated osteocalcin, and C-terminal telopeptide of type I collagen levels were not significantly different between the groups. In the rhythmic gymnasts group, serum FGF-21 concentration was positively correlated with lumbar spine areal bone mineral density independently of confounding factors (r = .51; P = .027).

CONCLUSIONS

Serum irisin and FGF-21 levels were not different between adolescent eumenorrheic girls with different training activity patterns. FGF-21 was positively associated with lumbar spine areal bone mineral density, which predominantly consists of trabecular bone in adolescent rhythmic gymnasts.

Does Swimming Exercise Impair Bone Health? A Systematic Review and Meta-Analysis Comparing the Evidence in Humans and Rodent Models

BACKGROUND

The effect of swimming on bone health remains unclear, namely due to discrepant findings between studies in humans and animal models.

OBJECTIVE

The aim of this systematic review and meta-analysis is to identify the available evidence on the effects of swimming on bone mass, geometry and microarchitecture at the lumbar spine, femur and tibia in both humans and rodent animal models.

METHODS

The study followed PRISMA guidelines and was registered at PROSPERO (CRD4202236347 and CRD42022363714 for human and animal studies). Two different systematic literature searches were conducted in PubMed, Scopus and Web of Science, retrieving 36 and 16 reports for humans and animal models, respectively.

RESULTS

In humans, areal bone mineral density (aBMD) was similar between swimmers and non-athletic controls at the lumbar spine, hip and femoral neck. Swimmers' tibia diaphysis showed a higher cross-sectional area but lower cortical thickness. Inconsistent findings at the femoral neck cortical thickness were found. Due to the small number of studies, trabecular microarchitecture in human swimmers was not assessed. In rodent models, aBMD was found to be lower at the tibia, but similar at the femur. Inconsistent findings in femur diaphysis cross-sectional area were observed. No differences in femur and tibia trabecular microarchitecture were found.

CONCLUSION

Swimming seems to affect bone health differently according to anatomical region. Studies in both humans and rodent models suggest that tibia cortical bone is negatively affected by swimming. There was no evidence of a negative effect of swimming on other bone regions, both in humans and animal models.

Follistatin Is Associated with Bone Mineral Density in Lean Adolescent Girls with Increased Physical Activity

Follistatin is a member of the activin-follistatin-inhibin hormonal system and is proposed to affect bone metabolism. However, data regarding the effect of follistatin on bone are relatively scarce and contradictory in humans. The purpose of the current study was to investigate possible associations of serum follistatin concentration with bone mineral characteristics in lean and physically active adolescent girls. Bone mineral density, body composition, resting energy expenditure and different energy homeostasis hormones in serum including follistatin, leptin and insulin were investigated. Significant relationships (p < 0.05) between serum follistatin (1275.1 ± 263.1 pg/mL) and whole-body (WB) bone mineral content (r = 0.33), WB areal bone mineral density (aBMD) (r = 0.23) and lumbar spine (LS) aBMD (r = 0.29) values were observed. Serum follistatin remained associated with LS aBMD independent of body fat and lean masses (r = 0.21; p < 0.05). However, the follistatin concentration explained only 3% (R² × 100; p = 0.049) of the total variance in LS aBMD values. In conclusion, serum follistatin concentrations were associated with bone mineral values in lean adolescent girls with increased physical activity. Follistatin was an independent predictor of lumbar spine areal bone mineral density, which predominantly consists of trabecular bone.

Changes in irisin, inflammatory cytokines and aerobic capacity in response to three weeks of supervised sprint interval training in older men

BACKGROUND

This study investigated the effects of supervised short-term sprint interval training (SIT) on circulating irisin, interleukin (IL)-6 and tumour necrosis factor (TNF)-α concentrations, and aerobic capacity and body composition values in healthy older men.

METHODS

Eleven older men (63±8 years; 178.0±5.5 cm; 82.7±8.6 kg; 22.7±3.7% body fat) underwent SIT (6 repetitions of 30 s all-out cycling bouts with 4 min active recovery after each bout) three days a week for three consecutive weeks. Body composition measured by dual-energy X-ray absorptiometry, aerobic capacity assessed by direct peak oxygen consumption (VO<inf>2peak</inf>) test and morning fasting blood samples were obtained before and after a 3-week SIT intervention.

RESULTS

Nine supervised SIT sessions moderately (effect size [ES] =0.65; P<0.05) increased irisin concentrations (from 135.40±28.73 to 154.20±47.09 ng.mL^-1) together with moderate decreases (P<0.05) in IL-6 (ES=0.89; from 1.26±0.44 to 0.87±0.44 pg.mL^-1) and TNF-α (ES=0.64; from 5.10±1.23 to 4.31±1.20 pg.mL^-1) levels in older men. In addition, increase in VO<inf>2peak</inf> was significant but small (ES=0.25; P<0.05; from 36.0±7.1 to 37.8±6.7 mL.min.^-1kg^-1), while no changes (P>0.05) in body composition variables were observed after a short-term SIT period.

CONCLUSIONS

A 3-week SIT intervention with only nine training sessions increased circulating irisin concentrations, improved inflammatory profile and aerobic capacity without changes in body composition in healthy older men. Accordingly, a short-term SIT programme is a time efficient alternative for traditional aerobic training to improve metabolic health and aerobic capacity in older adults.

Associations of Circulating Irisin and Fibroblast Growth Factor-21 Levels with Measures of Energy Homeostasis in Highly Trained Adolescent Rhythmic Gymnasts

The aim of this investigation was to determine the associations of serum irisin and fibroblast growth factor-21 (FGF-21) with the measures of energy homeostasis, training stress and other energy homeostasis hormones in highly trained adolescent rhythmic gymnasts (RG). Thirty-three RG and 20 untrained controls (UC) aged 14−18 years participated in this study. Body composition, resting energy expenditure (REE), peak oxygen consumption, and different energy homeostasis hormones in serum, including irisin, FGF-21, leptin, and resistin, were measured. Irisin and FGF-21 were not significantly different (p > 0.05) between RG and UC groups. In RG, serum irisin was positively associated with REE (r = 0.40; p = 0.021) and leptin (r = 0.60; p = 0.013), while serum FGF-21 was related to body fat mass (r = 0.46; p = 0.007) and leptin (r = 0.45; p = 0.009). Irisin was related to FGF-21, independent of age, body fat, and lean masses (r = 0.36; p = 0.049) in RG. In conclusion, serum irisin concentration was associated with energy expenditure and serum FGF-21 level with energy availability measures in lean adolescent athletes, while no relationships of irisin and FGF-21 with energy status measures were observed in lean nonathletic adolescents.

Effects of Different Types of Mechanical Loading on Trabecular Bone Microarchitecture in Rats

Mechanical loading is generally considered to have a positive impact on the skeleton; however, not all types of mechanical loading have the same beneficial effect. Many researchers have investigated which types of mechanical loading are more effective for improving bone mass and strength. Among the various mechanical loads, high-impact loading, such as jumping, appears to be more beneficial for bones than low-impact loadings such as walking, running, or swimming. Therefore, the different forms of mechanical loading exerted by running, swimming, and jumping exercises may have different effects on bone adaptations. However, little is known about the relationships between the types of mechanical loading and their effects on trabecular bone structure. The purpose of this article is to review the recent reports on the effects of treadmill running, jumping, and swimming on the trabecular bone microarchitecture in small animals. The effects of loading on trabecular bone architecture appear to differ among these different exercises, as several reports have shown that jumping increases the trabecular bone mass by thickening the trabeculae, whereas treadmill running and swimming add to the trabecular bone mass by increasing the trabecular number, rather than the thickness. This suggests that different types of exercise promote gains in trabecular bone mass through different architectural patterns in small animals.

Relationships of Bone Mineral Variables with Body Composition, Blood Hormones and Training Volume in Adolescent Female Athletes with Different Loading Patterns

The aim of this investigation was to determine the relationships of areal bone mineral density (aBMD) and content (BMC) with body composition, blood hormone and training load variables in adolescent female athletes with different loading patterns. The participants were 73 healthy adolescent females (14–18 years), who were divided into three groups: rhythmic gymnasts (RG; n = 33), swimmers (SW; n = 20) and untrained controls (UC; n = 20). Bone mineral and body compositional variables were measured by dual-energy X-ray absorptiometry, and insulin-like growth factor-1 (IGF-1), estradiol and leptin were analyzed from blood samples. In addition, aerobic performance was assessed by a peak oxygen consumption test. No differences (p > 0.05) in weekly training volume were observed between rhythmic gymnasts (17.6 ± 5.3 h/week) and swimmers (16.1 ± 6.9 h/week). Measured areal bone mineral density and bone mineral content values were higher in rhythmic gymnasts compared with other groups (p < 0.05), while no differences (p > 0.05) in measured bone mineral values were seen between swimmers and untrained control groups. Multiple regression models indicated that IGF-1 alone explained 14% of the total variance (R² × 100) in lumbar spine aBMD, while appendicular muscle mass and training volume together explained 37% of the total variance in femoral neck BMC in the rhythmic gymnast group only. In swimmers, age at menarche, estradiol and appendicular muscle mass together explained 68% of the total variance in lumbar spine BMC, while appendicular muscle mass was the only predictor and explained 19 to 53% of the total variance in measured bone mineral values in untrained controls. In conclusion, adolescent rhythmic gymnasts with specific weight-bearing athletic activity present higher areal bone mineral values in comparison with swimmers and untrained controls. Specific training volume together with appendicular muscle mass influenced cortical bone development at the femoral neck site of the skeleton in rhythmic gymnasts, while hormonal values influenced trabecular bone development at the lumbar spine site in both athletic groups with different loading patterns.

A Longitudinal Study of Bone Mineral Accrual during Growth in Competitive Premenarcheal Rhythmic Gymnasts

The purpose of this investigation was to study whether prolonged competitive rhythmic gymnastics training influenced bone mineral accrual in premenarcheal girls. Eighty-nine girls (45 rhythmic gymnasts [RG] and 44 untrained controls [UC]) between 7 and 9 years of age were recruited and measured annually for four years (not all participants were measured at every occasion). Dual energy x-ray absorptiometry was used to assess the development of whole body (WB), femoral neck (FN) and lumbar spine (LS) bone mineral content (BMC). In addition, body composition, blood adipokine and jumping performance characteristics were obtained. For longitudinal analyses, hierarchical mixed-effects models were constructed to predict differences in the development of WB, FN and LS BMC between RG and UC groups, while accounting for differences in body composition, blood adipokine and jumping performance values. It appeared that from 8 years of age, RG had lower (p < 0.05) fat mass and leptin values, and higher (p < 0.05) jumping performance measures in comparison with UC girls. Hierarchical mixed-effects models demonstrated that RG had 71.9 ± 12.0, 0.23 ± 0.11 and 1.39 ± 0.42 g more (p < 0.05) WB, FN and LS BMC, respectively, in comparison with UC girls. In addition, WB, FN and LS BMC increased more (p < 0.05) between 7 to 12 years of age in RG girls in comparison with UC. In conclusion, these findings suggest that the prolonged exposure to competitive rhythmic gymnastics trainings in premenarcheal girls is associated with greater bone mineral accrual despite lower body fat mass and leptin values.

Sclerostin, preadipocyte factor-1 and bone mineral values in eumenorrheic adolescent athletes with different training patterns

INTRODUCTION

The specific aims of the study were to compare possible differences in sclerostin and preadipocyte factor-1 (Pref-1) between rhythmic gymnasts (RG), swimmers (SW) and untrained controls (UC), and to investigate the relationships of sclerostin and Pref-1 with bone mineral characteristics in studied groups.

MATERIALS AND METHODS

This study included 62 eumenorrheic adolescents (RG = 22; SW = 20; UC = 20). Bone mineral and body composition characteristics were measured by dual-energy X-ray absorptiometry, and sclerostin, Pref-1, osteocalcin and C-terminal telopeptide of type I collagen (CTx) were measured.

RESULTS

Sclerostin was higher (P = 0.001) in RG (129.35 ± 51.01 pg/ml; by 74%) and SW (118.05 ± 40.05 pg/ml; by 59%) in comparison with UC (74.32 ± 45.41 pg/ml), while no differences (P = 0.896) were seen in Pref-1 (RG: 1.42 ± 0.16 ng/ml; SW: 1.41 ± 0.20 ng/ml; UC: 1.39 ± 0.26 ng/ml) between groups. Osteocalcin (RG: 7.74 ± 4.09 ng/ml; SW: 8.05 ± 4.18 ng/ml; UC: 7.04 ± 3.92 ng/ml; P = 0.843) and CTx (RG: 0.73 ± 0.22 ng/ml; SW: 0.64 ± 0.16 ng/ml; UC: 0.62 ± 0.20 ng/ml; P = 0.173) were not different between groups. Sclerostin correlated (P < 0.05) with whole-body bone mineral content (r = 0.61) and lumbar spine (LS) areal bone mineral density (aBMD) (r = 0.43) in RG, and femoral neck aBMD (r = 0.45) in UC. No correlation was found between sclerostin and bone mineral values in SW, and Pref-1 was not correlated with any bone mineral characteristics in studied groups. Sclerostin was the independent variable that explained 14% of the total variance (R² × 100) in LS aBMD value only in RG.

CONCLUSIONS

Adolescent athletes have higher sclerostin compared to UC. Sclerostin was correlated with bone mineral values and predicted areal bone mineral density in RG.

Basketball players possess a higher bone mineral density than matched non-athletes, swimming, soccer, and volleyball athletes: a systematic review and meta-analysis

Basketball athletes possess a higher bone mineral density (BMD) than matched non-athletes and swimming, soccer, and volleyball athletes. Differences appear to be exacerbated with continued training and competition beyond adolescence. The greater BMD in basketball athletes compared to non-athletes, swimming, and soccer athletes is more pronounced in males than females.

PURPOSE

The aim of this study was to examine differences in total and regional bone mineral density (BMD) between basketball athletes, non-athletes, and athletes competing in swimming, soccer, and volleyball, considering age and sex.

METHODS

PubMed, MEDLINE, ERIC, Google Scholar, and Science Direct were searched. Included studies consisted of basketball players and at least one group of non-athletes, swimming, soccer, or volleyball athletes. BMD data were meta-analyzed. Cohen's d effect sizes [95% confidence intervals (CI)] were interpreted as: trivial ≤ 0.20, small = 0.20-0.59, moderate = 0.60-1.19, large = 1.20-1.99, and very large ≥ 2.00.

RESULTS

Basketball athletes exhibited significantly (p < 0.05) higher BMD compared to non-athletes (small-moderate effect in total-body: d = 1.06, CI 0.55, 1.56; spine: d = 0.67, CI 0.40, 0.93; lumbar spine: d = 0.96, CI 0.57, 1.35; upper limbs: d = 0.70, CI 0.29, 1.10; lower limbs: d = 1.14, CI 0.60, 1.68; pelvis: d = 1.16, CI 0.05, 2.26; trunk: d = 1.00, CI 0.65, 1.35; and femoral neck: d = 0.57, CI 0.16, 0.99), swimming athletes (moderate-very large effect in total-body: d = 1.33, CI 0.59, 2.08; spine: d = 1.04, CI 0.60, 1.48; upper limbs: d = 1.19, CI 0.16, 2.22; lower limbs: d = 2.76, CI 1.45, 4.06; pelvis d = 1.72, CI 0.63, 2.81; and trunk: d = 1.61, CI 1.19, 2.04), soccer athletes (small effect in total-body: d = 0.58, CI 0.18, 0.97), and volleyball athletes (small effect in total-body: d = 0.32, CI 0.00, 0.65; and pelvis: d = 0.48, CI 0.07, 0.88). Differences in total and regional BMD between groups increased with age and appeared greater in males than in females.

CONCLUSION

Basketball athletes exhibit a greater BMD compared to non-athletes, as well as athletes involved in swimming, soccer, and volleyball.

Visfatin Connection: Present and Future in Osteoarthritis and Osteoporosis

Musculoskeletal pathologies (MSPs) such as osteoarthritis (OA) and osteoporosis (OP), are a set of disorders that cause severe pain, motion difficulties, and even permanent disability. In developed countries, the current incidence of MSPs reaches about one in four adults and keeps escalating as a consequence of aging and sedentarism. Interestingly, OA and OP have been closely related to similar risk factors, including aging, metabolic alterations, and inflammation. Visfatin, an adipokine with an inflammatory and catabolic profile, has been associated with several OA and OP metabolic risk factors, such as obesity, insulin resistance, and type II diabetes. Furthermore, visfatin has been associated with the innate immune receptor toll-like receptor 4 (TLR4), which plays a key role in cartilage and bone inflammatory and catabolic responses. Moreover, visfatin has been related to several OA and OP pathologic features. The aim of this work is to bring together basic and clinical data regarding the common role of visfatin in these pathologies and their major shared risk factors. Finally, we discuss the pitfalls of visfatin as a potential biomarker and therapeutic target in both pathologies.

Plasmatic adipocyte biomarkers and foot pain associated with flatfoot in schoolchildren with obesity

SUMMARY OBJECTIVE The aim of this study was to determine the potential association of foot pain and plasmatic adipocytes as physiological biomarkers of childhood obesity with the incidence of flatfoot in a cohort of Egyptian school children aged 6 -12 years. METHODS A total of 550 Egyptian schoolchildren (220 boys and 330 girls) aged 6-12 years were randomly invited to participate in this descriptive survey analysis. For all children, we assessed the diagnosis and severity of flatfoot as well as plasma adipocytes, as well as adiponectin, leptin, resistin, IL-6, and TNF-α, using the Dennis method and immunoassay techniques respectively. Foot pain was assessed by using a standard VAS of 100 mm and Faces Pain Scale, respectively. RESULTS Flat foot was predicted in 30.4% of school-age children, most of them showed a higher frequency of overweight (33.3%) and obesity (62.5%). Boys showed higher ranges of flat foot than girls. Foot pain significantly correlated with flat foot and obesity among the studied populations. In overweight-obese children, plasmatic adipocyte variables, as well as adiponectin, leptin, resistin, IL-6, TNF-α showed significant correlations with foot stance, especially in boys. Also, the studied adipocyte variables along with BMI, age, gender explained about~65% of the variance of flatfoot with pain among our school-age students. CONCLUSION Foot pain showed an association with flat foot and childhood obesity in 30.4% of school-age students (6-12 years). Foot pain was shown to correlate positively with the incidence of flat foot and changes in adiposity markers, as well as adiponectin, leptin, resistin, Il-6, TNF-α.

Physical Activity and Bone Health: What Is the Role of Immune System? A Narrative Review of the Third Way

Bone tissue can be seen as a physiological hub of several stimuli of different origin (e.g., dietary, endocrine, nervous, immune, skeletal muscle traction, biomechanical load). Their integration, at the bone level, results in: (i) changes in mineral and protein composition and microarchitecture and, consequently, in shape and strength; (ii) modulation of calcium and phosphorous release into the bloodstream, (iii) expression and release of hormones and mediators able to communicate the current bone status to the rest of the body. Different stimuli are able to act on either one or, as usual, more levels. Physical activity is the key stimulus for bone metabolism acting in two ways: through the biomechanical load which resolves into a direct stimulation of the segment(s) involved and through an indirect load mediated by muscle traction onto the bone, which is the main physiological stimulus for bone formation, and the endocrine stimulation which causes homeostatic adaptation. The third way, in which physical activity is able to modify bone functions, passes through the immune system. It is known that immune function is modulated by physical activity; however, two recent insights have shed new light on this modulation. The first relies on the discovery of inflammasomes, receptors/sensors of the innate immunity that regulate caspase-1 activation and are, hence, the tissue triggers of inflammation in response to infections and/or stressors. The second relies on the ability of certain tissues, and particularly skeletal muscle and adipose tissue, to synthesize and secrete mediators (namely, myokines and adipokines) able to affect, profoundly, the immune function. Physical activity is known to act on both these mechanisms and, hence, its effects on bone are also mediated by the immune system activation. Indeed, that immune system and bone are tightly connected and inflammation is pivotal in determining the bone metabolic status is well-known. The aim of this narrative review is to give a complete view of the exercise-dependent immune system-mediated effects on bone metabolism and function.

Bone Accrual in Children and Adolescent Nonelite Swimmers: A 2-Year Longitudinal Study

OBJECTIVE

To examine differences in bone mass between children and adolescents swimming competitively at nonelite levels (locally and regionally) and nonathletes and to assess changes in bone mass in these 2 groups over 24 months after taking into consideration several known confounders of bone mass.

DESIGN

Observational prospective study.

PARTICIPANTS

White nonelite swimmers (n = 128) and nonathletes (n = 106) 8 to 18 years of age from Memphis, Tennessee, USA.

MAIN OUTCOME MEASURES

Participants underwent dual-energy x-ray absorptiometry to assess total body and hip bone mineral content (BMC) at baseline and 12 and 24 months later.

RESULTS

At baseline, swimmers had 4.2% and 6.1% higher adjusted BMC for the total body and hip, respectively, compared with nonathletes (P values < 0.027). Averaging across assessment points, swimmers had 73.5 and 2.2 g higher BMC for the total body and hip, respectively, than nonathletes. Although there was a significant annual increase in total body and hip BMC in both groups (33.5 and 0.7 g, respectively), there was no difference in annualized bone accrual between swimmers and nonathletes for either total body BMC (swim by time effect; P = 0.213) or hip BMC (P = 0.265).

CONCLUSIONS

Competitive swimming at nonelite levels during childhood and adolescence does not seem to compromise bone accrual.

Total and regional bone mineral and tissue composition in female adolescent athletes: comparison between volleyball players and swimmers

Background

Exploring the osteogenic effect of different bone-loading sports is particular relevant to understand the interaction between skeletal muscle and bone health during growth. This study aimed to compare total and regional bone and soft-tissue composition between female adolescent swimmers (n=20, 15.71±0.93 years) and volleyball players (n=26, 16.20±0.77 years).

Methods

Dietary intake was obtained using food frequency questionnaires. Body size was given by stature, sitting height, and body mass. Six skinfolds were measured. Bone mineral content (BMC) and density (BMD), lean soft tissue, and fat tissue were assessed using dual-energy X-ray absorptiometry. Pearson’s product moment correlation coefficients were calculated to examine the relationships among variables, by type of sport. Comparisons between swimmers and volleyball players were performed using student t-tests for independent samples and multivariate analysis of covariance (controlling for age, training history and body size).

Results

Swimmers (BMC: 2328±338 g) and volleyball players (BMC: 2656±470 g) exceeded respectively by 2.1 and 2.8 standard deviation scores the average of international standards for whole body BMC of healthy adolescents. Years of training in swimmers were positively related to the upper limbs BMC (r=+0.49, p<0.05). In volleyball players, years of training correlated significantly with lower limbs BMD (r=+0.43, p<0.05). After adjustments for potential confounders, moderate differences (ES-r=0.32) between swimmers and volleyball players were noted in BMD at the lower limbs (volleyball players: +0.098 g∙cm^-2, +7.8%).

Conclusions

Youth female athletes who participate in high-intensity weight-loading activities such as volleyball exhibit moderately higher levels of BMD at the lower limbs compared to non-loading sports such as swimming.

Electronic supplementary material

The online version of this article (10.1186/s12887-018-1182-z) contains supplementary material, which is available to authorized users.

BONE MASS BY QUANTITATIVE ULTRASOUND OF FINGER PHALANGES IN YOUNG KARATE PRACTITIONERS

Objective:

To evaluate bone mass by quantitative ultrasound of the phalanges in young karate practitioners compared to a control group.

Methods:

Sample composed of 162 karate practitioners (52 females) and 326 healthy controls (110 females) aged 6 to 16 years old, in Western Paraná (Southern Brazil). Weight, height, BMI, amplitude-dependent speed of sound (AD-SoS) and bone transmission time (BTT) were evaluated. BMI, AD-SoS and BTT values were converted to Z scores. Mann-Whitney, chi-square or Fisher Exact tests and multiple linear regression were applied, with significance level set at p≤0.05.

Results:

Both genders showed higher values of BTT as Z scores when compared to control group. Females from the control group had higher AD-SoS values (m/s and Z score) compared to female karate practitioners. When relative and absolute frequencies were assessed according to BTT Z score in both groups, male karate practitioners’ bone mass was shown to be adequate more frequently. In female practitioners, age and weight were independent predictors of AD-SoS (R²=0.42) and BTT (R²=0.45), respectively. Among male karate practitioners, age was related to 26% of AD-SoS variances and height was responsible for 36% of BTT variances.

Conclusions:

Children and adolescents who practice karate were shown to have more bone mass in comparison to the control group, regardless of gender. BTT was more sensitive for this evaluation.

Novel bone metabolism-associated hormones: the importance of the pre-analytical phase for understanding their physiological roles

The endocrine function of bone is now a recognized feature of this tissue. Bone-derived hormones that modulate whole-body homeostasis, are being discovered as for the effects on bone of novel and classic hormones produced by other tissues become known. Often, however, the data regarding these last generation bone-derived or bone-targeting hormones do not give about a clear picture of their physiological roles or concentration ranges. A certain degree of uncertainty could stem from differences in the pre-analytical management of biological samples. The pre-analytical phase comprises a series of decisions and actions (i.e., choice of sample matrix, methods of collection, transportation, treatment and storage) preceding analysis. Errors arising in this phase will inevitably be carried over to the analytical phase where they can reduce the measurement accuracy, ultimately, leading discrepant results. While the pre-analytical phase is all important, in routine laboratory medicine, it is often not given due consideration in research and clinical trials. This is particularly true for novel molecules, such as the hormones regulating the endocrine function of bone. In this review we discuss the importance of the pre-analytical variables affecting the measurement of last generation bone-associated hormones and describe their, often debated and rarely clear physiological roles.

The Effect of Swimming During Childhood and Adolescence on Bone Mineral Density: A Systematic Review and Meta-Analysis

BACKGROUND

The effects of swimming on bone mineral density (BMD) have been studied by several researchers, with inconsistent results.

AIM

This meta-analysis aims to determine whether systematic swimming training may influence BMD during childhood and adolescence.

METHODS

A systematic search was performed in PubMed, SPORTDiscus and ClinicalTrials.gov from the earliest possible year to March 2015, with data extraction and quality assessment performed independently by two researchers following the PRISMA methodology. Swimmers were compared to sedentary controls and to athletes performing highly osteogenic sports. Therefore, a total of two meta-analyses were developed.

RESULTS

Fourteen studies met the inclusion criteria and were included in the meta-analyses. Swimmers presented similar BMD values to sedentary controls and lower than other high-impact athletes. Femoral neck and lumbar spine BMD differences between swimmers and sedentary controls and between swimmers and athletes practicing osteogenic sports appeared to increase with age and favored the non-swimming groups. There were no differences by sex.

CONCLUSION

While swimming is associated with several health benefits, it does not appear to be an effective sport for improving BMD. Swimmers might be in need of additional osteogenic exercises for increasing BMD values.

Implications of exercise-induced adipo-myokines in bone metabolism

Physical inactivity has been recognized, by the World Health Organization as the fourth cause of death (5.5 % worldwide). On the contrary, physical activity (PA) has been associated with improved quality of life and decreased risk of several diseases (i.e., stroke, hypertension, myocardial infarction, obesity, malignancies). Bone turnover is profoundly affected from PA both directly (load degree is the key determinant for BMD) and indirectly through the activation of several endocrine axes. Several molecules, secreted by muscle (myokines) and adipose tissues (adipokines) in response to exercise, are involved in the fine regulation of bone metabolism in response to the energy availability. Furthermore, bone regulates energy metabolism by communicating its energetic needs thanks to osteocalcin which acts on pancreatic β-cells and adipocytes. The beneficial effects of exercise on bone metabolism depends on the intermittent exposure to myokines (i.e., irisin, IL-6, LIF, IGF-I) which, instead, act as inflammatory/pro-resorptive mediators when chronically elevated; on the other hand, the reduction in the circulating levels of adipokines (i.e., leptin, visfatin, adiponectin, resistin) sustains these effects as well as improves the whole-body metabolic status. The aim of this review is to highlight the newest findings about the exercise-dependent regulation of these molecules and their role in the fine regulation of bone metabolism.

Swimming and bone: Is low bone mass due to hypogravity alone or does other physical activity influence it?

Swimming during adolescence has shown neutral or even negative effects on bone mass. Nevertheless, it is still unknown if these effects are due to swimming or to other factors, such as sedentary behaviors.

INTRODUCTION

Three objectives were described (1) to measure objective physical activity (PA) additional to swimming performed by adolescent swimmers (SWI) and compare it to that performed by normo-active controls (CG), (2) to describe the relationship between objectively measured PA and bone mass, and (3) to compare bone mass of swimmers that meet the World Health Organization PA guidelines (active) WHO and those that do not (inactive).

METHODS

A total of 71 SWI (33 females) and 41 CG (17 females) wore an accelerometer for at least 4 days. PA was expressed as the amount of time (minutes/day) in each intensity [sedentary/light/moderate or vigorous (VPA), and the sum of moderate and vigorous (MVPA)]. Using the cutoff points proposed by Vanhelst et al. SWI were classified as active or inactive according to whether they reached 60 min of weight-bearing MVPA per day or not. Bone mineral density (BMD) was measured by dual energy X-ray absorptiometry, and bone strength values were calculated with peripheral quantitative computed tomography. Differences in PA intensities were calculated between SWI and CG. The relation of VPA to bone mass was studied in the SWI.

RESULTS

Male-SWI spend less time in VPA and MVPA than male-GC, which partly explains the lower BMD values in SWI than CG.

CONCLUSION

Swimming may displace weight-bearing VPA with serious implications on bone health.

Swimming and cycling do not cause positive effects on bone mineral density: a systematic review

Osteoporosis is considered a common metabolic bone disease and its prevalence is increasing worldwide. In this context, physical activity has been used as a non-pharmacological tool for prevention and auxiliary treatment of this disease. The aim of this systematic review was to evaluate the effects of cycling and swimming practice on bone mineral density (BMD). This research was conducted in accordance with the recommendations outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The studies were consulted in the period from 2004 to 2014, through major electronic databases: PubMed(®), SciELO(®) and LILACS(®). Ten studies evaluated the effects of cycling on BMD, and the results showed that nine studies have linked the practice of professional cycling with low levels of BMD. Another 18 studies have reported that swimming has no positive effects on bone mass. We conclude that cycling and swimming do not cause positive effects on BMD; thus, these are not the most suitable exercises for prevention and treatment of osteoporosis.

Swimming and cycling do not cause positive effects on bone mineral density: a systematic review

Osteoporosis is considered a common metabolic bone disease and its prevalence is increasing worldwide. In this context, physical activity has been used as a non-pharmacological tool for prevention and auxiliary treatment of this disease. The aim of this systematic review was to evaluate the effects of cycling and swimming practice on bone mineral density (BMD). This research was conducted in accordance with the recommendations outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The studies were consulted in the period from 2004 to 2014, through major electronic databases: PubMed®, SciELO® and LILACS®. Ten studies evaluated the effects of cycling on BMD, and the results showed that nine studies have linked the practice of professional cycling with low levels of BMD. Another 18 studies have reported that swimming has no positive effects on bone mass. We conclude that cycling and swimming do not cause positive effects on BMD; thus, these are not the most suitable exercises for prevention and treatment of osteoporosis.

Adipocytokine and ghrelin levels in relation to bone mineral density in prepubertal rhythmic gymnasts entering puberty: a 3-year follow-up study

PURPOSE

To investigate changes in bone mineral density (BMD) in rhythmic gymnasts (RG) entering puberty and their age-matched untrained controls (UC) over the 36-month period, and associations with leptin, adiponectin and ghrelin over this period.

METHODS

Whole body (WB), lumbar spine (LS) and femoral neck (FN) BMD, WB bone mineral content (BMC), and leptin, adiponectin and ghrelin were measured in 35 RG and 33 UC girls at baseline and at 12-month intervals over the next 3 years. The change over the 36 months was calculated (∆ score).

RESULTS

The pubertal development over the next 36 months was slower in RG compard to UC, while there was no difference in bone age development between the groups. BMD at all sites was higher in RG in comparison with UC at every measurement point. ∆LS BMD and ∆FN BMD, but not ∆WB BMD and ∆WB BMC, were higher in RG compared with UC. None of the measured hormones at baseline or their ∆ scores correlated with ∆BMD and ∆BMC in RG. Baseline fat free mass correlated with ∆WB BMD and ∆WB BMC in RG, while baseline leptin was related to ∆WB BMC, ∆WB BMD and ∆LS BMD in UC.

CONCLUSIONS

Measured baseline hormones and their ∆ scores did not correlate with increases in bone mineral values in RG entering puberty. Although the pubertal development in RG was slower than in UC, high-intensity training appeared to increase BMD growth and counterbalance negative effects of slow pubertal develpment, lower fat mass and leptin in RG.

Effect of swimming exercise on three-dimensional trabecular bone microarchitecture in ovariectomized rats

Swimming is generally considered ineffective for increasing bone mass in humans, at least compared with weight-bearing sports. However, swimming exercise has sometimes been shown to have a strong positive effect on bone mass in small animals. This study investigated the effects of swimming on bone mass, strength, and microarchitecture in ovariectomized (OVX) rats. OVX or sham operations were performed on 18-wk-old female Fisher 344 rats. Rats were randomly divided into four groups: sham sedentary (Sham-CON), sham swimming exercised (Sham-SWI), OVX sedentary (OVX-CON), and OVX swimming exercised (OVX-SWI). Rats in exercise groups performed swimming in a water bath for 60 min/day, 5 days/wk, for 12 wk. Bone mineral density (BMD) in right femurs was analyzed using dual-energy X-ray absorptiometry. Three-dimensional trabecular architecture at the distal femoral metaphysis was analyzed using microcomputed tomography (μCT). Geometrical properties of diaphyseal cortical bone were evaluated in the midfemoral region using μCT. The biomechanical properties of femurs were analyzed using three-point bending. Femoral BMD was significantly decreased following ovariectomy. This change was suppressed by swimming. Trabecular bone thickness, number, and connectivity were decreased by ovariectomy, whereas structure model index (i.e., ratio of rod-like to plate-like trabeculae) increased. These changes were also suppressed by swimming exercise. Femurs displayed greater cortical width and maximum load in SWI groups than in CON groups. Together, these results demonstrate that swimming exercise drastically alleviated both OVX-induced decreases in bone mass and mechanical strength and the deterioration of trabecular microarchitecture in rat models of osteoporosis.

The effects of swimming training on bone tissue in adolescence

The aim was to analyze bone mineral content (BMC) and density (BMD) in regular swimming trained adolescents and the interaction that weigh-bearing sports may have on these values. Bone mass was evaluated by dual energy x-ray absorptiometry (DXA) and quantitative ultrasound (QUS) in 77 swimmers (34 females/43 males) and 52 normoactive controls (CG; 23 females/29 males) from 11 to 18 years. Swimmers who had performed or were performing other sports (OSP; 11 females/20 males) were compared with pure swimmers (PSW; 23 females/23 males). Both groups were compared with CG. Bone values were compared using analyses of covariance adjusting for height, calcium intake, subtotal lean (whole body lean minus head), and pubertal status. Male PSW showed lower BMD and BMC at several sites than male CG. However, for male OSP, only lumbar spine BMC was lower in OSP than male CG. Male PSW showed lower BMD and BMC when compared with male OSP. Female PSW showed higher arm BMD and lower leg BMC than female CG, while female OSP only presented lower leg BMC than female CG. Contrary to males, female-PSW presented higher BMD and BMC than female OSP. No differences in QUS values were found between swimmers and CG. To summarize, although more information is needed for females, it seems that for males, swimming is associated with lower BMC and BMD.

Endocrine disorders in adolescent and young female athletes: impact on growth, menstrual cycles, and bone mass acquisition

CONTEXT

Puberty is a crucial period of dramatic hormonal changes, accelerated growth, attainment of reproductive capacity, and acquisition of peak bone mass. Participation in recreational physical activity is widely acknowledged to provide significant health benefits in this period. Conversely, intense training imposes several constraints, such as training stress and maintenance of very low body fat to maximize performance. Adolescent female athletes are therefore at risk of overtraining and/or poor dietary intake, which may have several consequences for endocrine function. The "adaptive" changes in the hypothalamic-pituitary-gonadal, -adrenal, and somatotropic axes and the secretory role of the adipose tissue are reviewed, as are their effects on growth, menstrual cycles, and bone mass acquisition.

DESIGN

A systematic search on Medline between 1990 and 2013 was conducted using the following terms: "intense training," "physical activity," or "exercise" combined with "hormone," "endocrine," and "girls," "women," or "elite female athletes." All articles reporting on the endocrine changes related to intense training and their potential implications for growth, menstrual cycles, and bone mass acquisition were considered.

RESULTS AND CONCLUSION

Young female athletes present a high prevalence of menstrual disorders, including delayed menarche, oligomenorrhea, and amenorrhea, characterized by a high degree of variability according to the type of sport. Exercise-related reproductive dysfunction may have consequences for growth velocity and peak bone mass acquisition. Recent findings highlight the endocrine role of adipose tissue and energy balance in the regulation of homeostasis and reproductive function. A better understanding of the mechanisms whereby intense training affects the endocrine system may orient research to develop innovative strategies (ie, based on nutritional or pharmacological approaches and individualized modalities of training and competition) to improve the medical care of these adolescents and protect their reproductive function.

Bone metabolism and adipokines: are there perspectives for bone diseases drug discovery?

INTRODUCTION

Over the past 20 years, the idea that white adipose tissue (WAT) is simply an energy depot organ has been radically changed. Indeed, present understanding suggests WAT to be an endocrine organ capable of producing and secreting a wide variety of proteins termed adipokines. These adipokines appear to be relevant factors involved in a number of different functions, including metabolism, immune response, inflammation and bone metabolism.

AREAS COVERED

In this review, the authors focus on the effects of several adipose tissue-derived factors in bone pathophysiology. They also consider how the modification of the adipokine network could potentially lead to promising treatment options for bone diseases.

EXPERT OPINION

There are currently substantial developments being made in the understanding of the interplay between bone metabolism and the metabolic system. These insights could potentially lead to the development of new treatment strategies and interventions with the aim of successful outcomes in many people affected by bone disorders. Specifically, future research should look into the intimate mechanisms regulating peripheral and central activity of adipokines as it has potential for novel drug discovery.

Is bone tissue really affected by swimming? A systematic review

Background

Swimming, a sport practiced in hypogravity, has sometimes been associated with decreased bone mass.

Aim

This systematic review aims to summarize and update present knowledge about the effects of swimming on bone mass, structure and metabolism in order to ascertain the effects of this sport on bone tissue.

Methods

A literature search was conducted up to April 2013. A total of 64 studies focusing on swimmers bone mass, structure and metabolism met the inclusion criteria and were included in the review.

Results

It has been generally observed that swimmers present lower bone mineral density than athletes who practise high impact sports and similar values when compared to sedentary controls. However, swimmers have a higher bone turnover than controls resulting in a different structure which in turn results in higher resistance to fracture indexes. Nevertheless, swimming may become highly beneficial regarding bone mass in later stages of life.

Conclusion

Swimming does not seem to negatively affect bone mass, although it may not be one of the best sports to be practised in order to increase this parameter, due to the hypogravity and lack of impact characteristic of this sport. Most of the studies included in this review showed similar bone mineral density values in swimmers and sedentary controls. However, swimmers present a higher bone turnover than sedentary controls that may result in a stronger structure and consequently in a stronger bone.

Omentin-1, visfatin and adiponectin levels in relation to bone mineral density in Iranian postmenopausal women

The bone and fat interface is implicated in the pathogenesis of postmenopausal osteoporosis. The association between circulating omentin-1 levels and bone mineral density (BMD) in postmenopausal women has never been assessed. A total of 382 healthy postmenopausal women were randomly selected. Omentin-1, visfatin, adiponectin, the receptor activator of nuclear factor-κB ligand (RANKL), osteoprotegerin, high sensitivity C-reactive protein, degradation products of C-terminal telopeptides of type I collagen, and osteocalcin were measured by highly specific enzyme-linked immunosorbent assay methods. BMD was determined for the lumbar spine (L2-L4) and the proximal femur using dual-energy X-ray absorptiometry. In multivariable-adjusted linear regression, serum omentin-1 levels were inversely correlated with BMD at the lumbar spine (β=-0.11, p=0.020). In multiple regression analyses, serum visfatin and adiponectin levels were not significantly correlated with BMD at different skeletal sites after controlling for age, body mass index, and bone-related markers. However, the highest quartile of adiponectin compared to the lowest quartile, after adjusting for potential confounders, revealed an inverse association with BMD in the lumbar spine (β=-0.19, p=0.010). In conclusion, circulating omentin-1 levels had an inverse correlation with BMD at the lumbar spine in Iranian postmenopausal women. To further understand the role of omentin-1 in bone and mineral metabolism, large-scale longitudinal studies focusing on BMD and osteoporotic fractures are warranted.

High serum adiponectin predicts incident fractures in elderly men: Osteoporotic fractures in men (MrOS) Sweden

Adipocytes and osteoblasts share a common progenitor, and there is, therefore, potential for both autocrine and endocrine effects of adiponectin on skeletal metabolism. The aim of the present study was to determine whether high serum adiponectin was associated with an increased risk of fracture in elderly men. We studied the relationship between serum adiponectin and the risk of fracture in 999 elderly men drawn from the general population and recruited to the Osteoporotic Fractures in Men (MrOS) study in Gothenburg, Sweden. Baseline data included general health questionnaires, lifestyle questionnaires, body mass index (BMI), bone mineral density (BMD), serum adiponectin, osteocalcin, and leptin. Men were followed for up to 7.4 years (average, 5.2 years). Poisson regression was used to investigate the relationship between serum adiponectin, other risk variables and the time-to-event hazard function of fracture. Median levels of serum adiponectin at baseline were 10.4 µg/mL (interquartile range, 7.7-14.3). During follow-up, 150 men sustained one or more fractures. The risk of fracture increased in parallel with increasing serum adiponectin (hazard ratio [HR]/SD, 1.46; 95% confidence interval [CI], 1.23-1.72) and persisted after multivariate-adjusted analysis (HR/SD, 1.30; 95% CI, 1.09-1.55). Serum adiponectin shows graded stepwise association with a significant excess risk of fracture in elderly men that was independent of several other risk factors for fracture. Its measurement holds promise as a risk factor for fracture in men.

The effect of three-month pre-season preparatory period and short-term exercise on plasma leptin, adiponectin, visfatin, and ghrelin levels in young female handball and basketball players

OBJECTIVE

The aim of the study was to assess the effect of a 3-month pre-season preparatory period and shortterm moderate aerobic exercise and intensive fitness and speed exercise on adipokine and ghrelin levels in young female handball and basketball players.

MATERIALS AND METHODS

Fifty healthy young female professional basketball and handball players were enrolled into the study before the opening of the season (after a 2-month holiday with no training or dietary restrictions). Serum estradiol and plasma leptin, adiponectin, visfatin, and ghrelin levels were determined at the beginning and the end of a 3-month period of moderate aerobic training. Plasma adipokines and ghrelin levels were additionally assessed after 2 h of moderate aerobic exercise or after intensive fitness and speed exercise training.

RESULTS

Long-term moderate aerobic exercise was followed by a significant decrease in plasma ghrelin and leptin levels (921±300 vs 575±572 pg/ml, p<0.001 and 16.4±15.6 vs 11.8±16.3 ng/ml, p<0.01, respectively); plasma adiponectin and visfatin remained unchanged. No changes were observed in plasma ghrelin and leptin levels after short-term moderate aerobic exercise or after intensive fitness and speed exercise. Plasma visfatin concentration increased significantly after short-term moderate aerobic exercise (22.1±8.7 vs 27.6±9.0 ng/ml, p<0.001), whilst adiponectin increased after intensive fitness and speed exercise (16.7±7.8 vs 21.0±9.8 μg/ml, p<0.001).

CONCLUSIONS

Regular moderate aerobic training in preparation for the match season is followed by a decline in circulating leptin and ghrelin levels even in athletes without body weight changes. Short-term intensive fitness and moderate aerobic exercise seem to modulate the production of different adipokines.

Plasma adipocytokine and ghrelin levels in relation to bone mineral density in prepubertal rhythmic gymnasts

The aim of the present study was to investigate possible differences in plasma adipocytokine and ghrelin levels and body composition parameters in prepubertal rhythmic gymnasts (RG) and untrained controls (UC), and to examine the relationships of bone mineral density (BMD) with hormonal status in prepubertal children with different physical activity patterns. Eighty-nine 7- to 9-year-old girls participated in the study (RG, n = 46; UC, n = 43). Body composition and BMD were measured by dual-energy X-ray absorptiometry. Bone maturity was estimated by using a radiograph of the nondominant hand. The measured whole-body, lumbar spine (LS), and femoral neck (FN) BMD values were significantly higher (P < 0.05) in gymnasts than in controls. In addition, RG presented significantly lower and higher values (P < 0.05) for leptin and ghrelin concentrations, respectively, in comparison with UC. No differences were observed for adiponectin levels between the studied groups. No relationships between measured BMD values with leptin and ghrelin were observed even after adjustment for age and fat mass (FM) in RG. Whole-body and LS BMD values were significantly correlated with leptin after controlling for age and FM (r = 0.32, P < 0.05) in UC. Femoral neck BMD remained significantly correlated with ghrelin after adjusting for age and FM (r = -0.4, P < 0.05) in UC. No relationships were found between measured BMD values and adiponectin even after controlling for age and FM values in both groups. In conclusion, although all measured BMD values were significantly higher in RG, plasma adipocytokine and ghrelin concentrations were not directly related to bone mineralization in prepubertal RG in contrast to UC.

A common polymorphism rs3781637 in MTNR1B is associated with type 2 diabetes and lipids levels in Han Chinese individuals

Background

Several studies have shown that common variants in the MTNR1B gene were associated with fasting glucose level and type 2 diabetes. The purpose of this study was to examine whether tagging single nucleotide polymorphisms (SNPs) in the MTNR1B region were associated with type 2 diabetes and related traits in a Han Chinese population.

Methods

We investigated the association of polymorphisms in the MTNR1B gene with type 2 diabetes by employing a case-control study design (1118 cases and 1161 controls). Three tagging SNPs (rs10830963, rs3781637, and rs1562444) with R²>0.8 and minor allele frequency>0.05 across the region of the MTNR1B gene were studied. Genotyping was performed by matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy using a MassARRAY platform.

Results

The polymorphism rs3781637 was associated with type 2 diabetes adjusted for age, sex and body mass index (BMI) in the additive model and recessive model (OR = 1.22, 95% CI 1.01-1.46, p = 0.038 and OR = 2.81, 95% CI 1.28-6.17, p = 0.01, respectively). In the non-diabetic controls, rs3781637 was nominally associated with plasma triglyceride, total cholesterol and low density lipoprotein cholesterol (LDL-C) levels in the recessive model (p = 0.018, 0.008 and 0.038, respectively). After adjustment for multiple comparisons, the associations of rs3781637 with total cholesterol and LDL-C remained significant in the recessive model (the empirical p = 0.024 and 0.045, respectively), but the association between rs3781637 and triglyceride became non-significant (the empirical p = 0.095). The associations of rs10830963 and rs1562444 with type 2 diabetes and related traits were not significant in the additive, dominant and recessive models.

Conclusions

The rs3781637 A/G polymorphism of the MTNR1B gene is associated with type 2 diabetes, plasma, total cholesterol and LDL-C levels in the Han Chinese population.