Creatine kinase in relation to body fat in a Caucasian overweight and obese population

Creatine kinase serum levels in children revisited: New reference intervals from a large cohort of healthy children and adolescents

BACKGROUND

Creatine Kinase (CK) has become increasingly important in pediatrics as a commonly used laboratory screening parameter for neuromuscular diseases. Recent research suggests that hyperCKemia in children is not always associated with pathology and can occur due to several reasons. Little is known of various clinical factors that may influence CK throughout child development.

OBJECTIVE

This study aimed to establish reliable age- and sex-specific reference ranges for serum CK levels in healthy infants, children, and adolescents. In addition, the effect of puberty, oral contraceptive (OC) use as well as steroid hormones on CK was examined.

MATERIALS AND METHODS

The data was collected from subjects of the longitudinal population-based "LIFE Child"-cohort between 2011 and 2016 in Leipzig, Germany. 5238 blood samples of 2707 healthy children, aged between 0.14 months and 18 years, were analyzed.

RESULTS

Serum CK levels raised during the first year of life, peaking shortly after age one (P50girls = 2.7 µkat/L, P50boys = 2.90 µkat/L). There was a pronounced difference in the 97.5th percentile between boys and girls during adolescence with its maximum at age 18 (P97.5girls = 5.74 µkat/L, P97.5boys= 14.48 µkat/L). Also, mean CK serum levels were significantly higher in boys (bboys = 0.29, pboys < 0.001). Intake of oral contraceptives (OC), extreme underweight, underweight and obesity revealed a significant inverse correlation with CK serum levels.

CONCLUSION

Age, sex, OC intake and weight status affect serum CK levels, particularly during infancy and puberty. We recommend the use of age- and sex-specific reference values for CK serum levels to assess the clinical relevance of measurements.

Weight-bearing exercise prevents skeletal muscle atrophy in ovariectomized rats

Skeletal muscle atrophy (SMA) is a dominant symptom induced by estrogen deficiency which can lead to severe health problems of postmenopausal women. Furthermore, estrogen deficiency has severely compromised the maintenance of muscle stem cells as well as impairs self-renewal and differentiation into muscle fibers. Resistance training is commonly considered as a positive and useful intervention in accelerating the rate of muscle growth. As one of the resistance training, whether the weight-bearing exercise can alleviate SMA induced by estrogen deficiency has not been investigated. The rats were divided into 3 groups randomly: sham group, ovariectomized (OVX) group, and weight-bearing exercise (WBE) therapeutic group. The weight that rats were loaded was 35% of their body weight, and the rats were trained by treadmill training (5° slope, 20 m/min, 30 min/day, 6 days/week) for 8 weeks. After training, the quality and strength of skeletal muscle of the WBE rats were improved; meanwhile, the cross-sectional areas of the skeletal muscle were also increased. Moreover, the WBE activated Akt significantly, upregulated the expression of mTOR, and downregulated the expression of MSTN and its receptor ActRIIB and FoxO1, respectively. The SMA phenomena of rats which induced by estrogen deficiency were prevented effectively via WBE, and the MSTN/Akt/mTOR and FoxO1 signaling pathway may be the predominant way in this improvement.

Alanine Aminotransferase and Body Composition in Obese Men and Women

There is a known relationship between serum alanine aminotransferase (ALT) and obesity in humans, but the mechanism(s) are not clarified. This study investigated the associations between serum ALT and body composition in an overweight and obese population. The results are based on data from a previous randomized controlled trial treating obesity with vitamin D₃. A sample of 448 overweight and obese individuals underwent dual-energy X-ray absorptiometry (DEXA) and measured serum ALT along with supplementary blood samples at study baseline. Body fat mass and lean mass indexes were calculated by dividing total body fat/lean weight (kg) by body height squared (kg/m²). ALT correlated with body mass index (BMI) in men but not women (r = 0.33, P < 0.0001 vs. r = 0.06, P = 0.29). In men, serum ALT correlated positively with fat mass index (r = 0.23, P = 0.004) and lean mass index (r = 0.32, P < 0.0001). In women, ALT correlated with lean mass index (r = 0.13, P = 0.031) but not fat mass index (r = 0.003, P = 0.96). In a multivariate model adjusted for age and fat mass index, a 1-unit increase in lean mass index associated with a 0.37 U/L higher ALT in the male subgroup (95% CI 0.024 to 0.040, P < 0.0001). In conclusion, serum ALT was associated with body fat mass index in men and with lean mass index in men and women in an overweight and obese population. The findings also demonstrate a gender difference in the role of fat.

High Body Mass Index Is Associated with the Extent of Muscle Damage after Eccentric Exercise

Purpose: The present study aimed to investigate the effects of body mass index (BMI), which is an obesity index, on the change in the muscle damage index after eccentric exercise. Methods: Forty healthy male university students participated in this study and were classified into normal (BMI 18.5⁻22.9 kg/m², n = 20) and high BMI groups (BMI &ge; 25 kg/m², n = 20). For eccentric exercise, a modified preacher curl machine was used. Participants performed two exercise sets with 25 repetitions in each set. With regard to the muscle damage index, maximum strength, muscle soreness, and the creatine kinase (CK) level were measured. Results: Loss of maximum strength, muscle soreness, and the CK level were higher in the high BMI group than in the normal BMI group (p < 0.05, p < 0.05, and p < 0.01, respectively). Conclusions: In conclusion, BMI is one of the potential factors related to muscle damage after eccentric exercise.

Creatine kinase is associated with reduced inflammation in a general population: The Tromsø study

Background

Creatine kinase (CK) has been associated with reduced inflammation in obesity while inflammation is associated with obesity-related cardiovascular diseases. We investigated the relationship between CK and high sensitive C-reactive protein (hs-CRP) in a general population.

Methods

CK and hs-CRP were measured in the population-based Tromsø study that included entire birth cohorts and random samples of citizens between 30–87 years of age. The analyses were performed sex-stratified in 5969 men and 6827 women.

Results

CK correlated negatively with hs-CRP in men (r = -0.08, P <0.001) and women (r = -0.06, P <0.001). In univariable regression analyses, CK associated negatively with hs-CRP in men (ß = -0.14, 95% CI -0.19 to -0.10, P <0.001) and women (ß = -0.13, 95% CI -0.18 to -0.08, P <0.001). Mean CK declined from the 2. to the 4. quartiles of hs-CRP in both genders (P <0.001 for trends). There were positive correlations between CK and body mass index (BMI) in men (r = 0.10, P <0.001) and women (r = 0.07, P <0.001). Multiple regression analyses showed a 0.13 unit decrease in hs-CRP (mg/dl) per unit CK increase in men (95% CI -0.35 to -0.20) and 0.29 mg/dl in women (95% CI -0.36 to -0.21) when adjusted for age, BMI, lipids, s-glucose, s-creatinine, transaminases and coronary heart disease.

Conclusion

CK were inversely and independently associated with hs-CRP in a general population. These data provide evidence that CK might have anti-inflammatory properties, but the mechanism and clinical implications are unclarified.