Uncomplicated diabetes does not accelerate age-related sarcopenia

Isokinetic assessment of muscle function according to physical activity level and cardiovascular risk in asymptomatic adults aged 20 to 80 years

As limb muscle function is age- and sex-related, both elbow and knee isokinetic muscle functions and their main predictors, such as physical activity level and cardiovascular risk factors, should be determined. We aimed to describe the percentiles of normality of the isokinetic muscle function of the knee and elbow joints. Secondarily, we developed equations to predict muscle function in apparently healthy adults aged 20-80 years, including cardiovascular risk factors. We conducted a cross-sectional study with 1,334 adults. We collected sociodemographic data, self-reported cardiovascular risk, anthropometry, body composition (bioelectrical impedance), moderate-to-vigorous physical activity (MVPA) (triaxial accelerometry), and isokinetic muscle function. Multiple regression analysis was used to develop equations to predict isokinetic muscle function. Percentiles of normality for muscle function were described by sex and age (20-39, 40-59, and >60 years). The models accounted for 49.6-70.9% of the total variability of muscle function, but MVPA and cardiovascular risk slightly influenced the coefficient of determination (additional ΔR2=0.003-0.006). Demographic and anthropometric variables were more relevant predictors of isokinetic muscle function (R2=0.50-0.70) than MVPA and cardiovascular risk. Even though they correlated with muscle function, cardiovascular risk and MVPA failed to explain the variability of muscle function largely determined by anthropometric and sociodemographic data. The percentile values and equations developed will help in interpreting the isokinetic muscle function and improve its clinical use.

Foreign allometric exponents adequately normalize isokinetic knee extension strength to identify muscle weakness and mobility limitation in Portuguese older adults: a cross-sectional study

Background

Identifying muscle weakness is challenging, because the reduction of strength with aging does not depend only on sarcopenia, but also on sensorimotor deficits. Nevertheless, this identification is improved by adjusting muscle strength allometrically, by removing the influence of body size. However, the effectiveness of foreign models to normalize these (dys)functionalities is not yet tested. This study aimed to compare and apply foreign allometric exponents for normalizing isokinetic knee extension strength in Portuguese older adults to identify muscle weakness/mobility limitation. Additionally, to attest any populational difference, data of these people and Brazilian older adults were compared

Methods

This is a cross-sectional study encompassing 226 Portuguese (n = 132) and Brazilian (n = 94) older adults. Mobility limitation (six-minute walk test, at lowest quartile), lower limb strength (knee extension isokinetic strength at 60º/s), and body dimensions measures were taken. Foreign allometric exponents (^b) were used to normalize Portuguese strength (strength/body-size variables^b). Non-normalized and normalized strength were compared (ROC) to generate the most accurate cut-point for identifying muscle weakness/mobility limitation.

Results

Older Portuguese men and women had better mobility than their Brazilian counterparts. Older Portuguese women had superior muscle strength to Brazilian women. Normalization from 11 foreign models removed the influence of body size on muscle strength, with a negligible correlation (r ≤ 0.30). In contrast to the non-normalized strength, the normalized strength cut-off points were sufficiently accurate (AUC ≥ 0.70) to avoid identifying false-negative cases of weakness/mobility limitation.

Conclusions

Portuguese older women were stronger and had superior functional capacity compared to Brazilian ones. Normalized foreign models improved the accuracy in identifying muscle weakness/mobility limitation in Portuguese older adults. The isokinetic knee extension muscle strength normalized, even using foreign allometric exponents, should be better than no adjustment.

The evaluation of muscle strength and architecture in type 1 diabetes mellitus: a cross-sectional study

BACKGROUND

The aim of this study is to compare muscle strength and architecture between type 1 diabetes patients and healthy volunteers and to assess whether there is an ultrasonographic structural change in this population.

METHODS

Thirty-two patients with T1D (23 female, 9 male) with an age average of 31.3 ± 8.7 years, matched in terms of age, gender, height, weight and physical activity were included in the study. In the T1D and control group, ultrasonographic measurements of quadriceps femoris muscle (RF, VI, VM, VL) and pennate angle (VI, VM, VL) were performed. Muscle strength values were measured using isokinetic dynamometer system at angular velocities of 60º/s and 180º/s in both groups.

RESULTS

Initially, both groups were similar in demographic and clinical characteristics (p > 0.05). In the T1D group, there was a statistically significant difference in flexion/extension peak torque measurements at an angular velocity of 60º/s compared to the control group (p < 0.05). In support of these isokinetic measurements, RF, VI, VM, VL muscle thicknesses and VI, VM pennate angle measurements in T1Ds were significantly lower (p < 0.05). When the T1D group was subgrouped according to HbA1C and diabetes duration, there was no significant difference in ultrasonographic and isokinetic measurements between the two groups (p > 0.05). When the T1D group was subgrouped, in the group that used insulin pump RF, VI, VM muscle thickness measurements were significantly higher (p < 0.05) than the group using subcutaneous insulin.

CONCLUSIONS

This study supports that muscle strength and architecture are adversely affected in the T1D patient group, insulin deficiency is a risk factor for sarcopenia and this can be shown through ultrasonography. It can also be said that insulin pump use has more positive effects in terms of diabetic myopathy than subcutaneous insulin, and diabetic myopathy develops independently of other diabetic complications. As a result, the muscle architecture of T1D people is adversely affected by insulin deprivation, so regular physical activity should be an integral part of diabetes treatment.

Bioelectrical Impedance Analysis for the Assessment of Body Composition in Sarcopenia and Type 2 Diabetes

Sarcopenia is emerging as a severe complication in type 2 diabetes (T2DM). On the other hand, it has been documented that nutritional aspects, such as insufficient protein or total energy intake, increase sarcopenia risk. The analysis of body composition is a relevant approach to assess nutritional status, and different techniques are available. Among such techniques, bioelectrical impedance analysis (BIA) is particularly interesting, since it is non-invasive, simple, and less expensive than the other techniques. Therefore, we conducted a review study to analyze the studies using BIA for body composition analysis in T2DM patients with sarcopenia or at risk of catching it. Revised studies have provided important information concerning relationships between body composition parameters (mainly muscle mass) and other aspects of T2DM patients’ conditions, including different comorbidities, and information on how to avoid muscle mass deterioration. Such relevant findings suggest that BIA can be considered appropriate for body composition analysis in T2DM complicated by sarcopenia/muscle loss. The wide size of the patients’ cohort in many studies confirms that BIA is convenient for clinical applications. However, studies with a specific focus on the validation of BIA, in the peculiar population of patients with T2DM complicated by sarcopenia, should be considered.

Endothelin-1-mediated miR-let-7g-5p triggers interlukin-6 and TNF-α to cause myopathy and chronic adipose inflammation in elderly patients with diabetes mellitus

Background: Diabetes and sarcopenia are verified as mutual relationships, which seriously affect the quality of life of the elderly. Endothelin-1 is well investigated, is elevated in patients with diabetes, and is related to muscle cellular senescence and fibrosis. However, the mechanism of ET-1 between diabetes and myopathy is still unclear. The aim of this study was to evaluate the prevalence of sarcopenia in the elderly with diabetes and to clarify its relationship with ET-1 molecular biological mechanism, progress as well as changes in muscle and fat.

Methods: We recruited 157 type 2 diabetes patients over 55 years old and investigated the prevalence of sarcopenia in diabetes patients and examined the association of ET-1 alterations with HbA1c, creatinine, or AMS/ht2. Next, sought to determine how ET-1 regulates inflammation in muscle cells by western blot and qPCR assay. Using XF Seahorse Technology, we directly quantified mitochondrial bioenergetics in 3T3-L1 cells.

Results: ET-1 was positively correlated with HbA1c, creatinine levels, and duration of disease, and negatively correlated with AMS/ht2. We found that ET-1 dose-dependently induces tumor necrosis factor-α (TNF-α) and interleukin (IL)-6β expression through the PI3K/AKT, and NF-κB signaling pathways in C2C12 cells. Also identified that TNF-α, IL-6β, and visfatin releases were found in co-cultured with conditioned medium of ET-1/C2C12 in 3T3-L1 cells. ET-1 also reduces the energy metabolism of fat and induces micro-environment inflammation which causes myopathy. ET-1 also suppresses miR-let-7g-5p expression in myocytes and adipocytes.

Conclusion: We describe a new mechanism of ET-1 triggering chronic inflammation in patients with hyperglycemia.

Identification of muscle weakness in older adults from normalized upper and lower limbs strength: a cross-sectional study

BACKGROUND

To propose cut-off points for older adults' weakness for upper and lower limbs muscle strength normalized by body size with the ratio standard/muscle quality and allometric scaling.

METHODS

Ninety-four community-dwelling older adults (69.1% women) were assessed for 49 body-size variables (anthropometry, body composition and body indexes), handgrip strength (HGS), one maximum repetition measurement for knee extensors (1RM), isokinetic knee extension peak torque at 60°/s (PT), and six-minute walk test (6MWT). Ratio standard or muscle quality (muscle strength/body size) and allometric scaling (muscle strength/body sizeb; when b is the allometric exponent) were applied for body-size variables significantly correlated with HGS, 1RM and PT. Cut-off points were computed according to sex based on mobility limitation (6MWT < 400 m) with ROC curve and Youden index.

RESULTS

Absolute HGS, 1RM and PT cut-off points were not adequate because they were associated with body size (r > 0.30). But it was corrected with muscle strength normalization according to body size-variables: HGS (n = 1); 1RM (n = 24) and PT (n = 24). The best cut-off points, with the highest area under the curve (AUC), were found after normalization for men: HGS/forearm circumference (1.33 kg/cm, AUC = 0.74), 1RM/triceps skinfold (4.22 kg/mm, AUC = 0.81), and PT/body mass*height0.43 (13.0 Nm/kg*m0.43, AUC = 0.94); and for women: HGS/forearm circumference (1.04 kg/cm, AUC = 0.70), 1RM/body mass (0.54 kg/kg, AUC = 0.76); and PT/body mass0.72 (3.14 Nm/kg0.72; AUC = 0.82).

CONCLUSIONS

Upper and lower limbs muscle weakness cut-off points standardized according to body size were proposed for older adults of both sexes. Normalization removes the effect of extreme body size on muscle strength (both sexes) and improves the accuracy to identify weakness at population level (for women, but not in men), reducing the risk of false-negative/positive cases.

Sarcopenia with co-existent type 2 diabetes mellitus is associated with worse clinical outcomes among hospitalised cardiac patients

BACKGROUND & AIMS

Sarcopenia has been shown associated with functional decline, disability, poorer quality of life and mortality. However, there are limited studies among hospitalised cardiac patients in Malaysia. This study aimed to identify the association of sarcopenia and type 2 diabetes mellitus (T2DM) with clinical outcomes among hospitalised cardiac patients.

METHODS

This prospective observational study assessed 100 patients who were admitted to the general wards at the National Heart Institute. We measured handgrip strength, body composition using bioelectrical impedance analysis (BIA) and recorded the length of stay (LOS), unplanned readmission and incidence of infection within 90 days after discharge. Logistic regression analysis at a significant level p < 0.05 was used to identify the association between sarcopenia and clinical outcomes.

RESULTS

The prevalence of sarcopenia was 63%, and this was similar in patients with or without T2DM. After adjustment, sarcopenia was significantly associated with 90-day unplanned readmission (adjusted OR 3.5; 95%CI 1.40-8.77; p = 0.007) and LOS (AOR 0.4; 95%CI 0.16-0.88; p = 0.026). After adjustment, the co-existent of T2DM and sarcopenia was significantly associated with 90-day unplanned readmission (AOR 7.3; 95%CI 1.82-29.66; p = 0.005) and 90-day incidence of infection (AOR 4.4; 95%CI 1.12-17.52; p = 0.033).

CONCLUSION

Sarcopenia with co-existent T2DM was associated with increased risk for readmission and infection among hospitalised cardiac patients. Early identification of sarcopenia is important for timely intervention to improve prognosis in hospitalised cardiac patients with T2DM.

Low Protein Intakes and Poor Diet Quality Associate with Functional Limitations in US Adults with Diabetes: A 2005-2016 NHANES Analysis

Type 2 diabetes is associated with an increased risk for sarcopenia. Moreover, sarcopenia correlates with increased risk for falls, fractures, and mortality. This study aimed to explore relationships among nutrient intakes, diet quality, and functional limitations in a sample of adults across levels of glycemic control. Data were examined from 23,487 non-institutionalized adults, 31 years and older, from the 2005-2016 National Health and Nutrition Examination Survey. Hemoglobin A1c (%) was used to classify level of glycemic control: non-diabetes (<5.7%); pre-diabetes (5.7-6.4%); diabetes (≥6.5%). Dietary data were collected from a single 24-h dietary recall. Participants were categorized as meeting or below the protein recommendation of 0.8 g/kg of body weight. Physical functioning was assessed across 19-discrete physical tasks. Adults below the protein recommendation consumed significantly more carbohydrate and had lower diet quality across all glycemic groups compared to those who met the protein recommendation (p < 0.001). Adults with diabetes who did not meet protein recommendations had significantly poorer diet quality and significantly higher mean number of functional limitations. A greater percent of adults with diabetes who did not meet the protein recommendation reported being physically limited for most activities, with more than half (52%) reporting limitations for stooping, crouching, and kneeling. This study underscores the potential for physical limitations associated with low protein intakes, especially in adults with diabetes. In the longer term, low protein intakes may result in increased risk of muscle loss, as protein intake is a critical nutritional factor for prevention of sarcopenia, functional limitations, and falls.

Cut-off points of knee extension strength allometrically adjusted to identify sarcopenia risk in older adults: A cross-sectional study

PURPOSE

Handgrip strength used to identify sarcopenia is not representative of overall strength, especially as greater muscle volume and consequent autonomy-mobility are concentrated in the lower limbs. While absolute strength or relative to body mass is used to define sarcopenia, this relationship is not always linear. The aim of this study was to establish allometrically adjusted cut-off points of lower limb (quadriceps) muscle strength to identify sarcopenia risk in older adults.

METHODS

ninety-four physically independent individuals over the age of 60 were measured by DXA and sarcopenia was identified. The one-repetition maximum (1RM) test of knee extension strength was estimated using the extensor chair by the submaximal repetition protocol. The six-minute walk test performance was recorded. 1RM values were scaled by body mass (1RM/body mass) and allometrically adjusted (1RM/body mass^b). Cut-off points for sarcopenia from 1RM were defined with ROC curve and Youden index with functional limitation (walking distance<400 m). Analyzes considered sex (α = 5%).

RESULTS

Sarcopenia was present in 10.6 % of participants. The exponents ^b obtained were 0.70 for women and 0.96 for men. Except for absolute 1RM in women, all areas under the curve were acceptable (>0.70). The cut-off points for women and men were respectively, 38.1 and 56.1 kg for 1RM, 0.53 and 0.85 for 1RM/body mass, 1.48 and 1.00 for 1RM/body mass^b.

CONCLUSIONS

1RM of knee extension scaled by body mass or allometrically adjusted is an effective parameter to identify sarcopenia in older adults. The proposed cut-off points could be used to monitor sarcopenia risk in geriatrics.

Diabetes is associated with increased risks of low lean mass and slow gait speed when peripheral artery disease is present

AIMS

The aim of the current study was to evaluate the independent relationship of diabetes and PAD with lean mass and gait speed.

METHODS

This was a cross-sectional study of the U.S. population in 1999 through 2004, including 4769 participants aged ≥40 years of the National Health and Nutrition Examination Survey 1999-2004. Appendicular lean mass divided by body mass index (ALMBMI) and gait speed were analyzed. Low lean mass was defined as ALMBMI <0.512 in women and <0.789 in men, whereas mobility impairment was defined as gait speed <0.8m/s.

RESULTS

In the fully adjusted model, participants with both diabetes and PAD had a higher odds of low lean mass (OR=2.21; 95% CI: 1.07-4.57) and mobility impairment (OR=4.8; 95% CI: 1.93-11.97) when compared with participants with neither diabetes nor PAD. No significant association of "with diabetes without PAD" or "with PAD without diabetes" with low lean mass or mobility impairment was observed. Participants with diabetes and PAD had significantly lower ALMBMI and gait speed when compared with all other participants.

CONCLUSIONS

People with both diabetes and PAD had a higher likelihood of low lean mass and mobility impairment; such association was not observed in people with either diabetes or PAD alone.

Sarcopenia Is Associated with High Pulse Pressure in Older Women

Introduction. Sarcopenia is a geriatric syndrome associated with impairment of muscle function, metabolism, and cognition in older women. Recent studies have shown a relationship between changes in muscle mass and the cardiovascular system. However, this relationship has not been fully elucidated. Methods. One hundred and thirty community-dwelling Brazilian older women (65.4 ± 6.3 years) were recruited to participate in this study. Data on body composition (via bioelectrical impedance measurements), cardiovascular parameters (using an automatic and noninvasive monitor), and muscle function (using a 3-meter gait speed test) were measured. Results. Sarcopenic older women (n = 43) presented higher levels of pulse pressure (PP) (60.3 ± 2.6 mmHg) and lower muscle function (0.5 ± 0.0 m/s) compared with nonsarcopenic subjects (n = 87) (53.7 ± 1.5 mmHg; 0.9 ± 0.0 m/s) (P < 0.05). Linear regression analysis demonstrated a significantly negative association between skeletal muscle index (SMI) and PP levels (β = −226, P < 0.05). Furthermore, sarcopenic older women showed a 3.1-fold increased risk of having higher PP levels compared with nonsarcopenic women (IC = 1.323–7.506) (P < 0.05). Conclusion. Sarcopenic older women showed lower muscle function and higher cardiovascular risk due to increased PP levels compared with nonsarcopenic subjects.