Association between serum uric acid and muscle strength in older adults with or without gout diagnosis: NHANES 2011-2014

BACKGROUND & AIMS

Increased oxidative stress seems to be one of the causes of muscle strength loss during aging. Uric acid (UA) is an important antioxidant that has been positively associated with muscle strength in older adults. However, UA is also a prerequisite for gout, which is a type of arthritis that increases inflammation. The association between UA and muscle strength in individuals with gout is unknown. The aim of the study was to associate muscle strength with UA in older adults with or without gout diagnosis.

METHODS

The present study evaluated older adults aged from 60 to 80 years from National Health and Nutrition Examination Survey (NHANES) 2011-2012 and 2013-2014. A total of 2529 individuals (1249 men and 1280 women) were evaluated, with (n = 201) or without (n = 2328) gout diagnosis. Muscle strength was measured using a handgrip dynamometer. The combined grip strength (sum of highest values of both hands) was evaluated. Linear regression analysis was performed to evaluate the association between UA and strength adjusting for confounders.

RESULTS

Evaluating the individuals without gout, UA was positively associated with muscle strength [(β = 0.66 (CI = 0.08; 1.24); p = 0.028)]. However, this association was not significant in individuals with gout [(β = 0.20 (CI =  - 1.18; 1.58); p = 0.774)].

CONCLUSION

Serum UA is positively associated with handgrip strength only in older adults without gout diagnosis. These results suggest that the presence of gout may avoid a positive association between UA and muscle strength in older adults.

Serum uric acid is not associated with appendicular muscle mass index in young and middle-aged adults: Results from NHANES 2011-2012

BACKGROUND

Recent studies have evaluated the association between uric acid (UA) and muscle mass in older adults; however, little is known about this relationship in young and middle-aged individuals. Our aim was to investigate whether serum UA is associated with appendicular muscle mass index (AMMI) in young and middle-aged individuals. We also aimed to evaluate whether this association is sex-specific.

METHODS

A cross-sectional study was performed with young and middle-aged individuals aged from 20 to 59 years from National Health and Nutrition Examination Survey (NHANES) 2011-2012. A total of 2255 individuals (1440 young and 815 middle-aged individuals; 1167 men and 1088 women) were evaluated. Body composition was assessed by Dual Energy X-ray absorptiometry (DXA) and AMMI was calculated using the arms plus legs lean mass divided by the height squared. UA levels were measured by colorimetric method. Regression analyzes were performed to evaluate whether AMMI is associated with the tertiles of UA levels after adjustments for potential confounders.

RESULTS

In the unadjusted analyzes, serum UA was positively associated with AMMI for total sample, young, and middle-aged individuals of both sexes. However, after adjustments for confounders, UA levels were no longer associated with AMMI independent of the age-rage and sex.

CONCLUSION

Serum UA is not associated with AMMI in young or middle-aged individuals independent of the sex.

Serum uric acid is positively associated with muscle strength in older men and women: Findings from NHANES 1999-2002

BACKGROUND

One of the causes of strength loss in older adults is the increased oxidative stress; thus, substances with antioxidants properties may have protective effects on muscle strength. Uric acid (UA) is an important antioxidant and it seems to be positively associated with muscle strength in older adults; however, the current evidence is still limited.

AIM

To investigate whether serum UA is associated with muscle strength in older men and women.

METHODS

A cross-sectional study was performed evaluating older adults aged from 50 to 85 years from National Health and Nutrition Examination Survey (NHANES) 1999-2000 and 2001-2002. A total of 2361 individuals (1256 men and 1105 women) were evaluated. The peak isokinetic knee extensor strength was assessed by kinetic communicator isokinetic dynamometer; while UA levels were measured by colorimetric method. Linear regression analyses were performed to estimate the coefficients and 95% confidence intervals for muscle strength by quintiles of UA levels, adjusted for potential confounders.

RESULTS

In the unadjusted analyses, serum UA was positively associated with peak force in men and total sample, but not in women. However, after adjustments for confounders, UA levels were positively associated with peak force in total sample (p-trend = 0.007), men (p-trend = 0.044) and women (p-trend = 0.016).

CONCLUSION

Serum UA is positively associated with muscle strength in older men and women. These results suggest that UA levels seem to be a protective factor for muscle strength in older adults independent of the sex.

Serum Uric Acid Is Positively Associated with Muscle Mass and Strength, but Not with Functional Capacity, in Kidney Transplant Patients

Background: Our aim was to associate serum uric acid (UA) with muscle mass, strength and functional capacity in kidney transplant patients (KTPs). Methods: A cross-sectional study was performed on 113 KTPs. The fat-free mass and total and appendicular muscle mass were estimated by performing a bioelectrical impedance analysis. The strength was evaluated using the handgrip strength test (HGS) and the five times sit to stand test (5STS). The functional capacity was evaluated using the 4 m walk test and the short physical performance battery (SPPB). Results: Linear regression showed that the UA levels were positively associated with the muscle mass, fat-free mass, appendicular muscle mass, muscle mass index and appendicular muscle mass index. The 5STS results (seconds) were inversely associated with the UA levels, showing that individuals with higher UA were more likely to have more strength. However, UA was not associated with the HGS, 4 m walk test and SPPB results. Conclusion: UA levels were positively associated with muscle mass and strength, but not with functional capacity, in KTPs.

No Improvement in Running Time to Exhaustion at 100% VO2max in Recreationally Active Male Runners With a Preexercise Single-Carbohydrate Mouth Rinse

BACKGROUND

Carbohydrate (CHO) mouth rinse has been used as an ergogenic strategy due to its central effect; however, the effects of this intervention during short-duration high-intensity exercises are not fully understood.

PURPOSE

To investigate the effect of CHO mouth rinse on time to exhaustion in a short-duration high-intensity exercise performed on a treadmill.

METHODS

A randomized double-blind, placebo-controlled, crossover study was conducted with 10 (24.1 [4.3] y) recreationally active male runners. The protocol consisted of a warm-up at 65% of VO2max for 5 min followed by 3 min passive rest. At the end of this rest period, the individuals performed their mouth rinse either with CHO (maltodextrin, 6%) or with placebo (industrialized noncaloric juice with the same taste). Immediately after mouth rinse, the subjects ran at velocity equivalent to 100% of individual VO2max until voluntary exhaustion. The perceived effort was obtained through a Borg scale. Blood lactate was quantified before and after the protocol, and heart rate was evaluated during the protocol.

RESULTS

No difference was found (P = .90) in time to exhaustion between placebo (193.9 [46.5] s) and CHO mouth rinse (195.1 [51.8] s). Blood lactate, heart rate, and perception of effort increased in both groups, but with no differences (all variables, P > .05) between groups.

CONCLUSION

The findings showed that a preexercise single-CHO mouth rinse was ineffective to improve running time to exhaustion at velocity equivalent to 100% VO2max on a treadmill in recreationally active male runners.

Protein timing has no effect on lean mass, strength and functional capacity gains induced by resistance exercise in postmenopausal women: A randomized clinical trial

BACKGROUND & AIMS

Short-term studies have shown that protein intake immediately post-exercise increases muscle protein synthesis. However, the effect of protein timing (comparing protein intake post-exercise vs. several hours after exercise) on lean mass and strength gains in long-term studies is still not fully elucidated. Thus, the aim of our study was to evaluate the effect of protein timing on lean mass, strength and functional capacity gains induced by resistance exercise in postmenopausal women.

METHODS

Thirty-four postmenopausal women (60.9 ± 6.7 years) participated in this double-blind, parallel-group, randomized clinical trial. All individuals performed the same resistance training protocol in the morning, 3 times a week, at 70% of 1-maximum repetition (1-RM), over 8 weeks. Participants were randomly assigned to protein-carbohydrate group (PC) (n = 17), that ingested 30 g of whey protein immediately after exercise and 30 g of maltodextrin in the afternoon; and to carbohydrate-protein group (CP) (n = 17), that ingested 30 g of maltodextrin immediately after exercise and 30 g of whey protein in the afternoon. Lean mass was assessed using dual-energy X-ray absorptiometry, handgrip strength by a dynamometer, and strength was evaluated by 1-RM of bench press and leg extension. One mile walk test was performed to assess the functional capacity.

RESULTS

Both the PC group (37.3 [35.0-39.7] to 38.1 [35.9-40.5] kg) and the CP group (38.2 [36.0-40.5] to 38.8 [36.5-41.3] kg) increased the total lean mass (p < 0.001). An increase was also observed in both groups for 1-RM bench press, 1-RM leg extension and handgrip strength (p < 0.001). In addition, the time of 1-mile walk test decreased in both groups (p = 0.019). No differences were noted for group and time interaction for these variables (p > 0.05).

CONCLUSION

Protein timing has no effect on lean mass, strength and functional capacity gains induced by resistance exercise in postmenopausal women. This trial was registered at ClinicalTrials.gov as NCT03372876.

Isoflavone supplementation plus combined aerobic and resistance exercise do not change phase angle values in postmenopausal women: A randomized placebo-controlled clinical trial

OBJECTIVE

The aim of this study was to evaluate the effect of isoflavone supplementation plus combined exercise protocol on phase angle (PhA) values in postmenopausal women.

METHODS

Thirty postmenopausal women were randomly assigned in a double blind, placebo-controlled clinical trial divided into two groups: 100 mg/day of isoflavone supplementation (n = 16) and 100 mg/day of starch (placebo; n = 14). In addition, both groups performed a combined aerobic and resistance exercise during 10 weeks. Body composition and PhA were evaluated by bioelectrical impedance.

RESULTS

PhA values did not change in the isoflavone group (PRE: 6.7 ± 0.7° to POST: 6.7 ± 0.6°) and in the placebo group (PRE: 7.2 ± 1.0° to POST: 6.8 ± 0.5°); p group = 0.304, p time = 0.227, p group x time interaction = 0.137. Additionally, delta values were not different (0.04 ± 0.5° vs. -0.40 ± 0.99°; p = 0.176) between isoflavone and placebo groups, respectively.

CONCLUSION

We conclude that isoflavone supplementation plus combined aerobic and resistance exercise did not change PhA in postmenopausal women. The patients were part of ClinicalTrials.gov: NCT03008785.

Comparison of predictive equations of lean mass in young and postmenopausal women

BACKGROUND AND AIM

The lean mass (LM) is a predictor of functional capacity, quality of life, and mortality. In this way, the LM should be measured by reliable methods. However, it presents high cost and generally predictive equations are used in clinical practice, but little is known which is the best predictive equation of LM in women. The purpose of the present study was to verify which predictive equation of LM correctly estimates the LM in young and postmenopausal women.

METHODS

Eighty-one women aged 19-81 years were evaluated. Body weight, height, waist circumference, and skin folds (bicipital, tricipital, subscapular and suprailiac) were measured. The LM was evaluated by DXA and also estimated using the predictive equations of Hume I, Hume II, Salamat, Kulkarni I, and Kulkarni II. Bland-Altman analysis was performed to evaluate the over/underestimation of the LM by predictive equations.

RESULTS

The equations of Salamat, Kulkarni II, Hume I and Kulkarni I overestimated the LM by 0.0 (7.0; -6.9) kg; 2.3 (7.5; -3.0) kg; 5.1 (9.0; 0.4) kg; and 9.7 (16.3, 3.1) kg, respectively; whereas Hume II equation underestimated the LM by -16.9 (-11.5; -22.2) kg.

CONCLUSIONS

The equation that presented a better prediction of LM was Salamat. However, it should be used with caution in clinical practice since this equation showed elevated confidence intervals and limits of agreements, and can lead to significant errors for some individuals.

Higher Protein Intake Does Not Improve Lean Mass Gain When Compared with RDA Recommendation in Postmenopausal Women Following Resistance Exercise Protocol: A Randomized Clinical Trial

The aim of this study was to evaluate the effect of a higher protein intake on lean body mass (LBM) gain in postmenopausal women practicing resistance exercise and compare it to the Recommended Dietary Allowance (RDA) recommendation. Twenty-three postmenopausal women (63.2 ± 7.8 years) were randomized into two groups. The group with higher protein intake (n = 11) (HP) received a dietary plan with ~1.2 g·kg^-1·day^-1 of protein, while the normal protein (NP) group (n = 12) was instructed to ingest ~0.8 g·kg^-1·day^-1 of protein (RDA recommendation). Both groups performed the same resistance training protocol, 3 times a week, with progression of the number of sets (from 1 to 6 sets) and 8-12 repetitions. The intervention occurred over 10 weeks. Body composition evaluation was performed by dual-energy X-ray absorptiometry. The diet was evaluated by nine 24-h food recall summaries over the course of the study. During the intervention period, the HP group presented a higher protein (1.18 ± 0.3 vs. 0.87 ± 0.2 g·kg^-1·day^-1, p = 0.008) and leucine (6.0 ± 1.4 vs. 4.3 ± 0.9 g/day, p < 0.001) intake than the NP group, respectively. At the end of the intervention, there were increases in LBM both in HP (37.1 ± 6.2 to 38.4 ± 6.5 kg, p = 0.004) and in NP (37.6 ± 6.2 to 38.8 ± 6.4 kg, p < 0.001), with no differences between the groups (p = 0.572). In conclusion, increased protein intake did not promote higher LBM gain when compared to RDA recommendation in postmenopausal women performing resistance exercise during 10 weeks. This trial was registered at ClinicalTrials.gov as NCT03024125.

Adductor pollicis muscle thickness has a low association with lean mass in women

BACKGROUND & AIM

Lean mass (LM) is a functional component of body composition and is an important parameter of nutritional status assessment. The adductor pollicis muscle thickness (APMT) has been used as a predictor of LM, but it is not well known if this method presents a higher prediction of LM than simple anthropometric measurements, such as weight. Thus, we aimed to associate APMT (alone and plus weight) with LM in women.

METHODS

This cross-sectional study was conducted with 82 young and postmenopausal women. Body weight (Filizola®) and height (Welmy®) was quantified and APMT was measured by Lange® caliper. Body composition (LM and fat percentage) was estimated by dual-energy X-ray absorptiometry.

RESULTS

APMT was positively correlated with LM (r = 0.35; p = 0.001), however, weight was strongly correlated with LM (r = 0.81; p < 0.001). APMT showed a prediction of 12% of LM (β = 0.346, R² = 0.120, p < 0.001), and weight explained the variations of LM by 65% (β = 0.808, R² = 0.654, p < 0.001). When weight and APMT were evaluated together, there was an increase of only 0.06% in LM prediction (β = 0.820, R² = 0.655, p < 0.001), compared to weight alone.

CONCLUSION

When compared to weight, APMT showed a low association with LM. These results suggest that a simpler anthropometric measurement, such as weight, can be a better predictor of LM than APMT.