Fatigability and recovery of arm muscles with advanced age for dynamic and isometric contractions

This study determined whether age-related mechanisms can increase fatigue of arm muscles during maximal velocity dynamic contractions, as it occurs in the lower limb. We compared elbow flexor fatigue of young (n = 10, 20.8 ± 2.7 years) and old men (n = 16, 73.8 ± 6.1 years) during and in recovery from a dynamic and an isometric postural fatiguing task. Each task was maintained until failure while supporting a load equivalent to 20% of maximal voluntary isometric contraction (MVIC) torque. Transcranial magnetic stimulation (TMS) was used to assess supraspinal fatigue (superimposed twitch, SIT) and muscle relaxation. Time to failure was longer for the old men than for the young men for the isometric task (9.5 ± 3.1 vs. 17.2 ± 7.0 min, P = 0.01) but similar for the dynamic task (6.3 ± 2.4 min vs. 6.0 ± 2.0 min, P = 0.73). Initial peak rate of relaxation was slower for the old men than for the young men, and was associated with a longer time to failure for both tasks (P < 0.05). Low initial power during elbow flexion was associated with the greatest difference (reduction) in time to failure between the isometric task and the dynamic task (r = − 0.54, P = 0.015). SIT declined after both fatigue tasks similarly with age, although the recovery of SIT was associated with MVIC recovery for the old (both sessions) but not for the young men. Biceps brachii and brachioradialis EMG activity (% MVIC) of the old men were greater than that of the young men during the dynamic fatiguing task (P < 0.05), but were similar during the isometric task. Muscular mechanisms and greater relative muscle activity (EMG activity) explain the greater fatigue during the dynamic task for the old men compared with the young men in the elbow flexor muscles. Recovery of MVC torque however relies more on the recovery of supraspinal fatigue among the old men than among the young men.     

Effects of age and muscle action type on acute strength and power recovery following fatigue of the leg flexors

Short-term strength and power recovery patterns following fatigue have received little research attention, particularly as they pertain to age-specific responses, and the leg flexors (i.e., hamstrings) muscle group. Thus, research is warranted addressing these issues because both age-related alterations in the neuromuscular system and mode of muscle action (e.g., eccentric, concentric, isometric) may differentially influence recovery responses from fatigue. The aim of this study was to investigate the strength and power recovery responses for eccentric, concentric, and isometric muscle actions of the leg flexors in young and older men following an isometric, intermittent fatigue-inducing protocol. Nineteen young (age = 25 ± 3 years) and nineteen older (71 ± 4) men performed maximal voluntary contractions (MVCs) for eccentric, concentric, and isometric muscle actions followed by a fatigue protocol of intermittent (0.6 duty cycle) isometric contractions of the leg flexors at 60 % of isometric MVC. MVCs of each muscle action were performed at 0, 7, 15, and 30 min following fatigue. Peak torque (PT) and mean power values were calculated from the MVCs and the eccentric/concentric ratio (ECR) was derived. For PT and mean power, young men showed incomplete recovery at all time phases, whereas the older men had recovered by 7 min. Eccentric and isometric muscle actions showed incomplete recovery at all time phases, but concentric recovered by 7 min, independent of age. The ECR was depressed for up to 30 min following fatigue. More rapid and pronounced recovery in older men and concentric contractions may be related to physiological differences specific to aging and muscle action motor unit patterns. Individuals and clinicians may use these time course responses as a guide for recovery following activity-induced fatigue.     

The decline in skeletal muscle mass with aging is mainly attributed to a reduction in type II muscle fiber size

Background

The loss of skeletal muscle mass with aging has been attributed to a decline in muscle fiber number and muscle fiber size.

Objective

To define to what extent differences in leg muscle cross-sectional area (CSA) between young and elderly men are attributed to differences in muscle fiber size.

Methods

Quadriceps muscle CSA and type I and type II muscle fiber size were measured in healthy young (n = 25; 23 ± 1y) and older (n = 26; 71 ± 1y) men. Subsequently, the older subjects performed 6 months of resistance type exercise training, after which measurements were repeated. Differences in quadriceps muscle CSA were compared with differences in type I and type II muscle fiber size.

Results

Quadriceps CSA was substantially smaller in older versus young men (68 ± 2 vs 80 ± 2 cm², respectively; P < 0.001). Type II muscle fiber size was substantially smaller in the elderly vs the young (29%; P < 0.001), with a tendency of smaller type I muscle fibers (P = 0.052). Differences in type II muscle fiber size fully explained differences in quadriceps CSA between groups. Prolonged resistance type exercise training in the elderly increased type II muscle fiber size by 24 ± 8% (P < 0.01), explaining 100 ± 3% of the increase in quadriceps muscle CSA (from 68 ± 2 to 74 ± 2 cm²).

Conclusion

Reduced muscle mass with aging is mainly attributed to smaller type II muscle fiber size and, as such, is unlikely accompanied by substantial muscle fiber loss. In line, the increase in muscle mass following prolonged resistance type exercise training can be attributed entirely to specific type II muscle fiber hypertrophy.     

Differences in size, strength, and power of upper and lower body muscle groups in young and older men

We compared muscle thickness, torque, normalized torque (torque/muscle thickness), and power at 1.05 rad/s and 3.14 rad/s in flexor and extensor muscles of the elbow and knee, and in ankle plantar flexors in young (n=22, 18-31 years) and older (n=28, 59-76 years) men. Young men had greater muscle thickness for all muscle groups (p<.01), except elbow extensors, which were similar to older men. Young men had greater torque and power at both velocities for all muscle groups (p<.01), and greater normalized torque at both velocities for the elbow extensors and knee flexors and at the fast velocity for knee extensors. Relative to young mean values, muscle thickness, and torque, normalized torque, and power in the older group were most affected for lower-body measurements, especially at the fast velocity. Torque, normalized torque, and power (especially at fast velocities), and muscle thickness in the lower body are affected more by aging than are upper body measures in men.     

Neuromechanical properties of the triceps surae in young and older adults

The aim of this study was to compare voluntary and involuntary force generating capacity of the triceps surae muscles in healthy young and older adult participants during isometric and isokinetic contractions. Ultrasound was used to measure medial gastrocnemius (MG) fascicle length during maximal voluntary isometric contractions and supra-maximal isometric twitch contractions at five ankle angles throughout the available range of motion, as well as isokinetic concentric and eccentric contractions at four ankle velocities. Maximum voluntary activation of the plantar flexors was assessed using the twitch interpolation technique. Peak plantar flexor torque was significantly lower in older adults compared to young participants by 42%, 28% and 43% during maximal voluntary isometric contractions, supra-maximal isometric twitch and concentric contractions respectively. No age-related differences in eccentric torque production were detected. When age-related differences in triceps surae muscle volume determined from MRI were taken into account, the age-related peak plantar flexor torque deficits for maximum voluntary isometric, supra-maximal twitch, and concentric contractions were 24%, 19% and 24% respectively. These age-related differences in torque were not explained by torque–length–velocity behaviour of the MG muscle fascicles, passive plantar flexor torque–angle properties, decreased neural drive of the plantar flexor muscles or antagonistic co-activation of the tibialis anterior muscle. The residual deficit in isometric and concentric plantar flexor torques in healthy older adults may involve reduced muscle quality. A significant reduction in supra-maximal twitch torque at longer MG fascicle lengths as well as a lower MG fascicle velocity during eccentric contractions in older adults was detected, which could possibly be a function of the reported increased Achilles tendon compliance in older adults.     

Body composition,physical performance and muscle quality of active elderly women

Fat gain is one of the major factors aggravating physical disability in the elderly population, which presents an increase in fat mass and a decrease in lean mass compared to the young population. For this reason it is important to assess body composition and the effects of these alterations in obese elderly women. The purpose of this study was to assess body composition, physical performance and muscle quality in active elderly women. Cross-sectional study included 75 elderly women (29 eutrophic and 46 obese) 65–80 years old. Body composition was evaluated by dual energy X-ray absorptiometry (DXA) and the physical performance was determined by 6-minute walk test (6MWT), handgrip strength (HS) and knee extension strength (KES). Muscle quality was calculated as the ratio between muscle strength and lean mass. Fat free mass, lean mass, fat mass and percent body fat were significantly higher in the obese group (p < 0.05). Furthermore, the obese group showed a poorer performance than the eutrophic group in the 6MWT (432.31 ± 66.13 m and 472.07 ± 74.03 m, respectively, p = 0.01). HS and KES did not differ between groups, however, regarding muscle quality, the obese group exhibited a impaired in comparison to the eutrophic group in the upper (11.45 ± 2.57 kg and 13.31 ± 2.03 kg, respectively, p < 0.01) and lower limb (2.91 ± 1.16 kg and 3.44 ± 0.97 kg, respectively, p = 0.05). The increase in muscle mass detected in the obese elderly was not sufficient to maintain adequate muscle quality and physical function, showing a negative influence of the excess of body fat.     

Measurement of myostatin concentrations in human serum: Circulating concentrations in young and older men and effects of testosterone administration

Methodological problems, including binding of myostatin to plasma proteins and cross-reactivity of assay reagents with other proteins, have confounded myostatin measurements. Here we describe development of an accurate assay for measuring myostatin concentrations in humans. Monoclonal antibodies that bind to distinct regions of myostatin served as capture and detector antibodies in a sandwich ELISA that used acid treatment to dissociate myostatin from binding proteins. Serum from myostatin-deficient Belgian Blue cattle was used as matrix and recombinant human myostatin as standard. The quantitative range was 0.15–37.50 ng/mL. Intra- and inter-assay CVs in low, mid, and high range were 4.1%, 4.7%, and 7.2%, and 3.9%, 1.6%, and 5.2%, respectively. Myostatin protein was undetectable in sera of Belgian Blue cattle and myostatin knockout mice. Recovery in spiked sera approximated 100%. ActRIIB-Fc or anti-myostatin antibody MYO-029 had no effect on myostatin measurements when assayed at pH 2.5. Myostatin levels were higher in young than older men (mean ± S.E.M. 8.0 ± 0.3 ng/mL vs. 7.0 ± 0.4 ng/mL, P = 0.03). In men treated with graded doses of testosterone, myostatin levels were significantly higher on day 56 than baseline in both young and older men; changes in myostatin levels were significantly correlated with changes in total and free testosterone in young men. Myostatin levels were not significantly associated with lean body mass in either young or older men.     

Longitudinal muscle strength changes in older adults: influence of muscle mass, physical activity, and health

The longitudinal changes in isokinetic strength of knee and elbow extensors and flexors, muscle mass, physical activity, and health were examined in 120 subjects initially 46 to 78 years old. Sixty-eight women and 52 men were reexamined after 9.7 +/- 1.1 years. The rates of decline in isokinetic strength averaged 14% per decade for knee extensors and 16% per decade for knee flexors in men and women. Women demonstrated slower rates of decline in elbow extensors and flexors (2% per decade) than men (12% per decade). Older subjects demonstrated a greater rate of decline in strength. In men, longitudinal rates of decline of leg muscle strength were approximately 60% greater than estimates from a cross-sectional analysis in the same population. The change in leg strength was directly related to the change in muscle mass in both men and women, and it was inversely related to the change in medication use in men. Physical activity declined yet was not directly associated with strength changes. Although muscle mass changes influenced the magnitude of the strength changes over time, strength declines in spite of muscle mass maintenance or even gain emphasize the need to explore the contribution of other cellular, neural, or metabolic mediators of strength changes.     

Association of cognitive function with serum uric acid level among Chinese nonagenarians and centenarians

This cross-sectional study aimed to assess the association of risk of cognitive impairment with level of serum uric acid (SUA) among very old people, specifically in a cohort of 694 unrelated Chinese aged 90–108 years. Cognitive function was measured using the 30-item Mini-Mental State Examination (MMSE) and SUA level was determined by the uricase–peroxidase method. Cognitive impairment was defined as a score below 18 on the Folstein MMSE. Men had significantly higher cognitive function scores than did women: 17.6 ± 5.6 vs. 14.0 ± 5.2 (P < 0.05). In the total sample, the prevalence of cognitive impairment was 71.6%, with the rates being 50.9% and 81.6% for males and females, respectively (P < 0.000). Men had significantly higher SUA levels than women: 354.1 ± 85.7 vs. 303.8 ± 81.7 mmol/L (P = 0.000). Binary logistic regression analysis indicated an inverse correlation between the risk of cognitive impairment and SUA (OR = 0.996) in men. In conclusion, in male nonagenarians and centenarians, the higher level of SUA is related to the lower risk of cognitive impairment.     

Development and preliminary validation of a new scale to assess functional ability of older population in India

Identifying the decline in functional ability and preventing disability is the critical element of the quality of life of an old age. However, the lack of contextual scale to assess the decline in functional capacity is a major issue. Objective of this study is to design the functional ability assessment scale for elderly people in India and test its psychometric properties. Random sample of 659 individuals above 60 years of age from western part of India was recruited. This paper outlines the construction, reliability and validity of a newly developed 14 item scale named as Pune-Functional Ability Assessment Tool (Pune-FAAT). The factors were extracted using the principal component analysis. Two-factor-structure of scale was accepted after applying the K1 rule, scree plot and parallel analysis method. The two factor structure yielded variance of 64.4%. The psychometric properties of the scale were examined using confirmatory factor analysis. The scale has an excellent reliability (Cronbach's α 0.928) and very good test–retest reliability (r = 0.884). Each subscale demonstrated good internal consistency (Subscale I – Cronbach's α 0.938 and Subscale II – Cronbach's α 0.762). Excellent convergent validity with Standford's health assessment questionnaire (r = 0.959). Discriminant validity was very good as FAAT index showed significant difference in young adults (mean ± SD 1.11 ± 0.24) and older adults (mean ± SD 1.69 ± 0.70). This new measure is a potentially valuable research tool for investigating older adult's functional ability to perform basic and complex daily activities.     

Frailty and migration in middle-aged and older Europeans

We evaluated life course influences on health by investigating potential differences in levels of frailty between middle-aged and older European immigrants born in low- and middle-income countries (LMICs), immigrants born in high income countries (HICs), and their native-born European peers. Using data from the Survey of Health, Ageing, and Retirement in Europe (SHARE), we constructed a frailty index from 70 age-related health measures for 33,745 participants aged 50+ (mean = 64.9 ± 10.2 years; 54% women) in 14 European countries. Participants were grouped as native-born or as immigrants born in LMICs or in HICs, and further by current residence in Northern/Western or Southern/Eastern Europe. Seven percent of participants (n = 2369) were immigrants (mean = 64.4 ± 10.2 years; 56% women; LMIC-born = 3.4%, HIC-born = 3.6%). In Northern/Western Europe, after adjustment for age, gender, and education, LMIC-born immigrants demonstrated higher frailty index scores (mean = 0.18, 95% confidence interval = 0.17–0.19) than both HIC-born immigrants (0.16, 0.16–0.17) and native-born participants (0.15, 0.14–0.15 both p < 0.001). In Southern/Eastern Europe, frailty index scores did not differ between groups (p = 0.2). Time since migration explained significant variance in frailty index scores only in HIC-born immigrants to Southern/Eastern Europe (4.3%, p = 0.03). Despite differences in frailty, survival did not differ between groups (p = 0.2). LMIC-born immigrants demonstrated higher levels of frailty in Northern/Western Europe, but not Southern/Eastern Europe. Country of birth and current country of residence were each associated with frailty. Life course influences are demonstrable, but complex.     

Four days of muscle disuse impairs single fiber contractile function in young and old healthy men

The purpose of the study was to investigate the effects of 4 days of disuse (knee brace) on contractile function of isolated vastus lateralis fibers (n = 486) from 11 young (24.3 ± 0.9 yrs) and 11 old (67.2 ± 1.0 yrs) healthy men having comparable levels of physical activity. Prior to disuse single fiber specific force (maximal Ca^2 +-activated force per cross-sectional area) was lower in MHC I vs. IIa fibers (p < 0.05) both in young (44%) and old (32%), and specific force of MHC IIa fibers was lower in old vs. young (19%, p < 0.05). Further, Ca^2 + sensitivity was higher in MHC I vs. IIa fibers (p < 0.05) in both age groups. Following disuse single fiber specific force decreased (p < 0.05) in MHC I fibers in young (− 19%) and old (− 17%), and in MHC IIa fibers in young (− 21%) but not in old (− 11%; ns). The extent of these decreases did not differ between young and old. Ca^2 + sensitivity decreased (p < 0.05) in MHC I fibers in old (− 0.11 pCa units) but not in young (− 0.08 pCa units; ns). The extent of these decreases was greater in old vs. young (p < 0.05). In conclusion, 4 days of lower limb disuse led to marked impairments in single muscle fiber specific force independently of age, while changes in Ca^2 + sensitivity were dependent on age and MHC isoform composition. The present findings stress the importance of determining and implementing effective preventive and rehabilitative approaches for old individuals exposed to as little as 4 days of disuse.     

High homocysteine and low folate concentrations in acute aortic dissection

Background

Biomarkers for monitoring progression and prognosis of thoracic aneurysm are of great interest. Homocysteine (Hcy) induces elastolysis in arterial media and may directly affect fibrillin-1 or collagen whereas lipoprotein (Lp) (a) inhibits elastolysis by reducing activation of matrix metallopeptidase-9.

Methods

We studied 31 consecutive patients with acute aortic dissection (AAD) admitted for emergency surgery (group I, 60 ± 13 years old, 25 men), 30 consecutive patients with chronic aneurysms of the ascending aorta (group II, 67 ± 12 years old, 24 men) and 20 healthy controls (group III, 58 ± 15 years old, 14 men). We evaluated Hcy, folate, B12, Lp(a) and methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism at baseline.

Results

Hcy, folate and B12 differed significantly among the 3 studied groups (P = 0.016, P = 0.004 and P = 0.001, respectively). The levels of Hcy and B12 were significantly higher in group I compared to both groups II and III (P = 0.05 and P = 0.002, P < 0.001 and P = 0.017, respectively) and without significant differences between groups II and III (P = 0.083 and P = 0.124). Folate was significantly lower in group I compared to both groups II and III (P = 0.001 and P = 0.006, respectively) and without marked difference between groups II and III (P = 0.409). No significant difference was found in serum levels of Lp (a) (P = 0.074) or among the frequency of MTHFR C677T genotypes.

Conclusions

Patients with AAD present with higher Hcy and lower folate compared to both chronic aneurysms and controls.     

The obesity gene and colorectal cancer risk: a population study in Northern Italy

Background

Representing the second cause of cancer-related death after lung cancer in men and breast cancer in women, colorectal cancer (CRC) is a major health problem in Italy. Obesity is reckoned to favor CRC; however, the underlying mechanisms are unclear. Recently, a single nucleotide polymorphism (SNP) in the fat mass and obesity associated (FTO) gene was found to be significantly associated with obesity.

Aims

To establish whether the FTO SNP rs9939609 may represent a risk factor for CRC and adenoma in the Italian population.

Patients and methods

1,037 subjects were enrolled in the study and divided in 3 groups: CRC (341 pts., M/F = 197/144, mean age = 65.17 ± 11.16 years), colorectal adenoma (385 pts., M/F = 247/138, mean age = 62.49 ± 13.01 years), healthy controls (311 pts., M/F = 150/161, mean age = 57.31 ± 13.84 years). DNA was extracted from whole blood, and stored frozen for rs9939609 genotyping by real-time PCR.

Results

The frequency of the obesity-associated mutated A allele (AA+AT) on the FTO gene was 69.77% among controls, and 71.85% and 65.71% respectively among CRC and polyp patients. Compared to control subjects the AA+AT genotype had no significant effect on the risk for either CRC (OR = 1.106; CI 95% = 0.788-1.550; p = 0.561) or colorectal adenomas (OR = 0.830; CI 95% = 0.602-1.144; p = 0.255). We did not observe any association between the AA genotype and CRC/polyp localization and age at diagnosis. As measured in a patient subset, carriership of the risk alleles did not reflect in a significantly altered BMI.

Conclusion

The obesity-linked FTO variants do not play a significant role in modulating the colorectal cancer risk in the Italian population.     

The age-related slowing of voluntary shortening velocity exacerbates power loss during repeated fast knee extensions

Older adults are less fatigable than young during isometric tasks, but this apparent ability to resist fatigue is often abolished when dynamic actions are performed. These findings could indicate that the velocity component of dynamic contractions or the task performed is an important factor in explaining fatigability of older adults. However, it has not been evaluated systematically. The purpose was to investigate the differences in age-related fatigue of the knee extensors in 8 older (73.6 ± 3.5 years) and 8 younger (25.1 ± 2.6 years) men. Neuromuscular measures were collected at baseline, during and immediately following task termination of three different maximal effort knee extension tasks. On three separate days, participants performed either 30 slow (1.05 rad·s^− 1, 60°·s^− 1) or 30 moderate (3.14 rad·s^− 1, 180°·s^− 1) isovelocity contractions, or 30 fast unconstrained velocity contractions with a fixed resistance (i.e., 20% maximal voluntary isometric contraction). At baseline, the older men were 25% and 35% less powerful than the younger men for the slow and moderate isovelocity tasks, respectively, but 42% less for the fast unconstrained velocity protocol. At task termination for the slow (old: 53%, young: 53%) and moderate (old: 45%, young: 38%) isovelocity fatigue tasks, power was reduced similarly in both age groups. However, for the fast unconstrained velocity task, power was reduced by a greater extent in older (35%) than the younger men (23%) at task termination. These results highlight that age-related impairments in voluntary shortening velocity exacerbate reductions in power production during repetitive dynamic tasks. Furthermore, the importance of this factor is masked when velocity is constrained (isovelocity) and fatigue is dependent primarily upon slow torque generation.     

Reduced functionality in everyday activities of patients with self-reported heart failure hospitalization — Population-based study results

Aim

To assess daily functioning and geriatric conditions of older subjects suffering from heart failure (HF) as compared to the general population.

Methods and results

The data were collected as part of the nationwide PolSenior project (2007–2011). Of 4979 individuals (age range 65–104 years), data on self-reported HF hospitalization were available for 4795 subjects (96%). Geriatric assessment (GA) included functional status (ADL, Activities of Daily Living and IADL, Instrumental ADL scales), cognitive function, mood disorders, sensory organ impairment, falls and comorbidity. Mean age ± SD of the study population was 73.8 ± 6.5 years; 62% were female. The proportion of subjects with HF hospitalizations increased from 8% in subjects aged 65–69 years up to 13% in the age group of 85–89 years, and decreased in nonagenarians (11%). Subjects with the HF hospitalization were older, used more drugs, and were characterized by a higher prevalence of comorbid conditions, mood disorders, hearing impairment and functional limitations. In logistic regression, HF hospitalization increased the age–sex adjusted risk of disability by 40%, both in ADL and IADL. After adjustment to other clinical and geriatric conditions, HF hospitalization remained an independent predictor of disability in both ADL (OR = 1.36, 95%CI: 1.00–1.84) and IADL (OR = 1.40, 95%CI: 1.01–1.93).

Conclusions

Older people who reported HF admissions had a higher number of comorbidities and geriatric conditions: mood disorders, hearing impairment and functional limitations. Besides, in our study, HF hospitalization independently and significantly increased the risk of limitations in IADL and ADL. Therefore, further studies are needed to evaluate the benefits of GA in patients with HF.     

Differences in muscle coactivation during postural control between healthy older and young adults

The purpose of this study was to clarify the difference in muscle coactivation during postural control between older and young adults and to identify the characteristics of postural control strategies in older adults by investigating the relationship between muscle coactivation and postural control ability. Forty-six healthy older adults (82.0 ± 7.5 years) and 34 healthy young adults (22.1 ± 2.3 years) participated. The postural tasks selected consisted of static standing, functional reach, functional stability boundary and gait. Coactivation of the ankle joint was recorded during each task via electromyography (EMG). The older adults showed significantly higher coactivation than the young adults during the tasks of standing, functional reach, functional stability boundary (forward), and gait (p < 0.01). Postural sway area (ρ = 0.42, p < 0.05) and functional reach distance (ρ = −0.52, p < 0.05) significantly correlated with coactivation during the corresponding task in older adults, i.e., muscle coactivation was significantly higher in the elderly with low postural control ability than in the elderly with high balance ability. Increased muscle coactivation could be a necessary change to compensate for a deterioration in postural control accompanying healthy aging. Further research is needed to clarify in greater detail positive and negative effects of muscle coactivation on postural control.     

Population trends and inequalities in incidence and short-term outcome of acute myocardial infarction between 1998 and 2007

Objective

We studied time trends in acute myocardial infarction (AMI) incidence, including out-of-hospital mortality proportions and hospitalized case-fatality rates. In addition, we compared AMI trends by age, gender and socioeconomic status.

Methods

We linked the national Dutch hospital discharge register with the cause of death register to identify first AMI in patients ≥ 35 years between 1998 and 2007. Events were categorized in three groups: 178,322 hospitalized non-fatal, 43,210 hospitalized fatal within 28 days, and 75,520 out-of-hospital fatal AMI events. Time trends were analyzed using Joinpoint and Poisson regression.

Results

Since 1998, age-standardized AMI incidence rates decreased from 620 to 380 per 100,000 in 2007 in men and from 323 to 210 per 100,000 in 2007 in women. Out-of-hospital mortality decreased from 24.3% of AMI in 1998 to 20.6% in 2007 in men and from 33.0% to 28.9% in women. Hospitalized case-fatality declined from 2003 onwards. The annual percentage change in incidence was larger in men than women (− 4.9% vs. − 4.2%, P < 0.001). Furthermore, the decline in AMI incidence was smaller in young (35–54 years: − 3.8%) and very old (≥ 85 years: − 2.6%) men and women compared to middle-aged individuals (55–84 years: − 5.3%, P < 0.001). Smaller declines in AMI rates were observed in deprived socioeconomic quintiles Q5 and Q4 relative to the most affluent quintile Q1 (P = 0.002 and P = 0.015).

Conclusions

Substantial improvements were observed in incidence, out-of-hospital mortality and short-term case-fatality after AMI in the Netherlands. Young and female groups tend to fall behind, and socioeconomic inequalities in AMI incidence persisted and have not narrowed.     

Association between skeletal muscle mass and radial augmentation index in an elderly Korean population

Increasing evidence supports the importance of maintaining skeletal muscle mass for cardiovascular health. However, there is limited data on the relationship between skeletal muscle mass and arterial stiffness targeting an elderly population. Thus, we investigated the association between skeletal muscle mass and arterial stiffness in an elderly Korean population. This study used data from the Korean Social Life, Health and Aging Project which started in 2011. In this cross-sectional study, 180 men (mean age 71.7) and 247 women (mean age 70.9) were included. Arm and leg muscle masses were measured by bioelectrical impedance analysis. Radial augmentation index, a noninvasive measure of arterial stiffness, was assessed by radial pulse wave analysis. The relationship between skeletal muscle mass and augmentation index was investigated by multiple linear regression analysis. In men, limb muscle mass was significantly and inversely associated with augmentation index (β = −1.07% per 1 kg muscle mass, p < 0.001) when adjusted for age. This inverse association remained after additional adjustment for body mass index, systolic blood pressure, total cholesterol, high-density lipoprotein-cholesterol, fasting glucose, insulin, smoking and alcohol intake (β = −0.69%, p = 0.019). In women, the inverse association between limb muscle mass and augmentation index was less prominent (β = −0.59%, p = 0.030), and the association disappeared when fully adjusted (β = −0.32%, p = 0.304). However, limb muscle mass was not associated with resting blood pressure either in men or women. Our results suggest that decreased skeletal muscle mass may affect arterial wall elasticity.