Correlation between muscle strength and muscle mass, and their association with walking speed, in community-dwelling elderly Japanese individuals

OBJECTIVES

We aimed to assess the correlation between muscle strength and muscle mass based on sex and age, and their association with walking speed, which is a health predictor for independent living, in elderly Japanese individuals.

METHODS

The participants included 318 (111 men, 207 women) community-dwelling elderly Japanese individuals aged ≥65 years. Knee extension strength was assessed as an indicator of muscle strength, and bioelectrical impedance analysis was used to measure muscle mass. The maximum walking speed of participants was recorded. All measurements were categorized based on sex and age groups as follows: young-old (age, 65-74 years) and old-old (age, ≥75 years).

RESULTS

Appendicular muscle mass and knee extension strength decreased with age in both men and women. In men, knee extension strength showed significant positive correlations with leg and appendicular muscle mass in both young-old and old-old age groups. However, in women, only the old-old age group showed significant positive correlations between knee extension strength and leg and appendicular muscle mass. Muscle strength was significantly positively correlated with maximum walking speed in all groups, whereas muscle mass was not significantly correlated with maximum walking speed in men and women.

CONCLUSIONS

Muscle strength was significantly correlated with muscle mass in both age groups in men. However, in women, the correlation between muscle strength and muscle mass differed according to age. This finding suggests that the relationship between muscle strength and muscle mass differs according to sex and age. Muscle strength showed significant correlation with walking speed in both men and women in both age groups. These findings suggest that it is necessary to recognize that muscle strength is different from muscle mass, and that an individualized approach to prevent decline of muscle strength and muscle mass is necessary for health promotion in elderly.

The current situation of voluntary vaccination and the factors influencing its coverage among children in Takatsuki, Japan: focus on Hib and pneumococcal vaccines

This study aimed to understand the current scenario of voluntary vaccination and the factors influencing its coverage among 18-month-old children of Takatsuki City, Japan. Based on 1167 parents responses, we found that voluntary vaccination coverage rates were low when compared with routine vaccination rates. The children who were not the first born of the family and who had young and poorly educated parents were less likely to receive voluntary vaccination. Japanese government-supported vaccines, such as Haemophilus influenzae type b and pneumococcal vaccine, had a higher coverage than the vaccines for which parents had to bear the entire vaccination cost. Furthermore, it was found that mass communication media and family pediatricians were effective means to disseminate voluntary vaccination-related information. We envisage that an active participation of medical professionals, easy access to vaccinations, and mass awareness programs will increase voluntary vaccination coverage in Takatsuki.

Association of sarcopenia with functional decline in community-dwelling elderly subjects in Japan

AIM

The present study aimed to determine the association of sarcopenia, defined by muscle mass, muscle strength and physical performance, with functional disability from a 2-year cohort study of community-dwelling elderly Japanese people.

METHOD

Participants were 743 community-dwelling elderly Japanese people aged 65 years or older. We used bioelectrical impedance analysis (BIA) to measure muscle mass, grip strength to measure muscle strength, and usual walking speed to measure physical performance in a baseline study. Functional disability was defined using an activities of daily living (ADL) scale and instrumental activities of daily living (IADL) scale at baseline and during follow-up examinations 2 years later. Logistic regression analysis, adjusted for age and body mass index, was used to examine the association between sarcopenia and the occurrence of functional disability.

RESULTS

In the present study, 7.8% of men and 10.2% of women were classified as having sarcopenia. Among sarcopenia patients in the baseline study, 36.8% of men and 18.8% of women became dependent in ADL at 2-year follow up. From the logistic regression analysis adjusted by age and body mass index, sarcopenia was significantly associated with the occurrences of physical disability compared with normal subjects in both men and women.

CONCLUSIONS

Sarcopenia, defined by muscle mass, muscle strength and physical performance, was associated with functional decline over a 2-year period in elderly Japanese. Interventions to prevent sarcopenia are very important to prevent functional decline among elderly individuals.

[Factors related to sarcopenia in community-dwelling elderly subjects in Japan]

OBJECTIVES

This study aimed at determining the factors associated with sarcopenia, defined as low muscle mass and strength and low physical performance, in community-dwelling elderly subjects in Japan.

METHODS

The subjects included 1,074 elderly, community-dwelling Japanese people aged 65 years or older. We measured appendicular muscle mass (AMM) by bioelectrical impedance analysis, grip strength, and usual walking speed. A low muscle mass was defined by the AMM index (AMI, weight [kg]/height [m(2)] as >2 standard deviations below the mean AMI for normal young subjects. The lowest quartile for grip strength and usual walking speed were classified as low muscle strength and low physical performance, respectively. "Sarcopenia" was characterized by a low muscle mass, combined with either a low muscle strength or low physical performance. Subjects without low muscle mass or strength and low physical performance were classified as "normal." Subjects were classified as being "intermediate" if they were neither "sarcopenic" nor "normal." Items in the questionnaire included residential status, past medical history, admission during the past year, smoking and drinking habits, leisure-time physical activity, health status, depression, masticatory ability, and dietary variety score.

RESULTS

Sarcopenia was identified in 13.7% of men and 15.5% of women. Among men, a large proportion of subjects with sarcopenia had poor masticatory ability and a low dietary variety score compared with normal or intermediate subjects. Among women, a large proportion of the subjects with sarcopenia lived alone, had poor exercise habits, considered themselves to be unhealthy, and had poor masticatory ability compared with normal or intermediate subjects. A multiple logistic regression analysis showed that age and dietary variety in men and age and masticatory ability in women were associated with sarcopenia.

CONCLUSION

The present study carried out in Japan showed that sarcopenia, assessed by muscle mass, muscle strength, and physical performance, was associated with age, dietary variety score (in men), and masticatory ability (in women).