Hemoglobin A1c and 10-year information processing speed in Japanese community dwellers

BACKGROUND@#Hyperglycemia is believed to be a risk factor for cognitive decline, but the longitudinal relationship between hyperglycemia and cognitive decline in the Japanese population is unclear. The present study aimed to clarify the association between blood glucose levels and information processing ability in middle-aged and older adults.@*METHODS@#The subjects were 866 men and 815 women aged 40-79 years not taking medication for diabetes who participated in the first study wave (1997-2000) and then participated at least once in the subsequent six study waves (2000-2012) of the National Institute for Longevity Sciences-Longitudinal Study of Aging, Japan. Hemoglobin A1c (HbA1c) levels were categorized into four groups (< 5.6, 5.6 to < 6.0, 6.0 to < 6.5, ≥ 6.5%), and a mixed-effects model was used to evaluate the effects of the HbA1c level (four groups) on repeated measures of information processing speed. The models also included baseline age, body mass index, ethanol intake, smoking status, educational level, family income, and history of stroke, hypertension, heart disease, and dyslipidemia as covariates.@*RESULTS@#Mean (standard deviation) HbA1c and follow-up time in participants were 5.2 (0.5) % and 10.0 (3.6) years, respectively. A linear mixed model showed that the main effect of the four HbA1c groups on information processing ability was not significant in either men or women, but the interaction of HbA1c and time with information processing speed in the higher HbA1c level groups (≥ 6.5% group in men, 6.0 to < 6.5% and ≥ 6.5% groups in women) was significant compared to the lower HbA1c level (< 5.6%) group (P < 0.05). When the slope of information processing speed by HbA1c level at baseline was examined, the slope of information processing speed in the higher HbA1c level (≥ 6.5%) group was higher than in the lower HbA1c level (< 5.6%) group, both in men (- 0.31/year) and in women (- 0.30/year), as well as in women with an HbA1c level of 6.0 to < 6.5% (- 0.40/year).@*CONCLUSIONS@#Higher baseline HbA1c was associated with greater subsequent decline in information processing ability in Japanese community dwellers, even with the pre-clinical HbA1c level (6.0 to < 6.5%) in women. The results suggest that good glycemic control or prevention of hyperglycemia may contribute to maintaining information processing ability.

Long-term longitudinal epidemiological study of frailty and sarcopenia / 体力科学

<p>The state in which physical and mental functions are deteriorated with aging is called frailty, and decrease in muscle mass and muscle strength with aging accompanying deterioration of physical function is called sarcopenia. Frailty and sarcopenia are found in older adults, which is a major obstacle to achieve healthy longevity. Estimation of prevalence and number of patients, as well as elucidation of risk factors in frailty and sarcopenia are important for the prevention of frailty and sarcopenia. The prevalence of frailty determined by criteria based on the method of Fried et al. was 5.2% for men and 20.9% for women in a cohort of randomly selected community-living population, and the estimated number of people with frailty was about 0.77 million men and 2,22 million women among the population aged 65 years and over in Japan. The prevalence of sarcopenia by the Asian Working Group for Sarcopenia (AWGS) criteria was 9.6% for men and 7.7% for women. The number of people aged 65 years and over with sarcopenia in Japan was estimated to be 1.64 million for men and 1.39 million for women. The onset of frailty was related to physique, physical function, cognitive function, depression, and various chronic diseases. Depression and lack of exercise were significant risk factors of sarcopenia. Physical activity, nutrition and control of chronic diseases are required for the prevention of frailty and sarcopenia, and the prevention will be an important issue for health and longevity in Japan.</p>

AGE-RELATED CHANGES OF POSTURAL STABILITY AND PHYSICAL FUNCTION IN MIDDLE-AGED AND ELDERLY JAPANESE / 体力科学

The aim of the present study was to clarify the relationships between age-related changes of postural stability and physical function in middle-aged and elderly Japanese. The subjects were 640 males and 620 females who had participated in both the baseline and the 4-year follow-up surveys of the National Institute for Longevity Sciences-Longitudinal Study of Aging. Postural stability was measured using a force platform. Flexibility, muscle function, reaction time, balance and comfortable and maximal gait performance were also measured as physical function. Postural sway was increased in 4 years. Multiple logistic regression analysis controlled for age, sex, height, weight and history of diseases revealed significant relationships between decline of postural stability and sit-ups, flexibility, frequency and velocity at comfortable gait and leg extension power at baseline. These results suggest that not only greater abdominal muscle strength and leg power but also quick walking benefit the preservation of postural stability.