The TMIG has been conducting the longitudinal interdisciplinary study on aging (TMIG-LISA) to examine the changes in physical function of the elderly, to identify factors retarding or accelerating the rate of aging and to establish ways for successful aging in elderly residents for 10 years. The subjects consist of 735 persons aged over 65 years living in a mountain-ringed rural community, Akita prefecture, in the northern part of Japan. The first survey was conducted in 1992. Since then, the same survey has been performed on the same persons every 2 years. In 2002, the fifth follow-up survey was conducted on 1,327 subjects including 303 subjects who participated at baseline survey in 1992. The survey involved medical examination of more than 100 parameters as well as interview.
The present study analyzed 4 measurements (grip strength, one-leg standing time with eyes open, usual walking speed, and maximum walking velocity) concerning physical function that are important factors determining functional capacity. In a comparison of the 1992 and 2002 cohorts, close similarities in the distribution pattern of measurements in those over 65 years of the 1992 cohort were found in those over 69 years for grip strength, in those over 76 years for usual walking speed, and in those over 69 years for maximum walking speed in men and in those over 75, 76, and 73 years in women of 2002 cohort, respectively. From the results of the analysis, it was concluded that, in the 2002 cohort, men and women were functionally younger by 4-11 years and 8-11 years, respectively, compared with those in the 1992 cohort. Conventionally, "elderly" has been defined as a chronological age of 65 years old or older, while those from 65 through 74 years old are referred to as "young-old" and those over 75 years old as "old-old." However, the evidence on which this definition is based is unknown.
Our findings on longitudinal and cross-sectional changes of physical function from TMIG-LISA suggest that a definition of elderly to simply include all persons over 65 years might be no longer be appropriate in this era with a life expectancy of 80 years. What has increased is healthy life expectancy rather than simply the time spent alive, so there are more bright and energetic elderly people compared with a couple of decades ago in Japan. In addition, our recent findings on a few biological markers related to mortality and sarcopenia in the elderly from TMIG-LISA will also be introduced in the symposium.
Recent Selected Publications:
1 Suzuki T, Shibata H: An introduction of The TMIG-LISA (1999-2001). Geriatr. Gerontol. International. 2003, 3: S1-4.
2 Suzuki T, Yoshida H., Kim H. Yukawa H., Furuna T., Sugiura M., Ishizaki T: Walking speed as a good indicator for maintenance of I-ADL among the rural community elderly in Japan: A 5-year follow-up study from TMIG-LISA. Geriatr. Gerontol. International. 2003, 3: S6-14.
3 Suzuki T, Kim H, Yoshida H, et al: Randomized controlled trial of exercise intervention for the prevention of falls in community-dwelling elderly Japanese women. J Bone Min. Metab. 2004, 22: 602-611.
4 Ishizaki T, Yoshida H, Suzuki T, Watanabe S and Kim H: Effects of cognitive function on functional decline among community-dwelling non-disabled older Japanese. Arch Gerontol Geriatr. 42: 47-58, 2006.
5 Kwon J, Suzuki T, Kumagai S, Yukawa H: Risk factors for dietary variety decline among Japanese elderly in a rural community: an 8-year follow-up study from TMIG-LISA. European Journal Clinical Nutrition. 30, 305-311, 2006.
6 Kwon J, Suzuki T, Yoshida H, Kim H, Yoshida Y, Iwasa H, Sugiura M, Furuna T: Association between change in bone mineral density and decline in usual walking speed among Japanese community elderly women during 2-year follow-up. Journal of American Geriatrics Society, 55(2); 240-244, 2007.
7 Kwon J, Suzuki T, Yoshida H, Kim H, Yoshida Y, Iwasa H et al: Concomitant lower serum albumin and vitamin D levels are associated with decreased objective physical performance among Japanese community-dwelling elderly. Gerontology 53: 322-328, 2007.
8 H, Kim H, Yoshida Y, Kwon J, Sugiura M, Furuna T, Suzuki T: A mortality comparison of participants and non-participants in a comprehensive health examination among elderly people living in an urban Japanese community. Aging: Clinical and Experimental Research 19(3), 240-245, 2007.
9 Shimada H, Lord S, Yoshida H, Kim H, Suzuki T: Predictors of cessation of regular leisure-time physical activity in community-dwelling elderly people. Gerontology 53: 293-297, 2007.
10 Kusumoto A, Suzuki T, Yoshida H, Kwon J: Intervention study to improve quality of life and health problems of community-living elderly women in Japan by shoe filling and custom-made insoles. Gerontology 53: 110-118, 2007.
11 Kim H, Suzuki T, Yoshida Y, Yoshida H: Effectiveness of multidimensional exercises for the treatment of stress urinary incontinence in community-dwelling Japanese elderly women: A randomized controlled and cross-over trial. J Am Geriatr Soc. 55: 1932-1939, 2007.
12 Shimada H, Kimura Y, Suzuki T, Hirata T, Sugiura M, Endo Y, Yasuhara K, Shimada K, Kikuchi K, Hashimoto M, Ishikawa M, Oda K, Ishii K, Ishiwata K: The use of positron emission tomography and [18F] fluorodeoxyglucose for functional imaging of muscular activity during exercise with a stride assistance system. IEEE Transre. 15: 442-448, 2007.
13 Suzuki T, Kwon J, Kim H, Shimada H, Yoshida Y, Iwasa H, Yoshida H: Low serum vitamin D level is associated with falls among Japanese community-dwelling elderly. J Bone Miner Res. 2008 (in review).
14. Shinkai S, Chaves PHM, Fujiwara Y, Watanabe S, Shibata H, Yoshida H, Suzuki T: Serum beta2-microglobulin, cystacin C, and C-reactive protein for risk stratification of all-cause mortality in a general older population. Arch Inter Med. 2008 (in press).