title: Association between muscular strength and intrarenal vascular resistance in middle-aged and older individuals.
abstract: A strategy for the preservation of intrarenal vasculature conditions remains obscure in middle-aged and older individuals without the renal disease. In the present study, we sought to identify whether the maintenance of muscular strength is an effective method of preserving the intrarenal vasculature condition of middle-aged and older individuals. Therefore, we applied a cross-sectional approach for investigating the relationship between muscular strength and the condition of the intrarenal vasculature. In 169 middle-aged and older individuals without renal disease, handgrip strength (HGS) and the renal resistive index (RRI) were measured as the parameters of muscular strength and intrarenal vascular resistance, respectively. The RRI was elevated with aging (rs=0.499, P<0.001) and was inversely correlated with HGS (rs=-0.370, P<0.001). The relationship between RRI and HGS remained significant after the consideration of confounders, including age and various central hemodynamic parameters. Furthermore, when the individuals were divided into four groups according to age (middle-aged or older) and the median HGS values, the RRI exhibited the highest values in the older group with lower HGS values (P<0.001). Our findings indicate that muscular strength as assessed by HGS is independently associated with the RRI (i.e. intrarenal vascular resistance) in middle-aged and older individuals. This finding suggests that the muscular strength may be one of the key factors to preserve the intrarenal vasculature condition.
authors.affiliation: Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan.
authors.forename: Keisei
authors.initials: K
authors.lastname: Kosaki
authors.affiliation: Division of Nephrology and Hypertension, Department of Internal Medicine, St. Marianna University School of Medicine, Kanagawa, Japan; Department of Anatomy, St. Marianna University School of Medicine, Kanagawa, Japan.
authors.forename: Atsuko
authors.initials: A
authors.lastname: Kamijo-Ikemori
authors.affiliation: Division of Nephrology and Hypertension, Department of Internal Medicine, St. Marianna University School of Medicine, Kanagawa, Japan; CMIC Company, Limited, Tokyo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sugaya
authors.affiliation: Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Tanahashi
authors.affiliation: Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kumagai
authors.affiliation: Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan.
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Sawano
authors.affiliation: Research Team for Promoting Independence of the Elderly, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Osuka
authors.affiliation: Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan.
authors.forename: Kiyoji
authors.initials: K
authors.lastname: Tanaka
authors.affiliation: JCHO Tokyo Takanawa Hospital, Tokyo, Japan.
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Kimura
authors.affiliation: Division of Nephrology and Hypertension, Department of Internal Medicine, St. Marianna University School of Medicine, Kanagawa, Japan.
authors.forename: Yugo
authors.initials: Y
authors.lastname: Shibagaki
authors.affiliation: Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan. Electronic address: maeda@taiiku.tsukuba.ac.jp.
authors.forename: Seiji
authors.initials: S
authors.lastname: Maeda
mesh_terms: D000368:Aged; D000375:Aging / Q000502:physiology*; D001794:Blood Pressure; D003430:Cross-Sectional Studies; D005260:Female; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D007564:Japan; D007668:Kidney / Q000098:blood supply / Q000000981:diagnostic imaging; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D012016:Reference Values; D012079:Renal Circulation / Q000502:physiology*; D018608:Ultrasonography, Doppler; D014655:Vascular Resistance / Q000502:physiology*
keywords: Handgrip strength; Renal resistive index; Renal senescence