title: Aging, physical activity, insulin-like growth factor I, and body composition in Guatemalan women.
abstract: Aging is associated with diminished secretion of growth hormone and the major endogenous mediator of growth hormone action, insulin-like growth factor I (IGF-I). Aging is also associated with decreased physical activity. Alterations in body composition characteristic of the aging process (increased fat mass and decreased lean body mass) may be related to the decline in anabolic effects of IGF-I with aging, decreased physical activity, or both. Guatemalan women often maintain a high level of physical activity during aging. The purpose of this study was to determine whether IGF-I concentrations correlated with physical activity level (determined by standardized scoring of a self-report questionnaire) and body composition (determined by bioelectrical impedance analysis) in elderly Guatemalan women. In 112 women aged 20-87 y, we found a progressively lower serum IGF-I with age (r = -0.732). In subjects > 60 y of age, the self-reported activity level was associated with a lower percentage body fat (P < 0.001) but there was no significant relation between physical activity level and either lean body mass or IGF-I. We conclude that there is a significant age-related decline in serum IGF-I concentrations in Guatemalan women, similar to that observed in both men and women in the United States. An increased level of physical activity in the elderly Guatemalan population was associated with reduced body fat but did not modify the expected reduction in circulating IGF-I concentrations that occurs with aging.
authors.affiliation: Center for Studies of Sensory Impairment, Aging and Metabolism, Guatemala City.
authors.forename: J V
authors.initials: JV
authors.lastname: Porch
authors.forename: K
authors.initials: K
authors.lastname: Jain
authors.forename: A
authors.initials: A
authors.lastname: Reilly
authors.forename: C
authors.initials: C
authors.lastname: Valdez
authors.forename: M
authors.initials: M
authors.lastname: Mazariegos
authors.forename: T R
authors.initials: TR
authors.lastname: Ziegler
authors.forename: N
authors.initials: N
authors.lastname: Solomons
authors.forename: R J
authors.initials: RJ
authors.lastname: Smith
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood / Q000378:metabolism* / Q000502:physiology; D001823:Body Composition / Q000502:physiology*; D001824:Body Constitution; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006166:Guatemala; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000378:metabolism; D008875:Middle Aged; D010809:Physical Fitness / Q000502:physiology*; D012044:Regression Analysis; D012424:Rural Population; D014505:Urban Population
chemical_list: D007334:Insulin-Like Growth Factor I