Aging in humans: a continuous 20-year study of physiologic and dietary parameters.

Flynn, Margaret; Nolph, G B; Baker, A S; Krause, G. F.

doi:10.1080/07315724.1992.10718265

Cited by 51 publications

(29 citation statements)

References 27 publications

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“…Subjects are current participants in the Longitudinal Aging Study, initiated in 1969 and continuing through the present at the University of Missouri-Columbia. 12 The study population consisted primarily of University of Missouri faculty and staff who were physically active and in apparent good health, with no evidence of decreased intrinsic factor secretion or gastrointestinal B12 malabsorption. The project was approved by the University of Missouri-Columbia Institutional Review Board and all participants provided their informed consent.…”

Section: Study Design Subjectsmentioning

confidence: 99%

Transcobalamin II 775G>C polymorphism and indices of vitamin B12 status in healthy older adults

Miller

Ramos

Garrod

et al. 2002

Blood

112

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A common polymorphism (775G>C) in the vitamin B12 transport protein, transcobalamin II (TCII), has been identified in which proline replaces arginine at codon 259. We determined the influence of TCII genotype on indices of B12 status, including total serum B12, the amount of B12 bound to TCII (holoTCII), methylmalonic acid, and homocysteine, in 128 healthy older adults (ages 40-88 years). Mean total B12 and homocysteine concentrations were not significantly different among the 3 genotypes. Mean holoTCII concentration was significantly higher in those subjects homozygous for the proline form of TCII (PP) compared with those homozygous for the arginine form (RR) and heterozygotes (PR) (P < .006). In addition, mean methylmalonic acid concentrations were significantly lower in the PP and PR groups compared with the RR group (P < .02). The PP genotype may be more efficient in delivering B12 to tissues, resulting in enhanced B12 functional status. TCII genotype may thus influence susceptibility to B12 deficiency. IntroductionThe serum protein, transcobalamin II (TCII), transports vitamin B12 (B12) from the ileum to the tissues. The B12-TCII complex (holoTCII) is then taken up into cells by receptor-mediated endocytosis. In the 1970s and 1980s, 2 research groups independently identified distinct isopeptide forms of TCII by polyacrylamide gel electrophoresis 1,2 and isoelectric focusing. 3 More recently, DNA sequencing has revealed that the isopeptide forms of TCII are the result of single nucleotide polymorphisms. [4][5][6] The most common polymorphism in white populations is a G-to-C substitution at base position 775 (775GϾC), which results in the replacement of proline with arginine at codon 259. Recently, the potential influence of the 775GϾC polymorphism on indices of vitamin B12 status has been investigated. Persons homozygous for the proline form of the protein (PP) tend to have higher holoTCII but similar total serum B12 concentrations compared with those homozygous for the arginine form (RR). [7][8][9][10][11] One group has found that homocysteine, a functional indicator of B12 status, is higher in heterozygous persons (PR) than in PP and RR persons, 8,11 but this finding was not confirmed. 9,10 Notably, the relationship between TCII genotype and methylmalonic acid, potentially a more specific indicator of B12 status than homocysteine, has not been reported. Therefore, we assessed the relationship between 775GϾC TCII genotype and methylmalonic acid and between total B12, holoTCII, and homocysteine in a cohort of healthy older adults. Study design SubjectsThe study sample consisted of 108 men and 20 women (mean age, 67 years; range, 40-88 years). Subjects are current participants in the Longitudinal Aging Study, initiated in 1969 and continuing through the present at the University of Missouri-Columbia. 12 The study population consisted primarily of University of Missouri faculty and staff who were physically active and in apparent good health, with no evidence of decreased intrinsic factor secretion or gastroi...

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Section: Study Design Subjectsmentioning

confidence: 99%

Transcobalamin II 775G>C polymorphism and indices of vitamin B12 status in healthy older adults

Miller

Ramos

Garrod

et al. 2002

Blood

112

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“…Changes in height, weight and BMI with aging in cross sectional studies may be the combined result of age and cohort effects as well as selective survival. Longitudinal studies with long-term follow-up on individual level are required to isolate the age effect on these anthropometric parameters.Most of the studies on longitudinal height change were performed in small samples with <500 individuals per gender (Chumlea et al, 1988;Flynn et al, 1992;Galloway et al, 1990;Miall et al, 1967; Par ızkov a and Eiselt, 1971). Some data from larger cohorts are available for the US (Borkan et al, 1983;Cline et al, 1989;Sorkin et al, 1999a), Australia (Chandler and Bock, 1991), and Sweden with data only for women (Noppa et al, 1980).…”

mentioning

confidence: 98%

Change in Height, Weight, and body mass index: Longitudinal data from Austria

Peter

Fromm

Klenk

et al. 2014

American J Hum Biol

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“…Significant changes in body composition occur with aging [1][2][3] and influence overall health. Increases of total and abdominal fat masses (FM) have been associated with cardiovascular and metabolic diseases [4,5], while the decline of fat-free mass (FFM) may impair muscle strength, immunity, and increase morbidity and mortality [6,7].…”

Section: Introductionmentioning

confidence: 99%

Comparison of Four Bioelectrical Impedance Analysis Formulas in Healthy Elderly Subjects

Genton¹,

Karsegard²,

Kyle³

et al. 2001

Gerontology

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Background: Changes of body composition occur with aging and influence health status. Thus accurate methods for measuring fat-free mass (FFM) in the elderly are essential. Objective: The purpose of this study was to compare FFM obtained by three bioelectrical impedance analysis (BIA) published formulas specific for the elderly and one equation intended for all age groups, with FFM derived from dual-energy X-ray absorptiometry (FFM_DXA), in healthy elderly subjects. Methods: Healthy Caucasian subjects over 65 years (106 women, age 75 ± 6.2, body mass index 25.2 ± 4.1 and 100 men, age 74.6 ± 6.6, body mass index 25.8 ± 3.0) were measured by DXA (Hologic QDR-4500) and BIA (Xitron, 50 kHz). FFM_BIA was calculated by the published formulas of Deurenberg, Baumgartner, Roubenoff and Kyle and compared to FFM_DXA by a Bland-Altman analysis. Results: The Deurenberg and Roubenoff BIA formulas underestimated FFM compared to DXA by –7.1 and –2.9 kg in women and –6.7 and –2.3 kg in men, respectively. The Baumgartner formula overestimated FFM by 4.3 kg in women and 1.4 kg in men. The Kyle formula showed differences of 0.0 kg in women and 0.2 kg in men, and the limits of agreement of FFM_{BIA (Kyle)} relative to FFM_DXA were –3.3 and +3.3 kg for women and –3.8 and +4.3 kg for men. Conclusion: The Kyle BIA formula accurately predicts FFM in elderly Swiss subjects between 65 and 94 years, with a body mass index of 17 to 34.9 kg/m². The other BIA formulas developed especially for the elderly are not valid in this population.

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Aging in humans: a continuous 20-year study of physiologic and dietary parameters.

Cited by 51 publications

References 27 publications

Transcobalamin II 775G>C polymorphism and indices of vitamin B12 status in healthy older adults

Transcobalamin II 775G>C polymorphism and indices of vitamin B12 status in healthy older adults

Change in Height, Weight, and body mass index: Longitudinal data from Austria

Comparison of Four Bioelectrical Impedance Analysis Formulas in Healthy Elderly Subjects

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Aging in humans: a continuous 20-year study of physiologic and dietary parameters.

Cited by 51 publications

References 27 publications

Transcobalamin II 775G&gt;C polymorphism and indices of vitamin B12 status in healthy older adults

Transcobalamin II 775G&gt;C polymorphism and indices of vitamin B12 status in healthy older adults

Change in Height, Weight, and body mass index: Longitudinal data from Austria

Comparison of Four Bioelectrical Impedance Analysis Formulas in Healthy Elderly Subjects

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Transcobalamin II 775G>C polymorphism and indices of vitamin B12 status in healthy older adults

Transcobalamin II 775G>C polymorphism and indices of vitamin B12 status in healthy older adults