To determine the body composition differences across age, 133 men with chronic spinal cord injury (SCI) (66 with tetraplegia, 67 with paraplegia) were compared with an age-, height-, and ethnicity-matched able-bodied male reference population (n = 100) using two different dual-energy X-ray absorptiometry densitometers. The effects of duration of injury, level, and completeness of lesion were analyzed in the SCI population. Independent of age, total body and regional lean mass were lower and fat mass was higher in persons with SCI compared with controls. The SCI group was 13 +/- 1% (means +/- SE) fatter per unit of body mass index (kg/m2) compared with the control group (P < 0.0001). Advancing age was strongly associated with less lean mass and greater adiposity in those with SCI, whereas it was mildly related in the controls. Total body and regional arm and trunk, but not leg, lean tissues were lower in subjects with SCI, across all ages, than in the controls. In summary, persons with SCI were fatter for any body mass index and demonstrated significantly less lean and more adipose tissues for any given age compared with controls.

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OBJECTIVE -Of patients who are prescribed metformin, 10-30% have evidence of reduced vitamin B 12 absorption. B 12 -intrinsic factor complex uptake by ileal cell surface receptors is known to be a process dependent on calcium availability. Metformin affects calciumdependent membrane action. The objective of this study was to determine the magnitude and mechanism of the reduction in serum vitamin B 12 after metformin administration. RESEARCH DESIGN AND METHODS-A comparative study design was employed using 2 groups (metformin and control). A total of 21 patients with type 2 diabetes received sulfonylurea therapy; 14 of these 21 patients were switched to metformin. Monthly serum total vitamin B 12 measurements and holotranscobalamin (holoTCII) (B 12 -TCII) were performed. After 3 months of metformin therapy, oral calcium supplementation was administered.RESULTS -Serial serum vitamin B 12 determinations revealed a similar decline in vitamin B 12 and holoTCII. Oral calcium supplementation reversed the metformin-induced serum holoTCII depression.CONCLUSIONS -Patients receiving metformin have diminished B 12 absorption and low serum total vitamin B 12 and TCII-B 12 levels because of a calcium-dependent ileal membrane antagonism, an effect reversed with supplemental calcium.

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Individuals with SCI have an increased prevalence of abnormalities in carbohydrate and lipid metabolism because of immobilization, muscle atrophy and relative adiposity. In those with SCI, an inverse relationship has been reported between serum high-density lipoprotein (HDL) cholesterol values and abdominal circumference, and a direct relationship between serum triglycerides levels and abdominal circumference. Persons with SCI have lower serum HDL cholesterol levels than able-bodied controls. A higher prevalence of insulin resistance and diabetes mellitus, as well as an earlier occurrence of coronary heart disease (CHD), has been reported in persons with SCI than in the general population. Recently, a higher prevalence and greater degree of coronary artery calcification by electron beam computerized tomography has been demonstrated in persons with SCI, even if matched with the able-bodied population for age, gender, ethnicity and conventional risk factors for CHD. Knowledge of relative risk of CHD in persons with SCI is important for appropriate intervention strategies. The conventional risk factors for CHD were determined in veterans with SCI to assign risk to determine target low-density lipoprotein cholesterol levels for therapeutic intervention. Limitations of conventional guidelines when applied to the SCI population should be appreciated. Conventional risk factors for CHD should be identified and treated in individuals with SCI, according to current standards of care.

To determine the effect of paralysis on body composition, eight pairs of male monozygotic twins, one twin in each pair with paraplegia, were studied by dual-energy X-ray absorptiometry. Significant loss of total body lean tissue mass was found in the paralyzed twins compared with their able-bodied co-twins: 47.5 +/- 6. 7 vs. 60.1 +/- 7.8 (SD) kg (P < 0.005). Regionally, arm lean tissue mass was not different between the twin pairs, whereas trunk and leg lean tissue masses were significantly lower in the paralyzed twins: -3.0 +/- 3.3 kg (P < 0.05) and -10.1 +/- 4.0 kg (P < 0.0005), respectively. Bone mineral content of the total body and legs was significantly related to lean tissue mass in the able-bodied twins (R = 0.88 and 0.98, respectively) but not in the paralyzed twins. However, the intrapair difference scores for bone and lean tissue mass were significantly related (R = 0.80 and 0.81, respectively). The paralyzed twins had significantly more total body fat mass and percent fat per unit body mass index than the able-bodied twins: 4.8 kg (P < 0.05) and 7 +/- 2% (P < 0.01). In the paralyzed twins, total body lean tissue was significantly lost (mostly from the trunk and legs), independent of age, at a rate of 3.9 +/- 0.2 kg per 5-yr period of paralysis (R = 0.87, P < 0.005). Extreme disuse from paralysis appears to contribute to a parallel loss of bone with loss of lean tissue in the legs. The continuous lean tissue loss may represent a form of sarcopenia that is progressive and accelerated compared with that in ambulatory individuals.

Study design: Oral glucose tolerance testing was performed prospectively in 201 subjects with spinal cord injury (SCI). The dependent variables included the values from the oral glucose tolerance test (glucose and insulin) and diagnostic classi®cation (i.e., diabetes mellitus, impaired glucose tolerance, normal glucose tolerance); the independent variables consisted of study group, gender, ethnic group, age, age at onset of SCI, duration of injury, and anthropometric measurements. Objective: To determine the potential e ects of level and completeness of SCI on oral glucose tolerance testing. In addition, the e ects of gender ethnicity, age, age at onset of SCI, duration of injury, and anthropometric measurements on glucose tolerance were investigated. Setting: Subjects with chronic SCI were recruited during their annual physical examination at the Comarr Spinal Injury Clinic at Rancho Los Amigos Medical Center, Downey, California. Methods: An oral 75 g glucose load was administered after an overnight fast. Serum glucose was determined by autoanalyzer and plasma insulin levels, by radioimmunoassay. The results are reported as mean plus or minus standard error of the mean (mean+SEM). Analysis of variance (ANOVA) applying a Sche e' post hoc F ratio was used for the continuous variables. Chi-squared analyses were performed to determine di erences between the groups and among the subgroups for per cent distribution. Linear regression analyses were performed between variables of interest. Stepwise regression analyses were used to predict peak serum glucose concentration and peak plasma insulin level from potential determinants. Results: The total group consisted of 169 men with a mean age of 38+0.80 (range=20 ± 73) years and 32 women with a mean age of 44+2.13 (range =20 ± 72) years. The distribution by ethnicity for the total group with SCI consisted of 114 (57%) Latino, 54 (27%) white, and 28) 14%) African American individuals. There was no signi®cant di erence in ethnic distribution among the subgroups for neurological de®cit. Subjects were grouped by tetraplegia (Tetra; n=81) or paraplegia (Para; n=120) and by subgroup for degree of neurological de®cit: complete Tetra (n=56), incomplete Tetra (n=25), complete Para (n=84), and incomplete Para (n=36). Of the total group, 27 subjects (13.4%) had diabetes mellitus and 56 (28.8%) had impaired glucose tolerance. Signi®cantly more subjects in the complete Tetra group were classi®ed with a disorder of carbohydrate metabolism than in the other neurological de®cit subgroups (73 vs 44%, 24% and 31%, respectively for level of decreasing neurological de®cit; X 2 =36.9, P50.0001). The complete Tetra group had signi®cantly higher serum glucose concentrations at 60 min, 90 min, and 120 min and serum insulin concentration at 90 and 120 min compared with the other neurological subgroups (P50.05 for each time point). No di erences for plasma glucose were evident between men and women, however, plasma insulin levels were signi®cantly higher for men at the intermediate time points (30...

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