1.
Supplementary Energy Increases Bone Formation during Arduous Military Training.
O'Leary, TJ, Walsh, NP, Casey, A, Izard, RM, Tang, JCY, Fraser, WD, Greeves, JP
Medicine and science in sports and exercise. 2021;(2):394-403
Abstract
PURPOSE This study aimed to investigate the effect of supplementary energy on bone formation and resorption during arduous military training in energy deficit. METHODS Thirty male soldiers completed an 8-wk military combat course (mean ± SD, age = 25 ± 3 yr, height = 1.78 ± 0.05 m, body mass = 80.9 ± 7.7 kg). Participants received either the habitual diet (control group, n = 15) or an additional 5.1 MJ·d-1 to eliminate the energy deficit (supplemented group, n = 15). Circulating markers of bone formation and resorption, and reproductive, thyroid, and metabolic status, were measured at baseline and weeks 6 and 8 of training. RESULTS Bone-specific alkaline phosphatase decreased in controls (-4.4 ± 1.9 μg·L-1) and increased in the supplemented group (16.0 ± 6.6 μg·L-1), between baseline and week 8 (P < 0.001). Procollagen type 1 N-terminal propeptide increased between baseline and week 6 for both groups (5.6 ± 8.1 μg·L-1, P = 0.005). Beta carboxy-terminal cross-linking telopeptide of type 1 collagen decreased between baseline and week 8 for both groups (-0.16 ± 0.20 μg·L-1, P < 0.001). Prolactin increased from baseline to week 8 for the supplemented group (148 ± 151 IU·L-1, P = 0.041). The increase in adiponectin from baseline to week 8 was higher in controls (4.3 ± 1.8 mg·L-1, P < 0.001) than that in the supplemented group (1.4 ± 1.0 mg·L-1, P < 0.001). Insulin-like growth factor binding protein-3 was lower at week 8 than baseline for controls (-461 ± 395 ng·mL-1, P < 0.001). CONCLUSION The increase in bone-specific alkaline phosphatase, a marker of bone formation, with supplementation supports a role of energy in osteoblastic activity; the implications for skeletal adaptation and stress fracture risk are unclear. The mechanism is likely through protecting markers of metabolic, but not reproductive or thyroid, function.
2.
Effects of vibration training on bone metabolism: results from a short-term bed rest study.
Baecker, N, Frings-Meuthen, P, Heer, M, Mester, J, Liphardt, AM
European journal of applied physiology. 2012;(5):1741-50
Abstract
The absence of mechanical loading leads to a prompt increase in bone resorption measured by bone resorption markers. There is high potential that vibration training can positively influence bone metabolism in immobilized subjects, reduce the increase in osteoclastic activity and increase bone formation processes. We investigated whether vibration training at 20 Hz with an amplitude of 2-4 mm influences bone metabolism during immobilization. Eight male subjects (26.4 ± 4.9 years; 78.1 ± 9.5 kg) performed a 14 day bed rest in 6°-head down tilt (HDT). Subjects received vibration training for 2 × 5 min/day or a control intervention without vibration (crossover design). Calcium excretion and bone resorption markers C-telopeptide (CTX) and N-telopeptide (NTX) were analyzed from 24 h urine samples. Bone formation markers, bone alkaline phosphatase (bAP) and procollagen-N propeptide (PINP) were analyzed from fasting blood samples. Our results show an increase in bone resorption very early during HDT bed rest in both interventions (CTX: p < 0.01; NTX: p < 0.001). Vibration training did not have any different effect on bone resorption markers (CTX: p = 0.10; NTX: p = 0.58), bone formation markers (PINP: p = 0.21; bAP: p = 0.12) and calcium excretion (p < 0.64) compared to the control condition. Mere vibration training with 20 Hz for 2 × 5 min/day does not prevent increase in bone resorption as measured with the described methods in our short-term HDT bed rest.
3.
Efficacy and safety of Menatetrenone-4 postmenopausal Thai women.
Bunyaratavej, N, Penkitti, P, Kittimanon, N, Boonsangsom, P, Bonjongsat, A, Yunoi, S
Journal of the Medical Association of Thailand = Chotmaihet thangphaet. 2001;:S553-9
Abstract
Clinical and comparative study of the efficacy and adverse events of Menatetrenone-4. The control group (n=40) received elemental calcium carbonate 800 mg/day and the Menatetrenone-4 treated group received elemental calcium carbonate 800 mg/day plus vitamin K2 45 mg/day (n=43). The vitamin K2 treated group showed a marked decrease of undercarboxylated osteocalcin at 2 weeks, six months (51.52% p=0.0001) and twelve months (87.26% p=0.0001) compared to the calcium treated group. At the end of the sixth and twelve months both groups did not increase bone mass of the hip but the vitamin K2 treated group increased 0.6 per cent of bone mass of the lumbar spine and decreased bone resorption 65.42 per cent (p=0.0001) compared to the calcium treated group. The calcium treated group was switched to the vitamin K2 treated group at the end of six months and showed a decrease of the level of undercarboxylated osteocalcin the same as the former vitamin K2 treated group. The adverse events were 2 cases of mild skin rash which subsided after cessation of medication.
4.
Bone mineral density in lung-transplant recipients before and after graft: prevention of lumbar spine post-transplantation-accelerated bone loss by pamidronate.
Trombetti, A, Gerbase, MW, Spiliopoulos, A, Slosman, DO, Nicod, LP, Rizzoli, R
The Journal of heart and lung transplantation : the official publication of the International Society for Heart Transplantation. 2000;(8):736-43
Abstract
BACKGROUND Lung-transplant recipients are at risk of osteoporosis. They may have low bone mass even before posttransplantation immunosuppressive therapy. We studied bone mineral density (BMD) before and after lung transplantation and compared the efficacy of antiresorptive therapies to calcium and vitamin D supplementation. METHODS Areal BMD was assessed in 42 patients awaiting lung transplantation and measured again after surgery at 6 (n = 29), and at 12 months (n = 20). Nineteen patients received antiresorptive therapy (30 mg pamidronate IV every 3 months (n = 14), or hormonal replacement therapy (n = 5)), and 10 patients received only calcium and vitamin D supplements. RESULTS Mean age- and gender-adjusted lumbar spine (LS) and femoral neck (FN) BMD was significantly decreased prior to transplantation (- 0.6 +/- 0.2, p< 0.01, and - 1.5 +/- 0.2 standard deviation, p < 0.001, respectively). At that time, 29% were osteoporotic (T-score < - 2.5 below the peak bone mass), while 55% were below - 1.0 T-score. Antiresorptive therapy decreased the rate of LS bone loss during the first 6 months and led to a significant increase of BMD at 1 year, with LS changes of + 0.2 +/- 0.1 vs - 0.4 +/- 0.1 Z-score in the calcium-vitamin D group (p< 0.002), and + 0.2 +/- 0.1 vs - 0.04 +/- 0.1 for FN (NS). One out of 20 patients experienced clinically evident fractures during antiresorptive therapy, and 3 out of 12 in the calcium-vitamin D group. CONCLUSION A significant proportion of patients awaiting lung transplantation was osteoporotic or osteopenic. Antiresorptive therapy (pamidronate or hormone-replacement therapy (HRT)) prevented accelerated LS bone loss after graft.