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Bloomfield SA, Swift SN, Metzger CE, Baek K, De Souza MJ, Lenfest S, Shirazi-Fard Y, Hogan HA. Exercise training modifies the bone and endocrine response to graded reductions in energy availability in skeletally mature female rodents. Front Endocrinol (Lausanne) 2023; 14:1141906. [PMID: 37455901 PMCID: PMC10338226 DOI: 10.3389/fendo.2023.1141906] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 05/23/2023] [Indexed: 07/18/2023] Open
Abstract
Introduction Reductions in energy availability leading to weight loss can induce loss of bone and impact important endocrine regulators of bone integrity. We sought to elucidate whether endurance exercise (EX) can mitigate bone loss observed in sedentary (SED) skeletally mature rodents subjected to graded energy deficits. Methods Female virgin rats (n=84, 5-mo-old; 12/group) were randomized to baseline controls and either sedentary (SED) or exercise (EX) conditions, and within each exercise status to adlib-fed (ADLIB), or moderate (MOD) or severe (SEV) energy restriction diets for 12 weeks. Rats assigned to EX groups performed treadmill running to increase weekly energy expenditure by 10%. MOD-ER-SED, SEV-ER-SED, MOD-ER-EX and SEV-ER-EX were fed modified AIN93M diets with 20%, 40% 10%, and 30% less energy content, respectively, with 100% of all other nutrients provided. Results Energy availability (EA) was effectively reduced by ~14% and ~30% in the MOD-ER and SEV-ER groups, respectively. MOD-ER for 12 weeks resulted in few negative impacts on bone and, except for serum leptin in MOD-ER-SED rats, no significant changes in endocrine factors. By contrast, SEV-ER in SED rats resulted in significantly lower total body and femoral neck bone mass, and reduced serum estradiol, IGF-1 and leptin. EX rats experiencing the same reduction in energy availability as SEV-ER-SED exhibited higher total body mass, lean mass, total BMC, and higher serum IGF-1 at the end of 12 weeks. Bone mechanical properties at 3 bone sites (mid-femur, distal femur, femoral neck) were minimally impacted by ER but positively affected by EX. Discussion These findings indicate that combining increased EX energy expenditure with smaller reductions in energy intake to achieve a targeted reduction in EA provides some protection against loss of bone mass and lean mass in skeletally mature female rats, likely due to better preservation of circulating IGF-1, and that bone mechanical integrity is not significantly degraded with either moderate or severe reduced EA.
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Affiliation(s)
- Susan A. Bloomfield
- Bone Biology Laboratory, Department of Kinesiology & Sport Management, Texas A&M University, College Station, TX, United States
- Bone Biology Laboratory, Department of Nutrition, Texas A&M University, College Station, TX, United States
| | - Sibyl N. Swift
- Bone Biology Laboratory, Department of Nutrition, Texas A&M University, College Station, TX, United States
| | - Corinne E. Metzger
- Bone Biology Laboratory, Department of Kinesiology & Sport Management, Texas A&M University, College Station, TX, United States
| | - Kyunghwa Baek
- Bone Biology Laboratory, Department of Nutrition, Texas A&M University, College Station, TX, United States
| | - Mary Jane De Souza
- Women’s Health and Exercise Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, PA, United States
- Women’s Health and Exercise Laboratory, Department of Physiology, The Pennsylvania State University, University Park, PA, United States
| | - Scott Lenfest
- Bone Mechanics Laboratory, Department of Mechanical Engineering, Texas A&M University, College Station, TX, United States
| | - Yasaman Shirazi-Fard
- Bone Mechanics Laboratory, Department of Mechanical Engineering, Texas A&M University, College Station, TX, United States
| | - Harry A. Hogan
- Bone Mechanics Laboratory, Department of Mechanical Engineering, Texas A&M University, College Station, TX, United States
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Soltani S, Hunter GR, Kazemi A, Shab-Bidar S. The effects of weight loss approaches on bone mineral density in adults: a systematic review and meta-analysis of randomized controlled trials. Osteoporos Int 2016; 27:2655-2671. [PMID: 27154437 DOI: 10.1007/s00198-016-3617-4] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 04/26/2016] [Indexed: 12/15/2022]
Abstract
UNLABELLED We assessed the impact of weight loss strategies including calorie restriction and exercise training on BMD in adults using a systematic review of randomized controlled trials. Weight reduction results in reduced BMD at the hip, but has less effect on the spine. Both calorie restriction and a combination of calorie restriction and exercise result in a decrease in hip bone density, whereas weight loss response to exercise training without dietary restriction leads to increased hip BMD. INTRODUCTION Findings are not consistent on the effect of weight loss on bone mineral density (BMD). We conducted a systematic review on the randomized controlled trials to assess the effect of weight loss strategies, including calorie restriction and exercise programs on BMD in adults. METHODS A structured and comprehensive search of MEDLINE and EMBASE databases was undertaken up to March 2016. Study-specific mean differences (MD) were pooled using a random-effects model. Subgroup analysis and meta-regression were used to find possible sources of between-study heterogeneity. RESULTS Thirty-two randomized controlled trials met predetermined inclusion criteria. The meta-analysis revealed no significant difference on total BMD (MD 0.007, 95 % CI -0.020-0.034, p = 0.608). In contrast, the pooled data of studies showed a significant effect of weight loss on hip BMD (MD -0.008, 95 % CI -0.09 to -0.006 g/cm(2), p < 0.001) and also lumbar spine BMD (MD -0.018 g/cm(2), 95 % CI -0.019 to -0.017, p < 0.001). BMD in the hip site decreased after more than 4 months, especially in those who were obese. Moreover, calorie restriction interventions longer than 13 months showed a significant decreased in lumbar spine BMD. CONCLUSION Weight loss led to significant decreases at the hip and lumbar spine BMD but not at the total. Weight loss response following calorie restriction resulted in a decrease in hip and lumbar spine bone density especially more than 1 year; whereas an exercise-induced weight loss did not.
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Affiliation(s)
- S Soltani
- Department of Nutrition, School of Public Health, Iran University of Medical Sciences, Hemaat Highway, 1449614535, Tehran, Iran
| | - G R Hunter
- Department of Human Studies School of Education, University of Alabama at Birmingham, EB 205 1720 2nd Ave South, Birmingham, AL, 34294-1250, USA
| | - A Kazemi
- Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, P. O. Box 14155/6117, Amir Abad, Keshavarz Boulevard, Tehran, Iran
| | - S Shab-Bidar
- Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, P. O. Box 14155/6117, Amir Abad, Keshavarz Boulevard, Tehran, Iran.
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Park J, Omi N. DHEA administration has limited effect onintestinal Ca absorption in ovariectomized rats. J Exerc Nutrition Biochem 2014; 18:333-7. [PMID: 25671199 PMCID: PMC4322023 DOI: 10.5717/jenb.2014.18.4.333] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 11/24/2014] [Indexed: 11/18/2022] Open
Abstract
[Purpose] The effect of dehydroepiandrosterone (DHEA) administration on intestinal Calcium (Ca) absorption in estrogen deficiency state has not been studied yet. We examined the bone mineral content (BMC) of lumbar spine and Ca balance such as intestinal Ca absorption and Ca accumulation in ovariectomized (OVX) rats after 8 weeks of DHEA administration. [Methods] Seventeen female Sprague-Dawley rats, 6 weeks old, were randomized into two groups: OVX control rats (OC, n = 8) and OVX rats with DHEA treatment (OD, n = 9). DHEA was administered to the OD group intraperitoneally at 20 mg DHEA/kg body weight for 8 weeks while the OC group was treated with vehicle only. [Results] The BMC normalized by body weight of the lumbar spine (trabecular-abundant region) in the OD group was found to be significantly higher compared to that in the OC group. The femoral wet weight normalized by body weight in the OD group was significantly higher compared to that in the OC group. The intestinal Ca absorption, rate of intestinal Ca absorption, Ca accumulation, and rate of Ca accumulation decreased from the 4th and 5th of the experimental diet period to the end of the experimental period, but interaction of time and group was not observed. In both periods, all parameters did not differ between the groups. [Conclusion] The present study confirmed the positive effect of DHEA on trabecular bone mass in ovariectomized rats. On the other hand, DHEA administration might have limited the impact on intestinal Ca absorption in estrogen deficiency state.
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Affiliation(s)
- Jonghoon Park
- Department of Physical Education, Konkuk University, Seoul, Korea
| | - Naomi Omi
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan
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Foo JP, Polyzos SA, Anastasilakis AD, Chou S, Mantzoros CS. The effect of leptin replacement on parathyroid hormone, RANKL-osteoprotegerin axis, and Wnt inhibitors in young women with hypothalamic amenorrhea. J Clin Endocrinol Metab 2014; 99:E2252-8. [PMID: 25148234 PMCID: PMC5393498 DOI: 10.1210/jc.2014-2491] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
CONTEXT Recombinant leptin (metreleptin) treatment restores bone mineral density in women with hypothalamic amenorrhea (HA), a condition characterized by hypoleptinemia, which has adverse impact on bone health. OBJECTIVE The objective of the study was to investigate how metreleptin exerts its positive effect on bone metabolism in humans. DESIGN This was a randomized, double-blinded, placebo-controlled study. SETTING The study was conducted at Beth Israel Deaconess Medical Center (Boston, Massachusetts). PATIENTS AND INTERVENTIONS Women (n = 18) with HA and hypoleptinemia for at least 6 months were randomized to receive either metreleptin or placebo for 36 weeks. Serum samples were obtained at baseline and 12, 24, and 36 weeks of treatment. MAIN OUTCOME MEASURES Circulating levels of leptin, intact PTH (iPTH), receptor activator of nuclear factor-κB ligand (RANKL), osteoprotegerin (OPG), sclerostin, dickkopf-1, and fibroblast growth factor-23. RESULTS Metreleptin administration significantly increased leptin levels throughout the treatment period (P = .001). iPTH decreased over the 36 weeks of treatment (P = .01). There was a trend toward a decrease in serum RANKL and increase in serum OPG in the metreleptin-treated group. The RANKL to OPG ratio was significantly decreased within the metreleptin (P = .04) but not the placebo group. Metreleptin had no effect on serum sclerostin, dickkopf-1, and fibroblast growth factor-23. CONCLUSIONS Metreleptin treatment over 36 weeks decreases iPTH and RANKL to OPG ratio levels in hypoleptinemic women with HA.
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Affiliation(s)
- Joo-Pin Foo
- Division of Endocrinology, Diabetes, and Metabolism (J.-P.F., S.A.P., S.C., C.S.M.), Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215; Department of Endocrinology (A.D.A.), 424 General Military Hospital, 54006 Thessaloniki, Greece; and Section of Endocrinology (C.S.M.), Boston Veterans Affairs Healthcare System, Harvard Medical School, Boston, Massachusetts 02130
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Lerchbaum E. Vitamin D and menopause—A narrative review. Maturitas 2014; 79:3-7. [DOI: 10.1016/j.maturitas.2014.06.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 06/05/2014] [Indexed: 01/23/2023]
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Ahn H, Seo DH, Kim HS, Choue R. Calorie restriction aggravated cortical and trabecular bone architecture in ovariectomy-induced estrogen-deficient rats. Nutr Res 2014; 34:707-13. [PMID: 25172380 DOI: 10.1016/j.nutres.2014.07.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 06/28/2014] [Accepted: 07/04/2014] [Indexed: 10/25/2022]
Abstract
We hypothesized that calorie restriction (CR) and estrogen deficiency (ovariectomy [OVX]) would aggravate bone biomarkers and structural parameters in rats. Seven-week-old female Sprague-Dawley rats were randomized to sham-operated groups and fed either an ad libitum diet (SHAM-AL) or a CR diet (SHAM-CR); ovariectomy-operated groups were fed an ad libitum diet (OVX-AL) or a CR diet (OVX-CR). For 8 weeks, the OVX-AL and SHAM-AL groups were fed the same diet, whereas CR groups were fed a diet containing 50% fewer calories. Bone-related biomarkers and structural parameters (OC; deoxypyridinoline [DPD]; N-terminal telopeptide, NTx; architecture and mineralization; and microcomputed tomography images) were analyzed at the end of the experiment. The serum OC levels of calorie-restricted groups (SHAM-CR and OVX-CR) were significantly lower than those of the AL groups (SHAM-AL and OVX-AL) (P < .05). Urinary DPD levels of calorie-restricted and ovariectomized groups were higher than those of their counterparts (P < .05), whereas urinary NTx levels of calorie-restricted groups were higher than those of AL groups (P < .05). In regard to trabecular bone, the calorie-restricted and ovariectomized groups had lower values of bone volume to total volume, trabecular number, and bone mineral density, but higher values of trabecular separation than those of their counterparts (P < .05). Regarding cortical bone, the calorie-restricted groups had reduced values of bone volume, mean polar moment of inertia, and cortical thickness compared to the AL groups (P < .05). In conclusion, severe CR with or without OVX during the growth period in rats is equally detrimental to bone; CR has detrimental effects on trabecular and cortical bone; and estrogen deficiency only had an effect on trabecular bone.
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Affiliation(s)
- Hyejin Ahn
- Department of Medical Nutrition, Kyung Hee University, Yongin, Korea
| | - Dong-Hyun Seo
- Department of Biomedical Engineering, Yonsei University, Wonju, Korea
| | - Han Sung Kim
- Department of Biomedical Engineering, Yonsei University, Wonju, Korea
| | - Ryowon Choue
- Department of Medical Nutrition, Kyung Hee University, Yongin, Korea; Research Institute of Medical Nutrition, Kyung Hee University, Seoul, Korea.
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Shapses SA, Sukumar D, Schneider SH, Schlussel Y, Sherrell RM, Field MP, Ambia-Sobhan H. Vitamin D supplementation and calcium absorption during caloric restriction: a randomized double-blind trial. Am J Clin Nutr 2013; 97:637-45. [PMID: 23364004 PMCID: PMC3578405 DOI: 10.3945/ajcn.112.044909] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Weight loss (WL) is associated with a decrease in calcium absorption and may be one mechanism that induces bone loss with weight reduction. OBJECTIVE Because vitamin D supplementation has been shown to increase true fractional calcium absorption (TFCA), the goal of this study was to examine the effect of vitamin D during WL or weight maintenance (WM). DESIGN A randomized, placebo-controlled, double-blind 6-wk study was conducted in 82 postmenopausal women [BMI (in kg/m(2); ±SD): 30.2 ± 3.7] with 25-hydroxyvitamin D [25(OH)D] concentrations <70 nmol/L during either WL or WM. All women were given 10 μg vitamin D(3)/d and 1.2 g Ca/d and either weekly vitamin D(3) (375 μg) or a placebo equivalent to 63 μg (2500 IU)/d and 10 μg (400 IU)/d, respectively. We measured TFCA with the use of dual-stable isotopes, 25(OH)D, parathyroid hormone, estradiol, calcitriol, and urinary calcium at baseline and 6 wk in weight loss and vitamin D(3)-supplementation (WL-D; n = 19), weight maintenance and vitamin D(3)-supplementation (WM-D; n = 20), weight loss and placebo (n = 22), and weight maintenance and placebo (n = 21) groups. RESULTS WL groups lost 3.8 ± 1.1% of weight with no difference between vitamin D(3) supplementation and the placebo. The rise in serum 25(OH)D was greatest in the WL-D group (19.8 ± 14.5 nmol/L) compared with in WM-D (9.1 ± 10.3 nmol/L) and placebo groups (1.5 ± 10.9 nmol/L). TFCA increased with vitamin D(3) supplementation compared with placebo treatment (P < 0.01) and decreased during WL compared with WM. Serum 25(OH)D or 1,25-dihyroxyvitamin D did not correlate with TFCA. CONCLUSION These data show that vitamin D supplementation increases TFCA and that WL decreases TFCA and suggest that, when calcium intake is 1.2 g/d, either 10 or 63 μg vitamin D/d is sufficient to maintain the calcium balance. This trial was registered at clinicaltrials.gov as NCT00473031.
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Affiliation(s)
- Sue A Shapses
- Department of Nutritional Sciences and Institute of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ, USA.
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Shapses SA, Sukumar D, Schneider SH, Schlussel Y, Brolin RE, Taich L. Hormonal and dietary influences on true fractional calcium absorption in women: role of obesity. Osteoporos Int 2012; 23:2607-14. [PMID: 22282301 PMCID: PMC4016952 DOI: 10.1007/s00198-012-1901-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 11/18/2011] [Indexed: 10/14/2022]
Abstract
UNLABELLED The goal in this study was to examine the hormonal and dietary predictors of true fractional Ca absorption (TFCA) in adult women and to determine whether TFCA differs due to body weight. Results showed that TFCA is higher in obese individuals and dietary fat, estradiol, and 1,25-dihydroxy vitamin D are the most significant positive predictors of TFCA in adult women. INTRODUCTION Calcium absorption is an important determinant of calcium balance and is influenced by several factors. Previous studies have identified that age, intake of protein, fat and fiber, and hormones such as 1, 25-dihyroxyvitamin D (1,25(OH)(2)D(3)) influence absorption. The determinants of TFCA using the double isotope method, the gold standard estimate of absorption, have not been examined previously in adult women nor has the role of obesity been addressed. METHODS In this study, we examined the hormonal and dietary predictors of TFCA in adult women with a wide range of age, body weights, and nutrient intake. TFCA was measured using dual stable isotope ((42)Ca and (43)Ca) technique. Serum was analyzed for bone-regulating hormones, and dietary information was obtained through food records. The independent dietary factors and hormonal predictors (25-hydroxyvitamin D, 1,25(OH)(2)D(3), parathyroid hormone, and estradiol) of TFCA were analyzed using multiple regression analysis. RESULTS Two hundred twenty-nine women aged 54 ± 11 years old (24-75 years) and with BMI of 31 ± 7.0 kg/m(2) were eligible and were categorized into tertiles of body mass index (BMI) into leaner, overweight, and obese. In the entire group of women, total fat intake, estradiol, and 1,25(OH)(2)D(3) are significant positive predictors (p < 0.05). As expected, age is a significant negative predictor of TFCA (R (2) = 26%). TFCA is higher in obese women compared to non-obese women (p < 0.05). CONCLUSION Together, these data show that dietary fat is the most significant positive predictor of TFCA which may have implications for dietary intake for non-obese individuals who are more likely to have lower and potentially compromised Ca absorption.
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Affiliation(s)
- S A Shapses
- Department of Nutritional Sciences, Rutgers University, 96 Lipman Drive, New Brunswick, NJ 08901-8525, USA.
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Reinehr T, Roth CL. A new link between skeleton, obesity and insulin resistance: relationships between osteocalcin, leptin and insulin resistance in obese children before and after weight loss. Int J Obes (Lond) 2010; 34:852-8. [PMID: 20065970 DOI: 10.1038/ijo.2009.282] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND The skeleton is regarded recently as an endocrine organ that affects energy metabolism. However, there are very limited data available concerning the relationships between the osteoblast-derived hormone osteocalcin, weight status, adiponectin and leptin in obese humans, especially in children. METHODS We analyzed osteocalcin, adiponectin, leptin and insulin resistance (IR) index homeostasis model assessment (HOMA) in 60 obese and 19 age- and gender-matched normal weight children. Furthermore, these parameters were determined in 60 obese children after participating in an outpatient 1-year lifestyle intervention based on exercise, behavior and nutrition therapy. RESULTS Sixty obese children had significantly lower osteocalcin levels (26.8+/-0.8 ng ml(-1)) than 19 normal weight controls (32.2+/-2.3 ng ml(-1)). Boys (29.9+/-1.1 ng ml(-1)) showed significantly (P=0.046) higher osteocalcin levels compared with girls (26.4+/-1.2 ng ml(-1)). In stepwise multiple linear regression analysis adjusted for age, gender and pubertal stage, osteocalcin was significantly negatively related to leptin and HOMA, but not to adiponectin. Changes of osteocalcin in the course of 1 year correlated significantly negatively with changes of IR index HOMA (r=-0.25), standard deviation score-body mass index (SDS-BMI) (r=-0.33) and leptin (r=-0.50). Substantial weight loss in 29 obese children led to a significant increase in osteocalcin and a significant decrease in leptin and HOMA. In 31 obese children without substantial weight loss, osteocalcin levels did not change significantly in the course of 1 year. CONCLUSION Osteocalcin levels were lower in obese children and were related to IR and leptin both in cross-sectional and longitudinal analyses. Therefore, osteocalcin might be a new promising link between obesity and IR.
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Affiliation(s)
- T Reinehr
- Department of Pediatric Nutrition Medicine, Vestische Hospital for Children and Adolescents Datteln, University of Witten/Herdecke, Germany.
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Riedt CS, Brolin RE, Sherrell RM, Field MP, Shapses SA. True fractional calcium absorption is decreased after Roux-en-Y gastric bypass surgery. Obesity (Silver Spring) 2006; 14:1940-8. [PMID: 17135609 PMCID: PMC4016232 DOI: 10.1038/oby.2006.226] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
OBJECTIVE Roux-en-Y gastric bypass (RYGB) is considered to be the gold standard alternative treatment for severe obesity. Weight loss after RYGB results primarily from decreased food intake. Inadequate calcium (Ca) intake and metabolic bone disease can occur after gastric bypass. To our knowledge, whether malabsorption of Ca contributes to an altered Ca metabolism in the RYGB patient has not been addressed previously. RESEARCH METHODS AND PROCEDURES We recruited 25 extremely obese women in order to study true fractional Ca absorption (TFCA) before and 6 months after RYGB surgery, using a dual stable isotope method ((42)Ca and (43)Ca) and test load of Ca (200 mg). Hormones regulating Ca absorption and markers of bone turnover were also measured. RESULTS In 21 women (BMI 52.7 +/- 8.3 kg/m(2), age 43.9 +/- 10.4 years) who successfully completed the study, TFCA decreased from 0.36 +/- 0.08 to 0.24 +/- 0.09 (p < 0.001) after RYGB. Bone turnover markers increased significantly (p < 0.01). TFCA correlated with estradiol levels (r = 0.512, p < 0.02) and tended to correlate with 1,25 (OH)(2)D (r = 0.427, p < 0.06) at final measurement. Stepwise linear regression indicated that estradiol explained 62% of the variance for TFCA at 6 months post-surgery (p < 0.01). DISCUSSION TFCA decreases (0.12 +/- 0.08) after RYGB surgery but remains within normal range. Although only some patients were estimated to have low Ca absorption after surgery, all of the patients showed a dramatic increase in markers of bone resorption. The alteration in Ca metabolism after RYGB-induced weight loss appears to be regulated primarily by estradiol levels and might ultimately affect bone mass.
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Affiliation(s)
- Claudia S. Riedt
- Department of Nutritional Sciences, Rutgers University, New Jersey
| | | | - Robert M. Sherrell
- Institute of Marine and Coastal Sciences, Rutgers University, New Jersey
| | - M. Paul Field
- Institute of Marine and Coastal Sciences, Rutgers University, New Jersey
| | - Sue A. Shapses
- Department of Nutritional Sciences, Rutgers University, New Jersey
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