Overweight postmenopausal women lose bone with moderate weight reduction and 1 g/day calcium intake

The decline in hip bone density after gastric bypass surgery is associated with extent of weight loss

CONTEXT

Bariatric surgery is common and may be associated with deleterious effects on the skeleton.

OBJECTIVE

Our objective was to assess bone metabolism and bone mineral density (BMD) after Roux-en-Y gastric bypass.

DESIGN AND SETTING

We conducted a 1-yr prospective longitudinal study at a university hospital bariatric surgery practice and metabolic bone disease unit.

PARTICIPANTS

Participants included 23 obese (mean body mass index 47 kg/m(2)) men and women, aged 20-64 yr.

MAIN OUTCOME MEASURES

Serum PTH, 25-hydroxyvitamin D, osteocalcin, and urinary N-telopeptide, and BMD were assessed.

RESULTS

Patients lost 45 +/- 2 kg 1 yr postoperatively (P < 0.01). PTH increased early (3 months, 43-50 pg/ml; P < 0.001) and urinary calcium dropped (161-92 mg/24 h; P < 0.01), despite doubling of calcium intake (1318-2488 mg/d; P < 0.001). Serum 25-hydroxyvitamin D concentrations were unchanged (23-26 ng/ml), although vitamin D intake increased by 260% (658 IU/d at baseline to 1698 IU/d at 12 months; P < 0.05). Markers of bone remodeling rose (P < 0.01 for both urinary N-telopeptide and osteocalcin), whereas BMD decreased at the femoral neck (9.2%, P < 0.005) and at the total hip (8.0%, P < 0.005). These declines were strongly associated with the extent of weight loss (femoral neck: r = 0.90, P < 0.0001; and total hip: r = 0.65, P = 0.02). Lumbar spine and distal radius sites did not change.

CONCLUSIONS

After Roux-en-Y gastric bypass, there was evidence of calcium and vitamin D malabsorption. Bone turnover increased, and hip bone density rapidly declined. The decline in hip BMD was strongly associated with weight loss itself. Vigilance for nutritional deficiencies and bone loss in patients both before and after bariatric surgery is crucial.

The presence of both an energy deficiency and estrogen deficiency exacerbate alterations of bone metabolism in exercising women

BACKGROUND

Bone loss in amenorrheic athletes has been attributed to energy deficiency-related suppression of bone formation, but not increased resorption despite hypoestrogenism.

OBJECTIVE

To assess the independent and combined effects of energy deficiency and estrogen deficiency on bone turnover markers in exercising women.

DESIGN

PINP, osteocalcin, U-CTX-I, TT3, leptin, and ghrelin were measured repeatedly, and bone mineral density (BMD) was measured once in 44 exercising women. Resting energy expenditure (REE) was used to determine energy status (deficient or replete) and was corroborated with measures of metabolic hormones. Daily levels of urinary estrone and pregnanediol glucuronides (E1G, PdG), were assessed to determine menstrual and estrogen status. Volunteers were then retrospectively categorized into 4 groups: 1) Energy Replete+Estrogen Replete (EnR+E2R), (n=22), 2) Energy Replete+Estrogen Deficient (EnR+E2D), (n=7), 3) Energy Deficient+Estrogen Replete (EnD+E2R), (n=7), and 4) Energy Deficient+Estrogen Deficient (EnD+E2D), (n=8).

RESULTS

The groups were similar (p>0.05) with respect to age (24.05+/-1.75 yrs), weight (57.7+/-2.2 kg), and BMI (21.05+/-0.7 kg/m2). By design, REE/FFM (p=0.028) and REE:pREE (p<0.001) were lower in the EnD vs. EnR group, and the E2D group had a lower REE:pREE (p=0.005) compared to the E2R group. The EnD+E2D group had suppressed PINP (p=0.034), and elevated U-CTX-I (p=0.052) and ghrelin (p=0.028) levels compared to the other groups. These same women also had convincing evidence of energy conservation, including TT3 levels that were 29% lower (p=0.057) and ghrelin levels that were 44% higher (p=0.028) than that observed in the other groups. Energy deficiency was associated with suppressed osteocalcin, and TT3 (p<0.05), whereas estrogen deficiency was associated with decreased E1G (p<0.02), and lower L2-L4 BMD (p=0.033). Leptin was significant in predicting markers of bone formation, but not markers of bone resorption.

CONCLUSIONS

When the energy status of exercising women was adequate (replete), there were no apparent perturbations of bone formation or resorption, regardless of estrogen status. Estrogen deficiency in exercising women, in the presence of an energy deficiency, was associated with bone loss and involved suppressed bone formation and increased bone resorption. These findings underscore the importance of avoiding energy deficiency, which is associated with hypoestrogenism, to avoid bone health problems.

Effect of weight loss and exercise therapy on bone metabolism and mass in obese older adults: a one-year randomized controlled trial

BACKGROUND

Although weight loss and exercise ameliorates frailty and improves cardiac risk factors in obese older adults, the long-term effect of lifestyle intervention on bone metabolism and mass is unknown.

OBJECTIVE

The objective was to evaluate the effects of diet-induced weight loss in conjunction with exercise on bone metabolism and mass in obese older adults.

DESIGN AND SETTING

We conducted a one-year randomized, controlled clinical trial in a university-based research center.

PARTICIPANTS

Twenty-seven frail, obese (body mass index = 39 +/- 5 kg/m(2)), older (age 70 +/- 5 yr) adults participated in the study.

INTERVENTION

Participants were randomly assigned to diet and exercise (treatment group; n = 17) or no therapy (control group; n = 10).

OUTCOME MEASURES

Body weight decreased in the treatment group but not in the control group (-10 +/- 2 vs. +1 +/- 1%, P < 0.001). Compared with the control group, the treatment group had greater changes in bone mass, bone markers, and hormones, including 1) bone mineral density (BMD) in total hip (0.1 +/- 2.1 vs. -2.4 +/- 2.5%), trochanter (0.2 +/- 3.3 vs. -3.3 +/- 3.1%), and intertrochanter (0.3 +/- 2.7 vs. -2.7 +/- .3.0%); 2) C-terminal telopeptide (12 +/- 35 vs. 101 +/- 79%) and osteocalcin (-5 +/- 15 vs. 66 +/- 61%); and 3) leptin (2 +/- 12 vs. -30 +/- 25%) and estradiol (0.1 +/- 14% vs. -14 +/- 21%) (all P < 0.05). Changes in weight (r = 0.55), bone markers (r = -0.54), and leptin (r = 0.61) correlated with changes in hip BMD (all P < 0.05).

CONCLUSION

Weight loss, even when combined with exercise, decreases hip BMD in obese older adults. It is not known whether the beneficial effects of weight loss and exercise on physical function lower the overall risk of falls and fractures, despite the decline in hip BMD.

Influence of moderate energy restriction and seafood consumption on bone turnover in overweight young adults

BACKGROUND

Overweight and obesity are increasing in young adults. However, moderate energy restriction aimed at lowering body weight may promote bone turnover and bone loss. Inclusion of fish or fish oils in a weight-loss diet may attenuate these adverse skeletal effects.

OBJECTIVE

We examined the effects of incorporating fish or fish oil into an energy-restricted diet on bone turnover markers in young overweight adults.

DESIGN

While following a strict hypoenergetic (-30% relative to estimated requirements) diet for 8 wk, 276 overweight men and women [body mass index (in kg/m(2)): 27.5-32.5; age: 20-40 y) were randomly assigned to 1 of 4 dietary groups: sunflower-oil capsules (3 g/d; control), cod (3 x 150 g/wk), salmon (3 x 150 g/wk), and fish-oil capsules (3 g/d). Body weight, bone biomarkers, and 25-hydroxyvitamin D were measured at baseline and endpoint. Data were analyzed with repeated-measures analysis of variance and general linear models.

RESULTS

The mean (+/-SD) weight loss was 5.14 +/- 3.0 kg (5.8% +/- 3.2% body weight) during the 8 wk in the 4 dietary groups combined. Urinary N-telopeptides of type I collagen and serum C-terminal telopeptide of type I collagen increased (P < 0.05), whereas serum osteocalcin (but not bone-specific alkaline phosphatase) decreased (P < 0.05) from baseline to endpoint. Increased fish or fish-oil consumption had no effect (P > 0.1) on the changes in bone markers induced by weight loss. In contrast, increased salmon consumption increased serum 25-hydroxyvitamin D (P < 0.01).

CONCLUSIONS

A nutritionally adequate but energy-restricted diet, with different contents of n-3 fatty acids, which resulted in modest weight loss, unfavorably altered bone turnover markers in young overweight adults. Such changes were not prevented by increased fish or fish-oil consumption.

Mineral metabolism in obese patients following vertical banded gastroplasty

BACKGROUND

Bone disease has been described in patients after surgical treatment for obesity, but few studies have dealt with the impact of vertical banded gastroplasty on mineral metabolism. We have examined bone mineral metabolism in morbidly obese patients before and after 3 months after vertical banded gastroplasty without vitamin D supplementation.

METHODS

Sixteen morbidly obese patients (14 women, 2 men) with a mean (+/-SD) age of 38 +/- 9 years and a body mass index (BMI) of 47.1 +/- 8.1 kg/m2 were studied. No vitamin D supplementation was given. Body weight, fat mass, calcium, 25OHD, iPTH, bone remodeling markers, and leptin levels were measured at baseline and after weight loss.

RESULTS

Mean weight loss was 28 +/- 11 kg; BMI and body fat mass decreased by 20 and 35%, respectively. Bone resorption markers and albumin-corrected serum calcium increased after operation, whereas iPTH fell. Serum 25OHD levels rose. Leptin levels decreased. Serum iPTH was positively correlated with weight, BMI, and fat mass before operation (p < 0.05), and its decline after weight reduction was negatively associated with the increase in bone resorption markers (p < 0.01). Leptin concentration was correlated with BMI and body fat mass (p < 0.05) both before and after surgery.

CONCLUSIONS

Weight reduction obtained in morbidly obese subjects 3 months after vertical banded gastroplasty increases bone turnover markers and decreases PTH secretion. Serum 25OHD levels rose. Therefore, no reasons for a metabolic bone disease related to hypovitaminosis D were readily apparent. However, an increase in bone turnover, which is generally regarded as a potential risk factor for osteoporosis, was observed. Further work is needed to clarify the importance of this turnover increase in the long run.

Effects of additional resistance training during diet-induced weight loss on bone mineral density in overweight premenopausal women

Bone loss accompanies a diet-induced weight loss and could be prevented with a combination of exercises. This study was conducted to examine the effects of additional resistance training during diet-induced weight loss on whole-body and selected regional bone mineral density (BMD). The participants of a 14-week weight-loss study were 42 overweight premenopausal Japanese women who were randomly placed in either a diet-only group (D; n = 21) or a diet plus resistance training group (DR; n = 21). Whole-body BMD and body composition, lumbar spine BMD, and 1/3 radial BMD were measured by dual-energy X-ray absorptiometry before and after the intervention. Bone formation and resorption markers were also measured. Thirty-five participants (83%) completed the study. Individuals in groups D (n = 17) and DR (n = 18) lost 6.2 +/- 3.5 kg and 8.6 +/- 3.6 kg body weight, respectively. Reductions in percentage fat mass and fat mass in group DR were significantly greater than in group D; lean mass decreased significantly in both groups. The effect of time on whole-body BMD was significant (-0.3%); however, whole-body bone mineral content, lumbar spine BMD, and 1/3 radial BMD remained unchanged. There were no significant timeby-group interactions in the whole-body and regional BMD and bone markers. These results suggest that additional resistance training during weight loss has no effect on BMD in overweight premenopausal Japanese women. Further long-term studies with large numbers of subjects are needed.

The impact of obesity on the musculoskeletal system

Obesity is associated with a range of disabling musculoskeletal conditions in adults. As the prevalence of obesity increases, the societal burden of these chronic musculoskeletal conditions, in terms of disability, health-related quality of life, and health-care costs, also increases. Research exploring the nature and strength of the associations between obesity and musculoskeletal conditions is accumulating, providing a better understanding of underlying mechanisms. Weight reduction is important in ameliorating some of the manifestations of musculoskeletal disease and improving function.

Intérêt d'une bonne hygiène dans la prévention de l’ostéoporose : le rôle du gynécologue

Post-menopausal osteoporosis is a public health problem, because of its extreme frequency and its related fractures. Gynaecologists play an important role in the early detection of patients whose bones are at risk. During the consultation, a routine examination, asking pertinent questions and taking height and weight measurements, allows for the discovery of modifiable risk factors - diet, life style: physical activity, alcohol and tobacco consumption, etc. Gynaecologists are in a particularly good position to intervene. Indeed, they can inform and advise these patients at risk, by recommending a diet rich in calcium, vitamin D and protein, maintaining a healthy BMI, a sufficient exposure to sunlight, daily physical activity with a preference for weight-bearing exercise, avoiding smoking and excessive alcohol. These simple changes for a healthy life style can slow down the loss of bone density, and this well before any loss due to estrogen deficiency.

Calcium and body fat in peripubertal girls: cross-sectional and longitudinal observations

OBJECTIVE

The objective was to investigate whether calcium intake is independently associated with body fat in peripubertal girls.

RESEARCH METHODS AND PROCEDURES

A total of 45 healthy premenarcheal girls (initially 10.5 +/- 0.6 years of age) completed a 2-year prospective observational study. Percent body fat and trunk fat (by DXA), height, weight, maturational stage, and eating attitudes (children's Eating Attitudes Test [EAT]) were measured at baseline and at 1 and 2 years. Physical activity (by questionnaire) and calcium intake (by calcium-specific food frequency questionnaire and 3-day food records) were assessed at 6-month intervals.

RESULTS

Girls with 2-year mean calcium intake below and above the median had similar age, height, lean mass, and maturational stage at baseline, but girls below the median had significantly higher baseline percentage body fat (29.3 +/- 10.3% vs. 22.0 +/- 6.8%, p < 0.01) and trunk fat (24.2 +/- 10.6% vs. 15.8 +/- 6.8%, p < 0.01). However, differences were no longer significant when covariates (most notably children's EAT dieting score) were considered. Regression analysis revealed that dieting score was a consistent positive predictor of percentage body and trunk fat at all cross-sectional time-points, accounting for >20% of the variance, but did not predict 2-year change in percentage fat. Calcium intake did not enter longitudinal regression equations for 2-year change in percentage fat.

DISCUSSION

In this group of girls, an inverse cross-sectional association between calcium intake and body fat appeared to result from avoidance of foods high in calcium by girls who were concerned about their body weight or shape. Calcium intake was not associated with change in fat over time.

Premenopausal overweight women do not lose bone during moderate weight loss with adequate or higher calcium intake

BACKGROUND

Weight loss is associated with bone loss, but this has not been examined in overweight premenopausal women.

OBJECTIVE

The aim of this study was to assess whether overweight premenopausal women lose bone with moderate weight loss at recommended or higher than recommended calcium intakes.

DESIGN

Overweight premenopausal women [n = 44; x (+/-SD) age: 38 +/- 6.4 y; body mass index (BMI): 27.7 +/- 2.1 kg/m(2)] were randomly assigned to either a normal (1 g/d) or high (1.8 g/d) calcium intake during 6 mo of energy restriction [weight loss (WL) groups] or were recruited for weight maintenance at 1 g Ca/d intake. Regional bone mineral density and content were measured by dual-energy X-ray absorptiometry, and markers of bone turnover were measured before and after weight loss. True fractional calcium absorption (TFCA) was measured at baseline and during caloric restriction by using a dual-stable calcium isotope method.

RESULTS

The WL groups lost 7.2 +/- 3.3% of initial body weight. No significant decrease in BMD or rise in bone turnover was observed with weight loss at normal or high calcium intake. The group that consumed high calcium showed a strong relation (r = 0.71) between increased femoral neck bone mineral density and increased serum 25-hydroxyvitamin D. No significant effect of weight loss on TFCA was observed, and the total calcium absorbed was adequate at 238 +/- 81 and 310 +/- 91 mg/d for the normal- and high-calcium WL groups, respectively.

CONCLUSION

Overweight premenopausal women do not lose bone during weight loss at the recommended calcium intake, which may be explained by sufficient amounts of absorbed calcium.

Weight-bearing, aerobic exercise increases markers of bone formation during short-term weight loss in overweight and obese men and women

We investigated the impact of weight-bearing, aerobic exercise- and diet-induced weight loss on markers of bone turnover during a larger study of changes in metabolic fitness during short-term weight reduction using a repeated-measures, within-subject experimental design. Subjects (N = 19) underwent 6 weeks of energy restriction (reduced by approximately 3140 kJ/d) and aerobic exercise ( approximately 1675 kJ/d, walking or jogging at 60% maximum oxygen consumption) to induce a 5% reduction in body weight. Bone turnover markers and hormones were measured in serum collected at baseline and after 6 weeks of weight loss. Despite a 5% reduction in body weight at week 6, markers of bone formation, osteocalcin, and bone alkaline phosphatase, were significantly increased, and resorption markers, C-terminal cross-links of type I collagen and soluble receptor activator of nuclear factor kappaB ligand, were unchanged after 6 weeks of energy restriction and exercise. The concentration of leptin was significantly reduced after weight loss, but insulin-like growth factor I (IGF-I) and cortisol levels were unaffected. In conclusion, weight-bearing, aerobic exercise training may favorably affect the balance between bone resorption and formation during weight loss.

True fractional calcium absorption is decreased after Roux-en-Y gastric bypass surgery

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.

Bone, body weight, and weight reduction: what are the concerns?

Of the U.S. population, 65% is either overweight or obese, and weight loss is recommended to reduce co-morbid conditions. However, bone mobilization and loss may also occur with weight loss. The risk for bone loss depends on initial body weight, age, gender, physical activity, and conditions of dieting such as the extent of energy restriction and specific levels of nutrient intake. Older populations are more prone to bone loss with weight loss; in women, this is due at least in part to a reduced dietary Ca intake and/or efficiency of absorption. Potential hormonal mechanisms regulating bone loss during weight loss are discussed, including decreases in estrogen, leptin, glucagon-like peptide-2, growth hormone, and insulin-like growth factor-1, or an increase in cortisol. In contrast, the rise in adiponectin and ghrelin with weight reduction should not be detrimental to bone. Combining energy restriction with exercise does not necessarily prevent bone loss, but may attenuate loss as was shown with additional Ca intake or osteoporosis medications. Future controlled weight loss trials should be designed to further address mechanisms influencing the density and quality of bone sites vulnerable to fracture, in the prevention of osteoporosis.