Differences in Bone Turnover and Skeletal Response to Thyroid Hormone Treatment Between Estrogen-Depleted and Repleted Rats

This study was undertaken to compare the effect of supraphysiological doses of thyroxine (T4) on bone metabolism in SHAM and OVX young adult rats. Female Sprague Dawley rats (220 ± 2 g, approx. 5 months of age) were divided into four groups of eight animals each. The animals were intraperitoneally injected 6 days per week with vehicle (Vh): 0.001 N NaOH/0.9% NaCl (SHAM+Vh and OVX+Vh) or 250 μg of thyroxine/kg/day (SHAM+T4 and OVX+T4) during a 5-week period. Serum T4 and osteocalcin (BGP), urinary pyridinolines (Pyr), and creatinine (creat) were determined. At the beginning and at end of the experiment, skeletal bone mineral content (BMC), bone mineral density (BMD), and area (A) of the total skeleton, femur, spine, and whole tibia, as well as proximal, middle, and distal areas of the tibia were assessed by dual X-ray absorptiometry (DXA) in an ultra-high-resolution mode. T4 treatment of the SHAM rats did not induce significant changes in BGP level or Pyr/creat excretion compared with the SHAM+Vh control group. However, these two biochemical bone markers significantly increased due to T4 treatment in OVX rats compared with both OVX+Vh and SHAM+T4 groups (P < 0.05 and P < 0.001, respectively). The OVX+T4 group had a significantly lower ΔBMD than SHAM+T4 rats in all studied regions (P < 0.05) except for the middle tibia region. OVX+T4 groups presented a significantly lower ΔBMC and ΔA compared with SHAM+T4 animals (P < 0.001). OVX+T4 rats significantly impaired the ΔBMD in the femur (P < 0.01), spine (P < 0.05), whole (P < 0.05) and middle (P < 0.05) tibia whereas T4 treatment of SHAM rats only affected, significantly, the whole (P < 0.05) and the proximal tibia region (P < 0.01). T4 treatment affects bone growth in young adult rats. The effect is significantly greater in the estrogen-depleted than in the estrogen-repleted state. The bone site most adversely affected by T4 treatment depends on the estrogen status. The proximal tibia (principally trabecular bone) was the most affected area in estrogen-repleted rats. Conversely, in OVX rats, the middle tibia (principally cortical bone) presented the greatest decrease in bone density. Received: 20 May 1999 / Accepted: 4 February 2000     

The Phytoestrogen Genistein Reduces Bone Loss in Short-Term Ovariectomized Rats

The incidence of fractures and of osteoporosis differs between Oriental and Western Caucasian women. This may depend, at least in part, on nutritional factors, including dissimilarities in dietary intake of phytoestrogens. To investigate this possibility, 2-month-old female rats were ovariectomized (OVX) or sham-operated (SHAM), fed a casein-based diet, injected daily with subcutaneous genistein (GEN), the most abundant and best characterized phytoestrogen, or vehicle (Veh) and killed 21 days after surgery. As expected, ovariectomy resulted in loss of bone mineral density (BMD) and in uterine atrophy. However, administration of 5 mg GEN per gram body weight (b.w.) ameliorated the ovariectomy-induced loss of BMD (189 ± 2 mg/cm² in OVX and 192 ± 2 in OVX with 5 mg GEN/g b.w. per day; p<0.05). One microgram GEN per gram body weight did not affect the BMD loss and the effect of the 5 mg and 25 mg GEN per gram body weight were statistically not different. A trend toward reduced uterine atrophy (21% reduction) was noted with the 25 mg GEN dose, but not with the 1 mg and 5 mg doses. A separate experiment with 2 x 2 factorial design was conducted to elucidate the mechanism by which GEN ameliorates ovariectomy-induced bone loss. In this experiment, histomorphometry demonstrated a dramatic reduction in trabecular bone volume after ovariectomy (7.6 ± 0.7% of total bone volume in SHAM-Veh vs 3.3 ± 0.2% in OVX-Veh; p<0.01) and less bone loss in OVX rats injected with 5 mg GEN per gram per day (3.3 ± 0.2% of total bone volume in OVX-Veh vs 5.2 ± 0.4% in OVX-GEN; p<0.01). Administration of GEN was associated with higher bone formation rate per tissue volume and with a trend toward a higher number of osteoblasts per bone perimeter. The parameters of bone resorption were not affected by GEN. The concentration of serum osteocalcin and the urinary excretion of deoxypyridinoline provided corroborating results. Since production of proinflammatory cytokines is intimately involved in the pathogenesis of postmenopausal osteoporosis, the effect of GEN on lipopolysaccharide-induced in vitro production of Tumor necrosis factor-alpha (TNFa) was tested in monocytic cells from the same four rat groups. Production of TNFa was markedly elevated in OVX-Veh as compared with the SHAM-Veh rats, but this was blocked by GEN in the OVX rats. This study shows that GEN reduces both trabecular and compact bone loss after ovariectomy and that this protective effect differs from that of estrogen, since it depends on stimulation of bone formation rather than on suppression of bone resorption. Lack of action of GEN on uterine atrophy supports the possibility that this GEN dose affects target tissues via non-estrogenic mechanisms. Modulation of cytokine production may be involved in the effect of GEN on bone. Received: 27 June 1997 / Accepted: 27 October 1997     

Recovery of proximal tibia bone mineral density and strength, but not cancellous bone architecture, after long-term bisphosphonate or selective estrogen receptor modulator therapy in aged rats.

Various bisphosphonates and the selective estrogen receptor modulator (SERM) raloxifene are approved treatments of postmenopausal osteoporosis. They increase bone mineral density (BMD), decrease bone turnover, and reduce vertebral fracture incidence through different cellular mechanisms. We investigated the bone cellular activities, architecture, mineral content/density, and strength of ovariectomized (ovx) rats on a long-term bisphosphonate or SERM treatment, at doses of either agent correcting bone strength. Eleven weeks postovariectomy, 6-month-old rats were treated with the SERM MDL 103,323 or with the bisphosphonate pamidronate for 5 months. Doses of pamidronate and MDL 103,323 were selected from previous studies showing correction of the ovx-induced decrease of ultimate strength of proximal tibia. Ultimate and yield strengths, BMD, and histomorphometric parameters were all quantified at the same site, i.e., the proximal tibia metaphysis. Long-term pamidronate decreases bone turnover and bone formation activity, leading to trabecular thinning. MDL 103,323 decreases bone turnover to a lesser extent, and slightly protects trabecular architecture by uncoupling bone resorption and formation activities. The yield strength is corrected by pamidronate, but not by MDL 103,323 treatment. However, neither compound restores the ovariectomy-induced cancellous bone loss. Total tissue area and cortical thickness are unchanged with pamidronate or MDL 103,323 treatment, indicating that cortical bone mass, thickness, and cross-sectional area are not modified. The discrepancy between proximal tibia BMD and mechanical resistance to fracture modifications, on the one hand, and cancellous bone volume, on the other hand, could be due to changes in the degree of mineralization of bone matrix and/or of the intrinsic properties of the bone matrix.     

Treatment of Postmenopausal Women with Osteoporosis or Low Bone Density with Raloxifene

Raloxifene, a selective estrogen receptor modulator (SERM), has been shown to improved bone mineral density (BMD) and serum lipid profiles in healthy postmenopausal women. The objective of this study was to examine the effects of raloxifene on BMD, biochemical markers of bone metabolism and serum lipids in postmenopausal women with low bone density or osteoporosis. This Phase II, multicenter, 24-month, double-masked study assessed the efficacy and safety of raloxifene in 129 postmenopausal women (mean age ± SD: 60.2 ± 6.7 years) with osteoporosis or low bone density (baseline mean lumbar spine BMD T-score: −2.8). Women were randomly assigned to one of three treatment groups: placebo, 60 mg/day raloxifene-HCl (RLX 60) or 150 mg/day raloxifene-HCl (RLX 150) and concomitantly received 1000 mg/day calcium and 300 U/day vitamin D₃. At 24 months, BMD was significantly increased in the lumbar spine (+3.2%), femoral neck (+2.1%), trochanter (+2.7%) and total hip (+1.6%) in the RLX 60 group compared with the placebo group (p<0.05). The RLX 150 group had increases in BMD similar to those observed with RLX 60. A greater percentage of raloxifene-treated patients, compared with those receiving placebo, had increased BMD (p<0.05). Serum bone-specific alkaline phosphatase activity, serum osteocalcin, and urinary type I collagen:creatinine ratio were significantly decreased in the RLX-treated groups, compared with the placebo group (p<0.01). RLX 60 treatment significantly decreased serum levels of triglycerides, and total- and LDL-cholesterol levels (p<0.01). The rates of patient discontinuation and adverse events were not significantly different among groups. In this study, raloxifene increased bone density, decreased bone turnover, and improved the serum lipid profile with minimal adverse events, and may be a safe and effective treatment for postmenopausal women with osteoporosis or low bone density. Received: 26 December 1998 / Accepted: 31 March 1999     

Abnormal Bone Turnover in Cystic Fibrosis Adults

Cystic fibrosis (CF) patients often have low bone mineral density (BMD) and may suffer from fractures and kyphosis. The pathogenesis of low BMD in CF is multifactorial. To study bone metabolism, we collected fasting serum and urine from 50 clinically stable CF adults (mean age 28 years) and 53 matched controls to measure markers of bone formation and bone resorption. The CF subjects had moderate lung disease (FEV₁: 46.1 ± 18.6% predicted) and malnutrition (BMI: 20.0 ± 3.3 kg/m²). Only 3 subjects had normal BMD. CF subjects had higher urinary N-telopeptides of type I collagen (81.0 ± 60.0 vs 49.0 ± 24.2 nm BCE/mmol creatinine, p= 0.0006) and free deoxypyridinoline (7.3 ± 5.0 vs 5.3 ± 1.9 nM/mM, p= 0.004) levels than controls. Serum osteocalcin levels were similar in the two groups, a result confirmed by two immunoassays that recognize different epitopes on osteocalcin. Serum bone-specific alkaline phosphatase levels were elevated in CF patients (32.0 ± 11.3 vs 21.8 ± 7.0 U/l, p<0.0001), but were much more closely associated with serum total alkaline phosphatase levels (r = 0.51, p = 0.001) than with age or gender. Parathyroid hormone levels were elevated (p= 0.007) and 25-hydroxyvitamin D levels were depressed (p= 0.0002) in the CF patients in comparison with controls. These results indicate that adults with CF have increased bone resorption with little change in bone formation. Medications that decrease bone resorption or improve calcium homeostasis may be effective therapies for CF bone disease. Received: 22 June 2001 / Accepted: 1 August 2001     

High Bone Mineral Density in Male Elite Professional Volleyball Players

The aim of this study was to assess bone mass in male elite athletes participating in an impact loading sport (volleyball) and, in particular, to determine whether the asymmetric nature of this sport leads to differences in the skeletal tissue composition of the limbs. Fifteen male volleyball players (VP) (26 ± 4 years, 192 ± 6 cm, 87 ± 9 kg; mean ± SD) and 15 non-active control subjects (25 ± 2 years, 177 ± 8 cm, 72 ± 11 kg; mean ± SD) were studied. VP training sessions (3–6 days/week) included a variety of jumping and weightlifting exercises. The VP were taller and heavier than the control subjects (p<0.001). Whole-body bone mineral content (BMC) and lean mass were higher in VP after adjustment for body mass and height (p<0.001). Axial skeleton and limb BMC and bone mineral density (BMD) were higher in VP than in control subjects (p<0.05). Adjusted lumbar spine (L2–4) BMD was 14% higher in VP than in control subjects (p<0.05). Similarly, a much greater adjusted BMD was observed in the femoral neck of VP (24%, 20%, 27% and 20% for the femoral neck, intertrochanteric, greater trochanter and Ward’s triangle subregions respectively; p<0.05). The dominant arm was slightly heavier (≈3%) and had 4% more muscle mass than the contralateral arm in both the VP (p<0.05) and control subjects (p<0.05). Greater BMC values (9%), BMD (7%) values and the area occupied by osseous pixels (5%) were recorded in the dominant arm as compared with the nondominant arm in VP (p<0.05). No differences between arms were observed in control subjects. Right and left leg BMC and BMD values were similar in control subjects while 4% higher BMC values were recorded for the left leg in the VP group (p<0.05). A close relationship between left leg muscle mass and BMD was observed in the femoral neck subregions of all the subjects (r= 0.81, 0.81, 0.78 and 0.79 for the femoral neck, intertrochanteric, greater trochanter and Ward’s triangle subregions respectively; p<0.001; n= 30). These findings clearly demonstrate a considerably high BMC and BMD in professional volleyball players which seems to be related to the loading type of exercise they perform. Received: 26 October 1998 / Accepted: 26 May 1999     

Bone Mineral Density and Metabolism in Familial Dysautonomia

Familial dysautonomia (FD) patients suffer from multiple fractures and have reduced bone pain, which defers the diagnosis. The pathogenesis of bone fragility in FD is unknown. This study aimed to characterize bone mineral metabolism and density in FD. Seventy-nine FD patients aged 8 months to 48 years (mean age 13.9 ± 10.4 years, median 12.3) were studied. Clinical data included weight, height, bone age, weekly physical activity and history of fractures. Bone mineral density (BMD) of the lumbar spine (n= 43), femoral neck (n= 26), total hip (n= 22) and whole body (n= 15) were determined by dual-energy X-ray absorptiometry. Serum 25-hydroxyvitamin D₃, osteocalcin, bone alkaline phosphatase (B-ALP), parathyroid hormone and urinary N-telopeptide cross-linked type 1 collagen (NTx) were determined in 68 patients and age- and sex-matched controls. Forty-two of 79 patients (53%) sustained 75 fractures. Twenty-four of 43 patients had a spine Z-score <–2.0, and 13 of 26 had a femoral neck Z-score <–2.0. Mean femoral neck BMD Z-score was lower in patients with fractures compared with those without (–2.5 ± 0.9 vs –1.5 ± 1.0, p= 0.01). Mean body mass index (BMI) was 16 kg/m² in prepubertal patients and 18.4 kg/m² in postpubertal patients. Bone age was significantly lower than chronological age (75.5 vs 99.3 months in prepubertal patients, p<0.001; 151 vs 174 in post-pubertal patients, p<0.05). NTx and osteocalcin levels were higher in FD patients compared with controls (400 ± 338 vs 303 ± 308, BCE/mM creatinine p<0.02; 90 ± 59.5 vs 61.8 ± 36.9 ng/ml, p<0.001, respectively). B-ALP was lower in FD patients compared with controls (44.66 ± 21.8 vs 55.36 ± 36.6 ng/ml, p<0.04). Mean spine Z-score was significantly lower in physically inactive compared with active patients (–3.00 ± 1.70 vs –1.77 ± 1.3, respectively, p= 0.05). We conclude that fractures in FD patients are associated with reduced BMD. FD patients have increased NTx and osteocalcin. Contributing factors include reduced BMI, failure to thrive and reduced physical activity. Preventive therapy and early diagnosis are essential. Received: 21 May 2001 / Accepted: 27 November 2001     

Site-Specific Bone Measurements in Patients with Ankle Fracture

Ankle fracture is one of the most common fractures in adults, particularly postmenopausal women. Few studies have examined the bone mineral density (BMD) and ultrasound properties of bone close to the site of fracture in patients with ankle fracture. The aim of this study was to evaluate these measurements in women with ankle fractures compared with controls. We studied 31 healthy post-menopausal women ages 50–79 years (mean age 63.2 ± 3.3 years) from a population-based group and 31 postmenopausal women ages 52–76 years (mean age 61.2 ± 2.2 years) with an ankle fracture. Distal tibia and fibula BMD were measured by dual-energy X-ray absorptiometry using the Hologic QDR 1000/W densitometer. In addition to total distal and tibia BMD, three subregions were automatically selected: ultradistal, middle and one-quarter regions. Speed of sound (SOS) and broadband ultrasound attenuation (BUA) of the calcaneus were measured using the Lunar Achilles+ (LA+) and CUBA Clinical (CC). In addition to SOS and BUA, LA+ Stiffness Index (SI) was also measured. The nondominant limb was measured in the population group and the contralateral limb in the ankle group. Differences between the groups were determined using t-tests. The ankle fracture group was heavier than the control group by an average of 10 kg. BMD measurements were therefore adjusted for weight. There were no significant differences between the ankle fracture and control groups in lumbar spine BMD, total or regional ankle BMD or calcaneal BUA. However, calcaneal SOS was decreased in the ankle fracture group when measured on the LA+ and CC by 50 m/s (–2.0 SD units, p<0.001) and 19 m/s (–0.5 SD units, p<0.01) respectively. LA+ SI was decreased in the ankle fracture group by 14 units (–1.1 SD units, p<0.001). In conclusion, ankle fracture is not a typical osteoporotic fracture. However, there may be structural changes in the bone (unrelated to bone density) which result in increased fragility and susceptibility to fracture. Received: 7 May 2001 / Accepted: 29 August 2001     

Bone Loss Following Tibial Osteotomy: A Model for Evaluating Post-traumatic Osteopenia

The reduced bone mineral density (BMD) found in patients with fractures may, in part, follow rather than precede the fracture. We studied the magnitude and reversibility of bone loss in the 15 months following osteotomy in 21 men and 5 women with localized medial arthritis of the knee. BMD (mean ± SD), measured using dual-energy X-ray absorptiometry, decreased by a maximum of 35 ± 21% in the mid-diaphysis of the affected tibia at 9 months after surgery (p<0.001). At 15 months, reversal of bone loss in nonfractured bones was incomplete; the remaining deficit was 20 ± 27% relative to baseline (p<0.001). Maximum bone loss occurred at 9 months at the total body (5 ± 2%), spine (15 ± 17%) and at Ward’s triangle of the proximal femur of the unoperated limb (10 ± 17%) (all p<0.01). In summary, post-traumatic bone loss is region-specific with incomplete reversibility, at least after about 15 months. Deficits in BMD in cross-sectional studies of patients with fractures, held to be responsible for the bone fragility, may, in part, follow rather than precede the fracture. Received: 17 May 1999 / Accepted: 24 September 1999     

Effects of Promethazine on Bone Mass and on Bone Remodeling in Ovariectomized Rats: A Morphometric, Densitometric, and Histomorphometric Experimental Study

The effect of promethazine on bone is debated. We studied the effect of promethazine on bone and the mechanism of action involved by densitometric and histomorphometric measurements in female Wistar rats (100 days old, mean weight 25 ± 20 g). A control group of 15 rats was not manipulated. An experimental group of 15 rats were ovariectomized (OVX) at 100 days of life and fed a diet supplemented with 4.8 mg/kg promethazine hydrochloride (OVX + Prom). The group that underwent OVX and a group of 15 rats that underwent sham ovariectomy (Sham-OVX) were not treated with promethazine. After 30 days, all the rats were killed. Their femur and 5th lumbar vertebra were dissected and cleaned of soft tissue. Femoral length and vertebral height were measured with a caliper and bones were weighed on a precision balance. The bone mineral content (BMC) and bone mineral density (BMD) of the whole right femurs and 5th lumbar vertebras were measured by dual-energy X-ray absorptiometry (DXA). Trabecular bone volume (Cn-BV-TV%), trabecular number (Tb-N mm⁻¹), trabecular thickness (Tb-Th μm), and trabecular separation (Tb-Sp μm) were measured in the femurs by histomorphometric study of nondecalcified bone. Our results showed that promethazine significantly inhibited postovariectomy loss of bone mass (P < 0.0001) by significantly reducing bone resorption, as shown by the smaller trabecular spaces observed in the treated OVX rats (P < 0.0001). Received: 1 June 1998 / Accepted: 17 February 1999     

Allogeneic Bone Marrow Transplantation is Associated with a Preferential Femoral Neck Bone Loss

Osteoporosis is a major complication of organ transplantation. Little is known about the risk of developing osteoporosis in bone marrow transplant (BMT) recipients. We studied early and late changes in bone mineral density (BMD), as well as biochemical markers of bone remodeling, in patients at the time of allogeneic BMT (alloBMT) and up to 13 years thereafter. In a cross-sectional study, 102 patients (40 women, 62 men, mean age ± SEM, 38.9 ± 1.6 years) were segregated into a first group (A, n= 48) and evaluated before or during the first weeks (mean ± SD 0.3 ± 0.1 month, range –0.5 to 3 months) following alloBMT, and a second group (B, n= 54) studied 60.1 ± 5.6 months (range 6–156 months) following alloBMT. Lumbar spine (LS) BMD was similar in groups A and B and was within normal limits. In contrast, femoral neck (FN) Z- and T-scores were significantly decreased in group B compared with group A (–0.68 ± 0.14 vs –0.03 ± 0.14 SD and –0.84 ± 0.14 vs –0.22 ± 0.14 SD, respectively; p≤0.002). Osteopenia (T-score between –1 and –2.5 SD) was present in 35% of group A and 43% of group B patients (NS). Osteoporosis (T-score <–2.5 SD) was detected in 7% of group B patients, but in none of those in group A (p= 0.05). In a longitudinal study, 56 subjects were evaluated at the time of alloBMT, and 33 and 23 were studied 6 or 12 months later, respectively (13 women, 20 men, 37.5 ± 1.6 years). All were treated with supplements of calcium and vitamin D. Amenorrheic women received hormone replacement therapy (HRT). Three-monthly pamidronate infusions were given to 15 men and 10 non-amenorrheic women who were osteopenic/osteoporotic or had elevated baseline bone turnover markers. Mean baseline LS and FN Z- and T-scores were within normal range. Six months after BMT, FN BMD decreased by 4.2 ± 0.7% (p<0.001), and whole body BMD and bone mineral content by 1.5 ± 0.4% and 3.1 ± 0.6%, respectively (p≤0.0001). Twelve months after the graft, there was no further significant bone loss and only FN BMD decrease remained significantly different compared with baseline (–5.6 ± 1.1%, p≤0.0001). These results indicate that the risk of decreased BMD is higher for the femoral neck than the lumbar spine and whole body levels in patients with allogeneic bone marrow transplantation, and that bone loss occurs mainly during the first 6 months after the graft. Received: 9 February 2001 / Accepted: 23 May 2001     

Bone Metabolism and Gonad Function in Male Patients Undergoing Liver Transplantation: A Two-Year Longitudinal Study

Osteodystrophy is a major complication of end-stage liver disease, especially in postmenopausal women. Our aim in this study was to evaluate bone metabolism and gonad function in men undergoing orthotopic liver transplantation (OLTx). Twenty-three consecutive men (mean age 48 ± 13 years) evaluated for OLTx were studied, assessing the following parameters at baseline and 3, 6, 12 and 24 months after OLTx: lumbar spine (L2–L4) bone mineral density (BMD), parathyroid hormone (PTH), osteocalcin (BGP), 25-hydroxyvitamin D (25OHD), free testosterone (FT) and gonadotropins (FSH, LH). At baseline, 12 patients (52%) had a T-score <–2.5 SD and the mean BMD was 0.806 ± 0.11 g/cm² (range 0.470–1.045 g/cm²). The BMD was lower 3 months after OLTx and significantly higher 12 and 24 months after OLTx. A significant increase in serum BGP was observed at 6, 12 (p<0.05) and 24 months (p<0.005) after OLTx. The mean serum PTH level was 26.6 ± 3.1 pg/ml at baseline and increased significantly at 12 and 24 months (to 49.4 ± 9.9 and 61.2 ± 10.1 pg/ml, respectively; p<0.05). 25OHD serum levels were low at baseline and returned to the normal range after 12 and 24 months (baseline, 8.73 ± 1.54 ng/ml; 12 months, 16.4 ± 2.6 ng/ml; 24 months, 17.67 ± 3.1 ng/ml; p<0.05). FT was significantly lower at baseline than in a group of 10 healthy controls (5.09 ± 10.99, vs 10.3 ± 1.1 pg/ml; p<0.0001). After OLTx a significant increase in FT was recorded at 6, 12 (p<0.05) and 24 months (p<0.005). FT was not correlated with BMD, however. After OLTx an increase in FSH and LH was observed (but failed to reach statistical significance) at 3 and 6 months, followed by a slight reduction at 12 and 24 months. Thus a high proportion of men with end-stage liver disease do have osteoporosis. After OLTx, an early recovery of gonad function is observed, followed by an increase in bone mass, which occurs from the sixth month onward. Received: 3 October 2000 / Accepted: 21 March 2001     

Pregnancy and Lactation Confer Reversible Bone Loss in Humans

The influence of pregnancy on bone mineral density (BMD) was evaluated by dual-energy X-ray absorptiometry (DXA) in 73 women (mean age 29 years, range 20–44 years) postpartum. Fifty-five age-matched women served as controls. The influence of lactation was evaluated in 65 of the delivered women who were followed with repeated measurements, a mean of 4.5 ± 0.1 and 11.5 ± 0.1 months after the delivery. The influence of multiple pregnancies was evaluated in 39 premenopausal women (mean age 38 years, range 31–54 years) with a minimum of four pregnancies (range 4–7). Fifty-eight age-matched healthy premenopausal women with a maximum of two pregnancies (range 0–2) served as controls. Data are presented as mean ± SEM. BMD data are adjusted for differences in total fat mass and total lean mass. Lumbar spine BMD was 7.6 ± 0.1% and total body BMD 3.9 ± 0.1% lower in women postpartum compared with controls (both p<0.001). BMD did not decrease significantly in non-breastfeeding mothers. Mothers breastfeeding for 1–6 months decreased femoral neck BMD by 2.0 ± 1.0% during the first 5 months postpartum (p<0.001). No further BMD loss was seen between 5 and 12 months postpartum. Femoral neck BMD 12 months after delivery was 1.3 ± 0.8% lower than after delivery in mothers breastfeeding for 1–6 months (p= 0.05). Mothers breastfeeding for more than 6 months decreased Ward’s triangle BMD by 8.5 ± 1.0% and lumbar spine BMD by 4.1 ± 0.8% during the first 5 months postpartum (both p<0.05). No further BMD loss was seen between 5 and 12 months postpartum. Femoral neck BMD 12 months after delivery was 4.0 ± 1.1% lower and Ward’s triangle BMD 5.3 ± 1.9% lower than after delivery in mothers breastfeeding for more than 6 months (both p<0.05). BMD loss was higher during the first 5 months following delivery in the lactating women compared with the non-lactating women (p< 0.05 comparing lumbar spine BMD loss in lactating mothers versus non-lactating mothers). However, in women with a minimum of four pregnancies the BMD was no lower than in age-matched women with fewer pregnancies. Total duration of lactation was not correlated with the present BMD. In summary, pregnancy seem to confer a low BMD with additional BMD loss during 5 months of lactation. Even if complete restoration in BMD was not reached within 5 months of weaning, women with four pregnancies or more had a BMD no lower than women with two pregnancies or fewer. We conclude that neither an extended lactation period nor multiple pregnancies could be used as a risk factor when predicting women at risk for future osteoporosis. Received: 15 November 2000 / Accepted: 21 March 2001     

Measurement of Bone Mineral Density in Mother–Daughter Pairs for Evaluating the Family Influence on Bone Mass Acquisition: A GRIO Survey

The relative influence of genetic and environmental determinants on bone mass is still unclear. Using an original multicentric mode of recruitment, based on absorptiometry current practice, the hypothesis of a familial predisposition to low bone mineral content was assessed. The study was based on dual-energy X-ray absorptiometry (DXA) measurements of lumbar and femoral neck bone mineral density (BMD), using daughters of women with a low BMD (case mothers). These BMD values were compared with those of control daughters of women with a normal BMD. Case mothers (n= 72) aged 54.3 ± 4.8 years were recruited on the basis of a questionnaire and a vertebral Z-score < – 2 SD. Their healthy daughters of more than 20 years (n= 77) aged 28.2 ± 4.9 years had their vertebral and femoral BMD Z-score determined. The control groups were composed of mothers aged 54.1 ± 4.7 years, paired by age ± 2 years to the case mothers, and of their daughters of more than 20 years old, aged 27.7 ± 5.8 years. For daughters, a significant difference was found between the mean vertebral Z-scores (–0.82 ± 1.08 for cases and 0.01 ± 1.14 for controls, p < 0.0001). The difference was in the same direction but was not statistically significant for mean femoral Z-scores (–0.58 ± 1.15 for cases and –0.22 ± 1.33 for controls, p <0.073). These findings confirm the hypothesis of a familial predisposition to low BMD. Received: 18 June 1997 / Accepted: 16 January 1998     

Use of Phalangeal Bone Mineral Density and Multi-site Speed of Sound Conduction to Monitor Therapy with Alendronate in Postmenopausal Women

In women with postmenopausal osteoporosis (PMO), response to therapy with bisphosphonates is conventionally monitored using central-site (hip and spine) bone mineral density (BMD), but more convenient alternatives are desirable. During a randomized parallel-group study of the efficacy of once-weekly (80 mg vs 160 mg) oral alendronate in the treatment of PMO, 81 women (mean age 70.2 years ± 4.6 SD) had BMD measurements of total hip (TH) and lumbar spine (LS) (L1–L4, Hologic); and of the middle phalanx of the middle digit of the non-dominant hand (accuDXA) at baseline and after 6 and 12 months of therapy with alendronate. At the same timepoints, subjects also had measurements of speed of sound (SOS) through bone at four sites (distal 1/3 radius, proximal phalanx of the third finger, midshaft of the tibia and fifth metatarsal) using the Sunlight Omnisense Ultrasound Bone Sonometer. Data from both patient groups were pooled for this analysis. Mean TH BMD at baseline was 0.705 g/cm²± 0.093 (SD) and increased by 1.7%± 2.3% and 2.5%± 2.3% at 6 and 12 months respectively (p= 0.09 and p<0.0001). Mean LS BMD at baseline was 0.718 ± 0.076 g/cm² and increased by 3.9%± 3.6% and 6.1%± 3.5 % at 6 and 12 months respectively (both p<0.0001). There was no statistically significant change from baseline in mean BMD by accuDXA at either 6 or 12 months. The only statistically significant changes in SOS were at the radius (decrease in SOS at 12 months, p = 0.04) and tibia (increase at 6 months, p<0.01, but no change between baseline and 12 months). Baseline correlation coefficients between accuDXA and LS and TH DXA were 0.22 (p= 0.05) and 0.27 (p= 0.02) respectively. Correlation coefficients between SOS and LS DXA ranged from 0.05 to 0.22; and between SOS and TH DXA ranged from –0.08 to 0.10 (all p= NS). These data suggest that the response to alendronate therapy over this time period cannot be measured by accuDXA or Sunlight SOS at the sites studied. Received: 26 June 2001 / Accepted: 27 September 2001     

Geographic Differences in Bone Mineral Density of Mexican Women

The aim of this study was to generate standard curves for normal spinal and femoral neck bone mineral density (BMD) in Mexican women using dual-energy X-ray absorptiometry (DXA), to analyze geographic differences and to compare these with “Hispanic” reference data to determine its applicability. This was a cross-sectional study of 4460 urban, clinically normal, Mexican women, aged 20–90 years, from 10 different cities in Mexico (5 in the north, 4 in the center and 1 in the southeast) with densitometry centers. Women with suspected medical conditions or who had used drugs affecting bone metabolism, were excluded. Lumbar spine BMD was significantly higher (1.089 ± 0.18 g/cm²) in women from the northern part of Mexico, with intermediate values in the center (1.065 ± 0.17 g/cm²) and lower values (1.013 ± 0.19 g/cm²) in the southeast (p<0.0001). Similarly, femoral neck BMD was significantly higher in women from the north (0.895 ± 0.14 g/cm²), intermediate in the center (0.864 ± 0.14 g/cm²) and lower (0.844 ± 0.14 g/cm²) in the southeast part of Mexico (p<0.0001). Northern Mexican women tend to be taller and heavier than women from the center and, even more, than those from the southeast of Mexico (p<0.0001). However, these differences in BMD remained significant after adjustment for weight (p<0.0001). A significant loss (p<0.0001) in BMD was observed from 40 to 69 years of age at the lumbar spine and up to the eighth decade at the femoral neck. Higher and lower lumbar spine values, as compared with the “Hispanic” population, were observed in Mexican mestizo women from the northern and southeastern regions, respectively. In conclusion, there are geographic differences in weight and height of Mexican women, and in BMD despite adjustment for weight. Received: 1 September 1999 / Accepted: 20 October 1999     

Long-Term Follow-up of Bone Mass after Orthotopic Liver Transplantation: Effect of Steroid Withdrawal from the Immunosuppressive Regimen

Glucocorticoids have been suggested to play a major role in transplantation-related osteopenia. In this study we assess the long-term changes and the effect of steroid withdrawal from the standard immunosuppressive regimen on bone mineral density (BMD) after orthotopic liver transplantation (OLT). Sixty-nine non-osteoporotic patients (20 women, 49 men), aged 48 ± 9.5 years (mean ± SD), and with a follow-up of 58.3 ± 23.2 months (range 24–121 months) were studied. Immunosuppressive treatment consisted of prednisone, cyclosporin A and azathioprine. In 41 patients (group A), prednisone was tapered and withdrawn after 36.2 ± 19.3 months (range 13–79 months), whereas in 28 patients (group B) prednisone was maintained. BMD in the spine (L1–L4) was serially measured by dual-energy X-ray absorptiometry (Hologic QDR 1000w) at baseline, before steroid withdrawal and at the end of study. Age- and sex-matched Z-scores of BMD were calculated. No differences were found in age, body mass index, time since OLT, or baseline BMD between the two groups. BMD had significantly increased in both groups at the end of follow-up period (group A, +8.1 ± 8.7%; group B, +3.2 ± 8.0%, p<0.05). However, the Z-score was significantly higher in group A than in group B at the end of study (–0.44 ± 1.05 vs –0.99 ± 0.77; p<0.05). BMD recovery was lower in pre-OLT biliary cirrhosis patients. Bone mass improvement was independent of the time since OLT in both groups, and of the time of steroid withdrawal in group A. Our data confirm that steroid withdrawal accelerates the recovery of bone mass in patients who have undergone a successful liver transplantation. Received: 17 April 2001 / Accepted: 1 August 2001     

Bone Mineral Density in Sixty Adult Patients with Marfan Syndrome

Sixty adult patients (40 women, 20 men) with Marfan syndrome (MFS) according to the Berlin criteria had a full clinical examination and bone mineral density (BMD) measurement by dual-energy X-ray absorptiometry of the hip and nondominant forearm. BMD was expressed as a Z-score and compared with the reference population of the Hologic database. In MFS men, BMD (g/cm²) was compared with the BMD of 45 normal tall Caucasian adults. Osteocalcin was measured by radioimmunoassay. In patients with MFS, BMD was compared between patients with and without previous fractures and according to the phenotypic severity of MFS. The mean age of the patients was 32.9 ± 9.3 years (women 32.5 ± 9.7, men 33.4 ± 8.6), mean height was 180.3 ± 10.3 cm (women 176.3 ± 9.2, men 188.1 ± 7.5) and mean body mass index 20.9 ± 3.6 kg/m² (women 20.8 ± 3.4, men 20.95 ± 3.97). Hyperlaxity score (Beighton criteria) was 6.9 ± 1.1. Six patients (10%) had a previous fracture. Thirty per cent of patients had had at least one previous operation for scoliosis, aortic dilatation or eye problems. BMD values in the 60 patients were as follows: Z-score of the hip, −1.26 ± 0.93, p<10⁻⁹ (neck, −0.93 ± 1.09, p<10⁻⁹; trochanter, −1.31 ± 0.85, p<10⁻⁹; intertrochanter, −1.39 ± 0.99, p<10⁻⁹; Ward’s triangle, −0.93 ± 1.88, p<10⁻⁹); Z-score of the radius: −1.6 ± 1.06, p<10⁻⁹ (1/3 proximal, −1.29 ± 1.03; mid-radius, −1.94 ± 1.04; ultradistal, −0.68 ± 1.1, p<10⁻⁹). The decrease in BMD was similar in men and women at both the hip and the radius. BMD in MFS patients was significantly decreased at cortical compared with trabecular sites (radius 1/3 proximal vs ultradistal, p<0.0001; total femur vs Ward’s triangle, p<0.0005). No difference in BMD was found between MFS patients with or without previous fractures and those with severe or less severe phenotypic expression of MFS. An influence of height and weight in MFS on BMD is suspected. Osteocalcin was not increased in our group of MFS patients. Thus both men and women with MFS have a significant deficit of BMD at the hip and radius. The decrease in BMD is present equally in both sexes and is more pronounced at predominantly cortical sites. In our group of patients we found no increase in fractures and no relation between decreased BMD and phenotypic expression of the syndrome. Received: 30 October 1998 / Accepted: 26 May 1999     

Osteocalcin Gene Polymorphism is Related to Bone Density in Healthy Adolescent Females

Recently a polymorphism was found in the human osteocalcin gene, and its association with bone mass was investigated in healthy postmenopausal Japanese women. The osteocalcin gene allelic variant HH was found to be overrepresented in women with osteopenia. The purpose of this study was to investigate whether the previously demonstrated polymorphism of the osteocalcin gene was related to bone mineral density (BMD; g/cm²) or osteopenia in a group of 97 healthy Caucasian adolescent females (aged 16.9 ± 1.2 years, mean ± SD). BMD of the left humerus, right femoral neck, lumbar spine and total body was measured using dual-energy X-ray absorptiometry. The relation between the allelic variants and bone density was analyzed as presence or absence of the H allele. Presence of the H allele was found to be related to a lower BMD of the humerus (0.97 vs 1.02, p = 0.03). There was also a strong tendency towards significance at the femoral neck (p = 0.06) and total body (p = 0.11). Using a multiple linear regression and including physical activity, weight, height and years since menarche, presence of the H allele was found to be an independent predictor of humerus BMD (β=−0.21, p<0.05) and femoral neck BMD (β=−0.23, p<0.01). Using logistic regression, presence of the H allele was also independently associated with a 4.5 times increased risk of osteopenia (p = 0.03) in the whole group. Osteopenia was defined as at least 1 SD lower bone density than the mean for the whole group of at least one of the BMD sites measured. We have demonstrated that the osteocalcin HindIII genotype is independently related to bone density in healthy adolescent females. The present study also suggests that presence of the H allele is predictive of osteopenia at an early age. Received: 31 January 2000 / Accepted: 25 April 2000     

Influence of Heredity and Environment on Bone Density in Adolescent Boys: A Parent–Offspring Study

The purpose of the present parent–offspring study was to investigate the influence of heredity and environment on bone density in young men. Another aim was to discover whether the same genetic factors influence bone mass, lean mass and muscle strength. Fifty families including a father, mother and one son were investigated. The mothers (aged 44.5 ± 4.4 years) and fathers (aged 47.1 ± 4.4 years) generally had a sedentary lifestyle with little physical activity. As a contrast, all but three of the sons (aged 17.0 ± 0.4 years) were active in ice hockey training. Bone mineral density (BMD, g/cm²) of the total body, head, lumbar spine and femoral neck was measured using dual-energy X-ray absorptiometry. Muscle strength of the hamstrings and quadriceps muscles was also measured in the boys. BMD values of different sites in the fathers, mothers and sons were adjusted for weight, height, age, and any significant influence of environment. Heritability estimates were obtained as regression coefficients with the boys’ adjusted BMD as dependent variable and the adjusted midparent bone density (father BMD + mother BMD/2) as independent variable. Accordingly, heritability explained 34–54% of the variation in the sons’ BMD. Midparent BMD of several sites also predicted the boys’ lean mass and quadriceps strength, and midparent–offspring differences in lean mass predicted midparent–offspring differences in BMD of the total body, head and spine (β= 0.30–0.51, p<0.05). The sons were found to have almost 30% higher femoral neck BMD than their fathers, and physical activity (hours/week) predicted BMD at several sites among the sons β= 0.26–0.34, p <0.05). In conclusion, heritability is a main determinant of the variance in BMD in young men. Based on the results we suggest that the same genetic factors may influence bone mass, lean mass and muscle strength by affecting body size. The present study also emphasizes the importance of physical activity for the development and maintenance of BMD in men. Received: 26 October 1998 / Accepted: 24 February 1999