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Biomedical subjects

D A Hanley

Publications and source records attributed to D A Hanley.

At least 37 records · Page 2Linked to original sources
PubMed2000

Estimation of the prevalence of low bone density in Canadian women and men using a population-specific DXA reference standard: the Canadian Multicentre Osteoporosis Study (CaMos).

The Canadian Multicentre Osteoporosis Study (CaMos) is a prospective cohort study which will measure the incidence and prevalence of osteoporosis and fractures, and the effect of putative risk factors, in a random sample of 10,061 women and men aged > or = 25 years recruited in approximately equal numbers in nine centers across Canada. In this paper we report the results of studies to establish peak bone mass (PBM) which would be appropriate reference data for use in Canada. These reference data are used to estimate the prevalence of osteoporosis and osteopenia in Canadian women and men aged > or = 50 years. Participants were recruited via randomly selected household telephone listings. Bone mineral density (BMD) of the lumbar spine and femoral neck were measured by dual-energy X-ray absorptiometry using Hologic QDR 1000 or 2000 or Lunar DPX densitometers. BMD results for lumbar spine and femoral neck were converted to a Hologic base. BMD of the lumbar spine in 578 women and 467 men was constant to age 39 years giving a PBM of 1.042 +/- 0.121 g/cm2 for women and 1.058 +/- 0.127 g/cm2 for men. BMD at the femoral neck declined from age 29 years. The mean femoral neck BMD between 25 and 29 years was taken as PBM and was found to be 0.857 +/- 0.125 g/cm2 for women and 0.910 +/- 0.125 g/cm2 for men. Prevalence of osteoporosis, as defined by WHO criteria, in Canadian women aged > or = 50 years was 12.1% at the lumbar spine and 7.9% at the femoral neck with a combined prevalence of 15.8%. In men it was 2.9% at the lumbar spine and 4.8% at the femoral neck with a combined prevalence of 6.6%.

Absorptiometry, Photon↗
PubMed2000

Predicting subsequent bone density response to intermittent cyclical therapy with etidronate from initial density response in patients with osteoporosis.

We investigated whether an increase in lumbar spine bone mineral density (LS BMD) at 6 months or at 12 months could predict the response to intermittent cyclical therapy (ICT) with etidronate, defined in one of two ways: (i) an increase in LS BMD at 24 months (improvement) or (ii) an increase in LS BMD > or = 0.028 g/cm2 (significant improvement). The latter is a precision term calculated from test-retest values for LS BMD in osteoporotic patients. Two hundred and forty-seven patients (32 men; 5 premenopausal and 210 postmenopausal women) were followed for 24 months by dual-energy X-ray absorptiometry (DXA) and were not taking estrogen, calcitonin or fluoride during treatment with ICT-etidronate. One hundred and fifty patients had a LS BMD measurement after 6 months of treatment with ICT-etidronate and 205 patients had one at 12 months. Baseline characteristics (mean;SD) were as follows: age, 66;11 years; years since menopause, 21;10; number of vertebral fractures at baseline, 0.87;1.26; LS BMD T-score, -2.8; 1.2. After 24 months of treatment with ICT-etidronate, 81% of the patients had an improvement, and 55% had a significant improvement at the LS. Only 6% significantly lost bone (loss of 0.028 g/cm2 or more). The mean percent change from baseline in LS BMD was 5.1% (95% confidence interval 4.2% to 6.0%). The results for men and postmenopausal women were similar to those for the entire group. Accuracy and sensitivity were marginally, but not significantly, higher when response was predicted using 12 month versus 6 month LS BMD measurements. The positive predictive values of improvement at 6 or 12 months were 89% and 90% respectively for improvement at 24 months, and 66% and 68% for significant improvement at 24 months. Identification of nonresponders was less successful and similar at 6 months and 12 months. Forty percent and 39% of the patients, who had no improvement at 6 or 12 months respectively, also had no improvement at 24 months, i.e., were true negatives, while 77% and 71% had no significant improvement at 24 months. The results may reflect slow response in a small subgroup of patients rather than nonresponse; however, no response at 1 year might identify patients whose rate of response is sufficiently slow that alternative therapy is justified. These data demonstrate a good response rate to ICT-etidronate and may help reduce the need for follow-up BMD measurements in those who show an early improvement.

Absorptiometry, Photon↗
PubMed2000

Management of corticosteroid-induced osteoporosis.

OBJECTIVES: To educate scientists and health care providers about the effects of corticosteroids on bone, and advise clinicians of the appropriate treatments for patients receiving corticosteroids. METHODS: This review summarizes the pathophysiology of corticosteroid-induced osteoporosis, describes the assessment methods used to evaluate this condition, examines the results of clinical trials of drugs, and explores a practical approach to the management of corticosteroid-induced osteoporosis based on data collected from published articles. RESULTS: Despite our lack of understanding about the biological mechanisms leading to corticosteroid-induced bone loss, effective therapy has been developed. Bisphosphonate therapy is beneficial in both the prevention and treatment of corticosteroid-induced osteoporosis. The data for the bisphosphonates are more compelling than for any other agent. For patients who have been treated but continue to lose bone, hormone replacement therapy, calcitonin, fluoride, or anabolic hormones should be considered. Calcium should be used only as an adjunctive therapy in the treatment or prevention of corticosteroid-induced bone loss and should be administered in combination with other agents. CONCLUSIONS: Bisphosphonates have shown significant treatment benefit and are the agents of choice for both the treatment and prevention of corticosteroid-induced osteoporosis.

Adrenal Cortex Hormones↗
PubMed2000

Enhancement of bone mass in osteoporotic women with parathyroid hormone followed by alendronate.

Treatment of osteoporosis with PTH causes a marked increase in vertebral bone mineral density (BMD). However, this effect is rapidly reversed when the treatment is stopped. The purpose of the present study was to determine whether the bisphosphonate alendronate could preserve or enhance bone density in patients previously treated with PTH. Sixty-six postmenopausal osteoporotic women were treated for 1 yr with 50, 75, or 100 microg recombinant human PTH-(1-84) or placebo, and then were given 10 mg alendronate daily for an additional year. BMD was measured in the femoral neck, lumbar spine, and whole body. Markers of bone turnover included skeletal alkaline phosphatase, osteocalcin, and N-telopeptide. During the first year, changes in BMD (mean +/- SD) in women receiving PTH (all doses combined) were 7.1 +/- 5.6% (spine), 0.3 +/- 6.2% (femoral neck), and -2.3 +/- 3.3% (total body). After switching to alendronate for 1 yr in women who previously had received PTH, mean changes in BMD were 13.4 +/- 6.4% (spine), 4.4 +/- 7.2% (femoral neck), and 2.6 +/- 3.1% (whole body). In the subgroup of patients who had received the highest dose of PTH, the mean increase in vertebral BMD was 14.6 +/- 7.9%. All markers of bone turnover increased during treatment with PTH and decreased to below baseline after 1 yr of alendronate. In conclusion, sequential treatment of osteoporosis with PTH and alendronate results in an increase in vertebral bone density that is considerably more than has been reported with alendronate or estrogens alone. This combination of drugs may be a useful approach to maximizing bone density in women with vertebral osteoporosis.

Aged↗
PubMed2000

Etridronate therapy in the treatment and prevention of osteoporosis.

Etidronate disodium is an oral bisphosphonate compound known to reduce bone resorption through the inhibition of osteoclastic activity. This article is a review of its efficacy and safety in the treatment and prevention of postmenopausal and corticosteroid-induced osteoporosis. In general, studies of cyclical etidronate therapy (400 mg daily for 2 wk every 3 mo) have found a significant improvement in bone density. These studies have not been powered to study fracture incidence, but a reduced fracture rate has been found in some of the studies reviewed. Studies examining cyclical etidronate in the prevention of osteoporosis indicate it prevents early menopausal bone loss and is free of significant side effects. In both prevention of corticosteroid-induced osteoporosis and treatment of patients who have been on long-term corticosteroid therapy, cyclical etidronate appears to increase bone density and prevent further loss of bone. In summary, a review of available literature pertaining to the use of etidronate in prevention and treatment of primary and secondary osteoporosis has been presented. This review suggests etidronate, used as a cyclical therapy, is a safe and effective therapy. The weight of evidence suggests it is capable of reducing fracture risk in patients with osteoporosis. Increases in bone density at the spine and hip are not as pronounced as with some other bisphosphonates, particularly alendronate, but no direct clinical comparison trials of significant size or duration have been undertaken.

Adrenal Cortex Hormones↗
PubMed1999

Multinational, placebo-controlled, randomized trial of the effects of alendronate on bone density and fracture risk in postmenopausal women with low bone mass: results of the FOSIT study. Fosamax International Trial Study Group.

This randomized, double-masked, placebo-controlled trial evaluated the safety, tolerability and effects on bone mineral density (BMD) of alendronate in a large, multinational population of postmenopausal women with low bone mass. At 153 centers in 34 countries, 1908 otherwise healthy, postmenopausal women with lumbar spine BMD 2 standard deviations or more below the premenopausal adult mean were randomly assigned to receive oral alendronate 10 mg (n = 950) or placebo (n = 958) once daily for 1 year. All patients received 500 mg elemental calcium daily. Baseline characteristics of patients in the two treatment groups were similar. At 12 months, mean increases in BMD were significantly (p</=0.001) greater in the alendronate than the placebo group by 4.9% (95% confidence interval 4.6% to 5.2%) at the lumbar spine, 2.4% (2.0% to 2.8%) at the femoral neck, 3.6% (3.2% to 4.1%) at the trochanter and 3.0% (2.6% to 3.4%) for the total hip. The incidence of nonvertebral fractures was significantly lower in the alendronate than the placebo group (19 vs 37 patients with fractures), representing a 47% risk reduction for nonvertebral fracture for alendronate-treated patients (95% confidence interval 10% to 70%; p = 0.021). Incidences of adverse events, including upper gastrointestinal adverse events, were similar in the two groups. Therefore, for postmenopausal women with low bone mass, alendronate is well tolerated and produces significant, progressive increases in BMD at the lumbar spine and hip in addition to significant reduction in the risk of nonvertebral fracture.

Adult↗
PubMed1999

Short- and long-term outcome of total parathyroidectomy with immediate autografting versus subtotal parathyroidectomy in patients with end-stage renal disease.

A retrospective study was performed in 36 patients with end-stage renal disease (ESRD) comparing total parathyroidectomy followed by immediate autografting into the forearm (total PTX + IA) with parathyroidectomy (subtotal PTX) over a five-year period. Twenty-eight patients underwent subtotal PTX and 8 had total PTX + IA. The two surgical methods were evaluated with respect to preoperative severity of hyperparathyroidism, perioperative morbidity, and the incidence of recurrent hyperparathyroidism. Eleven patients in total (30.6%) developed recurrent hyperparathyroidism; 2/8 (25%) in the total PTX + IA group compared to 9/28 (32.1%) in the subtotal PTX group (p = 0.699). The median time to recurrence was longer in the total PTX + IA group (39 vs. 16 months), and the median long-term postoperative PTH value was lower (81 vs. 199 ng/l), but these differences did not reach statistical significance. In conclusion, the incidence of recurrent hyperparathyroidism is high regardless of surgical modality. However, total PTX + IA may produce more favorable results with respect to median postoperative PTH level and time to recurrence.

Alkaline Phosphatase↗
PubMed1996

Prevention and management of osteoporosis: consensus statements from the Scientific Advisory Board of the Osteoporosis Society of Canada. 2. The use of bone density measurement in the diagnosis and management of osteoporosis.

OBJECTIVE: To determine the best method of diagnosing osteoporosis and determining fracture risk and to promote standards in the use of bone densitometry and the reporting of results. OPTIONS: Methods of bone mineral density measurement: dual-energy x-ray absorptiometry (DXA), radiographic absorptiometry, single-photon absorptiometry, dual-photon absorptiometry, quantitative computed tomography, quantitative ultrasound, neutron activation analysis. The options of using bone densitometry in individual patient management and as a mass screening tool are also considered. OUTCOMES: Appropriate use of densitometry to promote accurate diagnosis and assessment of fracture risk and timely, appropriate treatment. EVIDENCE: Relevant clinical studies and reports were examined. Clinical practice in Canada was also considered. VALUES: Accurate assessment of osteoporotic fracture risk and diagnosis of osteoporosis and assuring low exposure to medical radiation were given a high value. BENEFITS, HARMS AND COSTS: Early diagnosis through bone density measurement allows proper management of osteoporosis to minimize injury and disability, improve quality of life and reduce the personal and social costs associated with the condition. Potential harms include radiation exposure and cost. The harms and costs of appropriate use of DXA are minimal compared with the harms and costs associated with osteoporosis. RECOMMENDATIONS: Bone mineral density should be measured only to assist in making a clinical management choice. DXA is the best method of measuring bone density and, thus, the best available indicator of osteoporotic fracture risk. Plain radiographs may supplement DXA if there is a specific reason for their use. Measurement of the lumbar spine and femoral neck is standard, but a different site or a single measurement is recommended in specific cases. Unless accelerated bone loss is suspected, DXA should be repeated every 2 to 4 years for patients receiving ovarian hormone therapy and 1 to 2 years for patients undergoing bisphosphonate therapy. Measurements and reporting of results must be standardized. Reports should refer to the World Health Organization's recommended definitions of osteopenia and osteoporosis and provide actual measurement and its relation to peak bone mass.

Aged↗
PubMed1996

Prevention and management of osteoporosis: consensus statements from the Scientific Advisory Board of the Osteoporosis Society of Canada. 8. Vitamin D metabolites and analogs in the treatment of osteoporosis.

OBJECTIVE: To review recent findings on the skeletal actions of vitamin D and to examine results of the latest clinical trials of vitamin D in the treatment of osteoporosis. OPTIONS: The vitamin D analog 1-alpha hydroxycholecalciferol (1 alpha-OH-D3); the vitamin D metabolite calcitriol. OUTCOMES: Fracture and loss of bone mineral density in osteoporosis; increased bone mass, prevention of fractures and improved quality of life associated with vitamin D therapies. EVIDENCE: Relevant laboratory and clinical studies and reports were examined. Greatest reliance was placed on recent large-scale, randomized, controlled trials; others were noted and their methods critiqued. Clinical practice in Japan was also considered. VALUES: Reducing fractures, increasing bone mineral density and minimizing side effects of treatment were given a high value. BENEFITS, HARMS AND COSTS: Vitamin D maintains the dynamic nature of bone and so presumably helps to keep it healthy. Calcitriol and 1 alpha-OH-D3 may be effective in increasing bone mass and preventing fractures in osteoporosis. Calcitriol may be an alternative treatment in the prevention and management of corticosteroid-induced osteoporosis. Possible side effects of vitamin D analogs and metabolites are hypercalcemia, hypercalciuria, renal calcification and renal stones. RECOMMENDATIONS: The use of 1 alpha-OH-D3 for the treatment of osteoporosis in Canada cannot be supported without larger and longer randomized, controlled clinical trials. Calcitriol appears to prevent vertebral fractures in patients with osteoporosis. More information is needed on its mechanism of action and efficacy in preventing hip fractures. Future studies should focus on comparisons with other effective therapies and on determining whether its effect on fractures is greater than that achieved through improved vitamin D nutrition. Patients taking calcitriol at dose levels required for antifracture effects should be monitored for serum and urine calcium response to the drug. Calcitriol should not be given to patients whose calcium intake is at current generally recommended levels. At present, prescription of calcitriol for the treatment of osteoporosis should be reserved for physicians with a special interest in the treatment of metabolic bone disease.

Aged↗
PubMed1996

Identification of classical, novel, and atypical protein kinase C isoenzymes in the bovine parathyroid.

Because phospholipid metabolism leading to the activation of protein kinase C (PKC) may play a key regulatory role in the degradation and secretion of PTH, we examined parathyroid cell fractions for the presence of various PKC isoenzymes. Hydroxylapatite chromatography identified the classical PKCs, alpha and beta, but not gamma in parathyroid cell extracts. Western blot analysis confirmed the presence of PKC alpha and beta in these extracts. Of the so-called novel PKCs, Western blot analysis revealed the presence of only one isoenzyme, novel PKC epsilon in parathyroid cell soluble extracts. Western blot analysis using an antibody to the C-terminus of the atypical isoenzyme, PKC zeta, identified a protein of lower molecular weight in addition to PKC zeta. This lower molecular weight protein presumably represents PKC lambda, which shares a high degree of C-terminal sequence similarity with PKC zeta. These findings suggest the possibility that members of all three groups of the PKC family are present and may play a regulatory role in the bovine parathyroid cell.

Animals↗
PubMed1995

Calcium-activated proteases in the bovine parathyroid gland: potential role in degradation of parathyroid hormone to peptide fragments.

Our studies suggest that protein kinase C is involved in low calcium (Ca2+)-stimulated secretion of parathyroid hormone (PTH) but not directly in high Ca(2+)-stimulated intracellular degradation of PTH to secreted carboxyl-terminal fragments (C-PTH), an important component of Ca(2+)-regulated PTH secretion. The present study was undertaken to determine the presence of calcium-activated proteases, 84 kDa (micro)-calpain and 80 kDa (milli)-calpain, in the bovine parathyroid, and whether they could degrade PTH to C-terminal fragments. Immunocytochemistry of bovine parathyroid tissue using antibodies raised against bovine heart micro- and milli-calpain detected both isoforms of calpain. Western blotting of total bovine parathyroid cell protein prepared from primary cell cultures confirmed the presence of both isoforms of calpain, demonstrated by specific milli- and micro-calpain bands. Purified bovine PTH (bPTH) was incubated in vitro with human erythrocyte micro-calpain and the cleavage products were separated by reverse-phase HPLC. Eluant fractions were assayed with an RIA with equimolar sensitivity to C-PTH and bPTH, and peak areas integrated. Micro-calpain produced a C-PTH peak from bPTH which co-eluted with the major C-PTH secreted by parathyroid cells in culture. C-PTH production by micro-calpain, expressed as per cent area under the curve, increased from 0% in the absence of either micro-calpain or Ca2+, to 71.5% when a 5:1 molar ratio of bPTH to calpain was used. Amino acid sequencing and analysis of the immunoreactive PTH cleavage products indicated the presence of two fragments of bPTH in the C-PTH peak, bPTH47-48 and bPTH69-84. In summary, both isoforms of calpain are present in the bovine parathyroid and calpains may play a role in the Ca(2+)-dependent degradation of PTH to secreted C-terminal fragments.

Amino Acid Sequence↗
PubMed1993

Differences in ankle joint complex range of motion as a function of age.

The purpose of this study was to determine whether gender- and age-related differences in ankle joint complex (AJC) range of motion (ROM) exist in children (range 9-13 years), adolescents (14-16 years), and young adults (17-20 years), and to compare these data with those published for older subjects (21-79 years) using the same protocol. A total of 120 subjects (58 males and 62 females) ranging in age from 9 to 20 years were tested for AJC ROM using a specifically designed 6 degrees of freedom fixture. All measurements were made with respect to a laboratory coordinate system, and represented assessment of active AJC ROM. Angular displacements for plantarflexion, dorsiflexion, inversion, eversion, abduction, and adduction were digitally recorded and compared. AJC ROMs of females aged 9 to 20 years were generally greater than those for males about all three orthogonal axes. Within each gender, there was a consistent trend for AJC ROM to decrease from a maximum at 14 to 16 or 17 to 20 years to a minimum after age 60 years. The average decrement was greater for females than for males. This study provided evidence to support the contention that age-related and gender differences in AJC ROM do exist. The possibility of minimizing the decline in AJC ROM with age requires further investigation.

Adolescent↗
PubMed1993

The calciotropic hormone response to changes in serum calcium during exercise in female long distance runners.

The purpose of this study was to evaluate the effects of 45 min of submaximal running on calciotropic hormone levels in female long distance runners. Fourteen long distance runners and six sedentary controls (less than three exercise sessions per week) had bone mineral density (BMD) of the lumbar spine (L2-L4), femoral neck, and tibia measured by dual photon absorptiometry. All of the sedentary controls and eight runners (NormR) had BMD values within the normal range for women of their age. The remaining six runners had BMD L2-L4 measures greater than 1 SD below normal values and were classified as the low bone density group (LowR). Subjects were tested for their calciotropic hormone response to submaximal running using both an oral calcium load (dairy product), to induce a significant elevation in serum calcium, and no calcium load. In both exercise tests, serum calcium rose in NormR and LowR, with a greater increase induced by the oral calcium load. In NormR, the increase in serum calcium resulted in decreased PTH levels, with small increases in calcitonin levels. In contrast, LowR showed significant (P < 0.05) increases in PTH levels, with concurrent decreases in calcitonin levels. The changes in calciotropic hormone levels were shown to be significantly associated with BMD. Our results suggest that in well trained female runners with low spinal bone density, long distance running may aggravate this condition through the effect of exercise-related elevations of PTH on bone turnover. Alterations in the homeostatic control mechanisms for calcium during exercise should also be considered in the clinical assessment of female runners with spinal osteopenia.

Adult↗
PubMed1993

Mechanical loading regime and its relationship to bone mineral density in children.

This study tested the hypothesis that differences in mechanical loading regime was important when evaluating the potential role of physical activity on bone density in children. Seventeen children competing regularly in weight-bearing sports producing loads of at least 3 times body weight (Impact Load) were matched for race, gender, stage of puberty, body weight, and average daily training time with children involved in competitive swimming (Active Load). Bone mineral density (BMD) was measured using dual photon absorptiometry at the lumbar spine (L2-L4) and femoral neck (FN), Tanner staging was used to assess puberty, diet was evaluated based on 3-d dietary records from two occasions, and a questionnaire assessed average daily nonweight-bearing hours. There were no significant differences in age (13.2 +/- 0.4 and 12.6 +/- 0.4), height (154.9 +/- 2.9 and 157.6 +/- 3.0), or weight (43.6 +/- 2.7 and 44.5 +/- 2.2) between Impact and Active Load groups. Impact Load children had significantly greater FN BMD (0.78 +/- 0.02) than Active Load children (0.72 +/- 0.02) and a tendency for greater BMD L2-L4; 0.70 +/- 0.03 and 0.66 +/- 0.03, respectively. These data indicate that children involved in sports producing significant impact loading on the skeleton had greater femoral neck bone density and a trend for greater spinal bone density, than children in sports producing loads to bone primarily through muscular contraction.

Adolescent↗
PubMed1993

Parathyroid hormone: regulation of synthesis and secretion.

Calcium homeostasis is essential for survival and is primarily achieved through the actions of parathyroid hormone. Parathyroid hormone secretion and synthesis are primarily regulated by serum calcium levels, although other factors such as vitamin D and neurotransmitters play a role. This review is intended to provide the reader with up to date information on the current state of basic cell regulation research into parathyroid function. While some mention of disease states is made, the focus of this review is on the calcium regulation of parathyroid hormone secretion at the molecular level. Individual sections will discuss calcium-sensing, signal transduction by calcium and other secretagogues, regulation of parathyroid hormone synthesis, and strategies of regulation of parathyroid hormone secretion by calcium. Particular emphasis is given to the calcium-stimulated degradation of parathyroid hormone within the parathyroid as one of the major pathways by which circulating levels of bioactive hormone are controlled.

Amino Acid Sequence↗
PubMed1992

Activation and inhibition of protein kinase C in cultured bovine parathyroid cells: effect on the release of C-terminal fragments of parathyroid hormone.

The response of the parathyroid gland to low Ca2+ may be mediated in part by protein kinase C (PKC). We assessed the effect of two PKC activators, SC-9 and SC-10, and one PKC inhibitor, H-7, on Ca(2+)-regulated PTH release and degradation in primary cultures of bovine parathyroid cells. Both SC-9 and SC-10 stimulated PTH release, compared to high Ca2+ alone, in parathyroid cells incubated in high Ca2+, with maximal PTH release of at least twofold occurring at a concentration of either activator of 10 nM (p less than 0.05). We have previously shown that another PKC activator, PMA, not only enhances PTH release in the presence of high Ca2+ but suppresses low Ca(2+)-stimulated PTH secretion. In the present study, neither SC-9 nor SC-10 caused a comparable suppression of PTH release at low Ca2+. However, the PKC inhibitor, H-7 (1 microM), blocked low Ca(2+)-stimulated (compared to the low Ca2+ control) PTH secretion by approximately 50% (p less than 0.01) and did not affect high Ca2+ suppression of PTH secretion. H-7 (1 microM) was able to oppose the stimulation of PTH release by the PKC activators SC-9, SC-10, and PMA at high Ca2+ and negated the PTH release-inhibiting effect of PMA at low Ca2+. Culture medium from these experiments was subjected to reversed-phase HPLC and the eluted fractions analyzed by RIA for the presence of intact and C-terminal fragments of PTH.(ABSTRACT TRUNCATED AT 250 WORDS)

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

Bone mineral density during puberty in western Canadian children.

To assess the influence of puberty and its associated changes in body weight and height on bone mineral density (BMD), lumbar spine (L2-L4) and femoral neck BMD were measured in 74 healthy, active children (9-16 years) using dual-photon absorptiometry. Competitive swimmers were recruited to minimize the potential effect variability in mechanical loading regime may have on bone density of the lumbar spine. Tanner staging was used to assess stage of puberty. Current dietary calcium intake was assessed by analysis of 6-day dietary records. Significant differences in spinal and femoral neck BMD occurred between early (Tanner 1 and 2) and late stages of puberty (Tanner 4 and 5), P < 0.05. A significant correlation was found between bone density and dietary calcium intake. However stepwise regression analyses demonstrated stage of puberty or body weight were the only factors which significantly affected spinal BMD, accounting for 77% and 68% of the variability respectively; while at the femoral neck, body weight accounted for 52% of the variability. These results demonstrate that when potential interacting factors are controlled for through regression analyses, differences in BMD occur mainly as a function of puberty and the associated gains in body weight.

Adolescent↗