Relationship between Fat Oxidation and Lactate Threshold in Athletes and Obese Women and Men

The first aim of this study was to determine the exercise intensity that elicited the highest rate of fat oxidation in sedentary, obese subjects (OB; n=10 men, n=10 women) compared with endurance athletes (AT; n=10 men, n=10 women). The second aim was to investigate the relationship between VO₂ at the intensity eliciting the highest rate of fat oxidation and the corresponding VO₂ at the lactate threshold. Peak oxygen consumption (VO_2peak) was determined in 20 AT and 20 OB using an incremental exercise protocol on a cycle ergometer. Based on their VO_2peak values, subjects completed a protocol requiring them to exercise for 20 min at three different workloads (55, 65 and 75% VO_2peak), randomly assigned on two separate occasions. The oxidation rates of fat and carbohydrate were measured by indirect calorimetry. The highest rates of fat oxidation were at 75 % VO_2peak (AT), and at 65 % VO_2peak (OB). The rate of fat oxidation was significantly higher in AT (18.2 ± 6.1) compared with OB women (10.6 ± 4.5 kJ min^-1·kg^-1) (p < 0.01). There was no significant difference in the rate of fat oxidation for the men (AT 19.7 ± 8.1 vs. OB 17.6 ± 8.2 kJ min^-1·kg^-1). AT reached LT at a significantly (p < 0.01) higher exercise intensity expressed in VO_2peak than obese subjects (AT women 76.4 ± 0.1, men 77.3 ± 0.1 vs. OB women, 49.7 ± 0.1, men 49.5 ± 0.1% VO_2peak). A significant correlation was found between VO₂ at LT and VO₂ (L·min^-1) eliciting the maximal rate of fat oxidation in athletes (women; r = 0.67; p = 0.03; men: r = 0.75; p = 0.01) but not in the obese. In summary, we observed higher rates of fat oxidation at higher relative work rates in AT compared with OB. A significant correlation was found between LT and the exercise intensity eliciting a high rate of fat oxidation in AT (r=0.89; p < 0.01) but not in OB. Cardiorespiratory fitness, defined as VO_2peak, seems to be important in defining the relationship between a high rate of fat oxidation and LT.

Key Points

• Within the tested intensities of 55, 65 and 75% VO_2peak athletes reached higher rates of fat oxidation at higher relative work rates compared with obese subjects.
• We found in obese women and men the intensity of the highest rate of fat oxidation at 65% VO_2peak.
• Between the lactate threshold and the intensity eliciting a high rate of fat oxidation a significant correlation was found in athletes but not in obese subjects.

Key words: Exercise intensity, substrate utilization, obesity, lactate threshold     

Relationship Between Training Status and Maximal Fat Oxidation Rate

This study aimed to compare maximal fat oxidation rate parameters between moderate- and low-performance runners. Eighteen runners performed an incremental treadmill test to estimate individual maximal fat oxidation rate (Fat_max) based on gases measures and a 10,000-m run on a track. The subjects were then divided into a low and moderate performance group using two different criteria: 10,000-m time and VO₂max values. When groups were divided using 10,000-m time, there was no significant difference in Fat_max (0.41 ± 0.16 and 0.27 ± 0.12 g.min^-1, p = 0.07) or in the exercise intensity that elicited Fat_max (59.9 ± 16.5 and 68.7 ± 10.3 % O₂max, p = 0.23) between the moderate and low performance groups, respectively (p > 0.05). When groups were divided using VO₂max values, Fat_max was significantly lower in the low VO₂max group than in the high VO₂max group (0. 29 ± 0.10 and 0.47 ± 0.17 g.min^-1, respectively, p < 0.05) but the intensity that elicited Fat_max did not differ between groups (64.4 ± 14.9 and 61.6 ± 15.4 %VO₂max). Fat_max or %VO₂max that elicited Fat_max was not associated with 10,000 m time. The only variable associated with 10,000-m running performance was %VO₂max used during the run (p < 0.01). In conclusion, the criteria used for the division of groups according to training status might influence the identification of differences in Fat_max or in the intensity that elicits Fat_max.

Key points

• The results of the present study suggest that the criteria used to categorize aerobic training status of subjects can influence the magnitude of differences in Fat_max.
• The Fat_max is similar between groups with similar 10,000-m running performance.
• The 10,000-m running performance seems to be associated with an increased ability to oxidize carbohydrate.

Key words: fat oxidation, running performance, indirect calorimetry     

The Association of Lean Mass and Fat Mass With Peak Bone Mass in Young Premenopausal Women

Total body mass is a major determinant of bone mass, but studies of the relative contributions of lean mass (LM) and fat mass (FM) to bone mass have yielded conflicting results. This is likely because of the use of bone measures that are not adequately adjusted for body size and, therefore, not appropriate for analyses related to body composition, which is also correlated with body size. We examined the relationship between body composition and peak bone mass in premenopausal women aged 18–30 yr using both size-dependent and size-adjusted measures of bone density and body composition, as well as statistical models adjusted for size-related factors. We measured total bone mass and areal bone density using dual-energy X-ray absorptiometry, and used established formulas to calculate estimates of volumetric (size-adjusted) bone density. LM tended to be positively associated with bone both before and after adjustment for size-related factors. FM and body fat percentage, however, were positively associated with size-dependent bone measures, but adjusting for size removed or reversed this association. These findings suggest that the association between bone mass and body composition, especially FM, is dependent on the bone measures analyzed, and that determining the most appropriate size-adjustment techniques is critical for understanding this relationship.     

Molecularly Defined Lactose Malabsorption,Peak Bone Mass and Bone Turnover Rate in Young Finnish Men

Lactose malabsorption (LM; adult-type hypolactasia), an autosomal recessive condition, results from the down-regulation of the activity of lactase enzyme in the intestinal wall. In previous studies the effect of LM on bone mass, bone turnover rate, development of osteoporosis and osteoporotic fractures has remained controversial. We have recently identified a single nucleotide polymorphism (SNP), a C to T change residing 13910 base pairs upstream of the lactase (LCT) gene at chromosome 2q21-22, which shows complete association with lactase persistence, with the C/C_–13910 genotype defining LM and the genotypes C/T_–13910 and T/T_–13910 lactase persistence. The present study was undertaken to examine the relationship of the C/T_–13910 polymorphism to peak bone mass, bone turnover rate, and stress fractures among young Finnish men. The study population comprised 234 young men, aged 18.3 to 20.6 years, 184 men were recruits of the Finnish Army, and 50 were men of similar age who had postponed their military service for reasons not related to health. Bone mineral content (BMC), density (BMD), and scan area were measured in the lumbar spine and upper femur by dual-energy X-ray absorptiometry (DXA). Blood was sampled for genotyping of the C/T_–13910 polymorphism and determination of serum 25-hydroxyvitamin D (25OHD), intact parathyroid hormone (iPTH), type I procollagen aminoterminal propeptide (PINP), and tartrate-resistant acid phosphatase 5b (TRACP5b). Second-void urine samples were collected for the determination of type I collagen aminoterminal telopeptide (NTX). The prevalence of the C/C_–13910-genotype of these young adults did not differ significantly from the corresponding population prevalence of C/C_–13910 (17.1% vs 18.1%) among Finnish blood donors. Fifteen recruits of the army experienced a stress fracture; 3 of them (20%) had the C/C_–13910-genotype. Calcium intake was similar for the three genotypes as were the unadjusted BMCs, scan areas, and BMDs at different measurement sites. The adjustments for age, height, weight, smoking, alcohol consumption, and physical exercise in the multiple regression analysis did not reveal any significant relationships between the lactase genotypes and BMDs at lumbar (P = 0.16), femoral neck (P = 0.99) or total hip (P = 0.96) sites. Serum 25OHD, iPTH, and bone marker levels were similar for the C/C_–13910 C/T_–13910 and T/T_–13910 genotypes. In summary, in young Finnish men, molecularly defined lactose malabsorption does not alter bone turnover rate and impair the acquisition of peak bone mass. Moreover, the C/C_–13910 genotype does not seem to be a risk factor for stress fractures in army recruits.N. Enattah and V.-V. Välimäki equally contributed to the study.     

Urethritis in Men and Women

Urethritis is usually caused by sexually transmissible organisms. Sexually transmitted diseases (STDs) increase the risk of acquiring other STDs, which is why patients presenting with urethritis should generally be examined for other STDs as well, and examination and treatment of sexual partners are necessary. Standard diagnosis is made via stains of urethral swabs or urine, but modern microbiological diagnostic methods such as nucleic acid amplification techniques achieve higher diagnostic accuracy. In non-gonococcal urethritis, a causative organism can often not be isolated. Antibiotic treatment is usually based on current epidemiologic data.     

The Associations of Body Composition and Fat Distribution With Bone Mineral Density in Elderly Italian Men and Women

This study aimed to investigate the associations of body composition and fat distribution with bone mineral density (BMD) in elderly Italian subjects. In 866 women (age 64.2 ± 6.5 yr) and 168 men (age 65.1 ± 6.1 yr), we measured BMD at lumbar spine, at femur, at the total body, and at the right hand. In all subjects, we also measured sex hormones, 25-hydroxyvitamin D, bone markers, and calcium intake. In both men and women, all body composition parameters had significant positive correlations with BMD at all sites after adjusting for age only; after adjusting also for body weight only lean mass (LM) remained positively associated with BMD at all sites except BMD at lumbar spine. In males, LM was associated with BMD at all sites, whereas android fat was associated with BMD at lumbar spine, at femur, and at whole body. In females, fat mass (FM) was positively and age inversely associated with BMD at all sites, whereas gynoid fat and alkaline phosphatase were inversely associated with BMD at lumbar spine and at femur. In conclusion, the role of LM seems more important in males, whereas in women the role of FM prevails with negative associations between gynoid fat and BMD.     

Cortisol Secretion and Rate of Bone Loss in a Population-Based Cohort of Elderly Men and Women

Although excessive glucocorticoids are a well-recognized cause of osteoporosis, little is known about the role of endogenous glucocorticoids in determining skeletal mass. We have performed a detailed study of the hypothalamic–pituitary–adrenal (HPA) axis to explore the relationships between cortisol secretion and adult bone mass in 151 healthy men and 96 healthy women aged 61 to 73 years. At baseline and 4-year follow-up, bone mineral density (BMD) was measured by dual energy X-ray absorptiometry (DXA) at the lumbar spine and proximal femur; a lifestyle questionnaire was completed; and height, weight, and waist and hip circumferences were measured. At follow-up subjects underwent a very low-dose (0.25 mg) dexamethasone suppression test, a low-dose (1 μg) short synacthen test, and a 24-hour urine collection for measurement of cortisol and its metabolites. In men, elevated peak plasma cortisol was associated with accelerated loss of mineral density in the lumbar spine (r = 0.16, P = 0.05). This relationship remained significant after adjustment for testosterone, estradiol, 25-hydroxyvitamin D, and parathyroid hormone levels (r = 0.22, P = 0.01) and after additional adjustment for age, (BM), activity, cigarette and alcohol consumption, and Kellgren/Lawrence score (r = 0.19, P = 0.03). In contrast in women, elevated peak plasma cortisol was associated with lower baseline BMD at the femoral neck (r = −0.23, P = 0.03) and greater femoral neck loss rate (r = 0.24, P = 0.02). There was no association between plasma cortisol concentrations after dexamethasone or urinary total cortisol metabolite excretion and bone density or bone loss rate at any site. These data provide evidence that circulating endogenous glucocorticoids influence the rate of involutional bone loss in healthy individuals.     

Large and Small Arterial Elasticity in Healthy Active and Sedentary Premenopausal Women

The purpose of this study was to compare large and small arterial elasticity in apparently healthy sedentary and recreationally active adult women, and to examine if age affects large and small arterial elasticity. This cross-sectional study consisted of 43 premenopausal women without overt cardiovascular disease (age = 43.4 ± 4.7 yrs; mean ± SD). The subjects were grouped into a sedentary group or a leisurely active group (30 min, 3d wk of low intensity) in addition to the following age groups: 35-40 years, n = 13; 41-45 years, n = 14; 46-54 years, n = 16. Subjects rested supine while pulse contour analysis was measured from the radial artery using an HDI/Pulsewave CR-2000 instrument (Hypertension Diagnostic, Inc.) to examine arterial elasticity in the large and small arteries. Activity level and menopausal status was based on self-report. There were no differences in large (14.5 ± 1.0 ml/mmHg x 10; 14.9 ± 0.9 ml/mmHg x 10; mean ± SD) and small (5.5 ± 0.5 ml/mmHg x 100; 6.4 ± 0.4 ml/mmHg x 100) arterial elasticity between the sedentary group and the recreationally active group, respectively. Large (12.8 ± 0.9 ml/mmHg x 10) arterial elasticity was lower in the oldest group (p = 0.008) compared to the youngest group (17.6 ± 5.9 ml/mmHg x 10). After adjusting for body mass index, large arterial elasticity (p = 0.022) remained lower in the oldest group. There was a trend for small arterial elasticity to be lower in the older group compared to the young group (p = 0.063). There was no difference in large and small arterial elasticity between healthy sedentary and recreationally active premenopausal women. This suggests that more strenuous physical activity may be necessary to gain beneficial effects on the vasculature. Large arterial elasticity is decreasing with advancing age independent of body mass index.

Key points

• There was no difference in large and small artery elasticity between healthy sedentary and recreationally active women.
• Large artery elasticity decreases with advancing age.
• Subjects with the highest systolic blood pressure had the largest decrease in large artery elasticity.

Key words: Arterial elasticity, premenopausal, body mass index, sedentary     

Correlates of Osteoprotegerin Levels in Women and Men

Osteoprotegerin (OPG) is a potent antiresorptive molecule that binds the final effector for osteoclastogenesis, receptor activator of NF-kB ligand (RANK-L). OPG production is regulated by a number of cytokines and hormones, including sex steroids, but there are few data on age and gender effects on circulating serum OPG levels, as well as possible relationships between OPG levels and bone turnover markers or bone mineral density (BMD). Thus, we measured serum OPG levels in an age-stratified, random sample of men (n= 346 age range, 23–90 years) and women (n= 304; age range 21–93 years) and related them to sex steroid levels, bone turnover markers and BMD. Serum OPG levels increased with age in both men (R= 0.39, p<0.001) and women (R= 0.18, p<0.01). Premenopausal women had higher OPG levels than men under age 50 years (171 ± 6 pg/ml vs 134 ± 6 pg/ml, respectively, p<0.001), whereas serum OPG levels were no different in postmenopausal women compared with men = 50 years (195 ± 7 pg/ml vs 188 ± 7 pg/ml, respectively, p= 0.179). OPG levels correlated inversely with serum bioavailable testosterone levels in men = 50 years (R=–0.27, p<0.001), but no associations were present with either estrogen or testosterone levels in the women. In the men, there was a trend for OPG levels to be associated positively with bone resorption markers and inversely with BMD. Collectively, the gender difference in OPG levels suggests that sex steroids may regulate OPG production in vivo, as has been found in vitro. Moreover, OPG production may also rise with increases in bone turnover, probably as a homeostatic mechanism to limit bone loss. Further studies directly testing these hypotheses should provide additional insights into the potential role of OPG in bone loss related to aging and sex steroid deficiency. Received: 14 August 2001 / Accepted: 20 November 2001     

Factors Affecting Peak Bone Density in Japanese Women

Both genetic and environmental factors have been shown to contribute to the determination of bone density. To clarify the interaction between genetic and environmental factors affecting peak bone mass, we investigated the correlation between bone mineral density (BMD) and physical constitution, vitamin D receptor (VDR) genotype, age, age of menarche, history of menstrual dysfunction, and exercise in 157 healthy young Japanese women. History of exercise and menstrual dysfunction were significant independent predictors of BMD. The VDR genotype also affects peak bone density. Exercise has been shown to increase BMD in a similar way for each VDR genotype including those women who have the particular genotype associated with low bone density. This data indicate that there are complex gene-environmental interactions particularly in relation to menstrual history, exercise, and genetic factors during childhood/adolescence that may have implications for the development of adult BMD in women. Received: 28 November 1997 / Accepted: 11 May 1998     

Comparison of VO2 Peak during Treadmill and Cycle Ergometry in Severely Overweight Youth

The purpose of this study was to compare peak cardiorespiratory parameters during treadmill and cycle ergometry in severely overweight youth. Twenty-one participants from the Committed to Kids Pediatric Weight Management program at the Louisiana State University Health Sciences Center volunteered. Participants completed peak treadmill and cycle ergometer tests on separate days. In order to examine reliability, six subjects completed a second treadmill test and seven subjects a second cycle test. Physical characteristics included the following: Age (yrs) 12.5 ± 2.8; Body weight (BW) (kg) 78.5 ± 27.0, Height (m) 1.56 ± 0.13; and % fat 42.8 ± 7.5. No statistical significant differences (p ≤ 0.05) were found between treadmill and cycle peak tests. Treadmill VO₂ peak (l·min^-1) averaged 1.57 ± 0.40 and cycle 1.46 ± 0.30 and VO₂ peak relative to BW 21.5 ± 4.1 and 20.3 ± 5.5 for treadmill and cycle ergometry, respectively. Therefore treadmill values were 7.0% and 5.6% higher than cycle values. In normal weight or children and adolescents at risk for overweight, treadmill values typically average from 7 to 12% higher than cycle values. Reliability of VO₂ peak as indicated by intraclass correlation coefficients ranged from 0.70 to 0.96 for a single or repeated tests. Intra individual variability averaged 0.5% for VO₂ peak (l·min^-1) during treadmill ergometry and 5.7% for cycle ergometry. Also, standard errors of measurement were low (40 to 90 ml min or 1.0 to 1.7 ml.kg^-1. min^-1) for the peak treadmill or cycle tests. In summary, our data suggest that both treadmill and cycle ergometry provide reliable methods for determining VO₂ peak in overweight youth.

Key Points

• Treadmill peak VO₂ higher than cycle ergometry in severely overweight youth.
• VO₂peak test-retest or single trial reliability high in both treadmill and cycle VO₂ peak.
• Standard errors of measure low for both treadmill and cycle VO₂peak.

Key Words: VO₂peak, severely overweight youth, treadmill, cycle ergometry     

Mediterranean Diet and Hip Fracture in Swedish Men and Women

A Mediterranean diet, known to have beneficial effects on cardiovascular health, may also influence the risk of hip fracture although previous studies present discrepant results. We therefore aimed to determine whether the rate of hip fracture was associated with degree of adherence to a Mediterranean diet. We combined two Swedish cohort studies consisting of 37,903 men and 33,403 women (total n = 71,333, mean age 60 years) free of previous cardiovascular disease and cancer who answered a medical and a food‐frequency questionnaire in 1997. A modified Mediterranean diet score (mMED; range, 0 to 8 points) was created based on high consumption of fruits and vegetables, legumes and nuts, whole grains, fermented dairy products, fish, and olive/rapeseed oil, moderate intake of alcohol, and low intake of red and processed meat. Incident hip fractures between January 1, 1998, and December 31, 2012, were retrieved from the National Patient Register. Hazard ratios (HRs) and 95% confidence intervals (CIs) adjusted for potential confounders were calculated using Cox proportional hazards regression. Differences in age at hip fracture were calculated using multivariable Laplace regression. During follow‐up, 3175 hip fractures occurred at a median age of 73.3 years. One unit increase in the mMED was associated with 6% lower hip fracture rate (adjusted HR = 0.94; 95% CI, 0.92 to 0.96) and with a 3‐month higher median age at hip fracture (50th percentile difference = 2.8 months; 95% CI, 1.4 to 4.2). Comparing the highest quintile of adherence to the mMED (6 to 8 points) with the lowest (0 to 2 points) conferred an adjusted HR of hip fracture of 0.78 (95% CI, 0.69 to 0.89) and a 12‐month higher median age of hip fracture (50th percentile difference = 11.6 months; 95% CI, 4.2 to 19.0). Results were similar in men and women. We conclude that higher adherence to a Mediterranean‐like diet is associated with lower risk of future hip fracture. © 2016 American Society for Bone and Mineral Research.     

Diminished Bone Strength Is Observed in Adult Women and Men Who Sustained a Mild Trauma Distal Forearm Fracture During Childhood

Children and adolescents who sustain a distal forearm fracture (DFF) owing to mild, but not moderate, trauma have reduced bone strength and cortical thinning at the distal radius and tibia. Whether these skeletal deficits track into adulthood is unknown. Therefore, we studied 75 women and 75 men (age range, 20 to 40 years) with a childhood (age <18 years) DFF and 150 sex‐matched controls with no history of fracture using high‐resolution peripheral quantitative computed tomography (HRpQCT) to examine bone strength (ie, failure load) by micro–finite element (µFE) analysis, as well as cortical and trabecular bone parameters at the distal radius and tibia. Level of trauma (mild versus moderate) was assigned using a validated classification scheme, blind to imaging results. When compared to sex‐matched, nonfracture controls, women and men with a mild trauma childhood DFF (eg, fall from standing height) had significant reductions in failure load (p < 0.05) of the distal radius, whereas women and men with a moderate trauma childhood DFF (eg, fall while riding a bicycle) had values similar to controls. Consistent findings were observed at the distal tibia. Furthermore, women and men with a mild trauma childhood DFF had significant deficits in distal radius cortical area (p < 0.05), and significantly lower dual‐energy X‐ray absorptiometry (DXA)‐derived bone density at the radius, hip, and total body regions compared to controls (all p < 0.05). By contrast, women and men with a moderate trauma childhood DFF had bone density, structure, and strength that did not differ significantly from controls. These findings in young adults are consistent with our observations in children/adolescents with DFF, and they suggest that a mild trauma childhood DFF may presage suboptimal peak bone density, structure, and strength in young adulthood. Children and adolescents who suffer mild trauma DFFs may need to be targeted for lifestyle interventions to help achieve improved skeletal health. © 2014 American Society for Bone and Mineral Research.     

Adiponectin and Peak Bone Mass in Men: A Cross-Sectional, Population-Based Study

Adiponectin, a protein classically known to be secreted by adipocytes, is also secreted by bone-forming cells. Results of previous studies have been contradictory as to whether serum adiponectin and bone mineral density (BMD) are associated. The aim of this study was to investigate a possible association between serum adiponectin and BMD in young, healthy men at a time of peak bone mass. BMD in the femoral neck, total hip, and lumbar spine were measured in this population-based cross-sectional study of 700 men aged 20–29 years participating in the Odense Androgen Study. Magnetic resonance imaging of femoral cortical thickness and bone marrow size was performed in a subsample of 363 participants. The associations between serum adiponectin and various bone measures were investigated by means of regression analyses with adjustment for potential confounding variables. An inverse association was found between serum adiponectin and total hip BMD and a direct between adiponectin and femoral bone marrow size (r = −0.092; P = 0.036 and r = 0.164; P = 0.003, respectively). Femoral muscle size may, at least in part, explain the association between adiponectin and total hip BMD. Serum adiponectin was inversely associated with total hip BMD in men at the time of peak bone mass, but this association may be explained by factors related to muscle size and function. The observed association between adiponectin and femoral bone marrow size was retained even after adjustment for potential covariates.     

Incidence of Distal Forearm Fracture in British Men and Women

Fracture of the distal forearm is one of the most frequent osteoporotic fractures. However, there are few data concerning its incidence in Britain. The aim of this study was to determine the incidence of distal forearm fracture in adult British men and women. Six centers took part in the study: Aberdeen, Hull, Nottingham, Portsmouth, Southampton and Truro. At each center, men and women aged 35 years and over with an incident distal forearm fracture and who resided in the catchment area of the main hospital at that center, were identified during a 12 month period. Incident fractures were identified from all possible point-of-contact sources in each locality, including accident and emergency records, fracture clinics, ward listings and plaster room registers. The population at risk was defined geographically according to postcode and the denominator obtained from 1991 census data mapped to these postcodes. During the 12 month study period, 3161 individuals with distal forearm fracture were identified. The age-adjusted incidence, age 35 years and over, was 36.8/10 000 person-years in women and 9.0/10 000 person-years in men. In women, the incidence of fracture increased progressively with age from the perimenopausal period, while in men the incidence remained low until later life. Fractures were more frequently left-sided (55.6%) and 19.4% of subjects required hospitalization. On the basis of these data we estimate that 71 000 adult men and women sustain a distal forearm fracture in Britain each year. Compared with previous British surveys the pattern of incidence with age appears to have changed in women, the reason for this is unclear. Received: August 2000 / Accepted: January 2001     

Skeletal Site Bone Mineral Density Heterogeneity in Women and Men

The heterogeneity of skeletal bone mineral density, measured on a single dual-energy X-ray absorptiometer, was examined in a large cohort of 7050 women and 702 men referred for investigation of osteoporosis. The men were significantly older (64.8 +/- 13.2 vs 60.2 +/- 11.5 years) and had an increased prevalence of nontraumatic fractures (ODR: 2.18; 95% CI: 1.82-2.61). The detection rate (sensitivity) for any osteoporosis (spine or hip) in women was 87.1% and 45.1% when assessed at the anteroposterior (AP) spine and femoral neck respectively. The corresponding osteoporosis detection rate in men was 69.3% and 67.5% at the AP spine and femoral neck respectively. Age-related AP spine degenerative changes increased significantly and at a similar rate for both women and men. Misclassification, that is osteoporosis (T-score < -2.5) at one site and normal (T-score > -1) bone mass at the other, was low in both genders (< 4.5%), but 3.1 (95% CI: 2.1-4.6) times more likely in women when the diagnosis was based on the femoral neck compared with the AP spine. Our findings suggest that there are significant age- and gender-related bone mineral density differences between the spine and hip skeletal sites which have to be considered if only one site is selected for investigation.