Association of change in fat and lean mass with incident cardiovascular events for women in midlife and beyond: A prospective study using dual-energy x-ray absorptiometry (DXA).

OBJECTIVE: To determine whether changes in fat and lean mass over time, quantified using dual-energy x-ray absorptiometry (DXA), are related to incident cardiovascular events. Previous studies using surrogate anthropometric methods have had inconsistent findings. STUDY DESIGN: Prospective, longitudinal observational study of women aged 40 to 80 randomly selected from the electoral roll and stratified into decades: 40-49, 50-59, 60-69 and 70-79 years. MAIN OUTCOME MEASURES: Changes in anthropometric measurements (body mass index and waist-to-hip ratio) and DXA-quantified fat mass and lean mass between the first and fifth years of the study. Incident cardiovascular events recorded from the sixth to the 12th year. RESULTS: In total 449 participants (87.9 %) were analyzed. A 10 % or greater decrease in total fat mass index was associated with a 67 % lower likelihood of any cardiovascular event (OR = 0.33, 95%CI 0.15-0.71); no association was observed for an increase. A 10 % or greater decrease in abdominal fat mass index was associated with a 62 % lower likelihood of incident stroke (OR = 0.38, 95%CI 0.16-0.91); no association was observed for an increase. A 10 % or greater decrease in appendicular lean mass index resulted in increased odds ratio of 2.91 for incident peripheral artery events (OR = 2.91, 95%CI 1.18-7.20). CONCLUSIONS: Reducing fat mass for women in midlife and beyond may decrease the risk of cardiovascular events. An increase in fat mass may not contribute to additional cardiovascular events. A reduction in limb muscle mass may provide an independent marker for cardiometabolic risk and peripheral artery disease. No independent association was found using anthropometric measurements and incident cardiovascular events.

Comparison of obesity and metabolic syndrome prevalence using fat mass index, body mass index and percentage body fat.

BACKGROUND: Accurate obesity classification is important so that appropriate intervention can be instituted to modify metabolic risk factors. Commonly utilized body mass index (BMI) and percentage body fat (PBF) are influenced by lean mass whereas fat mass index (FMI) measures only body fat. This study compares the prevalence of obesity and metabolic risk factors with FMI, BMI and PBF using DXA (dual-energy x-ray absorptiometry). METHODS: 489 women randomly recruited from the electoral roll were stratified into 4 age groups; 40-49, 50-59, 60-69 and 70-79 years from 2000 to 2001. Clinical data and DXA body composition were obtained. Statistical analyses were performed using Medcalc v15 (Ostend, Belgium) with significance level at p = 0.05 (two-tailed). RESULTS: There was higher prevalence of obesity using PBF compared to BMI and FMI (p<0.001). This difference was greater from age 50-59 (p<0.05) which may be explained by age-related lean mass loss. PBF over-classified obesity in over 35% of normal and 95% of overweight categories compared to FMI and BMI. BMI has a sensitivity of 78.9% and specificity of 98.3% for obesity using FMI as the standard. BMI under-classified obesity in the overweight category by 14.9% compared to FMI. There was no difference in diabetes, dyslipidemia, hypertension and metabolic syndrome prevalence within the BMI-obesity and FMI-obesity categories (p>0.05). CONCLUSION: PBF classified more obesity than BMI and FMI because of its low pre-determined threshold. The greater difference with PBF compared to BMI and FMI from the 50-59 decade onwards can be attributed to age-related lean mass loss. BMI had the lowest sensitivity for obesity diagnosis. BMI under-classified obesity in the overweight category compared to FMI due to its inability to differentiate lean mass. However, there was no significant difference in the prevalence of metabolic risk factors between BMI and FMI-obesity categories indicating that fat location may influence metabolic dysregulation.

A 5-year longitudinal study of changes in body composition in women in the perimenopause and beyond.

OBJECTIVE: Most studies of the age-related changes in body composition are cross-sectional in design: there have been few longitudinal studies. The aim of this 5-year study was to document body composition changes in perimenopausal and older women. STUDY DESIGN: Prospective, longitudinal observational study. METHODS: 489 women were randomly selected from the electoral roll and stratified into 4 age groups by decade: 40-49, 50-59, 60-69 and 70-79 years. Dual-energy x-ray absorptiometry (DXA) was performed in the first and fifth years of the study. Total body mass (TBM), total fat mass (TFM), total lean mass (TLM), abdominopelvic fat mass, and appendicular fat and lean mass were determined. RESULTS: There were significant increases in TBM (p < 0.001), TFM (p < 0.01), TLM (p < 0.05), arm fat mass (p < 0.05), leg fat mass (p < 0.001) and leg lean mass (p < 0.05) within the 40-49 age decade. TBM, TFM and abdominopelvic fat started to decline from the 50-59 decade. Abdominopelvic fat reduction was significant from the 50-59 decade to the later decades (p = 0.05 to p < 0.001). Arm lean mass showed a significant reduction from the 50-59 decade (p < 0.01). Leg lean mass declined from the 60-69 decade, reaching significance in the 70-79 decade (p = 0.05). CONCLUSION: TFM and abdominopelvic fat declined from the 50-59 age decade, which is earlier than is suggested in the literature. Conversely, the decline in appendicular lean mass with age occurred later, from the 50-59 decade, with earlier and greater loss in the arms, which has implications for exercise strategies to maintain muscle mass from midlife on.

The Role of Minor Pheromone Components in Segregating 14 Species of Longhorned Beetles (Coleoptera: Cerambycidae) of the Subfamily Cerambycinae.

We present research on the chemical ecology of 14 species of longhorned beetles (Coleoptera: Cerambycidae), in four tribes of the subfamily Cerambycinae, conducted in east-central Illinois over 8 yr. Adult males produce aggregation-sex pheromones that attract both sexes. Twenty independent field bioassays explored the pheromone chemistry of the species and tested the possible attractive or antagonistic effects of compounds that are not produced by a given species, but are pheromone components of other species. Analyses of beetle-produced volatiles revealed compounds that had not been reported previously from several of the species. The most common pheromone component was (R)-3-hydroxyhexan-2-one, but pheromones of some species included isomers of the related 2,3-hexanediols. Males of the congeners Phymatodes amoenus (Say) and Phymatodes testaceus (L.) produced pure (R)-2-methylbutan-1-ol. Enantiomers of 2-methylbutan-1-ol also proved to be powerful synergists for Megacyllene caryae (Gahan), Sarosesthes fulminans (F.), and Xylotrechus colonus (F.). The major components of pheromone blends were consistently present in collections of headspace volatiles from male beetles, and only the major components were inherently attractive to a subset of species when tested as single components. Minor components of some species acted as powerful synergists, but in other cases appeared not to influence attraction. Among the minor components identified in headspace extracts from males, 2,3-hexanedione and 2-hydroxyhexan-3-one appeared to be analytical artifacts or biosynthetic by-products, and were neither attractants nor synergists. The antagonistic effects of minor compounds produced by heterospecific males suggest that these compounds serve to maintain prezygotic reproductive isolation among some species that share pheromone components.

Evaluation of Methods Used in Testing Attraction of Cerambycid Beetles to Pheromone-Baited Traps.

Here, we describe several field experiments that evaluated potential problems with current methods of trapping cerambycid beetles using panel traps baited with synthesized pheromones. Positioning traps at least 5 m apart in linear transects was effective in preventing unbaited traps from intercepting beetles that were flying to baited traps, which would result in interference between treatments. There was no evidence that traps baited with a strong attractant drew beetles away from traps baited with weaker attractants, which would lead to the erroneous conclusion that the latter have no activity. Unbaited panel traps were minimally attractive to cerambycid beetles, and unlikely to intercept them passively in flight. Finally, dose-response experiments revealed that trap catch of cerambycids was positively associated with pheromone release rates. Overall, our results generally validated current methods of trapping cerambycids using traps baited with pheromones.

Influence of Fermenting Bait and Vertical Position of Traps on Attraction of Cerambycid Beetles to Pheromone Lures.

Because larvae of cerambycid beetles feed within woody plants, they are difficult to detect, and are readily transported in lumber and other wooden products. As a result, increasing numbers of exotic cerambycid species are being introduced into new regions of the world through international commerce, and many of these species pose a threat to woody plants in natural and managed forests. There is a great need for effective methods for detecting exotic and potentially invasive cerambycid species, and for monitoring native species for conservation purposes. Here, we describe a field experiment in east-central Illinois which tested whether attraction of beetles to a blend of synthesized cerambycid pheromones would be enhanced by volatiles from fermenting bait composed of crushed fruit, sugars, yeast, and wood chips. A second experiment tested the same treatments, but also assessed how trap catch was influenced by the vertical position of traps within forests (understory versus within the canopy). During the two experiments, 885 cerambycid beetles of 37 species were caught, with Xylotrechus colonus (F.) (subfamily Cerambycinae) being the most numerous (∼52% of total). Adults of several cerambycid species were significantly attracted by the pheromone blend, but the fermenting bait significantly enhanced attraction only for X. colonus and Graphisurus fasciatus (Degeer) (subfamily Lamiinae). Traps in the forest understory caught the greatest number of X. colonus and G. fasciatus, whereas more adults of the cerambycine Neoclytus mucronatus mucronatus (F.) were caught in the forest canopy rather than the understory.

2R,3S)-2,3-Octanediol, a Female-Produced Sex Pheromone of Megopis costipennis (Coleoptera: Cerambycidae: Prioninae).

During field screening trials of a number of known cerambycid pheromones in China, males of Megopis costipennis (White) (Coleoptera: Cerambycidae: Prioninae: Callipogonini) were found to be specifically attracted to racemic anti-2,3-octanediol, suggesting that one of the enantiomers of this compound might be a female-produced sex pheromone of this species. Analysis of volatiles produced by beetles of both sexes confirmed this hypothesis: females produced (2R,3S)-2,3-octanediol, whereas males did not, and in coupled gas chromatography­electroantennogram detection analyses, antennae from male beetles responded strongly to this compound. In field trials, males were equally attracted to traps baited with either (2R,3S)-2,3-octanediol or racemic anti-2,3-octanediol, indicating that the enantiomeric (2S,3R)-2,3-octanediol does not antagonize attraction to the naturally produced enantiomer. Thus, the more economical racemic anti-2,3-octanediol can be used for trap baits for this species. Homologous 2,3-hexanediols previously had been identified as sex pheromones or sex attractants of prionine species in the genus Tragosoma Audinet-Serville of the tribe Meroscelisini.

(2S,4E)-2-Hydroxy-4-octen-3-one, a Male-Produced Attractant Pheromone of the Cerambycid Beetle Tylonotus bimaculatus.

We report the identification of a novel pheromone structure from males of the cerambycid beetle Tylonotus bimaculatus Haldeman (Cerambycinae: Hesperophanini), a species native to eastern North America. Volatiles collected from adult males contained (2S,4E)-2-hydroxyoct-4-en-3-one (71%), (3R,4E)-3-hydroxyoct-4-en-2-one (15%), (E)-4-octen-2,3-dione (13%), and 2,3-octanedione (1.5%). Four independent field bioassays with synthetic compounds confirmed that adults of both sexes were attracted by the racemate of the major component, (E)-2-hydroxyoct-4-en-3-one. No other cerambycid species were attracted in significant numbers. Attraction of both sexes is consistent with the male-produced pheromones of many other species in the subfamily Cerambycinae, but T. bimaculatus is unusual in having a pheromone chemistry that is so far unique among species in that subfamily.

Cerambycid Beetle Species with Similar Pheromones are Segregated by Phenology and Minor Pheromone Components.

Recent research has shown that volatile sex and aggregation-sex pheromones of many species of cerambycid beetles are highly conserved, with sympatric and synchronic species that are closely related (i.e., congeners), and even more distantly related (different subfamilies), using the same or similar pheromones. Here, we investigated mechanisms by which cross attraction is averted among seven cerambycid species that are native to eastern North America and active as adults in spring: Anelaphus pumilus (Newman), Cyrtophorus verrucosus (Olivier), Euderces pini (Olivier), Neoclytus caprea (Say), and the congeners Phymatodes aereus (Newman), P. amoenus (Say), and P. varius (F.). Males of these species produce (R)-3-hydroxyhexan-2-one as their dominant or sole pheromone component. Our field bioassays support the hypothesis that cross attraction between species is averted or at least minimized by differences among species in seasonal phenology and circadian flight periods of adults, and/or by minor pheromone components that act as synergists for conspecifics and antagonists for heterospecifics.

Impact of reassociation with a coevolved herbivore on oviposition deterrence in a hostplant.

Although selection by herbivores for increased feeding deterrence in hostplants is well documented, selection for increased oviposition deterrence is rarely examined. We investigated chemical mediation of oviposition by the parsnip webworm (Depressaria pastinacella) on its principal hostplant Pastinaca sativa to determine whether ovipositing adults choose hostplants based on larval suitability and whether hostplants experience selection for increased oviposition deterrence. Webworms consume floral tissues and florivory selects for increased feeding deterrents; moths, however, oviposit on leaves of pre-bolting plants. Exclusive use of different plant parts for oviposition and larval feeding suggests oviposition should select for increased foliar deterrents. Recent webworm colonization of New Zealand (NZ) allowed us to assess phenotypic changes in foliar chemicals in response to webworm oviposition. In a common garden experiment, we compared NZ populations with and without a history of infestation from 2004 to 2006 for changes in leaf chemistry in response to oviposition. Three leaf volatiles, cis- and trans-ocimene, and ß-farnesene, elicit strong responses in female moth antennae; these compounds were negatively associated with oviposition and are likely oviposition deterrents. Leaf ß-farnesene was positively correlated with floral furanocoumarins that deter florivory; greater oviposition on plants with low floral furanocoumarins indicates that moths preferentially oviposit on parsnips most suitable for larval growth. Unlike florivory, high oviposition on leaves did not lower plant fitness, consistent with the fact that NZ parsnip foliar chemistry was unaffected by 3-6 years of webworm infestation. Thus, in this system, selection by ovipositing moths on foliar chemistry is weaker than selection by larvae on floral chemistry.

Seasonal phenology of the cerambycid beetles of east-central Illinois.

We summarize field data on the species composition and seasonal phenology of the community of cerambycid beetles of east-central Illinois. Data were drawn from field bioassays conducted during 2009 - 2012 that tested attraction of adult beetles of diverse species to a variety of synthetic pheromones and host plant volatiles. A total of 34,086 beetles of 114 species were captured, including 48 species in the subfamily Cerambycinae, 41 species in the Lamiinae, 19 species in the Lepturinae, two species in the Spondylidinae, and one species each in the Necydalinae, Parandrinae, Prioninae, and the Disteniidae. Most of the best-represented species were attracted to pheromones that were included in field experiments, particularly species that use (R)-3-hydroxyhexan-2-one as a pheromone component. The species captured, and their patterns of abundance and seasonal phenology were similar to those in an earlier study conducted in Pennsylvania. The most abundant species identified in both studies included the cerambycines Elaphidion mucronatum (Say), Neoclytus a. acuminatus (F.), Neoclytus m. mucronatus (F.), and Xylotrechus colonus (F.). Cerambycine species became active in an orderly progression from early spring through late fall, whereas most lamiine species were active in summer and fall, and lepturine species were limited to summer. Potential cross attraction between some cerambycine species that shared pheromone components may have been averted by differences in seasonal activity period, and by minor pheromone components that acted as synergists for conspecifics and/or antagonists for heterospecifics. These results provide quantitative data on the abundance and seasonal phenology of a large number of species.

Blending synthetic pheromones of cerambycid beetles to develop trap lures that simultaneously attract multiple species.

We evaluated attraction of cerambycid beetle species to blends of known cerambycid pheromones to determine whether such blends could be used as effective trap lures for detecting and monitoring multiple species simultaneously. Pheromone-baited traps captured 1,358 cerambycid beetles of which 1,101 (81.1%) belonged to three species in the subfamily Cerambycinae: Neoclytus acuminatus (F.), Neoclytus mucronatus (F.), and Xylotrechus colonus (F.). Beetles of these species were significantly attracted to synthetic blends that contained their pheromone components (isomers of 3-hydroxy-2-hexanone, 2,3-hexanediol, or both), despite the presence of pheromone components of different species, including other isomers of 2,3-hexanediol, (E/Z)-6,10-dimethyl-5,9-undecadien-2-yl acetate, and citral. In some cases, attraction was partially inhibited by the pheromone components of heterospecific species, whereas for N. acuminatus, attraction was completely inhibited when blends contained (2R*,3S*)-hexanediol, the racemic mixture of diastereomers of its pheromone, (2S,3S)-hexanediol. Among the remaining beetles captured were three species in the subfamily Lamiinae: Astyleiopus variegatus (Haldeman), Graphisurus fasciatus (Degeer), and Lepturges angulatus (LeConte). All three lamiine species were previously known to be attracted to (E/Z)-6,10-dimethyl-5,9-undecadien-2-yl acetate and were captured in significant numbers by blends containing that compound. Our results suggest that different types of cerambycid pheromones can be combined to create effective multispecies lures for use in surveillance programs that target exotic cerambycid species.

Towards validation of use of an Australian reference database for the diagnosis of osteoporosis with DXA.

INTRODUCTION: Bone densitometry in Australia uses the data from the Geelong Osteoporosis Study for conversion of bone mineral density (BMD) to T-scores to diagnose osteoporosis based on the World Health Organization (WHO) classification criteria. An underlying assumption is that the bone status of women in Geelong city is representative of the rest of Australia. The aim of this study is to compare the prevalence of normal BMD, osteopenia and osteoporosis of sample Brisbane women to Geelong, and to assess the validity of the Geelong reference database for Australia-wide application. METHODS: The subjects were recruited as part of a longitudinal assessment of age-related changes in a random sample of women from Brisbane. The sample consisted of 503 women, aged between 40 and 79 years. Each subject had BMD measured at the lumbar spine and femoral neck. RESULTS: Using the WHO osteoporosis classification criteria based on T-scores, and the BMD cut-offs from the Geelong Study, the prevalence of normal BMD, osteopenia and osteoporosis was determined for the following age groupings, 40-44, 45-49, 50-54, 55-59, 60-64, 65-69 and 70-79, to match the Geelong Study for comparison. There were no systematic differences in the prevalence of normal BMD, osteopenia and osteoporosis in the Brisbane subjects compared to the Geelong Study. CONCLUSION: This finding supports the use of the Geelong data as the reference for the generation of T-scores for bone densitometry assessment for osteoporosis using dual-energy X-ray absorptiometry in Australia.

A novel method to quantify carotid artery stenosis by Doppler ultrasound: Using the continuity principle.

BACKGROUND AND PURPOSE: A novel method to quantify carotid artery stenosis by using the continuity principle was evaluated. It was hypothesized that the novel method improved the accuracy of carotid ultrasound in assessing carotid artery stenosis. METHODS: Forty-nine patients were retrospectively studied. They were at a high risk for stroke and myocardial infarction, with significant cardiovascular risk factors. They were studied by carotid ultrasound as well as by one of the accepted gold standard techniques (computed tomography, magnetic resonance imaging or angiography). The cross-sectional areas of the narrowed part of the carotid arteries were measured using the continuity principle, and the percentage stenosis was thus calculated. RESULTS: The analyses showed that the combination of the conventional and novel criteria (ie, classifying a case as significant only if its stenosis was 67% or greater and its peak systolic velocity was 130 cm/s or greater) conferred the highest accuracy in predicting significant carotid stenosis compared with the gold standard techniques. CONCLUSION: From a practical point of view, the combined criteria might be useful for improving the accuracy of carotid ultrasound in predicting significant carotid stenosis.

Evaluation of femur angle abduction/adduction and bone mineral density values.

Bone densitometry using fan-beam technology allows both femurs to be rapidly measured with the aid of a bilateral foot-positioning tool to keep both legs in internal rotation. The Lunar Prodigy system uses a bilateral foot-positioning tool with a fixed interpedal width. The aim of this study was to determine whether the small degrees of femur abduction and adduction introduced by a fixed interpedal width-positioning tool influences the femur bone mineral density (BMD) measurements. Two-hundred patients had the total femur (FTot), femoral neck (FN), femoral shaft (FS), and femoral trochanter (FT) BMD, and angles of femoral abduction and adduction measured. Of all subjects, 26.5% had an absolute difference in femur angulation of 1 degrees , 77.5% had 5 degrees and 97% had 10 degrees. There was no significant correlation between the right-to-left differences in femur angles and the absolute right-to-left differences in FTot, FN, FS, and FT BMD. The introduction of small degrees of femur angulation with the fixed interpedal width bilateral foot positioner does not significantly affect the measured BMD at the various femur regions.

Pubertal development and its influences on bone mineral density in Australian children and adolescents with cystic fibrosis.

BACKGROUND: Pubertal delay is thought to contribute to suboptimal peak bone mass acquisition in young people with cystic fibrosis (CF), leading to an increased fracture incidence. This study aims to compare pubertal development in young people with CF with that of a local healthy population and assess the influence it has on areal bone mineral density (aBMD). METHODS: Tanner stage, age of menarche, bone age (BA), sex hormone levels and aBMD were examined in 85 individuals with CF (aged 5.3-18.1 years, 39 females) and 100 local controls (5.6-17.9 years, 54 females). RESULTS: Tanner stage and age of menarche were not significantly different between controls and CF. Tanner stage-adjusted mean values for follicle stimulating hormone (FSH), luteinizing hormone (LH) and testosterone (T) were lower in males with CF (FSH: P = 0.004, LH: P = 0.01 and T: P = 0.002). Bone age was delayed in adolescents with CF compared to controls (chronological age-BA: controls = 0.13 years (SE = 0.16), CF = 0.95 years (SE = 0.22), P = 0.003). Areal bone mineral density (adjusted for age, sex, height and lean tissue mass) was not significantly different between CF and controls. Moderate negative correlations were found between delayed BA and weight (r = -0.41, P < 0.001) and height (r = -0.41, P < 0.001). CONCLUSIONS: There was no evidence of clinical pubertal delay or low aBMD (adjusted for short stature and lean tissue mass) in young people with CF when compared with a local population, despite lower nutritional markers, height and weight and delayed skeletal maturation.

Vitamin A levels in patients with CF are influenced by the inflammatory response.

BACKGROUND: Serum vitamin A, normally depressed in inflammatory conditions, is frequently low in people with CF. Vitamin A is important in respiratory epithelial regeneration and repair. We hypothesised that serum vitamin A would be associated with inflammation and disease severity. METHODS: Serum vitamin A (as retinol), C-reactive protein (CRP), vitamin E, 25-hydroxy vitamin D (25OHD), 1,25-dihydroxy vitamin D (1,25(OH)(2)D), weight, and lumbar spine bone mineral density (LSBMD) were measured in 138 subjects with CF (5-56 years) and 138 control subjects (5-48 years). FEV(1), presence of CF liver disease (CFLD) and hospital admissions were recorded in those with CF. RESULTS: Serum vitamin A level was lower in CF subjects than in controls (mean, 95% CI: 1.29, 1.0-1.37 vs. 1.80, 1.7-1.87 micromol/l, p < 0.0001), and inversely correlated with CRP (r(s) = -0.37, p < 0.0001). CF subjects with low vitamin A (45%) level had poorer FEV(1), weight z-score, LSBMD z-score, and higher CRP compared with those with normal levels. In the CF group CRP, vitamin E, 1,25(OH)(2)D, presence of CFLD, admissions, and age were associated with vitamin A level. CONCLUSIONS: Serum vitamin A is negatively associated with CRP in subjects with CF, consistent with normal population studies. It is important to distinguish between low serum vitamin A associated with the inflammatory response and that due to poor nutritional stores. The role of vitamin A in CF warrants further study, in the contexts both of chronic recurrent inflammatory disease and acute pulmonary exacerbation.

Precision of bone densitometry measurements: when is change true change and does it vary across bone density values?

The precision error of the bone densitometer is used to interpret significant change in bone mineral density (BMD) in serial studies. The precision error can be expressed as standard deviation (SD) or coefficient of variation (CV). The aims of this study are to determine the precision error over a range of BMD values and to demonstrate the application of the precision error in clinical practice. A bone phantom was used consisting of a perspex block with eight compartments containing varying amounts of hydroxyapatite powder to simulate a range of bone densities. The block was scanned 21 times and manual regions placed over each compartment to measure the BMD in each compartment. There were no significant differences in the variances or SD for all eight compartments, that is, over the range of BMD normally encountered in clinical practice. However, the calculated CV show a progressive fall in values as the BMD rises. Therefore, the SD should be used to calculate significant BMD change. In a practise with quality control procedures in place to detect calibration drift and with appropriately trained personnel, a change of approximately 0.05 g/cm2 is generally regarded as being a significant change at a 95% confidence level.

The diagnostic role of dual femur bone density measurement in low-impact fractures.

A high correlation has been documented between the left and right femoral bone mineral densities in the normal population. This suggests that dual femur measurements are not justified in clinical practice. This study evaluated whether this premise holds for subjects who have lost bone mass and have sustained fractures with minimal trauma. Seventy-eight women aged 31-83 years (mean=66 years) with previous low-impact fractures had both proximal femora measured using dual-energy X-ray absorptiometry. There were significant correlations between values in the left and right total hip (TH) (r=0.95; p<0.05) and in the left and right femoral neck (FN) (r=0.90; p<0.05). The mean differences between the left and right TH and FN densities were not significant. However, the range of the limits of agreement for the TH (-0.074 to 0.086 g/cm2) and FN (-0.115 to 0.105 g/cm2) were greater than the 95% confidence interval for true change for the TH (0.05 g/cm2) and FN (0.07 g/cm2). Any longitudinal BMD assessment therefore needs to measure the same proximal femur to get a reliable comparison. A one-tailed analysis showed that for the TH, 7.5% of subjects had a T-score discordance greater than or equal to 0.5 and 0.5% had a T-score discordance greater than or equal to 1. For the FN, 9% had a T-score discordance greater than or equal to 0.5 and 2.5% had a T-score discordance greater than or equal to 1. The use of dual femur measurements increases the diagnostic yield by about 10% in subjects with prior minimal trauma fractures.

Abnormalities of the PTH-vitamin D axis and bone turnover markers in children, adolescents and adults with cystic fibrosis: comparison with healthy controls.

Abnormalities of calcium and vitamin D metabolism in cystic fibrosis (CF) are well documented. We tested the hypothesis that alterations in calcium metabolism are related to vitamin D deficiency, and that bone resorption is increased relative to accretion in patients with CF. Calcitropic hormones, electrolytes, osteocalcin (OC) and bone alkaline phosphatase (BAP), (markers of bone mineralisation), urinary deoxypyridinoline [total (t) Dpd, a marker of bone resorption] and lumbar spine bone mineral density (LS BMD), expressed as a z-score, were measured in 149 (81 M) CF and 141 (61 M) control children aged 5.3-10.99 years, adolescents aged 11-17.99 years and adults aged 18-55.9 years. Data were analysed by multiple regression to adjust for age. In patients, FEV(1)% predicted and CRP (as disease severity markers), genotype and pancreatic status (PS) were recorded. The distribution of PTH differed between groups ( P<0.0001), with CF levels both below and above the control range. 25OH vitamin D (25OHD) was not different in control and CF subjects ( P=0.06). Active hormonal vitamin D (1,25(OH)(2)D) was lower in the CF group ( P<0.0001), not explained by 25OHD or disease severity, as was serum magnesium ( P<0.0001). OC was decreased in CF adults ( P=0.004), and tDpd increased in CF adolescents ( P=0.003) and adults ( P=0.03). The ratio of OC to tDpd (a measure of bone coupling) was similar in CF and control children, but decreased in CF adolescents ( P=0.04) and adults ( P=0.02), suggesting decreased overall bone accrual in CF adolescents and uncoupling of bone balance in adults. 1,25(OH)2D was weakly correlated with OC in CF children ( r=0.43, P=0.01), and with tDpd in CF and control adolescents ( r=0.33, P=0.05 and r=0.36, P=0.02, respectively); thus there was limited evidence of association of calcitropic hormones, which had an abnormal pattern in all age groups, with bone turnover. There was no association between calcitropic hormones or bone turnover markers and LS BMD z-score. Despite vitamin D sufficiency, abnormalities of calcium metabolism and bone turnover markers were still apparent and bone accretion was decreased relative to resorption in the CF adolescent and adult groups. These changes were not fully explained by disease severity or genotype, but are consistent with reports of decreased BMD and unique bone histomorphometry in older subjects with CF.