Predictors of low bone mass in young Chinese women

published_or_final_versio

Transforming growth factor-betal gene polymorphisms and bone turnover, bone mineral density and fracture risk in Southern Chinese Women

published_or_final_versio

Psychological, social and health issues in Hong Kong women with osteoporotic fractures

published_or_final_versio

Inhaled corticosteroid therapy in bronchiectasis - a 12-month study

published_or_final_versio

The frequency of osteogenic activities and the pattern of intermittence between periods of physical activity and sedentary behaviour affects bone mineral content: the cross-sectional NHANES study

BACKGROUND: Sedentary behaviours, defined as non exercising seated activities, have been shown to have deleterious effects on health. It has been hypothesised that too much sitting time can have a detrimental effect on bone health in youth. The aim of this study is to test this hypothesis by exploring the association between objectively measured volume and patterns of time spent in sedentary behaviours, time spent in specific screen-based sedentary pursuits and bone mineral content (BMC) accrual in youth. METHODS: NHANES 2005–2006 cycle data includes BMC of the femoral and spinal region via dual-energy X-ray absorptiometry (DEXA), assessment of physical activity and sedentary behaviour patterns through accelerometry, self reported time spent in screen based pursuits (watching TV and using a computer), and frequency of vigorous playtime and strengthening activities. Multiple regression analysis, stratified by gender was performed on N = 671 males and N = 677 females aged from 8 to 22 years. RESULTS: Time spent in screen-based sedentary behaviours is negatively associated with femoral BMC (males and females) and spinal BMC (females only) after correction for time spent in moderate and vigorous activity. Regression coefficients indicate that an additional hour per day of screen-based sitting corresponds to a difference of −0.77 g femoral BMC in females [95% CI: -1.31 to −0.22] and of −0.45 g femoral BMC in males [95% CI: -0.83 to −0.06]. This association is attenuated when self-reported engagement in regular (average 5 times per week) strengthening exercise (for males) and vigorous playing (for both males and females) is taken into account. Total sitting time and non screen-based sitting do not appear to have a negative association with BMC, whereas screen based sedentary time does. Patterns of intermittence between periods of sitting and moderate to vigorous activity appears to be positively associated with bone health when activity is clustered in time and inter-spaced with long continuous bouts of sitting. CONCLUSIONS: Some specific sedentary pursuits (screen-based) are negatively associated with bone health in youth. This association is specific to gender and anatomical area. This relationship between screen-based time and bone health is independent of the total amount of physical activity measured objectively, but not independent of self-reported frequency of strengthening and vigorous play activities. The data clearly suggests that the frequency, rather than the volume, of osteogenic activities is important in counteracting the effect of sedentary behaviour on bone health. The pattern of intermittence between sedentary periods and activity also plays a role in bone accrual, with clustered short bouts of activity interspaced with long periods of sedentary behaviours appearing to be more beneficial than activities more evenly spread in time

Adaptation and conservation insights from the koala genome

The koala, the only extant species of the marsupial family Phascolarctidae, is classified as ‘vulnerable’ due to habitat loss and widespread disease. We sequenced the koala genome, producing a complete and contiguous marsupial reference genome, including centromeres. We reveal that the koala’s ability to detoxify eucalypt foliage may be due to expansions within a cytochrome P450 gene family, and its ability to smell, taste and moderate ingestion of plant secondary metabolites may be due to expansions in the vomeronasal and taste receptors. We characterized novel lactation proteins that protect young in the pouch and annotated immune genes important for response to chlamydial disease. Historical demography showed a substantial population crash coincident with the decline of Australian megafauna, while contemporary populations had biogeographic boundaries and increased inbreeding in populations affected by historic translocations. We identified genetically diverse populations that require habitat corridors and instituting of translocation programs to aid the koala’s survival in the wild

Efficacy and tolerability of alendronate once weekly in Asian postmenopausal osteoporotic women

BACKGROUND: Osteoporosis has become a major health problem worldwide, and the incidence is rising in Asian countries. The aminobisphosphonates are potent inhibitors of bone resorption and are currently the mainstay of treatment for postmenopausal osteoporosis. Dosing frequency will likely affect tolerability and adherence to treatment. OBJECTIVE: To assess the tolerability and efficacy of a once-weekly aminobisphosphonate preparation in improving bone mineral density (BMD) and bone turnover markers in osteoporotic Asian women. METHODS: Chinese postmenopausal women with osteoporosis were randomized to receive either alendronate 70 mg once weekly plus calcium carbonate 500 mg daily (n = 29) or calcium carbonate 500 mg daily (n = 29) for one year. BMD was measured by dual energy X-ray absorptiometry. Markers of bone formation and bone resorption included plasma total alkaline phosphatase and urine N-telopeptides. RESULTS: Treatment with alendronate 70 mg once weekly for one year resulted in significant BMD improvement of 6.1% at the spine, 5.6% at the femoral neck, and 3.5% at the total hip. There was no significant change in the BMD values in the calcium group (spine 1.4%, femoral neck -0.2%, total hip 0%). The BMD response in the alendronate group was significantly different from that in the calcium group at all time points, and the difference was detectable as early as after 3 months of treatment (ANOVA p < 0.001). The changes remained significant after adjusting for age, age at menarche, and years since menopause (p < 0.001). Similarly, the reductions in bone markers at 12 months were significantly different between the 2 treatment groups (plasma total alkaline phosphatase: alendronate 27.9%, calcium 5.4%; urine N-telopeptide: alendronate 55.6%, calcium 11.2%; both p < 0.001). The alendronate regimen was well tolerated, without significant adverse events. CONCLUSIONS: The results confirmed that once-weekly alendronate was efficacious in increasing BMD and reducing bone turnover and was well tolerated in Asian women.link_to_subscribed_fulltex

Determinants of peak bone mineral density and bone area in young women

Osteoporosis is a disease caused by compromised bone strength, and individuals with a high peak bone mass at a young age are likely to have a high bone mass in old age. To identify the clinical determinants of peak bone mass in young adult women, 418 southern Chinese women, aged 20-39 years, were studied. Low bone mass was defined as areal bone mineral density (aBMD) Z-score < -1 at either the spine or total hip. Within the cohort, 62 (19.0%) and 86 (26.4%) women had low aBMD at the spine and hip, respectively. Regression model analysis revealed that low body weight (<44 kg) was associated with an 8.3-fold (95% CI, 3.7-18.9) and a 6.8-fold (95% CI, 3.0-15.6) risk of having low aBMD at the spine and hip, respectively. Low body weight was also predictive of low volumetric BMD (vBMD) at the spine (odds ratio (OR) 7.8, 95% CI, 3.1-20.1) and femoral neck (OR 3.0, 95% CI, 1.3-7.1). A body height below 153 cm was associated with a 4.8-fold risk in the small L2-4 bone area (95% CI, 2.3-9.8) and a 3.9-fold risk in the small femoral neck area (95% CI, 1.9-8.1). Delayed puberty (onset of menstruation beyond 14 years) was associated with a 2.2-fold (95% CI, 1.0-4.9) increased risk of having low aBMD at the hip. Physical inactivity was associated with a 2.8-fold risk of low spine vBMD (OR 2.8, 95% CI, 1.1-6.7) and a 3.3-fold risk of low hip aBMD (95% CI, 1.0-10.0). Pregnancy protected against low spine aBMD (OR 0.4, 95% CI, 0.1-1.2) and spine vBMD (OR 0.1, 95% CI, 0.0-1.0), low femoral neck vBMD (OR 0.3, 95% CI, 0.1-1.1) and small L2-4 bone area vBMD (OR 0.3, 95% CI, 0.1-1.1). In conclusion, this study identified a number of modifiable determinants of low peak bone mass in young adult women. Maintaining an ideal body weight, engaging in an active lifestyle, and diagnosing late menarche may enable young women to maximize their peak bone mass and so reduce their risk of osteoporosis in later life. © Springer-Verlag 2005.link_to_subscribed_fulltex