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Summary: The aim of this birth cohort study was to determine whether early life factors (birth weight, breastfeeding, and maternal smoking) were associated with bone mass and fractures in 16-year-old adolescents. The results suggest that breastfeeding is associated with higher bone mass and lower fracture risk at age 16 but not in utero smoking or birth weight. Introduction: There are limited data on early life influences on bone mass in adolescence but we have previously reported in utero smoking, breastfeeding, and birth weight were associated with bone mass at age 8. Methods: Birth weight, breastfeeding intention and habit, and maternal smoking during pregnancy were assessed at phase one in 1988-1999 and by recall during phase two in 1996-1997. Bone mineral density (BMD) was measured by dual-energy X-ray densitometry. Fractures were assessed by questionnaire. Subjects included 415 male and female adolescents from Southern Tasmania representing 29 % of those who originally took part in a birth cohort study in 1988 and 1989. Results: Breastfeeding (assessed in a number of ways) was associated with a 2-3 % increase in BMD at all sites apart from the radius and around a one third reduction in fracture risk which persisted after adjustment for confounders. In univariate analysis, birth weight was associated with BMD at the hip, radius, and total body but this did not persist in multivariate analysis and there was no association with fracture. Smoking in utero had no association with BMD at any site or fracture. Conclusions: Breastfeeding is associated with a beneficial increase in bone mass at age 16 and a reduction in fracture risk during adolescence. The association previously observed at 8 years of age is no longer present for birth weight or smoking in utero. [ABSTRACT FROM AUTHOR]

Introduction: The association between hormonal contraceptive use and bone mineral density remains controversial. Hypothesis: Hormonal contraceptive use is positively associated with bone mass in young premenopausal women. Methods: Cross-sectional analysis of data collected from women aged 26-36 years ( n = 687) in the Childhood Determinants of Adult Health study-a longitudinal study investigating childhood determinants of cardiovascular disease, diabetes, and other chronic diseases in adulthood. Participants were not currently pregnant or breast-feeding. Contraceptive use was obtained by self-administered questionnaire. Women were categorized as combined oral contraceptive users ( n = 219), progestogen-only contraceptive users ( n = 43), and non-users of hormonal contraceptives ( n = 425). Bone mass was measured by quantitative ultrasound. Results: Compared with women who were not using any hormonal contraceptives, women using combined oral contraceptives had significantly higher values of broadband ultrasound attenuation (BUA), speed of sound, and quantitative ultrasound index. These associations remained after adjustment for confounders. Progestogen-only contraceptive users had higher BUA than non-users, but the differences were not statistically significant in this small group. Conclusion: Combined oral contraceptive use was associated with higher bone mass measured by quantitative ultrasound in this population-based sample of premenopausal women aged 26-36 while progestogen-only contraceptives appeared to have no deleterious effect on bone mass. [ABSTRACT FROM AUTHOR]

Objective: To assess the effect of phytoestrogens on bone turnover and growth in adolescent boys. Design: Randomized double-blind placebo-controlled trial. Setting: Single school in northwest Tasmania. Participants: Adolescent boys (treatment n = 69, placebo n = 59, mean age 16.8 y). Interventions: Six weeks of isoflavone supplementation (Novasoy, 50 mg daily of isoflavone equivalents). Bone turnover markers (bone specific alkaline phosphatase (BAP) and pyridinoline creatinine ratio (PYR)) were measured at baseline and follow-up. Results: Despite marked increases in urinary genistein and daidzein in the treatment arm (both P < 0.001), there were no significant differences in BAP, PYR or short-term height or weight change. This applied to both intention-to-treat and per protocol analysis. Neither was there a significant correlation between urinary genistein and daidzein levels and BAP or PYR. Conclusions: Phytoestrogen supplementation to the level of usual Japanese dietary intake has no measurable effect on bone turnover in adolescent boys. Longer-term studies of bone density may be desirable but it is unlikely that there will be a large effect in either girls or boys given the lower endogenous oestrogen levels in boys. [ABSTRACT FROM AUTHOR]

Discusses a study on vitamin D levels in prepubertal children in Southern Tasmania. Significance of vitamin D in bone development; Methodology; Results of the study.

Objectives : To determine the feasibility of a randomized controlled trial (RCT) examining outdoor walking on knee osteoarthritis (KOA) clinical outcomes and magnetic resonance imaging (MRI) structural changes. Method: This was a 24-week parallel two-arm pilot RCT in Tasmania, Australia. KOA participants were randomized to either a walking plus usual care group or a usual care control group. The walking group trained 3 days/week. The primary outcome was feasibility assessed by changes being required to the study design, recruitment, randomization, program adherence, safety, and retention. Exploratory outcomes were changes in symptoms, physical performance/activity, and MRI measures. Results: Forty participants (mean age 66 years (SD 1.4) and 60% female) were randomized to walking (n = 24) or usual care (n = 16). Simple randomization resulted in a difference in numbers randomized to the two groups. During the study, class sizes were reduced from 10 to 8 participants to improve supervision, and exclusion criteria were added to facilitate program adherence. In the walking group, total program adherence was 70.0% and retention 70.8% at 24 weeks. The walking group had a higher number of mild adverse events and experienced clinically important improvements in symptoms (e.g., visual analogue scale (VAS) knee pain change in the walking group: − 38.7 mm [95% CI − 47.1 to − 30.3] versus usual care group: 4.3 mm [− 4.9 to 13.4]). Conclusions: This study supports the feasibility of a full-scale RCT given acceptable adherence, retention, randomization, and safety, and recruitment challenges have been identified. Large symptomatic benefits support the clinical usefulness of a subsequent trial. Trial registration number: 12618001097235. Key Points • This pilot study is the first to investigate the effects of an outdoor walking program on knee osteoarthritis clinical outcomes and MRI joint structure, and it indicates that a full-scale RCT is feasible. • The outdoor walking program (plus usual care) resulted in large improvements in self-reported knee osteoarthritis symptoms compared to usual care alone. • The study identified recruitment challenges, and the manuscript explores these in more details and provides recommendations for future studies. [ABSTRACT FROM AUTHOR]

Objectives: To describe factors associated with prevalent and incident foot pain in a population-based cohort of older adults (n = 1092).Study Design: Longitudinal observational study.Main Outcome Measures: Prevalent foot pain, incident foot pain after 5 years.Methods: Potential correlates included demographic factors, anthropometry, leg strength, metabolic factors, steps per day (using pedometer), pain at 6 other sites, and psychological wellbeing. Data were analysed using log binomial models.Results: Participants were aged 50-80 years (mean 63 years), 49% male, mean body mass index (BMI) 27.8 ± 4.7 at baseline. The prevalence of foot pain at baseline was 38% and the incidence of new pain over 5 years was 20%. BMI, pain at other sites (neck, hands, knees, pain at three or more sites), and poorer psychological wellbeing were independently associated with baseline foot pain. Baseline BMI and pain in the neck, hands, and knees were independently associated with incident foot pain; but change in weight or BMI, total number of painful joints and psychological wellbeing were not. Self-reported diabetes and cigarette smoking were not associated with prevalent or incident foot pain.Conclusions: This study demonstrates that greater body weight and joint pain at multiple sites were consistently associated with prevalent foot pain and predict incident foot pain. Addressing excess body mass and taking a global approach to the treatment of pain may reduce the prevalence and incidence of foot pain in older adults. [ABSTRACT FROM AUTHOR]

Summary: This was the first study examining optimal vitamin D status for musculoskeletal health in middle-aged women. A 25-hydroxyvitamin D level of at least 29 to 33 nmol/L appears required for optimal musculoskeletal health, but the current cut-off of 50 nmol/L may be warranted. Introduction: This study aimed to determine whether cut-points exist for associations between serum 25-hydroxyvitamin D (25OHD) and musculoskeletal health outcomes in middle-aged women, below which greater 25OHD levels are associated with musculoskeletal health benefits and above which no such associations exist. Methods: This is a cross-sectional study of 344 women aged 36-57 years. Cut-points for associations of serum 25OHD with lumbar spine (LS) and femoral neck (FN) bone mineral density (BMD), lower limb muscle strength (LMS), timed up and go test (TUG), functional reach test (FRT), lateral reach test (LRT), and step test (ST) were explored using locally weighted regression smoothing and nonlinear least-squares estimation, and associations above and below the identified cut-points were estimated using segmented regression. Results: The prevalence of low 25OHD was 28 % (<50 nmol/L). Significant cut-points (nmol/L) were identified for FN BMD 31 (95 % confidence interval (CI): 18, 43), LS BMD 31 (17, 45), TUG 30 (24, 36), ST 33 (24, 31), FRT 31 (18, 43), and LMS 29 (8, 49) but not LRT (42 (−8, 93). Below these cut-points, there were beneficial associations between higher 25OHD level and each outcome, while above the cut-points, there were no beneficial associations. Conclusions: In middle-aged women, there are thresholds for associations between serum 25OHD concentrations and bone density and most balance measures, suggesting that 25OHD levels of at least 29 to 33 nmol/L are required for optimal musculoskeletal health in this population. The current cut-off of 50 nmol/L may be higher than needed for some outcomes but appears warranted overall. [ABSTRACT FROM AUTHOR]

Summary: This was the first study investigating both linear associations between lower limb muscle strength and balance in middle-aged women and the potential for thresholds for the associations. There was strong evidence that even in middle-aged women, poorer LMS was associated with reduced balance. However, no evidence was found for thresholds. Introduction: Decline in balance begins in middle age, yet, the role of muscle strength in balance is rarely examined in this age group. We aimed to determine the association between lower limb muscle strength (LMS) and balance in middle-aged women and investigate whether cut-points of LMS exist that might identify women at risk of poorer balance. Methods: Cross-sectional analysis of 345 women aged 36-57 years was done. Associations between LMS and balance tests (timed up and go (TUG), step test (ST), functional reach test (FRT), and lateral reach test (LRT)) were assessed using linear regression. Nonlinear associations were explored using locally weighted regression smoothing (LOWESS) and potential cut-points identified using nonlinear least-squares estimation. Segmented regression was used to estimate associations above and below the identified cut-points. Results: Weaker LMS was associated with poorer performance on the TUG (β −0.008 (95 % CI: −0.010, −0.005) second/kg), ST (β 0.031 (0.011, 0.051) step/kg), FRT (β 0.071 (0.047, 0.096) cm/kg), and LRT (β 0.028 (0.011, 0.044) cm/kg), independent of confounders. Potential nonlinear associations were evident from LOWESS results; significant cut-points of LMS were identified for all balance tests (29-50 kg). However, excepting ST, cut-points did not persist after excluding potentially influential data points. Conclusions: In middle-aged women, poorer LMS is associated with reduced balance. Therefore, improving muscle strength in middle-age may be a useful strategy to improve balance and reduce falls risk in later life. Middle-aged women with low muscle strength may be an effective target group for future randomized controlled trials. Trial registration: Australian New Zealand Clinical Trials Registry (ANZCTR) NCT00273260. [ABSTRACT FROM AUTHOR]

Summary: Sarcopenia may be diagnosed in the clinic using operational definitions based on low muscle mass or function. This prospective, population-based study revealed that sex-specific associations may exist between operational definitions of sarcopenia and falls in community-dwelling middle-aged and older adults. Introduction: The objective of this study is to verify associations between sarcopenia and falls risk and to determine changes in sarcopenia prevalence over 5 years in middle-aged and older men and women according to different anthropometric and performance-based operational definitions. Methods: N = 681 volunteers (48 % female; mean ± SD age 61.4 ± 7.0 years) participated in baseline and follow-up assessments (mean 5.1 ± 0.5 years later). Appendicular lean mass (ALM) was assessed by dual-energy X-ray absorptiometry, hand grip (HGS) and lower-limb (LLS) strength were assessed by dynamometry, and falls risk was determined using the physiological profile assessment. Anthropometric definitions (ALM/height squared [ALM-H], ALM/weight × 100 and a residuals method [ALM-R]) and performance-based definitions (HGS, LLS and upper- and lower-limb muscle quality [LMQ]) of sarcopenia were examined. The lowest 20 % of the sex-specific distribution for each definition at baseline was classified as sarcopenia. Results: Sarcopenia prevalence increased after 5 years for all operational definitions except ALM-H (men: −4.0 %; women: −5.5 %). Men classified with sarcopenia according to anthropometric definitions, and women classified with sarcopenia according to performance-based definitions, had significant increases in falls risk over 5 years (all P < 0.05) compared to individuals without sarcopenia. Significant sex interactions were observed for ALM-R, LLS and LMQ (all P < 0.05) definitions. Conclusions: Sarcopenia prevalence generally increases at a higher rate when assessed using performance-based definitions. Sarcopenia is associated with increases in falls risk over 5 years in community-dwelling middle-aged and older adults, but sex-specific differences may exist according to different anthropometric or performance-based definitions. [ABSTRACT FROM AUTHOR]

Summary: The relationship between social disadvantage and bone mineral density (BMD) is complex and remains unclear; furthermore, little is known of the relationship with vertebral deformities. We observed social disadvantage to be associated with BMD for females, independent of body mass index (BMI). A lower prevalence of vertebral deformities was observed for disadvantaged males. Introduction: The relationship between social disadvantage and BMD appears complex and remains unclear, and little is known about the association between social disadvantage and vertebral wedge deformities. We examined the relationship between social disadvantage, BMD and wedge deformities in older adults from the Tasmanian Older Adult Cohort. Methods: BMD and wedge deformities were measured by dual-energy X-ray absorptiometry and associations with extreme social disadvantage was examined in 1,074 randomly recruited population-based adults (51 % female). Socioeconomic status was assessed by Socio-economic Indexes for Areas values derived from residential addresses using Australian Bureau of Statistics 2001 census data. Lifestyle variables were collected by self-report. Regression models were adjusted for age, BMI, dietary calcium, serum vitamin D (25(OH)D), smoking, alcohol, physical inactivity, calcium/vitamin D supplements, glucocorticoids and hormone therapy (females only). Results: Compared with other males, socially disadvantaged males were older (65.9 years versus 61.9 years, p = 0.008) and consumed lower dietary calcium and alcohol (both p ≤ 0.03). Socially disadvantaged females had greater BMI (29.9 ± 5.9 versus 27.6 ± 5.3, p = 0.002) and consumed less alcohol ( p = 0.003) compared with other females. Socially disadvantaged males had fewer wedge deformities compared with other males (33.3 % versus 45.4 %, p = 0.05). After adjustment, social disadvantage was negatively associated with hip BMD for females ( p = 0.02), but not for males ( p = 0.70), and showed a trend for fewer wedge deformities for males ( p = 0.06) but no association for females ( p = 0.85). Conclusions: Social disadvantage appears to be associated with BMD for females, independent of BMI and other osteoporosis risk factors. A lower prevalence of vertebral deformities was observed for males of extreme social disadvantage. Further research is required to elucidate potential mechanisms for these associations. [ABSTRACT FROM AUTHOR]

Aim This study aims to describe the lifetime picture of vitamin D deficiency, as measured by serum 25( OH) D concentration, in Tasmania (latitude 43° S). Methods Five cross-sectional studies were used: a sample of primary schoolchildren ( n = 201, aged 7-8 years), two samples of adolescents (sample 1: n = 374, aged 15-18 years; sample 2: n = 136, aged 16-19 years), a sample of young to middle-aged adults ( n = 262, aged 19-59 years) and a sample of older adults ( n = 1092, aged 50-80 years). Results In winter/spring, approximately two-thirds of the adolescents and adults (young, middle-aged and older) had 25( OH) D levels ≤50 nmol/ L, and around 10% had 25( OH) D levels ≤25 nmol/L. The prevalence of vitamin D deficiency was much lower for primary schoolchildren (11.5% < 50 nmol/ L, 0.5% ≤ 25 nmol/ L). In summer/autumn, approximately one-third of the adolescents and adults had 25( OH) D levels ≤50 nmol/ L, and very few had 25( OH) D levels ≤25 nmol/L. For the adolescents and adults, even among those who reported the highest category of sun exposure, approximately 45% had 25( OH) D levels ≤50 nmol/ L in winter/spring. Conclusions Vitamin D deficiency was uncommon among our sample of primary school children but increased substantially during the teenage years and seemed to remain high throughout the rest of life, suggesting that mild vitamin D deficiency is endemic in Tasmania apart from in the very young. [ABSTRACT FROM AUTHOR]

Background: There is controversy about whether pain and radiographic osteoarthritis (ROA) predict subsequent cartilage loss. The aim of this study was to describe the relationship between ROA, pain and cartilage loss in the knee. Methods: We studied randomly selected subjects at baseline and approximately 2.9 years later ( n= 399). The presence of ROA was assessed at baseline with a standing anteroposterior semiflexed radiograph scored using the Osteoarthritis Research Society International atlas for osteophytes (OP) and joint space narrowing (JSN). Pain was assessed by the Western Ontario McMaster Osteoarthritis Index. Subjects' medial and lateral tibial cartilage volumes were determined by magnetic resonance imaging at both time points. Results: In cross-sectional analysis, both medial and lateral tibial cartilage volumes were lower in those with ROA. Any medial ROA predicted medial tibial cartilage loss (3.2% (standard deviation (SD) 5.6) vs 1.9% (SD 5.3) per annum) while any lateral ROA predicted both medial (4.0% (SD 6.0) vs 2.2% (SD 5.3) per annum) and lateral (3.5% (SD 5.8) vs 1.6% (SD 4.2) per annum) tibial cartilage loss (all P < 0.05). In multivariate analysis, JSN and OP at both medial and lateral sites had independent dose-response associations with tibial cartilage loss at both sites. Pain was an independent predictor of lateral, but not medial, tibial cartilage loss after taking ROA into account. Conclusions: Subjects with ROA (either JSN or OP) and, to a lesser extent, pain lose cartilage faster than subjects without ROA and the more severe the ROA the greater the rate of loss. These findings have implications for the design of clinical trials. [ABSTRACT FROM AUTHOR]

Summary: Thinness is a risk factor for fractures, but the effect of obesity on fracture risk is less clear. We found an association between measures of obesity and prevalence and number of vertebral deformities in women but not in men, in a cross-sectional study of 1,011 participants aged 50-80 years. Introduction: Low body weight is well recognised as a risk factor for fractures, but the association between overweight and fracture risk is less well described. This cross-sectional study describes the association between measures of obesity and vertebral deformities in 1,011 male and female participants in the Tasmanian Older Adult Cohort study. Methods: Vertebral deformities (anterior wedging) of T4-L4 were determined by morphometric dual-emission X-ray absorptiometry. Body fat was assessed as weight, body mass index (BMI), waist-hip ratio (WHR), waist circumference and DXA measures of trunk fat (in percent) and total fat mass. Results: The mean age of participants was 63 ± 7 years, and mean BMI was 28 ± 5. Prevalent thoracic vertebral deformities were associated with increasing weight [standardised β (Sβ) 0.29, p = 0.003], BMI (Sβ 0.33, p < 0.001), trunk fat (Sβ 0.20, p = 0.03), waist circumference (Sβ 0.19, p = 0.03) and fat mass (Sβ 0.23, p = 0.03), but not the WHR in women, and only with decreasing total fat mass in men. In addition, the number of vertebral deformities increased as weight, BMI or fat mass increased in women (all p < 0.05) but decreased with increasing total fat mass in men. Associations between fat mass and vertebral deformities were mainly linear, but there was some evidence of a threshold effect in women with a BMI ≥35. Conclusions: There is a deleterious association between increasing amounts of body fat in women but not in men and the prevalence and number of vertebral deformities, which may reflect loading of the thoracic spine. [ABSTRACT FROM AUTHOR]

We studied the association between osteoporotic fractures and prior non-melanoma skin cancer (NMSC, a biomarker for cumulative sun exposure). The risk of prior NMSC in our fracture cohort was significantly reduced (standardised incidence ratio 0.69, 95% CI 0.61, 0.78). Adequate lifetime sun exposure may be necessary to protect against osteoporotic fractures in later life. The relationship between cumulative sun exposure and osteoporotic fractures is uncertain. We aimed to study the association between non-melanoma skin cancer (NMSC), a marker of cumulative sun exposure, and osteoporotic fractures in an older cohort. A retrospective cohort study in southern Tasmania in people aged at least 50 years with incident radiographic fracture ( n = 2,283) was carried out. By record linkage to the Tasmanian Cancer Registry the cohort was followed backwards through time until the occurrence of NMSC or end-of follow-up. Relative risk was estimated by the standardised incidence ratio (SIR) using sex-, age- and calendar year-specific cancer incidence rates in southern Tasmania as reference. The incidence of prior NMSC in the fracture cohort was 31% lower than for the general population (SIR 0.69, 95% CI 0.61, 0.78). This effect was significant for most fracture subtypes except pelvic and wrist fractures and observed for both NMSC subtypes, squamous cell carcinoma and basal cell carcinoma. Older people with osteoporotic fractures may have had lifestyles linked to lower cumulative sunlight exposure. Achieving a balance between adequate lifetime sun exposure and protection against its adverse effects (such as fractures and skin cancer) may require assessment of individual risks. [ABSTRACT FROM AUTHOR]