Statin use, bone mineral density, and fracture risk: Geelong Osteoporosis Study

Background Recent data suggest that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) decrease fracture risk and increase bone mineral density (BMD).

Methods This cross-sectional study is set in southeastern Australia. We evaluated the association between statin use, fracture risk, and BMD in 1375 women (573 with incident fractures and 802 without incident fracture, all drawn from the same community). Fractures were identified radiologically. Medication use and lifestyle factors were documented by questionnaire.

Results Unadjusted odds ratio for fracture associated with statin use was 0.40 (95% confidence interval [CI], 0.23-0.71). Adjusting for BMD at the femoral neck, spine, and whole body increased the odds ratio to 0.45 (95% CI, 0.25-0.80), 0.42 (95% CI, 0.24-0.75), and 0.43 (95% CI, 0.24-0.78), respectively. Adjusting for age, weight, concurrent medications, and lifestyle factors had no substantial effect on the odds ratio for fracture. Statin use was associated with a 3% greater adjusted BMD at the femoral neck (P = .08), and BMD tended to be greater at the spine and whole body but did not achieve statistical significance.

Conclusion The substantial 60% reduction in fracture risk associated with statin use is greater than would be expected from increases in BMD alone.

Hormone therapy and risk of non-vertebral fracture : Geelong Osteoporosis Study

In this population-based study, we evaluated the association between exposure to hormone therapy (HT), bone mineral density (BMD) and the prevalence of non-vertebral fractures. The study was set in a region located in southeastern Australia where complete fracture ascertainment was determined from radiological reports. Current HT use for at least 6 months was ascertained in women with non-vertebral fractures [median age 70.9 years; inter-quartile range (IQR) 66.5–75.9 years] and randomly selected controls (median age 70.8 years; IQR 65.2–75.0 years). Current HT use was documented in 20 of 262 cases and 49 of 364 controls. The odds ratio (OR) for non-vertebral fracture associated with HT use was 0.53 (95% CI 0.31–0.92). HT use was associated with 2.6–7.5% higher BMD at axial and appendicular sites. HT use is associated with a halving of risk for non-vertebral fractures and higher BMD.

Calcium intakes among Australian women : Geelong Osteoporosis Study

Background: Dietary calcium deficiency may be a risk factor for osteoporosis.

Aims: To estimate habitual calcium intakes and prevalence of calcium supplementation among free-living Australian women and validate a calcium-specific food-frequency questionnaire.

Methods: Calcium intakes for 1045 randomly selected women (20–92 years) were estimated by questionnaire which was tested against estimates from four day weighed records kept by 32 randomly selected women.

Results: The mean difference between calcium estimates was not statistically significantly different from zero (mean difference=121 mg; standard deviation of differences=357 mg; p>0.05). There was moderate agreement (weighted κ=0.4) between methods in ranking subjects into tertiles of calcium intake. Mean dietary calcium intakes were 615 mg/day for 20–54 years, 646 mg/day for 55–92 years and 782 mg/day for lactating women. Seventy-six per cent of women aged 20–54 years, 87% of older and 82% of lactating women had intakes below the recommended dietary intake (RDI). There was no association detected between calcium intake and age. Dairy foods provided 79.0% of dietary calcium intake. Calcium supplements were used by 6.6% and multivitamins by a further 4.3% of women. Supplementation was independent of dietary calcium intake and more likely used by postmenopausal women.

Conclusions: Our results suggest that 76% of women consume less than the RDI even when supplemental calcium is included. Furthermore, 14% have less than the minimal requirement of 300 mg/day and would, therefore, be in negative calcium balance and at risk of bone loss. Despite advertising campaigns promoting better nutrition and increased awareness of osteoporosis, many women are failing to achieve an adequate calcium intake.

The population burden of fractures originates in women with osteopenia, not osteoporosis

Introduction : Osteoporosis is associated with increased risk for fracture. However, most postmenopausal women have bone mineral density (BMD) within the normal or osteopenic range. The aim of this study was to determine the proportion of the population burden of fragility fractures arising from women at modest risk for fracture.

Methods : We measured baseline BMD in a population-based random sample of 616 postmenopausal women aged 60–94 years and followed these individuals for a median of 5.6 years (IQR 3.9–6.5) to determine the incidence of fractures according to age, BMD and the presence of a prior fracture.

Results : Based on WHO criteria, 37.6% of the women had normal total hip BMD, 48.0% had osteopenia and 14.5% had osteoporosis. The incidence of fracture during follow-up was highest in women with osteoporosis, but only 26.9% of all fractures arose from this group; 73.1% occurred in women without osteoporosis (56.5% in women with osteopenia, 16.6% in women with normal BMD). Decreasing BMD, increasing age and prior fracture contributed independently to increased fracture risk; in a multivariate model, the relative risk for fracture increased 65% for each SD decrease in BMD (RR=1.65, 95%CI 1.32–2.05), increased 3% for every year of age (RR=1.03, 95%CI 1.01–1.06) and doubled with prevalent fracture (RR=2.01, 95% CI 1.40–2.88). A prevalent fracture increased the risk for fractures such that women with osteopenia and prevalent fracture had the same, if not greater, risk as women with osteoporosis alone.

Fracture rates lower in rural than urban communities : the Geelong Osteoporosis Study

Background: Urban and rural communities differ in the incidence of several diseases including coronary heart disease and some cancers. Lower hip fracture rates among rural than urban populations have been reported but few studies have compared rural and urban fractures at sites other than the hip.

Objective: To compare total and site specific fracture rates among adult residents of rural and urban communities within the same population.

Design and setting: This is a population based study on osteoporosis in Australia. All fractures occurring in adult residents over a two year period were ascertained using radiological reports. The rural and urban areas are in close proximity, with the same medical, hospital, and radiological facilities permitting uniform fracture ascertainment.

Main outcome measures: All fracture rates were age adjusted and sex adjusted to the Australian population according to the 1996 census of the Australian Bureau of Statistics and described as the rate per 10 000 person years. The p values refer to the adjusted rate difference.

Results: The hip fracture rate (incidence per 10 000 person years) was 32% lower (39 v 57, p<0.001), and the total fracture rate 15% lower (160 v 188, p=0.004) among rural than urban residents, respectively. The lower fracture rates in the rural population were also apparent for pelvic fractures.

Conclusion: In the older rural population, lower fracture rates at sites typically associated with osteoporosis suggest environmental factors may have a different impact on bone health in this community. If the national rate of hip fracture could be reduced to that of the rural population, the projected increase in hip fracture number attributable to aging of the population could be prevented.

The exclusion of high trauma fractures may underestimate the prevalence of bone fragility fractures in the community : the Geelong Osteoporosis Study

Fractures associated with severe trauma are generally excluded from estimates of the prevalence of osteoporotic fractures in the community. Because the degree of trauma is difficult to quantitate, low bone mass may contribute to fractures following severe trauma. We ascertained all fractures in a defined population and compared the bone mineral density (BMD) of women who sustained fractures in either 'low' or 'high' trauma events with the BMD of a random sample of women from the same population. BMD was measured by dual-energy X-ray absorptiometry and expressed as a standardized deviation (Z score) adjusted for age. The BMD Z scores (mean ± SEM) were reduced in both the low and high trauma groups, respectively: spine-posterior-anterior (- 0.50 ± 0.05 and -0.21 ± 0.08), spine-lateral (-0.28 ± 0.06 and -0.19 ± 0.10), femoral neck (-0.42 ± 0.04 and -0.26 ± 0.09), Ward's triangle (- 0.44 ± 0.04 and -0.28 ± 0.08), trochanter (-0.44 ± 0.05 and -0.32 ± 0.08), total body (-0.46 ± 0.06 and -0.32 ± 0.08), ultradistal radius (- 0.47 ± 0.05 and -0.42 ± 0.07), and midradius (-0.52 ± 0.06 and -0.33 ± 0.09). Except at the PA spine, the deficits were no smaller in the high trauma group. Compared with the population, the age-adjusted odds ratio for osteoporosis (t-score < -2.5) at one or more scanning sites was 3.1 (95% confidence interval 1.9, 5.0) in the high trauma group and 2.7 (1.9, 3.8) in the low trauma group. The data suggest that the exclusion of high trauma fractures in women over 50 years of age may result in underestimation of the contribution of osteoporosis to fractures in the community. Bone density measurement of women over 50 years of age who sustain fractures may be warranted irrespective of the classification of trauma.

Geelong Osteoporosis Study Health Database

The database contains the following clinical, questionnaire and socio-demographic data suitable for cross-sectional and longitudinal analyses:
-Body composition: dual-energy x-ray absorptiometry (DXA) measures of the lumbar spine (posterior-anterior projection), proximal femur, whole body and forearm (ultradistal forearm and distal 33%)
-Other clinical assessments: body weight, height, arm span, waist and hip circumferences, blood pressure, visual acuity, muscle strength, functional reach test and timed ‘up-&-go’ test.
-Mental health: Major axis psychiatric disorders diagnosed using a Structured Clinical Interview.
-Blood and urine collections: blood and urine collected after an overnight fast.
-Questionnaires: exposure to disease, use of medications and supplements, diet, mobility, physical activity, sleep, sun exposure, falls and fractures, alcohol and tobacco use, reproductive history, family history of fractures and disease, quality of life, pain, anxiety and depression.
-Socio-demographics: Country of birth, ethnicity, marital status, education, housing and employment status, occupation, socioeconomic Index for Areas (SEIFA) scores.

Development and validation of the Diet Quality Tool for use in cardiovascular disease prevention settings

The aim of this study was to develop and evaluate a dietary screening tool for use in a secondary cardiovascular disease (CVD) prevention setting to identify an individual’s overall dietary quality. The Diet Quality Tool (DQT) was validated against a 4-day food diary for 37 individuals with established CVD attending cardiac rehabilitation. Construct validity was demonstrated for % energy from saturated fat (P = 0.002, r = –0.500), dietary fibre (P < 0.001, r = 0.559) and omega-3 fatty acids (P = 0.048, r = 0.327). Criterion validity was established with a significant difference found between mean (95% CI) dietary intakes of fibre (28.2 g, 4.4 to 17.3) and % total energy from saturated fat (10.6%, –4.8 to –0.8) for those with better DQT scores (>60%) versus those with poorer scores (≤60%) when compared with 4-day food diary nutrient values. The usefulness of the DQT was confirmed by both patients (n = 25) and cardiac rehabilitation health professionals (n = 8). The DQT was found to be a valid and useful dietary assessment tool with potential for use in a secondary CVD prevention setting. The tool has the capacity to be used in a wider variety of settings and further refinement of the tool would enable a greater amount of nutrients to be reliably screened.

The role of reducing intakes of saturated fat in the prevention of cardiovascular disease : where does the evidence stand in 2010?

Current dietary recommendations advise reducing the intake of saturated fatty acids (SFAs) to reduce coronary heart disease (CHD) risk, but recent findings question the role of SFAs. This expert panel reviewed the evidence and reached the following conclusions: the evidence from epidemiologic, clinical, and mechanistic studies is consistent in finding that the risk of CHD is reduced when SFAs are replaced with polyunsaturated fatty acids (PUFAs). In populations who consume a Western diet, the replacement of 1% of energy from SFAs with PUFAs lowers LDL cholesterol and is likely to produce a reduction in CHD incidence of >2–3%. No clear benefit of substituting carbohydrates for SFAs has been shown, although there might be a benefit if the carbohydrate is unrefined and has a low glycemic index. Insufficient evidence exists to judge the effect on CHD risk of replacing SFAs with MUFAs. No clear association between SFA intake relative to refined carbohydrates and the risk of insulin resistance and diabetes has been shown. The effect of diet on a single biomarker is insufficient evidence to assess CHD risk. The combination of multiple biomarkers and the use of clinical endpoints could help substantiate the effects on CHD. Furthermore, the effect of particular foods on CHD cannot be predicted solely by their content of total SFAs because individual SFAs may have different cardiovascular effects and major SFA food sources contain other constituents that could influence CHD risk. Research is needed to clarify the role of SFAs compared with specific forms of carbohydrates in CHD risk and to compare specific foods with appropriate alternatives.

Predicting changes in lifestyle and clinical outcomes in preventing diabetes : The Greater Green Triangle Diabetes Prevention Project

Objectives : To analyse how psychosocial determinants of lifestyle changes targeted in the Greater Green Triangle Diabetes Prevention Project conducted in Southeast Australia in 2004–2006 predict changes in dietary behaviour and clinical risk factors.

Methods : A longitudinal pre-test and post-test study design was used. The group program was completed by 237 people at high risk of type 2 diabetes. Associations between changes in the variables were examined by structural equation modelling using a path model in which changes in psychological determinants for lifestyle predicted changes in dietary behaviours (fat and fibre intake), which subsequently predicted changes in waist circumference and other clinical outcomes. Standardised regression weights are presented, with β = ± 0.1 and β = ± 0.3 representing small and medium associations, respectively.

Results : Improvements in coping self-efficacy and planning predicted improvements in fat (β = − 0.15, p < 0.05 and β = − 0.32, p < 0.001, respectively) and fibre intake (β = 0.15, p < 0.05 and β = 0.23, p < 0.001, respectively) which in turn predicted improvements in waist circumference (β = 0.18, p < 0.01 and β = − 0.16, p < 0.05, respectively). Improvements in waist circumference predicted improvements in diastolic blood pressure (β = 0.13, p < 0.05), HDL (β = − 0.16, p < 0.05), triglycerides (β = 0.17, p < 0.01), and fasting glucose (β = 0.15, p < 0.05).

Conclusions : Psychological changes predicted behaviour changes, resulting in 12-month biophysical changes. The findings support the theoretical basis of the interventions.

The importance of long-term follow-up in child and adolescent obesity prevention interventions

Pediatric overweight and obesity continues to be a major public health concern. Once established it is diffi cult to treat; therefore well-designed and evaluated prevention interventions are vitally important. There is considerable evidence to suggest that obesity prevention initiatives can change children ’ s behaviours and weight status over the short- or mediumterm; however, there is far less evidence on which to judge the impact over the longer term. In response to the rise in short- and medium-term obesity prevention studies for children and adolescents over recent years, the Prevention Stream of the Australasian Child and Adolescent Obesity Research Network highlight fi ve points as to why the dearth of obesity prevention studies with long-term follow-up should be urgently addressed. Furthermore, recommendations to strengthen the evidence base and outline key implications for research design in this area and the support required for long-term follow-up studies are detailed.