Association between hyperglycaemia and fracture risk in non-diabetic middle-aged and older Australians : a national, population-based prospective study (AusDiab)

Summary : The association between pre-diabetes and fracture risk remains unclear. In this large cohort of middle-aged and older Australian men and women without diabetes, elevated 2-h plasma glucose and pre-diabetes were associated with a reduced 5-year risk of low trauma and all fractures in women, independently of BMI, fasting insulin and other lifestyle factors.

Introduction : We aimed to (1) examine associations between fasting and 2-h plasma glucose (FPG and 2-h PG), fasting insulin and risk of low trauma and all fractures in non-diabetic adults and (2) compare fracture risk between adults with pre-diabetes (impaired glucose tolerance or impaired fasting glucose) and those with normal glucose tolerance (NGT).

Methods : Six thousand two hundred fifty-five non-diabetic men and women aged ≥40 years with NGT (n = 4,855) and pre-diabetes (n = 1,400) were followed for 5 years in the AusDiab Study. Fractures were self-reported.

Results : Five hundred thirty-nine participants suffered at least one fracture (368 women, 171 men), of which the majority (318) occurred after a low-energy trauma (258 women, 60 men). In women, a 2-h PG ≥7.2 mmol/L (highest quartile) was associated with a decreased risk of low trauma and all fractures independent of age and BMI [OR (95% CI) for low trauma fractures, 0.59 (0.40–0.88)], but also fasting insulin, smoking, physical activity, history of fracture, dietary calcium and alcohol intake or menopausal status. There was no effect of 2-h PG on fracture risk in men [OR (95% CI), 1.39 (0.60–3.26)] or any relationship between fracture risk and quartiles of FPG or insulin in either sex. Compared to women with NGT, those with pre-diabetes had a reduced risk of fracture [OR (95% CI) for all fractures, 0.70 (0.52–0.95); for low trauma fractures, 0.75 (0.53–1.05)].

Conclusion : Elevated 2-h PG levels and pre-diabetes were inversely associated with low trauma and/or all fractures in non-diabetic women, independent of BMI and fasting insulin levels.

Which aspects of socio-economic status are related to health in mid-aged and older women?

A population-based study was conducted to validate gender- and age-specific indexes of socio-economic status (SES) and to investigate the associations between these indexes and a range of health outcomes in 2 age cohorts of women. Data from 11,637 women aged 45 to 50 and 9,510 women aged 70 to 75 were analyzed. Confirmatory factor analysis produced four domains of SES among the mid-aged cohort (employment, family unit, education, and migration) and four domains among the older cohort (family unit, income, education, and migration). Overall, the results supported the factor structures derived from another population-based study (Australian Bureau of Statistics, 1995), reinforcing the argument that SES domains differ across age groups. In general, the findings also supported the hypotheses that women with low SES would have poorer health outcomes than higher SES women, and that the magnitude of these effects would differ according to the specific SES domain and by age group, with fewer and smaller differences observed among older women. The main exception was that in the older cohort, the education domain was significantly associated with specific health conditions. Results suggest that relations between SES and health are highly complex and vary by age, SES domain, and the health outcome under study.

Effects of resistance exercise and fortified milk on skeletal muscle mass, muscle size, and functional performance in middle-aged and older men: an 18-mo randomized controlled trial

Limited data have suggested that the consumption of fluid milk after resistance training (RT) may promote skeletal muscle hypertrophy. The aim of this study was to assess whether a milk-based nutritional supplement could enhance the effects of RT on muscle mass, size, strength, and function in middle-aged and older men. This was an 18-mo factorial design (randomized control trial) in which 180 healthy men aged 50–79 yr were allocated to the following groups: 1) exercise + fortified milk, 2) exercise, 3) fortified milk, or 4) control. Exercise consisted of progressive RT with weight-bearing impact exercise. Men assigned to the fortified milk consumed 400 ml/day of low-fat milk, providing an additional 836 kJ, 1000 mg calcium, 800 IU vitamin D3, and 13.2 g protein per day. Total body lean mass (LM) and fat mass (FM) (dual-energy X-ray absorptiometry), midfemur muscle cross-sectional area (CSA) (quantitative computed tomography), muscle strength, and physical function were assessed. After 18 mo, there was no significant exercise by fortified milk interaction for total body LM, muscle CSA, or any functional measure. However, main effect analyses revealed that exercise significantly improved muscle strength (∼20–52%, P < 0.001), LM (0.6 kg, P < 0.05), FM (−1.1 kg, P < 0.001), muscle CSA (1.8%, P < 0.001), and gait speed (11%, P < 0.05) relative to no exercise. There were no effects of the fortified milk on muscle size, strength, or function. In conclusion, the daily consumption of low-fat fortified milk does not enhance the effects of RT on skeletal muscle size, strength, or function in healthy middle-aged and older men with adequate energy and nutrient intakes.

Effects of lifetime loading history on cortical bone density and its distribution in middle-aged and older men

We have reported previously that long-term participation of weight-bearing exercise is associated with increased QCT-derived cortical bone size and strength in middle-aged and older men, but not whole bone cortical volumetric BMD. However, since bone remodeling and the distribution of loading-induced strains within cortical bone are non-uniform, the aim of this study was to examine the effects of lifetime loading history on cortical bone mass distribution and bone shape in healthy community dwelling middle-aged and older men. We used QCT to assess mid-femur and mid-tibia angular bone mass distribution around its center (polar distribution), the bone density distribution through the cortex (radial distribution), and the ratio between the maximum and minimum moments of inertia (I_max/I_min ratio) in 281 men aged 50 to 79 years. Current (> 50 years) and past (13–50 years) sport and leisure time activity was assessed by questionnaire to calculate an osteogenic index (OI) during adolescence and adulthood. All men were then categorized into a high (H) or low/non impact (L) group according to their OI scores in each period. Three contrasting groups were then formed to reflect weight-bearing impact categories during adolescence and then adulthood: H–H, H–L and L–L. For polar bone mass distribution, bone deposition in the anterolateral, medial and posterior cortices were 6–10% greater at the mid-femur and 9–24% greater at mid-tibia in men in the highest compared to lowest tertile of lifetime loading (p < 0.01– < 0.001). When comparing the influence of contrasting loading history during adolescence and adulthood, there was a graded response between the groups in the distribution of bone mass at the anterior-lateral and posterior regions of the mid-tibia (H–H > H–L > L–L). For radial bone density distribution, there were no statistically significant effects of loading at the mid-femur, but a greater lifetime OI was associated with a non-significant 10–15% greater bone density near the endocortical region of the mid-tibia. In conclusion, a greater lifetime loading history was associated with region-specific adaptations in cortical bone density.

Mid-femoral and mid-tibial muscle cross-sectional area as predictors of tibial bone strength in middle-aged and older men

While it is widely acknowledged that bones adapt to the site-specific prevalent loading environment, reasonable ways to estimate skeletal loads are not necessarily available. For long bone shafts, muscles acting to bend the bone may provide a more appropriate surrogate of the loading than muscles expected to cause compressive loads. Thus, the aim of this study was to investigate whether mid-thigh muscle cross-sectional area (CSA) was a better predictor of tibial mid-shaft bone strength than mid-tibia muscle CSA in middle aged and older men. 181 Caucasian men aged 50–79 years (mean±SD; 61±7 years) participated in this study. Mid-femoral and mid-tibial bone traits cortical area , density weighted polar moment of area and muscle CSA [cm²] were assessed with computed tomography. Tibial bone traits were positively associated with both the mid-femur (r=0.44 to 0.46, P<0.001) and the mid-tibia muscle CSA (r=0.35 to 0.37, P<0.001). Multivariate regression analysis, adjusting for age, weight, physical activity and femoral length, indicated that mid-femur muscle CSA predicted tibial mid-shaft bone strength indices better thn mid-tibia muscle CSA. In conclusion, the association between a given skeletal site and functionally adjacent muscles may provide a meaningful probe of the site-specific effect of loading on bone.

Relationship of the perceived social and physical environment with mental health-related quality of life in middle-aged and older adults: mediating effects of physical activity

BACKGROUND: Mental health conditions are among the leading non-fatal diseases in middle-aged and older adults in Australia. Proximal and distal social environmental factors and physical environmental factors have been associated with mental health, but the underlying mechanisms explaining these associations remain unclear. The study objective was to examine the contribution of different types of physical activity in mediating the relationship of social and physical environmental factors with mental health-related quality of life in middle-aged and older adults. METHODS: Baseline data from the Wellbeing, Eating and Exercise for a Long Life (WELL) study were used. WELL is a prospective cohort study, conducted in Victoria, Australia. Baseline data collection took place in 2010. In total, 3,965 middle-aged and older adults (55-65 years, 47.4% males) completed the SF-36 Health Survey, the International Physical Activity Questionnaire, and a questionnaire on socio-demographic, social and physical environmental attributes. Mediation analyses were conducted using the MacKinnon product-of-coefficients test. RESULTS: Personal safety, the neighbourhood physical activity environment, social support for physical activity from family or friends, and neighbourhood social cohesion were positively associated with mental health-related quality of life. Active transportation and leisure-time physical activity mediated 32.9% of the association between social support for physical activity from family or friends and mental health-related quality of life. These physical activity behaviours also mediated 11.0%, 3.4% and 2.3% respectively, of the relationship between the neighbourhood physical activity environment, personal safety and neighbourhood social cohesion and mental health-related quality of life. CONCLUSIONS: If these results are replicated in future longitudinal studies, tailored interventions to improve mental health-related quality of life in middle-aged and older adults should use a combined strategy, focusing on increasing physical activity as well as social and physical environmental attributes.

Gender specific age-related changes in bone density, muscle strength and functional performance in the elderly: a-10 year prospective population-based study

Background: 

From recruitment to consent : what makes doctors want to participate in the review of lifescripts

Aims & rationale/Objectives : The Australian Government wants the Lifescripts resources to be utilised by general practices. Therefore a national review has been commissioned.The aim of this presentation is to identify characteristics, barriers and enablers associated with consenting and non-consenting general practices within two Victorian general practice networks.
Methods : Recruitment of general practice staff consisted of three phases: promotion, communication and practice visits. Recruitment occurred from Sept to November 2007. Data was collected via face to face interviews.
Principal findings : Prior to the consenting phase 17 practices expressed interest in participation. At the consent phase, 10 general practices (7% response), 17 GPs (3% response), and three practice nurses (2.5% response) agreed to participate.Consenting practices had more: principal GPs involved in the recruitment process; greater intention to implement Lifescripts around MBS numbers; more experience with change management strategies, consulting health professionals, and defined their practice population(s) as middle aged and older.Non-consenting practices identified the following barriers: lack of support from principal general practitioners or owners; lack of capacity to incorporate Lifescripts into existing computer software; lack of financial incentive; heavy work loads and poor patient response to 45 health check.est
Implications : Inform general practices of a resource to assist them to detect and prevent chronic disease, and enable early intervention strategies. The benefit of this presentation is that it identifies the importance of determining barriers and enabling factors when implementing a lifestyle based service program at general practice level.
Presentation type : Poster

Major dietary patterns of young and middle aged women : results from a prospective Australian cohort study

Objective: The aim of this study was to assess the major dietary patterns of two age cohorts of women, to determine to the extent to which the dietary patterns differ between the cohorts and to assess whether they vary according to sociodemographic and behavioural characteristics and patterns of nutrient intake.

Method: Dietary intake was assessed using an 80-item food frequency questionnaire for women aged 50–55 years (n=10 150; ‘middle age’) in 2001 and aged 25–30 years (n=7371; ‘young’) in 2003, from the Australian Longitudinal Study on Women's Health. Factor analysis using principal component extraction was used to identify dietary patterns, and a pattern score was calculated from the consumption of the food items identified with each dietary pattern. Associations between the dietary pattern scores and sociodemographic and behavioural characteristics and nutrient intakes were investigated using regression analysis.

Results: Six dietary patterns were identified and were labelled: cooked vegetables; fruit; Mediterranean-style; processed meat, meat and takeaway; reduced fat dairy; and high-fat and sugar foods. Regression analysis revealed that healthier dietary patterns were significantly associated with other favourable health-related behaviours, higher socioeconomic status and living in urban areas (P-values <0.05).

Conclusions: In spite of differences in the level of consumption of individual food items, the similarity in dietary patterns across two generations of women suggests that policies and interventions to improve diet should focus on social and economic factors and general health-related behaviour rather than different age groups.

Akt, AS160, metabolic risk factors and aerobic fitness in middle-aged women

This study investigated the association between the basal (rest) insulin-signaling proteins, Akt, and the Akt substrate AS160, metabolic risk factors, inflammatory markers and aerobic fitness, in middle-aged women with varying numbers of metabolic risk factors for type 2 diabetes. Methods: Sixteen women (n=16) aged 51.3±5.1 (mean ±SD) years provided muscle biopsies and blood samples at rest. In addition, anthropometric characteristics and aerobic power were assessed and the number of metabolic risk factors for each participant was determined (IDF criteria). Results: The mean number of metabolic risk factors was 1.6±1.2. Total Akt was negatively correlated with IL-1β (r = -0.45, p = 0.046), IL-6 (r = -0.44, p = 0.052) and TNF-α (r = -0.51, p = 0.025). Phosphorylated AS160 was positively correlated with HDL (r = 0.58, p= 0.024) and aerobic fitness (r = 0.51, p=0.047). Furthermore, a multiple regression analysis revealed that both HDL (t=2.5, p=0.032) and VO_2peak (t=2.4, p=0.037) were better predictor for phosphorylated AS160 than TNF-α or IL-6 (p>0.05). Conclusions: Elevated inflammatory markers and increased metabolic risk factors may inhibit insulin-signaling protein phosphorylation in middle-aged women, thereby increasing insulin resistance under basal conditions. Furthermore, higher HDL and fitness levels are associated with an increase AS160 phosphorylation, which may in turn reduce insulin resistance.

Resistance and reconstruction: Older women talk about childhood sexual abuse

Research which explores the experiences of women, who have experienced childhood sexual abuse is, in the main, focused on young and middle aged women. The perspectives of older women is often absent or hidden in the literature. This study explores the experiences of 16 Australian women aged 57 years and older who have experienced childhood sexual abuse. It aims to privilege their views and highlight their particular contexts in order to redress professional assumptions regarding the notions of recovery. Additionally, in discussing their experiences, the women contribute to insights regarding the patterns of inequality which are produced as a result of dominant discourses that promote ageist and sexist prescriptions in the construction of the self. These insights demonstrate how the women have resisted a range of oppressive patterns in their everyday lives. The study follows a feminist research framework and aims to contribute to the fields of social work practice and critical feminist gerontology.

Increasing BMI was associated with increasing risk for overall cancer incidence and mortality in middle-aged women

Question: In middle-aged women, what is the association between body mass index (BMI) and cancer incidence and mortality?METHODSDesign: Prospective cohort study with mean follow-up of 5.4 years for cancer incidence and 7.0 years for cancer mortality.Setting: Population-based study in England and Scotland, United Kingdom.Patients: 1 222 630 women 55 to 64 years of age (mean 56 y) who had no history of cancer at baseline.Risk factors: BMI at baseline, divided into 5 categories (< 22.5, 22.5 to 24.9, 25.0 to 27.4, 27.5 to 29.9, and ≥ 30 kg/m2).Outcomes: Cancer incidence and mortality, overall and for 17 specific types of cancer, identified through linkage with the National Health Service central registers.Main results: Increasing BMI was associated with increasing risks for all cancers, endometrial cancer, esophageal adenocarcinoma, kidney cancer, leukemia, postmenopausal breast cancer, multiple myeloma, pancreatic cancer, non-Hodgkin lymphoma, and ovarian cancer; and with decreasing risks for esophageal squamous cell carcinoma, lung cancer, and premenopausal breast cancer (Table). Risks for stomach, colorectal, cervical, bladder, and brain cancer and malignant melanoma did not vary by BMI. Patterns for cancer mortality were similar to those for cancer incidence: Relative risk for death from any type of cancer was 1.06 (95% CI 1.02 to 1.10) per 10-unit increase in BMI. In postmenopausal women, the estimated proportion of cancer attributable to being overweight or obese (BMI ≥ 25 kg/m2) was 5% for all cancers and about 50% for endometrial cancer and esophageal adenocarcinoma.Conclusions: In middle-aged women, increasing body mass index was associated with increasing risk for cancer incidence and mortality overall. High body mass index increased risk for some types of cancer but reduced risk for other types.