Effects of a Multi-component, Resistance-Based Exercise Program Combined with Additional Lean Red Meat on Health-Related Quality of Life in Older Adults: Secondary Analysis of a 6-Month Randomized Controlled Trial.

OBJECTIVES: To assess whether consumption of lean red meat on three exercise training days per week can promote greater improvements than exercise alone in health-related quality of life (HR-QoL) in community-dwelling older adults. DESIGN: This study is a secondary analysis from a 6 month, two-arm, parallel randomized controlled trial conducted in 2014 and 2015. SETTING: Community-dwelling older adults living in metropolitan Melbourne, Australia. PARTICIPANTS: One hundred and fifty-four men and women aged ≥65 years. INTERVENTION: All participants were enrolled in a multi-component, resistance-based exercise program (3 d/week) and randomly allocated to either a group asked to consume lean red meat (2x80g cooked servings/day) on each of the three training days (Ex+Meat, n=77) or a control group asked to consume one serving of carbohydrates (1/2 cup rice/pasta or 1 medium potato; Ex+C, n=77). MEASUREMENTS: HR-QoL was assessed using the Short-Form (SF)-36 health survey. RESULTS: Overall 62% of the participants were female, the mean age was 70.7 years (range 65 to 84 years), approximately 67% of participants were classified as either overweight or obese, and the average number of chronic conditions was two. A total of 145 participants (94%) completed the study. Mean baseline HR-QoL scores were comparable to the mean for the Australian population [Global HR-QoL (mean ± SD): Ex+Meat, 49.99 ± 6.57; Ex+C, 50.49 ± 5.27]. General Linear Mixed Models examining within and between group changes over time revealed that after 6 months, there were no within-group changes in either Ex+Meat or Ex+C nor any between-group differences for any measure of HR-QoL, with the exception that the mental health subscale improved in Ex+C versus Ex+Meat [net difference for change, -2.32 (95% CI), -4.73, 0.09, P=0.048] after adjusting for relevant covariates and the physical function subscale improved in Ex+Meat relative to baseline [mean change (95% CI), 1.88 (0.37, 3.39), P=0.011]. CONCLUSION: A multi-component resistance-based training program performed with and without the provision of lean red meat in line with current Australian dietary guidelines on each of the three training days, did not improve HR-QoL in healthy community-dwelling older adults.

A qualitative investigation of school age children, their parents and school staff on their participation in the Digital Education to LImit Salt in the Home (DELISH) program.

This study explored the views of participants who completed a 5-week, online, interactive, family-based, salt reduction education program (Digital Education to LImit Salt in the Home). A secondary aim was to explore the views of school staff on the delivery of food and nutrition education in schools. Children aged 7-10 years, their parents and principals/teachers from participating schools located in Victoria, Australia, completed a semi-structured evaluation interview. Audio-recordings of interviews were transcribed verbatim and analysed using NVivo. Twenty-eight interviews (13 children; 11 parents; 4 school staff) were included. Thematic analysis revealed that the program was well received by all groups. Children reported that the interactivity of the education sessions helped them to learn. Parents thought the program was interesting and important, and reported learning skills to reduce salt in the family diet. School staff supported the delivery of nutrition education in schools but indicated difficulties in sourcing well-packed nutrition resources aligned with the curriculum. It appears that there is support from parents and teachers in the delivery of innovative, engaging, nutrition education in schools, however such programs need to be of high quality, aligned with the school curriculum and readily available for incorporation within the school's teaching program.

Association of sitting time and breaks in sitting with muscle mass, strength, function, and inflammation in community-dwelling older adults.

The mechanisms through which excessive sitting time impacts health are important to understand. This study found that each hour of sitting per day was not associated with physical function, although associations with poor body composition were observed. Reducing sitting time for improved weight management in older adults needs further exploration. INTRODUCTION: To examine the association of sitting time and breaks in sitting time with muscle mass, strength, function, and inflammation in older Australians. METHODS: Data from the thigh-worn activPAL3™ monitor (7-day continuous wear) was used to derive time spent sitting (hours) and total number of sit-stand transitions per day. Body composition (dual energy X-ray absorptiometry), lower-body muscle strength, function (timed up-and-go [TUG], 4-m gait speed, four square step test, 30-second sit-to-stand), and serum inflammatory markers (interleukin-[IL-6], IL-8, IL-10, tumor necrosis factor-alpha [TNF-α], and adiponectin) were measured. Multiple regression analyses, adjusted for age, sex, ethnicity, education, employment status, marital status, number of prescription medications, smoking status, vitamin D, and stepping time, were used to assess the associations. RESULTS: Data from 123 community-dwelling older adults (aged 65-84 years, 63% female) were used. Total daily sitting time was associated with lower percentage lean mass (ß [95%CI], - 1.70% [- 2.30, - 1.10]) and higher total body fat mass (2.92 kg [1.94, 3.30]). More frequent breaks in sitting time were associated with a 45% reduced risk of having pre-sarcopenia (OR = 0.55; 95% CI 0.34, 0.91; model 1), defined as appendicular lean mass divided by BMI. No significant associations were observed for sitting time or breaks in sitting with measures of muscle strength, function, or inflammation. CONCLUSION: In older community-dwelling adults, greater sitting time was associated with a lower percentage lean mass, while more frequent breaks in sitting time were associated with lower odds of having pre-sarcopenia. This suggests that reducing sedentary time and introducing frequent breaks in sedentary time may be beneficial for improving body composition in healthy older adults.

The Impact of Dietary Factors on Indices of Chronic Disease in Older People: A Systematic Review.

OBJECTIVES: There has been little evaluation of the evidence relating dietary factors to functional capacity in older adults. The aims were to i) conduct a systematic review of studies assessing dietary factors in relation to six key functional indicators which impact on quality of life in adults ≥65 yrs: non-fatal cardiovascular events, cognition, mental health, falls and fractures, physical health (muscle mass, strength) and frailty; and ii) assess if there was sufficient evidence to devise food-based dietary recommendations. DESIGN: Systematic review. PARTICIPANTS: Cross-sectional and prospective cohort studies were included together with intervention studies that evaluated food/drink interventions (excluding supplements). Evidence base statements were determined according to the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) levels of evidence criteria (Grades (A-excellent; B-good; C-satisfactory; D-poor). RESULTS: There was good evidence that the Mediterranean type diet (MD) reduced the risk of non-fatal cardiovascular events (Grade B) and reduced cognitive decline (Grade B). There was some evidence indicating that a MD decreases the likelihood of frailty (Grade C), consistent but weaker evidence that ≥3 servings/d of vegetables is associated with reduced cognitive decline (Grade D), a modest increase in protein may be associated with improved cognition (Grade C) and decreased frailty (Grade C), and that protein plus resistance exercise training in frail elderly may enhance physical strength (Grade C). CONCLUSION: It is recommended that older adults adopt the characteristics of a Mediterranean type diet such as including olive oil and eating ≥3 servings/d of vegetables to reduce their risk of chronic disease, impaired cognition and frailty. Consumption of dietary protein above the current dietary requirements would be recommended to reduce risk of frailty and impaired cognition. A modest increase in dietary protein when combined with resistance exercise would be recommended to help maintain muscle mass and strength and to enhance functional capacity.

The Influence of Age the BMI and All-Cause Mortality Association: A Meta-Analysis.

OBJECTIVES: To assess BMI range with the lowest mortality for those aged <65 years and those ≥65 years, utilising cohort studies that spanned the entire adult age range. DESIGN: A two-stage random effects meta-analysis of studies that reported mortality in cohorts both ≥65 years and <65 years. Setting / Participants: Community living adults aged ≥65 and <65 years. RESULTS: Eight studies were included with a total of 370 416 subjects (306 340 aged <65 years; 64 076 ≥65 years). In the older age group, mortality risk increased at BMIs lower than 22 (BMI range 21.0-21.9: hazard ratio (HR) (95% confidence interval (CI)): 1.05 (1.03, 1.07)), which was not seen in younger adults. In the younger group, mortality increased from BMI range 28.0-28.9 (HR (95% CI): 1.13 (1.00, 1.29)), but mortality did not tend to increase significantly in the older group at BMIs above 23. CONCLUSION: The recommended healthy weight range is appropriate for younger and middle aged adults but a higher BMI range should be recommended for older adults based on mortality.

A novel processed food classification system applied to Australian food composition databases.

BACKGROUND: The extent of food processing can affect the nutritional quality of foodstuffs. Categorising foods by the level of processing emphasises the differences in nutritional quality between foods within the same food group and is likely useful for determining dietary processed food consumption. The present study aimed to categorise foods within Australian food composition databases according to the level of food processing using a processed food classification system, as well as assess the variation in the levels of processing within food groups. METHODS: A processed foods classification system was applied to food and beverage items contained within Australian Food and Nutrient (AUSNUT) 2007 (n = 3874) and AUSNUT 2011-13 (n = 5740). The proportion of Minimally Processed (MP), Processed Culinary Ingredients (PCI) Processed (P) and Ultra Processed (ULP) by AUSNUT food group and the overall proportion of the four processed food categories across AUSNUT 2007 and AUSNUT 2011-13 were calculated. RESULTS: Across the food composition databases, the overall proportions of foods classified as MP, PCI, P and ULP were 27%, 3%, 26% and 44% for AUSNUT 2007 and 38%, 2%, 24% and 36% for AUSNUT 2011-13. Although there was wide variation in the classifications of food processing within the food groups, approximately one-third of foodstuffs were classified as ULP food items across both the 2007 and 2011-13 AUSNUT databases. CONCLUSIONS: This Australian processed food classification system will allow researchers to easily quantify the contribution of processed foods within the Australian food supply to assist in assessing the nutritional quality of the dietary intake of population groups.

Australian general practitioners' views regarding providing nutrition care: results of a national survey.

BACKGROUND: The prevalence of chronic disease is considerable, and dietary behaviours influence the progression of many chronic diseases. Practice guidelines recommend that general practitioners (GPs) promote healthy dietary behaviours in relevant consultations with patients in order to improve health outcomes at a population level. OBJECTIVE: To describe GPs' perceived interest, confidence and barriers to support patients to have a healthy diet. METHOD: A 24-item online and written survey was distributed in a national weekly newsletter to GPs in Australia. Results were descriptively analysed and investigated for associations with GPs' demographic characteristics. RESULTS: A total of 322 GPs responded to the survey. Nearly all (n = 295, 91.6%) were interested in supporting patients to eat well, and most (n = 231, 71.7%) reported moderately high confidence for providing nutrition care with clear public health messages for conditions, such as cardiovascular disease. Many GPs (n = 170, 52.8%) cited lack of time as the biggest barrier to providing nutrition care, and the overwhelming majority (n = 289, 89.8%) were interested in receiving additional education and training to enhance their nutrition knowledge and skills. DISCUSSION: Many GPs are interested in nutrition and would benefit from educational programmes that improve their competence to provide nutrition care. Professional development opportunities should focus on the identification of nutritional risk and the promotion of healthy dietary behaviours within the time constraints of a standard consultation.

Physiological responses to psychological stress: importance of adiposity in men aged 50-70 years.

We tested the hypothesis that overweight/obese men aged 50-70 years will have a greater salivary cortisol, salivary alpha amylase and heart rate (HR) responses to psychological stress compared with age matched lean men. Lean (BMI=20-25 kg/m(2); n=19) and overweight/obese (BMI=27-35 kg/m(2); n=17) men (50-70 years) were subjected to a well-characterised psychological stress (Trier Social Stress Test, TSST) at 1500 h. Concentrations of cortisol and alpha amylase were measured in saliva samples collected every 7-15 min from 1400 to 1700 h. HR was recorded using electrocardiogram. Body weight, BMI, percentage body fat, resting systolic and diastolic blood pressure and mean arterial pressure were significantly higher (P<0.05) in overweight/obese men compared with lean men. Both groups responded to the TSST with a substantial elevation in salivary cortisol (372%), salivary alpha amylase (123%) and HR (22%). These responses did not differ significantly between the groups (time×treatment interaction for salivary cortisol, salivary alpha amylase and HR; P=0.187, P=0.288, P=0.550, respectively). There were no significant differences between the groups for pretreatment values, peak height, difference between pretreatment values and peak height (reactivity) or area under the curve for salivary cortisol, salivary alpha amylase or HR (P>0.05 for all). The results showed that, for men with a moderate level of overweight/obesity who were otherwise healthy, the response of salivary cortisol, salivary alpha amylase and HR to acute psychological stress was not impaired.

Vitamin D status and musculoskeletal health in adolescent male ballet dancers a pilot study.

Adequate vitamin D levels during growth are critical to ensuring optimal bone development. Vitamin D synthesis requires sun exposure; thus, athletes engaged in indoor activities such as ballet dancing may be at relatively high risk of vitamin D insufficiency. The objective of this study was to investigate the prevalence of low vitamin D levels in young male ballet dancers and its impact on musculoskeletal health. Eighteen male ballet dancers, aged 10 to 19 years and training for at least 6 hours per week, were recruited from the Australian Ballet School, Melbourne, Australia. Serum 25(OH)D and intact PTH were measured in winter (July) from a non-fasting blood sample. Pubertal stage was determined using self-assessed Tanner criteria. Body composition and areal bone mineral density (aBMD) at the whole body and lumbar spine were measured using dual-energy x-ray absorptiometry (DXA). Injury history and physical activity levels were assessed by questionnaire. Blood samples were obtained from 16 participants. Serum 25(OH)D levels ranged from 20.8 to 94.3 nmol/L, with a group mean of 50.5 nmol/L. Two participants (12.5%) showed vitamin D deficiency [serum 25(OH)D level < 25 nmol/L], seven dancers (44%) had vitamin D insufficiency (25 to 50 nmol/L), and the remaining seven dancers (44%) had normal levels (> 50 nmol/L). No relationship was found between vitamin D status, PTH levels, body composition, and aBMD. The most commonly reported injuries were muscle tears and back pain. The average number of injuries reported by each dancer was 1.9 ± 0.4 (range: 0 to 5). There was no difference in the frequency of reported injuries between subjects with vitamin D deficiency or insufficiency (2.1 ± 0.6 injuries) and those with normal vitamin D levels (1.4 ± 0.6 injuries). This pilot study showed that more than half of highly-trained young male ballet dancers presented with low levels of vitamin D in winter. Further investigations in larger samples of adolescent athletes are needed to determine if this could negatively impact bone growth and place them at higher risk for musculoskeletal injuries.

Depression, nutritional risk and eating behaviour in older caregivers.

OBJECTIVE: This study investigated the relationship between depression, nutritional risk and dietary intake in a population of older caregivers. DESIGN: Mailed questionnaire with sub group participating in a home-based interview. PARTICIPANTS AND SETTING: Seventy-six community dwelling caregivers aged 50 y or over from Victoria, Australia. MEASUREMENTS: Questionnaires provided information on weight, height, hours of care, depressive symptoms, nutritional risk and appetite. The home-based interview assessed dietary intake and shopping, cooking and meal consumption habits. RESULTS: The sample had a mean +/- SD age of 70.3 +/- 12.8 y, BMI of 27.2 +/- 4.8 kg/m2 and the time spent caring was 101.8 +/- 68.1 h/wk. Overall, 32% of caregivers had depressive symptoms, 21% were at risk of malnutrition and 21% reported their appetite was fair/bad/very bad. Caregivers with depressive symptoms (32%) compared to those with no depressive symptoms (53%) had a poorer appetite (p < 0.05). Of the 20 caregivers who participated in the home interview, 25% reported they ate their meals alone. CONCLUSION: A significant proportion of community dwelling older caregivers had depressive symptoms, were at risk of malnutrition and had poor appetites, although the majority were overweight or obese.

Long-term effect of calcium-vitamin D(3) fortified milk on blood pressure and serum lipid concentrations in healthy older men.

BACKGROUND/OBJECTIVES: Some epidemiological and clinical studies have shown that increased dairy consumption or calcium and/or vitamin D supplementation can have a beneficial effect on blood pressure, and lipid and lipoprotein concentrations. The aim of this study was to assess the long-term effects of calcium-vitamin D(3) fortified milk on blood pressure and lipid-lipoprotein concentrations in community-dwelling older men. SUBJECTS/METHODS: This is a substudy of a 2-year randomized controlled trial in which 167 men aged >50 years were assigned to receive either 400 ml per day of reduced fat (approximately 1%) milk fortified with approximately 1000 mg of calcium and 800 IU of vitamin D(3) or to a control group receiving no additional fortified milk. Weight, blood pressure, lipid and lipoprotein concentrations were measured every 6 months. Participants on lipid-lowering (n=32) or antihypertensive medication (n=39) were included, but those who commenced, increased or decreased their medication throughout the intervention were excluded (n=27). RESULTS: In the 140 men included in this study (milk, n=73; control, n=67), there were no significant effects of the calcium-vitamin D(3) fortified milk on weight, systolic or diastolic blood pressure, total cholesterol, high-density lipoprotein or low-density lipoprotein cholesterol or triglyceride concentrations at any time throughout the intervention. Similar results were observed after excluding men taking antihypertensive or lipid-lowering medication or limiting the analysis to those with baseline calcium intakes <1000 mg per day and/or with hypovitaminosis D (25(OH)D <75 nmol/l). CONCLUSIONS: Supplementation with reduced-fat calcium-vitamin D(3) fortified milk did not have a beneficial (nor detrimental) effect on blood pressure, lipid or lipoprotein concentrations in healthy community-dwelling older men.

Effects of a multi-component exercise program and calcium-vitamin-D3-fortified milk on bone mineral density in older men: a randomised controlled trial.

SUMMARY: We examined the independent and combined effects of a multi-component exercise program and calcium-vitamin-D(3)-fortified milk on bone mineral density (BMD) in older men. Exercise resulted in a 1.8% net gain in femoral neck BMD, but additional calcium-vitamin D(3) did not enhance the response in this group of older well-nourished men. INTRODUCTION: This 12-month randomised controlled trial assessed whether calcium-vitamin-D(3)-fortified milk could enhance the effects of a multi-component exercise program on BMD in older men. METHODS: Men (n = 180) aged 50-79 years were randomised into: (1) exercise + fortified milk; (2) exercise; (3) fortified milk; or (4) controls. Exercise consisted of high intensity progressive resistance training with weight-bearing impact exercise. Men assigned to fortified milk consumed 400 mL/day of low fat milk providing an additional 1,000 mg/day calcium and 800 IU/day vitamin D(3). Femoral neck (FN), total hip, lumbar spine and trochanter BMD and body composition (DXA), muscle strength 25-hydroxyvitamin D and parathyroid hormone (PTH) were assessed. RESULTS: There were no exercise-by-fortified milk interactions at any skeletal site. Exercise resulted in a 1.8% net gain in FN BMD relative to no-exercise (p < 0.001); lean mass (0.6 kg, p < 0.05) and muscle strength (20-52%, p < 0.001) also increased in response to exercise. For lumbar spine BMD, there was a net 1.4-1.5% increase in all treatment groups relative to controls (all p < 0.01). There were no main effects of fortified milk at any skeletal site. CONCLUSION: A multi-component community-based exercise program was effective for increasing FN BMD in older men, but additional calcium-vitamin D(3) did not enhance the osteogenic response.

Multivitamin supplementation improves nutritional status and bone quality in aged care residents.

OBJECTIVES: To assess the effectiveness of a multivitamin (MV) tablet on nutritional status, quantitative heel ultrasound (QUS), mobility, muscle strength and falls. The design comprised two groups matched on mobility levels, randomized to receive a daily MV or placebo (P) tablet for 6 months. The setting was an Australian residential care facility. SUBJECTS: A total of 92 aged care residents. Serum micronutrients, body weight, QUS, rate of falls, hand grip strength, and the timed up and go test were assessed at baseline and 6 months. RESULTS: A total of 49 participants consumed a MV and 43, a matched P for 6 months. There was a greater increase in the MV vs P group for serum 25(OH)D (mean difference+/-standard error, 33.4+/-2.6 nmol l(-1)), folate (13.4+/-2.8 nmol l(-1)), and vitamin B12 (178.0+/-40.3 pmol l(-1)) (all P<0.001). Adequate 25(OH)D concentrations (> or =50 nmol l(-1)) were found among 77% of participants in the MV group vs 10% taking P (P<0.001). Adjusting for baseline levels, the increase in QUS was greater in the MV vs P group (3.0+/-2.0 dB MHz(-1) vs -2.9+/-2.1 dB MHz(-1), respectively, P=0.041). There was a trend towards a 63% lower mean number of falls in the MV vs P group (0.3+/-0.1 falls vs 0.8+/-0.3 falls, P=0.078). CONCLUSIONS: MV supplementation raised serum vitamin B12 and folate concentrations and increased serum 25(OH)D, which was accompanied by an apparent positive effect on bone density. We also found a trend towards a reduction in falls and this could contribute to a reduction in fractures.

Increased consumption of fruit and vegetables is related to a reduced risk of coronary heart disease: meta-analysis of cohort studies.

Increased consumption of fruit and vegetables has been shown to be associated with a reduced risk of coronary heart disease (CHD) in many epidemiological studies, however, the extent of the association is uncertain. We quantitatively assessed the relation between fruit and vegetable intake and incidence of CHD by carrying out a meta-analysis of cohort studies. Studies were included if they reported relative risks (RRs) and corresponding 95% confidence interval (CI) of CHD with respect to frequency of fruit and vegetable intake. Twelve studies, consisting of 13 independent cohorts, met the inclusion criteria. There were 278,459 individuals (9143 CHD events) with a median follow-up of 11 years. Compared with individuals who had less than 3 servings/day of fruit and vegetables, the pooled RR of CHD was 0.93 (95% CI: 0.86-1.00, P=0.06) for those with 3-5 servings/day and 0.83 (0.77-0.89, P<0.0001) for those with more than 5 servings/day. Subgroup analyses showed that both fruits and vegetables had a significant protective effect on CHD. Our meta-analysis of prospective cohort studies demonstrates that increased consumption of fruit and vegetables from less than 3 to more than 5 servings/day is related to a 17% reduction in CHD risk, whereas increased intake to 3-5 servings/day is associated with a smaller and borderline significant reduction in CHD risk. These results provide strong support for the recommendations to consume more than 5 servings/day of fruit and vegetables.

Nutrient intake and plate waste from an Australian residential care facility.

OBJECTIVE: To determine the plate waste, energy and selected-nutrient intake, from elderly residents living in a high-level care (HLC) and low-level care (LLC) facility. DESIGN: Three, single, whole day assessments of plate waste, energy, and selected nutrients, using a visual rating plate waste scale. SETTING: Long-term residential care establishment. SUBJECTS: One hundred and sixty-nine (93 HLC and 76 LLC) individual daily intakes. MAIN FINDINGS: The mean energy wasted throughout the whole day was 17%. The energy wasted from main meals (16%) was significantly less than the energy wasted at mid-meals (22%, P=0.049). The lowest mean energy wastage occurred at breakfast (8%) compared to lunch (22%) and dinner (25%, P<0.001). The mean (s.d.) daily energy served and consumed was 8.1 (2.0) and 6.6 (2.2) MJ, respectively. There was no difference in energy served or consumed between HLC and LLC residents. On the observation day, 60% of residents consumed less than their estimated energy requirement. The mean calcium intake was 796 (346) mg, and the median (inter-quartile range) vitamin D intake was 1.78 (2.05) microg. CONCLUSION: On 1 day, more than half the residents surveyed were at risk of consuming an inadequate energy intake, which over-time, may result in body weight loss. Although wastage was not excessive and energy served was adequate, the amount of food eaten was insufficient to meet energy and calcium requirements for a significant number of residents and it is not possible to consume sufficient vitamin D through food sources.

Determinants of bone density in 30- to 65-year-old women: a co-twin study.

UNLABELLED: Reported effects of body composition and lifestyle on bone mineral density in pre-elderly adult women have been inconsistent. In a co-twin study, we measured bone mineral density, lean and fat mass, and lifestyle factors. Analyzing within pair differences, we found negative associations between bone mineral density and tobacco use (2.3-3.3% per 10 pack-years) and positive associations with sporting activity and lean and fat mass. INTRODUCTION: Reported effects of body composition and lifestyle of bone mineral density in pre-elderly adult women have been inconsistent. METHODS: In a co-twin study of 146 female twin pairs aged 30 to 65 years, DXA was used to measure bone mineral density at the lumbar spine, total hip, and forearm, total body bone mineral content, and lean and fat mass. Height and weight were measured. Menopausal status, dietary calcium intake, physical activity, current tobacco use, and alcohol consumption were determined by questionnaire. Within-pair differences in bone measures were regressed through the origin against within-pair differences in putative determinants. RESULTS: Lean mass and fat mass were associated with greater bone mass at all sites. A discordance of 10 pack-years smoking was related to a 2.3-3.3% (SE, 0.8-1.0) decrease in bone density at all sites except the forearm, with the effects more evident in postmenopausal women. In all women, a 0.8% (SE, 0.3) difference in hip bone mineral density was associated with each hour per week difference in sporting activity, with effects more evident in premenopausal women. Daily dietary calcium intake was related to total body bone mineral content and forearm bone mineral density (1.4 +/- 0.7% increase for every 1000 mg). Lifetime alcohol consumption and walking were not consistently related to bone mass. CONCLUSION: Several lifestyle and dietary factors, in particular tobacco use, were related to bone mineral density. Effect sizes varied by site. Characterization of determinants of bone mineral density in midlife and thereafter may lead to interventions that could minimize postmenopausal bone loss and reduce osteoporotic fracture risk.

Changes in body composition as determinants of longitudinal changes in bone mineral measures in 8 to 26-year-old female twins.

Between 1990 and 1998, we conducted a longitudinal study of 286 female twins aged 8 to 25 years at baseline (60 monozygotic (MZ) pairs, 44 dizygotic (DZ) pairs and 78 unpaired twins), measured on average 2.4 times (range 2-6) with an average of 1.8 years between measurements (range 0.7-6.7 years). Areal bone mineral density (ABMD) at the lumbar spine, total hip and femoral neck, total body bone mineral content (BMC), total body soft tissue composition (lean mass and fat mass) were measured by dual-energy X-ray absorptiometry, and height and menarchial status were also recorded. Median annual changes in height were negligible at 4 years post-menarche. During the 'linear growth' period up to 4 years post-menarche, ABMD at the lumbar spine, total hip and femoral neck increased with annual change in lean mass by 1.7 (S.E.0.1), 1.4 (0.1) and 1.0 (0.1) percent per kilogram per year, respectively (all p<0.001), independently of changes in fat mass or height. During the 'post-linear growth' period, ABMD at the total hip and femoral neck increased with annual change in fat mass by 0.3 (0.1) and 0.5 (0.1) percent per kilogram per year (all p < 0.01), independent of change in lean mass. Annual changes in total body BMC were associated with annual changes in lean mass (1.9 (0.2) percent per kilogram), in fat mass (1.3 (0.2) percent per kilogram) and in height (0.7) (0.2) percent per centimeter) during linear growth, and in fat mass (1.0 (0.1)) and lean mass (0.6 (0.1)) percent per kilogram post-linear growth (all p < 0.001). We conclude that changes in bone mineral measures are strongly associated with changes in lean mass during linear growth, while post-linear growth, changes in fat mass are the predominant, although weaker, predictor. These findings suggest that the strong cross-sectional association between bone mineral measures and lean mass is established during growth and development, and that fat mass emerges as a more powerful determinant of bone change in healthy adult females.

Association of birth weight and current body size to blood pressure in female twins.

It has been proposed that low birth weight is associated with high levels of blood pressure in later life. The aim of this study was to assess the relationship of blood pressure to birth weight and current body size during growth and adulthood. A total of 711 female multiple births, with one group of 244 in their growth phase mean age 12.0 (2.3)(SD) years and the other of 467 adults (mean age 35.2 (12.6) years), had height, weight and both systolic (SBP) and diastolic (DBP) blood pressures measured, and self-reported their birth weight. Regression analyses were performed to assess the cross-sectional and within-pair associations of blood pressure to birth weight, with and without adjustments for current body size. Within-pair analysis was based on 296 twin pairs. Cross-sectionally, a reduction in birth weight of 1 kg was associated with 2 to 3 mm Hg higher age-adjusted SBP, which was of marginal significance and explained about 2% of the population variance. Adjustment for body mass index did not significantly change this association. Within-pair analyses found no association between birth weight and SBP or DBP,even after adjusting for current body size. After age, current body size was the strongest predictor of systolic BP. The weak association of blood pressure to birth weight cross-sectionally is of interest, but any within-pair effect of birth weight on blood pressure must be minimal compared with the effect of current body size.

Self-reported ballet classes undertaken at age 10-12 years and hip bone mineral density in later life.

The major effect of weightbearing exercise on adult bone mass may be exerted during childhood. We examined the relationship between reported hours of ballet classes per week undertaken as a child and adult bone mineral density (BMD) at the hip, spine, and forearm. We performed a retrospective cohort study in 99 female retired dancers (mean age 51 years, SD 14 years) and 99 normal controls, derived from a twin study, matched hierarchically for age, height, weight and menopausal status. Starting age of ballet was recalled and weekly hours of ballet as a child was self-reported on two occasions. BMD was measured using dualenergy X-ray absorptiometry and reported as a Z-score. Self-reported hours of ballet class undertaken per week at each age between 10 and 12 years was positively associated with a difference in BMD between dancers and controls at both the femoral neck site (beta = 0.73, p = 0.001) and the total hip site (beta = 0.55, p < 0.01). These associations were unaffected by adjustment for covariates including measures of adult activity (current physical activity, years of fulltime ballet), measures of menstrual disturbance (age of menarche, history of irregular menses), dietary history (calcium intake as a child, adolescent or adult) or lifestyle factors (lifetime smoking, lifetime alcohol). Although starting age of ballet was negatively associated with weight-adjusted within-pair hip BMD difference, it was no longer associated after adjustment for weekly hours of ballet. There was no relationship between hours of ballet undertaken as a child and differences in BMD at the lumbar spine or upper limb, at any age. Our data suggest that classical ballet classes undertaken between the ages of 10 and 12 years are independently and positively associated with a difference in hip BMD between dancers and controls. The findings are consistent with the hypothesis that this age range identifies a stage of development when the proximal femur is particularly responsive to weightbearing exercise.

Genetic, common environment, and individual specific components of variance for bone mineral density in 10- to 26-year-old females: a twin study.

Lean mass and areal bone mineral density at the lumbar spine, femoral neck, and total forearm were measured in 215 volunteer female twin pairs (122 monozygotic, 93 dizygotic), aged 10-26 years, using dual energy X-ray absorptiometry. The study was conducted in Melbourne from 1990 to 1994. Under the classic twin model, there was evidence for a genetic component of variation in bone mineral density, adjusted for age or for age and lean mass, at all sites. Adjusting for lean mass almost halved the genetic variances in the adolescent years of peak growth, during which genetic variances peaked. Genetic variances were reduced in the late teenage years and increased in early adulthood. The latter may reflect gene-environment interactions or covariation. Importantly, there was evidence for environmental effects shared by twins on lumbar spine and femoral neck bone mineral density, even when adjusted for lean mass as well as age. These were greatest during the late teenage years, abated over the years when pairs started to live apart, and appear to be independent of lean mass during adolescence but not in early adulthood. In summary, the genetic and environmental etiology of bone mineral density is more complex than previously thought.