Most pediatric exercise intervention studies that evaluate the effect on skeletal traits include volunteers and follow bone mass for less than 3 years. We present a population-based 6-year controlled exercise intervention study in children with bone structure and incident fractures as endpoints. Fractures were registered in 417 girls and 500 boys in the intervention group (3969 person-years) and 835 girls and 869 boys in the control group (8245 person-years), all aged 6 to 9 years at study start, during the 6-year study period. Children in the intervention group had 40 minutes daily school physical education (PE) and the control group 60 minutes per week. In a subcohort with 78 girls and 111 boys in the intervention group and 52 girls and 54 boys in the control group, bone mineral density (BMD; g/cm(2) ) and bone area (mm(2) ) were measured repeatedly by dual-energy X-ray absorptiometry (DXA). Peripheral quantitative computed tomography (pQCT) measured bone mass and bone structure at follow-up. There were 21.7 low and moderate energy-related fractures per 1000 person-years in the intervention group and 19.3 fractures in the control group, leading to a rate ratio (RR) of 1.12 (0.85, 1.46). Girls in the intervention group, compared with girls in the control group, had 0.009?g/cm(2) (0.003, 0.015) larger gain annually in spine BMD, 0.07?g (0.014, 0.123) larger gain in femoral neck bone mineral content (BMC), and 4.1?mm(2) (0.5, 7.8) larger gain in femoral neck area, and at follow-up 24.1?g (7.6, 40.6) higher tibial cortical BMC (g) and 23.9?mm(2) (5.27, 42.6) larger tibial cross-sectional area. Boys with daily PE had 0.006?g/cm(2) (0.002, 0.010) larger gain annually in spine BMD than control boys but at follow-up no higher pQCT values than boys in the control group. Daily PE for 6 years in at study start 6- to 9-year-olds improves bone mass and bone size in girls and bone mass in boys, without affecting the fracture risk.
Comment In: J Bone Miner Res. 2014 Jun;29(6):1322-424764102
The relationships between objectively measured abdominal and gynoid adipose mass with the prospective risk of myocardial infarction (MI) has been scarcely investigated. We aimed to investigate the associations between fat distribution and the risk of MI.
Total and regional fat mass was measured using dual-energy X-ray absorptiometry (DEXA) in 2336 women and 922 men, of whom 104 subsequently experienced an MI during a mean follow-up time of 7.8 years.
In women, the strongest independent predictor of MI was the ratio of abdominal to gynoid adipose mass (hazard ratio (HR)=2.44, 95% confidence interval (CI) 1.79-3.32 per s.d. increase in adipose mass), after adjustment for age and smoking. This ratio also showed a strong association with hypertension, impaired glucose tolerance and hypertriglyceridemia (P
Previous studies have indicated that fat distribution is important in the development of cardiovascular disease (CVD). We investigated the association between fat distribution, as measured by dual energy X-ray absorptiometry (DXA), and the incidence of stroke.
A cohort of 2751 men and women aged =40 years was recruited. Baseline levels of abdominal, gynoid and total body fat were measured by DXA. Body mass index (BMI, kg?m(-2)) was calculated. Stroke incidence was recorded using the regional stroke registry until subjects reached 75 years of age.
During a mean follow-up time of 8 years and 9 months, 91 strokes occurred. Of the adiposity indices accessed abdominal fat mass was the best predictor of stroke in women (hazard ratio (HR)=1.66, 95% confidence interval (CI)=1.23-2.24 per standard deviation increase), whereas the ratio of gynoid fat to total fat mass was associated with a decreased risk of stroke (HR=0.72, 95% CI=0.54-0.96). Abdominal fat mass was the only of the adiposity indices assessed that was found to be a significant predictor of stroke in men (HR=1.49, 95% CI=1.06-2.09). The associations between abdominal fat mass and stroke remained significant in both women and men after adjustment for BMI (HR=1.80, 95% CI=1.06-3.07; HR=1.71, 95% CI=1.13-2.59, respectively). However, in a subgroup analyses abdominal fat was not a significant predictor after further adjustment for diabetes, smoking and hypertension.
Abdominal fat mass is a risk factor for stroke independent of BMI, but not independent of diabetes, smoking and hypertension. This indicates that the excess in stroke risk associated with abdominal fat mass is at least partially mediated through traditional stroke risk factors.
Abdominal obesity is a major risk factor for diabetes. Dual-energy x-ray absorptiometry (DXA) of the lumbar spine provides an index of abdominal fat.
Our objective was to examine the hypothesis that DXA-derived abdominal fat measurement in women undergoing osteoporosis investigation predicts risk for subsequent diagnosis of diabetes.
This historical cohort study was derived from the Manitoba Bone Density Program Database for the Province of Manitoba, Canada.
30,252 nondiabetic women aged 40 yr and older were referred for baseline osteoporosis assessment with DXA between January 1990 and March 2007.
Each woman's longitudinal provincial health service record was assessed for the presence of diabetes diagnosis codes after DXA testing.
During 5.2 + or - 2.6 yr of observation, 1252 (4.1%) women met the case definition for diabetes. A greater proportion of abdominal fat from spine DXA was strongly related to subsequent diabetes diagnosis in models adjusted for age, body mass index, and other comorbidities. Those in the highest quintile had 3.56 (95% confidence interval = 2.67-4.75) times the risk for subsequent diabetes diagnosis compared with those in the lowest (reference) quintile. Fat from hip DXA was not predictive of subsequent diabetes after adjustment for the same variables (1.00, 95% confidence interval = 0.79-1.26).
Predictive information about diabetes risk can be obtained from spine DXA scans performed for osteoporosis risk assessment. This is consistent with evidence linking abdominal fat with insulin resistance and the metabolic syndrome.
Differences in subcutaneous abdominal adipose tissue (SAT) fat cell size and number (cellularity) are linked to insulin resistance. Men are generally more insulin resistant than women but it is unknown whether there is a gender dimorphism in SAT cellularity. The objective was to determine SAT cellularity and its relationship to insulin sensitivity in men and women.
In a cohort study performed at an outpatient academic clinic in Sweden, 798 women and 306 men were included. Estimated SAT mass (ESAT) was derived from measures of dual-energy X-ray absorptiometry and a formula. SAT biopsies were obtained to measure mean fat cell size; SAT adipocyte number was obtained by dividing ESAT with mean fat cell weight. Fat cell size was also compared with level of insulin sensitivity in vivo.
Over the entire range of body mass index (BMI) both fat cell size and number correlated positively with ESAT in either sex. On average, fat cell size was larger in men than in women, which was driven by significantly larger fat cells in non-obese men compared with non-obese women; no gender effect on fat cell size was seen in obese subjects. For all subjects fat cell number was larger in women than men, which was driven by a gender effect among non-obese individuals (P
In this study, we evaluate the ability of digitized digital X-ray radiogrammetry (DXR) bone mineral density (BMD) to identify women with reduced BMD at femoral neck, assessed by dual-energy X-ray absorptiometry (DXA). The study population contained women with recent low-energy distal radius fracture and women recruited from the general population, all aged 50 yr or older. The correlation between hand BMD and femoral neck BMD was r=0.65 (p
The accuracy of predictive equations for calculating resting energy expenditure (REE) in elderly people has been questioned. Aging is associated with progressive declines in REE, which partly is explained by loss of fat free mass (FFM). Against this background we aimed to identify the most accurate predictive equation for REE in octogenarian men, taking body composition into account and using indirect calorimetry as reference value. REE was measured in 22 men (mean age 82.6±0.3years) and compared with six predictive equations: two based on FFM and four based on body weight, height and/or age. FFM was derived from Dual-energy X-ray absorptiometry analyses. Spearman's rank correlations showed a moderate to high positive monotonic correlation (r=0.62 to 0.79) between measured and calculated REE (all p
Non-expert clinical practitioners who had received bone density reports based on 10-year absolute fracture risk were surveyed to determine their response to this new system. Absolute fracture risk reporting was well received and was strongly preferred to traditional T-score-based reporting. Non-specialist physicians were particularly supportive of risk-based bone mineral density (BMD) reporting.
Absolute risk estimation is preferable to risk categorization based upon BMD alone. The objective of this study was to specifically assess the response of non-expert clinical practitioners to this approach.
In January 2006, the Province of Manitoba, Canada, started reporting 10-year osteoporotic fracture risks for patients aged 50 years and older based on the hip T-score, gender, age, and multiple clinical risk factors. In May 2006 and October 2006, a brief anonymous survey was sent to all physicians who had requested a BMD test during 2005 and 206 responses were received.
When asked whether the report contained the information needed to manage patients, the mean score for the absolute fracture risk report was higher than for the T-score-based report (p
To determine if inequities in access to osteoporosis investigation [dual-energy x-ray absorptiometry (DXA) testing] and treatment (bisphosphonate, calcitonin, and/or raloxifene) exist among older women in a region with universal health care coverage.
Community-dwelling women aged 65-89 years residing within 2 regions of Ontario, Canada were randomly sampled. Data were collected by standardized telephone interview. Potential correlates of DXA testing (verified by physician records), and current treatment were grouped by type as: "predisposing characteristics," "enabling resources," or "need factors" based on hypothesized relationships formulated before data collection. Variables associated with each outcome independent of "need factors" identified inequities in the system.
Of the 871 participants (72% response rate), 55% had been tested by DXA and 20% were receiving treatment. Using multiple variable logistic regression to adjust for need factors, significant inequities in access to DXA testing existed by age, health beliefs, education, income, use of preventive health services, region, and provider sex. DXA testing mediated access to treatment; 34% of those having had a DXA were treated compared with 2% of those who did not. Among women with osteoporosis, correctly reporting that their DXA test indicated osteoporosis and higher perceived benefits of taking pharmacological agents for osteoporosis were associated with treatment.
Significant inequities in access to fracture prevention exist in a region with universal health care coverage. Improved access to DXA and better communication to patients of both their DXA results and the benefits of treatment has the potential to reduce the burden of osteoporosis.