Higher habitual sodium intake is not detrimental for bones in older women with adequate calcium intake.

Based on the calciuric effect of sodium (Na), it has been speculated, although not proven, that higher Na intake might have a detrimental effect on bone health. The objective was to determine the relationship between Na intake (expressed as urinary Na) and bone mineral density/content (BMD/BMC) during a 3-year study. Participants were healthy, postmenopausal, Caucasian women (n = 136 at baseline) with no medications affecting bone. After baseline screening, half were instructed to reduce sodium intake to approximately 1,500 mg/day (intervention). The other half remained on habitual intake of approximately 3,000 mg/day (control). All subjects were given calcium and vitamin D supplements to achieve recommended levels. Anthropometries, densitometry, blood and 24-h urine analyses, and dietary and activity records were assessed every 6 months. Data were analyzed as a continuum, irrespective of the initial assignment to a control or intervention group, using random effects regressions with repeated measures analysis of variance to examine changes over time. Results showed that subjects with higher Na intake had higher BMD in the forearm and spine at baseline and all subsequent time-points (p < 0.01). In the forearm, time and higher urinary calcium modified results, producing a curvilinear decrease in BMD (p < 0.01). In the spine, more active individuals had higher BMD at all time-points. We conclude that higher sodium intake, within the range consumed, had a positive effect on some skeletal sites and no adverse effect on bone in women who had adequate calcium and vitamin D intake.

Habitual and low-impact activities are associated with better bone outcomes and lower body fat in older women.

The influence of habitual and low-impact physical activity (PA) on bone health and soft tissue including bone-free lean (BFL) and fat mass is less elucidated than the influence of high-impact activities. This study examines the interactive effects of PA and soft tissue on bone mineral density (BMD) and content (BMC) in healthy Caucasian women, aged 68.6 +/- 7.1 years, with body mass index (BMI) of 26.0 +/- 3.8 kg/m(2) evaluated at baseline and every 6 months for 3 years. Measurements/assessments included BMD/BMC and soft tissue (by dual-energy X-ray absorptiometry), anthropometrics, dietary intake, and PA. Activities assessed were past activity, present heavy housework, gardening, do-it-yourself activities, stair-climbing, walking, walking pace, sports/recreation, and total activity. Baseline analyses revealed significant positive associations between past activity, heavy housework, faster-paced walking, BFL, and BMD/BMC of various skeletal sites. Prospective analyses showed subjects with more walking hours/week had significantly higher BMD/BMC of several skeletal sites (P < 0.05). Stratification by cumulative (over 3 years) median for heavy housework, walking, sports/recreational, and total activities revealed higher BMD and BMC in the femur and spine (P = 0.01) in subjects with those activities above median. Multivariate analysis of covariance results revealed that weight had the strongest influence on BMD and BMC, followed by BFL. Various modes of PA were negatively associated with BMI and fat but not with BFL. In conclusion, heavy housework, walking (faster pace), sports/recreational activities, and overall total participation in low-impact PA were beneficial for bone and for achieving more favorable body weight and fat but were not associated with BFL. The results indicate that even habitual activities engaged in by older women could benefit their bone and diminish body fat.

Measuring body composition in overweight individuals by dual energy x-ray absorptiometry.

BACKGROUND: Dual energy x-ray absorptiometry (DXA) is widely used for body composition measurements in normal-weight and overweight/obese individuals. The limitations of bone densitometers have been frequently addressed. However, the possible errors in assessing body composition in overweight individuals due to incorrect positioning or limitations of DXA to accurately assess both bone mineral density and body composition in obese individuals have not received much attention and are the focus of this report. DISCUSSION: We discuss proper ways of measuring overweight individuals and point to some studies where that might not have been the case. It appears that currently, the most prudent approach to assess body composition of large individuals who cannot fit under the scanning area would be to estimate regional fat, namely the regions of thigh and/or abdomen. Additionally, using two-half body scans, although time consuming, may provide a relatively accurate measurement of total body fat, however, more studies using this technique are needed to validate it. SUMMARY: Researchers using bone densitometers for body composition measurements need to have an understanding of its limitations in overweight individuals and address them appropriately when interpreting their results. Studies on accuracy and precision in measurements of both bone and soft tissue composition in overweight individuals using available densitometers are needed.

Validation of the use of the hand for estimating bone mineral density in other skeletal sites by DXA in healthy and osteoarthritic women.

Hand bone mineral density (BMD) by DXA has mainly been used to assess bone loss in rheumatoid arthritis patients. Its use in healthy subjects is limited. The following study was conducted to determine if measurements of hand BMD could estimate ones risk of osteoporosis and predict BMD in other skeletal sites. Subjects consisted of 134 Caucasian females (57-88 yr, 46 with self-reported osteoarthritis and the rest healthy). BMD was measured in the hand, forearm, hip, spine, and total body with the Lunar DPX-MD instrument. Subjects were divided into those with osteoarthritis (OA) and those without and were examined separately, as well as together. Hand BMD correlated significantly with all skeletal sites for the whole population and for each group. Pearson r for the whole population ranged from 0.56 in the lumbar spine to 0.82 in the forearm. Subjects with OA had higher correlations for most sites. Subjects' T-scores, derived from the reference population of young normal adult women, for hip, spine, forearm, and whole body correlated highly with hand BMD. To test how accurately hand BMD could predict BMD in other skeletal sites, we generated regression models from three-fourth of our subjects (n = 102). Based on the resulting regression equations and measured hand BMD, we calculated the predicted values of the BMD in all other skeletal sites for the remaining one-fourth of the subjects (n = 32). The predictive mean square errors, calculated from the observed and predicted values for each skeletal site, were small and below the cutoff values in F-distribution. In conclusion, hand BMD has a potential to establish one's risk for osteoporosis as well as reasonably accurately predict BMD in other skeletal sites. The hand BMD measurement in general, whether a part of DXA or as a separate instrument, might have a potential to be used for mass screening and in prospective studies to determine risk of fractures.

Cognitive function in relation with bone mass and nutrition: cross-sectional association in postmenopausal women.

BACKGROUND: It has been suggested that bone loss and cognitive decline are co-occurring conditions, possibly due to their relationship with estrogen. Cognitive decline has been associated with various nutritional deficiencies as well. The purpose of this study was to determine if cognitive function is related to bone mineral density of various skeletal sites as well as to various dietary components. METHODS: Cross-sectional study with 97 healthy, Caucasian, postmenopausal women (59.4-85.0 years) enrolled in a larger longitudinal study, investigating the effects of sodium on bone mass. The subjects were divided into two groups based on cognition scores. Group 1 represented lower and Group 2 higher scores on cognitive function. Bone mineral density from the whole body, lumbar spine, femur and forearm were measured with the Lunar DPX-MD instrument. Anthropometry was measured by standard methods. Cognition was assessed using the Mini Mental State Examination. Cumulative (over 2 years) dietary intake from 3-day records was analyzed by Food Processor(R) (ESHA Research, Salem, OR) and cumulative physical activity was assessed using Allied Dunbar National Fitness Survey for older adults. RESULTS: Subjects' cognition scores ranged from 22-30 (normal, 27-30), indicating all subjects had either mild or no cognitive impairment. Multiple Analysis of Covariance adjusted for age, height, weight, physical activity, alcohol, calcium, sodium and energy intake, showed a statistically significant association between cognition and bone mineral density of all measurable sites (eta2 = 0.21, P < 0.01). However, after Analysis of Covariance follow-up tests and Bonferroni correction, the differences for individual bone sites diminished, though Group 2 had higher adjusted means for all sites except for the femoral neck, Ward's triangle and trochanter. There was a positive significant association between cognition score and carbohydrate and potassium intake (eta2 = 0.07, P = 0.050). Group 2 did have a significantly higher potassium intake (P = 0.023). In multiple regression, saturated fat had a significant negative relationship with cognitive function. CONCLUSIONS: It appears mild degree of cognitive impairment may be a marker for lower bone mineral density as well as for a diet lower in carbohydrate and potassium intake, and higher in saturated fat. Consequently, older women with cognitive impairment may benefit of being screened for potential bone loss and poor nutrition.

Association between dietary conjugated linoleic acid and bone mineral density in postmenopausal women.

OBJECTIVE: To determine if dietary conjugated linoleic acid (CLA) is associated with bone mineral density (BMD) of different skeletal sites in postmenopausal women. METHODS: A cross-sectional analysis in 136 Caucasian, healthy, postmenopausal women, mean age 68.6 years. BMD and soft tissue were assessed by dual energy x-ray absorptiometry (DXA). Energy, calcium, protein, fat, CLA and other relevant nutrients were estimated using 3 day dietary records. Supplement use was recorded as well. Current and past physical activity were determined using the Allied Dunbar National Fitness Survey for older adults. RESULTS: CLA (63.1 +/- 46.8 mg, mean +/- SD) was a significant predictor of Ward's triangle BMD (p = 0.040) in a multiple regression model containing years since menopause (18.5 +/- 8.4 y), lean tissue, energy intake (1691 +/- 382 kcal/day) dietary calcium (873 +/- 365 mg), protein (70.6 +/- 18.6 g), fat (57.9 +/- 23.9 g), zinc (19.2 +/- 13.6 mg), and current and past physical activity, with R(2)(adj) = 0.286. Subjects were also divided into groups below (Group 1) and above (Group 2) the median intake for CLA. Group 2 had higher BMD in the forearm, p = 0.042, and higher BMD in the hip, lumbar spine and whole body, however statistical significance was not reached. CONCLUSION: These findings indicate dietary CLA may positively benefit BMD in postmenopausal women. More studies are warranted examining the relationship between dietary CLA and BMD.

Association of physical performance measures with bone mineral density in postmenopausal women.

OBJECTIVE: To investigate the association between physical performance measures and bone mineral density (BMD) in older women. DESIGN: Cross-sectional analysis. SETTING: University research laboratory. PARTICIPANTS: Healthy postmenopausal women (N=116; mean age +/- standard deviation, 68.3+/-6.8y) in self-reported good health who were not taking medications known to affect bone, including hormone replacement therapy. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Anthropometrics and BMD of the hip, spine, whole body, and forearm. Physical performance measures included normal and brisk 8-m gait speed, normal step length (NSL), brisk step length (BSL), timed 1-leg stance (OLS), timed sit-to-stand (STS), and grip strength. RESULTS: NSL, BSL, normal gait speed, brisk gait speed, OLS, and grip strength correlated significantly with several skeletal sites ( r range, .19-.38; P <.05). In multiple regression models containing body mass index, hours of total activity, total calcium intake, and age of menarche, NSL, BSL, normal and brisk gait speeds, OLS, and grip strength were all significantly associated with BMD of various skeletal sites (adjusted R 2 range, .11-.24; P <.05). Analysis of covariance showed that subjects with longer step lengths and faster normal and brisk gait speeds had higher BMD at the whole body, hip, and spine (brisk speed only). Those with a longer OLS had greater femoral neck BMD, and those with a stronger grip strength had greater BMD in the whole body and forearm ( P <.05). STS was not related to any skeletal site. CONCLUSIONS: Normal and brisk gait speed, NSL, BSL, OLS, and grip strength are all associated with BMD at the whole body, hip, spine, and forearm. Physical performance evaluation may help with osteoporosis prevention and treatment programs for postmenopausal women when bone density scores have not been obtained or are unavailable.

Weight loss favorably modifies anthropometrics and reverses the metabolic syndrome in premenopausal women.

OBJECTIVE: To determine the effects of a weight loss program, including dietary modifications, increased physical activity and dietary supplement (L-carnitine or placebo) on anthropometrics, leptin, insulin, the metabolic syndrome (MS) and insulin resistance in overweight /obese premenopausal women. METHODS: Participants consumed a hypocaloric diet; 30% protein, 30% fat and 40% carbohydrate in addition to increasing number of steps/day. Carnitine supplementation followed a randomized double blind protocol. Protocol lasted for 10 weeks. Seventy subjects (35 in the control and 35 in the carnitine group) completed the intervention. Anthropometrics, plasma insulin and leptin concentrations and body composition were measured. The number of subjects with the MetSyn and insulin resistance, were assessed at baseline and post-intervention. RESULTS: Because there were no significant differences between the carnitine and the placebo groups for all measured parameters, participants were grouped together for all analysis. Subjects decreased total energy (-26.6%, p < 0.01) and energy from carbohydrate (-17.3%, p < 0.01) and increased energy from protein by 67% (p < 0.01) and number of steps/day (42.6%, p < 0.01). Body weight (-4.6%, p < 0.001), body mass index (-4.5%, p < 0.01), waist circumference (-6.5%, p < 0.01), total fat mass (-1.7%, p < 0.01), trunk fat mass (-2.0%, p < 0.01), insulin (- 17.9%, p < 0.01) and leptin (-5.9%, p < 0.05) decreased after the intervention. Ten of 19 participants with insulin resistance became insulin sensitive and 7 of 8 participants with the MetSyn no longer had the syndrome after the intervention. CONCLUSION: Moderate increases in physical activity and a hypocaloric/high protein diet resulted in multiple beneficial effects on body anthropometrics and insulin sensitivity. Realistic dietary and physical activity goals must be the focus of intervention strategies for overweight and obese individuals.

Hip geometry and its role in fracture: what do we know so far?

As the number of hip fractures continues to rise, finding better ways to identify people at risk becomes crucial. In the past decade, several measures of hip geometry have been studied as possible risk factors for hip fracture. Among them, hip axis length (HAL) shows the greatest promise for enhancing fracture risk assessment in the clinical setting, followed by neck shaft angle (NSA) and femoral neck width (FNW). Studies have shown that both age and/or a loss of body weight are associated with changes in some of the geometric parameters, which subsequently indicate the decrease in hip strength. The greater hip strength in black women and men resulting in a lower incidence of fractures compared with white women is also attributed to more favorable geometric parameters. Asian women, who have a lower incidence of fractures than white women, have a shorter HAL and a smaller NSA. In general, a longer HAL and a greater NSA and FNW all increase the risk of fracture, though controversies exist due to the use of different subject populations and measurement tools. Overall evidence suggests assessing hip geometry para-meters can significantly improve the ability of identifying people at risk of fracture, but more development in measurement software and more research are necessary to make it applicable in clinical settings.

Critical factors for bone health in women across the age span: how important is muscle mass?

OBJECTIVES/DESIGN: This cross-sectional study of 113 healthy white women, 20-88 years of age, evaluated relationships between bone mineral density (BMD), body composition, calcium (Ca) intake, and physical activity. The analysis was performed in the entire cohort and in groups divided by reproductive/menopausal status (premenopausal, perimenopausal, early postmenopausal, and late postmenopausal). METHODS: BMD and body composition were measured with Lunar DPX-MD densitometer using specialized software for total body, spine, femur, and forearm. Ca intake from food and supplements was assessed by a food frequency questionnaire. Past physical activity and past and present walking were assessed only in the older cohort using modified version of the Allied Dunbar National Fitness Survey for Older Adults. RESULTS: The results showed significant reduction of both total body BMD and lean body mass (LBM) of 13% and 12%, respectively, with age. LBM was the strongest determinant of BMD in various skeletal sites in the entire cohort and groups. Ca was positively associated with BMD of various regions of hip in the entire cohort and in the youngest and oldest subjects (r ranging from 0.32-0.56, P <.05, in simple regression), but not in perimenopausal and early postmenopausal women. Past activity (sports and recreation) was positively associated with BMD in total body, spine, hip, and forearm (r ranging from 0.26-0.37, P <.05). Various modes of present walking were positively associated with BMD in regions of femur and forearm. CONCLUSIONS: These results reveal the importance of lean tissue acting independently on bone at different skeletal sites in women across age groups as well as the positive effects on BMD of Ca in the youngest and oldest women and life-long engagement in physical activity in older women.

To drink or not to drink: how are alcohol, caffeine and past smoking related to bone mineral density in elderly women?

OBJECTIVES: To determine relationship between alcohol, caffeine, past smoking and bone mineral density of different skeletal sites in elderly women, accounting for other biological and life-style variables. METHODS/DESIGN: A cross-sectional study in 136 Caucasian women, mean +/- SD age 68.6 +/- 7.1 years, all healthy and free of medications affecting bones, including estrogen. Bone mineral density (BMD) of multiple skeletal regions and body composition were measured by dual X-ray absorptiometry. Serum vitamin D (25-OHD) and parathyroid hormone (PTH) were analyzed and used as confounders. Calcium (Ca) intake was assessed by food frequency questionnaire. Alcohol and caffeine consumption was assessed by questionnaires determining frequency, amount and source of each. There were no current smokers, but the history of smoking was recorded, including number of years and packages smoked/day. Past physical activity was assessed by Allied Dunbar National Fitness Survey and used as confounder. Statistical significance was considered at p or=median, 750 mg/day). The past smokers who smoked on average 24 years of approximately 1 pack cigarettes/day had lower BMD in total body, spine and femur than never-smokers when evaluated in subgroup analyses, and the association was attenuated in participants with >or=median Ca intake. There was no significant association between past smoking and BMD of any skeletal site in multiple regression analyses. CONCLUSION: The results support the notion that consumption of small/moderate amount of alcohol is positively, while caffeine and past smoking are negatively associated with most of the skeletal sites, which might be attenuated with Ca intake above 750 mg/day.