Role of nutrition and exercise in osteoporosis

Relationship between bone mineral density and dietary intake of β-carotene, vitamin C, zinc and vegetables in postmenopausal Korean women: a cross-sectional study

Objective

To examine the relationship between nutritional intake and bone mineral density (BMD) in postmenopausal Korean women.

Methods

Dietary intake was recorded in postmenopausal Korean women using a semiquantitative questionnaire. The frequency of consumption of various food groups and nutrient intake were calculated. BMD T-scores were measured at the lumbar spine, femoral neck and total hip using dual-energy X-ray absorptiometry. Associations between T-scores and dietary intake were analysed using partial correlation coefficients and multiple linear regression analysis.

Results

A total of 189 postmenopausal women were included in the study. β-Carotene intake was positively correlated with the lumbar spine T-score. Sodium and vitamin C intake were positively associated and folate intake negatively associated with the femoral neck T-score. Sodium, zinc and vitamin C intake were positively correlated and potassium intake was negatively correlated with the total hip T-score. Vegetable intake showed a positive association with the femoral neck and total hip T-scores.

Conclusion

In postmenopausal Korean women, β-carotene, vitamin C, zinc and sodium intakes were positively associated with bone mass. Furthermore, frequency of vegetable consumption was positively associated with femoral neck and total hip T-scores.

Influence of food restriction combined with voluntary running on bone morphology and strength in male rats

Athletes, in particular endurance athletes and dancers, are chronically exposed to a state of low energy availability due to insufficient dietary energy intake and massive exercise energy expenditure. Low energy availability sometimes causes bone fragility, thereby increasing the risk of bone disorders. Although the decrease in energy availability shows no sexual dimorphism, epidemiological studies have reported that bone disorders are less frequent in male athletes than in female athletes. We hypothesized that bone tissue was not affected by low energy availability in males. The purpose of this study was to examine the influence of food restriction combined with voluntary running training on bone morphology and strength in adult male rats. Fourteen-week-old male Sprague-Dawley rats were divided randomly into four groups: control (C) group, food restriction (R) group, exercise (Ex) group, and food restriction plus exercise (REx) group. For the R and REx groups, 30 % food restriction was carried out in comparison with the C group. Bone strength, bone mineral density (BMD), bone architecture, and bone turnover rate were measured after a 13-week experimental period. Bone strength was not significantly lower in the REx group compared with the C group. BMD and trabecular bone volume showed no difference among groups. These findings indicate that bone morphology and strength were little affected by food restriction combined with exercise training in adult male rats.

Diet and lifestyle associated with increased bone mineral density: cross-sectional study of Japanese elderly women at an osteoporosis outpatient clinic

BACKGROUND

Several studies have already demonstrated that lifestyle characteristics, such as physical activity, smoking, and alcohol intake, are associated with bone mineral density (BMD). Coffee intake was shown to be negatively associated with BMD, whereas tea drinking was reported to be associated with increased BMD. A review of the literature, however, revealed that few studies have described the association between BMD and lifestyle, including characteristic Japanese foods such as fish, natto, and Japanese green tea. The aim of this study was to identify lifestyle factors associated with BMD.

METHODS

A total of 632 women age > or =60 years were enrolled in this study. Subjects were interviewed about their lifestyle by means of a questionnaire regarding the consumption pattern of dietary items. BMD was measured at the lumbar spine by dual energy X-ray absorptiometry.

RESULTS

The BMD was higher in subjects with the habits of alcohol drinking, green tea drinking, and physical activity and lower in those with the habits of smoking and cheese consumption. Multiple regression analysis showed that factors associated with BMD were smoking, alcohol consumption, green tea drinking, and physical activity after adjusting for age and body mass index (BMI).

CONCLUSIONS

In this cross-sectional study at an osteoporosis outpatient clinic, patients with the habits of alcohol drinking, green tea drinking, and physical activity had significantly higher BMD, and those who smoked had significantly lower BMD than patients without each habit after adjusting for age, BMI, and other variables regarding lifestyle.

Physiological and Metabolic Aspects of Very Prolonged Exercise with Particular Reference to Hill Walking

Hill walking is a popular recreational activity in the developed world, yet it has the potential to impose severe stress simultaneously upon several regulatory systems. Information regarding the physiological strain imposed by prolonged walking outdoors in adverse climatic conditions was reported almost four decades ago and recent research has extended some of this work. These data indicate that once the walker fatigues and starts to slow or stops walking altogether, the rate of heat production falls dramatically. This decrease alone predisposes to the development of hypothermia. These processes, in adverse weather conditions and/or during periods when the level of exertion is low (with low heat production), will be accelerated. Since the majority of walkers pursue this activity in groups, the less fit walkers may be more susceptible to fatigue when exercising at a higher relative intensity compared with their fitter counterparts. The best physiological offset for hypothermia is to maintain heat production by means of exercise, and so fatigue becomes a critical predisposing factor; it is as important to facilitate heat loss, especially during periods of high exertion, as it is to maintain heat production and preserve insulation. This can be partly achieved by clothing adjustments and consideration of the intensity of exercise. Failure to provide adequate energy intake during hill walking activities has been associated with decreased performance (particularly with respect to balance) and impaired thermoregulation. Such impairments may increase susceptibly to both fatigue and injury whilst pursuing this form of activity outdoors. The prolonged low to moderate intensity of activity experienced during a typical hill walk elicits marked changes in the metabolic and hormonal milieu. Available data suggest that during hill walking, even during periods of acute negative energy balance, blood glucose concentrations are maintained. The maintenance of blood glucose concentrations seems to reflect the presence of an alternative fuel source, a hormonally induced increase in fat mobilisation. Such enhancement of fat mobilisation should make it easier to maintain blood glucose by decreasing carbohydrate oxidation and promoting gluconeogenesis, thus sparing glucose utilisation by active muscle. During strenuous hill walking, older age walkers may be particularly prone to dehydration and decreased physical and mental performance, when compared with their younger counterparts. In summary, high rates of energy expenditure and hypohydration are likely to be closely linked to the activity. Periods of adverse weather, low energy intake, lowered fitness or increased age, can all increase the participants' susceptibility to injury, fatigue and hypothermia in the mountainous environment.

Physiological, metabolic, and performance implications of a prolonged hill walk: influence of energy intake

We aimed to examine the effects of different energy intakes on a range of responses that are relevant to the safety of hill walkers. In a balanced design, 16 men completed a strenuous self-paced mountainous hill walk over 21 km, under either a low-energy (2.6 MJ; 616 kcal) intake (LEI) or high-energy (12.7 MJ; 3,019 kcal) intake (HEI) condition. During the hill walk, rectal temperatures were measured continuously, and blood samples for the analysis of metabolites and hormones were drawn before breakfast and immediately after the walk. Subjects also completed a battery of performance tests that included muscular strength, reaction times, flexibility, balance, and kinesthetic differentiation tests. During the LEI, mean blood glucose concentrations leveled off at the low-middle range of normoglycemia, whereas, on the HEI, they were significantly elevated compared with the LEI. The maintained blood glucose concentrations, during the LEI, were probably mediated via the marked fat mobilization, reflected by a two- to fivefold increase in nonesterified fatty acids, 3-hydroxybutyrate, and glycerol concentrations. The LEI group showed significantly slower one- and two-finger reaction time, had an impaired ability to balance, and were compromised in their ability to maintain body temperature, when compared with the HEI group. The modestly impaired performance (particularly with respect to balance) and thermoregulation during the LEI condition may increase susceptibility to both fatigue and injury during the pursuit of recreational activity outdoors.

Tea drinking and bone mineral density in older women

BACKGROUND

High caffeine intake is reportedly a risk factor for reduced bone mineral density (BMD) in women. Most studies, however, are from populations in which coffee drinking predominates and is the major caffeine source. Tea contains caffeine but also has other nutrients, such as flavonoids, that may influence bone mass in different ways.

OBJECTIVE

We examined the relation between tea drinking and BMD in older women in Britain, where tea drinking is common.

METHODS

We measured BMD at the lumbar spine, femoral neck, greater trochanter, and Ward's triangle in 1256 free-living women aged 65-76 y in Cambridge, United Kingdom. Tea drinking was assessed by self-completed questionnaire and women were categorized as tea drinkers or non-tea drinkers.

RESULTS

There were 1134 tea drinkers (90.3%) and 122 non-tea drinkers (9.7%). Compared with non-tea drinkers, tea drinkers had significantly greater ( approximately 5%) mean BMD measurements, adjusted for age and body mass index, at the lumbar spine (0.033 g/cm(2); P = 0.03), greater trochanter (0.028 g/cm(2); P = 0.004), and Ward's triangle (0.025 g/cm(2); P = 0.02). Differences at the femoral neck (0.013 g/cm(2)) were not significant. These findings were independent of smoking status, use of hormone replacement therapy, coffee drinking, and whether milk was added to tea.

CONCLUSIONS

Older women who drank tea had higher BMD measurements than did those who did not drink tea. Nutrients found in tea, such as flavonoids, may influence BMD. Tea drinking may protect against osteoporosis in older women.

Gingival fluid IL-1beta in postmenopausal females on supportive periodontal therapy. A longitudinal 2-year study

Posterior interproximal alveolar bone in 59 women, within 5 years after menopause, was assessed at baseline and after 2 years of supportive periodontal therapy (history of moderate/advanced periodontitis) using digitized image analysis. Baseline lumbar spine bone mineral density, smoking status, and yearly serum estradiol (E2) levels also were obtained to group subjects. An additional 16 non-periodontitis postmenopausal women were followed 2 years for clinical and estrogen status. 2-min GCF IL-1beta levels averaged from 2 baseline periodontal pockets (in periodontitis subjects) and 2 non-periodontitis sites (in non-periodontitis and periodontitis subjects) were determined with an enzyme immunoassay. A progressive and stable site were also monitored every 6 months for GCF IL-1beta in 15 patients. Results after 2 years indicated that 17 subjects had no posterior interproximal sites losing > or =0.4 mm of alveolar crest bone height, while 13 subjects had > or =3 such sites. Using analysis of variance, none of the above clinical groupings resulted in a significant difference in mean baseline or longitudinal GCF IL-1beta levels. However, when subjects who lost alveolar crest bone height were considered, E2-sufficient subjects had significantly depressed baseline GCF IL-1beta (in past-periodontitis sites) compared to E2-deficient patients (9.1+/-2.1 versus 31.7+/-10.2 pg/2-min sample, p<0.05), suggesting E2 influences gingival IL-1beta production in progressive periodontitis patients.

Biochemical markers of nutrition in osteoporosis

Thirty-six women with vertebral osteoporosis showed significantly decreased levels of biochemical markers of nutrition, transferrin (P < 0.001), prealbumin (P < 0.001), retinol binding-protein (P < 0.001), and fibronectin (P < 0.001), compared with 40 healthy women of similar age. Multiple regression analysis showed a significant (R2 = 0.509; P = 0.0068) correlation between bone mineral content and biochemical markers of nutrition in the osteoporotic patients but not in the control group. These data suggest that postmenopausal osteoporosis may be associated with a nutritional deficiency.

Reduction of risk factors for osteoporosis among adolescents and young adults

Osteoporosis is the most common of all skeletal disorders. The most commonly accepted definition of osteoporosis is a decrease in the amount of calcified bone tissue to the point that fractures occur with minimal trauma. Researchers have shown that peak bone mass at skeletal maturity may be the single most important factor in the development of osteoporosis. At present, no satisfactory way to replace lost bone exists, and the ideal treatment for osteoporosis is prevention, which must begin early in life. The most promising approach in the primary prevention of osteoporosis is to help each person achieve as high a peak skeletal mass and bone density as genetically possible prior to skeletal maturity. Furthermore, identifying those adolescents and young adults at risk is of clinical value for prediction and counseling purposes. Recommendations for achieving the maximal bone mass prior to skeletal maturity, as well as methods of assessing and minimizing the risk factors for osteoporosis, will be discussed.

Crush fracture syndrome in senile osteoporosis: a nutritional consequence?

Osteoporosis is a very important age-related health problem. The body's composition changes with age, and these changes are a true reflection of aging and of the individuals's nutritional status. Mineral content changes have been reported in vertebral osteoporosis. Interestingly, enough, there have not been reports on concomitant water, fat, and fat-free mass changes associated with this condition. In this report, changes in the latter parameters are compared between patients with osteoporosis and controls. The four components (water, mineral, fat, and fat-free mass) were found significantly reduced (p less than 0.001) in osteoporosis. Serum albumin and protein mass were also reduced (p less than 0.001).

Development and evaluation of the Osteoporosis Health Belief Scale

The Osteoporosis Health Belief Scale was developed to measure health beliefs related to osteoporosis. It is a 35-item self-report questionnaire based on the Health Belief Model which is specifically designed to assess beliefs related to exercise behaviors and calcium intake of elderly subjects. The instrument consists of seven subscales: Seriousness, Susceptibility, Health Motivation, Calcium Benefits, Calcium Barriers, Exercise Benefits, and Exercise Barriers. The instrument was tested on a sample of 150 elderly individuals. The psychometric properties of the scales are discussed along with recommendations for its use in research and practice.

Bone mineral density and physical activity in 50-60-year-old women

The bone mineral density (BMD) of the calcaneus was measured utilizing a single energy photon absorption method in 108 women, aged 50-60 years. The women who participated in vigorous exercise two or more times a week or whose total physical activity amounted to 4 h a week had significantly higher BMD values than those who exercised less than two times a week or did less than 4 h physical activity a week. The physically active women also showed higher values for leg extension force and maximal oxygen uptake. BMD and leg extension force were positively correlated, whereas correlations between BMD and body mass, and the width of the calcaneus were negative. When other life-style variables were taken into account, such as smoking and drinking, a significant difference in BMD was found between physically active and sedentary women, but not between the smokers and non-smokers, or the drinkers and non-drinkers.

Structural changes in aging bone: osteopenia in the proximal femurs of female mice

A computerized image analysis system was used to quantitate age-related changes in the structure of the proximal femur in CW-1 female mice, ranging from 3 to 32 months of age. Morphological findings revealed a progressive thinning of bone trabeculae within the femoral head, accompanied by the development of marrow cavities in the cortical bone of the femoral neck and in the subchondral bone. As a result, the compact bone in senescent mice acquired an appearance similar to trabecular bone. Quantitative image analysis revealed a similarity in the pattern of changes in the three types of bone: cortical, trabecular, and subchondral. Bone density increased from 3 to 12 months of age and subsequently declined. A similar pattern was noted for the changes in the thickness of the cortical and the subchondral bone. Regression analysis revealed that the changes with age fitted a second-order model; thus it was possible to predict the age of maximal values for each parameter. Hence, the age of maximal bone density for cortical, trabecular, and subchondral bone was 12.3, 14.8, and 18.0 months, respectively. The rate of bone loss after 12 months was most prominent for trabecular bone (1.47% per month), so that by 32 months of age its overall mass had declined by 57% in comparison to peak values seen at 12 months of age (p less than 0.001). The density of the subchondral and cortical bones decreased at a slower rate (0.6% to 0.8% per month) and at the age of 32 months their values had decreased by 12% to 18% in comparison to those at 12 months (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Osteoporosis: a health issue for women

Osteoporosis is a debilitating disease, most of whose victims are women. This disease results when bone resorption lags behind bone formation, resulting in a net loss of bone. Although the underlying mechanisms have yet to be identified, we know that both aging and decreased estrogen levels promote osteoporosis. The weakened bone is susceptible to fracture and contributes to the morbidity and mortality rates of women over the age of 40. Nonmodifiable risk factors for the development of osteoporosis include being female; having a small, thin body build; and having lighter skin pigmentation. Modifiable risk factors include estrogen and calcium deficiencies, a sedentary lifestyle, smoking, excessive alcohol intake, and certain medical conditions. Restoring estrogen to premenopausal levels results in a slowing of bone loss and maintenance of bone levels for most women for whom estrogen replacement therapy is desirable. Of the treatments available, this one shows the most powerful and protective effect on bone. Because treatment cannot reverse the condition, considerable energy must be directed toward prevention of osteoporosis. Recommendations for prevention have been made on the basis of modifiable risk factors.