Study of Fall and Fracture Risk in Menopausal Women Living in Urban Areas for the Prevention of Osteoporotic Fractures

The purpose of this study was to clarify whether preventive measures against falling, which leads to bone fractures, should be started in the senile stage or peri-menopausal period, when the bone mass decreases markedly. In a total of 395 females aged 45, 50, 55, 60, and 65, we measured bone density of the lumbar spine by DXA, calcaneus bone density by SXA, and they answered a questionnaire regarding their health status during a medical check-up at their public health care center. We conducted a questionnaire survey by mail 2 years after the check-up, and investigated their experiences of falling and bone fractures and the situation in which these incidents happened, and analyzed the occurrence of falling and bone fractures in menopausal women and associated factors. (The number of subjects involved in the analysis was 265.) A total of 23% experienced falls, 3.4% (9 people) occured fractures over the period of 2 years, and no significant difference was noted among the ages. Most falls occurred outdoors, on steps while they were walking. The reasons for falling were mostly related to external factors, such as slipping and tripping. The risk factors associated with falling for menopausal women were a high BMI and body fat percentage, weak grip strength. These results suggest that the prevention of falling in the menopausal period is essential, and that maintaining an appropriate physique and improving bone density and body strength are important measures. It was suggested that the promotion of concrete measures against falling not only for the elderly but also for menopausal women is essential

Hydrolyzed collagen intake increases bone mass of growing rats trained with running exercise

BackgroundSome studies have shown that dietary hydrolyzed collagen peptides (HC) effectively prevent age-related bone loss. However, it is not known whether the intake of HC also has positive effect on bone mass or strength when combined with exercise during growth phase.MethodsWe examined the effects of 11 weeks of HC intake and running exercise on bone mass and strength in growing rats. Rats were randomized into four groups, the 20% casein group (Casein20), the 40% casein group (Casein40), the 20% HC group (HC20), and the 40% HC group (HC40). Each group was further divided into exercise groups (Casein20 + Ex, Casein40 + Ex, HC20 + Ex, HC40 + Ex) and non-exercise group (Casein20, Casein40, HC20, HC40). In the HC intake groups, 30% of casein protein was replaced with HC. Exercise group rats were trained 6 days per week on a treadmill (25–30 m/min, 60 min) for 60 days. After being sacrificed, their bone mineral content (BMC) and bone strength were evaluated.ResultsExercise and dietary HC effects were observed in the adjusted BMC of lumbar spine and tibia among the 20% protein groups (p < 0.001 for exercise; p < 0.05 for dietary HC, respectively). These effects were also noted in the adjusted wet weight and dry weight of femur among the 20% protein groups (p < 0.001, p < 0.01 for exercise; p < 0.01, p < 0.001 for dietary HC, respectively). On the other hand, in adjusted bone breaking force and energy, dietary HC effect was not significant. Among the 40% protein groups, similar results were obtained in the adjusted BMC, femoral weight, bone breaking force, and energy. There were no differences between the 20% protein groups and the 40% protein groups.ConclusionsThe present study demonstrated that moderate HC intake (where the diet contains 20% protein, of which 30% is HC) increased bone mass during growth period and further promoted the effect of running exercise. On the other hand, a higher HC intake (where the diet contains 40% protein, of which 30% is HC) had no more beneficial effect on bone mass than the moderate HC intake

Estrogen deficiency and low-calcium diet increased bone loss and urinary calcium excretion but did not alter arterial stiffness in young female rats

Many epidemiological studies have reported that the severity of arterial diseases such as arterial calcification and stiffness is inversely related to bone loss, i.e., osteoporosis. However, the nature of this relationship is unclear. The purpose of the present study was to examine the influences of estrogen deficiency and/or low-calcium diet (0.1% Ca) on bone metabolism and calcium balance, as well as aortic wall composition and stiffness in young female rats. Twenty-eight 6-week-old female rats were randomized into four groups: OVX-Low calcium (OL) and OVX-Normal calcium groups (ON) were ovariectomized, and Sham-Low calcium (SL) and Sham-Normal calcium groups (SN) were sham-operated. After 12 weeks, the bone mineral density of the lumbar spine and tibial proximal metaphysis were significantly lower in ON than in SN, and also significantly lower in OL than in ON. Additionally, OL rats had significant higher (vs. SN and SL) urinary deoxypyridinoline, but not urinary calcium, excretion at 4 weeks after ovariectomy. However, at 12 weeks after ovariectomy, urinary calcium excretion was significantly higher in OL than in SL, with corresponding increases in two bone turnover markers, bone-type alkaline phosphatase and tartrate-resistant acid phosphatase. Neither estrogen deficiency nor low-calcium diet affected aortic stiffness or elastin degeneration and calcium deposition over the course of the present study, although changes of bone metabolism occurred rapidly. Taken together, these results show that bone loss and arterial stiffness did not progress simultaneously in the present experimental protocol

DHEA Administration Activates Local Bioactive Androgen Metabolism in Cancellous Site of Tibia of Ovariectomized Rats

It is not known whether local androgen metabolism is involved in the mechanisms underlying the dehydroepiandrosterone (DHEA) administration-induced improvement of bone mineral density (BMD) in an estrogen-deficiency state. The aim of the present study was to clarify whether DHEA administration would improve local androgen metabolism and BMD in cancellous site of tibia of ovariectomized (OVX) rats. Twenty-two female rats, 6 weeks old, were randomized into three groups: sham-operated rats, OVX control rats, and OVX rats that received DHEA treatment. DHEA was administered intraperitoneally at 20 mg/kg body weight for 8 weeks. The concentrations of free testosterone and dihydrotestosterone (DHT) in cancellous site of tibia did not change as a result of ovariectomy, while the DHT concentration increased following DHEA administration. We revealed that DHEA administration improved the reduction of 17β- and 3β-hydroxysteroid dehydrogenases and clearly reversed the reduction of 5α-reductase types 1 and 2 and androgen receptor in the cancellous site of tibia of OVX rats. DHEA administration suppressed estrogen deficiency relative to the decrease in the cancellous BMD, which was positively associated with local DHT concentration. These findings indicate that DHEA administration enhances local bioactive androgen metabolism in the cancellous tibia of young OVX rats, suggesting that local DHT may play a part in the DHEA administration-induced improvement of cancellous BMD

VOLUNTARY EXERCISE INCREASES OSTEOGENETIC ACTIVITY IN RAT BONES

The purpose of this study was to investigate the effect of voluntary exercise on osteoinductive activity in rat bone. Sprague-Dawley male and female rats were allowed to exercise freely by running on a treadmill or kept as controls without exercise for 53 days. Decalcified humeral diaphyses from experimental and control rats were implanted intraperitonealy into host rats and harvested after 33 days. A significant increase in bone formation was confirmed in the implanted bone matrices from the running group in comparison with those from control animals by soft X-ray photography and determination of alkaline phosphatase activity and mineral content. Alkaline phosphatase activity in bone and serum was increased by exercise in both male and female animals. The results suggest that osteoinductive activity in the bone was probably due to increased levels of bone morphogenetic protein following voluntary exercise