Guest guest Posted May 29, 2005 Report Share Posted May 29, 2005 Hi folks: Yes I am still spending time on this! Gradually I think I am getting a better understanding of what it is about. One conclusion I have come to is that one should only pay attention to the results of studies using QCT or MR if one wants to know what is, or is not, truly happening to bone density. The reason is that DXA emphatically does NOT measure DENSITY because it has no idea how big your bones are, and without knowing the volume of the sample it has measured it cannot calculate density/porosity. And volumetric (i.e. true) density is very much more important for bone strength than total quantity of bone. I have yet to find studies that were structured to examine the issues that definitively answer each of the questions I have. But here is an interesting study (PMID: 11748336) conducted on adolescent girls (so it perhaps may not be applicable to older males or females?). It looked at the relationship between " age, body size, puberty, calcium intake, and physical activity " and bone acquisition. The study used QCT so the implications regarding density, and differentiation between trabecular and cortical bone are probably reliable. What did it find? First: none (!!!!!) of the items in the above list of inputs was significantly related to trabecular (osteoporosis-type problem) bone. Second: " Body weight was the most important predictor and determinant of total and cortical bone density and strength " . But note that not even body weight was related to trabecular bone. As we know obese people almost always have high DXA scores, while slim people have low DXA scores. But from the second point above it follows that the higher scores of obese people are the result of greater cortical bone - NOT the result of less porosity! Yet DXA interprets all variations in bone quantity as being variations in porosity in trabecular bone!!! What a joke. Big people have high DXA scores because their extra body weight has provoked their body to supply them with extra cortical bone (i.e. bigger bones, not bones with higher density). Certainly more bone anywhere will help increase bone strength. But it seems to be generally agreed that it is **porosity** - which DXA doesn't measure - in trabecular bone that is the key bone fracture health issue. So, if you have a DXA test and it comes out with a low number your bones may be porous, or they may not be. DXA does not know which. All a low DXA score tells a slim individual is that they have less total bone because they are slim. Or, if yer like, it tells a slim person they are slim. Certainly, if we on CR have less cortical bone because our bones have to support appreciably less weight, then they will be somewhat less strong. But that does not mean they are porous, which is what really matters. What we want to do is to find a way to maximize trabecular bone volumetric density. This study does not tell us how to do that because none of the factors studied were related to it ...... including calcium intake and exercise. It does suggest that weight bearing exercise will increase cortical bone, which will help a little. Whether the standard osteoporosis drugs increase trabecular bone or cortical bone I have yet to determine. If anyone knows of any research that studied that issue (or anything else that is relevant to any of this) please post it. Just another small piece of the puzzle. Alternative interpretations of this study are, of course, welcome. I am still hoping to find a study that shows what factors are most closely related to trabecular bone volumetric density. I have pretty much decided to take no medical interventions in response to my recent lower-than-average (i.e. lower than that of near obese people of same gender and age) DXA score. I do not want to get a QCT bone density test because of the excessive radiation exposure. And I am unlikely to find a place that will administer a good MR bone density test because the machines are very expensive and so far as I know no one does (nor has been trained to do) MR tests for bone density. I will likely be taking more load-bearing exercise. Rodney. Quote Link to comment Share on other sites More sharing options...
Guest guest Posted May 29, 2005 Report Share Posted May 29, 2005 Hi folks: A couple more points: One study, which I believe I posted here a while ago, showed that SWIMMING rats, had better bone density than non-exercising rats. Since swimming does not entail material load- bearing exercise there is some question as to whether it is the bone- loading component of exercise that increases bone mass. I have also read that people with high grip strength have stronger arm bones - even if the grip strength exercise did not include major load bearing - and certainly would not have involved bone compression. This makes one wonder just what the mechanism is by which exercise promotes stronger/larger bones. It might (possibly) be some effect from the muscle contractions necessary for the exercise. The swimming rats were doing plenty of muscle contractions while not supporting a load - indeed a reduced load compared with standing or walking. But still, whatever the mechanism, if it doesn't materially affect *trabecular* bone, then it will not be a major factor in reducing the incidence of fractures. Still lots of unanswered questions here. But not quite as many as there were originally! Rodney. --- In , " Rodney " <perspect1111@y...> wrote: > Hi folks: > > Yes I am still spending time on this! Gradually I think I am getting > a better understanding of what it is about. One conclusion I have > come to is that one should only pay attention to the results of > studies using QCT or MR if one wants to know what is, or is not, > truly happening to bone density. The reason is that DXA emphatically > does NOT measure DENSITY because it has no idea how big your bones > are, and without knowing the volume of the sample it has measured it > cannot calculate density/porosity. And volumetric (i.e. true) > density is very much more important for bone strength than total > quantity of bone. > > I have yet to find studies that were structured to examine the issues > that definitively answer each of the questions I have. > > But here is an interesting study (PMID: 11748336) conducted on > adolescent girls (so it perhaps may not be applicable to older males > or females?). It looked at the relationship between " age, body size, > puberty, calcium intake, and physical activity " and bone > acquisition. The study used QCT so the implications regarding > density, and differentiation between trabecular and cortical bone are > probably reliable. What did it find? > > First: none (!!!!!) of the items in the above list of inputs was > significantly related to trabecular (osteoporosis-type problem) bone. > > Second: " Body weight was the most important predictor and > determinant of total and cortical bone density and strength " . But > note that not even body weight was related to trabecular bone. > > As we know obese people almost always have high DXA scores, while > slim people have low DXA scores. But from the second point above it > follows that the higher scores of obese people are the result of > greater cortical bone - NOT the result of less porosity! Yet DXA > interprets all variations in bone quantity as being variations in > porosity in trabecular bone!!! > > What a joke. > > Big people have high DXA scores because their extra body weight has > provoked their body to supply them with extra cortical bone (i.e. > bigger bones, not bones with higher density). Certainly more bone > anywhere will help increase bone strength. But it seems to be > generally agreed that it is **porosity** - which DXA doesn't measure - > in trabecular bone that is the key bone fracture health issue. > > So, if you have a DXA test and it comes out with a low number your > bones may be porous, or they may not be. DXA does not know which. > All a low DXA score tells a slim individual is that they have less > total bone because they are slim. Or, if yer like, it tells a slim > person they are slim. > > Certainly, if we on CR have less cortical bone because our bones have > to support appreciably less weight, then they will be somewhat less > strong. But that does not mean they are porous, which is what really > matters. > > What we want to do is to find a way to maximize trabecular bone > volumetric density. This study does not tell us how to do that > because none of the factors studied were related to it ...... > including calcium intake and exercise. It does suggest that weight > bearing exercise will increase cortical bone, which will help a > little. Whether the standard osteoporosis drugs increase trabecular > bone or cortical bone I have yet to determine. If anyone knows of > any research that studied that issue (or anything else that is > relevant to any of this) please post it. > > Just another small piece of the puzzle. Alternative interpretations > of this study are, of course, welcome. > > I am still hoping to find a study that shows what factors are most > closely related to trabecular bone volumetric density. > > I have pretty much decided to take no medical interventions in > response to my recent lower-than-average (i.e. lower than that of > near obese people of same gender and age) DXA score. I do not want > to get a QCT bone density test because of the excessive radiation > exposure. And I am unlikely to find a place that will administer a > good MR bone density test because the machines are very expensive and > so far as I know no one does (nor has been trained to do) MR tests > for bone density. I will likely be taking more load-bearing exercise. > > Rodney. 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Guest guest Posted May 30, 2005 Report Share Posted May 30, 2005 Quantitative computed tomography for measuring bone mineral density in athletes. Dinc H, Savci G, Demirci A, Sadikoglu MY, Tuncel E, Yavuz H. KTU Medical School, Department of Radiology, KTU Farabi Hospital, Trabzon 61080, Turkey. We studied the effect of different training patterns on vertebral trabecular and cortical bone mineral density (BMD) in male athletes using quantitative computed tomography. Vertebral trabecular (t) and cortical © BMDs of the first three lumbar vertebrae were measured using single energy quantitative computed tomography in 51 athletes including 10 weight lifters (mean age 20 years), 13 soccer players (mean age 27 years), 28 wrestlers (mean age 17 years), and 45 age-matched volunteers (mean age 21 years). Measured BMDs were correlated with age, body height and weight, training hours per week, sports years, and type of physical activity. Vertebral tBMDs were found to be 44%, 23%, and 24% higher in the weight lifters, soccer players, and wrestlers, respectively, compared with the volunteers. The corresponding cBMDs were 18%, 6%, and 11% higher than that of volunteers. There was significant correlation between the trabecular and cBMD, and height of the athletes, sports years, training hours per week, and physical activity. The most significant correlation with BMD was the type of physical activity. Both the height of the subjects and physical activity variables showed variations of 47% and 32% in trabecular and cBMD, respectively. According to the multiple analysis of variance (MANOVA) only the physical activity factor was effective, with a significance level of P < 0.01; the other factors and interactions were not effective (P > 0.05) on trabecular and cBMD. Different training patterns have a different anabolic effect on both trabecular and cBMDs of the vertebrae, and this effect is more pronounced on the trabecular compartment. Weight lifting showed the highest anabolic effect on both trabecular and cBMDs compared with soccer playing and wrestling. Of the independent variables, physical activity showed the highest anabolic effect on the vertebrae. These results may have implications for devising exercise strategies to reduce the possibility of fracture in old age. > Hi folks: > > Yes I am still spending time on this! Gradually I think I am getting > a better understanding of what it is about. One conclusion I have > come to is that one should only pay attention to the results of > studies using QCT or MR if one wants to know what is, or is not, > truly happening to bone density. The reason is that DXA emphatically > does NOT measure DENSITY because it has no idea how big your bones > are, and without knowing the volume of the sample it has measured it > cannot calculate density/porosity. And volumetric (i.e. true) > density is very much more important for bone strength than total > quantity of bone. > > I have yet to find studies that were structured to examine the issues > that definitively answer each of the questions I have. > > But here is an interesting study (PMID: 11748336) conducted on > adolescent girls (so it perhaps may not be applicable to older males > or females?). It looked at the relationship between " age, body size, > puberty, calcium intake, and physical activity " and bone > acquisition. The study used QCT so the implications regarding > density, and differentiation between trabecular and cortical bone are > probably reliable. What did it find? > > First: none (!!!!!) of the items in the above list of inputs was > significantly related to trabecular (osteoporosis-type problem) bone. > > Second: " Body weight was the most important predictor and > determinant of total and cortical bone density and strength " . But > note that not even body weight was related to trabecular bone. > > As we know obese people almost always have high DXA scores, while > slim people have low DXA scores. But from the second point above it > follows that the higher scores of obese people are the result of > greater cortical bone - NOT the result of less porosity! Yet DXA > interprets all variations in bone quantity as being variations in > porosity in trabecular bone!!! > > What a joke. > > Big people have high DXA scores because their extra body weight has > provoked their body to supply them with extra cortical bone (i.e. > bigger bones, not bones with higher density). Certainly more bone > anywhere will help increase bone strength. But it seems to be > generally agreed that it is **porosity** - which DXA doesn't measure - > in trabecular bone that is the key bone fracture health issue. > > So, if you have a DXA test and it comes out with a low number your > bones may be porous, or they may not be. DXA does not know which. > All a low DXA score tells a slim individual is that they have less > total bone because they are slim. Or, if yer like, it tells a slim > person they are slim. > > Certainly, if we on CR have less cortical bone because our bones have > to support appreciably less weight, then they will be somewhat less > strong. But that does not mean they are porous, which is what really > matters. > > What we want to do is to find a way to maximize trabecular bone > volumetric density. This study does not tell us how to do that > because none of the factors studied were related to it ...... > including calcium intake and exercise. It does suggest that weight > bearing exercise will increase cortical bone, which will help a > little. Whether the standard osteoporosis drugs increase trabecular > bone or cortical bone I have yet to determine. If anyone knows of > any research that studied that issue (or anything else that is > relevant to any of this) please post it. > > Just another small piece of the puzzle. Alternative interpretations > of this study are, of course, welcome. > > I am still hoping to find a study that shows what factors are most > closely related to trabecular bone volumetric density. > > I have pretty much decided to take no medical interventions in > response to my recent lower-than-average (i.e. lower than that of > near obese people of same gender and age) DXA score. I do not want > to get a QCT bone density test because of the excessive radiation > exposure. And I am unlikely to find a place that will administer a > good MR bone density test because the machines are very expensive and > so far as I know no one does (nor has been trained to do) MR tests > for bone density. I will likely be taking more load-bearing exercise. > > Rodney. Quote Link to comment Share on other sites More sharing options...
Guest guest Posted May 30, 2005 Report Share Posted May 30, 2005 Hi : That is great. Thank you. I see the Pubmed ID for that is 8661479. I wish they had included swimmers! I see the same authors also did a QCT study of the overall population (PMID: 8850496). It has some interesting data for rates of bone loss, both cortical and trabecular, with age for both genders. Rodney. > Quantitative computed tomography for measuring bone mineral density in > athletes. > > Dinc H, Savci G, Demirci A, Sadikoglu MY, Tuncel E, Yavuz H. > > KTU Medical School, Department of Radiology, KTU Farabi Hospital, > Trabzon 61080, Turkey. > > We studied the effect of different training patterns on vertebral > trabecular and cortical bone mineral density (BMD) in male athletes > using quantitative computed tomography. Vertebral trabecular (t) and > cortical © BMDs of the first three lumbar vertebrae were measured > using single energy quantitative computed tomography in 51 athletes > including 10 weight lifters (mean age 20 years), 13 soccer players > (mean age 27 years), 28 wrestlers (mean age 17 years), and 45 > age-matched volunteers (mean age 21 years). Measured BMDs were > correlated with age, body height and weight, training hours per week, > sports years, and type of physical activity. Vertebral tBMDs were > found to be 44%, 23%, and 24% higher in the weight lifters, soccer > players, and wrestlers, respectively, compared with the volunteers. > The corresponding cBMDs were 18%, 6%, and 11% higher than that of > volunteers. There was significant correlation between the trabecular > and cBMD, and height of the athletes, sports years, training hours per > week, and physical activity. The most significant correlation with BMD > was the type of physical activity. Both the height of the subjects and > physical activity variables showed variations of 47% and 32% in > trabecular and cBMD, respectively. According to the multiple analysis > of variance (MANOVA) only the physical activity factor was effective, > with a significance level of P < 0.01; the other factors and > interactions were not effective (P > 0.05) on trabecular and cBMD. > Different training patterns have a different anabolic effect on both > trabecular and cBMDs of the vertebrae, and this effect is more > pronounced on the trabecular compartment. Weight lifting showed the > highest anabolic effect on both trabecular and cBMDs compared with > soccer playing and wrestling. Of the independent variables, physical > activity showed the highest anabolic effect on the vertebrae. These > results may have implications for devising exercise strategies to > reduce the possibility of fracture in old age. > > --- In , " Rodney " <perspect1111@y...> wrote: > > Hi folks: > > > > Yes I am still spending time on this! Gradually I think I am getting > > a better understanding of what it is about. One conclusion I have > > come to is that one should only pay attention to the results of > > studies using QCT or MR if one wants to know what is, or is not, > > truly happening to bone density. The reason is that DXA emphatically > > does NOT measure DENSITY because it has no idea how big your bones > > are, and without knowing the volume of the sample it has measured it > > cannot calculate density/porosity. And volumetric (i.e. true) > > density is very much more important for bone strength than total > > quantity of bone. > > > > I have yet to find studies that were structured to examine the issues > > that definitively answer each of the questions I have. > > > > But here is an interesting study (PMID: 11748336) conducted on > > adolescent girls (so it perhaps may not be applicable to older males > > or females?). It looked at the relationship between " age, body size, > > puberty, calcium intake, and physical activity " and bone > > acquisition. The study used QCT so the implications regarding > > density, and differentiation between trabecular and cortical bone are > > probably reliable. What did it find? > > > > First: none (!!!!!) of the items in the above list of inputs was > > significantly related to trabecular (osteoporosis-type problem) bone. > > > > Second: " Body weight was the most important predictor and > > determinant of total and cortical bone density and strength " . But > > note that not even body weight was related to trabecular bone. > > > > As we know obese people almost always have high DXA scores, while > > slim people have low DXA scores. But from the second point above it > > follows that the higher scores of obese people are the result of > > greater cortical bone - NOT the result of less porosity! Yet DXA > > interprets all variations in bone quantity as being variations in > > porosity in trabecular bone!!! > > > > What a joke. > > > > Big people have high DXA scores because their extra body weight has > > provoked their body to supply them with extra cortical bone (i.e. > > bigger bones, not bones with higher density). Certainly more bone > > anywhere will help increase bone strength. But it seems to be > > generally agreed that it is **porosity** - which DXA doesn't measure - > > in trabecular bone that is the key bone fracture health issue. > > > > So, if you have a DXA test and it comes out with a low number your > > bones may be porous, or they may not be. DXA does not know which. > > All a low DXA score tells a slim individual is that they have less > > total bone because they are slim. Or, if yer like, it tells a slim > > person they are slim. > > > > Certainly, if we on CR have less cortical bone because our bones have > > to support appreciably less weight, then they will be somewhat less > > strong. But that does not mean they are porous, which is what really > > matters. > > > > What we want to do is to find a way to maximize trabecular bone > > volumetric density. This study does not tell us how to do that > > because none of the factors studied were related to it ...... > > including calcium intake and exercise. It does suggest that weight > > bearing exercise will increase cortical bone, which will help a > > little. Whether the standard osteoporosis drugs increase trabecular > > bone or cortical bone I have yet to determine. If anyone knows of > > any research that studied that issue (or anything else that is > > relevant to any of this) please post it. > > > > Just another small piece of the puzzle. Alternative interpretations > > of this study are, of course, welcome. > > > > I am still hoping to find a study that shows what factors are most > > closely related to trabecular bone volumetric density. > > > > I have pretty much decided to take no medical interventions in > > response to my recent lower-than-average (i.e. lower than that of > > near obese people of same gender and age) DXA score. I do not want > > to get a QCT bone density test because of the excessive radiation > > exposure. And I am unlikely to find a place that will administer a > > good MR bone density test because the machines are very expensive and > > so far as I know no one does (nor has been trained to do) MR tests > > for bone density. I will likely be taking more load-bearing exercise. > > > > Rodney. Quote Link to comment Share on other sites More sharing options...
Guest guest Posted May 30, 2005 Report Share Posted May 30, 2005 Hi : Quick after thought here. I wonder whether they controlled for BMI when they generated these numbers? " Vertebral tBMDs were found to be 44%, 23%, and 24% higher in the weight lifters, soccer players, and wrestlers, respectively, compared with the volunteers. " Generally, it seems to me, weight lifters have high (sometimes very high) BMIs from higher muscle bulk. So part of that higher tBMD might be accounted for by higher body weights than the soccer players. Soccer players need to be fast on their feet. Something I would not expect of yer average weightlifter! Just a thought. But either way trabecular bone density was increased. Which looks like very good news. I also am curious about the correlation between subjects' height and density. Might this also be because on average taller people weigh more than shorter people? Or was BMI/weight controlled for here too? Rodney. > Quantitative computed tomography for measuring bone mineral density in > athletes. > > Dinc H, Savci G, Demirci A, Sadikoglu MY, Tuncel E, Yavuz H. > > KTU Medical School, Department of Radiology, KTU Farabi Hospital, > Trabzon 61080, Turkey. > > We studied the effect of different training patterns on vertebral > trabecular and cortical bone mineral density (BMD) in male athletes > using quantitative computed tomography. Vertebral trabecular (t) and > cortical © BMDs of the first three lumbar vertebrae were measured > using single energy quantitative computed tomography in 51 athletes > including 10 weight lifters (mean age 20 years), 13 soccer players > (mean age 27 years), 28 wrestlers (mean age 17 years), and 45 > age-matched volunteers (mean age 21 years). Measured BMDs were > correlated with age, body height and weight, training hours per week, > sports years, and type of physical activity. Vertebral tBMDs were > found to be 44%, 23%, and 24% higher in the weight lifters, soccer > players, and wrestlers, respectively, compared with the volunteers. > The corresponding cBMDs were 18%, 6%, and 11% higher than that of > volunteers. There was significant correlation between the trabecular > and cBMD, and height of the athletes, sports years, training hours per > week, and physical activity. The most significant correlation with BMD > was the type of physical activity. Both the height of the subjects and > physical activity variables showed variations of 47% and 32% in > trabecular and cBMD, respectively. According to the multiple analysis > of variance (MANOVA) only the physical activity factor was effective, > with a significance level of P < 0.01; the other factors and > interactions were not effective (P > 0.05) on trabecular and cBMD. > Different training patterns have a different anabolic effect on both > trabecular and cBMDs of the vertebrae, and this effect is more > pronounced on the trabecular compartment. Weight lifting showed the > highest anabolic effect on both trabecular and cBMDs compared with > soccer playing and wrestling. Of the independent variables, physical > activity showed the highest anabolic effect on the vertebrae. These > results may have implications for devising exercise strategies to > reduce the possibility of fracture in old age. > > --- In , " Rodney " <perspect1111@y...> wrote: > > Hi folks: > > > > Yes I am still spending time on this! Gradually I think I am getting > > a better understanding of what it is about. One conclusion I have > > come to is that one should only pay attention to the results of > > studies using QCT or MR if one wants to know what is, or is not, > > truly happening to bone density. The reason is that DXA emphatically > > does NOT measure DENSITY because it has no idea how big your bones > > are, and without knowing the volume of the sample it has measured it > > cannot calculate density/porosity. And volumetric (i.e. true) > > density is very much more important for bone strength than total > > quantity of bone. > > > > I have yet to find studies that were structured to examine the issues > > that definitively answer each of the questions I have. > > > > But here is an interesting study (PMID: 11748336) conducted on > > adolescent girls (so it perhaps may not be applicable to older males > > or females?). It looked at the relationship between " age, body size, > > puberty, calcium intake, and physical activity " and bone > > acquisition. The study used QCT so the implications regarding > > density, and differentiation between trabecular and cortical bone are > > probably reliable. What did it find? > > > > First: none (!!!!!) of the items in the above list of inputs was > > significantly related to trabecular (osteoporosis-type problem) bone. > > > > Second: " Body weight was the most important predictor and > > determinant of total and cortical bone density and strength " . But > > note that not even body weight was related to trabecular bone. > > > > As we know obese people almost always have high DXA scores, while > > slim people have low DXA scores. But from the second point above it > > follows that the higher scores of obese people are the result of > > greater cortical bone - NOT the result of less porosity! Yet DXA > > interprets all variations in bone quantity as being variations in > > porosity in trabecular bone!!! > > > > What a joke. > > > > Big people have high DXA scores because their extra body weight has > > provoked their body to supply them with extra cortical bone (i.e. > > bigger bones, not bones with higher density). Certainly more bone > > anywhere will help increase bone strength. But it seems to be > > generally agreed that it is **porosity** - which DXA doesn't measure - > > in trabecular bone that is the key bone fracture health issue. > > > > So, if you have a DXA test and it comes out with a low number your > > bones may be porous, or they may not be. DXA does not know which. > > All a low DXA score tells a slim individual is that they have less > > total bone because they are slim. Or, if yer like, it tells a slim > > person they are slim. > > > > Certainly, if we on CR have less cortical bone because our bones have > > to support appreciably less weight, then they will be somewhat less > > strong. But that does not mean they are porous, which is what really > > matters. > > > > What we want to do is to find a way to maximize trabecular bone > > volumetric density. This study does not tell us how to do that > > because none of the factors studied were related to it ...... > > including calcium intake and exercise. It does suggest that weight > > bearing exercise will increase cortical bone, which will help a > > little. Whether the standard osteoporosis drugs increase trabecular > > bone or cortical bone I have yet to determine. If anyone knows of > > any research that studied that issue (or anything else that is > > relevant to any of this) please post it. > > > > Just another small piece of the puzzle. Alternative interpretations > > of this study are, of course, welcome. > > > > I am still hoping to find a study that shows what factors are most > > closely related to trabecular bone volumetric density. > > > > I have pretty much decided to take no medical interventions in > > response to my recent lower-than-average (i.e. lower than that of > > near obese people of same gender and age) DXA score. I do not want > > to get a QCT bone density test because of the excessive radiation > > exposure. And I am unlikely to find a place that will administer a > > good MR bone density test because the machines are very expensive and > > so far as I know no one does (nor has been trained to do) MR tests > > for bone density. I will likely be taking more load-bearing exercise. > > > > Rodney. Quote Link to comment Share on other sites More sharing options...
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