3. Acquisition of Bone Mineral Density
Maximal rates of bone mineral accrual lag behind peak height velocity by 6-12 months. Therefore you have relatively undermineralized bone and increased fracture risk in the peripubertal years.
Bone mineral accrual continues after growth is complete but the timing of PBM remains debatable
Maximal rates of bone mineral accrual lag behind peak height velocity by 6-12 months. Therefore you have relatively undermineralized bone and increased fracture risk in the peripubertal years.
Bone mineral accrual continues after growth is complete but the timing of PBM remains debatable
4. Acquisition of Bone Mineral Density
BMD does not correct for bone thickness therefore the volumetric bone mineral might be under estimated in smaller and over estimated in larger individuals.
Data suggests that vertebral size and trabeculae thickness increase while increase in long bone diameter are matched by proportionate increases in cortical thickness but no net increase in volumetric density.
BMD does not correct for bone thickness therefore the volumetric bone mineral might be under estimated in smaller and over estimated in larger individuals.
Data suggests that vertebral size and trabeculae thickness increase while increase in long bone diameter are matched by proportionate increases in cortical thickness but no net increase in volumetric density.
5. Acquisition of Bone Mineral Density
Some investigators feel that decreased bone mass acquisition in early life may not result in decreased PBM
This is supported by what is seen in animal data as well as humans. Children recover from osteoporosis after treatment of Graves disease, JRA, Chronns, lukemia and Cushing syndrome. In these cases remission from disease occurred prior to completion of growth
As juvenile bone enlarges and medullary cavity expands bone formed early in life is gradually resorbed and replaced by new bone through modeling
Schematic diagram representing the replacement of juvenile bone through skeletal growth. As the marrow cavity expands, the juvenile bone (gray) is largely resorbed.
Some investigators feel that decreased bone mass acquisition in early life may not result in decreased PBM
This is supported by what is seen in animal data as well as humans. Children recover from osteoporosis after treatment of Graves disease, JRA, Chronns, lukemia and Cushing syndrome. In these cases remission from disease occurred prior to completion of growth
As juvenile bone enlarges and medullary cavity expands bone formed early in life is gradually resorbed and replaced by new bone through modeling
Schematic diagram representing the replacement of juvenile bone through skeletal growth. As the marrow cavity expands, the juvenile bone (gray) is largely resorbed.
6. Acquisition of Bone Mineral Density
Some studies suggest BMC and BMD are greater in black than in white children before puberty others suggest these differences are not seen until late adolescence. There is limited data from hispanic and asian groups but it suggest that their BMD/BMC is comparable or slightly less than whites and less than blacks.
Osteoporosis Gene: Polymorphisms in the genes encoding the VDR, ER, IGF-1, type 1 collagen, TGF B and IL-6 are currently being investigated. Difficult task because there is likely to be more than one gene in addition to environmental influences causing disease.
Some studies suggest BMC and BMD are greater in black than in white children before puberty others suggest these differences are not seen until late adolescence. There is limited data from hispanic and asian groups but it suggest that their BMD/BMC is comparable or slightly less than whites and less than blacks.
Osteoporosis Gene: Polymorphisms in the genes encoding the VDR, ER, IGF-1, type 1 collagen, TGF B and IL-6 are currently being investigated. Difficult task because there is likely to be more than one gene in addition to environmental influences causing disease.
7. Acquisition of Bone Mineral Density
Epidemiological studies
Table 1: Increase in bone size with added calcium was noted in 2 studies, Response to calcium varied with skelatal site, pretreatment calcium consumption, pubertal stage and genetic factors. (Read through table)
Unknown if short term gains in BMD with supplementation will mean reductions in osteoporosis risk later in life is still unknown.
Non of the studies has continued longer than 3 years nor determined PBM. All but one found the benefits of supplemental calcium stopped once the supplement was stopped
Calcium absorption increases and excretion decreases during adolescence. There is an obligatory loss of 80mg of calcium for every 2300 mg of urinary Na excreted. Adolescence are consuming less dairy and more proceessed food putting them at risk for suboptimal mineral accrual.
Epidemiological studies
Table 1: Increase in bone size with added calcium was noted in 2 studies, Response to calcium varied with skelatal site, pretreatment calcium consumption, pubertal stage and genetic factors. (Read through table)
Unknown if short term gains in BMD with supplementation will mean reductions in osteoporosis risk later in life is still unknown.
Non of the studies has continued longer than 3 years nor determined PBM. All but one found the benefits of supplemental calcium stopped once the supplement was stopped
Calcium absorption increases and excretion decreases during adolescence. There is an obligatory loss of 80mg of calcium for every 2300 mg of urinary Na excreted. Adolescence are consuming less dairy and more proceessed food putting them at risk for suboptimal mineral accrual.
8. Acquisition of Bone Mineral Density
If activity falls below the physiological minimal effective strain threshold, resorption>formation
In the physiologic loading zone bone is maintained
Gain in bone formation when loading is increased.
Children and young adults who participate in intensive weight bearing exercise have significantly greater BMD than their less active controls: Robinson et al found that gymnast have greater BMD than long distance runners.
Interestingly Taafe found that college swimmers had no greater BMD than non athletic controls. Possibly secondary to the weightless state of the pool.
The influence of activity on bone modeling and mineral accrual is greater before and during puberty than later in adulthood
Increased bone mineral acquired with early intensive activity persists in adulthood.
If activity falls below the physiological minimal effective strain threshold, resorption>formation
In the physiologic loading zone bone is maintained
Gain in bone formation when loading is increased.
Children and young adults who participate in intensive weight bearing exercise have significantly greater BMD than their less active controls: Robinson et al found that gymnast have greater BMD than long distance runners.
Interestingly Taafe found that college swimmers had no greater BMD than non athletic controls. Possibly secondary to the weightless state of the pool.
The influence of activity on bone modeling and mineral accrual is greater before and during puberty than later in adulthood
Increased bone mineral acquired with early intensive activity persists in adulthood.
9. Acquisition of Bone Mineral Density
Table 2:Contribution of moderate physical exercise to bone mineral acquisition is less well established: Controlled activity trials have only continued for 5-10 months and it is unknown if the effects will continue
Optimal response to activity appears to require optimal calcium intake as well. One study showed that increrased activity had a positive effect on BMD only in the presence of greater than 1000mg/calcium/day
Table 2:Contribution of moderate physical exercise to bone mineral acquisition is less well established: Controlled activity trials have only continued for 5-10 months and it is unknown if the effects will continue
Optimal response to activity appears to require optimal calcium intake as well. One study showed that increrased activity had a positive effect on BMD only in the presence of greater than 1000mg/calcium/day
10. Acquisition of Bone Mineral Density
GHD: reduced BMD which can only partly be explained by reduced bone size and delayed skeletal maturation
Delayed puberty has been thought to be responsible for reduced PBM but subsequent studies found that normal PBM is achieved eventually whether or not sex steroid treatment was used to initiate treatment.
GHD: reduced BMD which can only partly be explained by reduced bone size and delayed skeletal maturation
Delayed puberty has been thought to be responsible for reduced PBM but subsequent studies found that normal PBM is achieved eventually whether or not sex steroid treatment was used to initiate treatment.
13. Over Diagnosis of Osteoporosis in Children
The most frequent error was the use of a T score to diagnose osteoporosis.
Second most frequent error was the use of an inappropriate data base. For example not differentiating between boys and girls. This may be alright in younger children but in peri and pubertal children can lead to error
Errors in bone mapping was seen in 21% of scans
Errors in correcting for height age or short stature
The most frequent error was the use of a T score to diagnose osteoporosis.
Second most frequent error was the use of an inappropriate data base. For example not differentiating between boys and girls. This may be alright in younger children but in peri and pubertal children can lead to error
Errors in bone mapping was seen in 21% of scans
Errors in correcting for height age or short stature
17. Use of Bisphosphonates for Osteoporosis in Children
May have permanent skelatal damage
Since the disease remits on its own judicious use of bisphosphonates should be carefully considered.
May have permanent skelatal damage
Since the disease remits on its own judicious use of bisphosphonates should be carefully considered.
19. Use of Bisphosponates for Osteoporosis in Children
Pamidronate: symptomatic and not curative
No clear how long treatment should be continued, optimal treatment schedule and if other bisphosphonates have a similar or better clinical outcome.
Pamidronate: symptomatic and not curative
No clear how long treatment should be continued, optimal treatment schedule and if other bisphosphonates have a similar or better clinical outcome.
20. Use of Bisphosponates for Osteoporosis in Children
There is conflicting data as to what role pamidronate plays at the site of old lesions and progression of new lesions.
There is conflicting data as to what role pamidronate plays at the site of old lesions and progression of new lesions.
21. Use of Bisphosphonates for Osteoporosis in Children
Normalize calcium in 2-5 days
Repeat the dose of pamidronate in a week
Normalize calcium in 2-5 days
Repeat the dose of pamidronate in a week
22. Use of Bisphosphonates for Osteoporosis in Children
1. Can also see a transient drop in lyphocyte count.
Fracture Healing: One study showed that fracture healing was not delayed and there was not evidence of fracture non-union in children with OI treated with bisphosphonates.
Growth: Gloriuex found in her OI patients that the growth plate was not changed and bone ages corresponded to chronological ages.
It has been observed that there is sclerosis at the metaphysis of long bones and in vertabrae when given to patients with open epiphysis: This is from the increase in bone formation in addition to the high levels of osteoblastic activity near the growth plates. There is a gradual decrease in the lines if treament is stopped.
1. Can also see a transient drop in lyphocyte count.
Fracture Healing: One study showed that fracture healing was not delayed and there was not evidence of fracture non-union in children with OI treated with bisphosphonates.
Growth: Gloriuex found in her OI patients that the growth plate was not changed and bone ages corresponded to chronological ages.
It has been observed that there is sclerosis at the metaphysis of long bones and in vertabrae when given to patients with open epiphysis: This is from the increase in bone formation in addition to the high levels of osteoblastic activity near the growth plates. There is a gradual decrease in the lines if treament is stopped.
23. Use of Bisphosponates for Osteoporosis in Children
Humans: 2 pregnant women given iv pamindronate in the third trimester for metastatic breast cancer with no adverse outcome.
When to use bisphophonates: Symptomatic osteoporosis should be considered. Children should be part of a clinical trial if possible.
Humans: 2 pregnant women given iv pamindronate in the third trimester for metastatic breast cancer with no adverse outcome.
When to use bisphophonates: Symptomatic osteoporosis should be considered. Children should be part of a clinical trial if possible.