- Email: [email protected]
Vitamin D receptor genotypes and bone mineral density
Vitamin D receptor genotypes and bone mineral density SiR-Ferrari and colleagues (Feb 18, p 423) report that vitamin D receptor (VDR) gene allelic polymorphism is associated with the rate of bone loss in elderly subjects. Common allelic variants in the gene encoding the VDR are determinants of serum osteocalcin and bone mineral density (BMD).’ Thus, genotyping could be used to predict an individual’s risk of osteoporosis. However, there are substantial racial differences in genotype frequencies of the VDR polymorphism, and not all studies have confirmed the relation between the VDR polymorphism and serum osteocalcin or BMD.23 We have investigated whether VDR genotypes can predict change of bone mineral density and bone turnover assessed by serum markers in a populationbased sample of early postmenopausal women, whose genetic background differs from the populations studied
previously. 28 postmenopausal women were randomly drawn from the population-based study population of the Kuopio osteoporosis study.’ However, the analyses were restricted to the 23 women who had never used hormone replacement therapy (HRT). DNA was isolated from whole blood, PCR was used to amplify the DNA sequence, and the Bsm 1 (New England Biolabs, MA, USA) restriction enzyme was used to detect VDR alleles.’ Serum osteocalcin (CIS Bio International, Gif-Sur-Yvette Cedex, France), carboxylterminal pyridinoline cross-linked telopeptide of type I collagen (ICTP), and carboxylterminal propeptide of type I collagen (PICP) (Orion Diagnostica, Oulu, Finland) concentrations were measured by radioimmunoassay as recommended by the supplier. Furthermore, serum bonespecific alkaline phosphatase (BAP), serum 25hydroxyvitamin-D (25-OH-D) and 1,25-dihydroxyvitaminD (1,25[OH12D3) were measured. BMD was measured twice (mean [SD] interval 2-8 [0-4] years) with dual energy X-ray absorptiometry (Lunar DPX, Madison, WI) at the spine (L2-L4) and left femoral neck. The reproducibility of dual energy X-ray absorptiometry in our hospital is 0-9% for spine and 1-5% for femoral neck measurements. No patient had signs of vertebral fractures (loss of vertebral height after the first measurement) on scanning. The relative frequencies of the VDR genotypes among the 28 postmenopausal women were: BB 7-1%, Bb 57-2%, bb 35-7%. Age (mean [SD] 52-5 [2’0] years), weight (67-7 [9’5] kg), height (160 [5] cm), or years since menopause (1-4 [0.4] years) did not differ between the VDR genotype groups. By contrast with Ferrari and colleagues’ findings, baseline BMD and annual change of BMD did not differ between the VDR genotype groups (table). Mean serum
Means (SD) shown. NS=not significant. S=serum. *Analysis ofvanance. Table: Serum markers of bone metabolism, BMD data, and VDR genotype in postmenopausal women without HRT
1238
osteocalcin and serum ICTP (a suggested marker of bone resorption) were highest in the bb genotype group, indicating increased bone turnover in this group. Although the number of subjects was small, our results contradict those of most previous reports, and it seems that VDR allelic variation has limited clinical importance in predicting change of BMD or bone turnover in Finnish
postmenopausal women. *H Kröger, A Mahonen, S P Mäenpää
Ryhänen, A-M Turunen, E Alhava,
*Department of Surgery, Kuopio University Hospital, FIN-70210 Kuopio, Finland; and Department of Biochemistry and Biotechnology, University of Kuopio
1 2
3 4
Morrison NA, Qi CJ, Tokita A, et al. Prediction of bone mineral density from vitamin D receptor alleles. Nature 1994; 367: 284-87. Hustmyer FG, Peacock M, Hui S, Johnston CC, Christian JC. Bone mineral density in relation to polymorphism at the vitamin D receptor gene locus. J Clin Invest 1994; 94: 2130-34. Melhus H, Kindmark A, Amer S, Wilen B, Lindh E, Ljunghall S. Vitamin D receptor genotypes in osteoporosis. Lancet 1994; 344: 1581. Kröger H, Huopio J, Honkanen R, et al. Prediction of fracture risk using axial bone mineral density in a perimenopausal population—a prospective study. J Bone Miner Res 1995; 10: 302-06.
reports an association between VDR polymorphisms, which contribute to the genetic variation in bone turnover and density,’-’ and rate of lumbar-spine bone loss in the elderly. We have examined the effect of lahydroxy vitamin D3 (1 pg per day) treatment with calcium SiR-Ferrari
mg per day) on lumbar-spine BMD least 12 months (duration of therapy, 2-0 [SD 09] years). We investigated 120 osteoporotic (primary 96, secondary 24) women (age 67-8 [9’7]) in respect of VDR polymorphisms. BMD was measured in the lumbar spine (L2-L4) with dual energy X-ray absorptiometry (Norland XR-26). DNA analysis was done with PCR as previously reported2 at the Department of Paediatrics, Juntendo University, and Mitsubishi Kagaku BCL, Tokyo, blind to clinical data. As noted by Yamagata and co-workers,3 BMD is affected by VDR genotype in Japanese subjects, but with
supplementation (400 over at
Figure: Rate of change of lumbar-spine (LS) bone density after la-hydroxy vitamin D3 therapy Overall p=0008.
different allele frequencies from those in caucasian subjects. We found only two BB homozygotes in this population. However, further analysis of genotype with multiple
If such a difference were maintained over several years, it would result in a substantially different risk of hip fracture between the homozygotes, in accord with Morrison and colleagues’ predictions. The data presented by Matsuyama and colleagues show that supplementation of vitamin D and low-dose oral calcium (400 mg per day) was associated with a positive rate of change in lumbar-spine BMD in bb elderly Japanese women, whereas it did not prevent bone loss in Bb heterozygotes. These results fully accord with our own observations, suggesting that VDR gene polymorphism defines an important subgroup of elderly patients (Bb) requiring larger amounts of calcium to prevent lumbar-spine bone loss. These studies lend support to the contention that VDR gene polymorphism is associated with different rates of BMD change in individuals with good vitamin D status. Such an association might be especially relevant in the management of elderly patients.
respectively).
restriction-fragment-length polymorphisms (Bsm I, Apa I, Taq I) resulted in four frequent genotypes (bbaaTT, bbAaTT, BbAaTt, BbAATt). ANOVA analysis of the BMD traits of these genotypes suggested an almost linear effect of genotype on lumbar-spine bone density in premenopausal Japanese women (unpublished). The women with these four VDR genotype groups were similar in terms of age, height, weight, and duration of la-hydroxy vitamin D3treatment. However, VDR genotype was associated with the rate of change of lumbar-spine bone density after la-hydroxy vitamin D3 treatment (figure). In particular, the more common genotypes (bbaaTT and bbAaTT, 75% of were associated with a positive response to lasubjects) vitamin hydroxy D3 therapy. By contrast, the poor response in the genotype BbAaTt, the most common in caucasians, could account for the generally good responses to active vitamin D analogues recorded in Japanese compared with North American subjects. Analysis of VDR alleles may prove useful in selection of optimum dose of active vitamin D therapy for osteoporosis or optimum therapy for osteoporosis management.
*S L Ferrari, R Rizzoli, T Division of Clinical
Riggs BL, Melton III LJ. Involution osteoporosis. N Engl J Med 1986; 314: 1676-86. Morrison NA, Qi JC, Tokita A, et al. Prediction of bone density from vitamin D receptor alleles. Nature 1994; 367: 284-87.
1 2
Keijiro Yabuta, Shunji Yamamori, Nigel A Morrison, John A Eisman Department of Orthopaedics, Sapporo Medical School, Hokkaido; *Department of Paediatrics, Juntendo University School of Medicine, Tokyo 113, Japan; Gene Analysis Division, Mitsubishi Kagaku BCL, Tokyo; and Bone and Mineral Research Division, Garvan Institute of Medical Research, St Vincent’s Hospital, Sydney, Australia
Demarcation of ulcerative colitis SiR-Hamilton and colleagues (March 18, p 688) ask the interesting question "Is proximal demarcation of ulcerative colitis determined by the territory of the inferior mesenteric artery?". The answer cannot be provided by examination of three colectomy specimens, nor indeed do these workers
1 Morrison NA, Yeoman R, Kelly PJ, et al. Contribution of trans-acting factor alleles to normal physiological variability: vitamin D receptor gene polymorphisms and circulating osteocalcin. Proc Natl Acad Sci USA 1992; 89: 6665-69. 2 Morrison NA, Qi JC, Tokita A, et al. Prediction of bone density from vitamin D receptor alleles. Nature 1994; 367: 284-87. 3 Yamagata Z, Miyamura T, Iijima S, et al. Vitamin D receptor gene polymorphism and bone mineral density in healthy Japanese women. Lancet 1994; 344: 1027.
reply their
study in 195 early Keen and postmenopausal women, colleagues (April 15, p 990) conclude that the absence of an association between VDR gene polymorphism and the rate of change in bone mineral density (BMD) from the hip or the spine was in contrast with our findings (Feb 18, p 423). However, the two cohorts studied differed strikingly: we investigated SiR-From
longitudinal
vitamin-D-replete, calcium-supplemented elderly patients,
Bonjour
University Hospital of Geneva, 1211 Geneva 14, Switzerland
Toshikatsu Matsuyama, Seiichi Ishii, *Akifumi Tokita,
Authors’
Chevalley, J Eisman, J-P Pathophysiology, Department of Medicine,
a
third of whom had femoral neck fractures, whereas Keen and co-workers studied early postmenopausal women. The apparent discrepancy in the results between the two studies could thus be related to the prominent part played by the vitamin D endocrine system in the pathophysiology of senile osteoporosis,’ whereas oestrogen deprivation is the major cause of accelerated bone loss soon after the menopause. The group studied could also account for Kroger and colleagues’ negative results. Moreover, the very small number of BB subjects (n=2) prevents any conclusion being drawn for this particular genotype. On the other hand, comparison of Keen and co-workers’ findings with those of Morrison and colleagues,2 who suggested that the rate of bone loss after the menopause was higher in BB subjects, is of interest. Keen’s data show a higher annual rate of bone loss at the femoral neck in tt (BB) than in TT (bb) subjects (-1-00 vs -0-48% per year,
make such a claim. The marginal artery of the colon is most frequently deficient at the region of the splenic flexure, as seems to be the case in their figure 2; this is why ischaemic colitis, a condition quite different clinically, radiologically, and histologically from ulcerative colitis, is most frequently seen at that point.1,2 Of course, absence of the marginal artery does not itself imply deficient blood flow, because the submucosal plexus can often provide a complete anastomotic network, but this is clearly not so in the arteriogram shown in figure 3. Hamilton and colleagues are careful not to suggest that the changes seen in ulcerative colitis are dependent on something as simple as a deficient blood supply, and speculate on the role of neural and genetic factors. It would also be interesting to know whether or not the mucosal blood flow in this area was normal, and this is now easily measured by means of an intraluminal tonometer. Whereabouts in the colon does ulcerative colitis usually stop? My impression is that the commonest proximal demarcation point is at the rectosigmoid, or half way along the transverse colon, rather than at the splenic flexure. There must be some clear-cut information on this point, and I would be interested to hear of the experience of other clinicians. Adrian Marston Private Consulting Rooms, Woolavington Wing,
Middlesex
Hospital,
London W1 8AA, UK
1 2
Marston A, Pheils MT, Thomas ML, Morson BC. Ischaemic colitis. Gut 1966; 7: 1. Marston A. Ischaemia of the gut. In: Pounder, Misciewicz, eds. Diseases of the gut and pancreas. London: Blackwell Scientific, 1987.
1239
previously. 28 postmenopausal women were randomly drawn from the population-based study population of the Kuopio osteoporosis study.’ However, the analyses were restricted to the 23 women who had never used hormone replacement therapy (HRT). DNA was isolated from whole blood, PCR was used to amplify the DNA sequence, and the Bsm 1 (New England Biolabs, MA, USA) restriction enzyme was used to detect VDR alleles.’ Serum osteocalcin (CIS Bio International, Gif-Sur-Yvette Cedex, France), carboxylterminal pyridinoline cross-linked telopeptide of type I collagen (ICTP), and carboxylterminal propeptide of type I collagen (PICP) (Orion Diagnostica, Oulu, Finland) concentrations were measured by radioimmunoassay as recommended by the supplier. Furthermore, serum bonespecific alkaline phosphatase (BAP), serum 25hydroxyvitamin-D (25-OH-D) and 1,25-dihydroxyvitaminD (1,25[OH12D3) were measured. BMD was measured twice (mean [SD] interval 2-8 [0-4] years) with dual energy X-ray absorptiometry (Lunar DPX, Madison, WI) at the spine (L2-L4) and left femoral neck. The reproducibility of dual energy X-ray absorptiometry in our hospital is 0-9% for spine and 1-5% for femoral neck measurements. No patient had signs of vertebral fractures (loss of vertebral height after the first measurement) on scanning. The relative frequencies of the VDR genotypes among the 28 postmenopausal women were: BB 7-1%, Bb 57-2%, bb 35-7%. Age (mean [SD] 52-5 [2’0] years), weight (67-7 [9’5] kg), height (160 [5] cm), or years since menopause (1-4 [0.4] years) did not differ between the VDR genotype groups. By contrast with Ferrari and colleagues’ findings, baseline BMD and annual change of BMD did not differ between the VDR genotype groups (table). Mean serum
Means (SD) shown. NS=not significant. S=serum. *Analysis ofvanance. Table: Serum markers of bone metabolism, BMD data, and VDR genotype in postmenopausal women without HRT
1238
osteocalcin and serum ICTP (a suggested marker of bone resorption) were highest in the bb genotype group, indicating increased bone turnover in this group. Although the number of subjects was small, our results contradict those of most previous reports, and it seems that VDR allelic variation has limited clinical importance in predicting change of BMD or bone turnover in Finnish
postmenopausal women. *H Kröger, A Mahonen, S P Mäenpää
Ryhänen, A-M Turunen, E Alhava,
*Department of Surgery, Kuopio University Hospital, FIN-70210 Kuopio, Finland; and Department of Biochemistry and Biotechnology, University of Kuopio
1 2
3 4
Morrison NA, Qi CJ, Tokita A, et al. Prediction of bone mineral density from vitamin D receptor alleles. Nature 1994; 367: 284-87. Hustmyer FG, Peacock M, Hui S, Johnston CC, Christian JC. Bone mineral density in relation to polymorphism at the vitamin D receptor gene locus. J Clin Invest 1994; 94: 2130-34. Melhus H, Kindmark A, Amer S, Wilen B, Lindh E, Ljunghall S. Vitamin D receptor genotypes in osteoporosis. Lancet 1994; 344: 1581. Kröger H, Huopio J, Honkanen R, et al. Prediction of fracture risk using axial bone mineral density in a perimenopausal population—a prospective study. J Bone Miner Res 1995; 10: 302-06.
reports an association between VDR polymorphisms, which contribute to the genetic variation in bone turnover and density,’-’ and rate of lumbar-spine bone loss in the elderly. We have examined the effect of lahydroxy vitamin D3 (1 pg per day) treatment with calcium SiR-Ferrari
mg per day) on lumbar-spine BMD least 12 months (duration of therapy, 2-0 [SD 09] years). We investigated 120 osteoporotic (primary 96, secondary 24) women (age 67-8 [9’7]) in respect of VDR polymorphisms. BMD was measured in the lumbar spine (L2-L4) with dual energy X-ray absorptiometry (Norland XR-26). DNA analysis was done with PCR as previously reported2 at the Department of Paediatrics, Juntendo University, and Mitsubishi Kagaku BCL, Tokyo, blind to clinical data. As noted by Yamagata and co-workers,3 BMD is affected by VDR genotype in Japanese subjects, but with
supplementation (400 over at
Figure: Rate of change of lumbar-spine (LS) bone density after la-hydroxy vitamin D3 therapy Overall p=0008.
different allele frequencies from those in caucasian subjects. We found only two BB homozygotes in this population. However, further analysis of genotype with multiple
If such a difference were maintained over several years, it would result in a substantially different risk of hip fracture between the homozygotes, in accord with Morrison and colleagues’ predictions. The data presented by Matsuyama and colleagues show that supplementation of vitamin D and low-dose oral calcium (400 mg per day) was associated with a positive rate of change in lumbar-spine BMD in bb elderly Japanese women, whereas it did not prevent bone loss in Bb heterozygotes. These results fully accord with our own observations, suggesting that VDR gene polymorphism defines an important subgroup of elderly patients (Bb) requiring larger amounts of calcium to prevent lumbar-spine bone loss. These studies lend support to the contention that VDR gene polymorphism is associated with different rates of BMD change in individuals with good vitamin D status. Such an association might be especially relevant in the management of elderly patients.
respectively).
restriction-fragment-length polymorphisms (Bsm I, Apa I, Taq I) resulted in four frequent genotypes (bbaaTT, bbAaTT, BbAaTt, BbAATt). ANOVA analysis of the BMD traits of these genotypes suggested an almost linear effect of genotype on lumbar-spine bone density in premenopausal Japanese women (unpublished). The women with these four VDR genotype groups were similar in terms of age, height, weight, and duration of la-hydroxy vitamin D3treatment. However, VDR genotype was associated with the rate of change of lumbar-spine bone density after la-hydroxy vitamin D3 treatment (figure). In particular, the more common genotypes (bbaaTT and bbAaTT, 75% of were associated with a positive response to lasubjects) vitamin hydroxy D3 therapy. By contrast, the poor response in the genotype BbAaTt, the most common in caucasians, could account for the generally good responses to active vitamin D analogues recorded in Japanese compared with North American subjects. Analysis of VDR alleles may prove useful in selection of optimum dose of active vitamin D therapy for osteoporosis or optimum therapy for osteoporosis management.
*S L Ferrari, R Rizzoli, T Division of Clinical
Riggs BL, Melton III LJ. Involution osteoporosis. N Engl J Med 1986; 314: 1676-86. Morrison NA, Qi JC, Tokita A, et al. Prediction of bone density from vitamin D receptor alleles. Nature 1994; 367: 284-87.
1 2
Keijiro Yabuta, Shunji Yamamori, Nigel A Morrison, John A Eisman Department of Orthopaedics, Sapporo Medical School, Hokkaido; *Department of Paediatrics, Juntendo University School of Medicine, Tokyo 113, Japan; Gene Analysis Division, Mitsubishi Kagaku BCL, Tokyo; and Bone and Mineral Research Division, Garvan Institute of Medical Research, St Vincent’s Hospital, Sydney, Australia
Demarcation of ulcerative colitis SiR-Hamilton and colleagues (March 18, p 688) ask the interesting question "Is proximal demarcation of ulcerative colitis determined by the territory of the inferior mesenteric artery?". The answer cannot be provided by examination of three colectomy specimens, nor indeed do these workers
1 Morrison NA, Yeoman R, Kelly PJ, et al. Contribution of trans-acting factor alleles to normal physiological variability: vitamin D receptor gene polymorphisms and circulating osteocalcin. Proc Natl Acad Sci USA 1992; 89: 6665-69. 2 Morrison NA, Qi JC, Tokita A, et al. Prediction of bone density from vitamin D receptor alleles. Nature 1994; 367: 284-87. 3 Yamagata Z, Miyamura T, Iijima S, et al. Vitamin D receptor gene polymorphism and bone mineral density in healthy Japanese women. Lancet 1994; 344: 1027.
reply their
study in 195 early Keen and postmenopausal women, colleagues (April 15, p 990) conclude that the absence of an association between VDR gene polymorphism and the rate of change in bone mineral density (BMD) from the hip or the spine was in contrast with our findings (Feb 18, p 423). However, the two cohorts studied differed strikingly: we investigated SiR-From
longitudinal
vitamin-D-replete, calcium-supplemented elderly patients,
Bonjour
University Hospital of Geneva, 1211 Geneva 14, Switzerland
Toshikatsu Matsuyama, Seiichi Ishii, *Akifumi Tokita,
Authors’
Chevalley, J Eisman, J-P Pathophysiology, Department of Medicine,
a
third of whom had femoral neck fractures, whereas Keen and co-workers studied early postmenopausal women. The apparent discrepancy in the results between the two studies could thus be related to the prominent part played by the vitamin D endocrine system in the pathophysiology of senile osteoporosis,’ whereas oestrogen deprivation is the major cause of accelerated bone loss soon after the menopause. The group studied could also account for Kroger and colleagues’ negative results. Moreover, the very small number of BB subjects (n=2) prevents any conclusion being drawn for this particular genotype. On the other hand, comparison of Keen and co-workers’ findings with those of Morrison and colleagues,2 who suggested that the rate of bone loss after the menopause was higher in BB subjects, is of interest. Keen’s data show a higher annual rate of bone loss at the femoral neck in tt (BB) than in TT (bb) subjects (-1-00 vs -0-48% per year,
make such a claim. The marginal artery of the colon is most frequently deficient at the region of the splenic flexure, as seems to be the case in their figure 2; this is why ischaemic colitis, a condition quite different clinically, radiologically, and histologically from ulcerative colitis, is most frequently seen at that point.1,2 Of course, absence of the marginal artery does not itself imply deficient blood flow, because the submucosal plexus can often provide a complete anastomotic network, but this is clearly not so in the arteriogram shown in figure 3. Hamilton and colleagues are careful not to suggest that the changes seen in ulcerative colitis are dependent on something as simple as a deficient blood supply, and speculate on the role of neural and genetic factors. It would also be interesting to know whether or not the mucosal blood flow in this area was normal, and this is now easily measured by means of an intraluminal tonometer. Whereabouts in the colon does ulcerative colitis usually stop? My impression is that the commonest proximal demarcation point is at the rectosigmoid, or half way along the transverse colon, rather than at the splenic flexure. There must be some clear-cut information on this point, and I would be interested to hear of the experience of other clinicians. Adrian Marston Private Consulting Rooms, Woolavington Wing,
Middlesex
Hospital,
London W1 8AA, UK
1 2
Marston A, Pheils MT, Thomas ML, Morson BC. Ischaemic colitis. Gut 1966; 7: 1. Marston A. Ischaemia of the gut. In: Pounder, Misciewicz, eds. Diseases of the gut and pancreas. London: Blackwell Scientific, 1987.
1239