Bone Mineral Density & Osteoporosis

Bone mineral density (BMD) is mg mineral per cm2 bone.

 

In the old hypothesis, a high BMD is protective against osteoporosis, and therefore must be increased as much as possible.

But a low BMD due to a lifetime excessive calcium turnover is fundamentally different from a low BMD due to low calcium intake;

 

* BMD is highest and about similar in those countries where most milk is consumed and osteoporosis incidence is highest, like the USA, Australia, Switzerland, the UK and Northern Europe. (1) Italians also drink very much milk, have a high BMD, and Italian osteoporosis incidence is very high too. (2)

 

* BMD in Polish children is lower than US children (3), and so is milk consumption (22% less) and Polish osteoporosis incidence (4).

 

* Both BMD and hip fracture risk are lower in Chinese (5). And in some part of their bones they even have a higher BMD decrease rate (6). (but in some part of their bones the they reach peak BMD 5-10 years later than their counterparts, and is BMD decrease rate lower (7))

And their lower BMD is not due to genetic differences; Chinese who immigrated to Denmark more than 12 years ago have a similar BMD to that of the Danish. (8)

 

* Hip-BMD in Taiwanese is 10 to 15% lower as in Caucasians, and hip fracture incidence is, like in mainland Chinese, far lower. (9)

 

* Japanese osteoporosis incidence is also lower, and so is their BMD (10). And also BMD decrease rate is higher in some part of the bones. (11)

And this is not due to genetic differences either; America-born Japanese women have BMD values equivalent to those of whites. (12)

 

* Because fracture rates among African-American women are lower than among Caucasian women, ‘they’ thought African Americans therefore must have higher BMD, which however is not the case. (13)

 

* In Gambia, BMD, calcium intake and osteoporosis incidence is very low. (14) And again, this is not ‘genetic, since there are no significant differences in BMD and bone turnover in Gambian and Caucasian children living in the UK (15).

 

 

The belief of scientists that a high BMD is protective against osteoporosis, is based on a lower BMD in osteoporosis patients and in women.

But BMD in osteoporosis patients is lower due to excessive erosion. And in women BMD is lower due to a monthly increase in bone turnover, due to monthly fluctuations in estrogen level. (see ”Calcium Hormones”)

Conclusion

BMD on itself does not predict osteoporosis risk.

A natural low BMD due to a low calcium intake is protective against osteoporosis, for calcium turnover has been structurally low.

A low BMD caused by excessive calcium turnover is dangerous and enhances osteoporosis.

Exercise

Many studies have shown that calcium intake (16) and physical activity can increase BMD. (17) Especially excessive high calcium intake (over 1200 mg) (18) and intensive physical training can. (19)

But because they body desperately tries to limit the intake of excessive calcium, also many studies have shown non-significant effects of calcium intake (or normal physical activity) on BMD. (20)

 

In elderly women BMD is either naturally decreased, which is not dangerous, or it is decreased due to excessive calcium turnover, which can cause osteoporosis.

If the low BMD is due to intake of too much calcium, physical exercise can increase BMD very effectively. And if BMD has naturally decreased, both excessive calcium and physical exercise can increase BMD values. That is why both physical activity and calcium intake can increase BMD values in elderly women very effectively. (21)



Sources

Abstracts of most sources can be found at The National Library of Medicin

 

(1) Mazess RB, et al, Bone density of the spine and femur in adult white females. Calcif Tissue Int 1999 Aug;65(2):91-9. , Versluis RG, et al, [Prevalence of osteoporosis in postmenopausal women in family practice]. [Article in Dutch], Ned Tijdschr Geneeskd 1999 Jan 2;143(1):20-4. , Kroger H, et al, Dual-energy X-ray absorptiometry in normal women: a cross-sectional study of 717 Finnish volunteers. , Falch JA, et al, [Bone mineral density measured by dual X-ray absorptiometry. A reference material from Oslo]. [Article in Norwegian] Tidsskr Nor Laegeforen 1996 Aug 20; 116 (19): 2299-302. , Sheth RD, et al, Bone mineral density in geographically diverse adolescent populations. Pediatrics 1996 Nov; 98(5):948-51. , Osteoporos Int 1992 May;2(3):135-40. , Laitinen K, et al , Bone mineral density measured by dual-energy X-ray absorptiometry in healthy Finnish women. Calcif Tissue Int 1991 Apr;48(4):224-31. , Pocock NA, et al, Bone mineral density in Australia compared with the United States. J Bone Miner Res 1988 Dec;3 (6) :601-4.

(2) Guglielmi G, et al, Age-related changes assessed by peripheral QCT in healthy Italian women. Eur Radiol 2000;10(4):609-14. , del Puente A, et al, Epidemiology of osteoporosis in women in southern Italy. Aging (Milano) 1998 Feb; 10 (1) :53-8.

(3) Lorenc RS, et al, [Evaluation of bone mass in children in a national sample of the population]. [Article in Polish] Pol Tyg Lek 1993 Nov;48 Suppl 3: 16-9.

(4) Lips P. Epidemiology and predictors of fractures associated with osteoporosis. Am J Med 1997 Aug 18;103(2A):3S-8S; discussion 8S-11S

(5) Ling X, et al, Vertebral fractures in Beijing, China: the Beijing Osteoporosis Project. J Bone Miner Res 2000 Oct;15 (10): 2019-25. , Xu SZ, et al, The new model of age-dependent changes in bone mineral density. Growth Dev Aging 1997 Spring;61(1):19-26. , Cheng G, et al, [Relative contribution of ageing and menopause to the changes of lumbar bone density in 1,400 Beijing women]. [Article in Chinese] Chung Hua Fu Chan Ko Tsa Chih 1997 Sep;32 (9): 532-4. , Kao CH, et al, Normal data for lumbar spine bone mineral content in healthy elderly Chinese: influences of sex, age, obesity and ethnicity. Nucl Med Commun 1994 Nov;15 (11): 916-20.

(6) Qin M, et al, [Normal spinal changes of bone mineral density in 445 individuals: assessment by quantitative computed tomography]. [Article in Chinese] Chung Kuo I Hsueh Ko Hsueh Yuan Hsueh Pao 1996 Dec;18 (6): 439-43

(7) Xiaoge D, et al, Bone mineral density differences at the femoral neck and Ward's triangle: a comparison study on the reference data between Chinese and Caucasian women. Calcif. Tissue Int. 2000 / 67 (3) / 195-198.

(8) Wang Q, et al, Bone mineral density in immigrants from southern China to Denmark. A cross-sectional study. Eur. J. Endocrinol. 1996 / 134 (2) / 163-167.

(9) Tsai KS, Osteoporotic fracture rate, bone mineral density, and bone metabolism in Taiwan. J Formos Med Assoc 1997 / 96 (10) / 802-805.

(10)Dennison, E. et al,  Bone loss in Great Brittain and Japan : a comparative longitudinal study. Bone 1998 / 23 (4) / 379-382. , Hagiwara S, et al, Quantification of bone mineral content using dual-photon absorptiometry in a normal Japanese population. J Bone Miner Res 1989 Apr;4 (2) :217-22.

(11) Ito M, et al, Spinal trabecular bone loss and fracture in American and Japanese women. Calcif Tissue Int 1997 Aug;61(2):123-8. , Ohmura A, et al, Bone density and body composition in Japanese women. Calcif Tissue Int 1997 Aug;61 (2): 117-22.

(12) Kin K, et al, Bone density and body composition on the Pacific rim: a comparison between Japan-born and U.S.-born Japanese-American women. J Bone Miner Res 1993 Jul;8 (7) :861-9

(13) Kessenich CR, Osteoporosis and african-american women. Womens Health Issues 2000 / 10 (6) / 300-304. , Cauley JA, et al, Calcaneal ultrasound attenuation in older African-American and Caucasian-American women. Osteoporos Int 1997; 7 (2) : 100-4.

(14) Dibba B, et al, Effect of calcium supplementation on bone mineral accretion in gambian children accustomed to a low-calcium diet. Am J Clin Nutr 2000 / 71 (2) / 544-9. , Aspray TJ, et al, Low bone mineral content is common but osteoporotic fractures are rare in elderly rural Gambian women. J Bone Miner Res 1996 / 11(7) / 1019-25

(15) Dibba B, et al, An investigation of ethnic differences in bone mineral, hip axis length, calcium metabolism and bone turnover between West African and Caucasian adults living in the United Kingdom. Ann Hum Biol 1999 May-Jun; 26 (3): 229-42

(16) Davis JW, et al, Ethnic, anthropometric, and lifestyle associations with regional variations in peak bone mass. Calcif Tissue Int 1999 Aug;65(2):100-5. , Ulrich CM, et al, Lifetime physical activity is associated with bone mineral density in premenopausal women. J Womens Health 1999 Apr;8(3):365-75. , Boot AM, et al, Bone mineral density in children and adolescents: relation to puberty, calcium intake, and physical activity. J Clin Endocrinol Metab 1997 Jan;82(1):57-62. , Hu JF, et al, Dietary calcium and bone density among middle-aged and elderly women in China. Am J Clin Nutr 1993 Aug;58(2):219-27.

(17) Aoyagi K, et al, Calcaneus bone mineral density is lower among men and women with lower physical performance. Calcif Tissue Int 2000 Aug; 67 (2): 106-10.

(18) Kroger H, et al, Bone mineral density measured by dual-energy X-ray absorptiometry in normal men. Eur J Clin Invest 1992 Jul;22(7):454-60.

(19) Sparling PB, et al, Bone mineral density and body composition of the United States Olympic women's field hockey team. Br J Sports Med 1998 Dec;32(4):315-8. , Nordstrom P, et al, Type of physical activity, muscle strength, and pubertal stage as determinants of bone mineral density and bone area in adolescent boys. J Bone Miner Res 1998 Jul;13 (7): 1141-8. , Tsuzuku S, et al, Effects of high-intensity resistance training on bone mineral density in young male powerlifters. Calcif Tissue Int 1998 Oct;63 (4): 283-6.

(20) Bonofiglio D, et al, Critical years and stages of puberty for radial bone mass apposition during adolescence. Horm Metab Res 1999 Aug ;31 (8) : 478-82. , Maggiolini M, et al, The effect of dietary calcium intake on bone mineral density in healthy adolescent girls and young women in southern Italy. Int J Epidemiol 1999 Jun;28 (3): 479-84. , van Mechelen W, et al, Longitudinal relationships between lifestyle and cardiovascular and bone health status indicators in males and females between 13 and 27 years of age; a review of findings from the Amsterdam Growth and Health Longitudinal Study. Public Health Nutr 1999 Sep;2 (3A) :419-27. , Kardinaal AF, et al, Dietary calcium and bone density in adolescent girls and young women in Europe. J Bone Miner Res 1999 Apr ;14(4) :583-92. , Cheng JC, et al, Determinants of axial and peripheral bone mass in Chinese adolescents. Arch Dis Child 1998 Jun;78 (6) :524-30. , Brahm H, et al, Relationships between bone mass measurements and lifetime physical activity in a Swedish population. Calcif Tissue Int 1998 May; 62 (5) :400-12. , Ho SC, et al, Determinants of peak bone mass in Chinese women aged 21-40 years. III. Physical activity and bone mineral density. J Bone Miner Res 1997 Aug;12 (8) :1262-71. , Shaw CK, An epidemiologic study of osteoporosis in Taiwan. Ann Epidemiol 1993 May ;3 (3) :264-71. , Kroger H, et al, Development of bone mass and bone density of the spine and femoral neck--a prospective study of 65 children and adolescents.  Bone Miner 1993 Dec;23 (3) :171-82.

(21) Ishikawa K, et al, Relation of lifestyle factors to metacarpal bone mineral density was different depending on menstrual condition and years since menopause in Japanese women. Eur J Clin Nutr 2000 Jan;54 (1) :9-13. , Cheng S, et al, Bone mineral density and physical activity in 50-60-year-old women. Bone Miner 1991 Feb;12 (2) :123-32.

 

 

 



For the source of these documents visit: http://www.4.waisays.com/ by by Wai Genriiu