Bone Mineral Density Across Age and
Gender in Navajo People
Karla Miller1, Molly McFadden2, Khe-ni Ma2, Tracy Frech1, Lillian Tom-Orme2, Laurie J. Moyer-Mileur3,
Martha Slattery2, Tom Greene2, Maureen A. Murtaugh2
Divisions of Rheumatology1, and Epidemiology 2 and Dept of Pediatrics3, University of Utah, Salt Lake City,
Utah
Disclosures
• We have no conflicts to disclose.
Learning Objectives1. To describe bone mineral density (BMD), and its
components, in Navajo men and women 2. To examine differences in BMD of Navajo women
compared to BMD of other ethnic groups reported by the Third National Health And Nutrition Examination Survey (NHANES III).
3. To examine differences in BMD of Navajo men compared to BMD of other ethnic groups reported by NHANES III.
4. To discuss the clinical guidelines related to screening for and diagnosis of osteopenia and osteoporosis that should be utilized in this population, and the general population.
Background Few reports examine bone mineral density
(BMD) among American Indian (AI) populations in the United States
In AI women, BMD & 5-year fracture risk is similar to non-Hispanic (NH) white women.1,2
Differences in BMD across various ethnic groups in the United States have been described.3-6
Background A Canadian study showed that differences in
calcaneal, and total body BMD were explained by lower lean to fat mass in Aboriginal women as compared to white women.7
This study later showed that weight was directly related to BMD, and larger bone area (BA) in Aboriginal women seemed to be responsible for differences in BMD.8
Background Recent studies have examined differences in
BMD across multiple ethnic groups in men, but American Indian populations were not included in these assessments.9, 10
Data addressing BMD of AI men is not presently available.
Purpose
To compare bone mineral density (BMD) as defined by bone mineral content (BMC) and
measured bone area (BA) by age and gender in an adult Navajo population to those reported in other ethnicities by the
NHANES III
Study Population
• The participants of this bone health study were a randomly selected sub-set of the Education And Research Toward Health (EARTH) study 11
• Participants (N=1100) were selected randomly from the Shiprock location of men and women over the age of 18 to fill age and gender groups from November 2007 to January 2010.
Methods Hip, spine, and whole body BMD obtained by
a certified DXA technician on a DXA table (Hologic Discovery W) using standard protocols
Height, weight, and waist and hip circumferences were obtained within 1 month of the DXA measurement.
Daily quality control to maintain error below 1%
Methods Age assessed categorically in groups of 20-29,
30-39, 40-49, 50-59, and 60+ years of age. Comparison of the age and gender specific
means of BMD at the femoral neck to NHANES III for large independent samples with normal approximation was used to assess difference. (SAS, v9.2)
Significant differences defined by Chi Square p values less than 0.05, without adjustments for multiple comparisons.
Results: Women BMD and BMC in Navajo women over 30 were
higher than in NH-white women of similar age. BMD and BMC in Navajo women were lower than
in NH-black women, and similar to Mexican American women in all age groups.
BA in Navajo women over the age of 30 was lower than in NH-white women, and similar to NH-black women.
BA in Navajo women was similar to Mexican American women between the ages of 40 and 70, but higher among those at the extremes of age.
NavajoNHANES III NH-WhiteNHANES III NH-Black
NHANES III Mexican A...Navajo
NHANES III NH-WhiteNHANES III NH-Black
NHANES III Mexican A...Navajo
NHANES III NH-WhiteNHANES III NH-Black
NHANES III Mexican A...Navajo
NHANES III NH-WhiteNHANES III NH-Black
NHANES III Mexican A...Navajo
NHANES III NH-WhiteNHANES III NH-Black
NHANES III Mexican A...20
-29
30-3
940
-49
50-5
960
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10.875
0.8580.95
0.8740.883
0.8250.913
0.8670.843
0.7910.915
0.8480.766
0.7370.852
0.7580.698
0.640.738
0.683
Results: Men In general, BMD and BMC in Navajo men
were similar to that of Non-Hispanic white (NH-white) and Mexican American men.
BMD and BMC were lower among Navajo men compared to Non-Hispanic black (NH-black) men in all age groups.
BA in Navajo men was lower than in NH-white and NH-black men, but similar to that of Mexican American men.
NavajoNHANES III NH-whiteNHANES III NH-black
NHANES III Mexican Ame...Navajo
NHANES III NH-whiteNHANES III NH-black
NHANES III Mexican Ame...Navajo
NHANES III NH-whiteNHANES III NH-black
NHANES III Mexican Ame...Navajo
NHANES III NH-whiteNHANES III NH-black
NHANES III Mexican Ame...Navajo
NHANES III NH-whiteNHANES III NH-black
NHANES III Mexican Ame...20
-29
30-3
940
-49
50-5
960
+
0 0.2 0.4 0.6 0.8 1 1.2
0.95
0.934
1.074
0.982
0.9
0.887
1.005
0.922
0.865
0.839
0.935
0.87
0.838
0.813
0.908
0.857
0.791
0.765
0.832
0.807
Discussion Differences in BMD in Navajo women compared to
NH-white women may be accounted for by higher BMC in Navajo women, and higher BA in theNH-white women.
In general, BMD was similar in Navajo men and women when compared to Mexican American women.
In Navajo men, lower BMC may account for differences in BMD when compared to NH-black men.
These are the first data to address BMD among American Indian men.
Conclusion Future studies are needed to determine the clinical
implications posed by differences in BMC and BA among ethnicities, and the significance of our findings with respect to fragility fracture risk.
In addition, further study is needed to establish morbidity and mortality rates due to fragility fracture among American Indian men and women.
Current evidence supports following the International Society for Clinical Densitometry guidelines for for bone density screening among Navajo men and women.
References1. Wampler NS, Chen Z, Jacobsen C, Henderson JA, Howard BV, Rossouw JEc (2005) Bone mineral density of American Indian and Alaska Native women compared with non-Hispanic white women: results from the Women's Health Initiative Study. Menopause 12:536-544. 2. Cauley JA, Wu L, Wampler NS, Barnhart JM, Allison M, Chen Z, Jackson R, Robbins J (2007) Clinical risk factors for fractures in multi-ethnic women: the Women's Health Initiative. J Bone Miner Res 22:1816-18262. 3. Finkelstein JS, Lee ML, Sowers M, Ettinger B, Neer RM, Kelsey JL, Cauley JA, Huang MH, Greendale GA (2002) Ethnic variation in bone density in premenopausal and early perimenopausal women: effects of anthropometric and lifestyle factors. J Clin Endocrinol Metab 87:3057-3067. 4. Jackson KA, Savaiano DA (2001) Lactose maldigestion, calcium intake and osteoporosis in African-, Asian-, and Hispanic-Americans. J Am Coll Nutr 20:198S-207S. 5. Nelson DA, Barondess DA, Hendrix SL, Beck TJ (2000) Cross-sectional geometry, bone strength, and bone mass in the proximal femur in black and white postmenopausal women. J Bone Miner Res 15:1992-1997. 6. Snelling AM, Crespo CJ, Schaeffer M, Smith S, Walbourn L (2001) Modifiable and nonmodifiable factors associated with osteoporosis in postmenopausal women: results from the Third National Health and Nutrition Examination Survey, 1988-1994. J Womens Health Gend Based Med 10:57-65. 7. Leslie WD, Weiler HA, Lix LM, Nyomba BL (2008) Body composition and bone density in Canadian White and Aboriginal women: the First Nations Bone Health Study. Bone 42:990-995. 8. Leslie WD, Metge CJ, Weiler HA, Doupe M, Wood Steiman P, O'Neil JD (2006) Bone density and bone area in Canadian Aboriginal women: the First Nations Bone Health Study. Osteoporos Int 17:1755-1762. 9. Jiang HX, Majumdar SR, Dick DA, Moreau M, Raso J, Otto DD, Johnston DW (2005) Development and initial validation of a risk score for predicting in-hospital and 1-year mortality in patients with hip fractures. J Bone Miner Res 20:494-500.10. Araujo AB, Travison TG, Harris SS, Holick MF, Turner AK, McKinlay JB (2007) Race/ethnic differences in bone mineral density in men. Osteoporos Int 18:943-9511. Slattery ML, Schumacher MC, Lanier AP, Edwards S, Edwards R, Murtaugh MA, Sandidge J, Day GE, Kaufman D, Kanekar S, Tom-Orme L, Henderson JA (2007) A prospective cohort of American Indian and Alaska Native people: study design, methods, and implementation. Am J Epidemiol 166:606-615.
Acknowledgements• Jean Bia, DXA technician• Celena George, DXA technician• Navajo Nation EARTH Advisory Board and IRB• National Cancer Institution grants CA106218,
CA88958, CA89139, and CA96095
• Maureen A. Murtaugh, PhD• Marty Slattery, PhD• Lillian Tom-Orme, PhD• Laurie Moyer-Mileur, PhD• Molly McFadden, MSTAT• Tom Greene, PhD• Mary Murray, MD
