Prevalence of Osteopenia and Osteoporosis in Navajo Men and Women over 50 across Age and

Body Mass Index (BMI)

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 Objectives• To describe the prevalence of osteopenia and

osteoporosis in Navajo men and women over the age of 50.

• To examine the impact of age and gender on bone mineral density (BMD) in Navajo men and women

• To determine the effects of body mass index (BMI) on BMD in Navajo men and women.

• To compare the prevalence of osteopenia and osteoporosis in Navajo men in women to the prevalence reported for the general population by the Third National Health and Nutrition Examination Survey (NHANES III).

Background

Bone health of American Indian people (AI) has received relatively little research attention.

In AI women BMD & 5-year fracture risk is similar to non-Hispanic

white women.1,2

Obesity is associated with a higher total hip BMD, but lower spine and total body BMD in postmenopausal AI women compared to no-Hispanic white women.1

Reported fragility fracture rates are similar or lower in minority women compared to NH white women, but fracture-related morbidity and mortality may be increased in minority women.3-5

Background

Low bone mass is under-recognized in men, and some data suggest that men may have higher mortality than women after a hip fracture.5

Data addressing BMD of AI men is limited.

Purpose

To describe the prevalence of osteopenia and osteoporosis in in Navajo men and women over the age of 50 as defined by the World

Health Organization (WHO) classification criteria for densitometric diagnosis.

Methods: Study population• The participants of this bone health

study were a randomly selected sub-set of the Education And Research Toward Health (EARTH) study 9

• 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: Data collection

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: Statistical analysis• Data analyzed using SAS version 9.2 (SAS Institute,

Carey, NC). • Significant differences indicated by Chi Square p

values less than 0.05, without adjustments for multiple comparisons.

• Age analyzed by categories <30, 30-40, 40-50, 50-60, and >60 years of age.

• BMI categories included <25, 25-30, 30-35, >35 • T-scores interpreted following the World Health

Organization guidelines

World Health Organization classification criteria

Results: Femoral neck

Prevalence of low bone mass by femoral neck T-scores in women over the age of 50 was 47.9%

Prevalence of osteoporosis by femoral neck T-scores in women over the age of 50 was 6%.

Results: Femoral neck

• Prevalence of low bone mass by femoral neck T-scores in men over 50 was 42.5%

• Prevalence of osteoporosis by femoral neck T-scores in men over 50 was 1.5%.

Results: Lumbar Spine

Prevalence of low bone mass by lumbar spine (L1-4) T-scores in women over 50 was 41%

Prevalence of osteoporosis by lumbar spine (L1-4) T-scores in women over 50 14% of women.

Results: Lumbar Spine

• Prevalence of low bone mass by lumbar spine (L1-4) T-scores in men over 50 was 22%

• Prevalence of low bone mass by lumbar spine (L1-4) T-scores in men over 50 was 4.5%

Results

Total prevalence of low bone mass and osteoporosis was 51.6% and 16.3% in women, and 47% and 5.2% in men.

Bone mineral density increased significantly among both men and women across BMI groups

Results

BMD Across Level of BMI in Women

BMI (kg/m²) < 25 25-30 30-35 > 35

  N= 84 N= 176 N= 191 N= 189

  Mean (SE) Mean (SE) Mean (SE) Mean (SE)

Femoral Neck BMD (g/cm²)

0.735 (0.014)

0.778 (0.010)

0.812 (0.009)

0.872 (0.011)

Total Hip BMD (g/cm²)

0.838 (0.016)

0.895 (0.010)

0.935 (0.011)

1.007(0.013)

Lumbar Spine BMD (g/cm²)

0.969 (0.018)

1.002 (0.012)

1.008 (0.011)

1. 075 (0.013)

Whole Body BMD (g/cm²)

1.041 (0.013)

1.070 (0.010)

1. 080 (0.009)

1. 125(0.011)

BMD Across Level of BMI in Men

BMI (kg/m²) < 25 25-30 30-35 > 35

  N= 66 N= 149 N= 145 N= 94

  Mean (SE) Mean (SE) Mean (SE) Mean (SE)

Femoral Neck BMD (g/cm²)

0.789 (0.012)

0.860 (0.015)

0.903 (0.016)

0.979 (0.022)

Total Hip BMD (g/cm²)

0.911 (0.013)

0.995 (0.015)

1.069(0.016)

1.127 (0.022)

Lumbar Spine BMD (g/cm²)

1.014 (0.022)

1.043 (0.018)

1.097 (0.017)

1.132 (0.024)

Whole Body BMD (g/cm²)

1.108 (0.013)

1.163 (0.013)

1.200(0.014)

1.232 (0.017)

Discussion

This study on prevalence of low bone mass and osteoporosis in Navajo men and women in the Southwestern United States is the largest report in American Indian people.

This study is the first to report on the prevalence of low bone mass and osteoporosis in a population of American Indian men.

Conclusion

• Total prevalence of low bone mass and osteoporosis was 52% and 16% in Navajo women over the age of 50.

• Total prevalence of low bone mass and osteoporosis was and 47% and 5.2% in Navajo men over the age of 50.

Conclusion

Prevalence of low bone mass (osteopenia) and osteoporosis at the hip in Navajo women over the age of 50 is similar to that reported by NHANES III for women.

Prevalence of low bone mass (osteopenia) at the hip in Navajo men over the age of 50 was similar to that reported by NHANES III for men.

However, prevalence of osteoporosis at the hip in Navajo men over the age of 50 was slightly lower than that reported by NHANES III for men.

Conclusion

This study substantiates the previous reports of increases in BMD across BMI in American Indian and other populations.

Implications and Future Research

• Understanding the prevalence of low bone mass and osteoporosis may be helpful in planning healthcare resources for the Navajo Nation.

• The next step in research is to learn how this relates to fragility fracture incidence and mortality using longitudinal data collection.

References1. Wampler NS, Chen Z, Jacobsen C, Henderson JA, Howard BV, Rossouw JE (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 22:1816-1826. 3. Furstenberg AL, Mezey MD (1987) Differences in between black and white elderly hip fracture patients. J Chronic Dis 40:931-938. 4. Jacobsen SJ, Goldberg J, Miles TP, Brody JA, Stiers W, Rimm AA (1992) Race and sex differences in mortality following fracture of the hip. Am J Public Health 82:1147-1150. 5. Ma J, Markides KS, Perkowski LP, Stroup-Benham CA, Lichtenstein M, Goodwin JS (1998) Impact of selected medical conditions on self-reported lower-extremity function in Mexican-American elderly. Ethn Dis 8:52-59. 6. 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. 7. Araujo AB, Travison TG, Harris SS, Holick MF, Turner AK, McKinlay JB (2007) Race/ethnic differences in bone mineral density in men. Osteoporos Int 18:943-953. 8. Sheu Y, Cauley JA, Wheeler VW, Patrick AL, Bunker CH, Ensrud KE, Orwoll ES, Zmuda JM Age-related decline in bone density among ethnically diverse older men. Osteoporos Int 22:599-605.9. . 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, DEXA technician• Celena George, DEXA technician• Navajo Nation EARTH Advisory Board and IRB

• Maureen A. Murtaugh, PhD• Marty Slattery, PhD• Lillian Tom-Orme, PhD• Laurie Moyer-Mileur, PhD• Molly McFadden, MSTAT• Tom Greene, PhD• Mary Murray, MD

• National Cancer Institution grants CA106218, CA88958, CA89139, and CA96095