Association of hypertension and bone mineral density in an elderly African American female population.

BACKGROUND: Recent studies have shown that hypertension is inversely correlated with bone mineral density (BMD) as determined by dual energy x-ray absorptiometery (DXA) in different ethnic groups. But in most published studies, either the sample size was small or the study was limited by different measurement methods. These limitations leave this association controversial and inconclusive. The current study utilizes a sample of African American females referred for clinical screening of osteoporosis in our center to find out if any association of high blood pressure and BMD in this ethnic group exists. The secondary endpoint was to determine the effect of thiazide diuretics on BMD of the elderly African American females because, theoretically, thiazides are considered to have a positive impact on BMD.

METHODS: In this retrospective, cross-sectional study, 10 years of data were reviewed from 1113 medical records of African American females aged 65 years and older whose BMD values were measured by DXA at the lumbar spine (L1-L4) and both femoral necks (the standard sites for BMD determination) along with their T scores and Z scores (used to determine osteopenia vs osteoporosis). Our exclusion criteria included patients who: (1) were current smokers, (2) had a previous oophorectomy, (3) had a history of corticosteroid use, (4) had a history of biphosphonate use, (5) were on hormone replacement therapy, and (6) were diabetic and taking either pioglitazones or roziglitazones. A total of 148 patients were excluded from the analysis due to either incomplete data or exclusion criteria. The remaining sample was then divided into 2 groups based on their hypertensive status. For the subanalysis, the hypertensive group was further divided into 2 additional groups based on their thiazide usage.

RESULTS: We had complete data on 965 participants, of which 631 (65.3%) had a history of hypertension and 334 (34.7%) did not. Out of 631 hypertensive patients, 173 were found to be using thiazide diuretics as antihypertensive medication, while 458 were without thiazide diurectic use. The proportion of patients with both osteopenia and osteoporosis was similar in those with and without hypertension (50% vs 50%, p = .95 for osteopenia; 18% vs 19%, p = .95 for osteoporosis). There was no significant difference between the BMD at the lumbar spine, and right and left femoral necks between patients with and without hypertension. This lack of association held true when comparing the mean T scores and Z scores at the above sites. Within patients with a history of hypertension, there were no significant differences in the BMD, T score or Z score at any site with and without a history of thiazide diuretic use.

CONCLUSION: Hypertension in elderly African American females aged at least 65 years was not found to be correlated with low BMD at either the lumbar spine (L1-L4) or both femoral necks when confounding factors were taken into consideration. Mean BMD of the hypertensive cohort taking thiazide diuretics was found lower at the lumbar spine as compared to the hypertensive patients not taking thiazide diuretics.