Longitudinal analysis of bone density in human immunodeficiency virus-infected women

Abstract

Objectives: The objective of the study was to investigate change in bone mineral density (BMD) over time in HIV-infected women in comparison with healthy control subjects similar in age, race, and body mass index (BMI).

Design: This was a prospective cohort study.

Methods: BMD was measured by dual-energy x-ray absorptiometry in 100 HIV-infected females and 100 healthy controls similar in age (41 +/- 1 vs. 41 +/- 1 yr, P = 0.57), BMI (26.1 +/- 0.5 vs. 27.2 +/- 0.4 kg/m(2), P = 0.12), and race (60 vs. 65% non-Caucasian, P = 0.47, HIV-infected vs. controls). Changes in BMD were determined every 6 months over 24 months.

Results: At baseline, HIV-infected subjects had lower BMD at the lumbar spine (1.01 +/- 0.01 vs. 1.07 +/- 0.01 g/cm(2), P = 0.001), hip (0.94 +/- 0.01 vs. 0.98 +/- 0.01 g/cm(2), P = 0.02), and femoral neck (0.83 +/- 0.01 vs. 0.87 +/- 0.01 g/cm(2), P = 0.02). Historical low weight, duration of nucleoside reverse transcriptase inhibitor use, and FSH were significantly associated with lumbar BMD, whereas duration of HIV, BMI, historical low weight, smoking pack-years, N-telopeptide of type 1 collagen, viral load, 25 hydroxyvitamin D, and osteocalcin were associated with hip BMD at baseline. In mixed model longitudinal analyses, BMD remained lower in HIV-infected subjects than in controls over 24 months of follow-up (P = 0.001 for the spine, P = 0.04 for the hip, and P = 0.02 for the femoral neck). These differences remained significant controlling for age, race, BMI, and menstrual function. In contrast, rates of change for the spine (P = 0.79), hip (P = 0.44), and femoral neck (P = 0.34) were not different between the HIV and control groups over 2 yr. In the HIV group, longitudinal changes in BMD were not associated with current protease inhibitor, nucleoside reverse transcriptase inhibitor, or non-nucleoside reverse transcriptase inhibitor use but were associated with CD4 count, weight, FSH, N-telopeptide of type 1 collagen, and baseline BMD.

Conclusions: BMD is reduced at the spine, hip, and femoral neck among women with HIV in relationship to low weight, duration of HIV, smoking, and increased bone turnover. Over 2 yr of follow-up, BMD remained stable but lower in HIV-infected women, compared with control subjects.

Fig. 1

Baseline bone density. *, P < 0.01; **, P < 0.05 vs. control subjects.

Fig. 2

Longitudinal comparison of bone density at the lumbar spine between HIV-infected and control subjects. P < 0.01 for comparison between HIV-infected and control group at baseline; P = 0.001 for overall comparison between groups in longitudinal modeling. No significant differences (P > 0.05) were found in baseline bone density between the HIV-infected patients who completed the study (n = 25) and those who did not complete the study (n = 75) or between the controls who completed the study (n = 25) and those who did not complete the study (n = 75) at any site. Similarly, no significant baseline differences were seen in analyses performed for those completing and not completing the 6-, 12-, and 18-month visits.