Antiretroviral therapy (ART) in people living with human immunodeficiency virus (HIV) is associated with bone loss, but data are limited in lactation, when physiological bone mineral mobilization is occurring. This research charted changes in areal bone mineral density (aBMD) during and after lactation in Ugandan women with HIV (WWH) initiated onto ART in pregnancy, compared to women without HIV (REF). One-hundred WWH on tenofovir-based ART and 100 REF were enrolled in pregnancy. Lumbar spine (LS), total hip (TH), and whole-body-less-head (WBLH) aBMD were measured by dual-energy X-ray absorptiometry (DXA) at 2, 14, and 26 weeks of lactation, and at 3 months postlactation. The primary outcome was the difference between groups in mean percent change in LS aBMD between 2 and 14 weeks. Statistical analysis was performed in hierarchical repeated measures ANOVA models that corrected for multiple testing. Median age was 23.4 (IQR, 21.0 to 26.8) years. WWH had lower body weight. aBMD decreased in both groups during lactation, but WWH had greater decreases at TH (2-to-26 weeks: WWH [n = 63] −5.9% [95% CI, −6.4 to −5.4] versus REF [n = 64] −4.3% [95% CI, −4.8 to −3.8]; group*time point interaction p = .008). Decreases in LS aBMD were similar in WWH and REF (2-to-26 weeks: −2.0% [95% CI, −2.5 to −1.5]), although there was a tendency toward a smaller decrease in WWH between 2 and 14 weeks (WWH [n = 77] −1.8% [95% CI, −2.2 to −1.4] versus REF [n = 69] −2.9% [95% CI, −3.3 to −2.5]; group*time point interaction p = .08). Postlactation, LS aBMD was higher relative to week 2 in both groups. TH and WBLH aBMD did not return to week 2 values in WWH but did in REF (TH postlactation versus week 2: WWH [n = 61] −3.1% [95% CI, −3.6 to −2.6]; REF [n = 29] +0.1% [95% CI, −0.9 to +1.1]). These data show accentuated bone loss during lactation and only partial skeletal recovery by 3 months postlactation in Ugandan WWH on tenofovir-based ART. Studies are ongoing to understand longer-term consequences for bone health.

Background: Breastfed infants depend on human milk calcium and phosphorus for bone mineral accretion and growth. We reported greater mobilization of bone mineral and delayed skeletal recovery in lactating Ugandan women with HIV initiated on tenofovir-based antiretroviral therapy during pregnancy compared to HIV-uninfected counterparts in the Gumba Study. However, it is unknown if these disruptions in maternal bone metabolism affect milk mineral concentrations. Research Aim: To compare concentrations and patterns of change in milk calcium and phosphorus between lactating women with and without HIV. Methods: A longitudinal observational study was conducted to compare milk mineral concentrations between women with HIV receiving tenofovir-based ART and uninfected women in the Gumba Study. Milk collected at 2, 14, 26, and 52 weeks lactation was analyzed for calcium and phosphorus. Sodium and potassium were measured at 2 and 14 weeks to detect sub-clinical mastitis. Differences in milk composition between 84 women with HIV and 81 uninfected women were investigated. Results: Women with HIV had higher milk calcium than uninfected women at 14 weeks. The percent difference was +10.2% ( SE = 3.0, p = .008) and there was a tendency to greater values at 2 and 26 weeks. Milk calcium decreased in both groups during lactation ( p ≤ .001) but was more pronounced in women with HIV. The magnitude of change within individuals in the 1st year of lactation from 2 to 52 weeks was −28.3% ( SE 3.9) versus −16.5% ( SE 3.5), p for interaction = .05. Differences in milk phosphorus and calcium-to-phosphorus ratio were smaller and mostly not significant. Conclusions: Participants with HIV on tenofovir-based antiretroviral therapy had altered milk mineral composition. Studies are needed to investigate mechanisms and health implications for the woman and infant.

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