Circulating 25-hydroxycholecalciferol and calcium levels, and alkaline phosphatase activity among people living with and without human immunodeficiency virus and injecting drugs in kenya

Background: People who inject drugs (PWID) and living with the human immunodeficiency virus (PLHIV) are at higher risk of suffering marked derangements in micronutrient levels, leading to poor disease and treatment outcomes. Consequently, this can be monitored by measuring key biomarkers, such as total circulating (serum) 25-hydroxycholecalciferol (25(OH)D₃), calcium, and alkaline phosphatase (ALP) for timely intervention. Therefore, circulating levels of 25(OH)D₃ and calcium, and ALP activity were determined in PWID and are highly active anti-retroviral treatment (HAART)-experienced or -naive, along with those without HIV infection.

Methods: This cross-sectional study compared serum concentrations of 25(OH)D₃, calcium, and ALP in Kenyan PLHIV and were HAART-naive (n = 30) or -experienced (n = 61), PWID and without HIV (n = 132).

Results: Circulating 25(OH)D₃ levels were significantly different amongst the study groups (P < 0.001), and were significantly lower in the HAART-experienced (median, 17.3; IQR, 18.3 ng/ml; P < 0.001) and -naive participants (median, 21.7; IQR, 12.8 ng/ml; P = 0.015) relative to uninfected (median, 25.6; IQR, 6.8 ng/ml) PWID. In addition, the proportions of vitamin D deficiency (55.7%, 40.0%, and 17.4%) and insufficiency (31.1%, 53.3%, and 63.6%) compared to sufficiency (13.1%, 6.7%, and 18.9%; P < 0.001) were greater amongst HAART-experienced, -naive, and uninfected study groups, respectively. Likewise, serum total calcium concentrations were lower in the HAART-experienced relative to HIV-negative (P = 0.019) individuals. Serum ALP activity was also lower in the HAART-experienced in contrast to HIV-negative PWID (P = 0.048). Regression analysis indicated that predictors of circulating 25(OH)D₃ were: age (β = 0.287; R² = 8.0%; P = 0.017) and serum ALP (β = 0.283; R² = 6.4%; P = 0.033) in the HAART-experienced PWID, and serum ALP (β = 0.386; R² = 14.5%; P < 0.001) in the HIV-negative PWID.

Conclusion: This study suggests that HIV-1 infection and HAART, including injection substance use, decrease circulating 25(OH)D₃, calcium and ALP activity. In addition, age and ALP activity are associated with low circulating vitamin D levels in HAART-experienced PWID. The results highlight the importance of incorporating vitamin D and calcium supplementation in treatment and rehabilitation protocols for PLHIV.