Since there is no cure for HIV, therefore antiretroviral therapy must be taken life-long. Some of the HIV medications can negatively impact the health of the bone and is even more exacerbated in perinatally HIV-injected children and adolescents because this is the period when the bone peaks. Bone loss during this period can be devastating and increase the risk for developing weak bones later in life. Supplementation of calcium and vitamin D have not been well studied in HIV-infected children and adolescents in developing countries. Therefore it is not clear whether higher doses of these supplementations can thwart the damages or not.

Adverse bone health is one of the major long-term complications among perinatally HIV-infected children and adolescents receiving ART. Since a great deal of bone mineral accrual occurs during the adolescent years and the peak attainment is usually seen at age 18 years, the loss of bone deposition during this period could lead to serious consequences, particularly increased risk of osteoporosis and bone fragility in later of life. A previous study demonstrated that prevalence of low BMD among perinatally HIV-infected Thai children and adolescents was high (25%). However, the prevention strategies such as calcium and vitamin D supplementation which are widely recommended by many guidelines for preventing of osteoporosis and bone fracture have not been well studied to prove their effectiveness among HIV-infected children and adolescents, especially in resource-limited countries. This is considered as the critical research question in pediatric HIV/AIDS field which are urgently required robust and in-depth investigations.

This randomized clinical trial study will provide important information about the effect of calcium and high dose (comparing to normal dose) vitamin D supplementation on BMD among ART-experienced, perinatally acquired HIV-infected children and adolescents to best understand the relative contributions of the supplementation to improve bone health status. This study will address research questions, fill gaps in knowledge, and draw clinician attentions to the important long-term medical complications in children and adolescents who are growing up with HIV. Moreover, this study will inform healthcare providers and policy makers about the importance of calcium and vitamin D supplementation as one of the measurement to prevent long-term deterioration of bone mass and the mean to promote bone health among these populations.

The funding for this study is the National Research University, Chiang Mai University.

Inclusion criteria:

• Participants age 10-20 years.
• Have a history and/or medical record of HIV infection.
• Have a history and/or medical record and/or maternal HIV status confirmed of perinatally acquired HIV infection.
• Have virological suppression after receiving ART, defined as plasma HIV RNA less than 400 copies/mL within 12 months prior to screening.
• Participants who had been evaluated for BMD (have BMD result) within 1 year prior to entry visit.
• Caregivers and/or participants gives written inform consent/assent form.

Exclusion criteria:

• Participants who have a documented history of bone fracture at any time prior to screening.
• Participants who have received any form of calcium greater than 1000 mg/day of elemental calcium at least once within 6 months prior screening.
• Participants who have received any form of vitamin D (e.g., ergocalciferol or cholecalciferol) supplementation greater than 400 IU/day at least once within 6 months prior to screening.
• Participants who have received any past pharmacologic treatment for low bone density or osteoporosis (e.g., alendronate) at any time prior to screening.
• Participants who have a documented history of growth hormone deficiency at any time or using growth hormone within 6 months prior to screening.
• Participants who have a documented history of primary hyperparathyroidism, hypoparathyroidism, or cushing syndrome at any time prior to screening.
• Participants who have a documented prior history of kidney stone, renal failure, or renal function impairment (serum creatinine >2 mg/dL).
• Participants who have a documented prior history of chronic active liver diseases, or liver impairment (alanine aminotransferase [ALT] >100 IU/L at least 2 times within 6 months).
• Participants who have a documented prior history of thalassemia major (homozygous β-Thalassemia or β-Thalassemia/Hemoglobin E) or sickle cell disease.
• Participants use any oral, intravenous, or inhaled steroids within 6 months prior to study entry (intranasal steroid use is allowed).
• Participants who have received anticonvulsant medications (phenytoin, phenobarbital, carbamazepine), methotrexate, within 6 months prior to screening.
• Pregnancy or breast feeding
• Participants who have any condition that, in the opinion of the site investigator, would compromise the subject's ability to participate in the study.