The purpose of this study is to determine whether calcium and vitamin D supplement can attenuate bone loss in HIV-infected-patients in Thailand who receive Tenofovir disoproxil fumarate.

Early initiation of antiretroviral therapy (ART) has transformed HIV infection into chronic manageable disease. Although incidence of AIDS-related mortality has decreased, it has increased for other co-morbid conditions including decrease bone mass, osteoporosis, fragility fracture. There are multi-factorial that contribute to bone loss in HIV-infected individuals including HIV virus itself that shift bone remodeling pathway toward bone resorption, lifestyle and behavioral factors, co-morbid conditions and ART.

Initiation of ART is associated with 2%-6% reduction in bone mineral density during the first 2 years of treatment regardless of ART regimens and then stabilization thereafter in the majority of the study. This magnitude of bone loss is similar to postmenopausal women during the first year.

Tenofovir disoproxil fumarate (TDF) is a nucleotide analogue reverse transcriptase inhibitor, has been associated with greater bone loss than other reverse transcriptase inhibitors, that is recommended as the first line treatment in Thailand. Nonetheless there is an evidence in western country that calcium and vitamin D supplement can attenuate bone loss in naive HIV-infected individual who start ART with TDF. Even though many experts recommend to avoid TDF and prefer abacavir, NRTIs which affect bone loss less than other NRTIs, in high fracture risk patients, more than less HIV-infected-patients can access to abacavir in resource limiting country. This research aims to study bone mineral density (BMD) in HIV infected-patient in Thai population who receive tenofovir with calcium and vitamin D supplement.

Inclusion Criteria:

• HIV-1-infected patients who start 3TC or FTC,TDF and EFV within 3 months before enrollment
• Age 18-50 years

Exclusion Criteria:

• CrCl <60mL/min/1.73 m2 ¶-
• CaCO3 supplement >500 mg/day or vitamin D supplement >800 IU/day
• Steroid used (equivalent to prednisolone> 5 mg/day more than 3 months )
• Osteoporosis treatment
• Serum Ca >10.5 g/dL
• History fragility fracture
• Pregnancy or breastfeeding
• Secondary amenorrhea
• Hyperthyroidism
• History of kidney stone
• Current active opportunistic infection