In addition to long-term effects on the blood lipids, which poses a risk of cardiovascular disease, a disturbed fat distribution (lipodystrophy) is another frequently occurring complication in the treatment of HIV-1 infection. This disturbed fat distribution is associated with subcutaneous fat loss in some body parts (particularly the face, arms and legs, and buttocks) and with fat accumulation in other body parts (such as the abdomen, the back of the neck and female breasts). Subcutaneous fat loss is mainly associated with thymidine-containing nucleoside analogues like zidovudine (AZT) and stavudine (d4T). Previous studies in patients receiving antiretroviral treatment for the first time have shown that a combination of TDF / lamivudine (3TC) (the latter drug closely resembles FTC) does not lead to loss of subcutaneous fat (lipoatrophy), as opposed to the combination d4T / 3TC or AZT / 3TC. The cause of fat accumulation is however less clear, but often coincides with changes in blood lipids. The chance of the occurrence of fat accumulation could thus depend on the extent to which an HIV combination therapy coincides with an elevation of blood lipids.