Determinants of energy intake and energy expenditure in HIV and AIDS

To determine the relative importance of various factors in the causation of wasting related to human immunodeficiency virus (HIV), quantitative analys is and linear structural modeling was performed on energy metabolism data c ollected longitudinally and prospectively from 33 men positive for the huma n immunodeficiency virus at 105 time points over a 3-y period before the er a of highly active antiretroviral therapy. Measured variables included ener gy intake, total energy expenditure, resting energy expenditure, rate of ch ange in weight, CD4 count, clinical status, appetite, and mood. Derived var iables included energy balance, activity-related energy expenditure, and ph ysical activity level. Relative contributions were assessed by linear struc tural modeling based on multiple regression expressing results as path coef ficients for individual relationships. The primary determinant of energy ba lance was energy intake (r = 0.80). Total energy expenditure made a very mi nor contribution to energy balance (r = -0.04). Total energy expenditure wa s primarily determined by activity level (r = 0.91), which itself was negat ively related to the presence of opportunistic infection and CD4 count. Ene rgy intake was related to activity level(r = 0.28) and appetite (r = 0.30), which were closely interrelated (r = 0.59). Such linear structural models allow quantitative importance to be apportioned to factors determining weig ht change in those infected with HIV and represent a powerful tool for futu re metabolic studies. Nutrition 2000;16: 101-106. (C) Elsevier Science Inc. 2000.