Risk factors for human immunodeficiency virus infection among Brazilian blood donors: a multicentre case-control study using audio computer-assisted structured interviews.

BACKGROUND: Although risk factors for HIV infection are known, it is important for blood centres to understand local epidemiology and disease transmission patterns. Current risk factors for HIV infection in blood donors in Brazil were assessed. METHODS: A case-control study was conducted at large public blood centres located in four major cities between April 2009 and March 2011. Cases were persons whose donations were confirmed positive by enzyme immunoassays followed by Western blot confirmation. Audio computer-assisted structured interviews (ACASI) were completed by all cases and controls. Multivariable logistic regression was used to estimate adjusted odds ratios (AORs) and associated 95% confidence intervals (CIs). RESULTS: There were 341 cases, including 47 with recently acquired infection, and 791 controls. Disclosed risk factors for both females and males were sex with an HIV-positive person AOR 11.3, 95% CI (4.1, 31.7) and being an IVDU or sexual partner of an IVDU [AOR 4.65 (1.8, 11.7)]. For female blood donors, additional risk factors were having male sex partners who also are MSM [AOR 13.5 (3.1, 59.8)] and having unprotected sex with multiple sexual partners [AOR 5.19 (2.1, 12.9)]. The primary risk factor for male blood donors was MSM activity [AOR 21.6 (8.8, 52.9)]. Behaviours associated with recently acquired HIV were being a MSM or sex partner of MSM [13.82, (4.7, 40.3)] and IVDU [11.47, (3.0, 43.2)]. CONCLUSION: Risk factors in blood donors parallel those in the general population in Brazil. Identified risk factors suggest that donor compliance with selection procedures at the participating blood centres is inadequate.

Protein quality and urea kinetics in prepubertal Chilean schoolboys.

Urea kinetics were measured non-invasively in 12 Chilean schoolboys aged 8-10 years who were receiving one of two diets, either predominantly animal protein or predominantly vegetable protein. Both the diets provided an equivalent level of gross protein, 1.2 g/kg/day. The study diets were given for 10 days to enable adaptation to take place. On the eighth day a single oral dose of 15N15N-urea, 100 mg, was given and the amount of label excreted as 15N15-urea in urine over the subsequent 48 hours was measured. There was little difference in any aspect of urea kinetics between the two diets with urea production (animal, 173 +/- 50 mgN/kg/day; vegetable 179 +/- 53 mgN/kg/day), urea excretion (animal, 86 +/- 19 mgN/kg/day; vegetable, 105 +/- 13 mgN/kg/day), urea nitrogen hydrolysis (animal, 87 +/- 49 mgN/kg/day; vegetable, 74 +/- 42 mgN/kg/day), and the salvaged urea-nitrogen derived from hydrolysis which returned to urea formation (animal, 12 +/- 5 mgN/kg/day; vegetable, 17 +/- 9 mgN/kg/day) all being similar. A very high proportion of the salvage nitrogen derived from urea hydrolysis was maintained within the metabolic pool, about 80%, which was equivalent to 0.4 g protein/kg/day. This is the first time urea kinetics have been measured in children of this age and shows that 57% of the ura produced is excreted in urine on average with about 43% of the urea-nitrogen being salvaged for further metabolic interaction. It is concluded that the vegetable based protein diet taken habitually by Chilean children is metabolically equivalent in terms of urea kinetics to a diet based upon animal protein at this level of intake, but that high rates of salvage of urea nitrogen are found on both diets.