Updates-By Carol A. Kemper, MD, FACP
Updates-By Carol A. Kemper, MD, FACP
Can HIV Accelerate Emphysema in Smokers?
Source: Diaz PT, et al. Ann Intern Med 2000;132:369-372.
The strikingly high incidence of emphysema identified in a relatively young group of HIV-infected persons in this study raises concerns that HIV infection (or its resultant immunological aberrations) may increase the risk of accelerated lung disease. Respiratory symptoms, and the results of pulmonary function studies, bronchoalveolar lavage, and high-resolution chest CT scanning were performed in 114 HIV-infected patients matched for age, sex, and smoking history to 44 seronegative adults. Baseline characteristics were similar for both groups, and there were no differences in the uses of parenteral drugs, crack, cocaine, or marijuana. The mean CD4 cell count in the HIV positive subjects was 320 cells/mm3, with a range of 0-952 cells/mm3.
While a similar number of subjects in each group smoked (~ 63%), 15% of the HIV-positive subjects were diagnosed with emphysema compared with only 2% of seronegative controls (P = 0.025). Furthermore, 37% of the HIV-positive participants vs. none of the HIV-negative controls with a smoking history of 12 pack-years or more had evidence of emphysema (P = 0.011). HIV-positive smokers also had a significantly reduced diffusing capacity (62.1% of predicted), and the numbers of cytotoxic T cells found in their BAL fluid were greater, suggesting a possible mechanism of injury.
Numerous studies document the increased risk of community-acquired pneumonia and other respiratory illness, such as bronchitis and sinusitis, in HIV-infected smokers. Current cigarette use may also increase the risk of oral thrush and AIDS dementia (Burns DN, et al. J Acquir Immune Defic Syndr Hum Retrovirol 1996;13:374-383). While there was no increase in the incidence of opportunistic infection or death in smokers vs. nonsmokers identified by Burns and colleagues, a recent Italian study describes an aggressive pattern of lung cancers, mostly adenocarcinoma, in HIV-positive smokers, many of whom were significantly younger than their seronegative counterparts (38 vs 53 years) (Tirelli U, et al. Cancer 2000;88:563-569).
Every effort should be made to discourage HIV-infected patients from smoking. Although convincing HIV-infected patients to kick the habit may be a challenge, these data should provide additional ammunition, especially given the longer life spans anticipated for many patients with better HIV therapies. Information on smoking cessation classes, nicotine patches, and bupropion should be made available. Also, many patients who choose to smoke marijuana are unaware that when rolled and smoked it has about 20 times the tar of a filtered cigarette. Other routes of administration, such as ingestion or using a water pipe, should be emphasized to those patients who choose to smoke, although the latter may reduce tetrahydrocannabus levels.
Mother’s Milk May Not be Best
Source:Nduati R, et al. JAMA 2000; 283:1167-1174.
While breastfeeding is a known risk for transmission of HIV-1 in developing countries, formula feeding is also associated with a risk of diarrheal mortality. Nduati and colleagues compared the risk of HIV infection and two-year disease free survival in 425 mother-infant pairs randomly assigned to breastfeeding or formula feeding in Nairobi, Kenya, between 1992 and 1998. Infants were breastfed for an average of 17 months, and the compliance with the assigned feedings was remarkably good. Freeze-dried milk formula, which was made in Kenya, was provided without cost to participants. The cost of the formula was 400 Kenyan shillings (about US $7) per tin, or about $300 for six months of formula feeds. Women were advised to boil water for formula feeds to reduce the risk of bacterial contamination.
While the two-year mortality rates were similar between the two groups (20-24.4%), the rate of HIV-free survival was significantly better for formula-fed infants (70%) compared with those who were breastfed (58%) (P = 0.02). The cumulative risk of HIV infection at two years was 36.7% for those who were breastfed vs. 20.5% in the formula-fed group (P = 0.001). The estimated risk of transmission of HIV in the breastfed group was 16.2%; almost one-half of the infections in the breastfed group were therefore attributable to breast milk. About three-fourths of the HIV infections due to breast milk occurred during the first 6 months of life, although transmissions continued to occur throughout the periods of exposure.
This study suggests that the use of formula feedings in areas endemic for HIV may decrease mother-to-child HIV transmission by up to 44%. Unfortunately, not only is the cost of formula feeding an obstacle for most women in sub-Saharan Africa, but Nduati et al point out that these mothers had access to sources of relatively clean water and were provided specific information on safe formula feeding techniques. In areas where this is not the case, the infant mortality associated with formula feeding could outweigh the risks of breastfeeding.
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