Abstinence-plus programs for HIV infection prevention in high-income countries.

BACKGROUND: Abstinence-plus interventions promote sexual abstinence as the best means of preventing acquisition of HIV, but also encourage safer-sex strategies (eg condom use) for sexually active participants. OBJECTIVES: To assess the effects of abstinence-plus programs for HIV prevention in high-income countries. SEARCH STRATEGY: We searched 30 electronic databases (eg CENTRAL, PubMed, EMBASE, AIDSLINE, PsycINFO) ending February 2007. Cross-referencing, hand-searching, and contacting experts yielded additional citations. SELECTION CRITERIA: We included randomized and quasi-randomized controlled trials evaluating abstinence-plus interventions in high-income countries (as defined by the World Bank). Interventions were any efforts that encouraged sexual abstinence as the best means of HIV prevention, but also promoted safer sex. Results were self-reported biological outcomes, behavioral outcomes, and HIV knowledge. DATA COLLECTION AND ANALYSIS: Three reviewers independently appraised 20070 citations and 325 full-text papers for inclusion and methodological quality; 39 evaluations were included. Due to heterogeneity and data unavailability, we presented the results of individual studies instead of a meta-analysis. MAIN RESULTS: Studies enrolled 37724 North American youth; participants were ethnically diverse. Programs took place in schools (10), community facilities (24), both schools and community facilities (2), healthcare facilities (2), and family homes (1). Median final follow-up occurred 12 months after baseline. Results showed no evidence that abstinence-plus programs can affect self-reported sexually transmitted infection (STI) incidence, and limited evidence that programs can reduce self-reported pregnancy incidence. Results for behavioral outcomes were promising; 23 of 39 evaluations found a significantly protective intervention effect for at least one behavioral outcome. Consistently favorable program effects were found for HIV knowledge.No adverse effects were observed. Several evaluations found that one version of an abstinence-plus program was more effective than another, suggesting that more research into intervention mechanisms is warranted. Methodological strengths included large samples and statistical controls for baseline values. Weaknesses included under-utilization of relevant outcomes, self-report bias, and analyses neglecting attrition and clustered randomization. AUTHORS' CONCLUSIONS: Many abstinence-plus programs appear to reduce short-term and long-term HIV risk behavior among youth in high-income countries. Evidence for program effects on biological measures is limited. Evaluations consistently show no adverse program effects for any outcomes, including the incidence and frequency of sexual activity. Trials comparing abstinence-only, abstinence-plus, and safer-sex interventions are needed.

Abstinence-only programs for HIV infection prevention in high-income countries.

BACKGROUND: Abstinence-only interventions promote sexual abstinence as the only means of preventing sexual acquisition of HIV; they do not promote safer-sex strategies (e.g., condom use). Although abstinence-only programs are widespread, there has been no internationally focused review of their effectiveness for HIV prevention in high-income countries. OBJECTIVES: To assess the effects of abstinence-only programs for HIV prevention in high-income countries. SEARCH STRATEGY: We searched 30 electronic databases (e.g., CENTRAL, PubMed, EMBASE, AIDSLINE, PsycINFO) ending February 2007. Cross-referencing, handsearching, and contacting experts yielded additional citations through April 2007. SELECTION CRITERIA: We included randomized and quasi-randomized controlled trials evaluating abstinence-only interventions in high-income countries (defined by the World Bank). Interventions were any efforts to encourage sexual abstinence for HIV prevention; programs that also promoted safer-sex strategies were excluded. Results were biological and behavioral outcomes. DATA COLLECTION AND ANALYSIS: Three reviewers independently appraised 20,070 records and 326 full-text papers for inclusion and methodological quality; 13 evaluations were included. Due to heterogeneity and data unavailability, we presented the results of individual studies instead of conducting a meta-analysis. MAIN RESULTS: Studies involved 15,940 United States youth; participants were ethnically diverse. Seven programs were school-based, two were community-based, and one was delivered in family homes. Median final follow-up occurred 17 months after baseline. Results showed no indications that abstinence-only programs can reduce HIV risk as indicated by self-reported biological and behavioral outcomes. Compared to various controls, the evaluated programs consistently did not affect incidence of unprotected vaginal sex, frequency of vaginal sex, number of partners, sexual initiation, or condom use. One study found a significantly protective effect for incidence of recent vaginal sex (n=839), but this was limited to short-term follow-up, countered by measurement error, and offset by six studies with non-significant results (n=2615). One study found significantly harmful effects for STI incidence (n=2711), pregnancy incidence (n=1548), and frequency of vaginal sex (n=338); these effects were also offset by studies with non-significant findings. Methodological strengths included large samples, efforts to improve self-report, and analyses controlling for baseline values. Weaknesses included underutilization of relevant outcomes, underreporting of key data, self-report bias, and analyses neglecting attrition and clustered randomization. AUTHORS' CONCLUSIONS: Evidence does not indicate that abstinence-only interventions effectively decrease or exacerbate HIV risk among participants in high-income countries; trials suggest that the programs are ineffective, but generalizability may be limited to US youth. Should funding continue, additional resources could support rigorous evaluations with behavioral or biological outcomes. More trials comparing abstinence-only and abstinence-plus interventions are needed.

Independent living programmes for improving outcomes for young people leaving the care system.

BACKGROUND: Independent living programmes (ILPs) are designed to provide young people leaving care with skills that will limit their disadvantage and aid in their successful transition into adulthood. Programmes focus on personal development, independent living skills, education, and vocational support. OBJECTIVES: To assess the effectiveness of independent living programmes for young people leaving the care system. SEARCH STRATEGY: The following electronic databases were searched: Cochrane Register of Controlled Trials (CENTRAL) (Issue 3, 2005); MEDLINE (1966 to June 2005); EMBASE (1980 to June 2005); CINAHL (1982 to June 2005); PsycINFO (1887 to June 2005); Sociological Abstracts (1952 - June 2005); Applied Social Science Index and Abstracts (ASSIA) (1987- June 2005) and Dissertation Abstracts (to June 2005). All bibliographies were cross-referenced, and experts were contacted for unpublished or ongoing studies. SELECTION CRITERIA: Randomised or quasi-randomised controlled trials comparing ILPs to standard care, another intervention, no intervention, or a wait-list control, for young people leaving care systems at their country's statutory age of discharge. DATA COLLECTION AND ANALYSIS: 2196 citations were identified and screened independently by two reviewers. Full text versions were obtained for 54 papers. None met the review's inclusion criteria. MAIN RESULTS: No study was found that met the inclusion criteria of the review. Eighteen studies using nonrandomised or noncomparative designs were found, which generally reported favourable outcomes for ILP participants; however, reliable inferences cannot be drawn from these studies due to their use of weak methodology. AUTHORS' CONCLUSIONS: Results from randomised controlled trials show no evidence of the effectiveness of ILPs in improving or impairing outcomes for young people discharged from care. Further research into ILPs using randomised controlled designs is needed.

Modest hormonal effects of soy isoflavones in postmenopausal women.

Soy isoflavones have been hypothesized to exert hormonal effects in postmenopausal women. To test this hypothesis, we studied the effects of three soy powders containing different levels of isoflavones in 18 postmenopausal women. Isoflavones were consumed relative to bodyweight [control: 0.11 +/- 0.01; low isoflavone (low-iso): 1.00 +/- 0.01; high isoflavone (high-iso): 2.00 +/- 0.02 mg/kg/day] for 93 days each in a randomized crossover design. Blood was collected on day 1 of the study (baseline) and days 36-38, 64-66, and 92-94 of each diet period, for analysis of estrogens, androgens, gonadotropins, sex hormone binding globulin (SHBG), prolactin, insulin, cortisol, and thyroid hormones. Vaginal cytology specimens were obtained at baseline and at the end of each diet period, and endometrial biopsies were performed at baseline and at the end of the high-iso diet period, to provide additional measures of estrogen action. Overall, compared with the control diet, the effects of the low-iso and high-iso diets were modest in degree. The high-iso diet resulted in a small but significant decrease in estrone-sulfate (E1-S), a trend toward lower estradiol (E2) and estrone (E1), and a small but significant increase in SHBG. For the other hormones, the few significant changes noted were also small and probably not of physiological importance. There were no significant effects of the low-iso or high-iso diets on vaginal cytology or endometrial biopsy results. These data suggest that effects of isoflavones on plasma hormones per se are not significant mechanisms by which soy consumption may exert estrogen-like effects in postmenopausal women. These data also show that neither isoflavones nor soy exert clinically important estrogenic effects on vaginal epithelium or endometrium.

Effects of low-level dietary deoxynivalenol on haematological and clinical parameters of the pig.

The subacute toxic effects of dietary deoxynivalenol (DON) were examined in grower pigs during a 32 day feeding period. DON was incorporated into the feed at 0, 1, and 3 mg/kg, added as either the purified toxin (P) or as naturally contaminated corn (N). Growth performance and blood biochemical and haematological parameters were monitored throughout the study. At the higher toxin levels (diets 3P, 3N) significantly lower feed consumption and body weight gains were evident soon after the start of feeding, but while weight gains of pigs fed the pure DON diet (3P) recovered after several days, values for pigs fed the naturally contaminated diet (3N) remained depressed over the course of the study. It is possible that these observations reflected the presence of other unidentified toxic compounds in the naturally contaminated grain. Generally, blood chemistry parameters of pigs fed the contaminated diets were not different from controls, with the exception of alpha-globulin and possibly cortisol in animals receiving diets 3N or 3P. Data suggested that the effect of DON on the alpha-globulin fraction may have been independent of the feed refusal syndrome associated with this toxin. Alterations in several haematological measurements were noted to occur sporadically with the 3 ppm diets, including higher RBC count, haematocrit and platelet level, however these effects could not be separated from the influence of decreased feed intake and were of limited value in diagnosing the effects of low level dietary DON on swine.

Cytogenetic analysis of Day-4 embryos from PMSG/hCG-treated prepuberal gilts.

Prepuberal gilts were treated with pregnant mare serum gonadotropin (PMSG) to study the effects of its dosage on ovulation rate, fertilization rate after artificial insemination, embryo viability, and rate of development and incidence of chromosome abnormalities in Day-4 embryos. Gilts received 750 IU, 1250 IU or 1500 IU of PMSG, followed 72 h later by 500 IU human chorionic gonadotropin (hCG). Gilts were inseminated 28 to 30 h following the hCG injection, and resulting embryos were collected on Day 4 post ovulation. Ovulation rate was higher in the 1250 IU group than in the 1500 IU group or the 750 IU group. The 1500 IU dose caused excessive stimulation of the ovary, resulting in the occurrence of large (>10mm diameter) unovulated follicles, reduced fertilization rate and low embryo recovery rate. There was no difference in the incidence of chromosome abnormalities among the three groups, although the 1500 IU group had higher embryonic mortality than the two lower dose groups. A dose of 1250 IU PMSG increased ovulation rate above that achieved by 750 IU and, therefore, increased the number of oocytes or embryos available for transfer or for other studies, without sacrificing embryo viability or increasing the incidence of chromosome abnormalities.