The safety of over-the-counter niacin. A randomized placebo-controlled trial [ISRCTN18054903]

BACKGROUND: Niacin is widely available over the counter (OTC). We sought to determine the safety of 500 mg immediate release niacin, when healthy individuals use them as directed. METHODS: 51 female and 17 male healthy volunteers (mean age 27 years SD 4.4) participated in a randomized placebo-controlled blinded trial of a single dose of an OTC, immediate-release niacin 500 mg (n = 33), or a single dose of placebo (n = 35) on an empty stomach. The outcomes measured were self-reported incidence of flushing and other adverse effects. RESULTS: 33 volunteers on niacin (100%) and 1 volunteer on placebo (3%) flushed (relative risk 35, 95% confidence interval (CI) 6.8–194.7). Mean time to flushing on niacin was 18.2 min (95% CI: 12.7–23.6); mean duration of flushing was 75.4 min (95% CI: 62.5–88.2). Other adverse effects occurred commonly in the niacin group: chills (51.5% vs. 0%, P < .0001), generalized pruritus (75% vs. 0%, P = <.001), gastrointestinal upset (30% vs. 3%, P = .005), and cutaneous tingling (30% vs. 0%, P = <.001). Six participants did not tolerate the adverse effects of niacin and 3 required medical attention. CONCLUSION: Clinicians counseling patients about niacin should alert patients not only about flushing but also about gastrointestinal symptoms, the most severe in this study. They should not trust that patients would receive information about these side effects or their prevention (with aspirin) from the OTC packet insert

Estimating Sensitivity of Laboratory Testing for Influenza in Canada through Modelling

Background: The weekly proportion of laboratory tests that are positive for influenza is used in public health surveillance systems to identify periods of influenza activity. We aimed to estimate the sensitivity of influenza testing in Canada based on results of a national respiratory virus surveillance system. Methods and Findings: The weekly number of influenza-negative tests from 1999 to 2006 was modelled as a function of laboratory-confirmed positive tests for influenza, respiratory syncytial virus (RSV), adenovirus and parainfluenza viruses, seasonality, and trend using Poisson regression. Sensitivity was calculated as the number of influenza positive tests divided by the number of influenza positive tests plus the model-estimated number of false negative tests. The sensitivity of influenza testing was estimated to be 33 % (95%CI 32–34%), varying from 30–40 % depending on the season and region. Conclusions: The estimated sensitivity of influenza tests reported to this national laboratory surveillance system is considerably less than reported test characteristics for most laboratory tests. A number of factors may explain this difference, including sample quality and specimen procurement issues as well as test characteristics. Improved diagnosis would permit better estimation of the burden of influenza

HIV and STI Prevalence and Injection Behaviors Among People Who Inject Drugs in Nairobi: Results from a 2011 Bio-behavioral Study Using Respondent-Driven Sampling

There is a dearth of evidence on injection drug use and associated HIV infections in Kenya. To generate population-based estimates of characteristics and HIV/STI prevalence among people who inject drugs (PWID) in Nairobi, a cross-sectional study was conducted with 269 PWID using respondent-driven sampling. PWID were predominantly male (92.5 %). An estimated 67.3 % engaged in at least one risky injection practice in a typical month. HIV prevalence was 18.7 % (95 % CI 12.3–26.7), while STI prevalence was lower [syphilis: 1.7 % (95 % CI 0.2–6.0); gonorrhea: 1.5 % (95 % CI 0.1–4.9); and Chlamydia: 4.2 % (95 % CI 1.2–7.8)]. HIV infection was associated with being female (aOR, 3.5; p = 0.048), having first injected drugs 5 or more years ago (aOR, 4.3; p = 0.002), and ever having practiced receptive syringe sharing (aOR, 6.2; p = 0.001). Comprehensive harm reduction programs tailored toward PWID and their sex partners must be fully implemented as part of Kenya’s national HIV prevention strategy