Sanatoria revisited: sunlight and health

Since the 18th century tuberculosis has been a major cause of death throughout the world. It is a highly infectious disease that spreads by droplet infection and finding effective treatment to combat tuberculosis took a great deal of time. One of the first treatments to have some real success was a stay in a sanatorium. Sanatoria were homes that provided patients with good food and fresh air (and therefore sunlight). The first sanatorium to use sunlight therapy (heliotherapy) seriously was founded in Leysin, Switzerland, by Auguste Rollier. Patients built up their sun exposure gradually to prevent sunburn or skin damage. We suggest that heliotherapy was more successful in treating tuberculosis than was appreciated once chemotherapy became available. The birth of heliotherapy coincided with an increased appreciation of the association of sunlight and health among the general public. The secret of its success is the combined effects of sunlight on the skin inducing the production of nitric oxide and vitamin D. Nitric oxide is not only a messenger in the cardiovascular system and responsible for relaxation of vascular muscle but is also involved in the innate immune system. Vitamin D is responsible for immune system functions and multiple studies have found an association between tuberculosis immunity and high vitamin D levels. Therefore, it is understandable that providing tuberculosis patients with sunlight may have boosted their immune system and aided them in the fight against tuberculosis. In view of the high level of resistance to all drug regimens in some patients, perhaps it is time to revive the use of sanatoria in the fight against tuberculosis

Could misreporting of condom use explain the observed association between injectable hormonal contraceptives and HIV acquisition risk?

OBJECTIVE: Some observational studies have suggested an association between the use of hormonal contraceptives (HC) and HIV acquisition. One major concern is that differential misreporting of sexual behavior between HC users and nonusers may generate artificially inflated risk estimates. STUDY DESIGN: We developed an individual-based model that simulates the South African HIV serodiscordant couples analyzed for HC-HIV risk by Heffron et al. (2012). We varied the pattern of misreporting condom use between HC users and nonusers and reproduced the trial data under the assumption that HC use is not associated with HIV risk. The simulated data were analyzed using Cox proportional hazards models, adjusting for the reported level of condom use. RESULTS: If HC users overreport condom use more than nonusers, an apparent excess risk could be observed even without any biological effect of HC on HIV acquisition. With 45% overreporting by HC users (i.e., 9 out of every 20 sex acts reported with condoms are actually unprotected) and accurate condom reporting by nonusers, a true null effect can be inflated to give an observed hazard ratio (HR̂) of 2.0. In a different population with lower overall reported condom use, artificially high HR̂s can only be generated if non-HC users underreport condom use. CONCLUSION: Differential condom misreporting can theoretically produce inflated HR̂ values for an association between HC and HIV even without a true association. However, to produce a doubling of HIV risk that is entirely spurious requires substantially different levels of misreporting among HC users and nonusers, which may be unrealistic. IMPLICATIONS: Considerably differential amounts of condom use misreporting by HC users and nonusers would be needed to produce entirely spurious observed levels of excess HIV acquisition risk among HC users when there is actually no true association

Biomarkers of potential harm in people switching from smoking tobacco to exclusive e-cigarette use, dual use or abstinence: secondary analysis of Cochrane systematic review of trials of e-cigarettes for smoking cessation

Aims This study aims to compare biomarkers of potential harm between people switching from smoking combustible cigarettes (CC) completely to electronic cigarettes (EC), continuing to smoke CC, using both EC and CC (dual users) and using neither (abstainers), based on behaviour during EC intervention studies. Design Secondary analysis following systematic review, incorporating inverse variance random-effects meta-analysis and effect direction plots. Setting This study was conducted in Greece, Italy, Poland, the United Kingdom and the United States. Participants A total of 1299 adults smoking CC (nine studies) and provided EC. Measurements Measurements were conducted using carbon monoxide (CO) and 26 other biomarkers. Findings In pooled analyses, exhaled CO (eCO) was lower in EC versus EC + CC [mean difference (MD) = −4.40 parts per million (p.p.m.), 95% confidence interval (CI) = −12.04 to 3.24, two studies] and CC (MD = −9.57 p.p.m., 95% CI = −17.30 to −1.83, three studies). eCO was lower in dual users versus CC only (MD = −1.91 p.p.m., 95% CI = −3.38 to −0.45, two studies). Magnitude rather than direction of effect drove substantial statistical heterogeneity. Effect direction plots were used for other biomarkers. Comparing EC with CC, 12 of 13 biomarkers were significantly lower in EC users, with no difference for the 13th. Comparing EC with dual users, 12 of the 25 biomarkers were lower for EC, and five were lower for dual use. For the remaining eight measures, single studies did not detect statistically significant differences, or the multiple studies contributing to the outcome had inconsistent results. Only one study provided data comparing dual use with CC; of the 13 biomarkers measured, 12 were significantly lower in the dual use group, with no statistically significant difference detected for the 13th. Only one study provided data on abstainers. Conclusions Switching from smoking to vaping or dual use appears to reduce levels of biomarkers of potential harm significantly