Tobacco smoking and meningococcal disease in adolescents and young adults: a systematic review and meta-analysis.

OBJECTIVES: Systematically review the evidence on the association between active and passive tobacco smoking and invasive meningococcal disease (IMD) in adolescents and young adults aged 15-to-24-years. METHODS: Electronic searches were conducted in Ovid MEDLINE, EMBASE, and Web of Science to June 2020. Reference lists were hand-searched. Two independent reviewers screened articles for eligibility. Risk of bias was assessed using an adapted Risk of Bias in Non-Randomised Studies - of Interventions tool. Meta-analyses were conducted using random-effects models. RESULTS: Of 312 records identified, 13 studies were included. Five studies provided data on the association between active smoking and IMD in the target age group; pooled odds ratio (OR): 1.45 (95% CI: 0.93-2.26). The overall OR, including eight studies with a wider participant age range, was 1.45 (95% CI: 1.12-1.88). For passive smoking, the equivalent ORs were 1.56 (95% CI: 1.09-2.25) and 1.30 (95% CI: 1.06-1.59) respectively. All studies were at high risk of bias. CONCLUSIONS: Active and passive smoking may be associated with IMD in adolescents and young adults. Since active smoking has also been linked to meningococcal carriage, and passive smoking to IMD in young children, smoking cessation should be encouraged to reduce transmission and IMD risk in all ages.

Cannabis use and the risk of tuberculosis: a systematic review.

BACKGROUND: Cannabis has been identified as a possible risk factor in some tuberculosis (TB) outbreaks. As the most widely used (largely) illegal substance in Western countries this may be an important public health concern. We aim to systematically review the evidence on the association between cannabis use and TB (latent infection and active disease) to inform ongoing and future TB prevention and control strategies. METHODS: We conducted a systematic review. We searched Ovid Medline, Embase and PsycInfo, together with the World Health Organization website and Google Scholar, for all years to January 2018. Reference lists and conference abstracts were hand-searched, a forward citation search was conducted on the Web of Science, and experts were contacted. Two authors independently screened studies for inclusion, extracted data and assessed risk of bias using an adapted version of ROBINS-I ("Risk of Bias in Non-randomised Studies - of Interventions"). Data were narratively synthesised. RESULTS: Of 377 records identified, 11 studies were eligible. Study designs were heterogeneous. Six studies utilised a relevant comparator group. Four of these investigated the association between cannabis use and latent TB infection; all provided some evidence of an association, although only two of these had adjusted for confounders. The remaining two comparator studies investigated the association between cannabis use and active TB disease; neither found evidence of an association after adjusting for confounding. All six studies were at "Serious" risk of bias. The five studies which did not utilise a relevant comparator group were all indicative of TB outbreaks occurring among cannabis users, but the quality of the evidence was very weak. CONCLUSIONS: Evidence for an association between cannabis use and TB acquisition is weak. The topic warrants further robust primary research including the collection of consistent and accurate exposure information, including cannabis use practices, dose and frequency, and adjustment for confounders.

Impact of opioid substitution therapy on the HIV prevention benefit of antiretroviral therapy for people who inject drugs.

OBJECTIVE: A recent meta-analysis suggested that opioid substitution therapy (OST) increased uptake of antiretroviral treatment (ART) and HIV viral suppression. We modelled whether OST could improve the HIV prevention benefit achieved by ART among people who inject drugs (PWID). METHODS: We modelled how introducing OST could improve the coverage of ART across a PWID population for different baseline ART coverage levels. Using existing data on how yearly HIV-transmission risk is related to HIV plasma viral load, changes in the level of viral suppression across the population were used to project the relative reduction in yearly HIV-transmission risk achieved by ART, with or without OST, compared with if there was no ART - defined here as the prevention effectiveness of ART. RESULTS: Owing to OST use increasing the chance of being on ART and achieving viral suppression if on ART, the prevention effectiveness of ART for PWID on OST (compared with PWID not on OST) increases by 44, 31, or 20% for a low (20%), moderate (40%), or high (60%) baseline ART coverage, respectively. Improvements in the population-level prevention effectiveness of ART are also achieved across all PWID, compared with if OST was not introduced. For instance, if OST is introduced at 40% coverage, the population-level prevention effectiveness of ART could increase by 27, 20, or 13% for a low (20%), moderate (40%), or high (60%) baseline ART coverage, respectively. CONCLUSION: OST could improve the HIV prevention benefit of ART; supporting strategies that aim to concurrently scale-up OST with ART.

Incidence, patterns, and predictors of repeat pregnancies among HIV-infected women in the United Kingdom and Ireland, 1990-2009.

OBJECTIVE: To explore the pattern of repeat pregnancies among diagnosed HIV-infected women in the United Kingdom and Ireland, estimate the rate of these sequential pregnancies, and investigate the demographic and clinical characteristics of women experiencing them. DESIGN: Diagnosed HIV-infected pregnant women are reported through an active confidential reporting scheme to the National Study of HIV in Pregnancy and Childhood. METHODS: Pregnancies occurring during 1990-2009 were included. Multivariable analyses were conducted fitting Cox proportional hazards models. RESULTS: There were 14,096 pregnancies in 10,568 women; 2737 (25.9%) had 2 or more pregnancies reported. The rate of repeat pregnancies was 6.7 (95% confidence interval: 6.5 to 7.0) per 100 woman-years. The proportion of pregnancies in women who already had at least 1 pregnancy reported increased from 20.3% (32 of 158) in 1997 to 38.6% (565 of 1465) in 2009 (P < 0.001). In multivariable analysis, the probability of repeat pregnancy significantly declined with increasing age at first pregnancy. Parity was also inversely associated with repeat pregnancy. Compared with women born in the United Kingdom or Ireland, those from Europe, Eastern Africa, and Southern Africa were less likely to have a repeat pregnancy, whereas women from Middle Africa and Western Africa were more likely to. Maternal health at first pregnancy was not associated with repeat pregnancy. CONCLUSIONS: The number of diagnosed HIV-infected women in the United Kingdom and Ireland experiencing repeat pregnancies is increasing. Variations in the probability of repeat pregnancies, according to demographic and clinical characteristics, are an important consideration when planning reproductive health services and HIV care for people living with HIV.

Who is being tested by the English National Chlamydia Screening Programme? A comparison with national probability survey data.

OBJECTIVES: We compare data collected by England's National Chlamydia Screening Programme (NCSP) with national probability survey data to examine demographic and behavioural differences that may be important in understanding who the NCSP is reaching and interpreting chlamydia positivity. METHODS: Data for 538,119 men and women aged 16-24 years who were screened in 2008 and data collected from 2180 interviewees in Britain's second National Survey of Sexual Attitudes and Lifestyles 1999-2001 (Natsal-2), of whom 644 were tested for chlamydia, were compared using the χ2 statistic and logistic regression. RESULTS: Compared with Natsal-2, the NCSP tested more women (67% vs. 49%). NCSP participants were more likely to be younger: 29% were 16-17 years versus 16% of men and 15% of women in Natsal-2; from ethnic minority groups: 17% of men and 14% of women versus 8% and 6%, respectively, in Natsal-2; not to have used condoms at last sex: 66% of men and 68% of women versus 48% and 63%, respectively, in Natsal-2: and more likely to report two or more partners in the last year: 62% of men and 47% of women versus 47% and 30%, respectively, in Natsal-2. In multivariate analyses, higher AOR of chlamydia positivity were found for those reporting non-use of condoms and for those reporting multiple partners in both the NCSP and Natsal-2. CONCLUSIONS: The NCSP is testing young people at increased risk of chlamydia. The impact of this testing bias on the effectiveness of the programme should be evaluated.