Helicobacter pylori Treatment and Gastric Cancer Risk Among Individuals With High Genetic Risk for Gastric Cancer.

Importance: Helicobacter pylori treatment and nutrition supplementation may protect against gastric cancer (GC), but whether the beneficial effects only apply to potential genetic subgroups and whether high genetic risk may be counteracted by these chemoprevention strategies remains unknown. Objective: To examine genetic variants associated with the progression of gastric lesions and GC risk and to assess the benefits of H pylori treatment and nutrition supplementation by levels of genetic risk. Design, Setting, and Participants: This cohort study used follow-up data of the Shandong Intervention Trial (SIT, 1989-2022) and China Kadoorie Biobank (CKB, 2004-2018) in China. Based on the SIT, a longitudinal genome-wide association study was conducted to identify genetic variants for gastric lesion progression. Significant variants were examined for incident GC in a randomly sampled set of CKB participants (set 1). Polygenic risk scores (PRSs) combining independent variants were assessed for GC risk in the remaining CKB participants (set 2) and in an independent case-control study in Linqu. Exposures: H pylori treatment and nutrition supplementation. Main Outcomes and Measures: Primary outcomes were the progression of gastric lesions (in SIT only) and the risk of GC. The associations of H pylori treatment and nutrition supplementation with GC were evaluated among SIT participants with different levels of genetic risk. Results: Our analyses included 2816 participants (mean [SD] age, 46.95 [9.12] years; 1429 [50.75%] women) in SIT and 100 228 participants (mean [SD] age, 53.69 [11.00] years; 57 357 [57.23%] women) in CKB, with 147 GC cases in SIT and 825 GC cases in CKB identified during follow-up. A PRS integrating 12 genomic loci associated with gastric lesion progression and incident GC risk was derived, which was associated with GC risk in CKB (highest vs lowest decile of PRS: hazard ratio [HR], 2.54; 95% CI, 1.80-3.57) and further validated in the analysis of 702 case participants and 692 control participants (mean [SD] age, 54.54 [7.66] years; 527 [37.80%] women; odds ratio, 1.83; 95% CI, 1.11-3.05). H pylori treatment was associated with reduced GC risk only for individuals with high genetic risk (top 25% of PRS: HR, 0.45; 95% CI, 0.25-0.82) but not for those with low genetic risk (HR, 0.81; 95% CI, 0.50-1.34; P for interaction = .03). Such effect modification was not found for vitamin (P for interaction = .93) or garlic (P for interaction = .41) supplementation. Conclusions and Relevance: The findings of this cohort study indicate that a high genetic risk of GC may be counteracted by H pylori treatment, suggesting primary prevention could be tailored to genetic risk for more effective prevention.

Drug users' awareness of and willingness to use HIV non-occupational post-exposure prophylaxis (nPEP) services in China: a mixed methods study.

BACKGROUND: Drug users are regarded as a high-risk population for HIV infection. Non-occupational post-exposure prophylaxis (nPEP) is internationally regarded as an effective biomedical prevention against HIV but still a small-scale pilot project in China at present. The aim of this study was to understand drug users' awareness of and willingness to use nPEP service in China. METHODS: This mixed methods study consisting of a qualitative study and a cross-sectional survey was conducted in two cities of China from 2018 to 2019. The in-depth interviews were audio-taped, transcribed verbatim and analyzed using thematic framework analysis. Univariate and multivariate logistic regressions were used to examine factors associated with drug users' awareness of and willingness to use nPEP. RESULTS: There were 401 and 19 participants included in quantitative and qualitative study respectively. Among participants in quantitative study, 30.2% had heard of nPEP and 56.7% reported willingness to use nPEP in future HIV exposure. In multivariate analyses, nPEP awareness was associated with age, sex, education level, AIDS knowledge score and HIV risk perception. nPEP willingness was associated with AIDS knowledge score, HIV risk perception, alcohol use, monthly income and awareness of nPEP. The qualitative results showed the barriers to nPEP willingness included the fatigue after taking drugs, high cost and side effects of nPEP medication, long nPEP course, and fear of privacy disclosure. CONCLUSION: Drug users had low nPEP awareness and only about half participants reported willingness to use nPEP. It is essential to promote nPEP education campaigns among drug users, especially for elders, women and those with lower education level. Simultaneously, price regulation, side effect management, psychological support and privacy protection need to be managed well when nPEP is routinized.