Background Observational studies suggesting that immunizations may strongly decrease the risk of dementia had several methodological limitations. Thus, we assessed whether common vaccines are associated with the risk of dementia. Methods We assembled a population-based cohort of dementia-free individuals in the UK’s CPRD aged ≥50 years between 1988 and 2018. Using a nested case-control approach, we matched each case of dementia with four controls. Conditional logistic regression yielded confounder-adjusted odds ratios (ORs) with 95% confidence intervals (CIs) of dementia associated with common vaccines >2 years before the index date compared with no exposure during the study period. Moreover, we applied a 10-year lag period and used active comparators (participation in breast or prostate cancer screening) to account for detection bias. Results Common vaccines were associated with an increased risk of dementia (OR, 1.38; 95% CI, 1.36-1.40), compared with no exposure. Applying a 10-year lag period (OR, 1.20; 95% CI, 1.18-1.23) and comparing versus prostate cancer screening (OR, 1.19; 95% CI, 1.11-1.27) but not versus breast cancer screening (OR, 1.37; 95% CI, 1.30-1.45) attenuated the risk increase. Conclusions Common vaccines were not associated with a decreased risk of dementia. Unmeasured confounding and detection bias likely accounted for the observed increased risk.

Objective Owing to the potential role of the gut-lung axis in carcinogenesis, we assessed the incidence of gastric cancer in patients with chronic obstructive pulmonary disease (COPD). Methods Using Quebec’s administrative databases, we assembled a cohort of 118 913 patients aged 40 years and older with COPD from 1995 to 2015. We calculated age-standardized incidence rate ratio (IRR) and 95% confidence interval (CI) for gastric cancer, comparing patients with COPD to the Quebec general population. We evaluated temporal changes in incidence by calculating annual percentage change (APC) and stratified the analysis by anatomical site. Results Between 1995 and 2015, 279 patients with COPD developed gastric cancer (54.0 cases per 100 000 person-years). The overall age-standardized incidence rate in patients with COPD was comparable to the general population (IRR, 1.05; 95% CI, 0.79–1.39). However, the IRR increased over time (APC, 4.40%; P = 0.0101), due to the growing rate of gastric cancer in patients with COPD (APC, 1.90%; P = 0.2666) and the declining rate in the Quebec population (APC, −2.40%; P < 0.0001). Conclusions The overall risk of gastric cancer in patients with COPD did not differ from the general population; however, the risk among patients has increased over the years. These findings provide insights as to whether long-term follow-up for gastric cancer risk in COPD is warranted.

BackgroundThe growing evidence for an infectious etiology of dementia supports the investigation of immunization as a preventative intervention. Prior observational studies suggesting that common vaccines are associated with an up to 60% decreased risk of dementia had several methodological limitations. Thus, to provide evidence for this question, we assessed in a large population whether common vaccines are associated with a decreased risk of dementia.MethodWe conducted a population‐based cohort study with a nested case‐control analysis using the Gold and Aurum datasets from the United Kingdom’s Clinical Practice Research Datalink (CPRD). The study cohort included all dementia‐free individuals aged ≥50 years enrolled in the CPRD between January 1988 and December 2018, and followed until March 2021. Each case of dementia identified during follow‐up was matched on sex, age, cohort entry date, duration of follow‐up, and CPRD dataset with up to four controls randomly selected via risk‐set sampling. Conditional logistic regression yielded confounder‐adjusted odds ratios (ORs) with 95% confidence intervals (CIs) of dementia associated with exposure to common vaccines (influenza, pneumonia, shingles, tetanus, diphtheria or pertussis) >2 years before the index date compared to no exposure to these vaccines during the study period. In sensitivity analyses, we applied a longer lag period (10 years) and used active comparators (participation in screening programs for breast and prostate cancer) to account for detection bias.ResultOur study cohort included 13,383,431 dementia‐free individuals aged ≥50 years, including 212,562 who developed dementia over a mean 10‐year follow‐up (mean age 70 years; 62% female). Exposure to common vaccines was associated with an increased risk of dementia (OR, 1.38; 95% CI, 1.36‐1.40), compared with no exposure, driven mostly by immunization for influenza (OR, 1.39; 95% CI, 1.37‐1.41). Applying a longer lag period (OR, 1.22; 95% CI, 1.20‐1.24) and using active comparators (versus breast cancer screening: OR, 1.34; 95% CI, 1.26‐1.42 / versus prostate cancer screening: OR, 1.22; 95% CI, 1.14‐1.31) slightly attenuated the risk increase.ConclusionOur large population‐based study showed no decreased risk of dementia associated with exposure to common vaccines. The observed increase in the risk is likely a result of detection bias.

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SummaryBendamustine (B) with rituximab (R) has become the preferred regimen for patients with indolent lymphoma in Ontario, Canada, compared to R with cyclophosphamide, vincristine, prednisone (CVP) or cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP). We conducted a propensity‐matched retrospective cohort population‐based study of patients treated with R‐CVP/CHOP from 2005 to 2012 and patients treated with BR from 2013 to 2018. The primary outcome was 5‐year overall survival (OS), and secondary outcomes included toxicities and healthcare utilization. The 5‐year OS for patients treated with BR (n = 2023) and R‐CVP/CHOP (n = 2023) was 80% and 75% respectively. Treatment with BR was associated with improved OS (HR 0.79, 95% CI 0.69–0.91). During the first 9 months, patients treated with BR versus R‐CVP/CHOP had a higher number of admissions for infection (22% compared to 17%, p < 0.01) and a higher number of mean ED visits (mean 1.01 ± 1.68 visits vs. 0.85 ± 1.51 visits, p < 0.01). This trend persisted for 3 years. The adjusted 5‐year OS for patients 75 years and older did not differ based on treatment regimen (55.5% for BR vs. 55.4% for R‐CVP/CHOP). Our study supports the use of BR for patients with indolent lymphoma requiring treatment but suggests increased risk of certain toxicities warranting careful patient selection.