Background: Endometriosis, a prevalent condition among females of reproductive age, may be associated with increased risk of cardiovascular disease (CVD) through chronic inflammation and early menopause. The objective of this study was to estimate the association between endometriosis and subsequent risk of CVD. Methods: We conducted a population-based cohort study using administrative health data from Ontario residents from 1993 to 2015. We compared the incidence of CVD and cardiovascular health outcomes between females with endometriosis and 2 age-matched females without endometriosis. The primary outcome was hospital admission for CVD. Secondary outcomes included in-hospital CVD events of interest and emergency department visits for CVD. We used Cox proportional hazards models to estimate adjusted hazard ratios (HRs) between endometriosis and CVD events. Results: We identified 166 835 eligible patients with endometriosis and matched 333 706 patients without endometriosis. The mean age of those with endometriosis was 36.4 years. Patients with endometriosis had a higher incidence of hospital admission for CVD (195 admissions/100 000 person-years) compared with those without endometriosis (163 admissions/100 000 person-years). Similarly, the incidence of secondary CVD events was slightly higher among patients with endometriosis (292 cases/100 000 person-years) than among those without endometriosis (224 cases/100 000 person-years). Females with endometriosis had an increased risk of hospital admission (adjusted HR 1.14, 95% confidence interval [CI] 1.10–1.19) and secondary CVD events (adjusted HR 1.26, 95% CI 1.23–1.30). Interpretation: In this large, population-based study, endometriosis was associated with a small increased risk of CVD events. Future studies need to investigate potential etiological mechanisms and strategies to decrease long-term CVD risk in patients with endometriosis.

Use of a gestational ("surrogate") carrier is increasingly common. Risk for maternal and neonatal adversity is largely unknown in this birthing population. To determine the risk for severe maternal morbidity (SMM) and severe neonatal morbidity (SNM) in gestational carriers. Population-based cohort study. All of Ontario, Canada. All singleton births at more than 20 weeks' gestation, from 2012 to 2021. Exposure was type of conception, namely, gestational carriage (main exposure), unassisted conception (comparison group 1), and in vitro fertilization (IVF) (comparison group 2). Main composite outcomes were SMM and SNM. Modified Poisson regression models generated weighted relative risks (wRRs) using propensity score-based overlap weighting. Secondary outcomes included hypertensive disorders of pregnancy, cesarean delivery, preterm birth, and postpartum hemorrhage. Of all eligible singleton births, 846 124 (97.6%) were by unassisted conception, 16 087 (1.8%) by IVF, and 806 (0.1%) by gestational carriage. Respective risks for SMM were 2.3%, 4.3%, and 7.8%. The wRRs were 3.30 (95% CI, 2.59 to 4.20) comparing gestational carriage with unassisted conception and 1.86 (CI, 1.36 to 2.55) comparing gestational carriage with IVF. Respective risks for SNM were 5.9%, 8.9%, and 6.6%, generating wRRs of 1.20 (CI, 0.92 to 1.55) for gestational carriage versus unassisted conception and 0.81 (CI, 0.61 to 1.08) for gestational carriage versus IVF. Hypertensive disorders, postpartum hemorrhage, and preterm birth at less than 37 weeks were also significantly higher contrasting gestational carriers to either comparison group. Absence of information about indications for choosing a gestational carrier, and oocyte or sperm donor source. Among singleton births of more than 20 weeks' gestation, a higher risk for SMM and adverse pregnancy outcomes was seen among gestational carriers compared with women who conceived with and without assistance. Although gestational carriage was associated with preterm birth, there was less clear evidence of severe neonatal morbidity. Potential mechanisms for higher maternal morbidity among gestational carriers require elucidation, alongside developing special care plans for gestational carriers. The Canadian Institutes of Health Research.

Objective: To evaluate the risk of miscarriage following SARS‐CoV‐2 vaccination, while accounting for the competing risk of induced abortion.Design: Population‐based cohort study.Setting: Ontario, Canada.Participants: Women aged 15–50 years with a confirmed pregnancy at ≤19 completed weeks’ gestation.Methods: Exposure to first SARS‐CoV‐2 vaccination, handled in a time‐varying manner, was defined as (i) unvaccinated, (ii) remotely vaccinated >28 days before the estimated conception date or (iii) recently vaccinated ≤28 days before conception and up to 120 days after conception.Main outcome measures: The outcome was miscarriage, occurring between the estimated date of conception and up to 19 completed weeks of pregnancy. Fine‐Grey hazard models, accounting for the competing risk of induced abortion, generated hazard ratios (aHR), adjusted for socio‐demographic factors, comorbidities, and biweekly periods.Results: Included were 246 259 pregnant women, of whom 34% received a first SARS‐CoV‐2 vaccination. Miscarriage occurred at a rate of 3.6 per 10 000 person‐days among remotely vaccinated women and 3.2 per 10 000 person‐days among those recently vaccinated, in contrast to a rate of 1.9 per 10 000 person‐days among unvaccinated women, with corresponding aHR of 0.98 (95% confidence interval [CI] 0.91–1.07) and 1.00 (95% CI 0.93–1.08).Conclusions: SARS‐CoV‐2 vaccination was not associated with miscarriage while accounting for the competing risk of induced abortion. This study reiterates the importance of including pregnant women in new vaccine clinical trials and registries, and the rapid dissemination of vaccine safety data.

Background: Lung cancer (LC) is the leading cause of cancer-related mortality. In Ontario, Canada, there are significant survival differences for patients with newly diagnosed LC across the 14 provincial regions. Methods: A population-based retrospective cohort study using ICES databases from 01/2007–12/2017 identified patients with newly diagnosed LC through the Ontario Cancer Registry and those with LC as the cause of death. Descriptive data included patient, disease, and system characteristics. The primary outcome was 5-year survival by region. Results: 178,202 patient records were identified; 101,263 met inclusion criteria. LC incidence varied by region (5.6–14.6/10,000), as did histologic subtype (adenocarcinoma: 27.3–46.1%). Five-year cancer-specific survival was impacted by age, rurality, pathologic subtype, stage at diagnosis, and income quintile. Timely care was inversely related to survival (fastest quintile: HR 3.22, p < 0.0001). Adjusted 5-year cancer-specific survival varied across regions (24.1%, HR 1.12; 34.0%, HR 0.89, p < 0.001). Conclusions: When adjusting for confounders, differences in survival by health region persisted, suggesting a complex interplay between patient, disease, and system factors. A single approach to improving patient care is likely to be ineffective across different systems. Quality improvement initiatives to improve patient outcomes require different approaches amongst health regions to address local disparities in care.