International journal of epidemiology最新文献

Background: The role of children and staff in SARS-CoV-2 transmission outside and within households is still not fully understood when large numbers are in regular, frequent contact in schools.

Methods: We used the self-controlled case-series method during the alpha- and delta-dominant periods to explore the incidence of infection in periods around a household member infection, relative to periods without household infection, in a cohort of primary and secondary English schoolchildren and staff from November 2020 to July 2021.

Results: We found the relative incidence of infection in students and staff was highest in the 1-7 days following household infection, remaining high up to 14 days after, with risk also elevated in the 6--12 days before household infection. Younger students had a higher relative incidence following household infection, suggesting household transmission may play a more prominent role compared with older students. The relative incidence was also higher among students in the alpha variant dominant period.

Conclusions: This analysis suggests SARS-CoV2 infection in children, young people and staff at English schools were more likely to be associated with within-household transmission than from outside the household, but that a small increased risk of seeding from outside is observed.

Background: Biomass burning (BB) is a major source of air pollution and particulate matter (PM) in Southeast Asia. However, the health effects of PM smaller than 10 µm (PM10) originating from BB may differ from those of other sources. This study aimed to estimate the short-term association of PM10 from BB with respiratory and cardiovascular hospital admissions in Peninsular Malaysia, a region often exposed to BB events.

Methods: We obtained and analyzed daily data on hospital admissions, PM10 levels and BB days from five districts from 2005 to 2015. We identified BB days by evaluating the BB hotspots and backward wind trajectories. We estimated PM10 attributable to BB from the excess of the moving average of PM10 during days without BB hotspots. We fitted time-series quasi-Poisson regression models for each district and pooled them using meta-analyses. We adjusted for potential confounders and examined the lagged effects up to 3 days, and potential effect modification by age and sex.

Results: We analyzed 210 960 respiratory and 178 952 cardiovascular admissions. Almost 50% of days were identified as BB days, with a mean PM10 level of 53.1 µg/m3 during BB days and 40.1 µg/m3 during normal days. A 10 µg/m3 increment in PM10 from BB was associated with a 0.44% (95% CI: 0.06, 0.82%) increase in respiratory admissions at lag 0-1, with a stronger association in adults aged 15-64 years and females. We did not see any significant associations for cardiovascular admissions.

Conclusions: Our findings suggest that short-term exposure to PM10 from BB increased the risk of respiratory hospitalizations in Peninsular Malaysia.

Background: Homicide is the leading cause of death among young people in Latin America, one of the world's most violent regions. Poverty is widely considered a key cause of violence, but theories suggest different effects of poverty, depending on when it is experienced in the life-course. Longitudinal studies of violence are scarce in Latin America, and very few prospective data are available worldwide to test different life-course influences on homicide.

Methods: In a prospective birth cohort study following 5914 children born in southern Brazil, we examined the role of poverty at birth, in early childhood, and in early adulthood on violence and homicide perpetration, in criminal records up to age 30 years. A novel Structured Life Course Modelling Approach was used to test competing life-course hypotheses about 'sensitive periods', 'accumulation of risk', and 'downward mobility' regarding the influence of poverty on violence and homicide.

Results: Cumulative poverty and poverty in early adulthood were the most important influences on violence and homicide perpetration. This supports the hypothesis that early adulthood is a sensitive period for the influence of poverty on lethal and non-lethal violence. Results were replicable using different definitions of poverty and an alternative outcome of self-reported fights.

Conclusion: Cumulative poverty from childhood to adulthood was an important driver of violence and homicide in this population. However, poverty experienced in early adulthood was especially influential, suggesting the importance of proximal mechanisms for violence in this context, such as unemployment, organized crime, drug trafficking, and ineffective policing and justice systems.

Background: Epithelial ovarian cancer (EOC) is the eighth most common cancer in women, with poor survival outcomes. Observational evidence suggests that nitrogen-based bisphosphonate (NBB) use may be associated with reduced risk of EOC, particularly the endometrioid and serous histotypes; however, confounding by indication is a concern. An alternative approach to investigate the chemo-preventive potential of NBBs is to emulate a target trial by identifying all women who initiate use of NBBs and investigate the risk of EOC for continued users compared with discontinued users.

Methods: Using population-based linked data, we identified all Australian women aged over 50 years who first used NBBs over 2004-12. We used the year after first use to define treatment for each woman as either continued or discontinued use. We emulated randomization using stabilized inverse probability weights to balance the treatment groups using covariates including age, comorbidities and socioeconomic status. We followed women from treatment assignment until EOC diagnosis, death or 31 December 2013. We assessed the risk of EOC (overall and by histotype) using flexible parametric time-to-event models allowing for time-varying effects, and produced time-varying coefficients.

Results: Of the 313 383 women in the study, 472 were diagnosed with EOC during follow-up (261 serous EOC), with an average age at diagnosis of 72 years. Continued use of NBBs was associated with reduced risk of EOC overall (HR = 0.87, 95% CI: 0.69, 1.10), and serous EOC (HR = 0.71, 95% CI: 0.53, 0.96), compared with discontinued treatment, with estimates remaining constant over the 9-year follow-up.

Conclusions: Results from our emulated trial suggest that in women who initiated NBB treatment, those who continued use had 13% and 29% lower hazards of being diagnosed with EOC overall and serous EOC, respectively, compared with women who discontinued use.