Background Australia provides a valuable international case study of life expectancy during the pandemic. In contrast to many other countries, it experienced relatively stringent restrictions and low COVID-19 mortality during 2020–21, followed by relaxation of these restrictions when high vaccination rates were achieved. This study measures Australia’s life expectancy trends and the contributions of

Background The effect of exposure to extreme temperature events (ETEs) on dementia mortality remains largely unknown. We aimed to quantify the association of ETE exposure with dementia mortality. Methods We conducted a population-based, case-crossover study among 57 791 dementia deaths in Jiangsu province, China, during 2015–20. Daily mean temperatures were extracted from a validated grid dataset at

Background COVID-19 vaccines have been shown to protect pregnant individuals against mild and severe COVID-19 outcomes. However, limited safety data are available for inactivated (CoronaVac) and mRNA (BNT162b2) vaccines during pregnancy regarding their effect on birth outcomes and neonatal mortality, especially in low- and middle-income countries. Methods We conducted a retrospective population-based

Motivation Providing a dynamic assessment of prognosis is essential for improved personalized medicine. The landmark model for survival data provides a potentially powerful solution to the dynamic prediction of disease progression. However, a general framework and a flexible implementation of the model that incorporates various outcomes, such as competing events, have been lacking. We present an R

Background We aimed to identify patterns within the rate of kidney function decline, determinants of these patterns and their association with all-cause mortality risk in the general population. Methods Participants aged ≥ 45 years with at least one assessment of creatinine-based estimated glomerular filtration rate (eGFR) taken between 1997 and 2018 were selected from a population-based cohort study

Background Individuals with major birth defects are at increased risk of developing cancer, indicating a common aetiology. However, whether the siblings of individuals with birth defects are also at an increased risk of cancer is unclear. Methods We used nationwide health registries in four Nordic countries and conducted a nested case-control study. We included 40 538 cancer cases (aged 0–46 years)

Background Evidence on the durability of the protection of a fourth dose of a monovalent or bivalent messenger ribonucleic acid (mRNA) vaccine against coronavirus disease 2019 (COVID-19) among older people during the predominant Omicron period is needed. Methods We performed a population-based cohort study in Norway covering the time from 1 July 2022 to 15 January 2023, including individuals ≥75 years

Background The emergence of SARS-CoV-2 affected urban areas. In Barcelona, six waves of COVID-19 hit the city between March 2020 and March 2022. Inequalities in the incidence of COVID-19 have been described. However, no studies have examined the daily trends of socioeconomic inequalities and how they changed during the different phases of the pandemic. The aim of this study is to analyse the dynamic

Background Cerebral palsy (CP) is the most common cause of childhood physical disability whose aetiology remains unclear in most cases. Maternal pre-existing and pregnancy complications are recognized risk factors of CP but the extent to which their effects are mediated by pre-term birth is unknown. Methods Population-based cohort study in Sweden including 2 055 378 singleton infants without congenital

Background This study aims to quantify Black–White inequities in cardiovascular disease (CVD) mortality among US survivors of 18 adult-onset cancers and the extent to which these inequities are explained by differences in socio-economic and clinical factors. Methods Survivors of cancers diagnosed at ages 20–64 years during 2007–16 were identified from 17 Surveillance, Epidemiology and End Results registries

Background On average, educated people are healthier, wealthier and have higher life expectancy than those with less education. Numerous studies have attempted to determine whether education causes differences in later health outcomes or whether another factor ultimately causes differences in education and subsequent outcomes. Previous studies have used a range of natural experiments to provide causal

Causal directed acyclic graphs (DAGs) are often used to select variables in a regression model to identify causal effects. Outcome-based sampling studies, such as the ‘test-negative design’ used to assess vaccine effectiveness, present unique challenges that are not addressed by the common back-door criterion. Here we discuss intuitive, graphical approaches to explain why the common back-door criterion

BACKGROUND The strong association of body mass index (BMI) with increased oesophageal adenocarcinoma risk is established, but its relationship with oesophageal squamous cell carcinoma is less clear. There is little evidence regarding the association of abdominal adiposity with either subtype. METHODS In a large prospective cohort of women in the UK, mean age 56.2 [standard deviation (SD) = 4.9] years

BACKGROUND Alcohol consumption is linked to decreased platelet function. Whether this link is dependent on sex or type of beverage remains unclear. METHODS Cross-sectional data were obtained from the Framingham Heart Study (N = 3427). Alcohol consumption was assessed by using standardized medical history and Harvard semi-quantitative food frequency questionnaires. Five bioassays measured 120 platelet

Background Understanding the differences in the burden of liver cancer due to different risk factors across provinces is critical to informing and improving liver cancer prevention and control. In this study, we estimated the population attributable fractions (PAFs) of liver cancer in all 31 provinces of China in 2016. Methods Prevalence estimates of risk factors were derived from representative surveys

Background The mechanisms underlying genetic predisposition to higher body mass index (BMI) remain unclear. Methods We hypothesized that the relationship between BMI-genetic risk score (BMI-GRS) and BMI was mediated via disinhibition, emotional eating and hunger, and moderated by flexible (but not rigid) restraint within two UK cohorts: the Genetics of Appetite Study (GATE) (n = 2101, 2010–16) and

BACKGROUND Seroprevalence and the proportion of people with neutralizing activity (functional immunity) against SARS-CoV-2 variants were high in early 2022. In this prospective, population- based, multi-region cohort study, we assessed the development of functional and hybrid immunity (induced by vaccination and infection) in the general population during this period of high incidence of infections

Background Mendelian randomization (MR) studies show iron positively associated with type 2 diabetes (T2D) but included potentially biasing hereditary haemochromatosis variants and did not assess reverse causality. Methods We assessed the relation of iron homeostasis with T2D and glycaemic traits bidirectionally, using genome-wide association studies (GWAS) of iron homeostasis biomarkers [ferritin

Background Shorter average lifespans for minoritized populations are hypothesized to stem from ‘weathering’ or accelerated health declines among minoritized individuals due to systemic marginalization. However, evidence is mixed on whether racial/ethnic differences exist in reproductive ageing, potentially due to selection biases in cohort studies that may systematically exclude ‘weathered’ participants

Background Preterm birth has been associated with increased risk of hypertension and cardiovascular disease later in adulthood, attributed to cardiovascular and metabolic alterations in early life. However, there is paucity of evidence from low- and middle-income countries (LMICs). Methods We investigated the differences between preterm (<37 weeks gestational age) and term-born individuals in birth

Background The extent to which known and unknown factors explain how much people of the same age differ in disease risk is fundamental to epidemiology. Risk factors can be correlated in relatives, so familial aspects of risk (genetic and non-genetic) must be considered. Development We present a unifying model (VALID) for variance in risk, with risk defined as log(incidence) or logit(cumulative incidence)

AIM A recent study has reported that anti-reflux surgery reduced the risk of lung cancer. However, the exact causal association between gastro-esophageal reflux disease (GORD) and lung cancer remains obscure. Therefore, we conducted a multivariable and network Mendelian randomization (MR) study to explore this potential association and mediation effect. METHODS Independent single nucleotide polymorphisms

Background Measurement error in exposures and confounders can bias exposure–outcome associations but is rarely considered. We aimed to assess random measurement error of all continuous variables in UK Biobank and explore approaches to mitigate its impact on exposure–outcome associations. Methods Random measurement error was assessed using intraclass correlation coefficients (ICCs) for all continuous

BACKGROUND Food intake plays a pivotal role in regulating circadian rhythms, which modulate glucose and lipid homeostasis. However, studies investigating the association of meal timing and type 2 diabetes (T2D) incidence are lacking. The objective of this study was to investigate the longitudinal associations of meal timing, number of eating occasions and night-time fasting duration with incidence

Prevalence estimates are fundamental to epidemiological studies. Although they are highly vulnerable to misclassification bias, the risk of bias assessment of prevalence estimates is often neglected. Quantitative bias analysis (QBA) can effectively estimate misclassification bias in epidemiological studies; however, relatively few applications are identified. One reason for its low usage is the lack

BACKGROUND Diabetes mellitus (DM) is a well-established risk factor for active tuberculosis (TB) infection. Despite the worldwide rapid increase in the prevalence of prediabetes, its impact on the risk of active TB remains largely unknown. This study aimed to investigate the relationship between prediabetes and risk of active TB in a large cohort study. METHODS A total of 119 352 participants were

BACKGROUND Whether changes in stroke mortality are affected by age distribution and birth cohorts, and if the decline in stroke mortality exhibits heterogeneity by stroke type, remains uncertain. METHODS We undertook a sequential time series analysis to examine stroke mortality trends in the USA among people aged 18-84 years between 1975 and 2019 (n = 4 332 220). Trends were examined for overall stroke

Background Aboriginal and Torres Strait Islander (hereafter Aboriginal) women have a high prevalence of diabetes in pregnancy (DIP), which includes pre-gestational diabetes mellitus (PGDM) and gestational diabetes mellitus (GDM). We aimed to characterize the impact of DIP in babies born to Aboriginal mothers. Methods A retrospective cohort study, using routinely collected linked health data that included

BACKGROUND The risk of solid cancers from low-level protracted ionizing radiation is not well characterized. Nuclear workers provide valuable information on the effects of ionizing radiation in contemporary exposure scenarios relevant to workers and the public. METHODS We evaluated the association between penetrating ionizing radiation exposure and solid cancer mortality among a pooled cohort of nuclear

Background Air pollution and gestational diabetes mellitus (GDM) are both associated with increased diabetes mellitus (DM) occurrence. However, whether air pollutants modify the effects of GDM on the occurrence of DM has been unknown. This study aims to determine whether the effect of GDM on DM development can be modified by exposure to ambient air pollutants. Methods Women with one singleton birth

Background Early puberty timing is associated with adverse health outcomes. We aimed to examine prospective associations between objectively measured physical activity and puberty timing in boys and girls. Methods In the UK Millennium Cohort Study, physical activity volume and intensities at 7 years were measured using accelerometers. Status of several pubertal traits and age at menarche were reported

Not only do cluster randomized trials require a larger sample size than individually randomized trials, they also face many additional complexities. The potential for contamination is the most commonly used justification for using cluster randomization, but the risk of contamination should be carefully weighed against the more serious problem of questionable scientific validity in settings with post-randomization

It is well-known that designing a cluster randomized trial (CRT) requires an advance estimate of the intra-cluster correlation coefficient (ICC). In the case of longitudinal CRTs, where outcomes are assessed repeatedly in each cluster over time, estimates for more complex correlation structures are required. Three common types of correlation structures for longitudinal CRTs are exchangeable, nested/block

Background The burden of chronic conditions associated with sugary beverages is increasing but little is known about the role of different types of sugary beverages in the co-occurrence of multiple chronic conditions (‘multimorbidity’). To inform future sugar-reduction guidelines, we aimed to examine the associations of sugar-sweetened beverages (SSB), artificially sweetened beverages (ASB) and natural

Background Season of birth has been associated with age at menarche. Maternal vitamin D levels in pregnancy may explain this effect. We investigated whether the season of first trimester or maternal 25-hydroxyvitamin D3 [25(OH)D3] levels were associated with pubertal timing in children. Methods We conducted a follow-up study of 15 819 children born in 2000–03 from the Puberty Cohort, nested in the

Background Immeasurable time bias arises from the lack of in-hospital medication information. It has been suggested that time-varying adjustment for hospitalization may minimize this potential bias. However, whereas we examined this issue in one case study, there remains a need to assess the validity of this approach in other settings. Methods Using a Monte Carlo simulation, we generated synthetic

Background Reliable and detailed data on the prevalence of tuberculosis (TB) with sub-national estimates are scarce in Ethiopia. We address this knowledge gap by spatially predicting the national, sub-national and local prevalence of TB, and identifying drivers of TB prevalence across the country. Methods TB prevalence data were obtained from the Ethiopia national TB prevalence survey and from a comprehensive

Background We investigated whether military personnel involved in chemical warfare agent research at Porton Down had increased rates of mortality or cancer incidence. Methods This was a historical cohort study comprising male UK veterans who participated in the ‘Service Volunteer Programme’, 1941–89, identified from Porton Down experiment books, and a comparison group of similar ‘non-Porton Down’ veterans

Background The associations between fine and coarse particulate matter (PM2.5 and PM2.5–10) air pollution and hospital admissions for full-spectrum respiratory diseases were rarely investigated, especially for age-specific associations. We aim to estimate the age-specific associations of short-term exposures to PM2.5 and PM2.5–10 with hospital admissions for full-spectrum respiratory diseases in China

Background Child marriage, defined as marriage under the age of 18 years, remains pervasive in India. Global evidence documents a negative association between child marriage and women's reproductive and sexual health outcomes; however, its relationship with non-communicable diseases (NCDs) remains underexplored. Methods We utilize biomarkers and self-reported data from the nationally representative

Background Many countries have been increasing their state pension age (SPA); nonetheless, there is little consensus on whether retirement affects the risk of cardiovascular disease (CVD). This study examined the associations of retirement with CVD and risk factors. Methods We used harmonized longitudinal datasets from the Health and Retirement Study and its sister surveys in 35 countries. Data comprised

Background Adverse childhood experiences (ACEs) are a risk factor for obesity; however, the causal mechanisms are not well understood. Objectives were to measure the impact of ACEs on adulthood obesity and to investigate whether the association was mediated by nutrition and stress. Methods A longitudinal study was conducted using adults aged 46–90 years (n = 26 615) from the Canadian Longitudinal Study

Systematic error from selection bias, uncontrolled confounding, and misclassification is ubiquitous in epidemiologic research but is rarely quantified using quantitative bias analysis (QBA). This gap may in part be due to the lack of readily modifiable software to implement these methods. Our objective is to provide computing code that can be tailored to an analyst’s dataset. We briefly describe the

Background Acute bacterial meningitis (ABM) is a serious health issue in Yemen where civil war, which continues unabated, has crippled the healthcare system. We conducted a nationwide retrospective observational study in Yemeni sentinel hospitals to identify the prevalence, aetiology, vaccination coverage and spatio-temporal pattern of ABM in children aged <5 years before and during the civil war,