International journal of epidemiology最新文献

Background: Disease latency is defined as the time from disease initiation to disease diagnosis. Disease latency bias (DLB) can arise in epidemiological studies that examine latent outcomes, since the exact timing of the disease inception is unknown and might occur before exposure initiation, potentially leading to bias. Although DLB can affect epidemiological studies that examine different types of chronic disease (e.g. Alzheimer's disease, cancer etc), the manner by which DLB can introduce bias into these studies has not been previously elucidated. Information on the specific types of bias, and their structure, that can arise secondary to DLB is critical for researchers, to enable better understanding and control for DLB.

Development: Here we describe four scenarios by which DLB can introduce bias (through different structures) into epidemiological studies that address latent outcomes, using directed acyclic graphs (DAGs). We also discuss potential strategies to better understand, examine and control for DLB in these studies.

Application: Using causal diagrams, we show that disease latency bias can affect results of epidemiological studies through: (i) unmeasured confounding; (ii) reverse causality; (iii) selection bias; (iv) bias through a mediator.

Conclusion: Disease latency bias is an important bias that can affect a number of epidemiological studies that address latent outcomes. Causal diagrams can assist researchers better identify and control for this bias.

Background: Despite persistent concerns about only children's disadvantage relative to individuals with siblings, existing health-related evidence is inconsistent. Recent evidence from Nordic countries about only children having poorer health outcomes may not apply elsewhere because selection processes differ across contexts. We investigate the midlife health of only children in the UK where one-child families tend to be socio-economically advantaged relative to large families.

Methods: Using the 1946, 1958 and 1970 British birth cohort studies, we examine various biomarkers and self-reported measures of chronic disease by sibship size when respondents are aged in their mid-40s, mid-50s and mid-60s. We estimate separate linear probability models for each cohort, age and outcome, adjusting for childhood and early adulthood circumstances.

Results: We found no evidence of only children differing from those with one, two or three or more siblings, at any age, in any of the cohorts, on: heart problems, hypertension, high triglycerides, high glycated haemoglobin or high C-reactive protein. However, compared with only children, the probability for cancer (0.019, 95% confidence interval [CI]: 0.002, 0.035; age 46/1970) and poor general health (0.060, CI: 0.015, 0.127; age 55/1958; and 0.110, CI: 0.052, 0.168; age 63/1946) was higher among those with three or more siblings.

Conclusions: There is no consistent pattern of only child health disadvantage for midlife chronic disease outcomes across ages or cohorts in the UK. Research should focus on better understanding how sibship size differentials are contingent on context.

Background: Autoimmune diseases disproportionately impact women and female-specific aspects of reproduction are thought to play a role. We investigated the time-varying association between pregnancy complications and new-onset autoimmune disease in females during the reproductive and midlife years.

Methods: We conducted a population-based cohort study of 1 704 553 singleton births to 1 072 445 females in Ontario, Canada (2002-17) with no pre-existing autoimmune disease. Pregnancy complications were preeclampsia, stillbirth, spontaneous preterm birth and severe small for gestational age (SGA). Royston-Parmar models were used to estimate the time-varying association between pregnancy complications and a composite of 25 autoimmune diseases from date of delivery to date of autoimmune disease diagnosis or censoring at death, loss of health insurance, or 31 March 2021. Models were adjusted for baseline socio-demographics, parity and comorbidities.

Results: At 19 years (median = 10.9 years of follow-up), cumulative incidence of autoimmune disease was 3.1% in those with a pregnancy complication and 2.6% in those without complications. Adjusted hazard ratio (AHR) curves as a function of time since birth were generally L-shaped. Universally, risks were most elevated within the first 3 years after birth [at 1 year: preeclampsia AHR 1.22, 95% confidence interval (CI) 1.09-1.36; stillbirth AHR 1.36, 95% CI 0.99-1.85; spontaneous preterm birth AHR 1.30, 95% CI 1.18-1.44; severe SGA AHR 1.14, 95% CI 0.99-1.31] and plateaued but remained elevated thereafter.

Conclusions: Prior history of pregnancy complications may be an important female-specific risk factor to consider during clinical assessment of females for possible autoimmune disease to facilitate timely detection and treatment.

Background: Heated tobacco products (HTPs) have emerged as alternatives to conventional cigarettes. However, their health effects remain largely unknown. This study aimed to prospectively explore the association between the use of cigarettes and HTPs and the risk of hypertension.

Methods: This cohort study analysed data from 30 152 workers (82.0% men, mean age 42.9 ± 11.0 years) who were initially free of hypertension, participating in the Japan Epidemiology Collaboration on Occupational Health Study. Participants were categorized into five groups based on their self-reported tobacco product use: never smokers, past smokers, exclusive cigarette smokers, exclusive HTP users and dual users of cigarettes and HTPs. Hypertension cases were identified using three data points from annual health checkup data collected between 2019 and 2021. Cox proportional hazards regression models were used to investigate the association between tobacco product use and hypertension.

Results: During a mean follow-up of 2.6 years (range: 0.1-4.0 years), 3656 new cases of hypertension were identified. Compared with never smokers, the risk of hypertension was higher among exclusive cigarette smokers [hazard ratio (HR) 1.26, 95% confidence interval (CI) 1.13-1.41] and exclusive HTP users (HR 1.19, 95% CI 1.06-1.34). There was also a suggestion of increased risk of hypertension among dual users (HR 1.16, 95% CI 0.98-1.38). Furthermore, the risk of hypertension increased with the intensity of cigarette/HTP use in all tobacco product users.

Conclusions: Similarly, both cigarette smoking and HTP use elevate the risk of hypertension. HTPs should not be regarded as less harmful alternatives to traditional cigarettes for preventing hypertension.

Background: Before the COVID-19 pandemic, stagnating life expectancy trends were reported in some high-income countries (HICs). Despite previous evidence from country-specific studies, there is a lack of comparative research that provides a broader perspective and challenges existing assumptions. This study aims to examine longevity trends and patterns in six English-speaking countries (Australia, Canada, Ireland, New Zealand, United Kingdom, United States) by combining period and cohort perspectives and to compare them with other HICs.

Methods: Using data from the Human Mortality and World Health Organization Mortality Databases, we estimated partial life expectancy, lifespan inequality and cohort survival differences for 1970-2021, as well as the contribution of causes of death to the gap in life expectancy between English-speaking countries and the average for other HICs in 2017-19.

Results: In the pre-pandemic period, the increase in life expectancy slowed in all English-speaking countries, except Ireland, mainly due to stagnating or rising mortality at young-middle ages. Relative to other HICs, those born in Anglophone countries since the 1970s experienced relative survival disadvantage, largely attributable to injuries (mainly suicides) and substance-related mortality (mainly poisonings). In contrast, older cohorts enjoyed advantages for females in Australia and Canada and for males in all English-speaking countries except the United States.

Conclusions: Although future gains in life expectancy in wealthy societies will increasingly depend on reducing mortality at older ages, adverse health trends at younger ages are a cause for concern. This emerging and avoidable threat to health equity in English-speaking countries should be the focus of further research and policy action.

Background: Older adults in the USA have worse health and wider socioeconomic inequalities in health compared with those in Britain. Less is known about how health in the two countries compares in mid-life, a time of emerging health decline, including inequalities in health.

Methods: We compare measures of current regular smoking status, obesity, self-rated health, cholesterol, blood pressure and glycated haemoglobin using population-weighted modified Poisson regression in the 1970 British Cohort Study (BCS70) in Britain (N = 9665) and the National Longitudinal Study of Adolescent to Adult Health (Add Health) in the USA (N = 12 300), when cohort members were aged 34-46 and 33-43, respectively. We test whether associations vary by early- and mid-life socioeconomic position.

Results: US adults had higher levels of obesity, high blood pressure and high cholesterol. Prevalence of poor self-rated health and current regular smoking was worse in Britain. We found smaller socioeconomic inequalities in mid-life health in Britain compared with the USA. For some outcomes (e.g. smoking), the most socioeconomically advantaged group in the USA was healthier than the equivalent group in Britain. For other outcomes (hypertension and cholesterol), the most advantaged US group fared equal to or worse than the most disadvantaged groups in Britain.

Conclusions: US adults have worse cardiometabolic health than British counterparts, even in early mid-life. The smaller socioeconomic inequalities and better overall health in Britain may reflect differences in access to health care, welfare systems or other environmental risk factors.