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The population-attributable fraction (PAF) is commonly interpreted as the proportion of events that can be ascribed to a certain exposure in a certain population. Its estimation is sensitive to common forms of time-dependent bias in the face of a time-dependent exposure. Predominant estimation approaches based on multistate modeling fail to fully eliminate such bias and, as a result, do not permit a causal interpretation, even in the absence of confounding. While recently proposed multistate modeling approaches can successfully eliminate residual time-dependent bias, and moreover succeed to adjust for time-dependent confounding by means of inverse probability of censoring weighting, inadequate application, and misinterpretation prevails in the medical literature. In this paper, we therefore revisit recent work on previously proposed PAF estimands and estimators in settings with time-dependent exposures and competing events and extend this work in several ways. First, we critically revisit the interpretation and applied terminology of these estimands. Second, we further formalize the assumptions under which a causally interpretable PAF estimand can be identified and provide analogous weighting-based representations of the identifying functionals of other proposed estimands. This representation aims to enhance the applied statistician's understanding of different sources of bias that may arise when the aim is to obtain a valid estimate of a causally interpretable PAF. To illustrate and compare these representations, we present a real-life application to observational data from the Ghent University Hospital ICUs to estimate the fraction of ICU deaths attributable to hospital-acquired infections., (© 2023 John Wiley & Sons Ltd.)

Abstract The 2011 EFSA opinion on Campylobacter was updated using more recent scientific data. The relative risk reduction in EU human campylobacteriosis attributable to broiler meat was estimated for on‐farm control options using Population Attributable Fractions (PAF) for interventions that reduce Campylobacter flock prevalence, updating the modelling approach for interventions that reduce caecal concentrations and reviewing scientific literature. According to the PAF analyses calculated for six control options, the mean relative risk reductions that could be achieved by adoption of each of these six control options individually are estimated to be substantial but the width of the confidence intervals of all control options indicates a high degree of uncertainty in the specific risk reduction potentials. The updated model resulted in lower estimates of impact than the model used in the previous opinion. A 3‐log10 reduction in broiler caecal concentrations was estimated to reduce the relative EU risk of human campylobacteriosis attributable to broiler meat by 58% compared to an estimate larger than 90% in the previous opinion. Expert Knowledge Elicitation was used to rank control options, for weighting and integrating different evidence streams and assess uncertainties. Medians of the relative risk reductions of selected control options had largely overlapping probability intervals, so the rank order was uncertain: vaccination 27% (90% probability interval (PI) 4–74%); feed and water additives 24% (90% PI 4–60%); discontinued thinning 18% (90% PI 5–65%); employing few and well‐trained staff 16% (90% PI 5–45%); avoiding drinkers that allow standing water 15% (90% PI 4–53%); addition of disinfectants to drinking water 14% (90% PI 3–36%); hygienic anterooms 12% (90% PI 3–50%); designated tools per broiler house 7% (90% PI 1–18%). It is not possible to quantify the effects of combined control activities because the evidence‐derived estimates are inter‐dependent and there is a high level of uncertainty associated with each.

Background High sodium intake elevates blood pressure and thereby raises cardiovascular diseases (CVDs). Sodium intake is high in northern China, including Shandong province where the SMASH (Shandong‐Ministry of Health Action on Sodium and Hypertension) is currently underway. Methods and Results Blood pressure values and sodium intake measurements using 24‐hour urinary excretion were collected from the 2011 SMASH baseline survey, which was conducted in 20 counties/districts using a multistage stratified cluster random sampling method. We derived cause‐specific mortality from the Shandong Death Registration System (SDRS) during the same year and used population‐attributable fraction to estimate annual CVDs deaths attributable to high sodium intake (mediated through elevated systolic blood pressure) and CVD deaths averted by achieving different sodium‐reduction targets. Overall, 16 100 (95% uncertainty intervals, 11 000–22 600) CVD deaths among adults aged 25 to 69 years, including 5600 (4000–6500) for ischemic heart disease and 9000 (6700–11 600) for stroke, were attributable to higher sodium intake (2000 mg/day or 5.0 g/day of salt as a reference) in Shandong in 2011, accounting for 19.9% (13.7–25.0%) of total CVD deaths. The benefit of CVD deaths from sodium reduction is considerable with 8800 (6400–13 600), 6700 (4900–11 600), and 8500 (6000–10 800) averted, respectively, if sodium intake was reduced from the 2011 baseline to 3500 mg/day, 4000 mg/day, or reduced by 30%. Conclusions Nearly 20% of CVD deaths among adults aged 25 to 69 years could be attributable to the systolic blood pressure–raising effect of high sodium intake in Shandong in 2011. Potential benefits from population reduction of sodium intake are considerable.

Background: Human papillomavirus (HPV) is associated with a substantial percentage of cervical cancer, and a significant percentage of anal, penile, vaginal, vulvar, oral cavity, oropharyngeal, and laryngeal cancers. Understanding the burden and trends of HPV-attributable cancers is crucial to HPV prevention strategies. In the current study, the authors estimated the latest burden and trends of HPV-attributable cancers in China., Methods: Data from the following sources were used. The number of new cancer cases and cancer deaths in China were estimated based on the China Cancer Registry Annual Report. The population-attributable fraction was estimated using pooled high-risk HPV prevalence and biomarker-positive rates, which were calculated using random effects meta-analyses. Cancer burden estimates were stratified by anatomic site, sex, and age., Results: In 2015, a total of 110,650 new cancer cases and 36,714 cancer deaths attributable to HPV infection were estimated to have occurred in China, of which cervical cancer accounted for 85.6% and 78.1%, respectively. The age-standardized incidence rate (ASIR) and age-standardized mortality rate (ASMR) of HPV-attributable cancers were 5.63 and 1.81 per 100,000 person-years, respectively. The ASIR and ASMR both varied by anatomic site, with the highest rates noted for cervical cancer at 4.83 and 1.42 per 100,000 person-years, respectively. Between 2005 and 2015, the ASIR and ASMR demonstrated significant upward trends for all HPV-attributable cancers combined., Conclusions: Between 2005 and 2015, cervical cancer accounted for the vast majority of HPV-attributable cancers and its incidence and mortality increased rapidly in China. The comprehensive prevention of cervical cancer remains the most important target in the prevention of HPV-attributable cancers., (© 2020 American Cancer Society.)

The prevalence of excess body weight and the associated cancer burden have been rising over the past several decades globally. Between 1975 and 2016, the prevalence of excess body weight in adults-defined as a body mass index (BMI) ≥ 25 kg/m 2 -increased from nearly 21% in men and 24% in women to approximately 40% in both sexes. Notably, the prevalence of obesity (BMI ≥ 30 kg/m 2 ) quadrupled in men, from 3% to 12%, and more than doubled in women, from 7% to 16%. This change, combined with population growth, resulted in a more than 6-fold increase in the number of obese adults, from 100 to 671 million. The largest absolute increase in obesity occurred among men and boys in high-income Western countries and among women and girls in Central Asia, the Middle East, and North Africa. The simultaneous rise in excess body weight in almost all countries is thought to be driven largely by changes in the global food system, which promotes energy-dense, nutrient-poor foods, alongside reduced opportunities for physical activity. In 2012, excess body weight accounted for approximately 3.9% of all cancers (544,300 cases) with proportion varying from less than 1% in low-income countries to 7% or 8% in some high-income Western countries and in Middle Eastern and Northern African countries. The attributable burden by sex was higher for women (368,500 cases) than for men (175,800 cases). Given the pandemic proportion of excess body weight in high-income countries and the increasing prevalence in low- and middle-income countries, the global cancer burden attributable to this condition is likely to increase in the future. There is emerging consensus on opportunities for obesity control through the multisectoral coordinated implementation of core policy actions to promote an environment conducive to a healthy diet and active living. The rapid increase in both the prevalence of excess body weight and the associated cancer burden highlights the need for a rejuvenated focus on identifying, implementing, and evaluating interventions to prevent and control excess body weight., (© 2018 American Cancer Society.)

Contemporary information on the fraction of cancers that potentially could be prevented is useful for priority setting in cancer prevention and control. Herein, the authors estimate the proportion and number of invasive cancer cases and deaths, overall (excluding nonmelanoma skin cancers) and for 26 cancer types, in adults aged 30 years and older in the United States in 2014, that were attributable to major, potentially modifiable exposures (cigarette smoking; secondhand smoke; excess body weight; alcohol intake; consumption of red and processed meat; low consumption of fruits/vegetables, dietary fiber, and dietary calcium; physical inactivity; ultraviolet radiation; and 6 cancer-associated infections). The numbers of cancer cases were obtained from the Centers for Disease Control and Prevention (CDC) and the National Cancer Institute; the numbers of deaths were obtained from the CDC; risk factor prevalence estimates were obtained from nationally representative surveys; and associated relative risks of cancer were obtained from published, large-scale pooled analyses or meta-analyses. In the United States in 2014, an estimated 42.0% of all incident cancers (659,640 of 1570,975 cancers, excluding nonmelanoma skin cancers) and 45.1% of cancer deaths (265,150 of 587,521 deaths) were attributable to evaluated risk factors. Cigarette smoking accounted for the highest proportion of cancer cases (19.0%; 298,970 cases) and deaths (28.8%; 169,180 deaths), followed by excess body weight (7.8% and 6.5%, respectively) and alcohol intake (5.6% and 4.0%, respectively). Lung cancer had the highest number of cancers (184,970 cases) and deaths (132,960 deaths) attributable to evaluated risk factors, followed by colorectal cancer (76,910 cases and 28,290 deaths). These results, however, may underestimate the overall proportion of cancers attributable to modifiable factors, because the impact of all established risk factors could not be quantified, and many likely modifiable risk factors are not yet firmly established as causal. Nevertheless, these findings underscore the vast potential for reducing cancer morbidity and mortality through broad and equitable implementation of known preventive measures. CA Cancer J Clin 2018;68:31-54. © 2017 American Cancer Society., (© 2017 American Cancer Society.)