Pathway-specific population attributable fractions

Disease Prevalence ◽

Attributable Fractions ◽

Excessive Alcohol ◽

Relative Change ◽

AbstractA population attributable fraction (PAF) represents the relative change in disease prevalence that one might expect if a particular exposure was absent from the population. Often, one might be interested in what percentage of this effect acts through particular pathways. For instance, the effect of excessive alcohol intake on stroke risk may be mediated by blood pressure, body mass index and several other intermediate risk factors. In this situation, attributable fractions for each mediating pathway of interest can be defined as the relative change in disease prevalence from disabling the effect of the exposure through that mediating pathway.This quantity is related to, but distinct from the recently proposed metrics of direct and indirect PAF by Sjölander. In particular, while differing pathway-specific PAF will each usually be less than total PAF, they may sum over differing mediating pathways to more than total PAF, whereas direct and indirect PAF must sum to total PAF. Here, we present definitions, identifiability conditions and estimation approaches for pathway-specific attributable fractions. We illustrate results, and comparisons to indirect PAF using INTERSTROKE, a case-control study designed to quantify disease burden attributable to a number of known causal risk factors.

Risk factors for sporadicVibrio parahaemolyticusgastroenteritis in east China: a matched case-control study

Epidemiology and Infection ◽

10.1017/s0950268814001599 ◽

2014 ◽

Vol 143 (5) ◽

pp. 1020-1028 ◽

Cited By ~ 7

Author(s):

W. X. YAN ◽

Y. DAI ◽

Y. J. ZHOU ◽

H. LIU ◽

S. G. DUAN ◽

...

Keyword(s):

Risk Factors ◽

Case Control Study ◽

Multivariable Analysis ◽

Antibiotic Use ◽

Population Based ◽

Case Control ◽

Attributable Fractions ◽

Matched Case ◽

SUMMARYTo determine risk factors for sporadicVibrio parahaemolyticusgastroenteritis, we conducted a population-based case-control study in sentinel hospital surveillance areas of Shanghai and Jiangsu province, China. Seventy-one patients with diarrhoea and confirmedV. parahaemolyticusinfections were enrolled, and they were matched with 142 controls for gender, age and residential area. From the multivariable analysis,V. parahaemolyticusinfections were associated with antibiotics taken during the 4 weeks prior to illness [odds ratio (OR) 8·1, 95% confidence interval (CI) 1·2–56·4)], frequent eating out (OR 3·3, 95% CI 1·1–10·1), and shellfish consumption (OR 3·2, 95% CI 1·0–9·9), with population-attributable fractions of 0·09, 0·25, and 0·14, respectively. Protective factors included keeping the aquatic products refrigerated (OR 0·4, 95% CI 0·1–0·9) and pork consumption (OR 0·2, 95% CI 0·1–0·8). Further study of the association ofV. parahaemolyticusgastroenteritis with prior antibiotic use and shellfish consumption is needed.

1396. Risk Factors for Brain Abscess: A Nationwide Population-based Nested Case–Control Study

Open Forum Infectious Diseases ◽

10.1093/ofid/ofz360.1260 ◽

2019 ◽

Vol 6 (Supplement_2) ◽

pp. S507-S508

Author(s):

Jacob Bodilsen ◽

Michael Dalager-Pedersen ◽

Diederik van de Beek ◽

Matthijs C Brouwer ◽

Henrik Nielsen

Keyword(s):

Risk Factors ◽

Brain Abscess ◽

Case Control Study ◽

Population Based ◽

Case Control ◽

Attributable Fractions ◽

Nested Case Control ◽

Population Controls ◽

Abstract Background Knowledge of risk factors for brain abscess is limited and relies on single-center cohorts without control groups. Methods We accessed nationwide medical registries to conduct a population-based nested case–control study of risk factors for brain abscess. We applied risk set sampling for selection of population controls (1:10) individually matched by age, sex, and area of residence. Conditional logistic regression was used to compute adjusted odds ratios (aOR) with 95% confidence intervals (CIs). Next, population attributable fractions were calculated. Results We identified 1,384 brain abscess patients in Denmark from 1982 through 2016 and 13,839 matched population controls. The median age was 50 years (interquartile range 33–63) and 37% were female. Cases often had a Charlson comorbidity score>2 (16%) compared with controls (3%). Adjusted ORs were: head trauma 2.15 (1.72–2.70), neurosurgery 19.3 (14.3–26.0), dental infection 4.61 (3.39–6.26) or surgery 2.57 (1.71–3.84), ear-nose-throat infection 3.81 (3.11–4.67) or surgery 2.85 (2.21–3.70), congenital heart disease 15.6 (9.57–25.4), diabetes mellitus 1.74 (1.33–2.29), alcohol abuse 2.22 (1.58–3.11), liver disease 2.37 (1.53–3.68), kidney disease 2.04 (1.30–3.20), and lung abscess or bronchiectasis 8.15 (3.59–18.5). The aORs were 4.12 (3.37–5.04) and 8.77 (5.66–13.6) for solid and hematological cancer, 12.0 (6.13–23.7) for HIV, and 5.71 (4.22–7.75) for immuno-modulating treatments. Risks were twice as high when risk factors were observed within 5 years before brain abscess. Population attributable fractions showed that neurosurgery (12%), solid cancer (11%), ear-nose-throat infections (7%) and immuno-modulating treatments (5%) were substantial contributors to occurrence of brain abscess. Conclusion Important risk factors included neurosurgery, cancer, ear-nose-throat infections and immuno-modulating treatments Disclosures All authors: No reported disclosures.

Proportion of Orofacial Clefts Attributable to Recognized Risk Factors

The Cleft Palate-Craniofacial Journal ◽

10.1177/1055665618774019 ◽

2018 ◽

Vol 56 (2) ◽

pp. 151-158 ◽

Cited By ~ 5

Author(s):

Janhavi R. Raut ◽

Regina M. Simeone ◽

Sarah C. Tinker ◽

Mark A. Canfield ◽

R. Sue Day ◽

...

Keyword(s):

Risk Factors ◽

Cleft Palate ◽

Cleft Lip ◽

Attributable Fraction ◽

Individual Risk ◽

Orofacial Clefts ◽

Maternal Risk ◽

Attributable Fractions

Objective: Estimate the population attributable fraction (PAF) for a set of recognized risk factors for orofacial clefts. Design: We used data from the National Birth Defects Prevention Study. For recognized risk factors for which data were available, we estimated crude population attributable fractions (cPAFs) to account for potential confounding, average-adjusted population attributable fractions (aaPAFs). We assessed 11 modifiable and 3 nonmodifiable parental/maternal risk factors. The aaPAF for individual risk factors and the total aaPAF for the set of risk factors were calculated using a method described by Eide and Geffler. Setting: Population-based case–control study in 10 US states. Participants: Two thousand seven hundred seventy-nine cases with isolated cleft lip with or without cleft palate (CL±P), 1310 cases with isolated cleft palate (CP), and 11 692 controls with estimated dates of delivery between October 1, 1997, and December 31, 2011. Main Outcome Measures: Crude population attributable fraction and aaPAF. Results: The proportion of CL±P and CP cases attributable to the full set of examined risk factors was 50% and 43%, respectively. The modifiable factor with the largest aaPAF was smoking during the month before pregnancy or the first month of pregnancy (4.0% for CL±P and 3.4% for CP). Among nonmodifiable factors, the factor with the largest aaPAF for CL±P was male sex (27%) and for CP it was female sex (16%). Conclusions: Our results may inform research and prevention efforts. A large proportion of orofacial cleft risk is attributable to nonmodifiable factors; it is important to better understand the mechanisms involved for these factors.

Trends in the prevalence of airflow limitation in a general Japanese population: two serial cross-sectional surveys from the Hisayama Study

BMJ Open ◽

10.1136/bmjopen-2018-023673 ◽

2019 ◽

Vol 9 (3) ◽

pp. e023673

Author(s):

Hiroaki Ogata ◽

Yoichiro Hirakawa ◽

Koichiro Matsumoto ◽

Jun Hata ◽

Daigo Yoshida ◽

...

Keyword(s):

Risk Factors ◽

Airway Disease ◽

Population Based ◽

Forced Expiratory Volume ◽

Airflow Limitation ◽

Chronic Obstructive ◽

Cross Sectional ◽

Attributable Fractions

ObjectivesChronic obstructive airway disease, which is characterised by airflow limitation, is a major burden on public health. Reductions in environmental pollution in the atmosphere and workplace and a decline in the prevalence of smoking over recent decades may have affected the prevalence of airflow limitation in Japan. The present epidemiological study aimed to evaluate trends in the prevalence of airflow limitation and in the influence of risk factors on airflow limitation in a Japanese community.DesignTwo serial cross-sectional surveys.SettingData from the Hisayama Study, a population-based prospective study that has been longitudinally conducted since 1961.ParticipantsA total of 1842 and 3033 residents aged ≥40 years with proper spirometric measurements participated in the 1967 and 2012 surveys, respectively.Main outcome measuresAirflow limitation was defined as forced expiratory volume in 1 s/forced vital capacity <70% by spirometry. For each survey, the age-adjusted prevalence of airflow limitation was evaluated by sex. ORs and population attributable fractions of risk factors on the presence of airflow limitation were compared between surveys.ResultsThe age-standardised prevalence of airflow limitation decreased from 1967 to 2012 in both sexes (from 26.3% to 16.1% in men and from 19.8% to 10.5% in women). Smoking was significantly associated with higher likelihood of airflow limitation in both surveys, although the magnitude of its influence was greater in 2012 than in 1967 (the multivariable-adjusted OR was 1.63 (95% CI 1.19 to 2.24) in 1967 and 2.26 (95% CI 1.72 to 2.99) in 2012; p=0.007 for heterogeneity). Accordingly, the population attributable fraction of smoking on airflow limitation was 33.5% in 2012, which was 1.5-fold higher than that in 1967 (21.1%).ConclusionsThe prevalence of airflow limitation was decreased over 45 years in Japan, but the influence of smoking on airflow limitation increased with time.

Attributable is Preventable: Corrected and revised estimates of population attributable fraction of TB related to undernutrition in 30 high TB burden countries

10.1101/2021.12.09.21267540 ◽

2021 ◽

Author(s):

Anurag Bhargava ◽

Madhavi Bhargava ◽

Andrea Beneditti ◽

Anura Kurpad

Keyword(s):

Risk Factors ◽

Attributable Fraction ◽

Energy Availability ◽

Asian Countries ◽

High Burden ◽

Attributable Fractions ◽

Per Capita ◽

Corrected Estimate

AbstractIntroductionThe Global TB Report 2020 estimated the population attributable fractions (PAF) for the major risk factors of TB. Undernourishment emerged as the leading risk factor accounting for 19% of the cases. The WHO however used the terms undernourishment and undernutrition interchangeably in its computation of PAF. Undernourishment is an indirect model derived estimate of decreased per capita energy availability, while undernutrition is defined by direct anthropometric measurements of nutritional status.MethodsWe re-estimated the PAF of undernutrition (instead of undernourishment) in 30 high TB burden countries, using the prevalence of undernutrition (age standardized estimate of BMI < 18.5 kg/m2 in adults for both sexes), and the relative risk (RR) of 3.2. Further, we revised PAF estimates of undernutrition with an RR of 4.49, in light of recent evidence.FindingsTwenty four percent of TB in high burden countries is attributable to undernutrition. The PAF of undernutrition was highest in Asian countries, unlike the PAF of undernourishment that was highest in Africa. The corrected estimate led up to 65% increase in number of cases attributable to undernutrition in Asian countries. More than one-third to nearly half of TB cases in India could be attributable to undernutrition.InterpretationEstimation of the PAF of TB related to undernutrition is methodologically valid and operationally relevant, rather than PAF related to undernourishment. Addressing undernutrition, the leading driver of TB in high TB burden countries (especially Asia) could enable achievement of END TB milestones of TB incidence for 2025.

Risk Factors for Brain Abscess: A Nationwide, Population-Based, Nested Case-Control Study

Clinical Infectious Diseases ◽

10.1093/cid/ciz890 ◽

2019 ◽

Vol 71 (4) ◽

pp. 1040-1046 ◽

Cited By ~ 1

Author(s):

Jacob Bodilsen ◽

Michael Dalager-Pedersen ◽

Diederik van de Beek ◽

Matthijs C Brouwer ◽

Henrik Nielsen

Keyword(s):

Risk Factors ◽

Brain Abscess ◽

Population Based ◽

Solid Cancer ◽

Attributable Fractions ◽

Nested Case Control ◽

Population Controls ◽

Control Study ◽

Nose And Throat

Abstract Background Knowledge on risk factors for brain abscess is limited and relies on single-center cohort studies. Methods We accessed nationwide medical registries to conduct a population-based, nested case-control study of risk factors for brain abscess. We applied risk-set sampling for the selection of population controls (1:10), who were individually matched by age, sex, and area of residence. Conditional logistic regression was used to compute adjusted odds ratios (aOR) with 95% confidence intervals (CIs). Population-attributable fractions were calculated. Results We identified 1384 brain abscess patients in Denmark from 1982 through 2016, and 13 839 matched population controls. The median age of patients was 50 years (interquartile range 33–63) and 37% were female. Cases often had Charlson comorbidity scores >2 (16%), compared with controls (3%). Our calculated aORs were 2.15 (95% CI 1.72–2.70) for head trauma; 19.3 (95% CI 14.3–26.0) for neurosurgery; 4.61 (95% CI 3.39–6.26) for dental infections; 2.57 (95% CI 1.71–3.84) for dental surgery; 3.81 (95% CI 3.11–4.67) for ear, nose, and throat infection; 2.85 (95% CI 2.21–3.70) for ear, nose, and throat surgery; 15.6 (95% CI 9.57–25.4) for congenital heart disease; 1.74 (95% CI 1.33–2.29) for diabetes mellitus; 2.22 (95% CI 1.58–3.11) for alcohol abuse; 2.37 (95% CI 1.53–3.68) for liver disease; 2.04 (95% CI 1.30–3.20) for kidney disease and 8.15 (95% CI 3.59–18.5) for lung abscess or bronchiectasis. The aORs were 4.12 (95% CI 3.37–5.04) for solid cancer; 8.77 (95% CI 5.66–13.6) for hematological cancer; 12.0 (95% CI 6.13–23.7) for human immunodeficiency virus; and 5.71 (95% CI 4.22–7.75) for immunomodulating treatments. Population-attributable fractions showed were substantial contributors to the occurrence of brain abscess neurosurgery (12%); solid cancer (11%); ear, nose, and throat infections (7%); and immunomodulating treatments (5%). Conclusions Important risk factors included neurosurgery; cancer; ear, nose, and throat infections; and immunomodulating treatments.

Population attributable fraction for continuously distributed exposures

10.1101/2020.10.15.20212886 ◽

2020 ◽

Author(s):

John Ferguson ◽

Fabrizio Maturo ◽

Salim Yusuf ◽

Martin O’Donnell

Keyword(s):

Risk Factors ◽

Risk Factor ◽

Continuous Exposure ◽

Minimum Risk ◽

Graphical Comparison ◽

Attributable Fractions ◽

Potential Outcomes Framework ◽

Prior Risk

AbstractWhen estimating population attributable fractions (PAF), it is common to partition a naturally continuous exposure into a categorical risk factor. While prior risk factor categorization can help estimation and interpretation, it can result in underestimation of the disease burden attributable to the exposure as well as biased comparisons across different exposures and risk factors. Here, we propose sensible PAF estimands for continuous exposures under a potential outcomes framework. In contrast to previous approaches, we incorporate estimation of the minimum risk exposure value (MREV) into our procedures. While for exposures such as tobacco usage, a sensible value of the MREV is known, often it is unknown and needs to be estimated. Second, in the setting that the MREV value is an extreme-value of the exposure lying in the distributional tail, we argue that the natural estimator of PAF may be both statistically biased and highly volatile; instead, we consider a family of modified PAFs which include the natural estimate of PAF as a limit. A graphical comparison of this set of modified PAF for differing risk factors may be a better way to rank risk factors as intervention targets, compared to the standard PAF calculation. Finally, we analyse the bias that may ensue from prior risk factor categorization, examining whether categorization is ever a good idea, and suggest interpretations of categorized-estimands within a causal inference setting.

Population attributable fractions and joint effects of key risk factors for multiple sclerosis

Multiple Sclerosis Journal ◽

10.1177/1352458515594040 ◽

2015 ◽

Vol 22 (4) ◽

pp. 461-469 ◽

Cited By ~ 37

Author(s):

IAF van der Mei ◽

RM Lucas ◽

BV Taylor ◽

PC Valery ◽

T Dwyer ◽

...

Keyword(s):

Risk Factors ◽

Multiple Sclerosis ◽

Sun Exposure ◽

Population Based ◽

Attributable Fractions ◽

History Of ◽

Cns Demyelination ◽

Control Study ◽

Additive Scale

Aim: We examined the combined effect of having multiple key risk factors and the interactions between the key risk factors of multiple sclerosis (MS). Methods: We performed an incident case-control study including cases with a first clinical diagnosis of central nervous system demyelination (FCD) and population-based controls. Results: Compared to those without any risk factors, those with one, two, three, and four or five risk factors had increased odds of being an FCD case of 2.12 (95% confidence interval (CI), 1.11–4.03), 4.31 (95% CI, 2.24–8.31), 7.96 (95% CI, 3.84–16.49), and 21.24 (95% CI, 5.48–82.40), respectively. Only HLA-DR15 and history of infectious mononucleosis interacted significantly on the additive scale (Synergy index, 3.78; p = 0.03). The five key risk factors jointly accounted for 63.8% (95% CI, 43.9–91.4) of FCD onset. High anti-EBNA IgG was another important contributor. Conclusions: A high proportion of FCD onset can be explained by the currently known risk factors, with HLA-DR15, ever smoking and low cumulative sun exposure explaining most. We identified a significant interaction between HLA-DR15 and history of IM in predicting an FCD of CNS demyelination, which together with previous observations suggests that this is a true interaction.

Parental risk factors for congenital diaphragmatic hernia – a large German case-control study

BMC Pediatrics ◽

10.1186/s12887-021-02748-3 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Felicitas Schulz ◽

Ekkehart Jenetzky ◽

Nadine Zwink ◽

Charlotte Bendixen ◽

Florian Kipfmueller ◽

...

Keyword(s):

Risk Factors ◽

Confidence Interval ◽

Environmental Risk ◽

Odds Ratio ◽

Alcohol Intake ◽

Case Control Study ◽

Case Control ◽

Parental Risk Factors ◽

Healthy Control ◽

Abstract Background Evidence for periconceptional or prenatal environmental risk factors for the development of congenital diaphragmatic hernia (CDH) is still scarce. Here, in a case-control study we investigated potential environmental risk factors in 199 CDH patients compared to 597 healthy control newborns. Methods The following data was collected: time of conception and birth, maternal BMI, parental risk factors such as smoking, alcohol or drug intake, use of hairspray, contact to animals and parental chronic diseases. CDH patients were born between 2001 and 2019, all healthy control newborns were born in 2011. Patients and control newborns were matched in the ratio of three to one. Results Presence of CDH was significantly associated with maternal periconceptional alcohol intake (odds ratio = 1.639, 95% confidence interval 1.101–2.440, p = 0.015) and maternal periconceptional use of hairspray (odds ratio = 2.072, 95% confidence interval 1.330–3.229, p = 0.001). Conclusion Our study suggests an association between CDH and periconceptional maternal alcohol intake and periconceptional maternal use of hairspray. Besides the identification of novel and confirmation of previously described parental risk factors, our study underlines the multifactorial background of isolated CDH.