Errors in the Calculation of the Population Attributable Fraction.

One of the common errors in the calculation of the population attributable fraction (PAF) is the use of an adjusted risk ratio in the Levin formula. In this article, we discuss the errors visually using wireframes by varying the standardized mortality ratio (SMR) and associational risk ratio (aRR) when the prevalence of exposure is fixed. When SMR > 1 and SMR > aRR, the absolute bias is positive, and its magnitude increases as the difference between SMR and aRR increases. By contrast, when aRR > SMR > 1, the absolute bias is negative and its magnitude is relatively small. Moreover, when SMR > aRR, the relative bias is larger than 1, whereas when SMR < aRR, the relative bias is smaller than 1. Although the target population of the PAF is the total population, the target of causation of the PAF is not the total population but the exposed group.

Genetic architecture of alcohol consumption identified by a genotype-stratified GWAS and impact on esophageal cancer risk in Japanese people.

An East Asian-specific variant on aldehyde dehydrogenase 2 (ALDH2 rs671, G>A) is the major genetic determinant of alcohol consumption. We performed an rs671 genotype-stratified genome-wide association study meta-analysis of alcohol consumption in 175,672 Japanese individuals to explore gene-gene interactions with rs671 behind drinking behavior. The analysis identified three genome-wide significant loci (GCKR, KLB, and ADH1B) in wild-type homozygotes and six (GCKR, ADH1B, ALDH1B1, ALDH1A1, ALDH2, and GOT2) in heterozygotes, with five showing genome-wide significant interaction with rs671. Genetic correlation analyses revealed ancestry-specific genetic architecture in heterozygotes. Of the discovered loci, four (GCKR, ADH1B, ALDH1A1, and ALDH2) were suggested to interact with rs671 in the risk of esophageal cancer, a representative alcohol-related disease. Our results identify the genotype-specific genetic architecture of alcohol consumption and reveal its potential impact on alcohol-related disease risk.

Prenatal Exposure to Opioids and Neurodevelopmental Disorders in Children: A Bayesian Mediation Analysis.

This study explores natural direct and joint natural indirect effects (JNIE) of prenatal opioid exposure on neurodevelopmental disorders (NDDs) in children mediated through pregnancy complications, major and minor congenital malformations, and adverse neonatal outcomes, using Medicaid claims linked to vital statistics in Rhode Island, United States, 2008-2018. A Bayesian mediation analysis with elastic net shrinkage prior was developed to estimate mean time to NDD diagnosis ratio using posterior mean and 95% credible intervals (CrIs) from Markov chain Monte Carlo algorithms. Simulation studies showed desirable model performance. Of 11,176 eligible pregnancies, 332 had ≥2 dispensations of prescription opioids anytime during pregnancy, including 200 (1.8%) having ≥1 dispensation in the first trimester (T1), 169 (1.5%) in the second (T2), and 153 (1.4%) in the third (T3). A significant JNIE of opioid exposure was observed in each trimester (T1, JNIE = 0.97, 95% CrI: 0.95, 0.99; T2, JNIE = 0.97, 95% CrI: 0.95, 0.99; T3, JNIE = 0.96, 95% CrI: 0.94, 0.99). The proportion of JNIE in each trimester was 17.9% (T1), 22.4% (T2), and 56.3% (T3). In conclusion, adverse pregnancy and birth outcomes jointly mediated the association between prenatal opioid exposure and accelerated time to NDD diagnosis. The proportion of JNIE increased as the timing of opioid exposure approached delivery.

Staged repair for complete atrioventricular septal defect in patients weighing less than 4.0 kg.

OBJECTIVE: This study compared the mortality, left atrioventricular valve-related reoperation, and left atrioventricular valve competence in symptomatic neonates and small infants who underwent staged repair incorporating pulmonary artery banding or primary repair for complete atrioventricular septal defect. METHODS: Patients weighing less than 4.0 kg at the time of undergoing staged (n = 37) or primary (n = 23) repair for balanced complete atrioventricular septal defect between 1999 and 2022 were reviewed. The mean follow-up period was 9.1 years. Freedom from moderate or greater left atrioventricular valve regurgitation was estimated with the Kaplan-Meier method. RESULTS: The staged group included smaller children (median weight, 2.9 vs 3.7 kg) and a higher proportion of neonates (41% vs 4%). All patients in the staged group survived pulmonary artery banding and underwent intracardiac repair (median weight, 6.8 kg). After pulmonary artery banding, the severity of left atrioventricular valve regurgitation improved in 10 of 12 patients (83%) without left atrioventricular valve anomaly who had mild or greater left atrioventricular valve regurgitation and a left atrioventricular valve Z score greater than 0. Although survival and freedom from left atrioventricular valve-related reoperation at 15 years (P = .195 and .602, respectively) were comparable between the groups, freedom from moderate or greater left atrioventricular valve regurgitation at 15 years was higher in the staged group (P = .026). CONCLUSIONS: Compared with primary repair, staged repair for complete atrioventricular septal defect in children weighing less than 4.0 kg resulted in comparable survival and reoperation rates and better left atrioventricular valve competence. Pulmonary artery banding may mitigate secondary left atrioventricular valve regurgitation unless a structural valve abnormality exists. Selective deferred intracardiac repair beyond the neonatal and small-infancy period may still play an important role in low-weight patients.

Complementary and Alternative Medicine Use, Cancer Screening, and Medical Checkups in Japan from 2001 to 2013: A Repeated Cross-Sectional Study.

Introduction: The association between complementary and alternative medicine (CAM) use and other health-related behaviors is an important issue. A previous study reported that complementary medicine use is related to greater use of cancer screening, whereas alternative medicine use is related to lower use of cancer screening. Given the sparse evidence from Japan, we aimed to examine the association of CAM use with cancer screening and medical checkups. We used a repeated cross-sectional survey of a nationally representative sample of Japanese people and conducted age-period-cohort analysis. Methods: The study population was 68,217 of 83,827 individuals observed from 2001 to 2013 who received cancer screening. CAM users were defined as individuals who received acupuncture, moxibustion, anma/massage/shiatsu, or judo therapy for their most worrisome symptom. The outcomes of interest were receiving stomach, lung, colorectal, uterine, and breast cancer screenings and medical checkups. Using crossclassified multilevel logistic regression models, we estimated odds ratios (ORs) and 95% credible intervals (CIs) for cancer screening and medical checkups. Results: For CAM users of complementary medicine, the adjusted ORs for stomach, lung, and colorectal cancer screening were 1.40 (95% CI: 1.35-1.44), 1.37 (95% CI: 1.34-1.40), and 1.52 (95% CI: 1.49-1.54), respectively. We found similar results for uterine and breast cancer screening, and medical checkups. Conclusions: Irrespective of whether they use CAM, CAM users in Japan tend to receive a variety of cancer screenings and medical checkups.

Fine Particulate Matter and Diabetes Prevalence in Okayama, Japan.

Many studies have shown an association between long-term exposure to particulate matter having an aerodynamic diameter of 2.5 µm or less (PM2.5) and diabetes mellitus (DM), but few studies have focused on Asian subjects. We thus examined the association between long-term exposure to PM2.5 and DM prevalence in Okayama City, Japan. We included 76,591 participants who had received basic health checkups in 2006 and 2007. We assigned the census-level modeled PM2.5 data from 2006 and 2007 to each participant and defined DM using treatment status and the blood testing. PM2.5 was associated with DM prevalence, and the prevalence ratio (95% confidence interval) was 1.10 (1.00-1.20) following each interquartile range increase (2.1 µg/m3) in PM2.5. This finding is consistent with previous results and suggests that long-term exposure to PM2.5 is associated with an increased prevalence of DM in Okayama City, Japan, where the PM2.5 level is lower than in other cities in Asian countries.

A population-based longitudinal study on glycated hemoglobin levels and new-onset chronic kidney disease among non-diabetic Japanese adults.

Chronic kidney disease (CKD) is a major global public health problem. Recent studies reported that diabetes and prediabetes are risk factors for developing CKD; however, the exact glycated hemoglobin (HbA1c) cut-off value for prediabetes remains controversial. In this study, we aimed to examine the relationship between HbA1c levels and subsequent CKD development in greater detail than previous studies. Longitudinal data of annual checkups of 7176 Japanese non-diabetic people (male: 40.4%) from 1998 to 2022 was analyzed. HbA1c values were categorized into < 5.0%, 5.0-5.4%, 5.5-5.9%, and 6.0-6.4%. CKD was defined as an estimated glomerular filtration rate < 60 ml/min/1.73 m2. The descriptive statistics at study entry showed that higher HbA1c values were associated with male, older, overweight or obese, hypertensive, or dyslipidemic people. During a mean follow-up of 7.75 person-years, 2374 participants (male: 40.0%) developed CKD. The Weibull accelerated failure time model was selected because the proportional hazards assumption was violated. The adjusted time ratios of developing CKD for HbA1c levels of 5.5-5.9% and 6.0-6.4% compared with 5.0-5.4% were 0.97 (95% confidence interval: 0.92-1.03) and 1.01 (95% confidence interval: 0.90-1.13), respectively. There was no association between HbA1c in the prediabetic range and subsequent CKD development.

Accuracy of ultrasound vs. Fourier-domain optic biometry for measuring preoperative axial length in cases of rhegmatogenous retinal detachment.

PURPOSE: To identify a method for accurately measuring preoperative axial length (AL) in cases of rhegmatogenous retinal detachment (RRD). STUDY DESIGN: Retrospective study. METHODS: This retrospective study included 83 eyes of 83 patients who underwent vitrectomy for RRD and had both preoperative and postoperative data for AL. Preoperative AL measurements for the affected eye were obtained using ultrasound (aUS-AL) and compared with those for affected and fellow eyes measured using optical biometry (aOB-AL and fOB-AL, respectively). Absolute differences between preoperative aUS-AL, aOB-AL, or fOB-AL measurements and postoperative AL (aPost-AL) were examined. RESULTS: In the 41 eyes without macular detachment, the absolute difference between aOB-AL and aPost-AL (0.06±0.07 mm) was significantly smaller than between aUS-AL and aPost-AL (0.21±0.18 mm) and that between fOB-AL and aPost-AL (0.29±0.35 mm) (P = 0.017 and P < 0.001, respectively). In the 42 eyes with macular detachment, the absolute difference between aOB-AL and aPost-AL (1.22±2.40 mm) was significantly larger than between aUS-AL and aPost-AL (0.24±0.24 mm) and between fOB-AL and aPost-AL (0.35±0.49 mm) (P = 0.006, P = 0.016, respectively). CONCLUSION: The current findings suggest that aOB-AL is more accurate than aUS-AL or fOB-AL in cases of RRD without macular detachment, while aUS-AL or fOB-AL is more accurate than aOB-AL in cases with macular detachment.

Heat Exposure Following the Rainy Season Is Associated With an Increased Risk of Cardiovascular Emergency Among the Elderly in Japan.

Background Despite the impact of heat exposure caused by global warming, few studies have investigated the hourly effects of heat exposure and the risk of cardiovascular disease (CVD) in the elderly. We examined the associations between short-term heat exposure and the risk of CVD in the elderly in Japan and evaluated possible effect-measure modifications by rainy seasons that occur in East Asia. Methods and Results We conducted a time-stratified case-crossover study. The study included 6527 residents in Okayama City, Japan, aged ≥65 years who were transported to emergency hospitals between 2012 and 2019 for the onset of CVD during and a few months after the rainy seasons. We examined the linear associations between temperature and CVD-related emergency calls for each year and for hourly preceding intervals before the emergency call during the most relevant months. Heat exposure during 1 month after the end of the rainy season was associated with CVD risk; the odds ratio (OR) for a 1° C increase in temperature was 1.34 (95% CI, 1.29-1.40). When we further explored the nonlinear association by using the natural cubic spline model, we found a J-shaped relationship. Exposures 0 to 6 hours before the case event (preceding intervals 0-6 hours) were associated with CVD risk, particularly for the preceding interval 0 to 1 hour (OR, 1.33 [95% CI, 1.28-1.39]). For longer periods, the highest risk was at preceding intervals 0 to 23 hours (OR, 1.40 [95% CI, 1.34-1.46]). Conclusions Elderly individuals may be more susceptible to CVD after heat exposure during the month after the rainy season. As shown by finer temporal resolution analyses, short-term exposure to increasing temperature can trigger CVD onset.

IMPACT OF MACULAR INTRARETINAL HEMORRHAGE AND MACULAR HOLE ON THE VISUAL PROGNOSIS OF SUBMACULAR HEMORRHAGE DUE TO RETINAL ARTERIAL MACROANEURYSM RUPTURE.

PURPOSE: To compare the effects of macular intraretinal hemorrhage (IRH) and macular hole (MH) on best-corrected visual acuity (BCVA) after displacement of submacular hemorrhage (SMH) due to retinal arterial macroaneurysm (RAM) rupture. METHODS: This multicenter retrospective study included 48 eyes with SMH due to RAM rupture. Cases underwent vitrectomy to displace SMH and were followed up for 6 months. We classified cases according to the presence of IRH and MH and compared the postoperative BCVA among the groups. RESULTS: We classified the eyes into IRH(+)MH(+) group (10 eyes), IRH(+)MH(-) group (23 eyes), and IRH(-)MH(-) group (15 eyes). The postoperative BCVA was significantly worse in the IRH(+)MH(+) and IRH(+)MH(-) groups than in the IRH(-)MH(-) group (0.91 ± 0.41 in logarithm of the minimal angle of resolution units, Snellen equivalent 20/163, 0.87 ± 0.45, 20/148, and 0.18 ± 0.21, 20/30, respectively; P < 0.001). The postoperative central retinal thickness was significantly lower in the IRH(+) group (IRH(+)MH(+) and IRH(+)MH(-) groups combined) than in the IRH(-) group (IRH(-)MH(-) group) (121.4 ± 70.1 µ m and 174.3 ± 32.9 µ m, respectively, P = 0.008). The postoperative external limiting membrane and ellipsoid zone continuities were significantly discontinuous in the IRH(+) group ( P < 0.001, P = 0.001, respectively). The multiple linear regression analysis showed that both IRH(+)MH(+) and IRH(+)MH(-) were associated with the postoperative BCVA (regression coefficient, 0.799 and 0.711, respectively; P < 0.001 for both). CONCLUSION: Both IRH and MH were poor prognostic indicators in cases with SMH due to RAM rupture.

Diarrhea and related personal characteristics among Japanese university students studying abroad in intermediate- and low-risk countries.

Despite an increasing number of students studying abroad worldwide, evidence about health risks while they are abroad is limited. Diarrhea is considered the most common travelers' illness, which would also apply to students studying abroad. We examined diarrhea and related personal characteristics among Japanese students studying abroad. Japanese university students who participated in short-term study abroad programs between summer 2016 and spring 2018 were targeted (n = 825, 6-38 travel days). Based on a 2-week-risk of diarrhea (passing three or more loose or liquid stools per day) among travelers by country, the destination was separated into intermediate- and low-risk countries. After this stratification, the associations between personal characteristics and diarrhea during the first two weeks of their stay were evaluated using logistic regression models. Among participants in intermediate-risk countries, teenagers, males and those with overseas travel experience were associated with an elevated risk of diarrhea; the odds ratios (95% confidence intervals) were 2.42 (1.08-5.43) for teenagers (vs. twenties), 1.93 (1.08-3.45) for males (vs. females) and 2.37 (1.29-4.33) for those with overseas experience (vs. none). Even restricting an outcome to diarrhea during the first week did not change the results substantially. The same tendency was not observed for those in the low-risk countries. Teenage students, males and those with overseas travel experience should be cautious about diarrhea while studying abroad, specifically in intermediate-risk countries.

Exchangeability of Measures of Association Before and After Exposure Status Is Flipped: Its Relationship With Confounding in the Counterfactual Model.

BACKGROUND: The counterfactual definition of confounding is often explained in the context of exchangeability between the exposed and unexposed groups. One recent approach is to examine whether the measures of association (eg, associational risk difference) are exchangeable when exposure status is flipped in the population of interest. We discuss the meaning and utility of this approach, showing their relationships with the concept of confounding in the counterfactual framework. METHODS: Three hypothetical cohort studies are used, in which the target population is the total population. After providing an overview of the notions of confounding in distribution and in measure, we discuss the approach from the perspective of exchangeability of measures of association (eg, factual associational risk difference vs counterfactual associational risk difference). RESULTS: In general, if the measures of association are non-exchangeable when exposure status is flipped, confounding in distribution is always present, although confounding in measure may or may not be present. Even if the measures of association are exchangeable when exposure status is flipped, there could be confounding both in distribution and in measure. When we use risk difference or risk ratio as a measure of interest and the exposure prevalence in the population is 0.5, testing the exchangeability of measures of association is equivalent to testing the absence of confounding in the corresponding measures. CONCLUSION: The approach based on exchangeability of measures of association essentially does not provide a definition of confounding in the counterfactual framework. Subtly differing notions of confounding should be distinguished carefully.

Do Complementary and Alternative Medicine Users Also Use Conventional Medicine? A Repeated Cross-Sectional Study in Japan from 1995 to 2013.

Introduction: It is recommended that users of complementary and alternative medicine (CAM) also seek conventional medical care to prevent the loss of access to appropriate medical care. However, the status of such use is unknown. The aim of this study was to examine the time trends in the proportion of CAM users who also receive conventional medical care for the same symptoms. Methods: This is a repeated cross-sectional study. Of data for 753,978 respondents to the Comprehensive Survey of Living Conditions, which was conducted seven times between 1995 and 2013, data from 17,707 individuals who used acupuncture, moxibustion, anma-massage-shiatsu, or judo therapy were analyzed. Cross-classified multilevel logistic regression models with individuals as level 1 and survey year and cohort as level 2 were used to calculate odds ratios (ORs) and 95% credible intervals (CIs) for combined use of CAM and conventional medical care. Age was entered as an individual-level variable. The period effect after 2003 was entered as a survey year-level variable because the number of eligible persons providing CAM treatments has increased since 2003. Results: Among the 17,707 CAM users, 11,567 (65.3%) were women. When age was entered as an explanatory variable, the results showed that both older men and women tended to receive conventional medical care (women, OR: 1.04, 95% CI: 1.03-1.04; men, OR: 1.03, 95% CI: 1.02-1.04). Additional examination of the possible period effect after 2003 showed a positive (although nonsignificant) association (women, OR: 1.36, 95% CI: 0.89-1.99; men, OR: 1.37, 95% CI: 0.94-1.91). Conclusions: As patient age increased, patients combined CAM use with conventional medicine. The findings also suggested that the combined use of CAM and conventional medicine has increased since 2003.

Breastfeeding at 6 months of age had a positive impact on overweight and obesity in Japanese adolescents at 15 years of age.

AIM: A number of studies have indicated the potential benefits that breastfeeding has on reducing childhood obesity, but few studies have evaluated the effect on adolescent obesity. We examined the association between breastfeeding and overweight or obesity at 15 years of age using data from a large nationwide longitudinal study launched by the Japanese Government in 2001. METHODS: We analysed data for 26 164 participants with known infant feeding practices at 6 months of age, namely the duration of breastfeeding or formula feeding. Overweight or obesity at 15 years of age were calculated based on the subject's self-reported height and weight. Multinomial logistic regression analysis adjusted the data for child factors, namely sex, siblings, birth weight and physical activity clubs and the maternal factors of age, educational attainment and smoking status. RESULTS: Formula feeding was associated with an increased risk of overweight or obesity at 15 years of age. The adjusted odds ratios (95% confidence intervals) were 0.99 (0.89-1.09) for partial breastfeeding and 1.23 (1.02-1.48) for formula feeding, when exclusive breastfeeding was the reference category. CONCLUSION: Breastfeeding during infancy had potential benefits for overweight or obesity among 15-year-old adolescents. Our results provide further evidence of the importance of breastfeeding.

Tumor size before image-guided brachytherapy is an important factor of local control after radiotherapy for cervical squamous cell carcinoma: analysis in cases using central shielding.

We analyzed the local control (LC) of cervical squamous cell carcinoma treated by computed tomography (CT)-based image-guided brachytherapy (IGBT) using central shielding (CS). We also examined the value of tumor diameter before brachytherapy (BT) as a factor of LC. In total, 97 patients were analyzed between April 2016 and March 2020. Whole-pelvic (WP) radiotherapy (RT) with CS was performed, and the total pelvic sidewall dose was 50 or 50.4 Gy; IGBT was delivered in 3-4 fractions. The total dose was calculated as the biologically equivalent dose in 2 Gy fractions, and distribution was modified manually by graphical optimization. The median follow-up period was 31.8 months (6.3-63.2 months). The 1- and 2-year LC rates were 89% and 87%, respectively. The hazard ratio was 10.11 (95% confidence interval: 1.48-68.99) for local recurrence in those with a horizontal tumor diameter ≥ 4 cm compared to those with < 4 cm before BT. In CT-based IGBT for squamous cell carcinoma, favorable LC can be obtained in patients with a tumor diameter < 4 cm before BT. However, if the tumor diameter is ≥ 4 cm, different treatment strategies such as employing interstitial-BT for dose escalation may be necessary.

Incidence and clinical characteristics of spinal arteriovenous shunts: hospital-based surveillance in Okayama, Japan.

OBJECTIVE: There have been no accurate surveillance data regarding the incidence rate of spinal arteriovenous shunts (SAVSs). Here, the authors investigate the epidemiology and clinical characteristics of SAVSs. METHODS: The authors conducted multicenter hospital-based surveillance as an inventory survey at 8 core hospitals in Okayama Prefecture between April 1, 2009, and March 31, 2019. Consecutive patients who lived in Okayama and were diagnosed with SAVSs on angiographic studies were enrolled. The clinical characteristics and the incidence rates of each form of SAVS and the differences between SAVSs at different spinal levels were analyzed. RESULTS: The authors identified a total of 45 patients with SAVSs, including 2 cases of spinal arteriovenous malformation, 5 cases of perimedullary arteriovenous fistula (AVF), 31 cases of spinal dural AVF (SDAVF), and 7 cases of spinal epidural AVF (SEAVF). The crude incidence rate was 0.234 per 100,000 person-years for all SAVSs including those at the craniocervical junction (CCJ) level. The incidence rate of SDAVF and SEAVF combined increased with advancing age in men only. In a comparative analysis between upper and lower spinal SDAVF/SEAVF, hemorrhage occurred in 7/14 cases (50%) at the CCJ/cervical level and in 0/24 cases (0%) at the thoracolumbar level (p = 0.0003). Venous congestion appeared in 1/14 cases (7%) at the CCJ/cervical level and in 23/24 cases (96%) at the thoracolumbar level (p < 0.0001). CONCLUSIONS: The authors reported detailed incidence rates of SAVSs in Japan. There were some differences in clinical characteristics of SAVSs in the upper spinal levels and those in the lower spinal levels.