Body Mass Index and Risks of Incident Ischemic Stroke Subtypes: The Japan Public Health Center-Based Prospective (JPHC) Study

Nonrestorative Sleep and Type 2 Diabetes Incidence: The Aichi Workers' Cohort Study

BACKGROUND

The term "nonrestorative sleep (NRS)" refers to an unrefreshed feeling at wake-up and is a domain of poor sleep quality. Previous research has demonstrated that NRS is linked to a number of diseases and adverse health outcomes, but less is known regarding the link between NRS and diabetes, particularly in Japanese.

METHODS

We studied 3,665 middle-aged male participants of the Aichi Workers' Cohort Study who were followed-up from 2002 through 2019. Cox proportional hazards models estimated hazard ratios (HRs) and 95% confidence intervals (CIs) of incident type 2 diabetes mellitus (T2DM) in relation to NRS adjusted for potential confounding variables.

RESULTS

During a median follow-up of 14.6 years, 421 type 2 diabetes cases were identified. Participants with NRS had a higher crude incidence rate of T2DM (11.2/1,000 person-years), compared to participants without NRS (9.3/1,000 person-years). In the fully adjusted model, individuals who reported having NRS had a significantly higher risk of developing T2DM (HR1.36; 95% CI, 1.10-1.67). The association was observed only in participants under 50 years old (HR 1.82; 95% CI, 1.36-2.43), not in the older (50 years or older) participants (P for interaction = 0.025). In contrast, stratified analyses by the presence of shift work, obesity, or sleep duration showed similar associations in all the strata.

CONCLUSION

NRS was associated with higher risk of T2DM in middle-aged Japanese male workers independent of a variety of lifestyle factors and other sleep problems.

Risk and Population Attributable Fraction of Stroke Subtypes in Japan

BACKGROUND

Associations of major risk factors for stroke with total and each type of stroke, as well as subtypes of ischemic stroke, and their population attributable fractions had not been examined comprehensively.

METHODS

Participants of the Japan Public Health Center-based prospective (JPHC) Study Cohort II without histories of cardiovascular disease and cancer (n = 14,797) were followed from 1993 through 2012. Associations of current smoking, hypertension, diabetes, overweight (body mass index ≥25 kg/m2), non-high-density lipoprotein cholesterol (non-HDLC) categories, low HDLC (<40 mg/dL), urine protein, and history of arrhythmia were examined in a mutually-adjusted Cox regression model that included age and sex. Population attributable fractions (PAFs) were estimated using the hazard ratios and the prevalence of risk factors among cases.

RESULTS

Subjects with hypertension were 1.63 to 1.84 times more likely to develop any type of stroke. Diabetes, low HDLC, current smoking, overweight, urine protein, and arrhythmia were associated with risk of overall and ischemic stroke. Hypertension and urine protein were associated with risk of intracerebral hemorrhage, while current smoking, hypertension, and low non-HDLC were associated with subarachnoid hemorrhage. Hypertension alone accounted for more than a quarter of stroke incidence, followed by current smoking and diabetes. High non-HDLC, current smoking, low HDLC, and overweight contributed mostly to large-artery occlusive stroke. Arrhythmia explained 13.2% of embolic stroke. Combined PAFs of all the modifiable risk factors for total, ischemic, and large-artery occlusive strokes were 36.7%, 44.5%, and 61.5%, respectively.

CONCLUSION

Although there are differences according to subtypes, hypertension could be regarded as the most crucial target for preventing strokes in Japan.

Associations of overweight and obesity with the risk of cardiovascular disease according to metabolic risk factors among middle-aged Japanese workers: The Aichi Workers' cohort study

BACKGROUND

The association between obesity and cardiovascular disease (CVD) remains unclear, particularly for those with established CVD risk factors. We analyzed follow-up data from the Aichi Workers' Cohort Study. We studied the association between the degree of obesity and risk of CVD and its subtypes specifically among individuals with hypertension, hyper-low-density lipoprotein (LDL)-cholesterolemia, or diabetes.

METHODS

Pooled data of 8972 adults (7076 men and 1896 women) who were recruited between 2002 and 2008 were used in the current analysis. We used multivariable Cox proportional hazard model to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations between the degree of obesity assessed with body mass index (BMI) and the risk of CVD and its subtypes, i.e., coronary heart disease (CHD) and stroke.

RESULTS

During a median of 12 years, there were 197 CVDs (80 CHDs and 117 strokes). BMI ≥ 27.5 compared to 21.0-22.9 kg/m2 was positively and significantly associated with the risks of CVD, CHD, and total stroke. Hypertension, hyper-LDL-cholesterolemia, and diabetes mediated 15.9%, 5.8%, and 8.7% of obesity-CVD associations, respectively, and 28.3% by their combination. In the stratified analyses by the presence of risk factors, BMI ≥ 25.0 (overweight/obesity) compared to BMI < 25 kg/m2 was associated with a higher risk of CVD in those with and without hypertension, but only with hyper-LDL-cholesterolemia, and without diabetes.

CONCLUSIONS

Overweight/obesity was associated with the risk of CVD and its subtypes. About 30% of the risk was explained by hypertension, hyper-LDL-cholesterolemia, and diabetes, of which hypertension accounted for approximately the half of the explained risk. However, overweight/obesity increased the risk of CVD even in those without hypertension. These findings highlight the importance of controlling and preventing overweight/obesity regardless of chronic disease status.

The effect of age on the relationship between body mass index and risks of incident stroke subtypes: The JPHC study

OBJECTIVE

The associations between body mass index (BMI) and stroke subtypes, particularly intracerebral hemorrhage, have not been consistent. Such inconsistencies may be due to differences in the age at which BMI was obtained. We examined the possible age modifications in the association between BMI and stroke risk.

MATERIALS AND METHODS

We followed 88,754 participants, aged 40-69 years at baseline (1990-1994), of the Japan Public Health Center-based prospective (JPHC) study for stroke incidence. BMI was obtained using self-reported body weight and height, which were categorized using the following cut-off points: 18.5, 21, 23, 25, 27.5, and 30 kg/m2. Time-dependent Cox proportional hazards models that updated BMI and covariates using 5- and 10-year questionnaire responses were used to estimate hazard ratios and 95 % confidence intervals. The analyses were stratified by age group (40-59 and ≥60 years) and the age of the individuals was updated.

RESULTS

During the median follow-up period of 19 years, we documented 4,690 strokes, including 2,781 ischemic strokes and 1,358 intracerebral hemorrhages. After adjusting for sex, age, smoking, alcohol consumption, leisure-time physical activity, history of hypertension, dyslipidemia, and diabetes mellitus, we observed a positive linear association between BMI and ischemic stroke (linear trend, p < 0.001) in both age groups (interaction p>0.05). In contrast, a curvilinear association between BMI and intracerebral hemorrhage was observed in both the middle (curvilinear trend, p=0.017) and the older group (curvilinear trend, p=0.098) (interaction p>0.05).

CONCLUSION

BMI and stroke associations did not vary significantly with age, although the association may differ according to subtype.

Body Mass Index Asian populations category and stroke and heart disease in the adult population: a longitudinal study of the Indonesia Family Life Survey (IFLS) 2007 and 2014

BACKGROUND

A substantially elevated Body Mass Index (BMI) is one of the largest global modifiable risk factors for stroke and heart diseases. Most studies classify BMI according to the WHO BMI cut-off point in stroke and heart disease studies. However, there is a limited understanding of the association between the BMI cut-off point in the Asian population category and stroke and heart disease. This study aimed to investigate the incidence rate ratio of stroke and heart disease by BMI categories for the Asian population.

METHODS

A 7-year prospective longitudinal study (2007-2014) was conducted on 6,688 adult Indonesian individuals (≥ 35 years) residing across 13 different provinces in Indonesia during the survey periods. Data on BMI were collected in 2007. Information on stroke and heart disease was obtained in both 2007 and in 2014. A multivariate-adjusted Poisson regression model was used to estimate the incidence rate ratio (IRR) and 95% confidence intervals (CIs) of either stroke or heart disease or both stroke and heart disease by BMI.

RESULTS

Among the 6,688 eligible participants, 334 (5%) were judged as stroke and heart disease in 2014. The IRR (95% CI) of stroke and heart disease for participants with obesity was 2.57 (1.64-4.04) compared with those within normal weight. This incidence rate ratio was more pronounced among middle-aged adults (< 55 years) rather than the older adults (≥55 years).The IRR of stroke and heart disease among obese middle-aged adults was 4.18 (95% CI 2.10-8.31).

CONCLUSIONS

An association was observed between obesity and the risk of stroke and heart disease, especially in middle-aged adults. These findings suggest that lowering BMI through the adoption of healthy dietary habits and increasing physical activity, particularly among middle-aged adults with high education, occupational employment, and residence in either urban or rural areas, may be beneficial for preventing stroke and heart disease.

Body Mass Index and Late Adverse Outcomes after a Carotid Endarterectomy

A cohort study was conducted to examine the association of an increased body mass index (BMI) with late adverse outcomes after a carotid endarterectomy (CEA). It comprised 1597 CEAs, performed in 1533 patients at the Vascular Surgery Clinic in Belgrade, from 1 January 2012 to 31 December 2017. The follow-up lasted four years after CEA. Data for late myocardial infarction and stroke were available for 1223 CEAs, data for death for 1305 CEAs, and data for restenosis for 1162 CEAs. Logistic and Cox regressions were used in the analysis. The CEAs in patients who were overweight and obese were separately compared with the CEAs in patients with a normal weight. Out of 1223 CEAs, 413 (33.8%) were performed in patients with a normal weight, 583 (47.7%) in patients who were overweight, and 220 (18.0%) in patients who were obese. According to the logistic regression analysis, the compared groups did not significantly differ in the frequency of myocardial infarction, stroke, and death, as late major adverse outcomes (MAOs), or in the frequency of restenosis. According to the Cox and logistic regression analyses, BMI was neither a predictor for late MAOs, analyzed separately or all together, nor for restenosis. In conclusion, being overweight and being obese were not related to the occurrence of late adverse outcomes after a carotid endarterectomy.

Body mass index and early outcomes after carotid endarterectomy

As the existing data on the correlation of adiposity with adverse outcomes of carotid endarterectomy (CEA) are inconsistent, the aim of the present study is to examine the correlation of an increased body mass index with 30-day complications after carotid endarterectomy. The cohort study comprises 1586 CEAs, performed at the Clinic for Vascular Surgery in Belgrade, from 2012-2017. Out of them, 550 CEAs were performed in patients with normal body mass index (18.5-24.9), 750 in overweight (25.0-29.9), and 286 in obese (≥30) patients. The association of overweight and obesity with early outcomes of carotid endarterectomy was assessed using univariate and multivariate logistic regression analysis. Overweight patients, in whom CEAs were performed, were significantly more frequently males, compared to normal weight patients-Odds Ratio (OR) 1.51 (95% confidence interval- 1.19-1.89). Moreover, overweight patients significantly more frequently had non-insulin-dependent diabetes mellitus-OR 1.44 (1.09-1.90), and more frequently used ACEI in hospital discharge therapy-OR 1.41 (1.07-1.84) than normal weight patients. Additionally, the CEAs in them were less frequently followed by bleedings-OR 0.37 (0.16-0.83). Compared to normal weight patients, obese patients were significantly younger-OR 0.98 (0.96-0.99), and with insulin-dependent and non-insulin-dependent diabetes mellitus-OR 1.83 (1.09-3.06) and OR 2.13 (1.50-3.01) respectively. They also more frequently had increased triglyceride levels-OR 1.36 (1.01-1.83), and more frequently used oral anticoagulants in therapy before the surgery-OR 2.16 (1.11-4.19). According to the results obtained, overweight and obesity were not associated with an increased death rate, transient ischemic attack (TIA), stroke, myocardial infarction, or with minor complications, and the need for reoperation after carotid endarterectomy. The only exception was bleeding, which was significantly less frequent after CEA in overweight compared to normal weight patients.

Body mass index has a non-linear association with three-month outcomes in men with acute ischemic stroke: An analysis based on data from a prospective cohort study

Objective

Despite reports of a connection between body mass index (BMI) and stroke outcome, the findings remain debatable. In this investigation, we sought to determine whether BMI was associated with the probability of 3-month unfavorable outcomes in patients with acute ischemic stroke (AIS).

Methods

This is a second analysis based on a cohort study. 1,897 people with AIS who were treated at a hospital in South Korea from January 2010 to December 2016 were included in the study. The linear relationship between BMI and unfavorable outcomes for AIS patients was evaluated using a binary logistic regression model. The generalized additive model (GAM) and smoothed curve fitting (penalized spline approach) were employed to see if there was a non-linear association between BMI and unfavorable outcomes in patients with AIS.

Results

The binary logistic regression model did not detect any statistically significant correlation between BMI and unfavorable outcomes in AIS patients after controlling for variables. The association between them, however, was non-linear, with the BMI inflection point occurring at 23.07 kg/m2. Each 1 kg/m2 rise in BMI on the left side of the inflection point was linked to a 12% lower risk of unfavorable outcomes (OR= 0.88, 95% CI: 0.82 to 0.96, p = 0.003). We stratified the AIS patients by gender to further explore their relationship. The results showed a specific non-linear relationship and saturation effect of BMI (kg/m2) with 3-month unfavorable outcomes in male patients but not in female patients. The inflection point for BMI was 23.35 kg/m2. When BMI was below 23.35 kg/m2 in men with AIS, BMI was inversely associated with unfavorable outcomes (OR=0.89,95% CI:0.80-0.98).

Conclusion

A particular non-linear connection and saturation effect between BMI (kg/m2) and 3-month unfavorable outcomes were present in male patients with AIS but not in females. 23.35 kg/m2 was the BMI's inflection point. The probability of unfavorable outcomes was substantially and inversely associated with BMI in men with AIS when it was less than 23.35 kg/m2. Men with AIS should have a BMI of no less than 23.35 kg/m2 to reduce the probability of unfavorable outcomes following AIS.

Women's reproductive traits and ischemic stroke: a two-sample Mendelian randomization study

OBJECTIVE

We conducted a Mendelian randomization (MR) study to disentangle causal associations between women's reproductive behaviors and ischemic stroke (IS) and investigate the roles of two modifiable risk factors (body mass index (BMI) and educational attainment (EA)) in these associations.

METHODS

Using summary-level data from large-scale genome-wide association studies, we performed univariable MR to examine whether there is genetic evidence that women's reproductive traits are causally associated with IS and its subtypes. Multivariable MR and MR mediation analysis were used to investigate whether BMI and EA are common mechanisms or mediators for these associations. A set of sensitivity analyses were conducted to test valid MR assumptions.

RESULTS

We observed consistent and statistically significant associations across female and sex-combined analyses for earlier age at first birth (AFB) and age at first sexual intercourse (AFS) with a higher risk of IS and large-artery atherosclerotic stroke (LAS) risk in the primary analysis. The odds ratios of IS per 1 SD increase in genetically predicted early AFB and AFS were 0.93 (95% CI, 0.86-0.99; p = 0.046) and 0.83 (95% CI, 0.70-0.97, p = 0.020), respectively. Further analyses indicated that BMI played a shared role in AFS and IS/LAS while EA played a shared role in AFS/AFB and IS/LAS as well as a mediator in the path from AFS to IS/LAS.

INTERPRETATION

These findings may inform prevention strategies and interventions directed toward relative women's reproductive behaviors and IS. Future studies are warranted to explore other factors related to EA which are responsible for these causalities.

The relationship between body mass index and stroke: a systemic review and meta-analysis

BACKGROUND

Stroke is an acute cerebrovascular event closely related to brain tissue damage, and is one of the major causes of death and disability in worldwide. Various studies have reported the effects of body mass index (BMI) on the risk of stroke, but the results remain varied and these results have not been synthesized. Therefore, a meta-analysis was performed to evaluate the relationship between BMI and the risk of stroke.

OBJECTIVES

This systematic review was conducted to explore the relationship between BMI and the risk of stroke.

METHODS

PubMed, EMBASE, Web of Science and Cochrane Library, China Knowledge Resource Integrated Database (CNKI), WanFang Database, Chinese Biomedical Database (CBM), and CQVIP were comprehensively searched for studies exploring the relationship between BMI and stroke from inception to December 1, 2021.

RESULTS

This review included 24 studies involving 5,798,826 subjects. The results of meta-analysis showed that the pooled RR of stroke risk was 0.93 (95% confidence interval [CI] 0.82-1.06, I² = 88.8%, P = 0.29) for the underweight group. Higher BMI (overweight or obese group) was associated with an increased overall risk of stroke, with pooled RR values of 1.25 (95% CI 1.16-1.34, I² = 84.8%, P = 0.00) and 1.47 (95% CI: 1.02-2.11, I² = 99.4%, P = 0.04).

CONCLUSION

The risk of stroke was positively correlated with BMI, and the association was stronger in male and ischemic stroke. Lowering BMI can be used as a way to prevent stroke, and for people who are overweight or obese, lowering body weight can reduce the risk of stroke.

Influence of BMI on adenosine deaminase and stroke outcomes in mechanical thrombectomy subjects

Background

Emergent Large Vessel Occlusion (ELVO) strokes are ischemic vascular events for which novel biomarkers and therapies are needed. The purpose of this study is to investigate the role of Body Mass Index (BMI) on protein expression and signaling at the time of ELVO intervention. Additionally, we highlight the protein adenosine deaminase (ADA), which is a deaminating enzyme that degrades adenosine, which has been shown to be neuroprotective in ischemia. We investigate the relationship between ADA and BMI, stroke outcomes, and associated proteomic networks which might aid in personalizing prognosis and future treatment of ELVO stroke.

Methods

The Blood And Clot Thrombectomy And Collaboration (BACTRAC) study is a continually enrolling tissue bank (clinicaltrials.gov NCT03153683) and registry from stroke patients undergoing mechanical thrombectomy (MT). N ​= ​61 human carotid plasma samples were analyzed for inflammatory and cardiometabolic protein expression by Olink Proteomics. Statistical analyses used t-tests, linear, logistic, and robust regressions, to assess the relationship between BMI, proteomic expression, and stroke-related outcomes.

Results

The 61 subjects studied were broken into three categories: normal weight (BMI 18.5–24.9) which contained 19 subjects, overweight (BMI 25–30) which contained 25 subjects, and obese (BMI ≥30) which contained 17 subjects. Normal BMI group was a significantly older population (mean 76 years) when compared to overweight (mean 66 years) and obese (mean 61 years) with significance of p ​= ​0.041 and p ​= ​0.005, respectively. When compared to normal weight and overweight categories, the obese category had significantly higher levels of adenosine deaminase (ADA) expression (p ​= ​0.01 and p ​= ​0.039, respectively). Elevated levels of ADA were found to have a significant positive correlation with both infarct volume and edema volume (p ​= ​0.013 and p ​= ​0.041, respectively), and were associated with a more severe stroke (NIHSS on discharge) and greater stroke related disability (mRS on discharge) with significance of p ​= ​0.053 and p ​= ​0.032, respectively.

Conclusions

When examined according to BMI, subjects undergoing MT for ELVO demonstrate significant differences in the expression of certain plasma proteins, including ADA. Levels of ADA were found to be significantly higher in the obese population when compared to normal or overweight groups. Increased levels of ADA in the obese group were predictive of increased infarct volume, edema volume, and worse NIHSS scores and mRS at discharge. These data provide novel biomarker candidates as well as treatment targets while increasing the personalization of stroke prognosis and treatment.

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Adenosine deaminase is minimally reported on in the stroke literature.

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In our cohort of ischemic ELVO stroke patients treated with mechanical thrombectomy:

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Subjects with higher BMI had higher ADA expression.

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Higher ADA is predictive of larger infarct volume, edema volume, and increased mRS and NIHSS on discharge.

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ADA and related proteins may serve as novel and personalized prognostic biomarkers as well as potential therapeutic targets.

Combined consideration of body mass index and waist circumference identifies obesity patterns associated with risk of stroke in a Chinese prospective cohort study

Background

In China, few studies have examined the relationship between the combination of body mass index and waist circumference and the risk of stroke. Moreover, the relationship may also be different in different genders. Thus, we investigated the association between the combination of body mass index and waist circumference and the risk of stroke in Chinese.

Methods

This prospective cohort study included 36 632 participants aged 18 to 90 years. Participants were recruited from 60 surveillance sites (25 urban sites and 35 rural sites) across China in 2010 China Chronic Disease Risk Factor Surveillance, and followed up in 2016-2017. Incident cases of stroke were identified through questionnaires (including the basis of clinical diagnosis, imaging tests, time of diagnosis, diagnosis unit) and Cardiovascular Event Report System. Risk factors for stroke were collected at baseline using questionnaire, physical measurements and laboratory tests. Cox proportional hazards regression models were used to generate adjusted hazard ratios and 95%CI. All analyses were duplicated by gender stratification.

Results

During 6.42 ± 0.50 years of follow-up, 1 333 (597 males, 736 females) stroke events were observed among the 27 112 participants who did not have cardiovascular diseases at baseline. Compared with the general population who have normal weight or underweight with normal WC, those who have normal weight or underweight with abdominal obesity (adjusted hazard ratios 1.45, 95%CI 1.07-1.97 in males; 0.98, 95%CI 0.78-1.24 in females), overweight with abdominal obesity (1.41, 95%CI 1.14-1.75 in males; 1.33, 95%CI 1.10-1.61 in females), obesity with abdominal obesity (1.46, 95%CI 1.11-1.91 in males; 1.46, 95%CI 1.17-1.81 in females). Overweight with normal WC was found to be not statistically significant for both males and females (all P>0.05). Subgroup analysis found a multiplicative interaction between age and anthropometric group in females (P for interaction <0.05). Sensitivity analysis results did not change. In the subjects with CVD risk factors, we found a similar relationship as in the general population .

Conclusions

Combined assessment of body mass index and waist circumference identifies obesity patterns associated with stroke risk.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12756-2.

The Lifelong Health Support 10: a Japanese prescription for a long and healthy life

BACKGROUND

Although the age-adjusted incidence and mortality of cancer and cardiovascular disease (CVD) have been decreasing steadily in Japan, both diseases remain major contributors to morbidity and mortality along with the aging society. Herein, we aim to provide a prescription of 10 health tips for long and healthy life named the "Lifelong Health Support 10 (LHS10)."

METHOD

The LHS10 was developed by the preventive medicine specialists at the National Cerebral and Cardiovascular Center in Suita, where it has been used for health guidance to prevent CVD, cancer, and cognitive decline in addition to their major risk factors such as hypertension, diabetes, and obesity. It consisted of the lifestyle modification recommendations of the 2014 Japanese Society of Hypertension guidelines and the 2017 Japan Atherosclerosis Society Guidelines for preventing atherosclerotic CVD. Further, it came in line with other international lifestyle modification guidelines. In this narrative review, we summarized the results of several Japanese epidemiological studies investigating the association between the LHS10 items and the risk of cancer, CVD, and other chronic diseases including dementia, diabetes, and chronic kidney disease.

RESULTS

The LHS10 included avoiding smoking and secondhand smoke exposure, engaging in physical activity, refraining from excessive alcohol drinking, reducing fried foods and sugary soft drinks, cutting salt in food, consuming more vegetables, fruits, fish, soy foods, and fibers, and maintaining proper body weight. All items of the LHS10 were shown to reduce the risk of cancer, CVD, and other chronic diseases.

CONCLUSIONS

The LHS10 can be a helpful tool for health guidance.

Machine Learning-Based Model for Predicting Incidence and Severity of Acute Ischemic Stroke in Anterior Circulation Large Vessel Occlusion

Objectives: Patients with anterior circulation large vessel occlusion are at high risk of acute ischemic stroke, which could be disabling or fatal. In this study, we applied machine learning to develop and validate two prediction models for acute ischemic stroke (Model 1) and severity of neurological impairment (Model 2), both caused by anterior circulation large vessel occlusion (AC-LVO), based on medical history and neuroimaging data of patients on admission.

Methods: A total of 1,100 patients with AC- LVO from the Second Hospital of Hebei Medical University in North China were enrolled, of which 713 patients presented with acute ischemic stroke (AIS) related to AC- LVO and 387 presented with the non-acute ischemic cerebrovascular event. Among patients with the non-acute ischemic cerebrovascular events, 173 with prior stroke or TIA were excluded. Finally, 927 patients with AC-LVO were entered into the derivation cohort. In the external validation cohort, 150 patients with AC-LVO from the Hebei Province People's Hospital, including 99 patients with AIS related to AC- LVO and 51 asymptomatic AC-LVO patients, were retrospectively reviewed. We developed four machine learning models [logistic regression (LR), regularized LR (RLR), support vector machine (SVM), and random forest (RF)], whose performance was internally validated using 5-fold cross-validation. The performance of each machine learning model for the area under the receiver operating characteristic curve (ROC-AUC) was compared and the variables of each algorithm were ranked.

Results: In model 1, among the included patients with AC-LVO, 713 (76.9%) and 99 (66%) suffered an acute ischemic stroke in the derivation and external validation cohorts, respectively. The ROC-AUC of LR, RLR and SVM were significantly higher than that of the RF in the external validation cohorts [0.66 (95% CI 0.57–0.74) for LR, 0.66 (95% CI 0.57–0.74) for RLR, 0.55 (95% CI 0.45–0.64) for RF and 0.67 (95% CI 0.58–0.76) for SVM]. In model 2, 254 (53.9%) and 31 (37.8%) patients suffered disabling ischemic stroke in the derivation and external validation cohorts, respectively. There was no difference in AUC among the four machine learning algorithms in the external validation cohorts.

Conclusions: Machine learning methods with multiple clinical variables have the ability to predict acute ischemic stroke and the severity of neurological impairment in patients with AC-LVO.

Associations between cerebral magnetic resonance imaging infarct volume and acute ischemic stroke etiology

BACKGROUND

Identifying ischemic stroke etiology is necessary for proper treatment and secondary prevention. We sought to define associations between infarct volume and stroke subtypes.

MATERIALS AND METHODS

Inclusion criteria necessitated a Johns Hopkins Hospital inpatient admission (2017-2019) for ischemic stroke with confirmatory brain magnetic resonance imaging. Infarct volume was calculated using MRIcron© by a masked reviewer. Ischemic strokes were adjudicated using TOAST classification. Multivariable/multinomial logistic regression determined associations between infarct volume and stroke subtypes with interaction terms for infarct number and location. Stepwise adjustment accounted for potential confounders.

RESULTS

Patients (N = 150) were on average 61 years old, male (58%), and black (57%). Each 5mL increase in infarct volume was associated with cardioembolic (OR 1.07, 95%CI 1.01-1.14) and large-artery occlusions (OR 1.10, 95%CI 1.02-1.18), but lower odds of lacunar stroke (OR 0.18, 95%CI 0.06-0.55). There was no difference in risk of cardioembolic (base) and large-artery atherosclerotic strokes with increasing infarct volume (RRR 1.01, 95%CI 0.94-1.09), but risk of lacunar stroke was decreased (RRR 0.17, 95%CI 0.06-0.53). Infarct number (single vs multiple) modified the association between volume and subtype for large-artery occlusions (p-interaction 0.09).

CONCLUSIONS

In this study, larger volume infarcts were significantly associated with both cardioembolic and large-artery atherosclerotic strokes (no difference in the degree of association) and decreased odds of lacunar stroke. A single, large-volume stroke was associated with large-artery atherosclerosis, while multiple infarcts were associated with cardioembolism. Given the differential associations between volume, number of lesions, and stroke etiology, defining stroke subtypes in light of infarct volume might aid in clinical practice.

The association between serine hydroxymethyl transferase 1 gene hypermethylation and ischemic stroke

This study aimed to determine the correlation between serine hydroxymethyl transferase 1 (SHMT1) gene methylation and ischemic stroke. A total of 202 age- and sex-matched individuals were included. Quantitative methylation-specific polymerase chain reaction (qMSP-PCR) was used to analyze the DNA methylation level. The plasma homocysteine (Hcy) concentration was much higher in ischemic cases than in controls (p = 0.009), while the high-density lipoprotein (HDL) levels in stroke cases were considerably lower than in controls (p = 0.005). A significantly higher level of SHMT1 methylation was observed in the ischemic strokes (58.82 ± 17.83%) compared to that in the controls (42.59 ± 20.76%, p < 0.001). The SHMT1 methylation level was strongly correlated with HDL concentration in the healthy controls (r = 0.517, p < 0.001), while the high plasma level of Hcy showed strong association with SHMT1 methylation in ischemic strokes (r = 0.346, p < 0.001). Receiver operating characteristic (ROC) analysis of curve indicated that SHMT1 methylation has been an acceptable indicator for ischemic stroke in female patients [all sexes, area under the curve (AUC) = 0.71, p < 0.001; male patients AUC = 0.62, p = 0.032; and female patients AUC = 0.79, p < 0.001] and in all ages (AUC = 0.71, p < 0.001). In our samples, DNA methylation levels of the STHMI gene were significantly correlated with ischemic stroke in Han Chinese. STHMI hypermethylation was significantly associated with the high Hcy concentration in ischemic stroke and had value as a potential indicator for female ischemic stroke.

Modifiable Risk Factors for Cardiovascular Disease in Korea and Japan

Cardiovascular disease (CVD) is the leading cause of death and a major contributor to disability worldwide. Since the majority of cardiovascular events are preventable, identification of modifiable CVD risk factors and implementation of primordial prevention strategies should be a public health priority. In this aspect, the American Heart Association declared a strategic goal to reduce total CVD mortality in the US by 20% within 10 years via eliminating 7 major CVD risk factors (hypertension, diabetes, dyslipidemia, cigarette smoking, physical inactivity, obesity, and poor-quality diet) in 2010, and their strategy has been achieving. However, the applicability of similar metrics to prevent CVD among East Asians requires an in-depth investigation of the modifiable CVD risk factors based on national and regional evidence-based findings. Herein, this review article aims to discuss several modifiable risk factors for CVDs, using epidemiological evidence from cohort studies and nationally representative data of 2 East Asian countries: Korea and Japan.

Relation Between Body Mass Index and Dry Eye Disease: The Japan Public Health Center-Based Prospective Study for the Next Generation

OBJECTIVE

To investigate the relation between body mass index (BMI) and dry eye disease (DED).

METHODS

We conducted a cross-sectional questionnaire-based survey in 85,264 Japanese men and women aged 40 to 74 years who participated in the Japan Public Health Center-based Prospective Study for the Next Generation (JPHC-NEXT Study). Dry eye disease was defined as the presence of severe symptoms or clinical diagnosis. A multivariable logistic regression model was used to estimate the odds ratios (ORs) of DED associated with BMI and their two-sided 95% confidence intervals (CIs). We adjusted for age, cohort area, visual display terminal time, smoking status, alcohol intake, education status, income status, as well as history of hormone replacement therapy for women.

RESULTS

Prevalence of DED was 23.4% (n = 19,985; 6,289 men, 13,696 women). Higher BMI was correlated with a lower prevalence of DED in a dose-response fashion, with an adjusted OR of DED (95% CI) per 1 kg/m2 increment of BMI of 0.98 (95% CI: 0.97-0.99) for men and 0.97 (95% CI: 0.97-0.98) for women.

CONCLUSIONS

This large population-based study showed an inverse relationship between BMI and prevalence of DED in a Japanese population. Underestimation of DED is warned, especially for participants with high BMI.

Estimation of 10-Year Risk of Death from Coronary Heart Disease, Stroke, and Cardiovascular Disease in a Pooled Analysis of Japanese Cohorts: EPOCH-JAPAN

AIMS

We aimed to develop and validate risk prediction models to estimate the absolute 10-year risk of death from coronary heart disease (CHD), stroke, and cardiovascular disease (CVD).

METHODS

We evaluated a total of 44,869 individuals aged 40-79 years from eight Japanese prospective cohorts to derive coefficients of risk equations using cohort-stratified Cox proportional hazard regression models. Discrimination (C-index) of the equation was examined in each cohort and summarised using random-effect meta-analyses. Calibration of the equation was assessed using Hosmer-Lemeshow chi-squared statistic.

RESULTS

Within a median follow-up of 12.7 years, we observed 765 deaths due to CVD (276 CHDs and 489 strokes). After backward selection, age, sex, current smoking, systolic blood pressure (SBP), proteinuria, prevalent diabetes mellitus, the ratio of total cholesterol to high-density lipoprotein cholesterol (TC/HDLC), interaction terms of age by SBP, and age by current smoking were retained as predictors for CHD. Sex was excluded in the stroke equation. We did not consider TC/HDLC as a risk factor for the stroke and CVD equations. The pooled C-indices for CHD, stroke, and CVD were 0.83, 0.80, and 0.81, respectively, and the corresponding p-values of the Hosmer-Lemeshow tests were 0.18, 0.003, and 0.25, respectively.

CONCLUSIONS

Risk equations in the present study can adequately estimate the absolute 10-year risk of death from CHD, stroke, and CVD. Future work will evaluate the system as an education and risk communication tool for primary prevention of CHD and stroke.

The effect of exposure to long working hours on stroke: A systematic review and meta-analysis from the WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury

BACKGROUND

The World Health Organization (WHO) and the International Labour Organization (ILO) are developing joint estimates of the work-related burden of disease and injury (WHO/ILO Joint Estimates), with contributions from a large network of individual experts. Evidence from mechanistic data and prior studies suggests that exposure to long working hours may cause stroke. In this paper, we present a systematic review and meta-analysis of parameters for estimating the number of deaths and disability-adjusted life years from stroke that are attributable to exposure to long working hours, for the development of the WHO/ILO Joint Estimates.

OBJECTIVES

We aimed to systematically review and meta-analyse estimates of the effect of exposure to long working hours (three categories: 41-48, 49-54 and ≥55 h/week), compared with exposure to standard working hours (35-40 h/week), on stroke (three outcomes: prevalence, incidence, and mortality).

DATA SOURCES

A protocol was developed and published, applying the Navigation Guide to systematic reviews as an organizing framework where feasible. We searched electronic databases for potentially relevant records from published and unpublished studies, including Ovid MEDLINE, PubMed, EMBASE, Scopus, Web of Science, CISDOC, PsycINFO, and WHO ICTRP. We also searched grey literature databases, Internet search engines, and organizational websites; hand-searched reference lists of previous systematic reviews; and consulted additional experts.

STUDY ELIGIBILITY AND CRITERIA

We included working-age (≥15 years) individuals in the formal and informal economy in any WHO and/or ILO Member State but excluded children (aged < 15 years) and unpaid domestic workers. We included randomized controlled trials, cohort studies, case-control studies and other non-randomized intervention studies with an estimate of the effect of exposure to long working hours (41-48, 49-54 and ≥55 h/week), compared with exposure to standard working hours (35-40 h/week), on stroke (prevalence, incidence or mortality).

STUDY APPRAISAL AND SYNTHESIS METHODS

At least two review authors independently screened titles and abstracts against the eligibility criteria at a first review stage and full texts of potentially eligible records at a second stage, followed by extraction of data from qualifying studies. Missing data were requested from principal study authors. We combined relative risks using random-effects meta-analysis. Two or more review authors assessed the risk of bias, quality of evidence and strength of evidence, using the Navigation Guide and GRADE tools and approaches adapted to this project.

RESULTS

Twenty-two studies (20 cohort studies, 2 case-control studies) met the inclusion criteria, comprising a total of 839,680 participants (364,616 females) in eight countries from three WHO regions (Americas, Europe, and Western Pacific). The exposure was measured using self-reports in all studies, and the outcome was assessed with administrative health records (13 studies), self-reported physician diagnosis (7 studies), direct diagnosis by a physician (1 study) or during a medical interview (1 study). The outcome was defined as an incident non-fatal stroke event in nine studies (7 cohort studies, 2 case-control studies), incident fatal stroke event in one cohort study and incident non-fatal or fatal ("mixed") event in 12 studies (all cohort studies). Cohort studies were judged to have a relatively low risk of bias; therefore, we prioritized evidence from these studies, but synthesised evidence from case-control studies as supporting evidence. For the bodies of evidence for both outcomes with any eligible studies (i.e. stroke incidence and mortality), we did not have serious concerns for risk of bias (at least for the cohort studies). Eligible studies were found on the effects of long working hours on stroke incidence and mortality, but not prevalence. Compared with working 35-40 h/week, we were uncertain about the effect on incidence of stroke due to working 41-48 h/week (relative risk (RR) 1.04, 95% confidence interval (CI) 0.94-1.14, 18 studies, 277,202 participants, I² 0%, low quality of evidence). There may have been an increased risk for acquiring stroke when working 49-54 h/week compared with 35-40 h/week (RR 1.13, 95% CI 1.00-1.28, 17 studies, 275,181participants, I² 0%, p 0.04, moderate quality of evidence). Compared with working 35-40 h/week, working ≥55 h/week may have led to a moderate, clinically meaningful increase in the risk of acquiring stroke, when followed up between one year and 20 years (RR 1.35, 95% CI 1.13 to 1.61, 7 studies, 162,644 participants, I² 3%, moderate quality of evidence). Compared with working 35-40 h/week, we were very uncertain about the effect on dying (mortality) of stroke due to working 41-48 h/week (RR 1.01, 95% CI 0.91-1.12, 12 studies, 265,937 participants, I² 0%, low quality of evidence), 49-54 h/week (RR 1.13, 95% CI 0.99-1.29, 11 studies, 256,129 participants, I² 0%, low quality of evidence) and 55 h/week (RR 1.08, 95% CI 0.89-1.31, 10 studies, 664,647 participants, I² 20%, low quality of evidence). Subgroup analyses found no evidence for differences by WHO region, age, sex, socioeconomic status and type of stroke. Sensitivity analyses found no differences by outcome definition (exclusively non-fatal or fatal versus "mixed") except for the comparison working ≥55 h/week versus 35-40 h/week for stroke incidence (p for subgroup differences: 0.05), risk of bias ("high"/"probably high" ratings in any domain versus "low"/"probably low" in all domains), effect estimate measures (risk versus hazard versus odds ratios) and comparator (exact versus approximate definition).

CONCLUSIONS

We judged the existing bodies of evidence for human evidence as "inadequate evidence for harmfulness" for all exposure categories for stroke prevalence and mortality and for exposure to 41-48 h/week for stroke incidence. Evidence on exposure to 48-54 h/week and ≥55 h/week was judged as "limited evidence for harmfulness" and "sufficient evidence for harmfulness" for stroke incidence, respectively. Producing estimates for the burden of stroke attributable to exposures to working 48-54 and ≥55 h/week appears evidence-based, and the pooled effect estimates presented in this systematic review could be used as input data for the WHO/ILO Joint Estimates. PROTOCOL IDENTIFIER: https://doi.org/10.1016/j.envint.2018.06.016.

PROSPERO REGISTRATION NUMBER

CRD42017060124.