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Dive into the research topics where Masanori Nagao is active.

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Featured researches published by Masanori Nagao.


European Journal of Clinical Nutrition | 2012

Meat consumption in relation to mortality from cardiovascular disease among Japanese men and women

Masanori Nagao; Hiroyasu Iso; Kazumasa Yamagishi; Chigusa Date; Akiko Tamakoshi

Background/objectives:Although high or low (no) meat consumption was associated with elevated or reduced mortality from cardiovascular disease, respectively, few studies have investigated the association between moderate meat consumption and cardiovascular disease. We aimed to evaluate the associations between moderate meat consumption and cardiovascular disease mortality.Subjects/methods:We conducted a prospective cohort study of 51 683 Japanese (20 466 men and 31 217 women) aged 40–79 years living in all of Japan (The Japan Collaborative Cohort Study; JACC Study). Consumptions of meat (beef, pork, poultry, liver and processed meat) were assessed via a food frequency questionnaire administrated at baseline survey. Hazard ratios (HRs) of mortality from cardiovascular disease were estimated from Cox proportional hazards regression models according to quintiles of meat consumption after adjustment for potential confounding variables.Results:During 820 076 person-years of follow-up, we documented 2685 deaths due to total cardiovascular disease including 537 ischemic heart diseases and 1209 strokes. The multivariable HRs (95% confidence interval) for the highest versus lowest quintiles of meat consumption (77.6 versus 10.4 g/day) among men were 0.66 (0.45–0.97) for ischemic heart disease, 1.10 (0.84–1.43) for stroke and 1.00 (0.84–1.20) for total cardiovascular disease. The corresponding HRs (59.9 versus 7.5 g/day) among women were 1.22 (0.81–1.83), 0.91 (0.70–1.19) and 1.07 (0.90–1.28). The associations were similar when the consumptions of red meat, poultry, processed meat and liver were examined separately.Conclusion:Moderate meat consumption, up to ∼100 g/day, was not associated with increased mortality from ischemic heart disease, stroke or total cardiovascular disease among either gender.


Stroke | 2015

Effects of Stroke Education of Junior High School Students on Stroke Knowledge of Their Parents Tochigi Project

Kosuke Matsuzono; Chiaki Yokota; Hidehiro Takekawa; Tomonori Okamura; Naomi Miyamatsu; Hirofumi Nakayama; Kunihiro Nishimura; Satoshi Ohyama; Akiko Ishigami; Kosuke Okumura; Kazunori Toyoda; Yoshihiro Miyamoto; Kazuo Minematsu; Daisuke Sugiyama; Masanori Nagao; Akiko Morimoto; Aya Kadota; Nobue Takizawa; Kayo Ieiri; Teruki Watanabe

Background and purpose— Educating the youth about stroke is a promising approach for spreading stroke knowledge. The aim of this study was to verify communication of stroke knowledge to parents by educating junior high school students about stroke. Methods— We enrolled 1127 junior high school students (age, 13–15 years) and their parents in the Tochigi prefecture, Japan. All students received a stroke lesson, watched an animated cartoon, and read the related Manga comic as educational aids. The students took back home the Manga and discussed what they learned with their parents. Questionnaires on stroke knowledge were given to all at baseline and immediately after the lesson. Results— A total of 1125 students and 915 parents answered the questionnaires. In the students, the frequency of correct answers increased significantly for all questions on stroke symptoms except for headache, and for all questions on risk factors after the lesson. In the parents, the correct answer rates increased for stroke symptoms except for headache and numbness in one side of the body, and for all questions on risk factors except for hypertension. Ninety-one percent of students and 92.7% of parents correctly understood the Face, Arm, Speech, and Time (FAST) mnemonic after the lesson. Conclusions— Improvement of stroke knowledge immediately after the stroke lesson was observed in parents as well as their children, which indicated that our teaching materials using the Manga was effective in delivering the stroke knowledge to parents through their children.


Journal of Epidemiology | 2012

Relation of Serum α- and γ-Tocopherol Levels to Cardiovascular Disease-Related Mortality Among Japanese Men and Women

Masanori Nagao; Yuri Moriyama; Kazumasa Yamagishi; Hiroyasu Iso; Akiko Tamakoshi

Background There is limited evidence regarding the relationship between serum tocopherol levels and cardiovascular disease. Methods We conducted a nested case-control study as part of the Japan Collaborative Cohort Study for evaluation of cancer risk (JACC Study). Baseline serum samples were collected from 39 242 participants (age range, 40–79 years) between 1988 and 1990. During the 13-year follow-up, there were 530 stroke deaths (302 ischemic strokes and 210 hemorrhagic strokes) and 211 deaths from coronary heart disease. Controls were matched for sex, age, and area of residence. Results Serum α-tocopherol level was not associated with any type of cardiovascular death in men; however, in women, it was inversely associated with total stroke mortality and hemorrhagic stroke mortality. The multivariate odds ratio (95% CI) for the highest versus the lowest quintile of serum α-tocopherol levels among women was 0.35 (0.16–0.77; P for trend = 0.009) for total stroke and 0.26 (0.07–0.97; P for trend = 0.048) for hemorrhagic stroke. Serum γ-tocopherol was inversely associated with ischemic stroke mortality in men but positively associated with hemorrhagic stroke mortality in women. The respective multivariate odds ratios (95% CI) for the highest versus the lowest quintile and for a 1-standard deviation increment in γ-tocopherol level were 0.48 (0.22–1.06; P for trend = 0.07) and 0.77 (0.58–1.02), respectively, for ischemic stroke in men and 3.10 (0.95–10.12; P for trend = 0.052) and 1.49 (1.04–2.13) for hemorrhagic stroke in women. Conclusions Among women, hemorrhagic stroke mortality was inversely associated with serum α-tocopherol and positively associated with serum γ-tocopherol. These findings are due in part to the antioxidative and antithrombotic activities of these tocopherols.


Atherosclerosis | 2014

Serum coenzyme Q10 and risk of disabling dementia: The Circulatory Risk in Communities Study (CIRCS)

Kazumasa Yamagishi; Ai Ikeda; Yuri Moriyama; Choy-Lye Chei; Hiroyuki Noda; Mitsumasa Umesawa; Renzhe Cui; Masanori Nagao; Akihiko Kitamura; Yorihiro Yamamoto; Takashi Asada; Hiroyasu Iso

OBJECTIVE To examine whether coenzyme Q10, a potent antioxidant, is associated with risk of dementia, which has not yet been elucidated. APPROACH AND RESULTS We performed a case-control study nested in a community-based cohort of approximately 6000 Japanese aged 40-69 years at baseline (1984-1994). Serum coenzyme Q10 was measured in 65 incident cases of disabling dementia with dementia-related behavioral disturbance or cognitive impairment incident between 1999 and 2004, and in 130 age-, sex- and baseline year-matched controls. Serum coenzyme Q10 was inversely associated with dementia: the multivariate odds ratios (95% confidence intervals) were 0.68 (0.26-1.78), 0.92 (0.33-2.56), and 0.23 (0.06-0.86) for individuals with the second, third, and highest quartiles of coenzyme Q10, respectively, as compared with the lowest quartile (P for trend = 0.05). A similar association was found for the coenzyme Q10/total cholesterol ratio: the respective ORs were 0.67 (0.25-1.78), 0.73 (0.28-1.92), and 0.21 (0.05-0.90) (P for trend = 0.04). CONCLUSIONS Serum coenzyme Q10 levels were inversely associated with risk of disabling dementia.


BMJ Open | 2017

Effects of a school-based stroke education program on stroke-related knowledge and behaviour modification-school class based intervention study for elementary school students and parental guardians in a Japanese rural area

Suzuka Kato; Tomonori Okamura; Kazuyo Kuwabara; Hidehiro Takekawa; Masanori Nagao; Mitsumasa Umesawa; Daisuke Sugiyama; Naomi Miyamatsu; Tenyu Hino; Shinichi Wada; Takuro Arimizu; Toru Takebayashi; Gen Kobashi; Koichi Hirata; Chiaki Yokota; Kazuo Minematsu

Objectives This study aimed to determine the effect of a stroke education programme on elementary school students and their parental guardians in a rural area in Japan that has high stroke mortality. Design School class based intervention study. Setting Eleven public elementary schools in Tochigi Prefecture, Japan. Participants 268 students aged 11–12 years and 267 parental guardians. Interventions Students received lessons about stroke featuring animated cartoons and were instructed to communicate their knowledge about stroke to their parental guardians using material (comic books) distributed in the lessons. Stroke knowledge (symptoms, risk factors and attitude towards stroke) and behavioural change for risk factors were assessed at baseline, immediately after the programme and at 3 months. We also evaluated behavioural change for risk factors among parental guardians. Results The percentage of students with all correct answers for stroke symptoms, risk factors and the recommended response to stroke was significantly increased at 3 months P<0.001). We observed a significant increase in the percentage of guardians who chose all correct symptoms (P<0.001: 61.0% vs 85.4%) and risk factors (P<0.001: 41.2% vs 59.9%) at 3 months compared with baseline. The percentage of parental guardians with a high behavioural response to improving risk factors was significantly increased at 3 months compared with baseline (P<0.001). Conclusions In a rural population with high stroke mortality, stroke education can improve knowledge about stroke in elementary school students and their parental guardians. Ethics and dissemination We conducted the intervention as a part of compulsory education; this study was not a clinical trial. This study was approved by the Ethics Committee of the National Cerebral and Cardiovascular Center (M27-026).


Journal of Epidemiology | 2017

Personal status of general health checkups and medical expenditure: A large-scale community-based retrospective cohort study

Yasuo Haruyama; Takako Yamazaki; Motoki Endo; Rika Kato; Masanori Nagao; Mitsumasa Umesawa; Toshimi Sairenchi; Gen Kobashi

Background We sought to clarify the association between the personal utilization of general health checkups (GHCs) and medical expenditures (MEs) in a middle-aged Japanese population. Methods A retrospective cohort study was conducted. Subjects were 33,417 residents (15,819 males and 17,598 females) aged 48 years or older in 2010 who were invited to undergo GHCs every year. Official records on GHCs from 2002 to 2007 and MEs from 2008 to 2010 were provided by Soka City, Saitama Prefecture, Japan. The utilization of GHCs was divided into zero times (non-utilizers), 1–3 times (low-frequency utilizers), and 4–6 times (high-frequency utilizers). Tweedie distributions in the generalized linear model were used to analyze the association between MEs and the subgroups of GHC utilization after adjustment for age and sex. Results Of the 33,417 subjects, 20,578 (61.6%) were non-utilizers, 5,777 (17.3%) were low-frequency utilizers, and 7,062 (21.1%) were high-frequency utilizers, based on the attendance to GHCs from 2002 to 2007. Compared with the non-utilizers, the high-frequency utilizers showed significantly higher outpatient MEs (JPY394,700 vs. JPY373,100). The low- and high-frequency utilizers showed significantly lower inpatient MEs (JPY224,000 and JPY181,500 vs. JPY309,300) and total MEs (JPY610,600 and JPY580,700 vs. JPY689,600) than the non-utilizers based on the pooled data from 2008 to 2010. Conclusions This study suggests that the outpatient MEs rise when annual GHCs are increasingly attended (not including the GHC cost), but inpatient and total MEs are lower. To reduce MEs, increasing the rates of attendance at GHCs by the general public may be important.


Clinical & Developmental Immunology | 2018

Lipid and Bile Acid Dysmetabolism in Crohn’s Disease

Koji Uchiyama; Hisashi Kishi; Wataru Komatsu; Masanori Nagao; Shuji Ohhira; Gen Kobashi

Crohns disease is one of the systemic autoimmune diseases. It commonly affects the small intestine and colon but may involve any portion of the gastrointestinal tract from the mouth to the anus. The most affected area by Crohns disease is the distal part of the small intestine, in which the bile acid molecules are most efficiently reabsorbed. Bile acids form mixed micelles together with fatty acids, which function as a transport vehicle to deliver fatty acids to the apical membrane of enterocytes for absorption. Therefore, if the terminal ileum is impaired, bile acid malabsorption may occur, which may cause congenital diarrhoea in Crohns disease. Similarly, the impairment of the terminal ileum also induces fatty acid malabsorption, which may influence the role of fatty acids in Crohns disease. In contrast, a recent study reported that multidrug resistance protein 1 (MDR1) regulated effector T-cell function in the ileum from bile acid-driven oxidative stress and MDR1 loss of function in a subset of patients with Crohns disease. However, the role of consumption of fatty acids in Crohns disease remains to be fully elucidated. This review is aimed at providing an overview of some recent developments in research of Crohns disease from comprehensive perspective with a focus on the connection between disease location and behaviour, lipid diets, and bile acid malabsorption.


BMJ Open | 2018

Association between dipstick proteinuria and hearing impairment in health check-ups among Japanese workers: a cross-sectional study

Mitsumasa Umesawa; Mikako Hara; Toshimi Sairenchi; Yasuo Haruyama; Masanori Nagao; Munehiro Matsushita; Gen Kobashi

Objective Prevention of hearing impairment is important because it is difficult to recover from it. Epidemiological studies have examined the risk factors for hearing impairment; however, the association between dipstick proteinuria and hearing impairment has not been previously examined. This study aimed to clarify the association between dipstick proteinuria and hearing impairment. Design Cross-sectional study. Setting Office and factory workers from all over Japan. Participants The total number of subjects was 7005. All were employees of the same company. Of these, we recruited 6192 subjects who underwent dipstick urine test and hearing test by audiometry in annual health check-ups (mean age 44.9 years, men 88.3%). Primary outcomes Hearing tests were performed at two frequencies (1 kHz, 4 kHz) as prescribed by law in Japan. We defined the inability of subjects to respond to 30 dB at 1 kHz and/or 40 dB at 4 kHz as overall moderate hearing impairment. In addition, we defined moderate hearing impairment at 1 kHz (4 kHz) as an abnormal finding at 1 kHz (4 kHz). We examined the associations between degree of dipstick proteinuria and hearing impairment after adjustment for age, sex, body mass index, hypertension, diabetes mellitus, serum creatinine level and history of noisy work environment. Results Overall moderate hearing impairment was noted in 324 subjects (5.2%). Of these, 107 subjects (1.7%) had moderate hearing impairment at 1 kHz and 278 subjects (4.5%) at 4 kHz. Dipstick proteinuria was significantly associated with overall moderate hearing impairment, as well as moderate hearing impairment at both 1 kHz and 4 kHz. The prevalence of overall moderate hearing impairment among subjects with proteinuria ≥2+ was 23.5%, while that among subjects without proteinuria was 5.2% (p<0.01). Conclusions Dipstick proteinuria was associated with moderate hearing impairment in Japanese workers.


Journal of Epidemiology | 2017

Impact and attribute of each obesity-related cardiovascular risk factor in combination with abdominal obesity on total health expenditures in adult Japanese National Health insurance beneficiaries: The Ibaraki Prefectural health study.

Toshimi Sairenchi; Hiroyasu Iso; Kazumasa Yamagishi; Fujiko Irie; Masanori Nagao; Mitsumasa Umesawa; Yasuo Haruyama; Gen Kobashi; Hiroshi Watanabe; Hitoshi Ota

Background The aim of this study was to examine the attribution of each cardiovascular risk factor in combination with abdominal obesity (AO) on Japanese health expenditures. Methods The health insurance claims of 43,469 National Health Insurance beneficiaries aged 40–75 years in Ibaraki, Japan, from the second cohort of the Ibaraki Prefectural Health Study were followed-up from 2009 through 2013. Multivariable health expenditure ratios (HERs) of diabetes mellitus (DM), high low-density lipoprotein cholesterol (LDL-C), low high-density lipoprotein cholesterol (HDL-C), and hypertension with and without AO were calculated with reference to no risk factors using a Tweedie regression model. Results Without AO, HERs were 1.58 for DM, 1.06 for high LDL-C, 1.27 for low HDL-C, and 1.31 for hypertension (all P < 0.05). With AO, HERs were 1.15 for AO, 1.42 for DM, 1.03 for high LDL-C, 1.11 for low HDL-C, and 1.26 for hypertension (all P < 0.05, except high LDL-C). Without AO, population attributable fractions (PAFs) were 2.8% for DM, 0.8% for high LDL-C, 0.7% for low HDL-C, and 6.5% for hypertension. With AO, PAFs were 1.0% for AO, 2.3% for DM, 0.4% for low HDL-C, and 5.0% for hypertension. Conclusions Of the obesity-related cardiovascular risk factors, hypertension, independent of AO, appears to impose the greatest burden on Japanese health expenditures.


BMC Cardiovascular Disorders | 2016

The relationship between sodium concentrations in spot urine and blood pressure increases: a prospective study of Japanese general population: the Circulatory Risk in Communities Study (CIRCS)

Mitsumasa Umesawa; Kazumasa Yamagishi; Hiroyuki Noda; Ai Ikeda; Shinobu Sawachi; Isao Muraki; Choy-Lye Chei; Renzhe Cui; Masanori Nagao; Tetsuya Ohira; Tomoko Sankai; Takeshi Tanigawa; Akihiko Kitamura; Masahiko Kiyama; Hiroyasu Iso

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Gen Kobashi

Dokkyo Medical University

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Yasuo Haruyama

Dokkyo Medical University

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