Effects of Cooking Methods on Caffeoylquinic Acids and Radical Scavenging Activity of Sweet Potato.

The effects of cooking methods, including steaming, deep-frying, and baking, on the phenolic content, 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, and isomerization of caffeoylquinic acids in sweet potato were investigated. A high correlation was observed between antioxidant capacity and total phenolic content. Deep-frying treatment resulted in higher antioxidant capacity with increasing heating time. The major phenolic components of raw sweet potat were 5-caffeoylquinic acid (CQA) and 3,5-dicaffeoylquinic acid (diCQA), which were reduced by heat treatment due to the isomerization of 5-CAQ to 3- and 4-CQA, and 3,5-diCQA to 3,4- and 4,5-diCQA. Moreover, 5-CQA was more stable than 3,5-diCQA even at 100 °C. Our results demonstrated that by controlling the cooking temperature and time, new bioactive compounds such as mono- and diCQA derivatives can be produced from sweet potato. These data indicate a potential approach for the development of new functional foods from sweet potato by controlling cooking temperature and time.

Cost-effectiveness analysis of COVID-19 booster vaccination with BNT162b2 in Japan.

BACKGROUND: The aim of this study was to evaluate the public health and economic impact of the COVID-19 booster vaccination with BNT162b2 in Japan during an Omicron-dominant period from early 2022. RESEARCH DESIGN AND METHODS: A combined cohort Markov decision tree model estimated the cost-effectiveness of annual or biannual booster vaccination strategies compared to no booster vaccination for those aged 65 years and above, and those aged 60-64 years at high risk as the base case. The societal perspective was primarily considered. We also examined other target populations with different age and risk groups. Sensitivity and scenario analyses with alternative inputs were performed. RESULTS: Annual and biannual vaccination strategies were dominant from the societal perspective in the base case. Incremental Cost Effectiveness Ratios (ICERs) from the payer perspective were JPY 1,752,499/Quality Adjusted Life Year (QALY) for annual vaccination and JPY 2,831,878/QALY for biannual vaccination, both less than the threshold value in Japan (JPY 5 million/QALY). The results were consistent even when examining other target age and risk groups. All sensitivity and scenario analyses indicated that ICERs were below JPY 5 million/QALY. CONCLUSIONS: Booster vaccination with the COVID-19 vaccine BNT162b2 is a dominant strategy and beneficial to public health in Japan.

Ameliorative Effects of Anthocyanin Metabolites on Western Diet-Induced NAFLD by Modulating Co-Occurrence Networks of Gut Microbiome.

Anthocyanins (Acn) have been reported to have preventive effects on Western diet (WD)-induced non-alcoholic fatty liver disease (NAFLD). However, the amount of Acn that reached the bloodstream were less than 1%, suggesting that anthocyanin metabolites (Acn-M) in the gut may contribute to their in vivo effects. This study is focused on a gut microbiota investigation to elucidate the effect of two major Acn-M, protocatechuic acid (PC) and phloroglucinol carboxaldehyde (PG), on NAFLD prevention. C57BL/6N male mice were divided into five groups and fed with a normal diet (ND), WD, WD + 0.5% PC, WD + 0.5% PG and WD + a mixture of 0.25% PC + 0.25% PG (CG) for 12 weeks. The results revealed that WD-fed mice showed a significant increase in final body weight, epididymis fat weight, liver weight and fat accumulation rate, serum total cholesterol, alanine aminotransferase, monocyte chemoattractant protein 1, and 2-thiobarbituric acid reactive substances. At the same time, these indices were significantly decreased by Acn-M in the order of PG, CG > PC. In particular, PG significantly decreased serum glucose and insulin resistance. Gut microbiome analysis revealed that PG significantly increased the relative abundance of Parabacteroides, Prevotella, Prevotella/Bacteroides ratio, and upregulated glucose degradation pathway. Interestingly, the co-occurrence networks of Lachnospiraceae and Desulfovibrionaceae in the PC and PG groups were similar to the ND group and different to WD group. These data suggest that PC and PG were able to recover the gut microbiome networks and functions from dysbiosis caused by WD. Therefore, PG might act as a master metabolite for anthocyanins and prevent WD-induced NAFLD and gut dysbiosis.

Multivariate Profiling of Metabolites and Volatile Organic Compounds in Citrus depressa Hayata Fruits from Kagoshima, Okinawa, and Taiwan.

Citrus depressa Hayata is a small-fruit citrus species; it is indigenous to Kagoshima, Okinawa, and Taiwan. The metabolites and volatile organic compounds (VOCs) that affect the flavor of its fruits have not been investigated based on geographical origin. In the present study, we investigated the metabolite and VOC profiles of 18 C. depressa cultivation lines from these regions. Multivariate analysis revealed differences in the metabolites of C. depressa based on its cultivation origins; variations in sugar, sugar alcohol, and amino acid contents were also observed. Fruits from Kagoshima and Okinawa had higher galactinol, trehalose, xylose, glucose, and sucrose intensities than fruits from Taiwan (log2-fold change; 2.65-3.44, 1.68-2.13, 1.37-2.01, 1.33-1.57, and 1.07-1.43, respectively), whereas the Taiwanese lines contained higher leucine, isoleucine, serine, and alanine. In contrast to the Taiwanese Nantou line, other cultivation lines had comparable total VOC contents, and the VOCs of all lines were dominated by limonene, γ-terpinene, and p-cymene. Accordingly, the highest VOC intensities were recorded in the Nantou line, which was followed by Shikunin sweet (Kagoshima) and Taoyuan (Taiwan) (log10 normalize concentration; 5.11, 3.08, and 3.01, respectively). Moreover, multivariate analysis plots elucidated the difference in the VOCs of Ishikunibu (Okinawa), Shikunin sweet, and Taoyuan and between those of most Kagoshima and Okinawa cultivation lines. These results suggest that both the cultivation line and origin influence the metabolites and VOCs of C. depressa, thus possibly affecting its flavor quality; the data provide a valuable insight for utilizing C. depressa of different cultivation lines and origins to produce foods and beverages.

Effects of processing methods on the aroma constituents of hihatsumodoki (Piper retrofractum Vahl).

Hihatsumodoki (Piper retrofractum Vahl) is a traditional spice from Okinawa (Japan) that can be processed in different ways to create the desired flavor. Herein, we examined the effects of processing (sun-drying, oven-drying, roasting, and steaming) on the volatile aroma constituents of hihatsumodoki fruits. Among the 106 chromatographic peaks observed in total, 58 were assigned to known aroma compounds. The relative contents of terpenes, for example, linalool, ß-caryophyllene, α-caryophyllene, and germacrene D, ranged from 57.6% to 88.1%. Sun-drying decreased the content of aldehydes such as hexanal and trans-2-hexenal but did not significantly affect the total content of aroma compounds. The amount of aroma compounds released during oven-drying and roasting increased with temperature up to a certain point (90°C) and decreased at an excessively high temperature of 180°C. High-temperature roasting generated Maillard reaction products such as furans and furanones, which could impart sweet caramel odors. Steamed fruits had the lowest content of aroma compounds, which was ascribed to the loss of these compounds to vapor. Meanwhile, drying steamed fruits resulted in an approximately 3.6-fold increase in their aroma compound content, and the content of sesquiterpenes in the steamed-dried fruits was similar to that in fruits exposed to high temperatures. The effects of processing on aroma quality were visualized using multivariate statistical analysis. The aroma characteristics of roasted (180°C), steamed, and steamed-dried fruits were different from those of the control. The combined findings provide useful information for the selection of processing methods to achieve the desired flavor of hihatsumodoki. Practical Application: This study reveals the effects of different processing methods on the aroma profile of hihatsumodoki (Piper retrofractum Vahl), a subtropical spice from Okinawa (Japan). The results facilitate the selection of preferred hihatsumodoki flavors for household and industrial applications in foods and beverages. In addition, they inspire research on the processing-induced flavor changes of other tropical or subtropical spices.

Composition of Minerals and Volatile Organic Components of Non-Centrifugal Cane Sugars from Japan and ASEAN Countries.

Non-centrifugal cane sugar (NCS) is an unrefined dehydrated form of sugar syrup produced worldwide. To date, there is a lack of differentiation in the key nutrients and flavor qualities of NCS products among countries, which makes it difficult for interested parties to select NCSs suitable for their needs. This study aimed to evaluate the minerals and volatile organic components (VOCs) in NCS products from Japan and ASEAN countries. Mineral components were determined using inductively coupled plasma atomic emission spectroscopy (ICP-AES). VOCs and their aroma profiles were examined using gas chromatography-mass spectrophotometry (GC-MS) and MS-e-nose analyses, respectively. The total minerals content in Japanese NCSs ranged from 228.58 to 1347.53 mg/100 g, comprising K, Ca, Mg, P, and Na (69.1, 16.6, 7.9, 4.5, and 3.2%, respectively); their average total amounts were as high as those of Malaysia and Indonesia origins (962.87, 984.67, and 928.47 mg/100 g, respectively). Forty-four VOCs were identified, of which concentrations of pyrazines, furans, and pyranones varied significantly among the NCSs. Additionally, the MS-e-nose analysis provided a multivariate differentiation profile of the NCS products based on differences in the intensities of the VOC ion masses. Nine statistical clusters were presented, wherein certain NCS products of ASEAN origin had volatile profiles comparable to those of the Japanese products. These outcomes suggest that the origin of production greatly influences the mineral and VOC compositions of NCS, affecting their quality traits.

Associations Between Adult Attention-Deficit/Hyperactivity Disorder (ADHD) Traits and Sociodemographic Characteristics in Japanese Workers.

Purpose: Most previous studies that described associations between adult attention-deficit/hyperactivity disorder (ADHD) and sociodemographic characteristics were focused on individuals diagnosed with ADHD, and few studies investigated ADHD traits in the general population. Additionally, some workers, who experienced no problems while at university and successfully graduated from university, developed ADHD traits after finding employment. This study described associations between ADHD traits and sociodemographic characteristics among Japanese workers who were university graduates. Patients and Methods: Participants were randomly selected workers (n=1240) from across Japan who completed a self-administered online survey. ADHD traits were measured using an adult ADHD Self-report Scale, with scoring rules applied to reflect the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria. Information was collected on sociodemographic characteristics including sex, age, socioeconomic status, working time, and health-related behaviors. We performed partial correlation analysis to estimate trend associations and used analysis of covariance to compare adjusted averages. This model was adjusted for all variables. Results: Males had higher levels of ADHD traits than females (p = 0.001), and younger age was associated with higher levels of ADHD traits (p < 0.001). Workers with low incomes had higher levels of ADHD traits than workers with high incomes (p = 0.009). More frequent consumption of midnight meals was associated with higher levels of ADHD traits (p < 0.001), although there were no differences for breakfast, lunch, and dinner. Those who did not get enough rest from sleep had higher levels of ADHD traits (p = 0.007). Conclusion: Results for high levels of ADHD traits among workers were consistent with previous studies for adults diagnosed with ADHD, even though all participants had successfully graduated from university. Assessment of these ADHD traits may support prevention of health deterioration related to these ADHD traits.

Antiproliferative Effect of N-Heterocyclo-Coumarin Derivatives against Multidrug-Resistant Cells.

Chemotherapy refers principally to the use of small molecules to treat cancer, and natural product derivatives have been main sources of clinically using anticancer drugs. While the coumarin skeleton does not inhibit cell growth, its derivatives are often active, and numerous coumarins have been examined for antiproliferative activity against human cancer cell lines. In this study, 16 novel coumarin derivatives (1, 1a-5a, 1b, 2b, 6b, 7b, 8-13) with attached N-heterocycles, including aminopyrrolidine, aminopiperidine, aminoazepane, and indoline, were prepared and ultimately esterified or amidated with alcohols or amines, respectively. All synthesized N-heterocycles containing coumarin derivatives with alcohols, amines, and carboxylic acids were assessed for antiproliferative activity against several human cancer cell lines, containing triple-negative breast cancer (TNBC) as well as a P-glycoprotein (P-gp) overexpressing multidrug-resistant (MDR) KB subline KB-VIN. Five coumarin derivatives (3a-5a, 12, 13) showed no effect (IC50 >40 µM) against all tested cell lines. In contrast, derivative 1a showed broad-spectrum activity against four cell lines, while 1b and 10 were nearly twice as selective for KB-VIN cells as the parent KB. The coumarin derivatives 1a, 1b, and 10 were optimal for antiproliferative activity in this study and could provide a new avenue for overcoming MDR tumors. Derivatives 1a, 1b, and 10 showed MDR cell-selective antiproliferative activity, indicating that N-heterocycle-coumarins exert previously unexplored bioactivity with selective action on MDR cancer cells.

Rational design and structure-activity relationship studies reveal new esterified C20-diterpenoid alkaloid analogues active against MCF-7 human breast cancer cells.

Although various diterpenoid alkaloids have been evaluated recently for antiproliferative activity against human tumor cell lines, little information is available regarding the antiproliferative effects of C20-diterpenoid alkaloids against MCF-7 cells. Six new diterpenoid alkaloid derivatives (13, 14, 22, 23, 25, 26) were prepared by C-11 and 15 esterification of kobusine (6). The natural parent alkaloid 6 and all synthesized derivatives (7 - 27, 12a, 15a, 15b, 18a, 18b) were evaluated for antiproliferative activity against MCF-7 cells. The structure-based design strategy resulted in an initial lead derivative, 11,15-dibenzoylkobusine (7; IC50 8.6 µM). Subsequent synthesized 11,15-diacylkobusine derivatives (9, 16, 20, 21, 23, 25, and 26) showed substantially increased suppressive effects against the MCF-7 cell line (IC50 2.3-4.4 µM). In contrast, parent alkaloid 6, two 11-acylkobusine derivatives (15a, 18a), and two 15-acylkobusine derivatives (15b, 18b) showed no effect. 11,15-Diacylation appears to be critical for producing antiproliferative activity in this alkaloid class and could introduce a new avenue in overcoming breast cancer cell proliferation using natural product derivatives. In a preliminary mechanism of action study, representative derivatives (5, 8, 9, and 17) decreased cyclin D1 mRNA expression.

Characteristics of needlestick and sharps injuries of the hands in the operating room among orthopedic surgeons in Japan.

Among the reports on needlestick and sharps injuries (NSIs), many are orthopedic-related due to the frequent use of sharp devices such as pins and wires. This study aimed to identify high-risk instruments, the most common injury sites for each instrument, and the circumstances of NSIs of the hand during orthopedic surgeries in Japan. Incidents of exposure to blood or bodily fluids among physicians during orthopedic surgeries reported to the Japan-EPINet between 2000 and 2015 were included in this study. The four most common devices were identified and the associations among years of experience, equipment users, and injured sites were analyzed. We identified 666 cases of NSIs affecting orthopedic surgeons in the operating room. The instrument most frequently responsible for NSIs was suture needles, which were involved in 265 cases (39.7%). The second most common instrument was pins/wires, which was involved in 111 cases (16.6%). NSIs of the hands of orthopedic surgeons were frequently caused by suture needles used in all surgeries, but relatively often caused by orthopedic devices. Orthopedic surgeons must be aware that they are at risk of NSIs and must take appropriate measures and always be cautious when performing surgery, regardless of their years of experience.

Associations between Depressive Symptoms, Work Environment, and Lifestyle in <40-year-old Male Orthopedic Physicians in Japan.

Introduction: Efforts are being made to reduce doctors' working hours and implement reforms in the way doctors work. This study aims to determine the associations between depressive symptoms and work environment/lifestyle among <40-year-old male orthopedic physicians in Japan. Methods: Participants were 1,343 male orthopedic physicians selected from a survey (N = 25,139) of all regular members conducted in 2019 by the Japanese Orthopaedic Association. Participants completed the Quick Inventory of Depressive Symptomatology and provided information about total working hours, number of on-call/night duties, number of patient complaints received, smoking habits, exercise habits, and sleep time. Results: Of the participants, 6.6% had depressive symptoms. Factors associated with depressive symptoms were total working hours of ≥80 h per week (80-99 h: adjusted odds ratio [AOR] = 2.06; 95% confidence interval [CI], 1.02-4.18; ≥100 h: AOR = 3.89; 95% CI, 1.92-7.88), one or more unreasonable patient demands/complaints in the previous 6 months (AOR = 1.61; 95% CI, 1.00-2.60), current smoking (AOR = 2.98), no sweat-inducing exercise sessions of ≥30 min per week in the previous month (AOR = 2.50), and an average of <6 h of sleep per night in the previous month (AOR = 2.15). Conclusions: Work factors at the main medical institution (i.e., total working hours of ≥80 h per week) were associated with depressive symptoms. In addition, associations between depressive symptoms and unhealthy living conditions, such as smoking habits, lack of exercise, and <6 h of sleep per night, were observed.

Occupation- and industry-specific cancer mortality among Japanese women from 1980 to 2015.

BACKGROUND: The number of women in Japan who continue working after childbirth is on the rise. Over the past few years, Japan's cancer mortality rate has increased. About 50% of all cancer deaths among Japanese women aged 25-64 are caused by lung, gastric, pancreatic and colorectal cancers. This study aims to examine the difference in mortality risk for key cancers among women and explore the effect of the economic crisis in the mid-1990s separately for occupational and industrial categories. METHODS: Data from 1980 to 2015 were gathered from the Japanese Population Census and National Vital Statistics conducted in the same year. A Poisson regression analysis was used to estimate mortality risk and mortality trends for lung, gastric, pancreatic and colorectal cancer among Japanese working women aged 25-64 years. RESULTS: Across most industrial and occupational groups, the trends in age-standardised cancer mortality rate for women have declined. Workers in management, security and transportation have a higher cancer mortality risk than sales workers. The risk of death from all four cancers is higher for workers in the mining and electricity industries than for wholesale and retail workers. CONCLUSION: To improve the health and well-being of employed Japanese women, it is crucial to monitor cancer mortality trends. Using these population-level quantitative risk estimates, industry- and occupation-specific prevention programmes can be developed to target women at higher cancer risk and enable the early detection and treatment of cancer.

Repression Effects of Hydrolysates from Hen-Egg Proteins on Amyloid Fibril Formation.

Amyloid fibrils, which are formed from aggregates of aberrant proteins, can cause various forms of amyloidosis (including Alzheimer's disease). Such disorders often occur in elderly populations and are suspected to be lifestyle related. Thus, it has been speculated that some foodstuffs could be beneficial for preventing amyloidosis. In this study, we determine whether fibril formation by the hen egg white lysozyme (HEWL) could be inhibited by conducting a thioflavin T assay followed by fluorescence and electron microscopy observations. The results demonstrated that four peptide specimens prepared by the hydrolysis of crude proteins from the egg white, egg yolk, chalazae, and eggshell membrane of hen eggs effectively inhibited HEWL fibril formation. Among the four specimens, peptides from chalazae exhibited the highest preventive ability. The superiority of chalaza peptides was also observed when fibril formation was assayed using a full-length human lysozyme and human amyloid ß peptide 1-42, which is the key factor for the development of Alzheimer's disease. Our study of the fibrillization of the human lysozyme also showed that metal ions (Zn2+, Ca2+, Co2+, Mn2+ and Al3+) promoted fibrillization, and their effects were abolished by the peptide specimens (especially by chalaza peptides). Thus, we conclude that chicken-egg proteins could be a convenient source of therapeutic materials for amyloidosis.

Difference in Mortality Rates by Occupation in Japanese Male Workers Aged 25 to 64 Years from 1980 to 2015.

This study examines the trends in mortality among Japanese working men, across various occupational categories, from 1980 to 2015. A Poisson model of trend, occupational category, and step variable was analysed for eight occupational categories separately, by cause, to explore the trends in mortality. This study found a sharp increase in mortality in the late 1990s, especially among professionals and managers. The overall trends in cancer, ischemic heart disease (IHD), cerebrovascular disease (CVD), and suicide mortality decreased across almost all occupational categories from 1980 to 2015, although there was an increasing trend in cancer of 0.5% among managers. Clerical workers had the greatest relative decrease in mortality rates from cancer (-82.9%), IHD (-81.7%), and CVD (-89.1%). Japan continues to make gains in lowering mortality and extending life expectancy, but its workplace culture must improve to ensure that those working at the heart of the Japanese corporate world can also benefit from Japan's progress in health. Mortality rates in working-aged Japanese men have been declining. However, similar declines are not evident among managers, for whom the mortality rate is remaining stable or slightly increasing. There is a need to address the needs of managers and improve workplace environments for these workers.

Stability of hen egg-white lysozyme during embryonic development.

It is of interest to determine whether and how egg-white proteins are maintained in fertile eggs. We previously observed that egg-white ovalbumin attained high stability during embryogenesis. Herein, we observed that the total mass of egg white and that of its gross protein content showed a decrease according to the days of incubation. The total bacteriolytic activity also lowered, in accord with previous observations. We purified lysozyme from egg-white samples on several incubation days. These purified lysozyme proteins were observed to have enzymatic and bacteriolytic activities against Micrococcus lysodeikticus as well as growth-inhibition potency against Staphylococcus aureus. As the embryogenesis proceeded, the purified lysozyme showed changes in Km and Vmax, a small decrease in the denaturation temperature, and symptoms of an increase in surface hydrophobicity. These results indicate that the lysozyme protein maintained its enzymatic and antibacterial activities until the late period of incubation while undergoing slight conformational changes.

Discovery of C20-Diterpenoid Alkaloid Kobusine Derivatives Exhibiting Sub-G1 Inducing Activity.

Although many diterpenoid alkaloids have been evaluated recently for antiproliferative activity against human cancer cell lines, little data have been offered relating to the antiproliferative effects of hetisine-type C20-diterpenoid alkaloids, such as kobusine (1), likewise as their derivatives. A total of 43 novel diterpenoid alkaloid derivatives (2-10, 2b, 3a, 3b, 6a-16a, 7b, 9b, 10b, 13, 15-26, 15b, 18a, 23a, 27a) were prepared by C-11 and -15 esterification of 1. Antiproliferative effects of the natural parent compound (1) and all synthesized kobusine derivatives against human cancer cell lines, including a triple-negative breast cancer (TNBC) cell line as well as a P-glycoprotein overexpressing multidrug-resistant subline, were assessed. The structure-based design strategy resulted in the lead derivative 11,15-dibenzoylkobusine (3; average IC50 7.3 µM). Several newly synthesized kobusine derivatives (particularly, 5-8, 10, 13, 15-26) exhibited substantial suppressive effects against all tested human cancer cell lines. In contrast, kobusine (1), 11,15-O-diacetylkobusine (2), 11-acylkobusine derivatives (3a, 6a, 9a, 11a, 12a, 15a, 27a), and 15-acylkobusine derivatives (2b, 3b, 7b, 9b, 10b, 15b) showed no effect. The most active kobusine derivatives primarily had two specific substitution patterns, C-11,15 and C-11. Notably, 11,15-diacylkobusine derivatives (3, 6-10, 13, 15, 16, 18, 23) were more potent compared with 11- and 15-acylkobusine derivatives (3a, 3b, 6a-10a, 7b, 9b, 10b, 13a, 15a, 15b, 16a, 18a, 23a). Derivatives 13 and 25 induced MDA-MB-231 cells to the sub-G1 phase within 12 h. 11,15-Diacylation of kobusine (1) appears to be crucial for inducing antiproliferative activity in this alkaloid class and could introduce a new avenue to overcome TNBC using natural product derivatives.

Increased Secondary Attack Rates among the Household Contacts of Patients with the Omicron Variant of the Coronavirus Disease 2019 in Japan.

This study investigated the household secondary attack rate (HSAR) of patients with coronavirus disease (COVID-19) during the omicron variant-dominant period. The HSAR of COVID-19 cases during the omicron variant-dominant period (4-20 January 2022) was calculated and compared with the delta variant-dominant period (20 August to 7 November 2021) in Itako, Japan. In Itako, all 47 and 119 samples tested during the omicron and delta variant-dominant periods were negative and positive, respectively, for the L452R mutation. We used a generalized estimating equation regression model. The HSAR was 31.8% (95% confidence interval (CI) 27.7-36.2) for 456 household contacts during the omicron variant-dominant period; it was higher than that during the delta variant-dominant period (25.2%) (adjusted risk ratio [aRR] 1.61, CI 1.13-2.28). During the omicron variant-dominant period, HSAR was lower for the household contacts of completely vaccinated index patients (27.3%) than for contacts of other index patients (41.2%) (vaccine effectiveness for infectee 0.43, 95% CI 0.16-0.62) and was significantly higher for female contacts than for male contacts (36.2% vs. 26.1%; aRR 1.29, 95% CI 1.01-1.65). The HSAR was significantly higher during the omicron variant-dominant period than the delta variant-dominant period. The vaccination of index patients might protect household contacts.

A prospective cohort study on the association between waterpipe tobacco smoking and gastric cancer mortality in Northern Vietnam.

Tobacco consumption, as a worldwide problem, is a risk factor for several types of cancer. In Vietnam, tobacco consumption in the form of waterpipe tobacco smoking is common. This prospective cohort study aimed to study the association between waterpipe tobacco smoking and gastric cancer mortality in Northern Vietnam. A total of 25,619 eligible participants were followed up between 2008 and 2019. Waterpipe tobacco and cigarette smoking data were collected; semi-quantitative food frequency and lifestyle questionnaires were also utilized. Gastric cancer mortality was determined via medical records available at the state health facilities. A Cox proportional hazards model was used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI). During 314,992.8 person-years of follow-up, 55 men and 25 women deaths due to gastric cancer were identified. With never-smokers as the reference, the risk of gastric cancer mortality was significantly increased in participants who were ever-smoking (HR = 2.43, 95% CI = 1.35-4.36). The positive risk was also observed in men but was not significantly increased in women. By types of tobacco use, exclusive waterpipe smokers showed a significantly increased risk of gastric cancer mortality (HR = 3.22, 95% CI = 1.67-6.21) but that was not significantly increased in exclusive cigarette smokers (HR = 1.90, 95% CI = 0.88-4.07). There was a significant positive association between tobacco smoking and gastric cancer death for indicators of longer smoking duration, higher frequency per day, and cumulative frequency of both waterpipe and cigarette smoking. Waterpipe tobacco smoking would significantly increase the risk of gastric cancer mortality in the Vietnamese population. Further studies are required to understand the waterpipe tobacco smoking-driven gastric cancer burden and promote necessary interventions.

Time to update the Japanese standard population for comparing mortality rates.

For the last three decades, Japan has been using the population of 1985 for age standardisation to compare mortality rates over time. With the population of Japan declining and ageing rapidly every year, there is a need to update the standard population to make the comparison representative of the current scenario. This is particularly relevant owing to declining mortality rates among the super-ageing Japanese elderly population and more data availability for older age groups. The choice of one population as standard over another is arbitrary because it does not make much difference to the trends in rates. The proportion of elderly in Japan is increasing rapidly and is expected to be one-third of the total population by 2030, in contrast to the proportion of 10% in the 1980s. Using a standard population with a lower proportion of elderly may weight the rates disproportionately for this age group. It is typically suitable to change the standard population every 25 to 30 years. It is advisable to choose the population of 2015 as the new standard population as suggested by the working group of the Ministry of Health, Labour and Welfare of Japan for revising the standard population. However, it should be noted that the newly calculated age-standardised mortality rates will no longer be comparable to those calculated using the older standard populations. Updating the standard population will produce age-standardised rates for recent years closer to the crude rates and would thus reduce the extent of misinterpreting decreased mortality risks using age-standardised rates that do not closely resemble the crude rates.