Age-specific prevalence of IgG against measles/rubella and the impact of routine and supplementary immunization activities: A multistage random cluster sampling study with mathematical modelling

BACKGROUND

Vietnam continues to have measles and rubella outbreaks following supplementary immunization activities (SIA) and routine immunization despite both having high reported coverage. To evaluate immunization activities, age-specific immunity against measles and rubella, and the number of averted Congenital Rubella Syndrome (CRS) cases, must be estimated.

METHODS

Dried blood spots were collected from 2091 randomly selected individuals aged 1-39 years. Measles and rubella virus-specific immunoglobulin G (IgG) were measured by enzyme immunoassay. Results were considered positive at ≥120 mIU/mL for measles and ≥10 IU/mL for rubella. The number of CRS cases averted by immunization since 2014 were estimated using mathematical modelling.

RESULTS

Overall IgG seroprevalence was 99.7% (95%CI: 99.2-99.9) for measles and 83.6% (95%CI: 79.3-87.1) for rubella. Rubella IgG seroprevalence was higher among age groups targeted in the SIA than in non-targeted young adults (95.4% [95%CI: 92.9-97.0] vs 72.4% [95%CI: 63.1-80.1]; P < 0.001). The estimated number of CRS cases averted in 2019 by immunization activities since 2014 ranged from 126 (95%CI: 0-460) to 883 (95%CI: 0-2271) depending on the assumed postvaccination reduction in the force of infection.

CONCLUSIONS

The results suggest the SIA was effective, while young adults born before 1998 who remain unprotected for rubella require further vaccination.

Blood pressure classification using the Japanese Society of Hypertension Guidelines for the Management of Hypertension and cardiovascular events among young to middle-aged working adults

The Japanese Society of Hypertension updated guidelines for hypertension management (JSH2019), changing the blood pressure (BP) classification. However, evidence is sparse regarding the association of the classification with cardiovascular disease (CVD) events among young to middle-aged workers in Japan. We examined this issue using longitudinal data from Japan Epidemiology Collaboration on Occupational Health Study with a prospective cohort design. Participants were 81,876 workers (aged 20-64 years) without taking antihypertensive medication at baseline. BP in 2011 or 2010 was used as exposure. CVD events that occurred from 2012 to 2021 were retrieved from a within-study registry. Cox regression was used to calculate multivariable-adjusted hazard ratios of CVD events. During 0.5 million person-years of follow-up, 334 cardiovascular events, 75 cardiovascular deaths, and 322 all-cause deaths were documented. Compared with normal BP (systolic BP [SBP] < 120 mmHg and diastolic BP [DBP] < 80 mmHg), multivariable-adjusted hazard ratios (95% confidence intervals) of cardiovascular events were 1.98 (1.49-2.65), 2.10 (1.58-2.77), 3.48 (2.33-5.19), 4.12 (2.22-7.64), and 7.81 (3.99-15.30) for high normal BP (SBP120-129 mmHg and DBP < 80 mmHg), elevated BP (SBP130-139 mmHg and/or DBP80-89 mmHg), stage 1 hypertension (SBP140-159 mmHg and DBP90-99 mmHg), stage 2 hypertension (SBP160-179 mmHg and/or DBP100-109 mmHg), and stage 3 hypertension (SBP ≥ 180 mmHg and/or DBP ≥ 110 mmHg), respectively. The highest population attributable fraction was observed in elevated BP (17.8%), followed by stage 1 hypertension (14.1%). The present data suggest that JSH2019 may help identify Japanese workers at a higher cardiovascular risk.

Development and Validation of Prediction Models for the 5-year Risk of Type 2 Diabetes in a Japanese Population: Japan Public Health Center-based Prospective (JPHC) Diabetes Study

BACKGROUND

This study aimed to develop models to predict the 5-year incidence of type 2 diabetes mellitus (T2DM) in a Japanese population and validate them externally in an independent Japanese population.

METHODS

Data from 10,986 participants (aged 46-75 years) in the development cohort of the Japan Public Health Center-based Prospective Diabetes Study and 11,345 participants (aged 46-75 years) in the validation cohort of the Japan Epidemiology Collaboration on Occupational Health Study were used to develop and validate the risk scores in logistic regression models.

RESULTS

We considered non-invasive (sex, body mass index, family history of diabetes mellitus, and diastolic blood pressure) and invasive (glycated hemoglobin [HbA1c] and fasting plasma glucose [FPG]) predictors to predict the 5-year probability of incident diabetes. The area under the receiver operating characteristic curve was 0.643 for the non-invasive risk model, 0.786 for the invasive risk model with HbA1c but not FPG, and 0.845 for the invasive risk model with HbA1c and FPG. The optimism for the performance of all models was small by internal validation. In the internal-external cross-validation, these models tended to show similar discriminative ability across different areas. The discriminative ability of each model was confirmed using external validation datasets. The invasive risk model with only HbA1c was well-calibrated in the validation cohort.

CONCLUSION

Our invasive risk models are expected to discriminate between high- and low-risk individuals with T2DM in a Japanese population.

Association between Fish Intake and Serum Testosterone Levels in Older Males: The Hitachi Health Study II

Background

Fish are rich in omega-3 polyunsaturated fatty acids and vitamin D, which can promote testosterone synthesis and secretion. However, some contaminants present in fish may disrupt testosterone production.

Objective

This study aimed to investigate the association between fish intake (total, fatty, and lean fish) and serum testosterone levels in older males.

Methods

This cross-sectional study included 1545 Japanese males aged 60-69 y who participated in the baseline survey of the Hitachi Health Study II. Fish intake was estimated using a validated brief-type self-administered diet history questionnaire. Total testosterone levels were measured by chemiluminescence immunoassay. Multivariable linear regression analysis was used to analyze the association between fish intake and serum testosterone levels.

Results

Higher total fish intake was associated with higher levels of serum testosterone, with an adjusted mean [95% confidence interval (CI) of 5.63 (5.43, 5.83) and 5.99 (5.78, 6.20)] ng/mL for the 1st and 4th quartiles of total fish intake, respectively (P for trend = 0.06). When analyzing fatty and lean fish separately, higher intake of lean fish, but not fatty fish, was associated with higher levels of serum testosterone: adjusted mean (95% CI): 5.63 (5.43, 5.82) and 6.00 (5.79, 6.20) ng/mL for the 1st and 4th quartiles of lean fish intake, respectively (P for trend = 0.01).

Conclusions

Among older males, higher intake of total fish, particularly lean fish, was associated with higher serum testosterone levels. Curr Dev Nutr 20xx;x:xx.

Vitamin D deficiency during the coronavirus disease 2019 (COVID-19) pandemic among healthcare workers

BACKGROUND & AIMS

Vitamin D deficiency is a common nutritional problem worldwide that may have worsened during the coronavirus disease 2019 (COVID-19) pandemic. The present study sought to examine the prevalence and correlates of vitamin D deficiency among healthcare workers three years after the start of the COVID-19 pandemic.

METHODS

Participants comprised 2543 staff members from a medical research institute, who completed a questionnaire and donated blood samples in June 2023. 25-hydroxyvitamin D (25[OH]D) levels were measured using an electrochemiluminescence immunoassay. Logistic regression was used to calculate the odds ratio and its 95% confidence interval while adjusting for covariates.

RESULTS

The proportions of participants with vitamin D insufficiency (25[OH]D 20-29 ng/mL) and deficiency (25[OH]D < 20 ng/mL) were 44.9% and 45.9%, respectively. In a multivariable-adjusted model, factors associated with a higher prevalence of vitamin D deficiency included younger age, female sex, fewer hours of daytime outdoor physical activity during leisure time (without regular use of sunscreen), lower intake of fatty fish, no use of vitamin D supplements, smoking, and no alcohol consumption. Occupational factors, including shift work, were not independently associated with vitamin D deficiency.

CONCLUSIONS

Our results suggest that vitamin D insufficiency and deficiency are highly prevalent among healthcare workers. Health education regarding lifestyle modifications for this occupational group are warranted to improve their vitamin D status in the COVID-19 era.

Body mass index and lung cancer risk: Pooled analysis of 10 prospective cohort studies in Japan

Mounting evidence suggests that body mass index (BMI) is inversely associated with the risk of lung cancer. However, relatively few studies have explored this association in Asian people, who have a much lower prevalence of obesity than Caucasians. We pooled data from 10 prospective cohort studies involving 444,143 Japanese men and women to address the association between BMI and the risk of lung cancer. Study-specific hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated in each cohort using the Cox proportional hazards model. A meta-analysis was undertaken by combining the results from each cohort. Heterogeneity across studies was evaluated using Cochran's Q and I2statistics. During 5,730,013 person-years of follow-up, 6454 incident lung cancer cases (4727 men and 1727 women) were identified. Baseline BMI was inversely associated with lung cancer risk in men and women combined. While leanness (BMI <18.5) was associated with a higher risk of lung cancer (HR 1.35; 95% CI, 1.16-1.57), overweight and obesity were associated with a lower risk, with HRs of 0.77 (95% CI, 0.71-0.84) and 0.69 (95% CI, 0.45-1.07), respectively. Every 5 kg/m2 increase in BMI was associated with a 21% lower risk of lung cancer (HR 0.79; 95% CI, 0.75-0.83; p < 0.0001). Our pooled analysis indicated that BMI is inversely associated with the risk of lung cancer in the Japanese population. This inverse association could be partly attributed to residual confounding by smoking, as it was more pronounced among male smokers.

Eating behaviors and depressive symptoms among Japanese workers: the Furukawa Nutrition and Health Study

BACKGROUND/OBJECTIVES

In addition to the potential effects of nutrients on mood, eating behaviors have been suggested to be associated with depressive symptoms. We investigated the prospective association between the accumulation of unhealthy eating behaviors and depressive symptoms in a Japanese working population.

METHODS

Participants were 914 workers (aged 19-68 years) who did not have depressive symptoms at baseline (April 2012 and May 2013) and attended a 3-year follow-up survey (April 2015 and May 2016). Unhealthy eating behaviors (skipping breakfast, eating dinner just before bedtime, and snacking after dinner) were assessed at baseline. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression (CES-D) scale at follow-up. Multiple logistic regression was used to estimate the odds ratio of depressive symptoms (CES-D score ≥16) at follow-up according to the number of unhealthy eating behaviors.

RESULTS

In a model with adjustment of background factors, participants having 2-3 unhealthy eating behaviors at baseline had significantly higher risk of developing depressive symptoms (OR, 2.02; 95% CI, 1.21-3.38) compared with those having no such behaviors. After adjustment for occupational and lifestyle factors, the association was slightly attenuated but remained significant (OR, 1.87; 95% CI, 1.10-3.21). This association was further attenuated and became statistically non-significant after additional adjustment for nutritional factors (OR, 1.67; 95% CI, 0.96-2.90).

CONCLUSIONS

Our results suggest that the accumulation of unhealthy eating behaviors is associated with an increased risk of depressive symptoms and that this association may be partly ascribed to a lower intake of nutrients with mood-improving effects.

Comparison of waist circumference and waist-to-height ratio as predictors of clustering of cardiovascular risk factors among middle-aged people in rural Khanh Hoa, Vietnam

OBJECTIVE

Given the population-level variation in stature, a universal cut-off for waist circumference (WC) may not be appropriate for some populations. We compared the performance of WC and waist-to-height ratio (WHtR) to detect the clustering of cardiovascular disease (CVD) risk factors in rural Vietnam.

METHODS

We obtained data from a baseline survey of the Khanh Hoa Cardiovascular Study comprising 2942 middle-aged residents (40-60 years). We used areas under the receiver operating characteristics curve (AUROC), net reclassification index (NRI), and integrated discrimination improvement (IDI) to compare the performance of WC and WHtR in predicting CVD risk clustering (≥2 of the following risk factors: hypertension, diabetes, dyslipidemia, and elevated C-reactive protein).

RESULTS

The optimal cut-off values for WC were 81.8 and 80.7 cm for men and women, respectively. Regarding the clustering of CVD risk factors, the AUROC (95% CI) of WC and WHtR were 0.707 (0.676 to 0.739) and 0.719 (0.689 to 0.749) in men, and 0.682 (0.654 to 0.709) and 0.690 (0.663 to 0.717) in women, respectively. Compared with WC, WHtR had a better NRI (0.229; 0.102-0.344) and IDI (0.012; 0.004-0.020) in men and a better NRI (0.154; 0.050-0.257) in women.

CONCLUSIONS

The optimal WC cut-off for Vietnamese men was approximately 10 cm below the recommended Asian cut-off. WHtR might perform slightly better in predicting the clustering of CVD risk factors among the rural population in Vietnam.

Diabetes, Prediabetes, and the Risk of a Composite Outcome of Long-term Sickness Absence and Pre-retirement Death Due to Physical Disorders

BACKGROUND

Diabetes and prediabetes have been linked with morbidity or mortality from cardiovascular disease, cancer, or other physical disorders among working-age populations, but less is known about outcomes directly related to labor loss (eg, Tlong-term sickness absence [LTSA] or pre-retirement death due to physical disorders).This prospective study aimed to examine the association of diabetes and prediabetes with the risk of a composite outcome of LTSA and pre-retirement death due to physical disorders. The present study also examined the associations of severe outcomes (LTSA or death) due to specific physical disorders or injuries/external causes in relation to diabetes and prediabetes.

METHODS

Data were derived from the Japan Epidemiology Collaboration on Occupational Health study. A total of 60,519 workers from 12 companies were followed for 8 years. Diabetes and prediabetes were defined based on the American Diabetes Association criteria. A Cox proportional hazards regression model was used to examine the association between diabetes/prediabetes and severe outcomes due to physical disorders or injuries/external causes.

RESULTS

The adjusted hazard ratios of severe outcomes due to all physical disorders were 1.22 (95% confidence interval [CI], 1.02-1.45) and 2.32 (95% CI, 2.04-2.64) for prediabetes and diabetes, respectively. In cause-specific analyses, an increased risk was observed for severe outcomes due to cancers, cardiovascular diseases, diseases of the musculoskeletal system, and injuries/external causes in relation to either or both diabetes and prediabetes.

CONCLUSION

Diabetes and prediabetes were associated with an increased risk of severe outcomes due to physical disorders or injuries/external causes among Japanese workers.

Application of deep neural survival networks to the development of risk prediction models for diabetes mellitus, hypertension, and dyslipidemia

OBJECTIVES

: Although numerous risk prediction models have been proposed, few such models have been developed using neural network-based survival analysis. We developed risk prediction models for three cardiovascular disease risk factors (diabetes mellitus, hypertension, and dyslipidemia) among a working-age population in Japan using DeepSurv, a deep feed-forward neural network.

METHODS

: Data were obtained from the Japan Epidemiology Collaboration on Occupational Health Study. A total of 51 258, 44 197, and 31 452 individuals were included in the development of risk models for diabetes mellitus, hypertension, and dyslipidemia, respectively; two-thirds of whom were used to develop prediction models, and the rest were used to validate the models. We compared the performances of DeepSurv-based models with those of prediction models based on the Cox proportional hazards model.

RESULTS

: The area under the receiver-operating characteristic curve was 0.878 [95% confidence interval (CI) = 0.864-0.892] for diabetes mellitus, 0.835 (95% CI = 0.826-0.845) for hypertension, and 0.826 (95% CI = 0.817-0.835) for dyslipidemia. Compared with the Cox proportional hazards-based models, the DeepSurv-based models had better reclassification performance [diabetes mellitus: net reclassification improvement (NRI) = 0.474, P  ≤ 0.001; hypertension: NRI = 0.194, P  ≤ 0.001; dyslipidemia: NRI = 0.397, P  ≤ 0.001] and discrimination performance [diabetes mellitus: integrated discrimination improvement (IDI) = 0.013, P  ≤ 0.001; hypertension: IDI = 0.007, P  ≤ 0.001; and dyslipidemia: IDI = 0.043, P  ≤ 0.001].

CONCLUSION

: This study suggests that DeepSurv has the potential to improve the performance of risk prediction models for cardiovascular disease risk factors.

Association of green tea consumption with prediabetes, diabetes and markers of glucose metabolism in rural Vietnam: a cross-sectional study

The literature on green tea consumption and glucose metabolism has reported conflicting findings. This cross-sectional study examined the association of green tea consumption with abnormal glucose metabolism among 3000 rural residents aged 40-60 years in Khánh Hòa province in Vietnam. Multinomial logistic regression analysis was conducted to examine the association of green tea consumption (0, < 200, 200-< 400, 400-< 600 or ≥ 600 ml/d) with prediabetes and diabetes (based on the American Diabetes Association criteria). Linear regression analysis was performed to examine the association between green tea consumption and the log-transformed homeostatic model assessment of insulin resistance (HOMA-IR) (a marker of insulin resistance) and the log-transformed homeostatic model assessment of β-cell function (HOMA-β) (a marker of insulin secretion). The OR for prediabetes and diabetes among participants who consumed ≥ 600 ml/d v. those who did not consume green tea were 1·61 (95 % CI = 1·07, 2·42) and 2·04 (95 % CI = 1·07, 3·89), respectively. Higher green tea consumption was associated with a higher level of log-transformed HOMA-IR (Pfor trend = 0·04) but not with a lower level of log-transformed HOMA-β (Pfor trend = 0·75). Higher green tea consumption was positively associated with the prevalence of prediabetes, diabetes and insulin resistance in rural Vietnam. The findings of this study indicated prompting the need for further research considering context in understanding the link between green tea consumption and glucose metabolism, especially in rural settings in low- and middle-income countries.

Adult Height and Risk of Colorectal Cancer: A Pooled Analysis of 10 Population-based Cohort Studies in Japan

BACKGROUND

While tall stature has been linked to an increase in the risk of colorectal cancer (CRC), its association with cancer in the colorectum and its subsites remains unclear among Asians.

METHODS

We conducted a pooled analysis of 10 population-based cohort studies among adults in Japan. Each study estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for CRC incidence associated with adult height were estimated using Cox proportional hazards regression with adjustment of the same set of covariates were then pooled to estimate summary HRs incidence using random-effect models.

RESULTS

We identified 9,470 CRC incidences among 390,063 participants during 5,672,930 person-years of follow-up. Men and women with tall stature had a higher risk of CRC and colon cancer. HRs for CRC, colon cancer, and distal colon cancer for the highest versus lowest height categories were 1.23 (95% CI, 1.07-1.40), 1.22 (95% CI, 1.09-1.36), and 1.27 (95% CI, 1.08-1.49), respectively, in men and 1.21 (95% CI, 1.09-1.35), 1.23 (95% CI, 1.08-1.40), and 1.35 (95% CI, 1.003-1.81), respectively, in women. The association with proximal colon cancer and rectal cancer was less evident in both sexes.

CONCLUSION

This pooled analysis confirms the link between tall stature and a higher risk of CRC and colon cancer (especially distal colon) among the Japanese and adds evidence to support the use of adult height to identify those at a higher risk of CRC.

Association between workplace social capital and systolic blood pressure among 23 173 workers at 367 small-sized and medium-sized enterprises in Japan: a cross-sectional study

OBJECTIVES

Social capital (SC) has been shown to be inversely associated with elevated blood pressure. While SC in the workplace may also be associated with blood pressure, it has not been extensively studied. We aimed to investigate the association between workplace SC and systolic blood pressure (SBP).

DESIGN

A cross-sectional study.

SETTING

367 small-sized and medium-sized companies in Japan.

PARTICIPANTS

A total of 23 173 participants (15 991 males and 7182 females) aged ≥18 years.

EXPOSURE OF INTEREST

SC was assessed using individual responses to eight 4-point Likert questions used in the Brief Job Stress Questionnaire. Workplace SC was assessed as the mean of individual-level responses to the SC questions from those working in the same company.

OUTCOME MEASURE

Systolic blood pressure (SBP) RESULTS: A multilevel linear regression model revealed that higher workplace-level SC was linked with lower SBP (coef.=-0.53 per 1SD increment in workplace SC, 95% CI=-1.02 to -0.05) among females in the age-adjusted model, which remained statistically significant after adjusting for other covariates. After adjusting for individual-level SC, this association was attenuated and became non-significant (coef.=-0.41, 95% CI=-0.87 to 0.05), while individual-level SC was inversely associated with SBP (coef.=-0.43, 95% CI=-0.73 to -0.13). Among males, we did not find any evidence of significant inverse associations either in relation to workplace SC (coef.=-0.12, 95% CI=-0.46 to 0.21) or individual-level SC (coef.=0.19, 95% CI=-0.01 to 0.39).

CONCLUSIONS

Our study findings suggested that workplace-level SC can affect SBP differently by sex.

Sex differences in the association between socioeconomic status and untreated hypertension among residents with hypertension in rural Khánh Hòa, Vietnam: a post-hoc analysis

BACKGROUND

Several studies have examined the association between socioeconomic status (SES) and the proportion of untreated hypertension, but have produced conflicting findings. In addition, no study has been conducted to determine sex differences in the association between SES and untreated hypertension. Thus, the aim of this study was to examine whether the associations between SES and the proportion of untreated hypertension differed by sex in Vietnam.

METHODS

This study was conducted using the data of 1189 individuals (558 males and 631 females) who were judged to have hypertension during the baseline survey of a prospective cohort study of 3000 residents aged 40-60 years in the Khánh Hòa Province. A multilevel Poisson regression model with a robust variance estimator was used to examine whether sex and SES indicators (household income and educational attainment) interacted in relation to untreated hypertension.

RESULTS

The proportion of untreated hypertension among individuals identified as hypertensive was 69.1%. We found significant interaction between sex and SES indicators in relation to untreated hypertension (education: p < 0.001; household income: p < 0.001). Specifically, the association between SES and untreated hypertension was inverse among males while it was rather positive among females.

CONCLUSIONS

Our finding suggests that the role of SES in the proportion of untreated hypertension might differ by sex.

Should insulin resistance (HOMA-IR), insulin secretion (HOMA-β), and visceral fat area be considered for improving the performance of diabetes risk prediction models

INTRODUCTION

Insulin resistance and defects in pancreatic beta cells are the two major pathophysiologic abnormalities that underlie type 2 diabetes. In addition, visceral fat area (VFA) is reported to be a stronger predictor for diabetes than body mass index (BMI). Here, we tested whether the performance of diabetes prediction models could be improved by adding HOMA-IR and HOMA-β and replacing BMI with VFA.

RESEARCH DESIGN AND METHODS

We developed five prediction models using data from a cohort study (5578 individuals, of whom 94.7% were male, and 943 had incident diabetes). We conducted a baseline model (model 1) including age, sex, BMI, smoking, dyslipidemia, hypertension, and HbA1c. Subsequently, we developed another four models: model 2, predictors in model 1 plus fasting plasma glucose (FPG); model 3, predictors in model 1 plus HOMA-IR and HOMA-β; model 4, predictors in model 1 plus FPG, HOMA-IR, and HOMA-β; model 5, replaced BMI with VFA in model 2. We assessed model discrimination and calibration for the first 10 years of follow-up.

RESULTS

The addition of FPG to model 1 obviously increased the value of the area under the receiver operating characteristic curve from 0.79 (95% CI 0.78, 0.81) to 0.84 (0.83, 0.85). Compared with model 1, model 2 also significantly improved the risk reclassification and discrimination, with a continuous net reclassification improvement index of 0.61 (0.56, 0.70) and an integrated discrimination improvement index of 0.09 (0.08, 0.10). Adding HOMA-IR and HOMA-β (models 3 and 4) or replacing BMI with VFA (model 5) did not further materially improve the performance.

CONCLUSIONS

This cohort study, primarily composed of male workers, suggests that a model with BMI, FPG, and HbA1c effectively identifies those at high diabetes risk. However, adding HOMA-IR, HOMA-β, or replacing BMI with VFA does not significantly improve the model. Further studies are needed to confirm our findings.

Preinfection Neutralizing Antibodies, Omicron BA.5 Breakthrough Infection, and Long COVID: A Propensity Score-Matched Analysis

BACKGROUND

Data are limited on the role of preinfection humoral immunity protection against Omicron BA.5 infection and long coronavirus disease (COVID) development.

METHODS

We conducted nested case-control analysis among tertiary hospital staff in Tokyo who donated blood samples in June 2022 (1 month before Omicron BA.5 wave), approximately 6 months after receiving a third dose of COVID-19 mRNA vaccine. We measured live virus-neutralizing antibody titers against wild type and Omicron BA.5, and anti-receptor-binding domain (RBD) antibody titers at preinfection, and compared them between cases and propensity-matched controls. Among the breakthrough cases, we examined association between preinfection antibody titers and incidence of long COVID.

RESULTS

Preinfection anti-RBD and neutralizing antibody titers were lower in cases than controls. Neutralizing titers against wild type and Omicron BA.5 were 64% (95% confidence interval [CI], 42%-77%) and 72% (95% CI, 53%-83%) lower, respectively, in cases than controls. Individuals with previous Omicron BA.1/BA.2 infections were more frequent among controls than cases (10.3% vs 0.8%), and their Omicron BA.5 neutralizing titers were 12.8-fold higher than infection-naive individuals. Among cases, preinfection antibody titers were not associated with incidence of long COVID.

CONCLUSIONS

Preinfection immunogenicity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may play a role in protecting against the Omicron BA.5 infection but not preventing long COVID.

Isoflavone intake and depressive symptoms among workers

BACKGROUND & AIM

High intake of isoflavones has been reported to be associated with decreased prevalence of depressive symptoms. However, no prospective study has examined this association. We prospectively investigated the association between isoflavone intake and depressive symptoms in a Japanese working population.

METHODS

Participants were 1162 workers (1033 men and 129 women aged 18-68 years) without depressive symptoms at baseline. Dietary intake was assessed using a validated self-administered diet history questionnaire. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression (CES-D) scale. Cox proportional hazards regression for interval-censored data was used to estimate the hazard ratio of depressive symptoms (CES-D ≥16) according to the tertile of isoflavone intake with adjustment for covariates.

RESULTS

During 5065 person-years of follow-up, 276 (23.8 %) workers were newly identified as having depressive symptoms. Isoflavone intake was not associated with risk of depressive symptoms. After adjustment for lifestyle and dietary factors and baseline CES-D score, the multivariable-adjusted hazard ratios (95 % confidence interval) for the lowest through highest tertile of isoflavone intake were 1.00 (reference), 0.93 (0.66-1.31), and 0.93 (0.62-1.38) (P for trend = 0.70).

CONCLUSIONS

Our findings suggest that higher isoflavone intake is not associated with decreased risk of depressive symptoms among Japanese.

The association between antipyretic analgesics use and SARS-CoV-2 antibody titers following the second dose of the BNT162b2 mRNA vaccine: An observational study

Antipyretic analgesics are used to manage and control symptoms occurring after vaccination, but may hamper immunogenicity or vaccine efficacy. We examined the association between prophylactic or therapeutic use of antipyretic analgesics and SARS-CoV-2 antibody titers for vaccine recipients. Data were obtained from 1,498 staff members of a medical and research institution in Tokyo, Japan, who had received the second dose of the BNT162b2 vaccine. We quantitatively measured anti-SARS-CoV-2 spike protein IgG titers in the participants three months after vaccination. The prophylactic and therapeutic use of antipyretic analgesics was ascertained via a questionnaire. A linear regression model was used to examine the association between antipyretic analgesic use and log-transformed anti-SARS-CoV-2 spike protein IgG titers. Based on model parameters, we estimated geometric mean titers (GMT) and the corresponding 95 % confidence intervals (CI). The results showed that IgG titers in vaccine recipients who used antipyretic analgesics therapeutically was higher than the titers in those who did not (geometric mean ratio [GMR] = 1.26, 95 % CI = 1.17-1.34) with GMTs being 6,147 (95 % CI = 5,833-6,460) and 4,895 (95 % CI = 4,676-5,115) for those who used antipyretic analgesics therapeutically and those who did not, respectively. The association was attenuated, but remained statistically significant after adjusting for symptoms (GMR = 1.14, 95 % CI = 1.06-1.23). We did not find any evidence of significant association in relation to the prophylactic use of antipyretic analgesics (GMR = 0.96, 95 % CI = 0.84-1.10), with GMTs being 5,245 (95 % CI = 4,577-5,913) and 5,452 (95 % CI = 5,258-5,645) for those who used antipyretic analgesics prophylactically and those who did not, respectively. In conclusion, we did not find any evidence of suppression of the humoral response after the second dose of SARS-CoV-2 vaccination by prophylactic or therapeutic use of antipyretic analgesics.

Cigarette Smoking, Smoking Cessation, and Bladder Cancer Risk: A Pooled Analysis of 10 Cohort Studies in Japan

BACKGROUND

Although cigarette smoking is an established risk factor for bladder cancer, assessment of smoking impact on bladder cancer in Asian populations has been hindered by few cohort studies conducted in Asian populations. Therefore, we investigated the risk of bladder cancer associated with smoking status, cumulative smoking intensity, and smoking cessation in Japan.

METHODS

We analyzed data for 157,295 men and 183,202 women in 10 population-based cohort studies in Japan. The risk associated with smoking behaviors was estimated using Cox regression models within each study, and pooled hazard ratios (HRs) and their 95% confidence intervals (CIs) for the incidence of bladder cancer were calculated.

RESULTS

During 4,729,073 person-years of follow-up, 936 men and 325 women developed bladder cancer. In men, former smokers (HR 1.47; 95% CI, 1.18-1.82) and current smokers (HR 1.96; 95% CI, 1.62-2.38) had higher risk than never smokers. In women, current smokers had higher risk than never smokers (HR 2.35; 95% CI, 1.67-3.32). HRs in men linearly increased with increasing pack-years. Risk decreased with increasing years of smoking cessation in men, with a significant dose-response trend. Former smokers with a duration of more than 10 years after smoking cessation had no significantly increased risk compared with never smokers (HR 1.26; 95% CI, 0.97-1.63).

CONCLUSION

Data from a pooled analysis of 10 population-based cohort studies in Japan clearly show an association between cigarette smoking and bladder cancer risk. The risk of smokers may approximate that of never smokers following cessation for many years.

The association between living alone and depressive symptoms and the role of pet ownership among Japanese workers

BACKGROUND

Living alone has been positively associated with the prevalence of depressive symptoms. We examined how a combination of living alone and pet ownership relates to depressive symptoms.

METHODS

As part of the Japan Epidemiology Collaboration on Occupational Health Study, we conducted a survey on health-related lifestyles, including living arrangements and pet ownership, among 12,763 employees of five companies in 2018-2021. Depressive symptoms were assessed using the 11-item Center for Epidemiological Studies-Depression Scale (cutoff score ≥ 9). A Poisson regression model with a robust variance estimator was used to calculate prevalence ratio and 95% confidence interval (CI) while adjusting for covariates.

RESULTS

Among the participants, 30.9% were depressed, 17.7% had pets, and 29.1% lived alone. Compared to individuals living with others but not with a pet, those living alone and not with a pet had a 1.17 times higher prevalence ratio of depressive symptoms (95% CI: 1.08-1.26). The corresponding figures were 1.03 (95% CI: 0.95-1.11) for those living with others and pet(s) and 1.42 (95% CI: 1.18-1.69) for those living alone but with pet(s).

CONCLUSION

Living alone was significantly associated with a higher prevalence of depressive symptoms. The association was rather stronger among individuals with vs. without pets. Pet ownership may not be associated with decreased depressive symptoms.

Durability and determinants of anti-SARS-CoV-2 spike antibodies following the second and third doses of mRNA COVID-19 vaccine

OBJECTIVES

To examine the differences in durability and its determinants of humoral immunity following 2- and 3-dose COVID-19 vaccination.

METHODS

Throughout the pandemic, we evaluated the anti-spike IgG antibody titers of 2- and 3-dose mRNA vaccine recipients over time among the staff of a medical and research center in Tokyo. Linear mixed models were used to estimate trajectories of antibody titers from 14 to 180 days after the last immune-conferred event (vaccination or infection) and compare antibody waning rates across prior infection and vaccination status, and across background factors in infection-naïve participants.

RESULTS

A total of 6901 measurements from 2964 participants (median age, 35 years; 30% male) were analyzed. Antibody waning rate (percentage per 30 days [95% CI]) was slower after 3 doses (25% [23-26]) than 2 doses (36% [35-37]). Participants with hybrid immunity (vaccination and infection) had further slower waning rates: 2-dose plus infection (16% [9-22]); 3-dose plus infection (21% [17-25]). Older age, male sex, obesity, coexisting diseases, immunosuppressant use, smoking, and alcohol drinking were associated with lower antibody titers, whereas these associations disappeared after 3 doses, except for sex (lower in female participants) and immunosuppressant use. Antibody waned slightly faster in older participants, females, and alcohol drinkers after 2 doses, whereas it did not differ after 3 doses across except sex.

DISCUSSION

The 3-dose mRNA vaccine conferred higher durable antibody titers, and previous infection modestly enhanced its durability. The antibody levels at a given time point and waning speed after 2 doses differed across background factors; however, these differences mostly diminished after 3 doses.

The association between experience of COVID-19-related discrimination and psychological distress among healthcare workers for six national medical research centers in Japan

BACKGROUND

Discrimination is an important determinant of negative mental health outcomes. This study determined the association between the experience of COVID-19-related discrimination and psychological distress among healthcare workers (HCWs) in Japan.

METHODS

This cross-sectional study conducted a health survey among 5703 HCWs of six national medical and research centers in Japan from October 2020 to March 2021. COVID-19-related discrimination was defined either when participants or their family members were badmouthed or when they felt discriminated against in some way. We used the Kessler Psychological Distress Scale (K6) to assess the presence of severe psychological distress (≥ 13 points). We used logistic regression models to examine the association between discrimination and psychological distress. We also identified factors associated with discrimination.

RESULTS

Of the participants, 484 (8.4%) reported COVID-19-related discrimination and 486 (8.5%) had severe psychological distress. HCWs who were female vs. male (adjusted odds ratio [AOR] = 1.41, 95% confidence interval [CI] = 1.28-1.55), had high vs. low viral exposure (AOR = 2.31, 95% CI = 1.81-2.93), and worked for 11 or more hours/day vs. 8 or less hours/day (AOR = 1.42, 95% CI = 1.35-1.49) were more likely to have experienced COVID-19-related discrimination. The AOR (95% CI) of severe psychological distress was 1.83 (1.29-2.59) among those who experienced discrimination. In the stratified analysis by sociodemographic and job-related factors, all the interactions did not reach statistical significance (p for interaction > 0.20).

CONCLUSION

Experience of COVID-19-related discrimination was associated with severe psychological distress among HCWs. During the pandemic, effective measures should be taken to prevent the development of negative mental health outcomes in HCWs who experience discrimination.

Development of the Scores for Traditional and Modified Japanese Diets

Increasing attention is being paid to the role of diet quality in the prevention and management of non-communicable diseases. We developed a scoring system for the traditional Japanese diet and its modified version considering the dietary culture in Japan, dietary guidelines for the Japanese, and updated evidence for disease prevention. The traditional Japanese diet comprises white rice, miso soup, soybean products, vegetables, mushrooms, seaweeds, fish and shellfish, high-sodium foods, and green tea. In the modified Japanese diet, unprocessed or minimally refined rice and raw vegetables, milk and dairy products, and fruits were additionally considered, while salty food was reverse-scored. The cutoff for the intake frequency of each food/food group was determined with reference to a health survey of >12,000 workers. Among the participants in the validation study, we confirmed the nutritional gradient with increasing scores in the expected direction. The scores were closely correlated with the respondents' backgrounds, including occupational factors. This simple scoring system can be used for diet quality assessments and epidemiological research.

Cross-Sectional Association between Estimated Hardness of the Habitual Diet and Depressive Symptoms in Older Japanese Men

This cross-sectional study aimed to investigate the association between dietary hardness and depressive symptoms in older Japanese men. Participants were 1487 men aged 60-69 years enrolled in the baseline survey of the Hitachi Health Study II (2017-2020). Habitual dietary intake was estimated by a brief-type, self-administered diet history questionnaire. Dietary hardness was defined as the magnitude of masticatory muscle activity necessary to consume solid foods. The participants who scored ≥ 9 points on a short version of the Center for Epidemiologic Studies Depression Scale were considered to have depressive symptoms. The prevalence of depressive symptoms was 12.7%. The ORs (95% CIs) for depressive symptoms in the third tertile of dietary hardness were significantly lower after adjustment for sociodemographic and lifestyle-related variables and mood-modulating nutrients (ORs [95% CIs]: 0.93 [0.63, 1.36] and 0.58 [0.35, 0.97] for the second and third tertile, respectively [p-value for trend = 0.04]). Dietary hardness was inversely associated with the prevalence of depressive symptoms in older Japanese men. Future studies should confirm these findings and clarify the role of consuming a hard diet in preventing depressive disorders.

Metabolic syndrome and the risk of severe cancer events: a longitudinal study in Japanese workers

BACKGROUND

Metabolic syndrome (MetS) is associated with cancer risk; however, little is known regarding its relationship with the risk of cancer-related premature death and long-term sick leave (LTSL), which can lead to a substantial loss in working years. The present study aimed to quantify the all-site and site-specific associations between MetS and the risk of severe cancer events (a composite outcome of LTSL and mortality due to cancer) in a large working population in Japan.

METHODS

We recruited 70,875 workers (59,950 men and 10,925 women), aged 20-59 years, who attended health check-ups in 2011 (10 companies) and 2014 (2 companies). All workers underwent follow up for severe cancer events until March 31, 2020. MetS was defined in accordance with the Joint Interim Statement. Cox regression models were used to quantify the association between baseline MetS and severe cancer events.

RESULTS

During 427,379 person-years of follow-up, 523 participants experienced the outcome consisting of 493 LTSLs of which 124 eventually resulted in death, and 30 deaths without taking LTSL. The adjusted hazard ratios (HR) (95% confidence intervals [CI]) for composite severe events due to all-site, obesity-related, and non-obesity-related cancer among those with vs. without MetS were 1.26 (1.03, 1.55), 1.37 (1.04, 1.82), and 1.15 (0.84, 1.56), respectively. In cancer site-specific analyses, MetS was associated with an increased risk of severe events due to pancreatic cancer (HR, 2.06; 95% CI, 0.99-4.26). When mortality was treated solely as the endpoint, the association was significant for all-site (HR, 1.58; 95% CI, 1.10-2.26), and obesity-related (HR, 1.59; 95% CI, 1.00-2.54) cancer. Additionally, a greater number of MetS components was associated with a greater risk of both severe cancer events and cancer-related mortality (P trend < 0.05).

CONCLUSION

Among Japanese workers, MetS was associated with an increased risk of severe cancer events, especially those due to obesity-linked cancer.

Association between Dietary Hardness and Cognitive Dysfunction among Japanese Men in Their 60s: A Cross-Sectional Study

We aimed to examine the cross-sectional association between dietary hardness and cognitive dysfunction among Japanese men in their 60s. Participants were 1494 men aged 60-69 years from the baseline survey of Hitachi Health Study II (2017-2020). Dietary hardness was defined as an estimate of masticatory muscle activity involved in consuming solid foods. Habitual intake of these foods was assessed using a brief-type, self-administered diet history questionnaire. Cognitive dysfunction was defined as a score ≤ 13 points on the test battery for screening for Alzheimer's disease (MSP-1100). The mean (SD) age of participants was 63.5 (3.5) years. The prevalence of cognitive dysfunction was 7.5%. The ORs (95% CIs) for cognitive dysfunction in the second and third tertiles were: 0.77 (0.47, 1.26) and 0.87 (0.54, 1.41), respectively, after adjustment for socio-demographic factors (p for trend = 0.73). After further adjustment for protective nutrient intake against cognitive dysfunction, the corresponding figures were 0.72 (0.43, 1.21) and 0.79 (0.43, 1.46), respectively (p for trend = 0.57). Dietary hardness was not associated with the prevalence of cognitive dysfunction among Japanese men in their 60s. Future prospective studies are necessary to investigate the association between dietary hardness estimated by a validated questionnaire and cognitive dysfunctions.

Omicron BA.1 neutralizing antibody response following Delta breakthrough infection compared with booster vaccination of BNT162b2

BACKGROUND

Longitudinal data are lacking to compare booster effects of Delta breakthrough infection versus third vaccine dose on neutralizing antibodies (NAb) against Omicron.

METHODS

Participants were the staff of a national research and medical institution in Tokyo who attended serological surveys on June 2021 (baseline) and December 2021 (follow-up); in between, the Delta-dominant epidemic occurred. Of 844 participants who were infection-naïve and had received two doses of BNT162b2 at baseline, we identified 11 breakthrough infections during follow-up. One control matched to each case was selected from boosted and unboosted individuals. We compared live-virus NAb against Wild-type, Delta, and Omicron BA.1 across groups.

RESULTS

Breakthrough infection cases showed marked increases in NAb titers against Wild-type (4.1-fold) and Delta (5.5-fold), and 64% had detectable NAb against Omicron BA.1 at follow-up, although the NAb against Omicron after breakthrough infection was 6.7- and 5.2-fold lower than Wild-type and Delta, respectively. The increase was apparent only in symptomatic cases and as high as in the third vaccine recipients.

CONCLUSIONS

Symptomatic Delta breakthrough infection increased NAb against Wild-type, Delta, and Omicron BA.1, similar to the third vaccine. Given the much lower NAb against Omicron BA.1, infection prevention measures must be continued irrespective of vaccine and infection history while the immune evasive variants are circulating.

Red meat consumption is associated with prediabetes and diabetes in rural Vietnam: a cross-sectional study

OBJECTIVE

To examine the association between red/processed meat consumption and glycaemic conditions (i.e. prediabetes (preDM) and diabetes mellitus (DM)) among middle-aged residents in rural Khánh Hòa, Vietnam.

DESIGN

In this cross-sectional study, a multinomial logistic regression model was used to examine the association between daily consumption of red/processed meat (0-99 g, 100-199 g or ≥ 200 g) and preDM/DM with adjustments for socio-demographic, lifestyle-related and health-related variables.

SETTING

Khánh Hòa Province, Vietnam.

PARTICIPANTS

The study used data collected through a baseline survey conducted during a prospective cohort study on CVD among 3000 residents, aged 40-60 years, living in rural communes in Khánh Hòa Province.

RESULTS

The multinomial regression model revealed that the relative-risk ratios for DM were 1·00 (reference), 1·11 (95 % CI = 0·75, 1·62) and 1·80 (95 % CI = 1·40, 2·32) from the lowest to the highest red/processed meat consumption categories (Ptrend = 0·006). The corresponding values for preDM were 1·00 (reference), 1·25 (95 % CI = 1·01, 1·54) and 1·67 (95 % CI = 1·20, 2·33) (Ptrend = 0·004). We did not find any evidence of statistical significance in relation to poultry consumption.

CONCLUSION

Increased red/processed meat consumption, but not poultry consumption, was positively associated with the prevalence of preDM/DM in rural communes in Khánh Hòa Province, Vietnam. Dietary recommendations involving a reduction in red/processed meat consumption should be considered in low- and middle-income countries.

Different associations of occupational and leisure-time physical activity with the prevalence of hypertension among middle-aged community dwellers in rural Khánh Hòa, Vietnam

BACKGROUND

In contrast to high-income countries where physical activity (PA), particularly leisure-time PA, has been shown to be protective against hypertension, few studies have been conducted in low- and middle-income countries. We examined the cross-sectional association between PA and hypertension prevalence among rural residents in Vietnam.

METHODS

We used data collected in the baseline survey of a prospective cohort study, among 3000 people aged 40-60 years old residing in rural Khánh Hòa, Vietnam. Hypertension was defined as systolic blood pressure ≥ 140 mmHg, diastolic blood pressure ≥ 90 mmHg, or the use of antihypertensive medication. We assessed occupational PA and leisure-time PA using the Global Physical Activity Questionnaire. A robust Poisson regression model was used to investigate the associations, with adjustment for covariates.

RESULTS

The prevalence of hypertension was 39.6%. After adjusting for socio-demographic and lifestyle-related variables, leisure-time PA was positively associated with hypertension prevalence (prevalence ratio [PR]: 1.03 per 10 MET-hour/week, 95% confidence interval [CI] 1.01-1.06). Occupational PA was inversely associated with hypertension prevalence (PR: 0.98 per 50 MET-hour/week, 95% CI = 0.96-0.996). After adjusting for BMI and other health-related variables, the association related to occupational PA became statistically non-significant, while the association related to leisure-time PA remained statistically significant.

CONCLUSION

In contrast to previous studies in high-income countries, we found that leisure-time PA was positively associated with hypertension prevalence and occupational PA was associated with a lower hypertension prevalence. This suggests that the association between PA and hypertension might differ depending on the context.

Body mass index and esophageal and gastric cancer: a pooled analysis of ten population-based cohort studies in Japan

The effect of body mass index (BMI) on esophageal and gastric carcinogenesis might be heterogeneous, depending on subtype or subsite. However, findings from prospective evaluations of BMI associated with these cancers among Asian populations have been inconsistent and limited, especially for esophageal adenocarcinoma and gastric cardia cancer. We performed a pooled analysis of ten population-based cohort studies to examine this association in 394,247 Japanese individuals. We used Cox proportional hazards regression to estimate study-specific hazard ratios (HRs) and 95% confidence intervals (CIs), then pooled these estimates to calculate summary HRs with a random effects model. During 5,750,107 person-years of follow-up, 1,569 esophageal cancer (1,038 squamous cell carcinoma and 86 adenocarcinoma) and 11,095 gastric (728 cardia and 5,620 non-cardia) cancer incident cases were identified. An inverse association was observed between BMI and esophageal squamous cell carcinoma (HR per 5-kg/m² increase, 0.57; 95% CI, 0.50-0.65), whereas a positive association was seen in gastric cardia cancer (HR, 1.15; 95% CI, 1.00-1.32). A non-significant and significant positive association for overweight or obese (BMI ≥25 kg/m² ) relative to BMI <25 kg/m² was observed with esophageal adenocarcinoma (HR, 1.32; 95% CI, 0.80-2.17) and gastric cardia cancer (HR, 1.24; 95% CI, 1.05-1.46), respectively. No clear association with BMI was found for gastric non-cardia cancer. This prospective study - the largest in an Asian country - provides a comprehensive quantitative estimate of the association of BMI with upper gastrointestinal cancer, and confirms the subtype- or subsite-specific carcinogenic impact of BMI in a Japanese population.

Cumulative and undiagnosed SARS-CoV-2 infection among the staff of a medical research centre in Tokyo after the emergence of variants

To describe the trend of cumulative incidence of coronavirus disease 19 (COVID-19) and undiagnosed cases over the pandemic through the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants among healthcare workers in Tokyo, we analysed data of repeated serological surveys and in-house COVID-19 registry among the staff of National Center for Global Health and Medicine. Participants were asked to donate venous blood and complete a survey questionnaire about COVID-19 diagnosis and vaccine. Positive serology was defined as being positive on Roche or Abbott assay against SARS-CoV-2 nucleocapsid protein, and cumulative infection was defined as either being seropositive or having a history of COVID-19. Cumulative infection has increased from 2.0% in June 2021 (pre-Delta) to 5.3% in December 2021 (post-Delta). After the emergence of the Omicron, it has increased substantially during 2022 (16.9% in June and 39.0% in December). As of December 2022, 30% of those who were infected in the past were not aware of their infection. Results indicate that SARS-CoV-2 infection has rapidly expanded during the Omicron-variant epidemic among healthcare workers in Tokyo and that a sizable number of infections were undiagnosed.

Eating speed and abdominal adiposity in middle-aged adults: a cross-sectional study in Vietnam

BACKGROUND

Several studies have associated fast eating speed with the risk of general obesity, but there are inadequate data on the association between eating speed and abdominal adiposity which may pose a higher threat to health than general obesity. The present study aimed to investigate the association between eating speed and abdominal obesity in a Vietnamese population.

METHODS

Between June 2019 and June 2020, the baseline survey of an ongoing prospective cohort study on the determinants of cardiovascular disease in Vietnamese adults was conducted. A total of 3,000 people aged 40-60 years old (1,160 men and 1,840 women) were recruited from eight communes in the rural district of Cam Lam, Khanh Hoa province, in Central Vietnam. Self-reported eating speed was assessed on a 5-point Likert scale, and responses were collapsed into the following three categories: slow, normal, and fast. Abdominal obesity was defined as a waist-to-height ratio of ≥ 0.5. Poisson regression with a robust variance estimator was used to assess the association between eating speed and abdominal obesity.

RESULTS

Compared with slow eating speed, the adjusted prevalence ratio (95% confidence interval) for abdominal obesity was 1.14 (1.05, 1.25)1.14 (1.05, 1.25) for normal eating speed and 1.30 (1.19, 1.41) for fast eating speed (P for trend < 0.001).

CONCLUSION

A faster eating speed was associated with a higher prevalence of abdominal obesity in a middle-aged population in rural Vietnam.

Heated tobacco product use and abnormal glucose metabolism: a working population-based study

AIMS

We aimed to assess the cross-sectional association of heated tobacco product (HTP) use with prediabetes and diabetes.

METHODS

The present analysis included 8950 workers from 5 companies (Study I) and 31,341 workers from another large company (Study II), who participated in the Japan Epidemiology Collaboration on Occupational Health Study. The participants were divided into five groups: never smokers, past smokers, exclusive HTP users, dual users of cigarettes and HTPs, and exclusive cigarette smokers. Diabetes and prediabetes were defined according to the fasting blood glucose and HbA1c levels and self-reported diabetes treatment, using the American Diabetes Association criteria. We analyzed the data of Study I and II separately, and then pooled these estimates using the fixed-effect models, with adjustment for a wide range of covariates.

RESULTS

In this study that included 40,291 participants (mean age, 46.6 years; men, 84.3%), about half of the current tobacco-related product users reported using HTPs. Exclusive HTP users had higher odds of prediabetes (pooled odds ratio 1.36; 95% CI 1.25-1.47) and diabetes (1.68; 95% CI 1.45-1.94) than never smokers. Similarly, dual users also had increased odds of prediabetes (pooled odds ratio, 1.26; 95% CI 1.13-1.39) and diabetes (1.93; 95% CI 1.63-2.29). The strength of these associations was comparable to that of cigarette smokers. We observed significantly higher HbA1c and fasting blood glucose levels among both exclusive HTP users and dual users compared to never smokers.

CONCLUSION

HTP use was associated with an increased likelihood of prediabetes and diabetes. Prospective studies are warranted to confirm the cross-sectional association.

Dyslipidemia and SARS-CoV-2 spike antibody titres after the second and third doses of the BNT162b2 vaccine among healthcare workers in Japan

OBJECTIVE

This study aimed to examine the sex-associated differences in the relationship between dyslipidemia and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike immunoglobulin (Ig)G antibodies among BNT162b2 vaccine recipients.

METHODS

Participants were staff members (aged 21-75 years) of a medical and research institution who underwent an anti-SARS-CoV-2 spike IgG antibody test after the second (n = 1872) and third doses (n = 1075) of the BNT162b2 vaccine. Dyslipidemia was defined as triglyceride level ≥150 mg/dl, high-density lipoprotein-cholesterol level <40 mg/dl, low-density lipoprotein-cholesterol level ≥140 mg/dl, or lipid-lowering medication use. Multivariable linear regression was used to calculate the ratio of means for SARS-CoV-2 spike IgG titre according to dyslipidemia status.

RESULTS

The prevalence of dyslipidemia was 38.0% in men and 19.6% in women. The relationship between dyslipidemia and SARS-CoV-2 spike IgG titres after the second dose differed markedly by sex (P for interaction <0.001). In men, dyslipidemia was associated with significantly lower IgG titres: the ratio of means (95% confidence interval) was 0.82 (0.72-0.93). However, this association disappeared after the third dose (0.96 [0.78-1.18]). Of the dyslipidemia components, hypertriglyceridemia was inversely associated with SARS-CoV-2 spike IgG antibody titre after both the second and third doses (ratio of means: 0.82 [0.70-0.95] and 0.73 [0.56-0.95], respectively). In women, IgG titres did not differ according to dyslipidemia or hypertriglyceridemia status after either dose.

CONCLUSIONS

These results suggest a detrimental role of hypertriglyceridemia in the humoral immune response to the BNT162b2 vaccine for COVID-19 in men but not in women.

Vitamin D intake and all-cause and cause-specific mortality in Japanese men and women: the Japan Public Health Center-based prospective study

While higher circulating 25-hydroxyvitamin D concentrations have been reported to be associated with decreased risk of all-cause mortality, evidence on dietary vitamin D intake is limited and inconsistent. We investigated whether vitamin D intake is associated with all-cause and cause-specific mortality among Japanese adults. Participants were 42,992 men and 50,693 women who responded to the second survey of the Japan Public Health Center-based Prospective Study (1995-1998) and who were followed up for mortality through 2018. Dietary intake was ascertained using a validated food frequency questionnaire. Hazard ratios of deaths from the second survey to December 2018 were estimated using Cox proportional hazard regression analysis. During follow-up, we identified 22,630 deaths. Overall, the third and fourth quintiles, but not the highest quintile, of vitamin D intake were each associated with a significantly lower risk of all-cause mortality. In subgroups characterized by low sunlight exposure, risk of all-cause mortality decreased linearly with increasing vitamin D intake. The multivariable-adjusted hazard ratios (95% confidence intervals) of all-cause mortality for the highest versus lowest quintile of vitamin D intake were 0.87 (0.79-0.95) in women and 0.88 (0.79-0.97) in residents of higher latitude areas. Lower risk was also observed for all-cause mortality in participants with hypertension and for heart disease mortality in those with higher calcium intake. Higher vitamin D intake was associated with decreased risk of ischemic stroke and pneumonia mortality. Higher dietary vitamin D was associated with a lower risk of mortality among individuals with low sunlight exposure or hypertension. Individuals with potentially low vitamin D may benefit from increasing dietary vitamin D intake for the prevention of premature death.

Parental absence during childhood and weight status in adulthood among middle-aged community dwellers in rural Vietnam

OBJECTIVES

While adverse childhood experiences (ACEs) have been shown to be associated with adulthood obesity, less is known about their association with underweight. We examined the associations between parental absence (i.e., a major component of ACEs) and both underweight and excess weight among middle-aged rural community dwellers in Vietnam, where experiences of parental absence was not uncommon during and after the Vietnam War (1955-1975).

METHODS

Data came from 3000 middle-aged adults who participated in the baseline survey of Khánh Hòa Cardiovascular Study. Parental absence was defined as parental absence due to death, divorce, or out-migration. Using information on the timing of such events, we categorized participants into those who experienced parental absence before the age of 3, between the ages of 3 and 15, and those without such experiences. BMI was calculated based on measured height and weight (kg/m² ) and categorized into three groups: underweight <18.5; normal 18.5-24.9; excess weight ≥ 25. Multinomial logistic regression was then used to investigate the association between parental absence and adult weight status.

RESULTS

Parental absence that occurred before the age of 3 was marginally significantly associated with underweight (relative risk ratio [RRR] = 1.44, 95% confidence interval [CI] 0.95, 2.20) but not with overweight/obesity. Parental divorce was associated with overweight/obesity (RRR = 2.48, 95% CI 1.28, 4.81), but not parental absence due to migratory work.

CONCLUSIONS

While previous studies in Western settings focused almost exclusively on the risk of obesity in relation to exposure to ACEs, our findings point to the potential importance of considering the risk of underweight in low- and middle-income countries.

Neutralizing antibodies after three doses of the BNT162b2 vaccine, breakthrough infection, and symptoms during the Omicron-predominant wave

OBJECTIVES

To investigate the role of immunogenicity after the third vaccine dose against Omicron infection and COVID-19-compatible symptoms of infection.

METHODS

First, we examined vaccine effectiveness (VE) of the third dose against the second dose during the Omicron wave among the staff at a tertiary hospital in Tokyo. In a case-control study of third vaccine recipients, we compared the preinfection live-virus neutralizing antibodies (NAb) against Omicron between breakthrough cases and their controls who had close contact with patients with COVID-19. Among these cases, we examined the association between NAb levels and the number of COVID-19-compatible symptoms.

RESULTS

Among the 1456 participants for VE analysis, 60 breakthrough infections occurred during the Omicron wave. The third dose VE for infection was 54.6%. Among the third dose recipients, NAb levels against Omicron did not differ between the cases (n = 22) and controls (n = 21). Among the cases, those who experienced COVID-19-compatible symptoms had lower NAb levels against Omicron than those who did not.

CONCLUSION

The third vaccine dose was effective in decreasing the risk of SARS-CoV-2 infection during Omicron wave compared with the second dose. Among third dose recipients, higher preinfection NAb levels may not be associated with a lower risk of Omicron infection. Contrarily, they may be associated with fewer symptoms of infection.

Analysis of Previous Infection, Vaccinations, and Anti-SARS-CoV-2 Antibody Titers and Protection Against Infection With the SARS-CoV-2 Omicron BA.5 Variant

This cohort study examines whether preinfection anti–SARS-CoV-2 spike antibody titer is associated with protection against Omicron BA.5 infection among staff members of a medical and research center in Tokyo, Japan.

Prevalence of family history of cancer in the NC-CCAPH consortium of Japan

The objective of this study was to identify the prevalence of family history of cancer using cohorts participating in the Japanese National Center Cohort Collaborative for Advancing Population Health (NC-CCAPH). We pooled data from seven eligible cohorts of the Collaborative with available data on family history of cancer. Prevalence of family history of cancer and corresponding 95% confidence intervals are presented for all cancers and selected site-specific cancers for the total population and stratified by sex, age, and birth cohort. Prevalence of family history of cancer increased with age ranging from 10.51% in the 15 to 39 year age category to 47.11% in 70-year-olds. Overall prevalence increased in birth cohorts from ≤ 1929 until 1960 and decreased for the next two decades. Gastric cancer (11.97%) was the most common site recorded for family members, followed by colorectal and lung (5.75%), prostate (4.37%), breast (3.43%) and liver (3.05%) cancer. Women consistently had a higher prevalence of family history of cancer (34.32%) versus men (28.75%). Almost one in three participants had a family history of cancer in this Japanese consortium study highlighting the importance of early and targeted cancer screening services.

Comparison of risk factors for SARS-CoV-2 infection among healthcare workers during Omicron and Delta dominance periods in Japan

BACKGROUND

The risk factors for coronavirus disease (COVID-19) among healthcare workers (HCWs) might have changed since the emergence of the highly immune evasive Omicron variant.

AIM

To compare the risk factors for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among HCWs during the Delta- and Omicron-predominant periods.

METHODS

Using data from repeated serosurveys among the staff of a medical research centre in Tokyo, two cohorts were established: Delta period cohort (N = 858) and Omicron period cohort (N = 652). The potential risk factors were assessed using a questionnaire. Acute/current or past SARS-CoV-2 infection was identified by polymerase chain reaction or anti-nucleocapsid antibody tests, respectively. Poisson regression was used to calculate the risk ratio (RR) of infection risk.

FINDINGS

The risk of SARS-CoV-2 infection during the early Omicron-predominant period was 3.4-fold higher than during the Delta-predominant period. Neither working in a COVID-19-related department nor having a higher degree of occupational exposure to SARS-CoV-2 was associated with an increased infection risk during both periods. During the Omicron-predominant period, infection risk was higher among those who spent ≥30 min in closed spaces, crowded spaces, and close-contact settings without wearing mask (≥3 times versus never: RR: 6.62; 95% confidence interval: 3.01-14.58), whereas no such association was found during the Delta period.

CONCLUSION

Occupational exposure to COVID-19-related work was not associated with the risk of SARS-CoV-2 infection in the Delta or Omicron period, whereas high-risk behaviours were associated with an increased infection risk during the Omicron period.

COVID-19-related discrimination, PTSD symptoms, and psychological distress in healthcare workers

To date, little effort has been made to examine if frontline workers who deal with COVID-19 patients are more likely to experience discrimination than second-line workers. Also, little information has appeared on how COVID-19-related discrimination affects PTSD symptoms in healthcare workers. We aimed to examine the association between COVID-19-related discrimination and frontline worker status. We further aimed to examine how COVID-19-related discrimination was associated with PTSD symptoms and psychological distress. We studied 647 healthcare workers. For the association between COVID-19-related discrimination and frontline worker status, we conducted multivariable logistic regression adjusting for age, sex and living alone. For the association of COVID-19-related discrimination with PTSD symptoms and psychological distress, we performed multivariable regression using hierarchical adjustments for age, sex, living alone, alcohol consumption, exercise and frontline worker status. Bias-corrected and accelerated bootstrap confidence intervals (CIs) were used. A total of 136 individuals worked on the frontline and the largest group were nurses (n = 81, 59.6%). Frontline workers had increased odds of COVID-19-related discrimination compared with second-line workers (odds ratio = 2.60, 95% CI = 1.37-4.96). COVID-19-related discrimination was associated with PTSD symptoms and psychological distress even at the highest level of adjustment (β = 0.67, 95% CI = 0.10-1.23; β = 2.43, 95% CI = 0.91-3.95, respectively). Frontline workers are more likely to experience COVID-19-related discrimination than second-line workers. Such discrimination may result in PTSD symptoms and psychological distress. Interventions to prevent COVID-19-related discrimination against healthcare workers, for example anti-discrimination campaigns, are important.

Underlying medical conditions and anti-SARS-CoV-2 spike IgG antibody titers after two doses of BNT162b2 vaccination: A cross-sectional study

Patients with underlying medical conditions are at high risk of developing serious symptoms of the coronavirus disease 2019 than healthy individuals; therefore, it is necessary to evaluate the immune response to vaccination among them to formulate precision and personalized vaccination strategies. However, inconsistent evidence exists regarding whether patients with underlying medical conditions have lower anti-SARS-CoV-2 spike IgG antibody titers. We performed a cross-sectional study enrolling 2762 healthcare workers who received second doses of BNT162b2 vaccination from three medical and research institutes between June and July, 2021. Medical conditions were surveyed by a questionnaire, and spike IgG antibody titers were measured with chemiluminescent enzyme immunoassay using serum collected on the median of 62 days after the second vaccination. Multilevel linear regression model was used to estimate geometric mean and ratio of mean (95% confidence interval, CI) for the presence and absence of medical conditions and treatments. Among all participants (median age, 40 years [interquartile range, 30-50]; male proportion, 29.4%), the prevalence of hypertension, diabetes, chronic lung disease, cardiovascular disease, and cancer was 7.5%, 2.3%, 3.8%, 1.8%, and 1.3%, respectively. Patients with treated hypertension had lower antibody titers than those without hypertension; the multivariable-adjusted ratio of mean (95% CI) was 0.86 (0.76-0.98). Patients with untreated and treated diabetes had lower antibody titers than those without diabetes; the multivariable-adjusted ratio of mean (95% CI) was 0.63 (0.42-0.95) and 0.77 (0.63-0.95), respectively. No substantial difference was observed between the presence or absence of chronic lung disease, cardiovascular disease, or cancer. Patients with untreated hypertension and patients with untreated and treated diabetes had lower spike IgG antibody titers than participants without those medical conditions, suggesting that continuous monitoring of antibody titers and further booster shots could be necessary to maintain adaptive immunity in patients with hypertension or diabetes.

Association between parental absence during childhood and metabolic syndrome during adulthood: A cross-sectional study in rural Khanh Hoa, Vietnam

BACKGROUND

This study aimed to determine the association between parental absence during childhood and metabolic syndrome (MetS) in adulthood among middle-aged adults in rural Khanh Hoa province, Vietnam. Given that broader literature on adverse childhood experiences (ACEs) suggests a strong positive association between ACEs and cardiometabolic risk or diseases, we hypothesized that parental absence during childhood, which is a major component of ACEs, is more likely to cause MetS in adulthood.

METHODS

Data were obtained from the baseline survey of the Khanh Hoa Cardiovascular Study, in which 3000 residents aged between 40 to 60 years participated. MetS was assessed using the modified Adult Treatment Panel III (ATP III) criteria. It was considered parental absence if the participants had experienced parental absence due to death, divorce, or out-migration before three or between three to 15 years. We used multiple logistic regression analyses to examine the association between parental absence during childhood and metabolic syndrome during adulthood.

RESULTS

There was no significant association between parental absence and MetS; adjusted odds ratio [AOR] was 0.97 (95% confidence interval [CI] = 0.76-1.22) for those who experienced parental absence between three to 15 years and the corresponding figure for those who experienced it before three years was 0.93 (95% CI = 0.72-1.20). No significant associations were observed when these were examined for the causes of parental absence.

CONCLUSION

This study did not support our hypothesis of an association between parental absence during childhood and metabolic syndrome during adulthood. Parental absence may not be a predictor of MetS among Vietnamese people in rural communities.

Impact of hepatitis B vaccination programs in Vietnam evaluated by estimating HBsAg prevalence

Background

Vietnam introduced a 3-dose hepatitis B (HBV) immunization program comprising 1 dose immediately after birth and 2 or 3 in infancy in the past 20 years, but the impact of the vaccine has not been systematically evaluated. Thus, we conducted this survey aiming to estimate the age-specific chronic HBV prevalence in the general population and to evaluate HBV immunization effectiveness.

Methods

Population-based, four-stage cluster sampling was used in the South Central Coast region of Vietnam. The point-of-care Determine rapid test was used to assess hepatitis B surface antigen (HBsAg) positivity.

Results

A total of 2,075 samples were included in the study. HBsAg prevalence was significantly higher among adults aged 20-39 years than in the population aged 1-19 years (8.0% [95% confidence interval 5.0-12.0] vs. 2.0% [95% confidence interval 1.0-6.0], p<0.01). HBsAg prevalence decreased after implementation of the 3-dose vaccination schedule during infancy from 1997 to 2002, whereas the change in prevalence after implementation of the birth dosing was not significant. A slight increase in HBsAg prevalence was observed for the cohort born in 2011, 2012, and 2013, when there was a vaccine shortage and media reports of immunization resistance.

Conclusions

This is the first population-based assessment of the introduction of the HBV vaccine in Vietnam performed by estimating the HBsAg prevalence across a wide range of ages. The results showed that the HBV immunization policy effectively reduces HBsAg prevalence in general, although birth dosing of the vaccine and low immunization coverage should be carefully monitored.

Individual-level social capital is associated with depressive symptoms among middle-aged community dwellers in rural Vietnam: a cross-sectional study

OBJECTIVES

There has been comparatively little research on the association between social capital and depressive symptoms in low- and middle-income countries. To address this deficit this study examined the association among middle-aged adults in rural Vietnam.

DESIGN

A cross-sectional study.

SETTING

Data came from the baseline survey of the Khánh Hòa Cardiovascular Study, which is an ongoing prospective cohort study aiming to elucidate the determinants of cardiovascular diseases.

PARTICIPANTS

A total of 3000 people aged 40-60 years old residing in rural communes in Khánh Hòa province, Vietnam.

EXPOSURE OF INTEREST

Cognitive social capital (ie, low, middle and high) and structural social capital (in terms of social participation; yes or no) were assessed via a questionnaire.

PRIMARY OUTCOME MEASURE

Depressive symptoms were assessed with the 11-item Center for Epidemiologic Studies Depression Scale.

RESULTS

A robust Poisson regression model revealed that adults in the highest versus lowest cognitive social capital tertile had a 61% lower prevalence of depressive symptoms (prevalence ratio (PR)=0.39, 95% CI=0.31 to 0.49). Individuals with higher structural social capital were also significantly less likely to experience depressive symptoms (PR=0.74, 95% CI=0.61 to 0.90).

CONCLUSION

In a cohort of 3000 middle-aged rural residents in Vietnam, both cognitive and structural social capital assessed at the individual level were inversely associated with the prevalence of depressive symptoms.