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.

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 ß-cell function (HOMA-ß) (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-ß (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.

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.

Coffee and green tea consumption with the risk of COVID-19 among the vaccine recipients in Japan: a prospective study.

BACKGROUND: While coffee and green tea have been suggested to have immunoprotective effects, it remains elusive whether they can decrease the risk of COVID-19. OBJECTIVE: We prospectively examined the association between coffee and green tea consumption and the risk of COVID-19 among mRNA vaccine recipients during the epidemic of the Omicron variant. METHOD: Participants were 2,110 staff (aged 18 to 76 years) of a large medical facility in Tokyo, who attended a serosurvey in June 2022, predominatly received ≥3 doses of vaccine, and were followed for COVID-19 until December 2022. Coffee and green tea consumption was ascertained via a questionnaire. COVID-19 was identified through the in-house registry. Cox proportional hazards model was used to estimate the hazard ratios (HRs) of COVID-19 across the categories of beverage consumption. RESULT: During 6 months of follow-up, 225 (10.6%) cases of COVID-19 were identified. Contrary to the expectation, higher consumption of coffee was associated with a significant increase in the risk of COVID-19; multivariable-adjusted HRs (95% CI) was 1.00, 0.92 (0.62-1.35), 1.48 (0.99-2.22), and 1.82 (1.20-2.76) for <1 cup/day, 1 cup/day, 2 cups/day, and ≥3 cups/day, respectively (p trend=0.003). Green tea consumption was not significantly associated with the risk of COVID-19. The association with coffee was attenuated if serologically detected infection was added to the cases. CONCLUSION: In a cohort of Japanese hospital staff who received COVID-19 vaccine, higher consumption of coffee was associated with an increased risk of COVID-19 during the epidemic of the Omicron variant. There was no evidence of a significant association between green tea consumption and COVID-19 risk.

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.

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.

Association of conventional cigarette smoking, heated tobacco product use and dual use with hypertension.

BACKGROUND: Heated tobacco products (HTPs) have emerged as alternatives to conventional cigarettes. However, their health effects remain largely unknown. This study aimed to prospectively explore the association between the use of cigarettes and HTPs and the risk of hypertension. METHODS: This cohort study analysed data from 30 152 workers (82.0% men, mean age 42.9 ± 11.0 years) who were initially free of hypertension, participating in the Japan Epidemiology Collaboration on Occupational Health Study. Participants were categorized into five groups based on their self-reported tobacco product use: never smokers, past smokers, exclusive cigarette smokers, exclusive HTP users and dual users of cigarettes and HTPs. Hypertension cases were identified using three data points from annual health checkup data collected between 2019 and 2021. Cox proportional hazards regression models were used to investigate the association between tobacco product use and hypertension. RESULTS: During a mean follow-up of 2.6 years (range: 0.1-4.0 years), 3656 new cases of hypertension were identified. Compared with never smokers, the risk of hypertension was higher among exclusive cigarette smokers [hazard ratio (HR) 1.26, 95% confidence interval (CI) 1.13-1.41] and exclusive HTP users (HR 1.19, 95% CI 1.06-1.34). There was also a suggestion of increased risk of hypertension among dual users (HR 1.16, 95% CI 0.98-1.38). Furthermore, the risk of hypertension increased with the intensity of cigarette/HTP use in all tobacco product users. CONCLUSIONS: Similarly, both cigarette smoking and HTP use elevate the risk of hypertension. HTPs should not be regarded as less harmful alternatives to traditional cigarettes for preventing hypertension.

Should insulin resistance (HOMA-IR), insulin secretion (HOMA-ß), 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-ß 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-ß; model 4, predictors in model 1 plus FPG, HOMA-IR, and HOMA-ß; 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-ß (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-ß, or replacing BMI with VFA does not significantly improve the model. Further studies are needed to confirm our findings.

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.

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.

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.

Association of conventional cigarette smoking, heated tobacco product use, and dual use with hearing loss: A working population-based study.

INTRODUCTION: Although conventional cigarette smoking has been linked to an increased risk of hearing loss, the association between heated tobacco products (HTPs) and hearing loss is unknown. The objective of this study was to investigate the association between cigarette and HTP use and hearing loss. METHODS: This cross-sectional study examined the data of 7769 employees from five companies (Study I) and 34404 employees from a large company (Study II), all participants in the Japan Epidemiology Collaboration on Occupational Health Study. The participants were categorized into five groups based on their self-reported tobacco use: never smokers, former smokers, exclusive cigarette smokers, exclusive users of HTPs, and those who used both cigarettes and HTPs. Hearing levels were measured using pure-tone audiometry at 1 and 4 kHz frequencies. Separate analyses were carried out for each study, and the results were then combined using fixed-effect models to pool the estimates. RESULTS: The analysis included 42173 participants, with a prevalence of 12.9% for exclusive cigarette smoking, 9.8% for exclusive HTP use, and 5.5% for dual use. The pooled adjusted odds ratios with 95% confidence intervals for unilateral hearing loss at 4 kHz were 1.21 (95% CI: 1.10-1.33) for former smokers, 1.83 (95% CI: 1.64-2.05) for exclusive cigarette smokers,1.46 (95% CI: 1.28-1.67) for exclusive HTP users, and 1.66 (95% CI: 1.41-1.96) for dual users, compared to never smokers. Additionally, the adjusted odds ratios for hearing loss at 4 kHz among exclusive cigarette smokers, exclusive HTP users, and dual users increased with the intensity of cigarette/HTP consumption (all p for trend <0.001). No significant associations were found between exclusive HTP use, dual use, and hearing loss at 1 kHz, apart from exclusive cigarette smoking. CONCLUSIONS: In this cross-sectional study, associations were found between exclusive cigarette smoking, exclusive HTP use, dual use, and hearing loss, particularly at 4 kHz. Further research is needed to confirm these findings.

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.