Association of metabolites of benzene and toluene with lipid profiles in Korean adults: Korean National Environmental Health Survey (2015-2017).

BACKGROUND: Environmental exposure to benzene and toluene is a suspected risk factor for metabolic disorders among the general adult population. However, the effects of benzene and toluene on blood lipid profiles remain unclear. In this study, we investigated the association between urinary blood lipid profiles and metabolites of benzene and toluene in Korean adults. METHODS: We analyzed the data of 3,423 adults from the Korean National Environmental Health Survey Cycle 3 (2015-2017). We used urinary trans,trans-muconic acid (ttMA) as a biomarker of benzene exposure, and urinary benzylmercapturic acid (BMA) as an indicator of toluene exposure. Multivariate logistic regression analyses were performed to explore the association between blood lipid profiles and urinary metabolites of benzene and toluene. Additionally, we examined the linear relationship and urinary metabolites of benzene and toluene between lipoprotein ratios using multivariate regression analyses. RESULTS: After adjusting for covariates, the fourth quartile (Q4) of ttMA [odds ratio (OR) (95% confidence interval, CI = 1.599 (1.231, 2.077)] and Q3 of BMA [OR (95% CI) = 1.579 (1.129, 2.208)] were associated with an increased risk of hypertriglyceridemia. However, the Q4 of urinary ttMA [OR (95% CI) = 0.654 (0.446, 0.961)] and Q3 of urinary BMA [OR (95% CI) = 0.619 (0.430, 0.889)] decreased the risk of a high level of low-density lipoprotein cholesterol (LDL-C). Higher urinary ttMA levels were positively associated with the ratio of triglycerides to high-density lipoproteins [Q4 compared to Q1: ß = 0.11, 95% CI: (0.02, 0.20)]. Higher urinary metabolite levels were negatively associated with the ratio of low-density lipoprotein to high-density lipoprotein [Q4 of ttMA compared to reference: ß = -0.06, 95% CI: (-0.11, -0.01); Q4 of BMA compared to reference: ß = -0.13, 95% CI: (-0.19, -0.08)]. CONCLUSION: Benzene and toluene metabolites were significantly and positively associated with hypertriglyceridemia. However, urinary ttMA and BMA levels were negatively associated with high LDL-C levels. These findings suggest that environmental exposure to benzene and toluene disrupts lipid metabolism in humans.

Fasting blood glucose and risk of incident pancreatic cancer.

BACKGROUND: The number of patients with diabetes and impaired fasting blood glucose in Korea is rapidly increasing compared to the past, and other metabolic indicators of population are also changed in recent years. To clarify the mechanism more clearly, we investigated the association between fasting blood glucose and incidence of pancreatic cancer in this retrospective cohort study. METHODS: In Korea National Health Information Database, 19,050 participants without pancreatic cancer in 2009 were enrolled, and followed up until 2013. We assessed the risk of incident pancreatic cancer according to the quartile groups of fasting blood glucose level (quartile 1: <88 mg/dL, quartile 2: 88-97 mg/dL, quartile 3: 97-109 mg/dL and quartile 4: ≥109 mg/dL). Multivariate Cox-proportional hazard model was used in calculating hazard ratios (HRs) and 95% confidence interval (CI) for incident pancreatic cancer. RESULTS: Compared with quartile1 (reference), unadjusted HRs and 95% CI for incident pancreatic cancer significantly increased in order of quartile2 (1.39 [1.01-1.92]), quartile3 (1.50 [1.09-2.07]) and quartile4 (2.18 [1.62-2.95]), and fully adjusted HRs and 95% CI significantly increased from quartile2 (1.47 [1.05-2.04]), quartile3 (1.61 [1.05-2.04]) to quartile4 (2.31 [1.68-3.17]). CONCLUSION: Fasting blood glucose even with pre-diabetic range was significantly associated with the incident pancreatic cancer in Korean.

The association between changes in proteinuria and the risk of cerebral infarction in the Korean population.

BACKGROUND: Proteinuria is a risk factor for cerebral infarction. It is known that proteinuria can change over time. However, published data is scarce for the association between changes in proteinuria and the risk of cerebral infarction. METHOD: Study participants were 276,861 Koreans who were assessed for urine dipstick proteinuria both in 2003-2004 and 2007-2008. They were categorized into four groups by changes in proteinuria over 4 years (negative: negative â†’ negative, resolved: proteinuria ≥ 1+ → negative, incident: negative â†’ proteinuria ≥ 1+, persistent: proteinuria ≥ 1+ → proteinuria ≥ 1 + ). We used multivariate adjusted Cox-proportional hazard model in calculating the adjusted hazard ratios (HR) and 95% confidence interval (CI) for cerebral infarction until 2013 according to changes in proteinuria. RESULT: Adjusted HR and 95% CI for cerebral infarction significantly increased in order of persistent, incident, and resolved proteinuria, compared with negative proteinuria (negative: reference, resolved: 1.166 [1.009-1.347], incident: 1.345 [1.188-1.522], and persistent: 1.443 [1.089-1.912]). In gender subgroup analysis, men showed the more clear association between changes in proteinuria and the risk of cerebral infarction (negative: reference, resolved: 1.284 [1.057-1.560], incident: 1.351 [1.149-1.589], and persistent: 1.428 [1.014-2.012]). CONCLUSION: All types of proteinuria changes were associated with the increased risk of cerebral infarction, even in participants with once manifested but vanishing proteinuria.

The association of pancreatic cancer incidence with smoking status and smoking amount in Korean men.

OBJECTIVES: Our study examined the dose-response relationship between smoking amounts (pack-years) and the risk of developing pancreatic cancer in Korean men. METHODS: Of 125,743 participants who underwent medical health checkups in 2009, 121,408 were included in the final analysis and observed for the development of pancreatic cancer. We evaluated the associations between smoking amounts and incident pancreatic cancer in 4 groups classified by pack-year amounts. Cox proportional hazards models were used to estimate the adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of incident pancreatic cancer by comparing groups 2 (<20 pack-year smokers), 3 (20-≤40 pack-year smokers), and 4 (>40 pack-year smokers) with group 1 (never smokers). RESULTS: During 527,974.5 person-years of follow-up, 245 incident cases of pancreatic cancer developed between 2009 and 2013. The multivariate-adjusted HRs (95% CIs) for incident pancreatic cancer in groups 2, 3, and 4 were 1.05 (0.76 to 1.45), 1.28 (0.91 to 1.80), and 1.57 (1.00 to 2.46), respectively (p for trend=0.025). The HR (95% CI) of former smokers showed a dose-response relationship in the unadjusted model, but did not show a statistically significant association in the multivariate-adjusted model. The HR (95% CI) of current smokers showed a dose-response relationship in both the unadjusted (p for trend=0.020) and multivariate-adjusted models (p for trend=0.050). CONCLUSIONS: The risk of developing pancreatic cancer was higher in current smokers status than in former smokers among Korean men, indicating that smoking cessation may have a protective effect.

Association between urinary trans,trans-muconic acid and diabetes: a cross-sectional analysis of data from Korean National Environmental Health Survey (KoNEHS) cycle 3 (2015-2017).

BACKGROUND: Benzene is a ubiquitous air pollutant that is well known to cause hematopoietic effects in humans including leukemia. Recently, several studies have discussed its non-carcinogenic effects such as diabetes. This study aimed to investigate the association between diabetes and urinary trans,trans-muconic acid (t,t-MA), one of benzene metabolite, using adult data from Korean National Environmental Health Survey (KoNEHS) cycle 3 (2015-2017). METHODS: This study analyzed 3,777 adults (1,645 men and 2,132 women) from the KoNEHS cycle 3 (2015-2017). The distribution and fraction of each independent variable were presented separately according to the urinary benzene metabolite levels (t,t-MA quartiles) and diabetes to determine the general characteristics of the subjects. Odds ratios (ORs) were calculated using logistic regression after stratification by gender and smoking status to identify the association between urinary t,t-MA and diabetes. RESULTS: Compared with the first quartile (reference), the risk of diabetes significantly increased above the 4th (1.834 [1.107-3.039]) quartile in men and above the 3rd (1.826 [1.095-3.044]) and 4th (2.243 [1.332-3.776]) quartiles in women after adjustment. Stratified analysis based on smoking revealed that the ORs for the 3rd (1.847 [1.146-2.976]) and 4th (1.862 [1.136-3.052]) quartiles in non-smokers and those for the 2nd (1.721 [1.046-2.832]), 3rd (1.797 [1.059-3.050]), and 4th (2.546 [1.509-4.293]) quartiles in smokers were significantly higher. CONCLUSIONS: We confirmed that urinary t,t-MA is significantly associated with diabetes regardless of gender and smoking status. And further studies are necessary to access the clinical impacts of this findings.