Relationship between urinary phthalate metabolites and diabetes: Korean National Environmental Health Survey (KoNEHS) cycle 3 (2015-2017)

The mitochondrial link: Phthalate exposure and cardiovascular disease

Phthalates' pervasive presence in everyday life poses concern as they have been revealed to induce perturbing health defects. Utilized as a plasticizer, phthalates are riddled throughout many common consumer products including personal care products, food packaging, home furnishings, and medical supplies. Phthalates permeate into the environment by leaching out of these products which can subsequently be taken up by the human body. It is previously established that a connection exists between phthalate exposure and cardiovascular disease (CVD) development; however, the specific mitochondrial link in this scenario has not yet been described. Prior studies have indicated that one possible mechanism for how phthalates exert their effects is through mitochondrial dysfunction. By disturbing mitochondrial structure, function, and signaling, phthalates can contribute to the development of the foremost cause of death worldwide, CVD. This review will examine the potential link among phthalates and their effects on the mitochondria, permissive of CVD development.

Relationship between endocrine disrupting chemicals (phthalate metabolites, triclosan and bisphenols) and vitamin D in female subjects: An exploratory pilot study

INTRODUCTION

Evidence suggests that endocrine disrupting chemicals (EDCs), commonly used in plastics and personal care products, may be associated with reduced levels of vitamin D. Therefore, this study examined the relationship between phthalate metabolites, 5-chloro-2-(2,4-dichlorophenoxy)phenol (triclosan; TCS) and bisphenols (BPs) with vitamin D3 (25(OH)D3) and active 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), and their relationship to calcium homeostasis.

METHODS

57 female participants (age 31.8 ± 4.6 years; BMI 25.6 ± 3.7 kg/m2) were analyzed for urinary levels of phthalate metabolites, TCS and BPs, and serum levels of 25(OH)D3 and 1,25(OH)2D3, determined by isotope-dilution liquid chromatography tandem mass spectrometry. Serum calcium/calmodulin-dependent (CaM) associated proteins were determined by Slow Off-rate Modified Aptamer (SOMA)-scan.

RESULTS

In the study cohort, 25(OH)D3 and 1,25(OH)2D3 levels were 22.9 ± 11.2 ng/mL and 0.05 ± 0.02 ng/mL, respectively: mono-3-carboxypropyl-phthalate (MCPP) correlated negatively with 25(OH)D3 (ρ = -0.53, p = 0.01). 28 of the 57 women recruited were 25(OH)D3 deficient, <20 ng/mL (50 nmol/L): in this group, mono-iso-butylphthalate (MiBP) and mono-butylphthalate (MBP) negatively correlated with 25(OH)D3; (ρ = -0.47, p = 0.049) and (ρ = -0.64, p = 0.005), respectively. EDCs did not correlate with 1,25(OH)2D3, measures of renal function or CaM proteins.

CONCLUSION

These putative data indicate that MCPP is related to 25(OH)D3, while MiBP and MBP were related to vitamin D deficiency; however, no correlations were observed with TCS and BPs. No phthalate metabolites correlated with 1,25(OH)2D3, CaM associated proteins or renal function, suggesting that effects occur earlier in the vitamin D pathway and not through modulation of cellular calcium flux. The observed correlations are surprisingly strong compared to other predictors of 25(OH)D3, and larger studies adjusting for potential confounders are warranted.

Association of phthalate exposure with all-cause mortality across renal function status: The U.S. National Health and Nutrition Examination Survey, 2005-2018

BACKGROUND

Wide phthalate exposure has been associated with both declines in renal function and an elevated risk of mortality. Whether phthalate-associated risk of premature mortality differs by renal function status remains unclear.

METHODS

This study included 9605 adults from the U.S. National Health and Nutrition Examination Survey. Urinary concentrations of 11 phthalate metabolites were assessed using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry. According to estimated glomerular filtration rate (eGFR), participants were grouped as having normal or modestly declined renal functions, or chronic kidney disease (CKD). Multivariable Cox regression models estimated all-cause mortality associated with phthalate exposure, overall and by renal function status.

RESULTS

Overall, Mono-n-butyl phthalate (MnBP), Mono-benzyl phthalate (MBzP), Mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and Mono-(2-ethyl-5-carbox-ypentyl) phthalate (MECPP) were associated with an elevated risk of mortality (P-trend across tertile <0.05). Moreover, significant interactions were observed between eGFR and MEHHP, MEOHP, MECPP, DEHP in the whole population (P for interactions <0.05). After stratification by renal function, total Di (2-ethylhexyl) phthalate (DEHP) was additionally found to be associated with mortality risk in the CKD group (HR = 1.12; 95% CI: 1.01, 1.25). Co-exposure to the 11 phthalate metabolites was associated with a higher risk of all-cause mortality in the CKD (HR = 1.47; 95% CI: 1.18, 1.84) and modestly declined renal function group (HR = 1.25; 95% CI: 1.09, 1.44).

CONCLUSIONS

The associations between phthalate exposure and risk of all-cause mortality were primarily observed in CKD patients, reinforcing the need for monitoring phthalate exposure in this patient population.

Endoplasmic reticulum stress and pro-inflammatory responses induced by phthalate metabolites monoethylhexyl phthalate and monobutyl phthalate in 1.1B4 pancreatic beta cells

In recent years, phthalates and their metabolites have been associated with metabolic diseases such as diabetes mellitus. To investigate the effects of phthalate metabolites exposure on insulin production and release, 1.1B4 pancreatic beta cells were treated with different concentrations (0.001-1000 µM) of monoethylhexyl phthalate (MEHP) and monobutyl phthalate (MBP). For such purpose, the 1.1B4 cells were evaluated for their viability, apoptosis rate, lysosomal membrane permeabilization (LMP), mitochondrial membrane potential (ΔΨm), oxidative stress, ER stress status, in addition to their secretory functions. MEHP, not MBP, exhibited a notable reduction in metabolic viability, particularly at higher concentrations (500 and 1000 µM) following 24-hour exposure. Similarly, both MEHP and MBP induced decreased metabolic viability at high concentrations after 48- and 72-hour exposure. Notably, neither MEHP nor MBP demonstrated a significant impact on apoptosis rates after 24-hour exposure, and MBP induced mild necrosis at 1000 µM concentration. Cell proliferation rates, indicated by PCNA expression, decreased with 10 and 1000 µM MEHP and 0.1 and 10 µM MBP exposures. LMP analysis revealed an increase in 1000 µM MBP group. Exposure to 0.001 µM of both MEHP and MBP significantly reduced cellular glutathione (GSH) levels. No significant change in intracellular reactive oxygen species (ROS) levels and ΔΨm was observed, but MBP-exposed cells exhibited elevated levels of lipid peroxidation. Functional assessments of pancreatic beta cells unveiled reduced insulin secretion at low glucose concentrations following exposure to both MEHP and MBP, with concurrent alterations in the expression levels of key proteins associated with beta cell function, including GLUT1, GCK, PDX1, and MafA. Moreover, MEHP and MBP exposures were associated with alterations in ER stress-related pathways, including JNK, GADD153, and NF-κB expression, as well as PPARα and PPARγ levels. In conclusion, this study provides comprehensive insights into the diverse impacts of MEHP and MBP on 1.1B4 pancreatic beta cells, emphasizing their potential role in modulating cell survival, metabolic function, and stress response pathways.

The Hidden Threat: Endocrine Disruptors and Their Impact on Insulin Resistance

The association between Insulin resistance, a global health issue, and endocrine disruptors (EDCs), chemicals interfering with the endocrine system, has sparked concern in the scientific community. This article provides a comprehensive review of the existing literature regarding the intricate relationship between EDCs and insulin resistance. Phthalates, commonly found in consumer products, are well-established EDCs with documented effects on insulin-signaling pathways and metabolic processes. Epidemiological studies have connected phthalate exposure to an increased risk of type 2 diabetes mellitus (T2DM). Perfluoroalkyl substances (PFAS), persistent synthetic compounds, have shown inconsistent associations with T2DM in epidemiological research. However, studies suggest that PFAS may influence insulin resistance and overall metabolic health, with varying effects depending on specific PFAS molecules and study populations. Bisphenol A (BPA), found in plastics and resins, has emerged as a concern for glucose regulation and insulin resistance. Research has linked BPA exposure to T2DM, altered insulin release, obesity, and changes in the mass and function of insulin-secreting β-cells. Triclosan, an antibacterial agent in personal care products, exhibits gender-specific associations with T2DM risk. It may impact gut microbiota, thyroid hormones, obesity, and inflammation, raising concerns about its effects on metabolic health. Furthermore, environmental EDCs like polycyclic aromatic hydrocarbons, pesticides, and heavy metals have demonstrated associations with T2DM, insulin resistance, hypertension, and obesity. Occupational exposure to specific pesticides and heavy metals has been linked to metabolic abnormalities.

Food contaminants and potential risk of diabetes development: A narrative review

The number of people diagnosed with diabetes continues to increase, especially among younger populations. Apart from genetic predisposition and lifestyle, there is increasing scientific and public concern that environmental agents may also contribute to diabetes. Food contamination by chemical substances that originate from packaging materials, or are the result of chemical reactions during food processing, is generally recognized as a worldwide problem with potential health hazards. Phthalates, bisphenol A (BPA) and acrylamide (AA) have been the focus of attention in recent years, due to the numerous adverse health effects associated with their exposure. This paper summarizes the available data about the association between phthalates, BPA and AA exposure and diabetes. Although their mechanism of action has not been fully clarified, in vitro, in vivo and epidemiological studies have made significant progress toward identifying the potential roles of phthalates, BPA and AA in diabetes development and progression. These chemicals interfere with multiple signaling pathways involved in glucose and lipid homeostasis and can aggravate the symptoms of diabetes. Especially concerning are the effects of exposure during early stages and the gestational period. Well-designed prospective studies are needed in order to better establish prevention strategies against the harmful effects of these food contaminants.

The Relationship between Phthalates and Diabetes: A Review

Since the beginning of their production, in the 1930s, phthalates have been widely used in the plastics industry to provide durability and elasticity to polymers that would otherwise be rigid, or as solvents in hygiene and cosmetic products. Taking into account their wide range of applications, it is easy to understand why their use has been increasing over the years, making them ubiquitous in the environment. This way, all living organisms are easily exposed to these compounds, which have already been classified as endocrine disruptor compounds (EDC), affecting hormone homeostasis. Along with this increase in phthalate-containing products, the incidence of several metabolic diseases has also been rising, namely diabetes. That said, and considering that factors such as obesity and genetics are not enough to explain this substantial increase, it has been proposed that the exposure to environmental contaminants may also be a risk factor for diabetes. Thus, the aim of this work is to review whether there is an association between the exposure to phthalates and the development of the several forms of diabetes mellitus, during pregnancy, childhood, and adulthood.

Endocrine disruptors in plastics alter β-cell physiology and increase the risk of diabetes mellitus

Plastic pollution breaks a planetary boundary threatening wildlife and humans through its physical and chemical effects. Of the latter, the release of endocrine disrupting chemicals (EDCs) has consequences on the prevalence of human diseases related to the endocrine system. Bisphenols (BPs) and phthalates are two groups of EDCs commonly found in plastics that migrate into the environment and make low-dose human exposure ubiquitous. Here we review epidemiological, animal, and cellular studies linking exposure to BPs and phthalates to altered glucose regulation, with emphasis on the role of pancreatic β-cells. Epidemiological studies indicate that exposure to BPs and phthalates is associated with diabetes mellitus. Studies in animal models indicate that treatment with doses within the range of human exposure decreases insulin sensitivity and glucose tolerance, induces dyslipidemia, and modifies functional β-cell mass and serum levels of insulin, leptin, and adiponectin. These studies reveal that disruption of β-cell physiology by EDCs plays a key role in impairing glucose homeostasis by altering the mechanisms used by β-cells to adapt to metabolic stress such as chronic nutrient excess. Studies at the cellular level demonstrate that BPs and phthalates modify the same biochemical pathways involved in adaptation to chronic excess fuel. These include changes in insulin biosynthesis and secretion, electrical activity, expression of key genes, and mitochondrial function. The data summarized here indicate that BPs and phthalates are important risk factors for diabetes mellitus and support a global effort to decrease plastic pollution and human exposure to EDCs.

Phthalates' exposure leads to an increasing concern on cardiovascular health

Being an essential component in the plastics industry, phthalates are ubiquitous in the environment and in everyday life. They are considered environmental contaminants that have been classified as endocrine-disrupting compounds. Despite di-2-ethylhexyl phthalate (DEHP) being the most common plasticizer and the most studied to date, there are many others that, in addition to being widely used in the plastic, are also applied in the medical and pharmaceutical industries and cosmetics. Due to their wide use, phthalates are easily absorbed by the human body where they can disrupt the endocrine system by binding to molecular targets and interfering with hormonal homeostasis. Thus, phthalates exposure has been implicated in the development of several diseases in different age groups. Collecting information from the most recent available literature, this review aims to relate human phthalates' exposure with the development of cardiovascular diseases throughout all ages. Overall, most of the studies presented demonstrated an association between phthalates and several cardiovascular diseases, either from prenatal or postnatal exposure, affecting foetuses, infants, children, young and older adults. However, the mechanisms underlying these effects remain poorly explored. Thus, considering the cardiovascular diseases incidence worldwide and the constant human exposure to phthalates, this topic should be extensively studied to understand the mechanisms involved.

Urinary phthalate concentrations and mortality risk: A population-based study

Phthalates are widely used as plasticizers. Laboratory-based mechanistic and epidemiological studies suggest that phthalates are detrimental to human health. Here, we present prospective analyses on phthalate exposure and all-cause, as well as cause-specific, mortality from the National Health and Nutrition Examination Survey (NHANES), a population-based cohort. Between 1999 and 2018, urinary concentrations of 12 phthalate metabolites were measured by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry in spot urine samples of 10,881 adults aged 40-85 years, of which 2382 died over a median duration of 8.9 years after sample provision. Multivariable Cox regression analyses adjusted for a wide range of lifestyle factors and comorbidities showed that higher concentrations of mono-benzyl phthalate (MBzP) and Mono-n-butyl phthalate (MnBP) were associated with increased mortality. The hazard ratios for participants in the highest quartiles of MBzP and MnBP concentrations were at 1.27 [95% confidence interval: 1.08, 1.49; p _{linear trend} = 0.002] and 1.35 [1.13, 1.62; p _{linear trend} = 0.005). These findings reinforce the need for monitoring of phthalate exposure in relation to health outcomes.

A Pilot Study: Nails as a Non-invasive Biospecimen of Human Exposure to Phthalate Esters

Human biomonitoring provides a scientific approach that systematically reveals exposure to phthalates through all possible routes. In this pilot study, fingernail was chosen as a non-destructive biospecimen to assess human exposure to nine phthalates. Concentrations of total phthalates ranged from 17.8 to 176 µg/g (median: 65.4 µg/g). Di(2-ethylhexyl) phthalate, dibutyl phthalate (DBP), and di-isobutyl phthalate were the major compounds found in fingernails, accounting for 64.3%, 19.4%, and 12.9% of the total phthalates, respectively. No significant difference in phthalates concentrations was found among genders and age-related distribution (p > 0.05). The concentration of DBP was positively correlated with participant's body mass index (r = 0.83). Our results suggested that fingernail can be used as a non-invasive biospecimen for the biomonitoring of human exposure to phthalates. Further studies are needed to investigate the relationship between phthalates or their metabolites in fingernail and other biological samples, such as urine and blood.

Phthalate exposure and risk of diabetes mellitus: Implications from a systematic review and meta-analysis

BACKGROUND

Epidemiologic studies indicated that phthalate exposure might be associated with diabetes mellitus (DM). However, discrepancies existed. The link between phthalate exposure and risk of DM remained unclarified.

METHODS

We conducted a meta-analysis to explore the association between phthalate exposure and risk of DM. Effects of phthalate exposure on insulin resistance were also evaluated by systematic review.

RESULTS

Seven studies involving 12,139 participants were included in this meta-analysis. Our results showed that urinary concentrations of phthalates were positively associated with risk of DM. The pooled ORs were 3.11 (95% CI: 1.16-8.37) for monomethyl phthalate (MMP), 1.27 (95% CI: 1.03-1.56) for mono-n-butyl phthalate (MnBP), 2.59 (95% CI: 1.10-6.10) for mono-isobutyl phthalate (MiBP), 1.99 (95% CI: 1.52-2.61) for mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), 1.90 (95% CI: 1.40-2.57) for mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), 1.55 (95% CI: 1.10-2.20) for mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP), and 2.39 (95% CI: 1.18-4.85) for mono-(3-carboxypropyl) phthalate (MCPP), respectively. Molar summation of di-2-ethylhexyl phthalate metabolites (∑DEHP) was also found to be correlated with risk of DM (OR 2.15, 95% CI: 1.48-3.13). No significant association with risk of DM was found regarding monoethyl phthalate (MEP), monobenzyl phthalate (MBzP) and mono(2-ethylhexyl) phthalate (MEHP). In literature review, most studies showed positive correlations of phthalates, especially ∑DEHP, with homeostasis model assessment of insulin resistance and fasting glucose.

CONCLUSION

Exposure to phthalates, especially MMP, MnBP, MiBP, MCPP and DEHP metabolites, might be a risk factor of DM. Our results should be interpreted with caution due to heterogeneous design of enrolled studies.

Mixtures modeling identifies heavy metals and pyrethroid insecticide metabolites associated with obesity

We aim to examine the association between chemical mixtures and obesity. Blood and urinary levels of tween-six chemicals were measured in adults who participated in the KoNEHS. We identified the associations of chemicals with obesity using linear regression models. Weighted quantile sum (WQS) regression, quantile g-computation (qgcomp), and Bayesian kernel machine regression (BKMR) were conducted as secondary analyses. Of the 3,692 participants included in the analysis, 18.0% had obesity. In the logistic regression model, mercury (Hg), lead (Pb), and 3PBA levels were associated with obesity, and significant trends were observed for these chemical tertiles (p < 0.001). Hg, Pb, and 3PBA levels were also associated with BMI. The WQS index was significantly associated with both obesity (OR = 2.15, 95% CI: 2.11-2.20) and BMI (β = 0.39, 95% CI: 0.37-0.51). The qgcomp index also found a significant association between chemicals and both obesity (OR = 1.70, 95% CI: 1.56-1.85) and BMI (β = 0.40, 95% CI: 0.39-0.41). Hg, Pb, and 3PBA were the most heavily weighed chemicals in these models. In BKMR analysis, the overall effect of the mixture was significantly associated with obesity. Hg, Pb, and 3PBA showed positive trends and were observed as the most important factors associated with obesity. Given increasing exposure to chemicals, there is a need to investigate the associations between chemical exposures, either separately or together, and incident obesity risk factors in well-characterized cohorts of different populations, and to identify potential approaches to chemical exposure prevention.

Urinary bisphenol concentrations and its association with metabolic disorders in the US and Korean populations

Bisphenol A (BPA) is a representative endocrine disrupting compound used in a vast array of consumer products, and are being frequently substituted by its analogues, bisphenol S (BPS) and bisphenol F (BPF). We aimed to examine the association between urinary bisphenol levels with obesity and lipid profiles in the general population to comprehensively evaluate its potential of metabolic disturbance. A representative sample of 1046 US adults from the National Health and Nutrition Examination Survey (2013-2016) and 3268 Korean adults from the Korean National Environmental Health Survey (2015-2017) was analyzed. We examined the exposure levels of bisphenols and determined their associations with obesity, high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG) levels, and hypercholesterolemia prevalence through multiple linear, and binary/ordinal logistic regression models. In both populations, high BPA levels (lowest tertile vs. 2nd, 3rd tertiles) showed corresponding associations with lipid profile and obesity. BPA levels were associated with decreased HDL-C levels (Q3: β = -0.053, p = 0.08 (US); Q2: β = -0.030, p-0.03), increased TG levels (Q3: β = 0.121, p = 0.029 (US); Q3: β = 0.089, p = 0.021, and higher odds for obesity (Q3: OR = 1.58, 95% CI: 1.06, 2.35 (US); Q3: OR = 1.41, 95% CI: 1.11, 1.78). Higher BPS levels were positively associated with obesity status, especially in US men (Q2: OR = 1.84, 95% CI: 1.15, 2.96) and Korean women (Q3: OR = 1.27, 95% CI: 0.99, 1.64). A significant decrease in HDL-C (Q3: β = -0.088, p = 0.01) and elevated odds for obesity at higher BPF levels (Q3: OR = 1.60, 95% CI: 1.00, 2.56) was observed in US women. The findings of our study indicate that BPA and its analogues, BPS and BPF, are associated with lipid metabolism disorders in addition to obesity in adults. Given the increase in exposure to BPA alternatives, continuous biomonitoring, and further investigation of their health effects through prospective cohort studies are warranted.

Association between exposure to chemical mixtures in relation to serum total IgE among adults 19-86 years old

There is a scarcity of studies on the effects of mixed chemicals on total IgE. We aim to assess whether there is a link between chemical mixtures (blood and urine of 26 chemicals including lead, mercury, cadmium, t,t-muconic acid, benzylmercapturic acid , 1-hydroxypyrene, 2-naphthol, 2-hydroxyfluorene, 1-hydroxyphenanthrene, mono-(2-ethyl-5-hydroxyhexyl) phthalate, mono-(2-ethyl-5-oxohexyl) phthalate, mono-n-butyl phthalate, mono-benzyl phthalate, mono-(2-ethyl-5-carboxypentyl) phthalate, mono-carboxyoctyl phthalate, mono-carboxy-isononly phthalate, mono (3-carboxypropyl) phthalate, bisphenol A, bisphenol F, bisphenol S, triclosan, methylparaben, ethylparaben, propylparaben, 3-phenoxybenzoic acid, and cotinine), and total IgE in 3,642 Korean adults aged ≥ 19. The effects of mixed chemical exposure on total IgE were identified using linear regression models, weighted quantile sum (WQS) regression, quantile g-computation (qgcomp), and Bayesian kernel machine regression (BKMR). The most relevant factors linked with IgE, according to the linear regression models, were blood or urine mercury and urine bisphenol A levels, with significant trends detected for these chemical tertiles (p < 0.01). The WQS index was significantly linked with ln2-transformed levels of serum total IgE (β = 0.30, 95 %CI 0.25-0.32). The qgcomp index also found a significant link between chemicals and ln2-transformed levels of serum total IgE (β = 0.52, 95 %CI 0.21-0.82), and elevated serum total IgE levels (OR = 2.55, 95 %CI 1.14-5.71). In BKMR analysis, the overall effect of the mixture was significantly associated with ln2-transformed levels of serum total IgE. The cutoff levels for exposure levels related to serum total IgE levels/elevated serum total IgE levels were reported. We discovered that whole-body exposure to 26 chemicals was associated with serum total IgE levels after assessing the findings of these four models. More research is needed in the future to gain a better understanding of the impact of mixed chemical exposure on allergic disorders and how to minimize chemical exposure, especially for people under the age of 18.

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.