Occupational metal exposures, smoking and risk of diabetes and prediabetes

Combined exposure to multiple metals on abdominal aortic calcification: results from the NHANES study

Exposure to metals increases the risk of many diseases and has become a public health concern. However, few studies have focused on the effect of metal on abdominal aortic calcification (AAC), especially the combined effects of metal mixtures. In this study, we aim to investigate the combined effect of metals on AAC risk and determine the key components in the multiple metals. We tried to investigate the relationship between multiple metal exposure and AAC risk. Fourteen urinary metals were analyzed with five statistical models as follows: generalized linear regression, weighted quantile sum regression (WQS), quantile g-computation (Qgcomp), and Bayesian kernel machine regression (BKMR) models. A total of 838 participants were involved, of whom 241 (28.8%) had AAC. After adjusting for covariates, in multiple metal exposure logistic regression, cadmium (Cd) (OR = 1.364, 95% CI = 1.035-1.797) was positively associated with AAC risk, while cobalt (Co) (OR = 0.631, 95% CI = 0.438-0.908) was negatively associated with AAC risk. A significant positive effect between multiple metal exposure and AAC risk was observed in WQS (OR = 2.090; 95% CI = 1.280-3.420, P < 0.01), Qgcomp (OR = 1.522, 95% CI = 1.012-2.290, P < 0.05), and BKMR models. It was found that the positive association may be driven primarily by Cd, lead (Pb), uranium (U), and tungsten (W). Subgroups analysis showed the association was more significant in participants with BMI ≥ 25 kg/m2, abdominal obesity, drinking, and smoking. Our study shows that exposure to multiple metals increases the risk of AAC in adults aged ≥ 40 years in the USA and that Cd, Pb, U, and W are the main contributors. The association is stronger in participants who are obese, smoker, or drinker.

A nested case-control study of serum zinc and incident diabetes among Chinese adults: Effect modifications and mediation analysis

Although numerous evidences suggest that zinc may have a beneficial impact on preventing and treating diabetes, findings from the population studies are inconclusive. To address this gap, we conducted a nested case-control study, employing restricted cubic splines and a conditional logistic regression model to explore the association between serum zinc levels and the risk of diabetes. We also assessed potential effect modifications through stratified analyses and examined the mediating effects of metabolic indicators using a multiclass mediation effect model. We measured baseline serum zinc concentrations using Inductively Coupled Plasma Mass Spectrometry in a cohort of 2156 participants, including 1078 individuals with diabetes and 1078 matched controls. Our findings revealed a 51 % increased risk of diabetes when comparing the highest quartile (Q4) to the lowest quartile (Q1) of serum zinc levels (Odds Ratio [95 % Confidence Interval]: 1.51 [1.09, 2.09]). There was a positive linear dose-response relationship between serum zinc and diabetes risk (P overall ≤0.01, P nonlinear = 0.20). Effect modifications were evident between serum zinc and factors such as educational attainment, body mass index, alcohol index, family history of diabetes, history of hypertension, coronary heart disease, and stroke, all of which influenced the risk of diabetes (all P-interaction <0.05). Moreover, our study identified significant indirect effects of triglycerides levels on diabetes risk for participants in the third (Q3) and fourth (Q4) quartiles of serum zinc, with mediation proportions of 19.23 % and 19.28 %, respectively. A significant indirect effect of alanine aminotransferase on diabetes risk was found for those in the Q4 of serum zinc, with a mediation proportion of 12.05 %. Considering these findings, it is advisable to conduct testing for serum zinc level and exercise caution when considering zinc supplementation. Furthermore, our results emphasized the necessity for additional validation through large-sample prospective population studies and experimental research.

The associations of non-essential metal mixture with fasting plasma glucose among Chinese older adults without diabetes

The evidence about the effect of non-essential metal mixture on fasting plasma glucose (FPG) levels among older adults without diabetes is limited. This study aims to estimate the individual and joint relationship between five non-essential metals and FPG levels in Chinese older adults without diabetes. This study included 2362 older adults without diabetes. Urinary concentrations of five non-essential metals, i.e., cesium (Cs), aluminum (Al), thallium (Tl), cadmium (Cd), and arsenic (As), were detected by inductively coupled plasma mass spectrometry (ICP-MS). The associations of single metals and the metal mixture with FPG levels were assessed using linear regression and Bayesian kernel machine regression (BKMR) models, respectively. Adjusted single-metal linear regression models showed positive associations of urinary Al (β = 0.016, 95%CI: 0.001-0.030) and Cs (β = 0.018, 95%CI: 0.006-0.031) with FPG levels. When comparing the 2th, 3th, and 4th quartiles of urine Cs to its 1th quartile, the significant associations between Cs and FPG levels were found and presented as an "inverted U" trend (βQ2 vs. Q1: 0.034; βQ3 vs. Q1:0.054; βQ4 vs. Q1: 0.040; all P<0.05). BKMR analyses showed urinary level of Cs exhibited an "inverted U" shape association with FPG levels. Moreover, the FPG levels increased linearly with the raised levels of the non-essential metal mixture, and the posterior inclusion probability (PIP) of Cs was the highest (0.92). Potential positive interaction of As and Cs on FPG levels was found in BKMR model. Stratified analysis displayed significant interactions of hyperlipidemia and urine Cs or Tl on FPG levels. An inverse U-shaped association between Cs and FPG was found, individually and as mixture. The FPG levels increased with the raised levels of the non-essential metal mixture, and Cs was the most contributor to FPG levels. Further research is required to confirm the correlation between non-essential metals and FPG levels and to clarify the underlying mechanisms.

Metal Exposure, Smoking, and the Risk of COPD: A Nested Case-Control Study in a Chinese Occupational Population

Chronic obstructive pulmonary disease (COPD) was the third leading cause of death worldwide in 2019, with a significant disease burden. We conducted a nested case-control study using data from the China Metal-Exposed Workers Cohort Study (Jinchang Cohort) and assessed the associations of exposure to metals and tobacco smoking with the risk of COPD. We used the logistic regression model and the interaction multiplication model to assess the independent and combined effects of heavy metal and smoke exposure on COPD. The cumulative incidence of COPD was 1.04% in 21,560 participants during a median of two years of follow-up. The risk of COPD was significantly elevated with an increase in the amount of tobacco smoked daily (p < 0.05), the number of years of smoking (p_trend < 0.05), and the number of packs of cigarettes smoked per year (p_trend < 0.01). Compared with the low metal exposure group, the adjusted OR was 1.22 (95% CI: 0.85-1.76) in the medium exposure group (mining/production workers) and 1.50 (95% CI: 1.03-2.18) in the high exposure group; smoking and metal exposure had a combined effect on the incidence of COPD (p_interaction < 0.01), with an OR of 4.60 for those with >40 pack-years of smoking who also had the highest metal exposures. Both exposures to metals and smoking were associated with the risk of COPD, and there was an interaction between the two exposures for the risk of COPD.

Cohort Profile Update: the China Metal-Exposed workers Cohort Study (Jinchang Cohort)

The Jinchang Cohort was an ongoing 20-year ambispective cohort with unique metal exposures to an occupational population. From January 2014 to December 2019, the Jinchang Cohort has completed three phases of follow-up. The baseline cohort was completed from June 2011 to December 2013, and a total of 48 001 people were included. Three phases of follow-ups included 46 713, 41 888, and 40 530 participants, respectively. The death data were collected from 2001 to 2020. The epidemiological, physical examination, physiological, and biochemical data of the cohort were collected at baseline and during follow-up. Biological specimens were collected on the baseline to establish a biological specimen bank. The concentrations of metals in urine and serum were detected by inductively coupled plasma mass spectrometry (ICP-MS). The new areas of research aim to study the all-cases mortality, the burden of diseases, heavy metals and diseases, and the course of the chain from disease to high-risk outcomes using a combination of macro and micro means, which provided a scientific basis to explore the pathogenesis of multi-etiology and multi-disease and to evaluate the effects of the intervention measures in the population.

Associations of RBC and Serum Folate Concentrations with Cervical Intraepithelial Neoplasia and High-Risk Human Papillomavirus Genotypes in Female Chinese Adults

BACKGROUND

Although folate status is associated with cervical carcinogenesis, it is not clear whether folate deficiency is associated with risk of cervical intraepithelial neoplasia (CIN) progression and infection with high-risk human-papillomavirus (hrHPV).

OBJECTIVES

To evaluate the associations of RBC and serum folate concentrations with prevalence of CIN grades and hrHPV infection, their interactions with prevalence of CIN grades, and RBC folate with the risk of CIN1 progressing to CIN2.

METHODS

Using data from the Shanxi CIN cohort of 2304 female Chinese adults, we used logistic-regression model to estimate ORs and prevalence ratios (PRs) of RBC and serum folate concentrations with prevalence of CIN grades and hrHPV infection. Categoric and spline analyses were used to evaluate the dose-response relations. We estimated the association of RBC folate with risk of CIN1 progressing to CIN2 in the nested case-control cohort.

RESULTS

An inverse association was observed between increased RBC folate concentration and the odds of all CIN grades [quartile 1 (Q1) compared with Q4: OR: 2.28; 95% CI: 1.77, 2.93; Ptrend < 0.001]. Significant interaction of RBC folate and hrHPV infection was observed for prevalence of CIN2 or above (Pinteraction < 0.01). No associations were found between RBC and serum folate with PRs of hrHPV in each CIN grade. Over a median follow-up of 21.0 mo, RBC folate was associated with increased risk of CIN1 progressing to CIN2 (Q1 compared with Q4: OR: 3.86; 95% CI: 1.01, 14.76).

CONCLUSIONS

Our study indicates that RBC folate concentration is associated with prevalence of CIN grades and CIN1 progression in female Chinese adults. Maintenance of normal folate status is important for reducing the risk of CIN and its progression in women with or without hrHPV infection.

The Prevalence of Diabetes, Prediabetes and Associated Risk Factors in Hangzhou, Zhejiang Province: A Community-Based Cross-Sectional Study

OBJECTIVE

Little information is available on the prevalence and associated risk factors of diabetes and prediabetes in the community located in Hangzhou city, Zhejiang Province, southeast China. This study aims to investigate the prevalence of adult diabetes and prediabetes and their associated risk factors among a community population in Hangzhou.

METHODS

A multistage sampling method was used in this study. Ten communities located in Shangcheng district of Hangzhou city were selected, and 3096 permanent residents (resident for ≥6 months) aged 18 years and above were enrolled into this study. Finally, a total of 2986 participants were included. A questionnaire interview and physical examination were conducted for all participants by trained investigators in a local medical center. Anthropometric measurements covered height, weight, waist circumference (WC) and blood pressure, while the blood tests included fasting blood glucose, an oral glucose tolerance test and fasting lipid profiles. The American Diabetes Association diabetes diagnosis criteria were used to discriminate among normal blood glucose, diabetes and prediabetes. The Rao-Scott adjusted χ ² test and complex sampling design-based unconditional multivariate logistic regression analysis were used to evaluate factors associated with diabetes and prediabetes. Descriptive and inferential statistics were calculated in Stata version 15. P-values <0.05 indicate statistical significance.

RESULTS

The overall prevalence of diabetes was 13.97%, of which 81.54% had prediagnosed diabetes and 18.46% were newly diagnosed with diabetes in the present study. The prevalence of prediabetes was 18.89%. Multivariable logistic regression analysis showed that age, education, once smoking, family history of diabetes, obesity, central obesity and hypertension were factors associated with diabetes, while age, smoking, drinking, central obesity and hypertension were significant factors related to prediabetes.

CONCLUSION

The prevalence of diabetes and prediabetes in adults in Hangzhou city remains high. Interventions aiming to modify risk factors such as drinking, obesity, central obesity and hypertension are urgently required.

Differential risk factor profile of diabetes and atherosclerosis in rural, sub-urban and urban regions of South India: The KMCH-Non-communicable disease studies

AIMS

South Asia has emerged rapidly as an epicentre of non-communicable diseases (NCDs) specifically diabetes and cardiovascular diseases. The prevalence rate, risk factors and aetiology of NCDs in different socio-demographic settings are not clearly understood. This study was performed to assess the prevalence of diabetes and atherosclerosis and their risk factors in urban, sub-urban and rural communities of South India.

METHODS

Three communities [Nallampatti (rural), Thadagam (sub-urban) and Kalapatti (urban)] in South India were selected for participation in the KMCH-NCD Studies. Study volunteers were administered a detailed questionnaire, underwent anthropometric measurements, clinical measurements including blood pressure, glycated haemoglobin (HbA_1c ), non-fasting lipid profile and serum creatinine. Carotid intima-media thickness was measured using B-mode ultrasound. Multiple logistic regression analyses were performed to understand the association of risk factors with diabetes and atherosclerosis.

RESULTS

A total of 2976 native participants, ≥20 years of age were screened. The prevalence of diabetes was 16%, 26% and 23% respectively in the rural, sub-urban and urban study populations. Association of obesity with diabetes was observed in only urban population while hypertension and dyslipidaemia showed association in both urban and semi-urban populations. Association of diabetes with atherosclerosis was observed in urban and semi-urban populations. Hypertension in semi-urban and obesity and dyslipidaemia in urban population showed association with atherosclerosis.

CONCLUSIONS

Diabetes and atherosclerosis burden reported in the three different communities were higher than previous reports, especially in rural and sub-urban regions. No traditional risk factor is identified to be associated with prevalence of diabetes and atherosclerosis in rural population. These findings suggest an urgent need for investigation into the role of non-traditional risk factors like environmental or occupational exposures may help to better understand the aetiology of diseases in non-urbanized communities.

Cumulative Risks from Stressor Exposures and Personal Risk Factors in the Workplace: Examples from a Scoping Review

Protecting worker and public health involves an understanding of multiple determinants, including exposures to biological, chemical, or physical agents or stressors in combination with other determinants including type of employment, health status, and individual behaviors. This has been illustrated during the COVID-19 pandemic by increased exposure and health risks for essential workers and those with pre-existing conditions, and mask-wearing behavior. Health risk assessment practices for environmental and occupational health typically do not incorporate multiple stressors in combination with personal risk factors. While conceptual developments in cumulative risk assessment to inform a more holistic approach to these real-life conditions have progressed, gaps remain, and practical methods and applications are rare. This scoping review characterizes existing evidence of combined stressor exposures and personal factors and risk to foster methods for occupational cumulative risk assessment. The review found examples from many workplaces, such as manufacturing, offices, and health care; exposures to chemical, physical, and psychosocial stressors combined with modifiable and unmodifiable determinants of health; and outcomes including respiratory function and disease, cancers, cardio-metabolic diseases, and hearing loss, as well as increased fertility, menstrual dysfunction and worsened mental health. To protect workers, workplace exposures and modifiable and unmodifiable characteristics should be considered in risk assessment and management. Data on combination exposures can improve assessments and risk estimates and inform protective exposure limits and management strategies.

Sex-specific associations of plasma metals and metal mixtures with glucose metabolism: An occupational population-based study in China

Studies with multi-pollutant approach on the relationships between multiple metals and fasting plasma glucose (FPG) are limited. Few studies are available on the potential sex-specific associations between metal exposures and glucose metabolism. We explored the associations between 22 plasma metals and FPG level among the 769 participants from the manganese-exposed workers healthy cohort in China. We applied a sparse partial least squares (sPLS) regression followed by ordinary least-squares regression to evaluate multi-pollutant association. Bayesian kernel machine regression (BKMR) model was used to deal with metal mixtures and evaluate their joint effects on FPG level. In the sPLS model, negative associations on FPG levels were observed for plasma iron (belta = -0.066), cobalt (belta = -0.075), barium (belta = -0.109), and positive associations for strontium (belta = 0.082), and selenium (belta = 0.057) in men, which overlapped with the results among the overall participants. Among women, plasma copper (belta = 0.112) and antimony (belta = 0.137) were positively associated with elevated FPG level. Plasma magnesium was negatively associated with FPG level in both sexes (belta = -0.071 in men and belta = -0.144 in women). The results of overlapped for plasma magnesium was selected as the significant contributor to decreasing FPG level in the multi-pollutant, single-metal, and multi-metal models. BKMR model showed a significantly negative over-all effect of six metal mixtures (magnesium, iron, cobalt, selenium, strontium and barium) on FPG level among the overall participants from all the metals fixed at 50th percentile. In summary, our findings underline the probable role of metals in glucose homeostasis with potential sex-dependent heterogeneities, and suggest more researches are needed to explore the sex-specific associations of metal exposures with risk of diabetes.

Assessing different anthropometric indices and their optimal cutoffs for prediction of type 2 diabetes and impaired fasting glucose in Asians: The Jinchang Cohort Study

BACKGROUND

To study the association between anthropometric measurements and the risk of diabetes and impaired fasting glucose (IFG) and compare body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR) to determine the best indicator and its optimal cutoffs for predicting type 2 diabetes and IFG.

METHODS

A Chinese prospective (2011-2019) cohort named the Jingchang cohort that included 48 001 participants was studied. Using Cox proportional hazard models, hazard ratios (HRs) for incident type 2 diabetes or IFG per 1 SD change in BMI, WC, and WHtR were calculated. Area under the curve (AUC) was compared to identify the best anthropometric variable and its optimal cutoff for predicting diabetes.

RESULTS

The association of BMI, WC, and WHtR with type 2 diabetes or IFG risk was positive in the univariate and multivariable-adjusted Cox proportional hazard models. Of all three indexes, the AUC of BMI was largest and that of WC was smallest. The derived cutoff values for BMI, WC, and WHtR were 24.6 kg/m² , 89.5 cm, and 0.52 in men and 23.4 kg/m² , 76.5 cm, and 0.47 in women for predicting diabetes, respectively. The derived cutoff values for BMI, WC, and WHtR were 23.4 kg/m² , 87.5 cm, and 0.50 in men and 22.5 kg/m² , 76.5 cm, and 0.47 in women for predicting IFG, respectively. [Correction added on 14 April 2020, after first online publication: '0' has been deleted from 'WC,0' in the first sentence.].

CONCLUSIONS

Our derived cutoff points were lower than the values specified in the most current Asian diabetes guidelines. We recommend a cutoff point for BMI in Asians of 23 kg/m² and for WC a cutoff point of 89 cm in men and 77 cm in women to define high-risk groups for type 2 diabetes; screening should be considered for these populations.

Occupational exposure to heavy metals, alcohol intake, and risk of type 2 diabetes and prediabetes among Chinese male workers

OBJECTIVE

Both exposure to heavy metals and alcohol intake have been related to the risk of type 2 diabetes (T2D). In this study, we aimed to assess the potential interactions between metal exposure and alcohol intake on the risk of T2D and prediabetes in a cohort of Chinese male workers.

METHODS

We conducted a cross-sectional analysis of 26,008 Chinese male workers in an occupational cohort study from 2011 to 2013. We assessed metal exposure and alcohol consumption at baseline in these workers who were aged ≥20 years. Based on occupations which were categorized according to measured urine metal levels, multiple logistic regression analyses were used to evaluate the independent and joint effects of metal and alcohol exposure on the risk of T2D and prediabetes.

RESULTS

Risks of T2D (P trend = 0.001) and prediabetes (P trend = 0.001) were significantly elevated with increasing number of standard drinks per week, years of drinking, and lifetime alcohol consumption. An adjusted odds ratio (OR) of 6.1 (95% confidence interval [CI]: 4.8-7.8) was observed for the smelting/refining workers (highest metal exposure levels) who had the highest lifetime alcohol consumption (>873 kg) (P interaction = 0.018), whereas no statistically significant joint effect was found for prediabetes (P interaction = 0.515).

CONCLUSIONS

Both exposures to metal and heavy alcohol intake were associated with the risk of diabetes in this large cohort of male workers. There was a strong interaction between these two exposures in affecting diabetes risk that needs to be confirmed in future studies.

Occupational Risk Factors and the Relationship of Smoking with Anxiety and Depression

OBJECTIVES

The aim of the present study was to evaluate the relation of smoking with anxiety and depression in workers who were exposed to occupational risk factors. For this purpose, working time, smoking status, nicotine dependence, and respiratory functions of the workers who were exposed to physical and/or chemical harmful substances were evaluated and the presence of anxiety/depression was investigated.

MATERIAL AND METHODS

Male workers who were exposed to occupational risk factors such as solvents, heavy metals, and dust and visited the outpatient clinic for occupational diseases within a one-year period were included. Pulmonary Function Test and Fagerström Test for Nicotine Dependence were performed. Anxiety and depression statuses of the workers were assessed using the Hospital Anxiety and Depression Scale.

RESULTS

The mean age of 665 male workers was 45 y (range, 38-48 y), and they were most commonly exposed to solvents (45.9%), followed by heavy metal fume/dust (20.9%). Of the workers, 252 (37.9%) had anxiety, 294 (44.2%) had depression, and 171 (25.7%) had both. More than half of the workers in each occupation/exposure group were smokers. Respiratory complaints were present in 34% of the workers. According to the regression analysis, the presence of respiratory system complaints was found to be a significant risk factor for anxiety, depression, and anxiety plus depression.

CONCLUSION

In conclusion, smoking and anxiety/depression were found to be the conditions affecting more than half of the workers with occupational exposure.