Blood lead level risk factors and reference value derivation in a cross-sectional study of potentially lead-exposed workers in Iran

Association between lead and circulating markers of inflammation among traffic enforcers in Metro Manila, Philippines: the MMDA traffic enforcer's health study

PURPOSE

Several epidemiological studies have linked lead (Pb) exposure to induced oxidative stress and the promotion of inflammatory response. We performed a within-subjects study (repeated measures study) to evaluate the relationship between the concentration of blood lead (B-Pb) and toenail lead (T-Pb) and circulating markers of inflammation.

METHODS

We evaluated the associations between B-Pb concentrations and T-Pb concentrations and circulating markers of inflammation, soluble intracellular adhesion molecule-1 (s-ICAM-1), soluble vascular adhesion molecule-1 (s-VCAM-1), and high-sensitivity C-reactive protein (hs-CRP) on 158 traffic enforcers from the Metropolitan Manila Development Authority (MMDA) traffic enforcer's health study. Linear mixed-effects models with random subject-specific intercepts were fitted to estimate the association between B-Pb and T-Pb exposure and circulating markers of inflammation, adjusting for confounding factors.

RESULTS

Traffic enforcers were middle-aged men (89.4%) with a mean age (± SD) of 37.1 years ± 8.9 years and had a total of 293 valid markers of inflammation measurements. B-Pb concentration was related to increased hs-CRP levels. A 10% increase in B-Pb was associated with a 5.7% increase in hs-CRP level [95% confidence interval (95% CI): 1.3-10.1]. However, B-Pb was not associated with s-ICAM-1 and s-VCAM-1. Furthermore, no associations were observed between T-Pb and all the circulating markers of inflammation.

CONCLUSIONS

Low-level B-Pb may increase hs-CRP among traffic enforcers. Moreover, the study suggests that Pb via the oxidative and inflammation pathways may have an essential role in the development of cardiovascular disease. Furthermore, MMDA and the Department of Labor and Employment can use our study's findings as evidence to conduct routine screening of blood heavy metals, especially Pb, among MMDA and other traffic enforcers as part of their yearly medical examination.

"Assessing exposure of printing factory workers in thailand to selected heavy metals using urine and hair as non-invasive matrices"

BACKGROUND

There are few thorough studies on the extent and inter-element relationships of heavy metal contamination in printing factory workers, especially in developing countries. The objective of this study was to determine the levels of eight heavy metals, including arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), cobalt (Co), lead (Pb), mercury (Hg), and manganese (Mn), in urine and scalp hair of printing industry workers, and assess inter-element correlations.

METHODS

We examined a total of 85 urine samples and 85 scalp hair samples (3 cm hair segments taken from near the scalp) in 85 printing workers from a printing house in Bangkok, Thailand. We used an interviewer-administered questionnaire about participants' printing techniques, work characteristics, and work environment. Urine and scalp hair samples were analyzed for levels of each element using the inductively coupled plasma optical emission spectrometry (ICP-OES) technique.

RESULTS

As, Cd, Cr, Ni, Pb were detected in urine with the geometric mean concentration range of 0.0028-0.0209 mg/L, and Hg, Pb, Ni, Cd, Co, Mn, Cr were detected in hair samples (0.4453-7.165 mg/kg dry weight) of printing workers. The geometric mean Ni level was significantly higher in the urine of production line workers than back-office personnel (0.0218 mg/L vs. 0.0132 mg/L; p = 0.0124). The other elements did not differ significantly between production line and back-office workers in either urine or hair. There was also a strong, statistically significant positive correlation between Ni and Co levels in hair samples of workers (r = 0.944, p < 0.0001).

CONCLUSIONS

Average concentrations of most of the metals in urine and hair of printing workers were found to be above the upper reference values. The significantly higher concentrations of Ni in production line workers might be due to more exposure to printed materials. A strong inter-element correlation between Ni and Co in hair samples can increase stronger health effects and should be further investigated. This study reveals possible dependencies and impact interactions of heavy metal exposure in printing factory workers.

The construction and validation of a lead exposure screening tool for pregnant women in Thailand (ThaiL8Is)

Objectives

To construct, validate, and implement a new screening tool for lead exposure in Thai pregnant women.

Methods

A cross-sectional study that included three processes: screening tool development, validation, and implementation. The participants were pregnant women who had received antenatal care at district health promotion hospitals. There were 100 pregnant women in Nakhon Si Thammarat province during the validation process, and 30 pregnant women in Phang Nga province during the implementation process. Blood lead levels (BLLs) were analysed by atomic absorption spectrophotometry. The sensitivity and specificity of the screening instrument, as well as the Area Under the Curve (AUC), demonstrate its validity.

Results

There were 80 BLL-related items found through the collection of primary and secondary data and examined for validity and inter-rater reliability by five experts. Six items were excluded because the values were less than the criteria set. Seventy-four items remained with the Item Content Validity Index (I-CVI) = 0.80-1.00, the Content Validity Index Average (S-CVI/Ave) = 0.91, and Kappa scores = 0.76-1.00. After using 74 items collected on pregnant women, only 31 items were included in the validation process. Following that, the pooled eight items with cut-off point scores of 1 had the highest validity, which included systolic blood pressure, diastolic blood pressure, urine sugar, haemoglobin level, occupation, drinking coffee, using chemical products, and education level (ThaiL8Is). The ThaiL8Is in the validation process yielded sensitivity = 80.9%, specificity = 69.8%, and an AUC (95%CI) = 0.78 (0.69-0.87). The implementation process has confirmed the validity of the screening tool; sensitivity = 78.9%, specificity = 81.8%, and the AUC (95%CI) = 0.80 (0.63-0.97).

Conclusions

The ThaiL8Is a valid screening tool for Thai pregnant women. ThaiL8Is' sensitivity in detecting the risk groups for lead exposure can be enhanced by a combination of biochemical markers used in routine prenatal screening. It can be used to screen pregnant women for early indicators of lead exposure prior to a blood lead test.

Evaluation of blood lead among painters of buildings and cars

Exposure to lead-based paints is a major threat to the health of painters. This study aimed to evaluate the blood concentration of lead (Pb) in painters of buildings and cars. The present study was a cross-sectional study in which a semi-structured questionnaire was used to collect the socio-demographic information. Lead concentration in blood samples was determined using the atomic absorption spectrometry method. A total of 32 male painters were selected based on inclusion criteria. The mean blood lead level (BLL) in the painters was 8.1 ± 4.93 μg/dL. Pb levels in car and building painters were 9.42 ± 5.5 μg/dL and 6.7 ± 1.85 μg/dL, respectively. Pb concentration in none of the blood samples was more than 30 μg/dL. The prevalence of BLL ≥ 5 μg/dL and BLL ≥ 10 μg/dL was 97% and 19%, respectively. According to the findings, the rate of BLL among car painters was higher than building painters. Considering the presence of Pb in all blood samples, it seems necessary to increase the awareness of painters about the adverse effects of lead exposure even in low concentrations. However, the sample size in this study was small and more investigations are required in this regard.

A systematic review of clinical and laboratory findings of lead poisoning: lessons from case reports

Lead is one of the most toxic heavy metals in the environment. The present review aimed to highlight hazardous pollution sources, management, and review symptoms of lead poisonings in various parts of the world. The present study summarized the information available from case reports and case series studies from 2009 to March 2020 on the lead pollution sources and clinical symptoms. All are along with detoxification methods in infants, children, and adults. Our literature compilation includes results from 126 studies on lead poisoning. We found that traditional medication, occupational exposure, and substance abuse are as common as previously reported sources of lead exposure for children and adults. Ayurvedic medications and gunshot wounds have been identified as the most common source of exposure in the United States. However, opium and occupational exposure to the batteries were primarily seen in Iran and India. Furthermore, neurological, gastrointestinal, and hematological disorders were the most frequently occurring symptoms in lead-poisoned patients. As for therapeutic strategies, our findings confirm the safety and efficacy of chelating agents, even for infants. Our results suggest that treatment with chelating agents combined with the prevention of environmental exposure may be an excellent strategy to reduce the rate of lead poisoning. Besides, more clinical studies and long-term follow-ups are necessary to address all questions about lead poisoning management.

The lead burden of occupational lead-exposed workers in Guangzhou, China: 2006-2019

We analyzed the lead levels in blood and urine from lead-exposed workers in Guangzhou and assessed the influencing factors. The data were analyzed by descriptive statistics, and the time-dependent changes were mapped via analytical statistics. Although the lead burden showed a clear downward trend over time, it remained high among the exposed workers. The highest lead burden was detected in workers of the electrical equipment manufacturing industry, especially among those in lead-acid battery factories where we did field studies. Hazardous as the working conditions of the original lead-acid battery factories were, there were improvements in the applications of occupational disease prevention measures after the relocation of factories, but the lead burdens were still above the average levels of lead-related industries. Improvements are needed in the management and regulations on occupational safety and health to further decrease the lead burden to acceptable levels.

Levels of lead, aluminum, and zinc in occupationally exposed workers of North-Western India

OBJECTIVES

Metals including lead (Pb), aluminum (Al), and zinc (Zn) are widely used in factories such as welding, handicrafts, and paint. Occupational exposure to such metals causes a wide range of biological effects, depending upon the metal levels and duration of exposure. Accumulation of these metals may lead to several adverse health effects such as neurodegenerative diseases and cancer. The study aimed to evaluate Pb, Al, and Zn levels in occupationally exposed workers of North-Western India and create awareness about its toxicity and adverse outcomes.

METHODS

The study included 120 factory workers (exposed) and 100 healthy controls (nonexposed); age ranged 18-78 years. Blood Pb and serum Al was estimated by graphite furnace atomic absorption spectrophotometry and serum Zn was estimated by flame atomic absorption spectrophotometry (ICE 3000, Thermo Fisher Scientific).

RESULTS

Results indicated significantly higher levels of Pb, Al, and Zn in the exposed than the nonexposed. No significant difference was observed in metal levels, based on age and duration of exposure. Painters showed higher blood Pb, whereas welders were found to have higher serum Al and Zn levels.

CONCLUSIONS

To conclude, workers showed higher levels of metals and it may cause deleterious effects on the health of workers occupationally exposed to these metals. Appropriate maintenance regarding worker's safety and hygiene is required to protect them from the harmful effects of these toxic metals.

Association between blood lead level and risk of stroke in Korean adults: a cross-sectional study in the Korea National Health and Nutrition Examination Survey 2008-2013

OBJECTIVES

Although lead is a potential risk factor for cardiovascular diseases such as stroke, research on this association in the Korean population remains limited. Therefore, we aimed to investigate the association between lead level and stroke in Korean adults.

DESIGN

A population-based cross-sectional study.

SETTING

The Korea National Health and Nutrition Examination Survey 2008-2013, which enrolled a representative sample of the Korean population.

PARTICIPANTS

We excluded participants younger than 20 years, missing weight data, pregnant or lactating, and missing blood lead and stroke data. A total of 11 510 participants were included in this analysis.

PRIMARY AND SECONDARY OUTCOME MEASUREMENT

The participants were classified by blood lead concentration into the low-level (≤2.189 µg/dL, n=5756) and high-level (>2.189 µg/dL, n=5754) groups. The main outcome, stroke, was assessed by information from physician diagnosis, prevalence of stroke or treatment for stroke. The ORs and 95% CIs were calculated to evaluate the association between blood lead level and stroke using multivariate logistic regression analysis.

RESULTS

Although blood lead level was not significantly associated with stroke (OR: 1.30, 95% CI: 0.66-2.58) in the multivariate-adjusted model, in individuals with hypertension, the high-level group was 2.36-fold higher odds of stroke (OR: 2.36, 95% CI: 1.02-5.44) compared to that in the low-level group. No association was observed in individuals with normotension (OR: 0.42, 95% CI: 0.13-1.38, p for interaction=0.007).

CONCLUSION

The association between blood lead concentration and stroke may be influenced by hypertension status. Our findings suggest the need for closer attention to lead exposure in patients with hypertension.

Blood Lead Levels among Blood Donors and High-Risk Occupational Groups in a Mining Area in Ghana: Implications for Blood Transfusion among Vulnerable Populations

Lead poisoning has been a major global health problem for decades, and blood transfusion has been suspected as a neglected potential source of lead exposure. Children and pregnant women are most vulnerable to the toxic effects of lead and over 40 percent of blood transfused in Ghana is given to children under 5 years. However, there is little data on the levels of lead in donor blood and the main sources of lead exposure in the Ghanaian population. This study compared blood lead levels (BLL) among selected occupations at risk of lead exposure with healthy blood donors in nonexposed occupations in a Ghanaian mining area. We enrolled 40 participants each from the following high-risk occupational groups: small scale miners, painters/sprayers, drivers/fuel station attendants, and auto-mechanics as well as 40 healthy blood donors (made up of teachers, traders, and office workers). One millilitre of blood was collected from each participant for determination of their BLL, haemoglobin concentration, and blood film morphology. A total of 200 participants made up of 186 (93%) males and 14 (7%) females were enrolled. The mean age of participants was 28.6 ± 8.2 years and their geometric mean (GM) BLL was 6.3 GSD 1.4 µg/dL [95% CI: 6.0 – 6.6]. Participants in high risk occupations had significantly higher GM BLL of 6.7 µg/dL [95% CI :6.4−7.0] compared to 5.0 µg/dL [95% CI: 4.4−5.7] for healthy blood donors [p < 0.001]. The prevalence of elevated BLL (≥5 µg/dL) among the entire study participants, high risk occupations and blood donors was 84.5%, 89.4% and 65% respectively. There was significant association between elevated BLLs and working in an at-risk occupational group [aOR = 3.58, p = 0.014]. Haemoglobin concentration was not significantly associated with elevated BLLs. Basophilic stippling was not observed in any of the blood smears. Blood lead levels were high in blood donors and at-risk occupations in the study area and occupation was associated with elevated BLLs. It is important that measures to safeguard the integrity of donor blood go beyond screening for infectious diseases to include screening individuals in high-risk occupations for lead and other heavy metals to ensure that donor blood from such individuals is safe and does not pose potential danger to the health of vulnerable populations such as children and pregnant women.

Nature and sources of poisoning in patients admitted to a referral hospital in Gaborone, Botswana; findings and implications

BACKGROUND

Intentional poisoning is becoming an important public health concern particularly among young women globally. Consequently, there is a need to analyze this further within countries to establish pertinent policies to reduce current incidence rates. This includes sub-Saharan African countries where there has been a scarcity of information. Consequently, we sought to establish the nature and sources of poisoning in patients admitted to a leading hospital in Botswana to help develop pertinent future policies for Botswana and surrounding countries.

METHODS

Retrospectively reviewing the medical records of all patients admitted to Princess Marina Hospital (PMH), which is a leading tertiary hospital in the capital city of Botswana, due to acute poisoning over a six-year period.

RESULTS

The records for 408 patients were reviewed. The majority of admissions (58%) were females, and the mean age of patients was 21(±14) years. Most poisoning cases (53%) were intentional. The 15-45 years age group was most likely to intentionally poison themselves compared to other age groups, with females four and half times more likely to intentionally poison themselves compared to males (AOR 4.53, 95% CI: 2.68-7.89, p < 0.001). Half of the patients were poisoned by medicines followed by household chemicals (22%), with females overall four times more likely to be poisoned by medicines compared to males. The medicine mostly ingested was paracetamol (30%). Failing relationships (57%) were the principal reason for intentional poisoning. Six patients died from poisoning representing a 1.5% mortality rate.

CONCLUSIONS

The findings suggest in-depth and urgent investigations on intentional poisoning are needed among young women across countries including sub-Saharan African countries to inform future policies on prevention strategies. Further, strategies for poisoning prevention should target social and family relationship problems. We will be following this up in the future.