Occupational lead exposure and blood pressure

Occupational lead exposure is an independent modulator of hypertension and poor pulmonary functions: A cross-sectional comparative study in lead-acid battery recycling workers

Blood lead level (BLL) is the primary biomarker for lead-exposure monitoring in occupationally exposed workers. We evaluated occupational lead-exposure (OE) impact on cardiopulmonary functions in lead-acid battery recycling unit workers. Seventy-six OE cases and 30 control subjects were enrolled for questionnaire-based socio-demographic, dietary, tobacco usage, and medical history data. Anthropometric measurements, systolic and diastolic blood pressure (SBP and DBP), and pulmonary function tests were performed. Venous blood was collected for BLL, hematological analysis, and biochemical analysis. OE caused a significant increase in BLL, SBP, DBP, and small airways obstruction in lung function tests. It also impaired platelet indices, affected renal and liver biochemical measurements, and promoted oxidative stress and DNA damage. Multilinear regression analysis suggested that BLL affected SBP (β = 0.314, p = .034) and increased small airways obstruction (FEV₁/FVC, β = -0.37, p = .05; FEV_25-75%, β = -0.351, p = .016). Higher BLL appears to be an independent modulator of hypertension and poor pulmonary function upon occupational lead exposure in lead-acid battery recyclers.

Renal function in relation to low-level environmental lead exposure

BACKGROUND

Numerous studies suggested that occupational or environmental exposure to lead adversely affects renal function. However, most studies lost relevance because of the substantially lower current environmental lead exposure and all relied on serum creatinine to estimate glomerular filtration. We investigated the association of estimated glomerular filtration rate (eGFR), estimated from serum creatinine, cystatin C or both, with blood lead (BPb) using the baseline measurements of the ongoing Study for Promotion of Health in Recycling Lead (SPHERL; NCT02243904) in newly hired workers prior to significant occupational lead exposure.

METHODS

Among 447 men (participation rate, 82.7%), we assessed the association of eGFR and the urinary albumin-to-creatinine ratio (ACR) with BPb across thirds of the BPb distribution using linear regression analysis. Fully adjusted models accounted for age, blood pressure, body mass index, the waist-to-hip ratio, smoking, the total-to-high-density-lipoprotein ratio, plasma glucose, serum γ-glutamyltransferase and antihypertensive drug treatment.

RESULTS

Age averaged 28.7 (SD, 10.2) years (range, 19.1-31.8). Geometric mean BPb concentration was 4.34 μg/dL (5th-95th percentile interval, 0.9-14.8). In unadjusted and adjusted analyses, eGFR estimated from serum creatinine [mean (SD), 105.26 (15.2) mL/min/1.73 m2], serum cystatin C [mean (SD), 127.8 (13.8) mL/min/1.73 m2] or both [mean (SD), 111.9 (14.8) mL/min/1.73 m2] was not associated with BPb (P  ≥  0.36), whereas ACR [geometric mean, 4.32 mg/g (5th-95th percentile interval, 1.91-12.50)] was lower with higher BPb.

CONCLUSIONS

At the BPb levels observed in this study, there was no evidence for an association between renal function and lead exposure.

Does low lead exposure affect blood pressure and hypertension?

Objectives

Historically, little was known about the effects of low blood lead level (BLL < 10 μg/dL) on hypertension (HTN). The purpose of this study was to assess the effects of low BLL on blood pressure (BP) and HTN in lead‐exposed male workers in the Republic of Korea.

Methods

From the year 2000 to 2004, 12,060 male workers underwent an Annual Specialised Medical Check‐up for lead; 7,341 subjects had a peak BLL < 10 μg/dL and were selected for the study. The quartiles of peak BLL in lead‐exposed workers were as follows: first (0.01‐3.68 μg/dL), second (3.69‐5.19 μg/dL), third (5.20‐6.86 μg/dL), and fourth (6.87‐10.00 μg/dL). To examine the relationship between BLL and pre‐HTN (systolic BP [SBP] ≥120‐140 mmHg; diastolic BP [DBP] ≥80‐90 mmHg) and between BLL and HTN (SBP ≥ 140 mmHg; DBP ≥ 90 mmHg), the quartiles of BLL were used as independent variables in multiple logistic regression analysis.

Results

In multiple linear regression analyses, SBP (β 0.04, P < .01) and DBP (β 0.06, P < .01) increased in line with a 1 μg/dL increase in BLL. The odds ratio (OR) of HTN in the fourth versus first BLL quartile (1.54; 95% confidence interval [CI]: 1.26, 1.89) was statistically significant.

Conclusion

SBP and DBP were statistically significantly associated with peak BLL. A BLL ≥ 6.87 μg/dL was associated with HTN; thus, even in workers with low BLLs (<10 μg/dL), management of BP is likely to be necessary. Modulation of the current safety standards for BLLs in workers will be needed.

Blood pressure and occupational exposure to noise and lead (Pb): A cross-sectional study

Several studies have explored the hypothesis that low blood lead (PbB) and high noise levels may be associated with an increased risk of hypertension. To assess the possible relationship between occupational exposure to lead (Pb) and noise and elevated blood pressure, we studied 105 workers (age: 41.27 ± 6.25 years and length of employment: 4.12 ± 5.33 years) employed in a Pb battery recycling plant by measuring A-weighted equivalent sound level, PbB, δ-aminolevulinic acid dehydratase (ALAD) activity and zinc protoporphyrin (ZPP) levels and systolic and diastolic blood pressure (SBP and DBP). Results showed that occupational exposure to higher ambient Pb and noise levels was related to slightly increased SBP and DBP. PbB values correlated significantly with SBP and DBP, whereas noise levels correlated neither with SBP nor with DBP. Furthermore, workers exposed to higher ambient Pb had higher PbB and ZPP and showed more decreased ALAD activity. Blood pressure does not correlate with noise exposure but only with PbB concentration.

Lead Nephropathy: Revisiting an Overlooked Cause of Kidney Disease

Despite the recognition of lead nephropathy as a consequence of environmental and occupational lead exposure, lead nephropathy still appears to be underrecognized by physicians as a cause and promoter of chronic kidney disease (CKD), especially in people with more apparent causative factors such as diabetes and hypertension. This review focuses on the clinical, pathophysiological and epidemiological perspectives of lead nephropathy with the objective of promoting the awareness of this important but overlooked cause of CKD among physicians. Literature was reviewed using available medical journals and online literature search through Google, Pubmed, Medline, Medscape and HINARI databases. The key words employed were: Lead Nephropathy, Environmental and Occupational lead exposure and chronic kidney disease. Lead nephropathy which is a tubulointerstitial nephritis, may present acutely or chronically in association with hypertension. The clinical diagnosis of lead nephropathy is complex, because the symptoms are varied and non-specific especially with subclinical nephrotoxicity. The recognition of lead nephropathy can be enhanced if physicians have a high index of suspicion in the assessment of patients with renal disease. It is recommended that the evaluation of environmental and occupational nephrotoxins like lead be incorporated into programs for the prevention of CKD, especially in developing countries where lead exposure and toxicity still remain largely unchecked and the prevalence and burden of CKD is increasing.

Blood lead levels and health problems of lead acid battery workers in Bangladesh

INTRODUCTION

Use of lead acid battery (LAB) in Bangladesh has risen with sharp rise of motor vehicles. As result, manufacture of LAB is increasing. Most of the lead used by these industries comes from recycling of LAB. Workers in LAB industry are at risk of exposure lead and thus development of lead toxicity.

OBJECTIVE

The objective of this study was to measure the blood lead concentration and to assess the magnitude of health problems attributable to lead toxicity among the LAB manufacturing workers.

METHODS

A cross-sectional study was conducted among the workers of LAB manufacturing industries located in Dhaka city.

RESULT

Mean blood lead level (BLL) among the workers was found to be high. They were found to be suffering from a number of illnesses attributable to lead toxicity. The common illnesses were frequent headache, numbness of the limbs, colic pain, nausea, tremor, and lead line on the gum. High BLL was also found to be related to hypertension and anemia of the workers.

CONCLUSION

High BLL and illnesses attributable to lead toxicity were prevalent amongst workers of the LAB manufacturing industries, and this requires attention especially in terms of occupational hygiene and safety.

Association between Blood Lead Level and Blood Pressure in Aborigines and Others in Central Taiwan

To investigate the relationship between the blood lead level (BLL) and blood pressure among aborigines and non-aborigines in central Taiwan, a community-based survey that included demographic data, medical history, and blood chemistry analyses was conducted among 2,565 adults during an annual health examination. BLLs were analyzed using a graphite furnace atomic absorption spectrometer (AAS). There was a dose response among the non-aborigines (high BLL odds ratio = 2.97, compared with low BLL) but not among aborigines. Based on multiple linear regression models, BLLs were positively correlated with both systolic (an increase of 0.85 mm Hg/microg/dL) and diastolic (an increase of 0.48 mm Hg/microg/dL) blood pressures after adjusting for age, gender, ethnic group, alcohol consumption, and body mass index. BLLs were higher among aborigines than non-aborigines and were significantly correlated with blood pressure, particularly systolic pressure. The association should be considered causal.

Occupational noise exposure and incident hypertension in men: a prospective cohort study

The associations between occupational noise exposure and hypertension remain controversial because of the differences in study designs, exposure assessments, and confounding controls. This prospective study investigated the relationship between noise exposure and the 10-year risk of hypertension. A cohort of 578 male workers in Taiwan was followed from 1998 to 2008. All subjects were divided into high-, intermediate-, and low-exposure groups on the basis of noise exposure assessment. Cox regression models were used to estimate the relative risks of hypertension after adjustment for potential confounders. During the 7,805 person-years of follow-up, 141 hypertension cases were identified. Significant increases of 3.2 (95% confidence interval (CI): 0.2, 6.2) mm Hg in systolic blood pressure and 2.5 (95% CI: 0.1, 4.8) mm Hg in diastolic blood pressure between the baseline and follow-up measurements were observed in the high-exposure group. Participants exposed to ≥85 A-weighted decibels (dBA) had a 1.93-fold (95% CI: 1.15, 3.22) risk of hypertension compared with those exposed to <80 dBA. There was a significant exposure-response pattern (P = 0.016) between the risk of hypertension and the stratum of noise exposure. Prolonged exposure to noise levels ≥85 dBA may increase males' systolic and diastolic blood pressure levels. This association may translate into a higher incidence of hypertension.

High-frequency hearing loss, occupational noise exposure and hypertension: a cross-sectional study in male workers

BACKGROUND

The association between occupational noise exposure and hypertension is inconsistent because of an exposure bias caused by outer-ear measurements of noise levels among workers. This study used hearing loss values (HLVs) measured at 4 kHz and 6 kHz in both ears as a biomarker to investigate the chronic effects of noise exposure on hypertension in 790 aircraft-manufacturing workers.

METHODS

Participants were divided into a high hearing loss (HL) group (n = 214; average HLVs ≥ 30 decibel [dB] at 4 kHz or 6 kHz bilaterally; 83.1 ± 4.9 A-weighted decibel [dBA]), a median HL group (n = 302; 15 ≤ average HLVs < 30 dB at 4 kHz or 6 kHz bilaterally; 83.1 ± 4.4 dBA) and a low HL group (n = 274; average HLVs < 15 dB at 4 kHz or 6 kHz bilaterally; 82.2 ± 5.1 dBA) based on the results of pure tone audiometry. Multivariate logistic regressions were used to estimate the risk of hypertension between groups.

RESULTS

The prevalence rates of hypertension were significantly higher in the high HL (43.5%; p = 0.021) and median HL (42.1%; p = 0.029) groups than in the low HL group (33.2%). The high HL and median HL workers had 1.48-fold (95% confidence interval [95%CI] = 1.02-2.15; p = 0.040) and 1.46-fold (95%CI = 1.03-2.05; p = 0.031) higher risks of hypertension relative to the low HL workers. Employment duration was significantly and positively correlated with the risk of hypertension among workers with average HLVs ≥ 15 dB at 4 kHz (p < 0.001) and 6 kHz (p < 0.001) bilaterally.

CONCLUSIONS

Our findings suggest that high-frequency hearing loss is a good biomarker of occupational noise exposure and that noise-induced hearing loss may be associated with the risk of hypertension.

Lead exposure study among workers in lead acid battery repair units of transport service enterprises, Addis Ababa, Ethiopia: a cross-sectional study

BACKGROUND

Lead exposure is common in automobile battery manufacture and repair, radiator repair, secondary smelters and welding units. Urinary Aminolevulinic acid has validity as a surrogate measure of blood lead level among workers occupationally exposed to lead. This study had therefore assessed the magnitude of lead exposure in battery repair workers of three transport service enterprises.

METHODS

To this effect, a cross-sectional study was carried out on lead exposure among storage battery repair workers between November 2004 and May 2005 from Anbasa, Comet and Walia transport service enterprises, Addis Ababa, Ethiopia. Subjective information from the workers was obtained by making use of structured questionnaire. Other information was obtained from walkthrough evaluation of the repair units. Aminolevulinic acid levels in urine were used as an index of the exposure. This was coupled to measurements of other relevant parameters in blood and urine collected from adult subjects working in the repair units as well as age matched control subjects that were not occupationally exposed to lead. Aminolevulinic acid was determined by spectrophotometry, while creatinine clearance, serum creatinine, urea and uric acid levels were determined using AMS Autolab analyzer.

RESULTS

Urinary aminolevulinic acid levels were found to be significantly higher in exposed group (16 mug/ml +/- 2.0) compared to the non-exposed ones (7 mug/ml +/- 1.0) (p < 0.001). Alcohol taking exposed subjects exhibited a significant increase in urinary aminolevulinic acid levels than non-alcohol taking ones (p < 0.05). Moreover, urinary aminolevulinic acid levels of exposed subjects increased with age (p < 0.001) as well as duration of employment (p < 0.001). Whereas serum uric acid levels of exposed subjects was significantly higher than non-exposed ones (p < 0.05), no statistically significant difference had been found in renal indices and other measured parameters between exposed and non-exposed subjects. From the questionnaire responses and walkthrough observations, it was also known that all the repair units did not implement effective preventive and control measures for workplace lead exposure.

CONCLUSION

Taken together, these findings indicated that workers in lead acid battery repair units of the transport service enterprises are not protected from possibly high lead exposure. Thus, strict enforcement of appropriate and cost effective preventive and control measures is required by all the enterprises.

Relationship of blood lead levels to blood pressure in exhaust battery storage workers

Several researches has focused the hypothesis that low blood lead levels could be associated with an increased risk of hypertension. To assess the relation between occupational lead exposure and elevated blood pressure a group of 27 workers, age range from 27 to 62 years, mean (SD) 36.52 (+/- 8.16) yr; length of employment mean (DS) 2.97 (+/- 1.67) yr, were recruited as study subjects. The following variables were measured: blood lead concentration (BPb), delta-Aminolevulinic Acid Dehydratase (ALAD) activity, Zinc Protoporphirin (ZPP), creatinine, hematocrit, Body Mass Index (BMI) and Systolic Blood Pressure (SBP) and Diastolic Blood (DBP) Pressure. The results showed that long term occupational exposure was related to a slight increase of systolic and diastolic blood pressure among workers who had been exposed to higher level of lead with respect to workers exposed to lower level of lead. Furthermore, blood lead concentration (BPb) and ZPP resulted higher among workers exposed to higher level of ambient lead, while in the same group of workers ALAD activity resulted more inhibited. The authors concluded long term cumulative lead exposure can significantly increase blood pressure in low level Pb exposed workers.

Effects of acute and chronic oval exposure of lead on blood pressure and bone mineral density in rats

The immediate and late deleterious effects of early lead (Pb) exposure on human health are major challenges to the health professionals. Therefore, a major underlying contribution of Pb accumulated earlier in life to chronic disorders such as hypertension and osteopenia, commonly found in the elderly, cannot be definitively excluded. Using Sprague-Dawley rats, we examined the effects of drinking 1% Pb acetate on very young rats for 40 days on Pb kinetics, body weight (BW), systolic blood pressure (SBP) and bone mineral density (BMD) over a year-long period. We also examined the effects of early and later chelation using disodium calcium ethylenediaminetetraacetate (Na2CaEDTA). The early ingestion and accumulation of Pb was associated with an increased SBP acutely that returned to control levels with continuing challenge and later rose above control months later after the Pb challenge had been halted. Early accumulation of Pb over a short period was also associated with decreased BMD at the end of one year. Chelation after the initial Pb challenge at various times favorably influenced the SBP but could not prevent the lowering of BMD.

Blood lead level is associated with elevated blood pressure in blacks

Chronic lead exposure has been associated with elevated blood pressure in epidemiological studies. It is not known whether the previously observed relation between blood lead and hypertension persists after significant reductions have been made in environmental lead contamination. We examined the relation between blood lead levels and blood pressure in a representative sample of 14 952 whites and blacks aged 18 years or older who participated in the Third National Health and Nutrition Examination Survey. Blood lead was measured by atomic absorption spectrophotometry and blood pressure by standard sphygmomanometry. Mean blood lead levels were significantly higher for black men and women (5.4 and 3.4 microg/dL, respectively) compared with white men and women (4.4 and 3.0 microg/dL, respectively). After multivariate adjustment for important covariables, each standard deviation higher blood lead (3.3 microg/dL) was associated with a 0.82 (95% confidence interval [CI], 0.19 to 1.44) mm Hg and a 1.55 (95% CI, 0.47 to 2.64) mm Hg higher systolic blood pressure among black men and women, respectively. In contrast, blood lead level was not associated with blood pressure among white men or women. The multivariate-adjusted odds ratio (95% CI) of hypertension associated with a 1-SD higher level of blood lead was 1.08 (95% CI, 0.99 to 1.19) for black men and 1.39 (95% CI, 1.21 to 1.61) for black women. These findings suggest that increased levels of blood lead remain an important environmental risk factor for elevated blood pressure in blacks.

Lead induced increase of blood pressure in female lead workers

AIMS

Although lead exposure has, in the absence of mathematical modelling, been believed to elevate blood pressure in females, it is necessary to clarify the relation between lead and blood pressure by eliminating confounding factors in the analysis.

METHODS

Blood lead was measured in 193 female workers, including 123 lead exposed workers. Possible confounding factors were controlled by multiple regression analyses.

RESULTS AND CONCLUSIONS

Blood lead above 40 micro g/dl was found to be the most potent factor for elevating systolic/diastolic blood pressure. Aging, urine protein, and plasma triglyceride also contributed to systolic/diastolic/pulse pressure increase, but hypertensive heredity did not. Data suggested that lead induced changes in lipoprotein metabolism may play an important role in the lead induced blood pressure increase in female workers.

Is lead exposure the principal cause of essential hypertension?

Lead is a ubiquitous toxin, known to have adverse effects on the body even at low levels of exposure. In this review we explore whether low lead may be the principal or a major contributory cause of essential hypertension, and whether removal of lead from the environment may eventually reduce both the overall incidence of hypertension and the increased incidence with aging.

Association between bone lead concentration and blood pressure among young adults

BACKGROUND

Occupational and environmental exposure to lead has been examined for its effect on blood pressure (BP) in adults with varying results. The present analyses assessed the association between bone lead concentration and BP in early adult life in persons exposed during childhood.

METHODS

Study participants included young adult members of two cohorts with different past histories of lead exposure. Lead exposure was assessed using noninvasive K-X-ray fluorescence spectroscopy to quantify bone lead concentration, an index of long-term lead exposure superior to current blood lead concentration. Systolic and diastolic BP measurements were obtained using conventional clinical methods. Multiple linear regression models were constructed to allow for control of covariates of BP identified a priori.

RESULTS

Analyses were performed on 508 participants. While controlling for potential confounders, systolic BP was 4.3 mm Hg greater among members of the highest of four bone lead concentration groups (> 10 microg Pb/g bone) when compared with the lowest bone lead concentration group (< 1 microg Pb/g bone; P = 0.004), and diastolic BP was 2.8 mm Hg greater among members of the highest bone lead concentration group when compared with the lowest bone lead concentration group (P = 0.03).

CONCLUSIONS

These results suggest that substantial lead exposure during childhood can increase BP during young adulthood.

An epidemiological re-appraisal of the association between blood pressure and blood lead: a meta-analysis

Studies on the possible association between blood pressure and blood lead have reached divergent conclusions. In a previous meta-analysis, a doubling of the blood lead concentration was associated with a 1.0/0.6 mm Hg increase in systolic and diastolic blood pressure (BP). This meta-analysis updates the analysis originally performed in 1994. Articles on the association between BP and blood lead were identified from computer searches from January 1980 to February 2001 using the Medical Literature Analysis and Retrieval System. Of the studies reviewed, 31 provided sufficient details to be considered. The meta-analysis included 58518 subjects recruited from the general population in 19 surveys and from occupationally exposed groups in 12 studies. In all but four studies, the results were adjusted for age, and most studies took into account additional confounding factors such as body mass index and the use of alcohol and medication. Weighted joint P-values were calculated using Stouffer's procedure. The association between BP and blood lead was similar in both men and women. In the combined studies, a two-fold increase in blood lead concentration was associated with a 1.0 mm Hg rise in the systolic pressure (95% CI +0.5 to +1.4 mm Hg; P < 0.001) and with a 0.6 mm Hg increase in the diastolic pressure (95% CI +0.4 to +0.8 mm Hg; P < 0.001). On balance, this meta-analysis suggests that there can only be a weak association between BP and blood lead.

A pilot survey of blood lead levels in various types of workers in the United Arab Emirates

The aim of the present study is to determine the effect of blood lead on the health of industrial workers in United Arab Emirates (UAE). This is a cross-sectional pilot survey of blood lead levels (BLL) of 100 industrial workers (exposed) and 100 non-industrial workers (nonexposed), matched for age, sex and nationality selected from Al-Ain, Abu-Dhabi Emirate. Industrial workers had significantly higher mean of BLL (77.5+/-42.8 microg/dl and median 80.9 microg/dl) than non-industrial workers (19.8+/-12.3 microg/dl and median 11.0 microg/dl). In the present study, reported symptoms among industrial workers were strongly associated with BLL nausea/vomiting, muscular symptoms, dizziness, fatigue, irritability, memory disturbances, insomnia and allergic conjuctivitis, rhinitis and dermatitis. Furthermore, the present study revealed that industrial workers had higher prevalence of respiratory symptoms for phlegm, shortness of breath and diagnosed asthma. In conclusion, this study determined that occurrence of certain symptoms might be associated with lead exposure among industrial workers.

Blood pressure, left ventricular mass, and lead exposure in battery manufacturing workers

BACKGROUND

Although debate about the relationship between lead and blood pressure has focused on low environmental lead levels, industrial exposure remains a concern.

METHODS

We measured blood pressure and left ventricular mass (LVM) in 108 battery manufacturing workers, and calculated cumulative and historic average measures of blood lead.

RESULTS

Diastolic pressure increased with increasing lead levels, with a significant (P = 0.04) 5 mmHg difference in mean pressure between the highest and lowest cumulative exposure levels. Diastolic pressure increased with the log of cumulative lead (P = 0.06). Both hypertension (defined as currently medicated or systolic > 160 mmHg or diastolic > 95 mmHg) and LVM increased nonsignificantly with increasing lead exposure (P-values > or = 0.17 for hypertension and > or = 0.20 for LVM).

CONCLUSIONS

We found a small effect of blood lead on diastolic blood pressure, particularly for a cumulative measure of exposure, but no convincing evidence of associations between lead and other blood-pressure-related outcomes. Published 2001 Wiley-Liss, Inc.

Transient but not sustained blood pressure increments by occupational noise. An ambulatory blood pressure measurement study

OBJECTIVE

Studies on the effects of chronic exposure to industrial noise on clinic blood pressure (BP) at rest have yielded inconsistent results. The aim of this study was to evaluate the effect of occupational noise exposure on ambulatory blood pressure (ABP) in normotensive subjects.

METHODS

We studied 476 normotensive workers, aged 20-50 years (systolic blood pressure (SBP) < 140, diastolic blood pressure (DBP) < 90), at a metallurgical factory; 238 were exposed to high levels of noise (> 85 dB), while 238 were not exposed (< 80 dB). Clinical evaluation included measurements of casual BP (by standard mercury sphygmomanometer, Korotkoff sound phase I and V) and heart rate (HR) (by pulse palpation), body height and weight. All subjects underwent a 24 h non-invasive ABP monitoring (by SpaceLabs 90207 recorder; SpaceLabs, Redmond, Washington, USA) twice within 14 days: one during a normal working day and one during a non-working day. Measurements were performed every 15 min. Computed analysis of individual recordings provided average SBP, DBP and HR values for 24 h, daytime working hours (0800-1700 h), daytime non-working hours (1700-2300 h) and night-time (2300-0800 h).

RESULTS

No significant difference in clinic SBP, DBP and HR was observed between exposed and non-exposed subjects. Results obtained by ABP monitoring showed in the exposed workers: (a) a higher SBP (by a mean of 6 mmHg, P < 0.0001 versus controls) and DBP (by a mean of 3 mmHg, P < 0.0001) during the time of exposure and the following 2 or 3 h, whereas no difference between the two groups was found during the non-working day; (b) an increase in HR, which was present not only during the time of exposure to noise (+3.7 beats-per-minute (bpm), P < 0.0001 versus controls), but also during the non-working hours (+2.8 bpm, P < 0.001) and during the day-time hours of the non-working day (+2.8 bpm, P < 0.003); (c) a significant increase in BP variability throughout the working day.

CONCLUSIONS

These findings suggest that in normotensive subjects below the age of 50 years, chronic exposure to occupational noise is associated with a transient increase in BP, which is not reflected in a sustained BP elevation. The possible role of repeated BP and HR fluctuations due to frequent and prolonged exposure to noise in accounting for the higher prevalence of hypertension reported in noise-exposed workers above age 50 years, requires longitudinal studies to be clarified.

Occupational lead exposure and amino acid profiles and liver function tests in industrial workers

The aim of the present study is to determine the effect of blood lead on the plasma levels of amino acids and serum liver enzymes in industrial workers in United Arab Emirates (UAE). This comparison study consisted of 100 industrial workers (exposed) and 100 non-industrial workers (non-exposed), matched for age, sex and nationality selected from Al-Ain, Abu-Dhabi Emirates. Industrial workers had higher proportion (19%) of smokers than non-industrial workers (11%) which was not considered to be statistically significantly different. Industrial workers had significantly higher mean of blood lead level (77.5 +/- 42.8 miccrog x dl(-1)) than non-industrial workers (19.8 +/- 12.3 microg x dl(-1)). The amino acid analysis showed higher values among industrial than non-industrial workers for histidine, isoleucine, leucine, threonine, lysine, valine, methionine and arginine (essential amino acids, (p<0.0001). Ornithine, taurine, glutamic acid, serine, glycine, proline and alanine (non-essential amino acids) showed significantly higher values in industrial when compared with the non-industrial workers (p<0.0001). Plasma liver function test, cardiac enzymes and renal function test were carried out on industrial and non-industrial workers. The results revealed alkaline phosphatase (p=0.012) and lactate dehydrogenase (p=0.029) were significantly higher in industrial than in non-industrial workers. On the basis of this study, it can be concluded that a substantial difference in amino acid profiles, blood lead and LFT between exposed and non-exposed was found. These results might be related to lead exposure and might have affects on the kidneys or liver.

Air pollution and health in urban areas

In this paper, recent reviews of the World Health Organization, other review papers, and more recent literature on the human health effects of current air pollution trends in urban areas are reviewed and summarized as follows: Sulphur dioxide. Some studies, but not others, found associations between sulphur dioxide (SO2) exposure and daily mortality and morbidity. Single-pollutant correlations sometimes disappeared when other pollutants, especially suspended particulate matter (SPM), were included. Cross-sectional studies with asthmatics revealed significant, non-threshold relations between SO2 and decrements of the forced expiratory volume in 1 second (FEV1). Nitrogen dioxide. Weak associations between short-term nitrogen dioxide (NO2) exposure from gas cooking and respiratory symptoms and a decrement in lung function parameters were found in children, but not consistently in exposed women. With long-term exposure, children, but not adults, exhibit increased respiratory symptoms, decreased lung function, and increased incidences of chronic cough, bronchitis, and conjunctivitis. A causal relationship between NO2 exposure and adverse health effects has not yet been established. Carbon monoxide. Binding of CO in the lungs with hemoglobin in the blood forms carboxyhemoglobin (COHb), which impairs the transport of oxygen. The health effects of CO include hypoxia, neurological deficits and neurobehavioral changes, and increases in daily mortality and hospital admissions for cardiovascular diseases. The latter persists even at very low CO levels, indicating no threshold for the onset of these effects. Whether the relation between daily mortality and exposure to CO are causal or whether CO might act as a proxy for SPM is still an open question. Ambient CO may have even more serious health consequences than does COHb formation and at lower levels than that mediated through elevated COHb levels. Ozone. Short-term acute effects of O3 include pulmonary function decrements, increased airway responsiveness and airway inflammation, aggravation of pre-existing respiratory diseases like asthma, increases in daily hospital admissions and emergency department visits for respiratory causes, and excess mortality. Exposure-response relations are non-linear for the respective associations between O3 and FEV1, inflammatory changes, and changes in hospital admissions, whereas the relation between percent change in symptom exacerbation among adults and asthmatics is linear. Single-pollutant associations between O3 exposure and daily mortality and hospital admissions for respiratory diseases is statistically significant, even in multi-pollutant models. Suspended particulate matter. Associations between SPM concentrations and mortality and morbidity rates are significant. The acute health effects of SPM, even at short-term low levels of exposure, include increased daily mortality and hospital admission rates for exacerbation of respiratory disease, fluctuations in the prevalence of bronchodilator use, and cough and peak flow reductions, as well as long-term effects with respect to mortality and respiratory morbidity. Such effects depend on particle size and concentration and can fluctuate with daily fluctuations in PM10 or PM2.5 levels. The relation between PM10 or PM2.5 exposure and acute health effects is linear at concentrations below 100 micrograms/m3. Currently no threshold has been reported below which no effects occur. The influence of co-polluting gaseous pollutants could explain part of the observed variance in short-term health effects and reduce the contribution of SPM. Lead. The biological effects of lead can be related to blood lead levels, the best indicator of internal exposure. The potential effects of lead in adults and children include encephalopathic signs and symptoms, central nervous system symptoms, cognitive effects, increased blood pressure, and reduced measures of child intelligence. (ABSTRACT TRUNCATED)

Clinical evaluation and management of lead-exposed construction workers

An estimated one million construction workers are currently occupationally exposed to lead. Until 1993, construction workers were not offered the protections of OSHA's 1978 standard for lead exposure in industrial activities. Preventing exposure to lead in the construction setting presents many challenges, given the rapidly and frequently changing work environment. This article reviews the adverse effects of lead on human health and presents an approach to the diagnosis, management, and prevention of lead-related illness. The medical aspects of the 1993 OSHA standard for lead in construction are described.

Reappraisal of the relation between blood lead concentration and blood pressure among the general population in Taiwan

OBJECTIVES

The relation between blood lead concentration (PbB) and blood pressure was examined in a Taiwan nationwide population survey of PbB from July 1993 to June 1994.

METHODS

After multistage sampling procedures, 2800 subjects (1471 males and 1329 females) with a mean (range) age of 44 (15-85) years were enrolled in this study. Anthropometric, blood pressure, and lifestyle factors were measured during household visits. The PbB was measured with a flameless atomic absorption spectrophotometer and all specimens were analysed in triplicate.

RESULTS

The mean (range) PbB among all study subjects was 6.5 (0.1-69.1) micrograms/dl; among males it was 7.3 (0.1-69.1) micrograms/dl and among females 5.7 (0.1-40.1) micrograms/dl). The mean (range) systolic blood pressure among all subjects was 123 (80-210) mm Hg, among males it was 127 (80-200) mm Hg and among females 119 (80-210) mm Hg. The diastolic blood pressure among all subjects was 78 (40-150) mm Hg; among males it was 80 (40-130) mm Hg; and among females 75 (40-150) mm Hg. Age, body height, body weight, and body mass index (BMI) were significantly correlated with systolic blood pressure or diastolic blood pressure in both sexes. The PbB (or the natural logarithmic transformed PbB) was not significantly correlated with blood pressure among males or females. After adjustment for the potential confounders of age, age2, BMI, milk intake, alcohol consumption, and cigarette smoking, systolic blood pressure was significantly associated with PbB among males with a regression coefficient (beta) of 0.185 (p = 0.015). No significant association between PbB and blood pressure was found among females.

CONCLUSIONS

From this study, only a weak association between systolic blood pressure and PbB was found among males. There was no strong evidence that PbB was a good predictor of blood pressure. However, the possibility that long term high body lead burden could cause high blood pressure could not be ruled out on the basis of this survey.