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Effects of the Decrease in Blood Lead Levels on
Renal and Neurological Functions Among
Occupationally Exposed and Unexposed
Populations of South India: A Cohort Study
Arti Gupta , Mukesh Tripathi , Bari Siddiqui MA , Desai V. Sripad , Vamsikrishna Reddy K ,
Desu Rama Mohan , Prudhvinath A. Reddy , Rakesh Upparakadiyala
1. Department of Community and Family Medicine, All India Institute of Medical Sciences, Mangalagiri, IND 2.
Department of Anesthesiology, All India Institute of Medical Sciences, Mangalagiri, IND 3. Department of
Biochemistry, All India Institute of Medical Sciences, Mangalagiri, IND 4. Department of Hospital Administration, All
India Institute of Medical Sciences, Mangalagiri, IND 5. Department of Radiodiagnosis, All India Institute of Medical
Sciences, Mangalagiri, IND 6. Department of General Medicine, All India Institute of Medical Sciences, Mangalagiri,
IND
Corresponding author: Arti Gupta, guptaarti2003@gmail.com
Abstract
Introduction: Exposure to lead in excess of the permissible limit is a known risk factor leading to preventable
morbidity. The present study aimed to assess whether there is a change in the neurological and renal
parameters among adults with blood lead levels (BLLs) higher than recommended at baseline and after
prevention among differently exposed adults.
Methodology: In the Guntur District of Andhra Pradesh, India, a cohort study was carried out in 2022-2023
among 180 adult males and females aged 20 to 60 years in three groups: direct occupational exposure,
indirect occupational exposure, and no occupational exposure. If the blood levels were more than or equal to
5 mcg/dL, the participant's detailed neurological examination was done at baseline and end of follow-up.
During the six-month follow-up period, health education on lead awareness was given monthly. BLLs were
estimated using graphite furnace atomic absorption spectrometry (GFAAS). Serum creatinine was estimated
using Jaffe's modified method. On neurological examination, reflexes, power, and sensation were assessed.
The vibration perception threshold was determined using a biothesiometer. A p-value less than 0.05 was
considered to be statistically significant.
Results: Among the 180 participants, the mean BLLs at baseline were 7.15±3.06 mcg/dL. The findings
revealed a statistically significant decrease in mean BLLs at baseline to end of six-month follow-up. Despite
this improvement, participants with BLLs ≥5 mcg/dL still accounted for a considerable proportion, albeit
reduced, particularly in Groups 1 and 2. There were no statistically significant changes observed in the
proportions of participants with abnormal serum creatinine, anemia, or abnormal neurological parameters.
Conclusion: These results suggest that while prevention activities may effectively reduce overall BLLs, there
might be challenges in completely mitigating the impact on certain health parameters, such as renal and
neurological functions.
Categories: Preventive Medicine, Public Health, Occupational Health
Keywords: anemia, neurological, renal, occupation, lead
Introduction
The Centers for Disease Control and Prevention (CDC) updated the blood lead reference value from 5 mcg/dL
to 3.5 mcg/dL in October 2021 [1]. In India, there are no specific national regulations regarding blood lead
levels (BLLs) in factory workers and the general population. However, the Occupational Safety and Health
Administration (OSHA) in the United States has established regulations for lead exposure. However, OSHA's
general industry and construction lead standards include a medical removal protection provision for workers
whose BLLs reach or exceed 50 mcg/dL (construction) or 60 mcg/dL (general industry) [2].
The US OSHA standard for lead exposure is followed by the Factory Act in India, allowing people to continue
working in a lead-exposed environment with BLLs up to 40 mcg/dL [3]. However, studies have documented
that the neurotoxic effects of lead in workers can be induced at BLLs below 18 mcg/dL [4]. Many longitudinal
studies have provided evidence that cumulative lead doses cause cognitive dysfunction. The majority of
these studies are among children, pregnant women, and occupationally exposed workers [4-6]. Once lead is
absorbed into the bloodstream, some of it is filtered out and excreted, but the rest gets distributed to the
liver, brain, kidneys, and bones. Lead causes anemia in adults by impairing the formation of oxygen-carrying
molecules, beginning at exposures of around 40 mcg/dL [7].
1 2 3 3 4
4 5 6
Open Access Original
Article DOI: 10.7759/cureus.54432
How to cite this article
Gupta A, Tripathi M, Siddiqui MA B, et al. (February 18, 2024) Effects of the Decrease in Blood Lead Levels on Renal and Neurological Functions
Among Occupationally Exposed and Unexposed Populations of South India: A Cohort Study. Cureus 16(2): e54432. DOI 10.7759/cureus.54432
We hypothesize that the neurological and renal manifestations are present even after BLLs return to normal.
The OSHA acceptable criteria for considering lead toxicity in the Indian population is much higher, leading
to an irreversible neurological deficit that is preventable. This study aimed to assess whether there is a
change in the neurological and renal parameters among adults with BLLs higher than recommended at
baseline and after prevention among differently exposed adults.
Materials And Methods
In the Guntur District of Andhra Pradesh, India, a cohort study was carried out in 2022-2023 among adult
males and females aged 20 to 60 years in an area around 30 km surrounding All India Institute of Medical
Sciences, Mangalagiri. Three groups of people were recruited to participate in the study: Group 1: direct
occupational exposure (lead smelters, smolders, painters, construction workers, demolition workers, and gas
station attendants); Group 2: indirect air pollution (traffic police, police, truck, bus, auto, and petrol bunk
workers); and Group 3: not directly involved in the lead exposed occupation (indoor officer workers,
teachers, primary healthcare providers, and housewives). Participants were eligible to participate if they
were residents of the area for at least the last six months and members of Group 3, Group 1, and Group 2
who had been employed in the same profession for at least six months. Those who declined consent, had
diabetes mellitus, hypertension, or surgery, or exhibited signs suggestive of a serious condition were
excluded. The study was approved by the Ethics Committee of All India Institute of Medical Sciences
Mangalagiri (approval number: AIIMS/MG/IEC/2022-23/13, approval date: 23-03-2022).
Using a t-test to compare the means of continuous variables, the sample size was determined using the
calculation:
n= {(σ12 + σ22) * [Z1-@/2 + Z 1- β]2}/(M1-M2)2
where σ1 is the SD of the outcome variable in Group 1, σ2 is the SD of the outcome variable in Group 2, and
M1-M2 is the mean difference to be detected.
Group 1 consists of laborers who handle raw materials in a battery industry located in Nellore, Andhra
Pradesh. Their BLLs (mcg/dL) was 26.2±2.142 in 2016-2017 [3]. Group 2 comprises lead-exposed healthy
school teachers who do not work in the public or government sector of Jodhpur and have BLLs (mcg/dL) of
6.89±9.5 [8]. For any two groups, a sample size of 60 was needed to detect a 3.0 mcg/dL difference in BLLs,
with 80% power and 95% confidence intervals [9]. A total of 180 individuals were studied.
Information about the study was shared with communities via field health workers, schools, Anganwadi, and
social media. They were to be a liaison participant for us in their routine field visit and brief us about the
study. Any eligible participants in each of the three groups in the communities with the willingness to
participate in the study were enrolled. Independent teams of investigators for coding and assessing exposure
to lead, checklist-based clinical assessment, interviews, and blood sampling were formed. The investigator
introduced himself/herself to the participant before the start of the interview. Individuals were given patient
information sheets and were explained regarding the study, its objectives, procedure, and the rights of the
participants. If the individuals agreed to participate in the study after going through the information sheet,
then informed written consent was obtained from them. A unique code was given to the participant. The
participants were interviewed according to the interview schedule. A blood sample for lead, hemoglobin, and
serum creatinine estimation was done after the interview. Clinicians, laboratory technicians, and data
analysts were blinded. The blood samples were transported to the laboratory, maintaining the cold chain.
If the BLL is <5 mcg/dL, the participant was retested for BLLs after six months. If the blood levels were ≥5
mcg/dL, the participants had a detailed neurological examination. They were retested for BLLs and
neurological examination after six months. A structured data collection instrument comprising information
about socio-demographic details, including age, smoking status, alcohol ingestion, and clinical details, was
developed. This was pretested, suitably modified, and then implemented.
BLLs were estimated using a graphite furnace atomic absorption spectrophotometer (GFAAS) [10]. The
method is validated, has a good detection limit (<1-2 mcg/dL), requires a small sample size, has a
multielement capacity, and has very few interferences. Serum creatinine was estimated on a Beckman
Coulter 700 AU (Beckman Coulter, Inc., CA, USA) using Jaffe’s modified method [11]. The normal range for
serum creatinine levels was considered to be 0.74 to 1.35 mg/dL for adult males and 0.59 to 1.04 mg/dL for
adult females. Hemoglobin was tested using the analyzer. Anemia was defined as hemoglobin <12 gm/dL
among adult females and <13 gm/dL among adult males. On neurological examination, reflexes, power, and
sensation were assessed. The vibration perception threshold (VPT) was determined using biothesiometry.
Those with an average VPT of ≥15 V were considered abnormal. During the six-month follow-up period,
health education on lead awareness was given every month through handouts or WhatsApp in a similar
pattern in all three groups (Figure 1).
2024 Gupta et al. Cureus 16(2): e54432. DOI 10.7759/cureus.54432 2 of 11
FIGURE 1: Flow diagram of study participants
BLL: blood lead level
Data were entered into Microsoft Excel (Microsoft Corporation, WA, USA) and analyzed using SPSS Statistics
version 28.0 (IBM Corp. Released 2021. IBM SPSS Statistics for Windows, Version 28.0. Armonk, NY: IBM
Corp.). Lead exposures at baseline were categorized into three groups. The data were expressed as frequency,
proportion, and mean ± SD. A one-way ANOVA was used to check the significance between various
explanatory variables and BLLs among different groups. We defined statistical significance as p<0.05. The
two-sample z-test for proportions was used to compare significant changes in proportions at baseline and
end of follow-up surveys for abnormal serum creatinine, neuro-examination, and anemia. A paired t-test
was used to compare significant changes in the mean of biochemical parameters at baseline and end of
follow-up. A p-value less than 0.05 was considered to be statistically significant.
Results
A total of 180 participants were studied at baseline. After the six-month follow-up period, 162 participants
could be studied with an attrition rate of 10% due to death, illness, and withdrawal of participation. Of the
total, 134 (74.4%) were males. Nearly two-thirds of participants were less than 40 years of age, 118 (65.6%),
2024 Gupta et al. Cureus 16(2): e54432. DOI 10.7759/cureus.54432 3 of 11
and educated to ≥10 standards, 123 (68.3%). The majority of the participants belonged to the upper middle
85 (47.2%) or middle 43 (23.9%) socioeconomic status. Males had significantly higher BLLs in all three
groups compared to females (p<0.005). BLLs were also significantly higher among the three groups of low
socioeconomic status and low alcohol use (Table 1).
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Domain Category
N % Group 1 Group 2 Group 3 F
statistics p-value
Mean SD Mean SD Mean SD
Age (in years)
<40 118 65.6 9.12 2.57 7.54 2.64 5.63 2.9
1.05 0.31
≥40 62 34.4 7.98 2.07 7.05 3.53 5.95 3.15
Gender
Female 46 25.6 0.00 0 5.10 0.42 5.71 3.09
16.26 <0.005*
Male 134 74.4 8.50 2.36 7.41 3.04 5.48 2.42
Education
<10 standard 57 31.7 8.47 2.62 7.65 2.06 4.55 1.3
2.08 0.15
≥10 standard 123 68.3 8.51 2.13 7.18 3.42 5.82 3.05
Migrant
Yes 43 23.89 8.78 2.68 6.80 2.5 6.90 4.13
0.01 0.91
No 137 76.11 8.45 2.33 7.58 3.23 5.19 2.2
Living with family
Yes 171 95.0 8.46 2.25 7.30 3.08 5.67 2.94
0.41 0.52
No 9 5.0 9.02 4.03 7.96 1.73 5.05 2.33
Socioeconomic status using
BG prasad
Upper (INR 7889 and
above) 45 25.00 6.90 1.44 6.18 2.63 5.64 2.81
4.83 0.003*
Upper middle (INR
3944-7888) 85 47.22 8.36 2.25 8.00 3.59 5.26 2.33
Middle (INR 2367-3943) 43 23.89 9.35 2.17 8.36 1.94 6.72 4.39
Lower middle (INR
1183-2366) 7 3.89 7.22 3.39 7.50 0 5.80 0
Smoking
Yes 32 17.78 9.35 2.59 7.39 2.58 0.00 0
4.64 0.03*
No 148 82.22 8.26 2.26 7.31 3.23 5.65 2.91
Smokeless tobacco use
Yes 7 3.89 8.92 2.98 0 0 0 0
2.53 0.11
No 173 96.11 8.44 2.29 7.34 3.02 5.65 2.91
Alcohol use
Yes 49 27.22 9.08 2.4 8.15 3.45 0 0
16.13 <0.001*
No 131 72.78 8.16 2.29 6.67 2.48 5.65 2.91
Area of living
Rural 75 41.6 8.61 2.39 7.88 2.69 5.18 2.65
0.93 0.39Urban 47 26.11 7.40 4.57 7.07 3.41 5.53 1.98
Peri-urban 58 32.22 8.50 2.14 6.60 1.88 6.25 3.58
Drinking water source
RO 25 13.89 9.20 5.48 2.42 5.33 3.02
3.72 0.01*
Canned water 91 50.56 8.39 2.41 7.63 3.08 5.97 2.56
Municipality 50 27.78 8.67 1.58 7.62 3.21 6.02 3.71
Others 14 7.78 8.66 5.7 7.52 2.28 4.57 1.68
Total 8.50 2.36 7.34 3.02 5.73 2.92 15.91 <0.001*
TABLE 1: Comparison of BLLs among the three studied groups by various factors at baseline
(n=180)
BLLs: blood lead levels
*p<0.05 was considered statistically significant
There was a statistically significant decrease in mean BLLs at baseline (7.15±3.06 mcg/dL) and end of six-
month follow-up (5.89±3.35 mcg/dL) with p<0.001. There was also a statistically significant decrease in
2024 Gupta et al. Cureus 16(2): e54432. DOI 10.7759/cureus.54432 5 of 11
hemoglobin at baseline (13.89±2.18 g/dL) and end of six-month follow-up (13.62±2.17 g/dL) with p<0.001
(Table 2).
Biochemical parameter
Baseline (n=162) After six-month follow-up (n=162)
t p-value
Mean SD Mean SD
Blood lead (mcg/dL) 7.15 3.06 5.89 3.35 6.50 <0.001*
Serum creatinine 0.75 0.21 1.60 7.34 -1.46 0.15
Haemoglobin (gm/dL) 13.89 2.13 13.62 2.17 3.19 <0.001*
TABLE 2: Summary of biochemical parameters at baseline and end of six-month follow-up survey
*p<0.05 was considered statistically significant
The proportion of BLLs ≥5 mcg/dL significantly decreased from 72.2% to 50.6% among participants (n=162)
at baseline and end of follow-up surveys, respectively. On further stratification of participants into
occupation groups, the proportion of BLLs ≥5 mcg/dL among Group 1 significantly dropped from 92.3%
(95%CI: 85.1 to 99.5) to 67.3% (95%CI: 54.5 to 80.0) at baseline and the end of follow-up surveys among
participants (p=0.001). In addition, the proportion of BLLs ≥5 mcg/dL among Group 2 also significantly
dropped from 75.9% (95%CI: 64.4 to 87.3) to 53.7% (95%CI: 40.4 to 67.0) at baseline and end of follow-up
surveys among participants (p=0.015) (Table 3).
Domain
Participants with blood levels more than or equal to 5
mcg/dL
z-
test p-value
Total Baseline survey End survey
n n % (95% CI) n % (95% CI)
Step 1: number of participants excluding
attrition 162 117 72.2 65.1-78.9 82 50.6 42.3-57.7 4.1 <0.0001*
Step 2: stratifying participants for occupation
Group 1 52 48 92.3 85.1-99.5 35 67.3 54.5-80.0 3.2 0.0015*
Group 2 54 41 75.9 64.4-87.3 29 53.7 40.4-67.0 2.4 0.0157*
Group 3 56 27 48.2 35.1-61.2 18 32.1 19.9-44.3 1.7 0.0822
TABLE 3: Comparison of proportion of BLLs more than or equal to 5 mcg/dL at baseline and end
of six-month follow-up survey
BLLs: blood lead levels
*p<0.05 was considered statistically significant
There was no statistically significant change using the z-test for proportion among participants with
abnormal serum creatinine at baseline and end of follow-up surveys and with stratification by occupation
and BLLs (Table 4).
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Domain
Participants with abnormal serum creatinine
z-test p-valueTotal Baseline survey End survey
n n % (95% CI) n % (95% CI)
Step 1: participants excluding attrition 162 62 38.3 30.81-45.8 69 42.6 35-50.2 0.8 0.4304
Step 2: stratifying participants with respect to occupation
Group 1 52 19 36.5 23.41-59.5 20 38.5 25.2-51.7 0.2 0.8332
Group 2 54 18 33.3 20.7-45.9 17 31.5 19.1-43.9 0.2 0.8416
Group 3 56 25 44.6 31.5-57.6 32 57.1 44.1-70.0 1.3 0.1858
Step 3: stratifying participants with respect to BLLs
Group 1: BLL <5 mcg/dL 4 2 50 01.00-99.0 2 50 01.0-99.0 0 1
Group 1: BLL ≥5 mcg/dL 48 17 35.4 21.9-49.0 18 37.5 23.8-51.2 0.2 0.8307
Group 2: BLL <5 mcg/dL 13 2 15.4 -04.22-35.0 4 30.8 05.7-55.9 0.9 0.3516
Group 2: BLL ≥5 mcg/dL 41 16 39 24.0-54.0 13 31.7 17.4-46.0 0.7 0.4893
Group 3: BLL <5 mcg/dL 29 11 37.9 20.2-55.5 18 62.1 44.4-79.7 1.8 0.0653
Group 3: BLL ≥5 mcg/dL 27 14 51.9 33.0-70.7 14 51.9 33.0-70.7 0 1
TABLE 4: Comparison of proportion of abnormal serum creatinine at baseline and end of six-
month follow-up survey
BLL: blood lead level
*p<0.05 was considered statistically significant
There was no statistically significant change using the z-test for the proportion among participants with
anemia at baseline and end of follow-up surveys, with stratification by occupation and BLLs (Table 5).
2024 Gupta et al. Cureus 16(2): e54432. DOI 10.7759/cureus.54432 7 of 11
Domain
Participants with anemia
z-test p-valueTotal Baseline survey End survey
n N % (95% CI) n % (95% CI)
Step 1: participants excluding attrition 162 135 83.3 77.56-89.0 128 79 72.7-85.2 1 0.3224
Step 2: stratifying participants for occupation
Group 1 52 51 98.1 94.3-101.8 50 96.2 91.0-101.4 0.6 0.5604
Group 2 54 51 94.4 88.2-100.5 51 94.4 88.2-100.5 0 1
Group 3 56 33 58.9 46.0-71.7 27 48.2 1.1 0.2563
Step 3: stratifying participants for BLLs
Group 1: BLL <5 mcg/dL 4 4 100 -19.4-39.4 4 100 -19.4-39.4 0 1
Group 1: BLL ≥5 mcg/dL 48 47 97.9 93.8-101.9 46 95.8 90.1-101.4 0.6 0.5559
Group 2: BLL <5 mcg/dL 13 12 92.3 77.8-106.7 12 92.3 77.8-106.7 0 1
Group 2: BLL ≥5 mcg/dL 41 39 95.1 88.4-101.7 39 95.1 88.4-101.7 0 1
Group 3: BLL <5 mcg/dL 29 17 58.6 40.6-76.5 14 48.3 30.1-66.4 0.8 0.4317
Group 3: BLL ≥5 mcg/dL 27 16 59.3 40.7-77.8 13 48.1 29.2-67.0 0.8 0.4092
TABLE 5: Comparison of proportion of anemia at baseline and end of six-month follow-up survey
BLL: blood lead level
There was no statistically significant change using the z-test for proportion among participants with BLLs
≥5 mcg/dL with abnormal VPT, abnormal reflexes, and abnormal muscle power at baseline and end of
follow-up surveys and with stratification by occupation (Table 6).
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Participants with VPT ≥15 V
Domain
Total Baseline survey End survey
z-test p-value
n n % (95% CI) n % (95% CI)
Step 1: participants excluding attrition 116 25 21.6 14.11-29.0 15 12.9 6.8-19.0 1.8 0.0795
Step 2: stratifying participants with respect to occupation
Group 1 48 10 20.8 09.3-32.3 8 16.7 6.15-27.2 0.5 0.6068
Group 2 41 11 26.8 13.2-40.3 6 14.6 3.7-25.4 1.4 0.1728
Group 3 27 4 14.8 1.4-28.1 1 3.7 18.7-55.2 1.9 0.0626
Participants with any abnormal reflex
Step 1: participants excluding attrition 116 24 20.7 13.3-28.0 20 17.2 10.3-24.0 0.7 0.4964
Group 1 48 9 18.8 7.7-29.8 5 10.4 1.7-19.0 1.2 0.2439
Group 2 41 8 19.5 7.7-31.6 7 17.1 5.5-28.6 0.3 0.7787
Group 3 27 7 29.5 12.3-46.7 8 29.6 12.3-46.8 0 0.9936
Participants with power 3 or less in any muscle
Step 1: participants excluding attrition 116 3 2.6 18.0-33.9 10 8.6 79.6-92.3 9.2 0
Group 1 48 1 21.1 95.6-32.6 7 14.6 4.6-24.5 0.8 0.4057
Group 2 41 2 4.9 33.7-64.3 2 4.9 33.7-64.3 0 1
Group 3 27 0 0 0 1 3.7 18.7-55.2 3.5 0.0005
TABLE 6: Comparison of proportion of abnormal neurology examination at baseline and end of
six-month follow-up survey
Discussion
The present study is a first-of-its-kind community-based cohort study in India that studied whether any
changes occur in neurological and renal parameters in adults with elevated BLLs at baseline and after
prevention for six months. The study's assessment of the overall mean BLLs at baseline, averaging 7.15±3.06
mcg/dL, reveals a concerning elevation compared to the recently updated blood lead reference value by the
CDC [1]. The stratification of the participants into three distinct groups based on occupational exposure
provides valuable insights into the varying degrees of BLLs within different occupational categories: Group
1, consisting of individuals with direct occupational exposure to lead, exhibited higher BLLs compared to
both Group 2 and Group 3. This observation aligns with the facts, as these professions involve direct contact
with lead-containing materials and processes, resulting in an increased risk of lead exposure. Group 2
individuals vulnerable to indirect air pollution demonstrated higher BLLs compared to Group 3. This finding
highlights the impact of environmental exposure, particularly through air pollution generated by vehicular
activities. The elevated BLLs in Group 2 emphasize the importance of considering not only direct
occupational exposure but also indirect environmental factors when assessing lead exposure risks. Group 3,
consisting of individuals not directly involved in lead-associated occupations, exhibited comparatively lower
BLLs but higher than permissible levels. This suggests that their occupations involve minimal direct
exposure to lead-containing materials or processes. However, it's crucial to note that even within this group,
individuals may still encounter environmental lead exposure, albeit to a lesser extent than the occupational
groups in Groups 1 and 2.
The observed reduction in the proportion of individuals with BLLs ≥5 mcg/dL at baseline and end of follow-
up surveys among the overall participant cohort is significant. Moreover, the study's findings demonstrate a
significant reduction in the proportion of individuals with BLLs ≥5 mcg/dL over the study period,
particularly within high-risk occupational groups. This underscores the importance of preventive activities
and emphasizes the importance of targeted strategies to further reduce lead exposure.
However, the lack of statistically significant changes observed in various health parameters, including
abnormal serum creatinine levels, anemia prevalence, and neurological assessments, between baseline and
end of follow-up surveys indicates that even prevention activities during the study period did not have a
2024 Gupta et al. Cureus 16(2): e54432. DOI 10.7759/cureus.54432 9 of 11
discernible impact on these health outcomes.
Irreversible damage to kidney and neurological functions can occur as a consequence of exposure to elevated
BLLs. Similarly, another study documented possible kidney dysfunction at BLLs of 5-9 mcg/dL and possible
neurological dysfunction at BLLs ≥5 mcg/dL [12]. According to a prospective Swedish population-based
cohort study in 2018, among 4,341 individuals aged 46 to 67 years, after controlling for known risk factors,
individuals with high median lead concentrations had higher eGFR changes from baseline to follow-up
compared with those in the lowest quartiles [13]. In 2010, a study from the USA with 769 adolescent
participants aged 12 to 20 years found that as high as 10 mcg/dL BLLs were associated with a lower
estimated glomerular filtration rate (eGFR) [14]. Recent large-scale, prospective studies suggest that BLLs
below 10 mcg/dL significantly worsen neurological function [15].
What is particularly concerning is that even if BLLs are reduced to normal or lower levels, the adverse effects
on kidney and neurological functions may persist, showcasing a lack of reversibility in the damage incurred.
BLLs, even at concentrations below OSHA's cutoff guidelines [2], have the potential to cause irreversible
damage, particularly to the kidneys and nervous system.
In the current study, it was observed that the mean BLLs exceeded the recommended limits across all three
examined groups. It is plausible that occupational exposure is a contributing factor to the higher BLLs
observed in this population. Lead poses a significant risk to the central nervous system, and its
accumulation in the kidneys can result in kidney damage. There was no statistically significant change in
the proportion of participants with abnormal serum creatinine, abnormal VPT, abnormal reflexes, abnormal
muscle power, and anemia at baseline and end of follow-up surveys, despite a statistically significant
decrease in the proportion of participants with BLLs ≥5 mcg/dL. While decreasing lead exposure is an
essential step in preventing kidney and neural damage, it may not guarantee immediate or complete
improvement in kidney and neurological function, and additional measures may be necessary for addressing
kidney and neurological damage.
Nevertheless, the primary limitation of the study is that while the participants had abnormal serum
creatinine, abnormal VPT, abnormal reflexes, abnormal muscle power, and anemia, establishing a direct
causal relationship solely based on BLLs is challenging. Comprehensive clinical and biological
investigations are necessary to rule out alternative causes for these findings. In addition, a limited follow-up
time of six months and the self-selection of participants can further affect the outcome.
Conclusions
The study's findings demonstrate there was no change in serum creatinine, hemoglobin, or neurological
functions despite a significant reduction in the proportion of individuals with BLLs ≥5 mcg/dL over the
study period. This reinforces the critical importance of reevaluating the blood lead cutoff under the Factory
Act. Stringent preventive measures and ongoing health monitoring in populations at risk of lead exposure
are the utmost needs.
Additional Information
Author Contributions
All authors have reviewed the final version to be published and agreed to be accountable for all aspects of the
work.
Concept and design: Arti Gupta, Rakesh Upparakadiyala, Bari Siddiqui MA, Desai V. Sripad, Desu Rama
Mohan, Prudhvinath A. Reddy, Vamsikrishna Reddy K, Mukesh Tripathi
Acquisition, analysis, or interpretation of data: Arti Gupta, Rakesh Upparakadiyala, Bari Siddiqui MA,
Desai V. Sripad, Desu Rama Mohan, Prudhvinath A. Reddy, Vamsikrishna Reddy K, Mukesh Tripathi
Drafting of the manuscript: Arti Gupta
Critical review of the manuscript for important intellectual content: Arti Gupta, Rakesh
Upparakadiyala, Bari Siddiqui MA, Desai V. Sripad, Desu Rama Mohan, Prudhvinath A. Reddy, Vamsikrishna
Reddy K, Mukesh Tripathi
Supervision: Arti Gupta, Mukesh Tripathi
Disclosures
Human subjects: Consent was obtained or waived by all participants in this study. All India Institute of
Medical Sciences, Mangalagiri issued approval AIIMS/MG/IEC/2022-23/135. Animal subjects: All authors
have confirmed that this study did not involve animal subjects or tissue. Conf licts of interest: In
compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services
2024 Gupta et al. Cureus 16(2): e54432. DOI 10.7759/cureus.54432 10 of 11
info: The intramural grant was received from All India Institute of Medical Sciences Mangalagiri to conduct
the study. Financial relationships: All authors have declared that they have no financial relationships at
present or within the previous three years with any organizations that might have an interest in the
submitted work. Other relationships: All authors have declared that there are no other relationships or
activities that could appear to have influenced the submitted work.
Acknowledgements
We express our gratitude to the All India Institute of Medical Sciences, Mangalagiri, for funding this study.
Additionally, we extend our thanks to the traffic police in Guntur, the Auto Union in Mangalagiri, ANM,
ASHAs, staff nurses, and Anganwadi workers for their support in conducting the study.
References
1. CDC Updates Blood Lead Reference Value to 3.5 µg/dL . (2024). Accessed: 1 Jan 2024:
https://www.cdc.gov/nceh/lead/news/cdc-updates-blood-lead-reference-value.html .
2. Lead. (2024). Accessed: 1 Jan 2024: https://www.osha.gov/lead .
3. Kalahasthi R, Barman T: Assessment of lead exposure and urinary-δ-aminolevulinic acid levels in male lead
acid battery workers in Tamil Nadu, India. J Health Pollut. 2018, 8:6-13. 10.5696/2156-9614-8.17.6
4. Sanders T, Liu Y, Buchner V, Tchounwou PB: Neurotoxic effects and biomarkers of lead exposure: a review .
Rev Environ Health. 2009, 24:15-45. 10.1515/reveh.2009.24.1.15
5. Téllez-Rojo MM, Bellinger DC, Arroyo-Quiroz C, et al.: Longitudinal associations between blood lead
concentrations lower than 10 microg/dL and neurobehavioral development in environmentally exposed
children in Mexico City. Pediatrics. 2006, 118:323-30. 10.1542/peds.2005-3123
6. Chambial S, Shukla KK, Dwivedi S, Bhardwaj P, Sharma P: Blood lead level (BLL) in the adult population of
Jodhpur: a pilot study. Indian J Clin Biochem. 2015, 30:357-9. 10.1007/s12291-015-0496-y
7. Wani AL, Ara A, Usmani JA: Lead toxicity: a review. Interdiscip Toxicol. 2015, 8:55-64. 10.1515/intox-2015-
0009
8. Singamsetty B, Gollapalli PK: A study on health profile of workers in a battery factory with reference to lead
toxicity: six months study. Int J Community Med Public Health. 2017, 4:1519-25. 10.18203/2394-
6040.ijcmph20171594
9. Post-Hoc Power Calculator . (2023). Accessed: 1 Jan 2024: https://clincalc.com/stats/Power.aspx.
10. Pacer EJ, Palmer C D, Parson PJ: Determination of lead in blood by graphite furnace atomic absorption
spectrometry with Zeeman background correction: improving a well-established method to support a lower
blood lead reference value for children. Spectrochim Acta B: At Spectrosc. 2022, 190:106324.
10.1016/j.sab.2021.106324
11. Bush VJ, Smola C, Schmitt P: Evaluation of the Beckman Coulter DxC 700 AU chemistry analyzer . Pract Lab
Med. 2020, 18:00148. 10.1016/j.plabm.2019.e00148
12. Kosnett MJ, Wedeen RP, Rothenberg SJ, et al.: Recommendations for medical management of adult lead
exposure. Environ Health Perspect. 2007, 115:463-71. 10.1289/ehp.9784
13. Harari F, Sallsten G, Christensson A, et al.: Blood lead levels and decreased kidney function in a population-
based cohort. Am J Kidney Dis. 2018, 72:381-9. 10.1053/j.ajkd.2018.02.358
14. Fadrowski JJ, Navas-Acien A, Tellez-Plaza M, Guallar E, Weaver VM, Furth SL: Blood lead level and kidney
function in US adolescents: the Third National Health and Nutrition Examination Survey. Arch Intern Med.
2010, 170:75-82. 10.1001/archinternmed.2009.417
15. Mason LH, Harp JP, Han DY: Pb neurotoxicity: neuropsychological effects of lead toxicity . Biomed Res Int.
2014, 2014:840547. 10.1155/2014/840547
2024 Gupta et al. Cureus 16(2): e54432. DOI 10.7759/cureus.54432 11 of 11
