Abstract
Objectives. To determine characteristics and sources of exposure in veterans with elevated blood lead levels (BLLs).
Methods. We included users of US Veterans Health Administration care aged 18 years or older tested for BLL from October 2015 to September 2021. Prevalence of BLL 10 micrograms per deciliter (µg/dL) or higher and 25 µg/dL or higher was determined within demographic groups. Logistic regression analysis measured association of International Classification of Diseases, Tenth Revision, Clinical Modification‒coded conditions with elevated BLL. Electronic notes were reviewed for exposure sources.
Results. Among 1007 unique veterans with BLL 10 µg/dL or higher, prevalence of BLL 10 µg/dL or higher and 25 µg/dL or higher peaked at 4.9 and 1.3 per 100 000 veterans, respectively (fiscal year 2019), and was highest in non-Hispanic White men and those aged 25 to 34 years. Conditions predicted by elevated BLL were attention-deficit/hyperactivity disorder (ADHD) and nausea or vomiting. Firearms represented 70.1% of occupational and 85.9% of nonoccupational exposures. Toxicology consults occurred in 17 of 298 (6%) with BLL 25 µg/dL or higher.
Conclusions. Firearms were the largest exposure source among veterans with elevated BLL. Clinicians should be alert for potential conditions (including ADHD and nausea or vomiting in our study) associated with lead exposure. Standardization of care regarding toxicology referral practices is warranted. (Am J Public Health. 2022;112(S7):S670–S678. https://doi.org/10.2105/AJPH.2022.306936)
Lead is an inorganic chemical element that is highly toxic to humans when inhaled in the form of dust or fumes or ingested via contaminated food or water. Exposure to lead in the environment among US citizens has declined because of restrictions imposed on the use of lead in gasoline and paint from the 1970s through 1990s.1 As a consequence, the mean blood lead level (BLL) of the US population decreased from 12.8 micrograms per deciliter (µg/dL) in 1976–1980 to 0.82 µg/dL in 2015–2016.2
Lead serves no biological function, and many argue that there exists no safe level of lead in the blood; however, in 2009, the Council of State and Territorial Epidemiologists and Centers for Disease Control and Prevention defined elevated BLL as 10 µg/dL or greater in children and adults. In 2015, this threshold was reduced to 5 µg/dL or greater for children and adults.3 The most recent update of the reference value for elevated BLL to 3.5 µg/dL in 2021 currently applies to children only.4
Even at low levels, lead can adversely affect multiple organ systems of the human body, resulting in toxicity to the kidneys, liver, cardiovascular system, central nervous system, and reproductive system.5,6 Early symptoms of low-level toxicity may be nonspecific and vary from one individual to the next, contributing to misdiagnosis.7 Depending on duration of exposure, signs and symptoms of lead toxicity that have been documented among adults include hypertension, cardiovascular and ischemic heart disease, kidney dysfunction, neurocognitive deficits, headache, fatigue, abdominal pain, anorexia, constipation, arthralgia, myalgia, erectile dysfunction, decreased fertility, and spontaneous abortion.1,7–10
In adults, occupational exposure to lead is the most common cause of elevated BLL.11 The National Institute for Occupational Safety and Health’s Adult Blood Lead Epidemiology and Surveillance (ABLES) program monitors BLL among working adults aged 16 years or older in the United States.12 In its 2016 data summary from 26 participating states, ABLES reported that, among adults with known lead exposure, 90.3% with BLL 10 µg/dL or higher had an occupational exposure source.12 Most occupational exposures occurred in 1 of 4 main industry sectors: manufacturing, construction, services, or mining. The Occupational Safety and Health Administration considers a BLL of 25 µg/dL or higher as serious and warranting an inspection of the work site,13 and ABLES reports prevalence rates of BLL 25 µg/dL or higher as a subset of prevalence rates 10 µg/dL or higher in their data summaries of elevated BLL among employed adults. Nonoccupational exposure to lead may occur among adults during recreational activities involving firearms and ammunition; conducting home renovation projects; ingesting lead-containing imported medicines, foods, or spices; or engaging in hobbies involving exposure to lead-containing products.14–16 Retained bullet fragments from previous gunshot injuries may result in an ongoing source of elevated BLL.17
The Veterans Health Administration (VHA) is the largest integrated health care delivery system in the United States, with more than 1200 hospitals and clinics18 located across all 50 states, the District of Columbia, and US territories. Veterans who served in Iraq and Afghanistan and who have retained metal fragments caused by war-related injuries may be enrolled in a surveillance registry through the Toxic Embedded Fragment Surveillance Center, which includes monitoring for lead, among other potential toxins.19 However, specific lead medical management guidance and screening recommendations for veterans potentially exposed through other sources does not exist.
Our study aims were to (1) determine prevalence of elevated BLL of 10 µg/dL or greater and estimate association of medical conditions potentially linked to lead exposure among veterans and (2) determine sources of exposure and evaluate follow-up care among veterans with a BLL of 25 µg/dL or higher.
METHODS
Cases were defined as instances of a BLL of 10 µg/dL or higher among veterans aged 18 years or older who received care in VHA between October 1, 2015, and September 30, 2021. When individuals had multiple BLLs of 10 µg/dL or higher in a given fiscal year (October 1—September 30), the highest BLL for that individual during that fiscal year was counted. BLLs were identified via Logical Observation Identifiers Names and Codes 17052–2, 77307–7, and 5671–3 for measurement of lead from whole blood. Demographic data obtained for all individuals in the case cohort included age at time of blood lead testing, sex, race/ethnicity, and state of residence. We calculated prevalence per 100 000 users of VHA care based on denominator data for each demographic grouping obtained from the VHA Support Service Unique Patients Cube, an internal VHA data source used to analyze trends in unique patients treated.
We stratified results into 2 groups for prevalence rate calculations: those with a BLL of 10 µg/dL or higher and those with a BLL of 25 µg/dL or higher. For the subgroup of unique individuals with a BLL of 25 µg/dL or higher, we reviewed electronic medical record progress note documentation and health factor data to determine occupational and nonoccupational sources of exposure to lead. Follow-up care for this group was evaluated through extraction and analysis of (1) progress note titles to determine locations of follow-up specialty clinical consultation visits and (2) medication data for evidence of chelation treatment (e.g., succimer, dimercaprol, or edetate calcium disodium).
We extracted outpatient International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM; Hyattsville, MD: National Center for Health Statistics; 2015) codes for medical conditions considered to occur as potential harmful effects of lead exposure20,21 and grouped them into categories (Table A, available as a supplement to the online version of this article at https://www.ajph.org). We then performed logistic regression analysis to estimate association of condition categories (outcome variables) to increased BLL (predictor variable) expressed as a continuous variable in units of 1 µg/dL starting at 10 µg/dL. We presented results as adjusted odds ratios (AORs) with 95% confidence intervals (CIs). We used R version 4.1.1 (R Foundation for Statistical Computing, Vienna, Austria) to perform statistical analysis. We extracted all study data from the VHA Corporate Data Warehouse.22
RESULTS
From October 1, 2015, to September 30, 2021, 63 825 total tests for BLL were performed on 35 063 unique individuals aged 18 years or older. The rate of blood lead testing per 100 000 veterans in care decreased by fiscal year from a high of 122.8 tests per 100 000 in fiscal year 2016 to a low of 67.6 tests per 100 000 in fiscal year 2020. The total number of cases of elevated BLL of 10 µg/dL or higher during the study timeframe was 1566, occurring among 1007 unique individuals (2.9% of those tested for lead). During the study period, the prevalence rate of BLL 10 µg/dL or higher peaked in fiscal year 2019 at 4.9 per 100 000 individuals in VHA care (Table 1). During the same fiscal year, the prevalence rate of BLL of 25 µg/dL or higher was also at its highest, at 1.3 per 100 000. Overall prevalence rates of BLL of 10 µg/dL or higher declined in fiscal years 2020 and 2021—3.4 and 3.0 per 100 000, respectively, with prevalence of BLL of 25 µg/dL or higher falling to 0.9 and 0.8 per 100 000, respectively.
TABLE 1—
Number and Prevalence Rates of US Veterans Health Administration (VHA) Users Aged 18 Years or Older With Elevated Blood Lead Levels (BLLs) of 10 Micrograms per Deciliter (μg/dL) or Higher and 25 μg/dL or Higher by Fiscal Year (FY): October 2015‒September 2021
| Characteristic | FY2016 | FY2017 | FY2018 | FY2019 | FY2020 | FY2021 | ||||||
| BLL ≥ 10 µg/dL, No. (Rate) | BLL ≥ 25 µg/dL, No. (Rate) | BLL ≥ 10 µg/dL, No. (Rate) | BLL ≥ 25 µg/dL, No. (Rate) | BLL ≥ 10 µg/dL, No. (Rate) | BLL ≥ 25 µg/dL, No. (Rate) | BLL ≥ 10 µg/dL, No. (Rate) | BLL ≥ 25 µg/dL, No. (Rate) | BLL ≥ 10 µg/dL, No. (Rate) | BLL ≥ 25 µg/dL. No. (Rate) | BLL ≥ 10 µg/dL, No. (Rate) | BLL ≥ 25 µg/dL, No. (Rate) | |
| Total | 243 (3.9) | 72 (1.2) | 293 (4.7) | 72 (1.1) | 286 (4.5) | 68 (1.1) | 317 (4.9) | 82 (1.3) | 222 (3.4) | 61 (0.9) | 205 (3.0) | 55 (0.8) |
| Age group, y | ||||||||||||
| < 25 | 3 (3.1) | 3 (3.1) | 3 (3.3) | 1 (1.1) | 4 (4.2) | 0 (0.0) | 3 (3.2) | 2 (2.1) | 1 (1.2) | 1 (1.2) | 0 (0.0) | 0 (0.0) |
| 25–34 | 34 (6.2) | 12 (2.2) | 43 (8.0) | 14 (2.6) | 43 (8.3) | 14 (2.7) | 56 (10.9) | 20 (3.9) | 36 (7.3) | 8 (1.6) | 22 (4.2) | 9 (1.7) |
| 35–44 | 21 (4.1) | 6 (1.2) | 41 (7.6) | 7 (1.3) | 25 (4.3) | 7 (1.2) | 36 (5.7) | 10 (1.6) | 34 (5.1) | 10 (1.5) | 30 (3.9) | 8 (1.0) |
| 45–54 | 39 (5.1) | 11 (1.4) | 37 (4.9) | 7 (0.9) | 29 (3.9) | 4 (0.5) | 44 (5.8) | 8 (1.1) | 28 (3.7) | 13 (1.7) | 30 (3.7) | 7 (0.9) |
| 55–64 | 45 (3.9) | 14 (1.2) | 40 (3.5) | 15 (1.3) | 39 (3.5) | 12 (1.1) | 46 (4.1) | 14 (1.3) | 35 (3.2) | 12 (1.1) | 37 (3.2) | 6 (0.5) |
| 65–74 | 89 (4.7) | 23 (1.2) | 103 (5.4) | 24 (1.3) | 123 (6.4) | 26 (1.4) | 99 (5.2) | 21 (1.1) | 60 (3.2) | 13 (0.7) | 57 (3.1) | 18 (1.0) |
| 75–84 | 11 (1.4) | 3 (0.4) | 23 (2.8) | 4 (0.5) | 23 (2.7) | 5 (0.6) | 27 (3.0) | 7 (0.8) | 24 (2.5) | 4 (0.4) | 25 (2.3) | 5 (0.5) |
| ≥ 85 | 1 (0.2) | 0 (0.0) | 3 (0.6) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 6 (1.2) | 0 (0.0) | 4 (0.8) | 0 (0.0) | 4 (0.8) | 2 (0.4) |
| Sex | ||||||||||||
| Male | 239 (4.3) | 71 (1.3) | 286 (5.1) | 71 (1.3) | 281 (5.0) | 67 (1.2) | 314 (5.5) | 81 (1.4) | 219 (3.9) | 61 (1.1) | 196 (3.4) | 53 (0.9) |
| Female | 4 (0.6) | 1 (0.2) | 7 (1.1) | 1 (0.2) | 5 (0.7) | 1 (0.1) | 3 (0.4) | 1 (0.1) | 3 (0.4) | 0 (0.0) | 9 (0.9) | 2 (0.2) |
| Race/ethnicity | ||||||||||||
| Non-Hispanic Black | 23 (2.3) | 11 (1.1) | 22 (2.2) | 5 (0.5) | 11 (1.1) | 2 (0.2) | 25 (2.3) | 8 (0.7) | 9 (0.8) | 3 (0.3) | 18 (1.6) | 4 (0.4) |
| Non-Hispanic White | 195 (4.5) | 54 (1.2) | 241 (5.5) | 58 (1.3) | 242 (5.5) | 54 (1.2) | 248 (5.5) | 63 (1.4) | 190 (4.3) | 54 (1.2) | 162 (3.6) | 44 (1.0) |
| Hispanic or Latino | 9 (2.5) | 3 (0.8) | 14 (3.7) | 7 (1.9) | 11 (2.8) | 7 (1.8) | 23 (5.6) | 8 (1.9) | 13 (3.1) | 4 (0.9) | 6 (1.4) | 2 (0.5) |
| Othera | 6 (3.9) | 1 (0.6) | 9 (5.7) | 1 (0.6) | 8 (4.8) | 3 (1.8) | 11 (6.3) | 2 (1.1) | 3 (1.7) | 0 (0.0) | 7 (3.7) | 3 (1.6) |
| Unknown | 10 (1.4) | 3 (0.4) | 7 (1.0) | 1 (0.1) | 14 (2.1) | 2 (0.3) | 10 (1.5) | 1 (0.2) | 7 (1.0) | 0 (0.0) | 12 (1.9) | 2 (0.3) |
Note. The sample size was n = 1566. Rates are per 100 000 unique users of VHA care by fiscal year. Denominator data were obtained from the VHA Support Service Center Unique Patients Cube (VHA internal data source). For individuals with multiple BLLs ≥ 10 µg/dL in a given FY, the highest BLL for that individual for that year was counted. To view denominator data by FY, stratified by characteristic, see Table B (available as a supplement to the online version of this article at https://www.ajph.org). Numbers and rates of individuals with BLL ≥ 25 µg/dL are subsets of the numbers and rates of those ≥ 10 µg/dL.
“Other” category includes Asian, American Indian/Alaska Native, and Native Hawaiian/Pacific Islander.
Among demographic groups studied, prevalence of elevated BLL of 10 µg/dL or higher was highest among men (peak prevalence rate 5.5 per 100 000 in fiscal year 2019), aged 25 to 34 years (peak prevalence rate 10.9 per 100 000 in fiscal year 2019), non-Hispanic White race/ethnicity (peak prevalence rates 5.5 per 100 000 in fiscal years 2017–2019), and those living in Wyoming, New Hampshire, Wisconsin, Connecticut, and Rhode Island (Figure 1; prevalence rates 10.1, 12.5, 12.6, 21.2, and 30 per 100 000, respectively, in fiscal year 2019).
FIGURE 1—
Prevalence Rates of US Veterans Health Administration (VHA) Users Aged 18 Years or Older With an Elevated Blood Lead Level (BLL) of 10 Micrograms per Deciliter (μg/dL) or Higher by US State and Territory: Fiscal Year 2019
Note. Per 100 000 unique users of VHA care. Denominator data were obtained from the VHA Support Service Center Unique Patients Cube (VHA internal data source). States with the highest prevalence of elevated BLL of 10 μg/dL or higher in fiscal year 2019 were Wyoming, New Hampshire, Wisconsin, Rhode Island, and Connecticut (10.1, 12.5, 12.6, 21.2, and 30 per 100 000 users of VHA care, respectively).
Table 2 presents results of logistic regression analysis of 22 ICD-10-CM‒coded condition categories potentially associated with elevated BLL. We found that attention-deficit/hyperactivity disorder (ADHD) and nausea or vomiting were predicted by elevated BLL after adjusting for sex, race/ethnicity, and age (AOR = 1.02; 95% CI = 1.00, 1.04 and AOR = 1.02; 95% CI = 1.00, 1.04, respectively).
TABLE 2—
ICD-10-CM‒Coded Conditions Potentially Associated With Elevated Blood Lead Levels (BLLs) Among US Veterans Health Administration (VHA) Users Aged 18 Years or Older: October 2015‒September 2021
| Conditiona | Elevated BLL ≥ 10 µg/dL (n = 1007) No. (%) | AORb (95% CI) |
| Abdominal pain | 185 (18.4) | 1.00 (0.90, 1.01) |
| Anemia | 95 (9.4) | 1.00 (0.98, 1.02) |
| Anorexia | 53 (5.3) | 0.99 (0.96, 1.01) |
| Arthralgia/myalgia | 772 (76.7) | 1.00 (0.99, 1.02) |
| Attention-deficit/hyperactivity disorder | 49 (4.9) | 1.02 (1.00, 1.04) |
| Cardiovascular/ischemic heart disease | 154 (15.3) | 1.01 (0.99, 1.02) |
| Constipation | 57 (5.7) | 0.99 (0.96, 1.01) |
| Diarrhea | 97 (9.6) | 1.01 (0.99, 1.02) |
| Dizziness | 114 (11.3) | 1.01 (0.99, 1.02) |
| Erectile dysfunction | 220 (21.8) | 0.99 (0.98, 1.00) |
| Fatigue/weakness | 204 (20.3) | 1.00 (0.99, 1.01) |
| Gout | 69 (6.9) | 1.01 (0.99, 1.02) |
| Headache/migraine | 216 (21.4) | 1.01 (1.00, 1.02) |
| Hearing loss/tinnitus | 433 (43.0) | 1.00 (0.99, 1.01) |
| Hypertension | 531 (52.7) | 1.01 (1.00, 1.02) |
| Kidney dysfunction (mild/moderate) | 76 (7.5) | 0.98 (0.96, 1.00) |
| Mood disorder/depression | 373 (37.0) | 1.00 (0.99, 1.01) |
| Nausea/vomiting | 73 (7.2) | 1.02 (1.00, 1.04) |
| Neurocognitive deficit | 70 (7.0) | 1.00 (0.98, 1.02) |
| Neuropathy | 112 (11.1) | 1.00 (0.99, 1.02) |
| Reproductive problems | 63 (6.3) | 1.00 (0.99, 1.03) |
| Tremor | 36 (3.6) | 0.97 (0.93, 1.00) |
Note. AOR = adjusted odds ratio; CI = confidence interval; ICD-10-CM = International Classification of Diseases, Tenth Revision, Clinical Modification (Hyattsville, MD: National Center for Health Statistics; 2015); µg/dL = micrograms per deciliter.
Outpatient ICD-10-CM conditions potentially associated with elevated BLL were derived from National Institute for Occupational Safety and Health20 and California Department of Public Health.21 Conditions that were secondary to other medical conditions (e.g., diabetic neuropathy and arthralgia due to osteoarthritis) were excluded.
Odds ratios are per unit change in BLL and are adjusted for sex, race/ethnicity, and age.
Among 298 adults with an elevated BLL of 25 µg/dL or higher, we found 282 exposure sources for 271 individuals (91%) through electronic medical record review (Table 3). Eleven individuals had more than one type of exposure, and 27 individuals had no documented exposure source in their medical record and were therefore excluded from this analysis. Of 282 exposures, 204 (72.3%) were occupational and 78 (27.7%) were nonoccupational. Most occupational exposures were firearm-related (n = 143; 70.1%), including 108 exposures through employment at firing ranges or gun stores, 26 firearm instructors or gunsmiths, and 6 employed in firearm or bullet manufacturing. Three individuals acquired military combat‒related retained bullet fragments that served as ongoing sources of lead exposure.
TABLE 3—
US Veterans Health Administration (VHA) Users Aged 18 Years or Older With Elevated Blood Lead Level (BLL) of 25 μg/dL or Higher by Source of Exposure: October 2015‒September 2021
| Exposure Type | Occupational (n = 204) No. (%) | Nonoccupational (n = 78) No. (%) |
| Firearm-related (n = 210; 74.5%) | 143 (70.1) | 67 (85.9) |
| Firing range or gun store employment | 108 | |
| Recreational shooting | 56 | |
| Firearms instructor or gunsmith | 26 | |
| Firearm or bullet manufacturing | 6 | |
| Military combat‒related retained bullet fragments | 3 | |
| Non‒military-related retained bullet fragments from assault or suicide attempt | 11 | |
| Not firearm-related (n = 72; 25.5%) | 61 (29.9) | 11 (14.1) |
| Services (auto mechanic, electrician, heating/cooling, lead recycling, antiques industry, stained glass repair, etc.) | 18 | |
| Battery, lead sinker, or other manufacturing | 17 | |
| Construction, painting, home renovation | 15 | |
| Home renovation | 6 | |
| Mining industry | 2 | |
| Hobbies (making fishing sinkers or stained glass) | 4 | |
| Ingested imported turmeric from India | 1 | |
| Unable to categorize | 9 |
Note. The sample size was n = 271 individuals with 282 exposures. Exposure source for 27 individuals out of total 298 cohort was not found, so they were excluded from this analysis. Eleven individuals had both occupational and nonoccupational exposure sources.
Among nonoccupational exposures, firearms constituted an even higher proportion of lead exposure sources (n = 67; 85.9%), with recreational shooting accounting for 56 exposures and retained bullet fragments acquired through nonmilitary exposures, such as assaults or suicide attempts. Among 72 exposures not related to firearms, 61 (29.9%) were occupational—primarily service industry (e.g., automotive, recycling, electrical, heating and cooling; n = 18), manufacturing (n = 17), and construction (n = 15) exposures. Nonoccupational exposures included home-renovation projects, hobbies such as making fishing sinkers or stained-glass projects, and exposure to contaminated products such as imported turmeric. In 9 cases, medical record documentation stated, for example, “works with lead” or similar comments that we were unable to categorize further.
A comparison of smoking status among individuals with firearm and nonfirearm sources of lead exposure indicated that 80% of individuals with non‒firearm-related sources of lead exposure were current or former smokers, while only 64.6% and 66.7% of those whose exposures were firearm-related or of unknown source, respectively, were current or former smokers (Table C, available as a supplement to the online version of this article at https://ajph.org).
In this group of 298 individuals with a BLL of 25 µg/dL or higher, succimer chelation treatment was ordered for 5 (1.7%) patients with peak BLLs greater than 45 µg/dL. Two patients with peak BLL less than 45 µg/dL were treated with succimer; however, these patients’ providers did not give specific reasons for chelation treatment in these individuals with BLL below the accepted threshold for initiation of chelation therapy.8,23
Our review of specialty consult requests for patients with BLL of 25 µg/dL or higher revealed that 54 (18%) were referred to hematology service, while only 17 (6%) were referred for a toxicology or environmental medicine consultation. Most toxicology or environmental medicine consults (n = 15; 88%) occurred at one facility: The Veterans Affairs Connecticut Healthcare System, West Haven Campus. Specific specialty consult requests were not found for the remaining 227 (76%) individuals. A separate electronic medical review of 10 individuals with the highest BLL (ranging between 69 and 112 µg/dL) revealed that none had been referred for internal VHA toxicology or environmental medicine consultation. Two had been referred for outside (non-VHA) toxicology consultation, results of which were scanned into the medical record as a generic “community care consult” and therefore not retrieved by our progress note title query. Of the remaining 8, 4 were referred for hematology consultation, and 4 had no consult referrals.
DISCUSSION
Our study demonstrated that nearly three quarters of individuals with an elevated BLL of 25 µg/dL or higher reported firearm-related exposures. This finding is not surprising in light of survey results published by Cleveland et al., which revealed that nearly half of all veterans are gun owners.24 Having learned to use and become comfortable with firearms in their military service, veterans may be more likely to seek occupations and recreational activities that involve the use of guns.25 Until recently, firing ranges were not widely recognized as sources of lead exposure, and many lack proper environmental controls and medical surveillance programs for employees.26,27 With increases in gun sales being reported during the COVID-19 pandemic,28 it is likely that lead exposure, both from shooting firearms and from acquiring retained bullet fragments as a result of firearm injury, will increase among the population at large.
Our finding related to smoking status with respect to firearm and nonfirearm exposure sources is of interest. It is known that smoking contributes to elevated BLL;29 however, the extent of its contribution when other sources are present is not fully understood and calls for further investigation.
The overall prevalence rate of elevated BLL among veterans aged 18 years or older cared for in the VHA peaked in fiscal year 2019, dropping to its lowest prevalence rate in fiscal year 2021. While the overall trend in US elevated BLL prevalence rates has been declining over the past several decades, it is likely that the fiscal year 2020–2021 reduction in prevalence in the VHA was attributable to decreased testing in these years. Similar reductions in childhood blood lead testing have been noted during the COVID-19 pandemic.30
Our study revealed several demographic differences in the prevalence of elevated BLL among veterans. We observed higher prevalence rates across all fiscal years among men and among individuals of non-Hispanic White race/ethnicity. As demonstrated by Cleveland et al., gun ownership is more common among men and non-Hispanic Whites.24 Across most fiscal years, persons aged 25 to 34 years had the highest prevalence rates of elevated BLL. Few studies have addressed age, sex, and race/ethnicity among adults with elevated BLL; however, Victory et al. demonstrated that, in Missouri, most adults with elevated BLL were male and of White race, though prevalence of elevated BLL was higher among those aged 35 years or older.31
Among children with elevated BLL, more individuals of non-Hispanic Black race/ethnicity are affected, while males and females are affected similarly.32 Demographic differences among adults compared with children may reflect differences in the sources and mechanisms of exposure to lead among these 2 groups; for example, adult exposures are more reflective of occupational and recreational sources, while children’s exposures are related to lead sources in their home and school environments and are more closely linked to poverty.
Our geographic distribution of prevalence rates among veterans with elevated BLL of 10 µg/dL or higher resembled that of the ABLES 2016 data summary, with increased rates seen across states in the Northeast, Midwest, and Wyoming.12 However, a more complete geographic comparison with ABLES data is limited because of numerous states not submitting data to the program.
Our analysis of ICD-10-CM‒coded medical conditions potentially associated with elevated BLL reinforced that these health effects may be difficult to recognize. Of 22 conditions examined, only ADHD and nausea or vomiting were significantly associated with elevated BLL after adjustment for sex, race/ethnicity, and age. Moreover, the odds of these 2 conditions increased by approximately 2% for every 1 unit of increase of BLL. While the association of ADHD with elevated BLL has been described in children, this association has not been well-recognized among adults.1
Conditions such as tremor and hypertension, which have been documented as associated with low-level lead exposure,1 were not revealed to be associated with elevated BLL in our study. Possible explanations for this lack of association include that our veteran population may be more inclusive of individuals with high levels of these conditions in general33,34 and that we did not include a control group without elevated BLL in our analysis. In addition, BLL may be a less reliable indicator of chronic conditions such as hypertension than an indicator of cumulative exposure such as bone lead measurement using K-shell x-ray fluorescence.5 Ideally, clinician decisions to test for lead should include potential occupational and recreational exposure history as well as, or in some cases regardless of, presence of medical conditions associated with lead exposure. We observed self-reporting of exposure history with request for lead testing to be the case in many patients whose medical records were reviewed.
Our observation of the lack of either toxicologist or environmental medicine consultations among individuals with elevated BLL of 25 µg/dL or higher and high number of referrals to hematologists, who likely have less training and expertise in the management of lead poisoning, was troubling. For veterans receiving care at the Veterans Affairs Connecticut Healthcare System, we found evidence of an internal VHA referral system for patients with elevated BLL. At other VHA facilities in other states, no internal referral system is in place, and clinicians may find it simpler to utilize existing state environmental health resources to provide consultation in caring for patients with elevated BLL. Inconsistencies in available referral systems, combined with a lack of existing national guidance, may contribute to an uneven level of care provided to veterans cared for at different hospitals within the VHA system.
Limitations
This study was subject to several limitations. Our study data source, VHA Corporate Data Warehouse, does not contain clinical records for patients who received care in non-VHA facilities unless these services were ordered and paid for by VHA; therefore, lead testing and outpatient ICD-10-CM coding episodes falling into this category would not be included in our study. ICD-10-CM‒coded conditions may have been miscoded or uncoded and, therefore, may not accurately represent conditions associated with lead exposure. In addition, the use of ICD-10-CM codes, rather than more specific laboratory indicators for the presence of such conditions as anemia, gout, hypertension, and kidney dysfunction, may have reduced our ability to reliably capture these conditions.
Despite our use of Logical Observation Identifiers Names and Codes that were specific for noncapillary samples, we did find one site that used capillary samples for lead screening. Among 8 patients at that site with capillary BLL 10 µg/dL or higher, no follow-up venous blood samples were collected; therefore, false elevation of these results cannot be ruled out. Our progress note title query did not capture toxicology or environmental health consults that were generically titled “Community Care Consult” as this title represents a wide variety of nonspecific consult types. We did not use a control group of individuals without elevated BLL in our analysis of ICD-10-CM‒coded conditions potentially associated with elevated BLL; therefore, our ability to detect associations may have been limited. Fewer than 1% of veterans in VHA care received lead testing; therefore, it is unknown whether lead toxicity may be a more widespread problem. Finally, our findings from a population of US veterans may not be generalizable to the larger US population.
Public Health Implications
Our findings highlight the risk of elevated BLL associated with use of firearms. An important first step in reducing risk is improving provider awareness of the role firearms play as a potential source of lead exposure. Clinicians caring for patients who use firearms in their occupations or recreationally should be aware that, in addition to including questions regarding safe storage of firearms in their homes, inquiring about the use of proper personal protective equipment while shooting at firing ranges and handling ammunition is warranted. Providers should also be alert for signs and symptoms as well as conditions that may be associated with lead toxicity (including ADHD and nausea or vomiting in our study) and obtain a BLL when patients report any potential exposure.
In addition to proper screening and testing of adult patients for potential risk factors for lead exposure, appropriate follow-up and medical management of individuals with elevated BLL is critical. VHA has greatly expanded its use of virtual care (telemedicine) to expand access to specialty care and to provide care outside of in-person visits during the COVID-19 pandemic.35,36 A potential innovative use of this program could be to expand availability of virtual toxicology or environmental health consultation to veterans with elevated BLL, thus improving access across VHA. The implementation of policy guidance and provider education regarding screening and treatment of lead-exposed individuals, along with improved access to toxicology or environmental health consultation, are important steps toward enhancing the care and prevention of lead toxicity in adults within the VHA health system. However, wider acknowledgment of the need to increase exposure-reduction activities at firing ranges and other high-risk settings are needed to prevent lead exposure among veterans and the general population.
ACKNOWLEDGMENTS
This work was carried out using Department of Veterans Affairs intramural funding and was not funded by external sources.
This work was presented previously, in part, at the Council of State and Territorial Epidemiologists 2021 Annual Conference.
Note. The opinions expressed are those of the authors and do not necessarily reflect those of the US Department of Veterans Affairs or US government.
CONFLICTS OF INTEREST
The authors have no conflicts of interest to disclose.
HUMAN PARTICIPANT PROTECTION
This project was approved by the Stanford University institutional review board (protocol ID 47191, “Public Health Surveillance in the Department of Veterans Affairs”), and written informed consent was waived.
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