The human body features specialized anatomical zones where physiological, reproductive, and excretory systems converge, demanding rigorous scientific study and precise clinical terminology. The anogenital region represents one of the most clinically sensitive, morphologically complex, and diagnostically critical areas within human medicine, public health, and evolutionary biology. Comprehending its structural boundaries, neurovascular architecture, developmental origins, and associated pathologies is vital for fields ranging from pediatric endocrinology and forensic examination to oncology and dermatology.
Anogenital
1. Concise Definition
The term anogenital is a compound anatomical and clinical adjective describing the contiguous physical region that encompasses both the external genitalia and the anus, including the intervening perineal tissue. In medical nomenclature, it denotes structures, lesions, physiological processes, or pathological conditions situated within, or simultaneously affecting, the anus and the reproductive organs.
Beyond its purely topographical definition, the anogenital complex represents a distinct embryological unit originating from the primitive cloaca and genital tubercle. In developmental biology and endocrinology, the metric known as anogenital distance (AGD) serves as an established, sensitive biomarker of prenatal androgen exposure and endocrine disruption. Clinically, the region is recognized as a unified mucosal and cutaneous ecosystem susceptible to specific sexually transmitted infections, dermatoses, and hormone-mediated oncological transformations.
Consequently, the term functions not merely as a geographic descriptor of the human perineum, but as an operational construct across multiple biomedical disciplines. Whether delineating the mapping of oncogenic human papillomavirus infections, assessing congenital anomalies in neonates, or documenting soft-tissue findings in forensic medicine, the anogenital designation unifies interconnected visceral, epithelial, and neuromuscular systems.
2. Etymology & Linguistic Origin
The word anogenital is an anatomical neologism formed through the synthesis of classical Latin roots, reflecting the standardized conventions of biomedical nomenclature established during the nineteenth century. The initial combining element, ano-, is derived directly from the classical Latin noun ānus, denoting a “ring,” “circular band,” or “the terminal orifice of the alimentary canal.” In classical usage, the term metaphorically captured the ring-like, muscular conformation of the anal sphincter apparatus.
The secondary component, -genital, originates from the Latin adjective genitālis, meaning “pertaining to generation, birth, or reproduction.” This adjective is rooted in the third-conjugation verb gignere (supine stem genitum), which translates as “to beget, bear, or produce,” sharing deep Indo-European cognates with the root *genə- (to produce, give birth). The combining form entered modern medical lexicons in nineteenth-century anatomical descriptions to demarcate contiguous, shared fields of observation that crossed traditional borders between gastrointestinal and urogenital classifications.
Throughout the early twentieth century, the term migrated from descriptive gross anatomy into specialized subfields. Developmental embryologists adopted it to describe the rupture of the cloacal membrane and the partitioning of the cloacal fossa. Concurrently, venereologists and dermatologists established compound entities such as “anogenital pruritus,” “anogenital dermatoses,” and “anogenital warts” to categorize manifestations that traversed the cutaneous-mucosal boundary of the pelvic outlet.
3. Pronunciation & Grammatical Form
In standard English phonetics, the term is pronounced using the International Phonetic Alphabet (IPA) as /ˌeɪnoʊˈdʒɛnɪtəl/ in General American English and /ˌeɪnəʊˈdʒɛnɪtl/ in Received Pronunciation. Stress falls predominantly on the third syllable (-gen-), with a secondary stress occurring on the initial syllable (an-).
Grammatically, anogenital operates primarily as an adjective modifying a wide variety of anatomical, physiological, pathological, and forensic nouns. Common collocations in peer-reviewed literature include:
- Anogenital distance (AGD): The measured length between the center of the anus and the base of the genitalia.
- Anogenital warts (condylomata acuminata): Epithelial proliferations caused by low-risk strains of the human papillomavirus.
- Anogenital malignancy: Neoplasms arising within the vulvar, vaginal, penile, perianal, or anal epithelium.
- Anogenital trauma: Lacerations, contusions, or abrasions sustained in the pelvic outlet through injury, iatrogenic events, or assault.
Less frequently, the term is nominalized in colloquial clinical discourse as a collective noun phrase (“the anogenitals”), although such usage is non-standard and avoided in rigorous academic contexts. Its adverbial derivation, anogenitally, occurs rarely, predominantly in reconstructive surgery and anatomical positioning reports.
4. Detailed Conceptual Explanation
To fully grasp the scope of the anogenital concept, one must examine its structural architecture, functional boundaries, and histological properties. Topographically, the anogenital region forms the surface floor of the pelvis, spanning from the superior margin of the pubic symphysis anteriorly, continuing laterally along the ischiopubic rami and sacrotuberous ligaments, and terminating posteriorly at the coccyx. This rhomboid or diamond-shaped territory corresponds fundamentally to the perineum, which is conventionally subdivided by an imaginary transverse line connecting the ischial tuberosities into two operational triangles: the anterior urogenital triangle and the posterior anal triangle.
The hallmark of the anogenital field is that it represents an uninterrupted anatomical and epithelial continuum. Within this compact expanse, diverse epithelial types meet and transition. Keratinized stratified squamous epithelium of the external perineal skin transitions into modified, non-keratinized or partially keratinized mucosal surfaces of the vulva and distal anal canal (anoderm), which further merges with columnar epithelium at the dentate line. These transformation zones are characterized by heightened mitotic vulnerability, rendering them unique reservoirs for persistent viral colonization, immune-mediated inflammatory reactions, and neoplastic transformation.
Neurologically and vascularly, the anogenital field exhibits dense somatic, autonomic, and sensory convergence. Somatic innervation is largely coordinated via the pudendal nerve (originating from spinal roots S2–S4), which branches into the inferior rectal nerve, the perineal nerve, and the dorsal nerve of the clitoris or penis. This complex network endows the region with exceptional tactile, nociceptive, and erogenous sensitivity. Vascular perfusion is similarly integrated, governed predominantly by the internal pudendal artery and drained through extensive, communicating venous plexuses that link the systemic and portal venous circulations. This structural integration ensures that physiological adjustments—such as sexual arousal, urinary continence, and defecation—rely upon tightly synchronized muscular and vascular events across both the anal and genital triangles.
In human toxicology, teratology, and comparative morphology, the anogenital zone possesses an additional boundary: its quantitative physical dimension. The physical separation between the reproductive structures and the anal verge is not static; it is sculpted during early intrauterine life by endocrine signaling cascades. Consequently, the anogenital axis provides a non-invasive window into the systemic milieu of fetal development, demonstrating how molecular signals during the first trimester leave indelible structural signatures that persist into adulthood.
5. Historical Development
The formal demarcation of the anogenital field evolved alongside major paradigms in comparative anatomy, embryology, and sexual pathology. During the classical era of anatomical investigation in the Renaissance, pioneering morphologists such as Andreas Vesalius meticulously charted the pelvic floor muscles—such as the levator ani and external anal sphincter—yet treated the excretory and reproductive tracts as essentially distinct organ systems linked purely by spatial proximity.
A critical shift occurred during the late nineteenth and early twentieth centuries through advancements in developmental embryology. Researchers including Wilhelm His and later George L. Streeter elucidated the morphogenesis of the human cloaca. They observed that up to the sixth week of gestation, human embryos possess a common terminal cavity for the gut, urinary, and reproductive tracts. The discovery that the urorectal septum descends to partition this cloaca into an anterior urogenital sinus and a posterior anorectal canal established that the anus and external genitalia share an indivisible developmental history.
In the mid-twentieth century, experimental endocrinology accelerated the diagnostic importance of the anogenital region. Alfred Jost conducted landmark experiments on mammalian sexual differentiation, demonstrating that fetal testicular secretions dictate the masculinization of the indifferent external genitalia. During the 1960s and 1970s, veterinary teratologists identified that the distance between the anus and the phallic tubercle was sexually dimorphic across rodent models, serving as an exquisitely sensitive gauge of intrauterine androgen receptor activation.
The translation of these basic science findings to human medicine expanded dramatically in the early 2000s. Epidemiologists and pediatric researchers, notably Shanna Swan and colleagues, standardized anthropometric measurement protocols for human neonates, cementing anogenital distance as an indispensable epidemiological tool. Concurrently, the late twentieth-century identification of oncogenic human papillomaviruses by Harald zur Hausen reshaped anogenital oncology, proving that cervical, vulvar, penile, and anal squamous cell carcinomas share a singular, viral etiology concentrated within the squamocolumnar junctions of this integrated anatomical territory.
6. Theoretical Foundations
The academic study of the anogenital complex rests upon three primary theoretical frameworks: the morphogenetic partitioning model, the androgen-dependent programming window hypothesis, and the field cancerization theory.
The morphogenetic partitioning model provides the embryological foundation. It posits that proper anogenital formation depends on a complex interplay between endoderm-derived tissues and surrounding mesenchyme. As the urorectal septum fuses with the cloacal membrane, it establishes the central perineal tendon (the perineal body). Failure of this partitioning leads to a wide spectrum of congenital malformations, known broadly as persistent cloaca or anorectal malformations (ARM), illustrating that anomalies in the genital and anal spheres are rarely isolated events, but rather manifestations of shared mesodermal developmental errors.
The androgen-dependent programming window hypothesis, grounded in evolutionary and reproductive endocrinology, explains anogenital dimorphism. This framework states that during a critical temporal window of fetal gestation (typically gestational weeks 8 to 14 in humans), high concentrations of dihydrotestosterone (DHT), converted from testosterone via 5α-reductase, stimulate the expansion of the perineal tissue, shifting the phallus away from the anus. In female fetuses, the absence of high DHT levels maintains a significantly shorter perineal span. Any exogenous interference during this critical window—such as maternal exposure to anti-androgenic chemicals like phthalates—impairs this process, leading to demasculinized anogenital metrics.
Finally, the field cancerization theory, originally articulated by Slaughter in mucosal tissues, applies directly to the anogenital epithelium. This paradigm holds that the entire anogenital epithelial lining shares biological susceptibility to chronic oncogenic insults, particularly mucosal types of the human papillomavirus (HPV). Because the anogenital tract comprises analogous transition zones characterized by immature metaplastic cells, a viral exposure can produce diffuse, multicentric intraepithelial neoplasias spanning the cervix, vagina, vulva, perineal body, and anal canal simultaneously.
7. Key Components, Types & Dimensions
The anogenital region can be broken down into discrete structural components, clinical subtypes of pathology, and quantitative anthropometric dimensions:
- Topographical and Structural Components:
- Perineal Body: The central fibromuscular mass where the bulbospongiosus, superficial transverse perineal, and external anal sphincter muscles converge, serving as the physical bridge between genital and anal structures.
- Urogenital Triangle: The anterior partition containing the external genitalia, urethral meatus, associated erectile bodies (corpora cavernosa and corpus spongiosum/vestibular bulbs), and superficial perineal pouch.
- Anal Triangle: The posterior partition dominated by the anal aperture, anal canal, external and internal anal sphincters, and the paired, fat-filled ischioanal fossae.
- Anoderm and Mucocutaneous Junction: The specialized, non-hair-bearing skin of the distal anal canal, extending from the perianal skin to the dentate (pectinate) line.
- Anthropometric Dimensions (Anogenital Metrics):
- AGD-AP (Anus to Posterior Fourchette/Base of Scrotum): The short anogenital distance, measuring the perineal span from the center of the anus to the posterior junction of the labia majora or the posterior junction of the scrotal sac.
- AGD-AC (Anus to Clitoris/Cephalad Phallus): The long anogenital distance, measuring from the center of the anus to the anterior insertion of the clitoral hood or the dorsal base of the penis.
- Classifications of Anogenital Pathology:
- Infectious: Viral (condylomata acuminata, herpes simplex virus), bacterial (syphilitic chancres, lymphogranuloma venereum), and fungal manifestations.
- Inflammatory Dermatoses: Conditions specifically targeting anogenital skin, including lichen sclerosus, lichen planus, and hidradenitis suppurativa.
- Pre-malignant and Malignant Lesions: Anogenital Intraepithelial Neoplasia (AIN, VIN, PIN) progressing to invasive squamous cell carcinoma.
- Traumatic & Forensic Classifications: Lacerations, contusions, fissures, and hematomas cataloged using forensic injury criteria.
8. Examples & Illustrative Cases
The clinical presentation of anogenital conditions varies widely depending on the patient’s developmental stage, exposure history, and immune competence. The following case illustrations demonstrate how anogenital assessments function across clinical disciplines.
Case 1: Pediatric Endocrine Assessment of Endocrine Disruption
A male infant born at 39 weeks of gestation presents with unilateral cryptorchidism and isolated glandular hypospadias. As part of a specialized endocrine evaluation, the pediatric team conducts standardized caliper measurements of the perineum. The infant’s AGD-AP is found to be significantly below the fifth percentile for gestational age and birth weight, while the penoscrotal transposition is noted. This reduced anogenital distance signals inadequate androgen signaling during the first trimester programming window, prompting comprehensive metabolomic screening and diagnostic investigation for environmental anti-androgen exposure.
Case 2: Multicentric Anogenital Intraepithelial Neoplasia
A 48-year-old female with a history of cervical intraepithelial neoplasia (CIN 3) treated via excisional cone biopsy presents with persistent, localized pruritus across the perineal body and anal margin. Physical examination under colposcopy reveals well-demarcated, acetowhite plaques with mosaic vascular patterns extending from the posterior fourchette across the cutaneous perineum to the anal verge. High-resolution anoscopy and concurrent vulvar biopsies confirm Vulvar Intraepithelial Neoplasia (VIN 2) and high-grade Anal Intraepithelial Neoplasia (AIN 3). Both lesions test positive for high-risk HPV-16, illustrating the concept of field cancerization across the interconnected anogenital epithelium.
Case 3: Forensic Evaluation of Acute Anogenital Trauma
An adult patient presents to an emergency department for a forensic medical examination following an alleged sexual assault. Specialized forensic documentation utilizing high-definition photography with alternate light sources (ALS) reveals micro-lacerations and petechial contusions localized to the fossa navicularis of the posterior fourchette, accompanied by radial superficial fissures of the anal verge at the 6 o’clock position. The forensic practitioner systematically details the tissue involvement across both the urogenital and anal triangles, distinguishing blunt mechanical forces from pre-existing dermatological disorders such as lichen sclerosus.
9. Measurement & Assessment
Assessing the anogenital region requires rigorous standardization, whether evaluating quantitative anthropometrics or diagnosing qualitative pathological changes. In clinical research and epidemiological surveillance, the measurement of anogenital distance requires strict protocols to ensure inter-rater reliability. Clinicians utilize vernier calipers or specialized optical image analysis with the subject placed in a standardized dorsal lithotomy or frog-leg position. Because physical measurements vary with body size, modern research normalizes raw AGD values against infant weight, length, or body mass index, calculating an anogenital index (AGI = AGD / weight in kg) to enable accurate cohort comparisons.
In diagnostic medicine, visual assessment relies on colposcopy, vulvoscopy, and high-resolution anoscopy (HRA). Application of 3% to 5% acetic acid induces temporary dehydration of dysplastic cells, causing anogenital intraepithelial neoplasias to appear as distinct “acetowhite” areas. Lugol’s iodine solution is frequently applied to detect glycogen-depleted malignant or dysplastic tissue. High-resolution anoscopy utilizes specialized instrumentation and high magnification to view the transformation zone of the anal canal, mirroring cervical screening techniques.
Histopathological evaluation remains the gold standard for verifying anogenital disease. Biopsies of persistent erosions, verrucous changes, or indurated plaques are analyzed using targeted immunohistochemistry, most notably p16INK4a and Ki-67 biomarkers, which indicate transcriptionally active high-risk HPV infection. Furthermore, microbiological assays, including transcription-mediated amplification and polymerase chain reaction (PCR) tests, identify pathogenic strains of Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum, and herpes simplex virus from anogenital swabs.
10. Applications & Practical Significance
The anogenital construct holds wide-ranging practical significance across several medical and scientific specialties:
Pediatric and Reproductive Endocrinology: AGD measurements provide a non-invasive, objective bioassay for reproductive health tracking. A shortened AGD in males is clinically correlated with impaired Leydig cell function, cryptorchidism, hypospadias, reduced testicular volume, and impaired semen parameters in adulthood. In females, an elongated AGD serves as a phenotypic marker for hyperandrogenic conditions, such as polycystic ovary syndrome (PCOS) and congenital adrenal hyperplasia (CAH).
Oncology and Preventive Medicine: Recognizing the anogenital field as a unified site of HPV-mediated carcinogenesis has transformed preventative health strategies. The deployment of universal, gender-neutral vaccination targeting high-risk HPV types (e.g., types 16 and 18) directly decreases the incidence of cervical, anal, vulvar, and penile cancers. Furthermore, high-risk groups—such as men who have sex with men (MSM) and individuals living with HIV—benefit from routine anogenital cancer screening protocols modeled on successful cervical Papanicolaou regimens.
Forensic Medicine and Clinical Toxicology: In clinical toxicology and public health, anogenital metrics allow researchers to evaluate the safety of ubiquitous industrial chemicals, such as plasticizers (phthalate esters) and pesticides, on human endocrine development. In clinical forensics, standardized forensic examination protocols of the anogenital structures yield vital medicolegal documentation required in legal adjudications of sexual violence, distinguishing acute trauma from accidental injuries, infectious presentations, or physiologic variants.
11. Research & Empirical Evidence
Over the past three decades, a vast body of empirical literature has consolidated the clinical value of anogenital investigations. Early foundational work by Foster and McIntyre in the late 1990s demonstrated that in utero exposure to anti-androgenic environmental agents systematically decreased AGD in male rodents while inducing reproductive tract malformations, establishing the “phthalate syndrome.”
In 2005, a groundbreaking human study led by Shanna Swan and colleagues provided the first direct epidemiological evidence that environmental phthalate exposure alters human male anogenital morphology. The study demonstrated that mothers with higher urinary concentrations of phthalate metabolites gave birth to male infants with significantly shortened anogenital distances. These findings have since been replicated globally across diverse cohorts in Europe, Asia, and North America. Subsequent long-term prospective research by Eisenberg et al. (2011) linked shorter adult AGD to significantly lower sperm concentration, total motile sperm count, and reduced serum testosterone, confirming that neonatal anogenital metrics serve as persistent predictors of adult male fecundity.
In oncology, landmark studies including the Anal Cancer HSIL Outcomes Research (ANCHOR) study, published by Palefsky et al. in the New England Journal of Medicine (2022), established that treating high-grade anal intraepithelial neoplasia (a precursor lesion localized to the anogenital canal) directly reduces the incidence of invasive anal cancer in high-risk populations. This trial validated the clinical utility of comprehensive anogenital surveillance protocols, paralleling decades of cervical cytology evidence.
12. Cultural & Cross-Cultural Considerations
The examination, discussion, and medical treatment of the anogenital region are deeply shaped by cultural beliefs, social taboos, and systemic stigmas. Across many global societies, the anatomical convergence of excretory and sexual functions renders the anogenital space a focus of modesty, shame, and ritual purity practices. Consequently, patients frequently delay seeking clinical care for debilitating conditions—such as anogenital pruritus, condylomata, or persistent rectovaginal bleeding—due to profound social embarrassment.
These cultural hesitations introduce serious public health challenges, particularly regarding HPV vaccination and screening. In certain conservative communities, vaccinating adolescents against anogenital sexually transmitted infections is met with resistance under the mistaken belief that it encourages sexual activity. Moreover, the practice of traditional female genital cutting (FGC) in parts of Northeast and West Africa results in severe, permanent architectural distortions across the anogenital region, leading to chronic perineal scarring, recurrent fistulae, and severe dyspareunia that require specialized reconstructive and cultural competency training for healthcare providers.
Language and health literacy also heavily influence diagnostic timelines. In many languages, vernacular vocabularies lack precise, non-pejorative anatomical terms to distinguish between the vulva, the vagina, the perineum, and the anus. Patients may use vague phrases like “private parts” or “stomach area,” complicating triage and leading to delayed diagnoses of anogenital malignancies until lesions reach advanced stages.
13. Criticisms, Debates & Limitations
Despite its clinical and scientific widespread utility, several debates and methodological limitations surround the anogenital construct.
A primary point of contention in environmental epidemiology concerns the precision and reproducibility of anogenital distance measurements in human infants. Unlike laboratory rodents, human neonates exhibit substantial variability in pelvic adiposity, thigh girth, and baseline somatic size. Variations in leg positioning, measuring tools, or infant crying during examination can skew readings. While the calculation of the Anogenital Index (AGI) partially normalizes for infant body size, critics argue that universal normative reference charts across different ethnic groups remain incomplete.
Another major clinical debate revolves around anal cancer screening recommendations. While cervical cancer screening is standard globally, routine anal cytology and high-resolution anoscopy for the broader population remain controversial. The equipment and specialized expertise required for HRA are concentrated primarily in urban tertiary referral centers, limiting access. Furthermore, overtreatment of low-grade intraepithelial lesions within the delicate anodermal tissue can cause iatrogenic complications, including chronic pain, fecal urgency, or anal stenosis, leading some clinicians to question whether universal screening is warranted outside high-risk cohorts.
In forensic contexts, over-interpretation of anogenital findings has historically generated severe legal controversies. Decades of forensic pathology research have demonstrated that the absence of visible anogenital trauma does not disprove non-consensual sexual contact, as the elastic properties of anogenital mucosal tissues often sustain no visible microscopic or macroscopic injury. Conversely, benign dermatological conditions, such as early-stage pediatric lichen sclerosus, have occasionally been misdiagnosed as signs of mechanical trauma, emphasizing the necessity of specialized dermatological and forensic expertise.
14. Related Terms & Distinctions
Clear distinctions between closely related anatomical and medical concepts are essential to avoid diagnostic confusion:
- Perineum vs. Anogenital: The perineum is a strictly defined anatomical floor and region extending between the thighs from the pubis to the coccyx. Anogenital functions broader as both a topographical and a clinical descriptor that encompasses the visceral orifices (urethra, vagina, anus), the intervening perineum, and related pathological processes affecting these combined systems.
- Urogenital vs. Anogenital: The term urogenital (or genitourinary) refers exclusively to the functional and organ systems of reproduction and urine excretion. In contrast, anogenital intentionally links the genital structures with the terminal gastrointestinal tract (the anus).
- Pelvic vs. Anogenital: The pelvis refers to the bony ring and the deep internal pelvic cavity containing the bladder, internal reproductive organs, and rectum. The anogenital region designates the external, superficial, and terminal boundaries of these tracts located on the pelvic floor.
- Perianal vs. Anogenital: Perianal refers strictly to the immediate skin circumference (within several centimeters) surrounding the anal orifice. Anogenital encompasses this perianal ring along with the entirety of the external genitalia and perineal body.
15. Summary / Key Takeaways
The anogenital region is a vital anatomical, developmental, and clinical crossroads of the human body. Arising from shared cloacal origins, it unifies the excretory and reproductive tracts into a contiguous field characterized by unique epithelial transition zones, rich neurovascular networks, and shared disease susceptibilities. In modern science, anogenital distance serves as a sensitive, non-invasive biomarker of prenatal androgen exposure and endocrine disruption. Clinically, the field is central to understanding multicentric viral carcinogenesis driven by HPV, the management of inflammatory dermatoses, and the execution of objective forensic evaluations. Mastering the anatomical, developmental, and pathological complexities of this region is essential for advancing reproductive health, improving early cancer detection, and providing comprehensive clinical care.
References
- Eisenberg, M. L., Hsieh, M. H., Pastuszak, A. W., Chalak, L. F., & Lipshultz, L. I. (2011). The relationship between anogenital distance and adult male fertility. Human Reproduction, 26(9), 2335–2340. https://doi.org/10.1093/humrep/der184
- Jost, A. (1953). Problems of fetal endocrinology: the gonadal and hypophyseal hormones. Recent Progress in Hormone Research, 8, 379–418. https://doi.org/10.1016/B978-1-4831-9826-2.50015-8
- Palefsky, J. M., Lee, J. Y., Jay, N., Goldstone, S. E., Darragh, T. M., Dunlevy, H. A., … & Stier, E. A. (2022). Treatment of anal high-grade squamous intraepithelial lesions to prevent anal cancer. New England Journal of Medicine, 386(24), 2273–2282. https://doi.org/10.1056/NEJMoa2201048
- Slaughter, D. P., Southwick, H. W., & Smejkal, W. (1953). “Field cancerization” in oral stratified squamous epithelium: clinical implications of multicentric origin. Cancer, 6(5), 963–968. https://doi.org/10.1002/1097-0142(195309)6:5<963::AID-CNCR2820060515>3.0.CO;2-Q
- Swan, S. H., Main, K. M., Liu, F., Stewart, S. L., Kruse, R. L., Calafat, A. M., … & Study for Future Families Research Team. (2005). Decrease in anogenital distance among male infants with prenatal phthalate exposure. Environmental Health Perspectives, 113(8), 1056–1061. https://doi.org/10.1289/ehp.8100