Immunosuppression regimen and latitude impact keratinocyte carcinoma risk in U.S. liver transplant recipients.

Immunosuppression after solid organ transplantation is associated with an increased risk of keratinocyte carcinoma (KC). Despite its established morbidity, KC risk in liver transplant (LT) recipients is understudied, including the contribution of immunosuppression regimen and latitude. A retrospective cohort of 9,966 adult first LT alone recipients alive with their native allograft at 1-year post-LT without prior KC between 2007 and 2016 were identified using linked data from the Organ Procurement and Transplantation Network and Medicare administrative claims. The primary exposures were immunosuppression regimen and latitude of residence. The primary outcome was incident, de novo KC occurring at least 1-year after LT. Adjusted Cox regression analysis stratified by transplant center was used in all analyses. The cohort was 63.4% male, 70.2% White and with median age 61 years (interquartile range, IQR, 54-66) at transplant. Calcineurin inhibitor (CNI) with anti-metabolite combination was independently associated with incident KC when measured as intention-to-treat (adjusted hazard ratio (aHR) 1.21 vs. CNI monotherapy, 95% CI 1.02-1.43, p = 0.026), in a time-updating as-treated analysis (aHR 1.61, 95% CI 1.34-1.93; p < 0.001) and when measured as cumulative exposure (aHR 1.13 per 6-month increase, 95% CI: 1.02-1.33; p = 0.027). More southern latitude of residence was also independently associated with incident KC with an aHR of 1.26 per 5°N decrease towards the Equator (95% CI: 1.08-1.47, p = 0.003). We demonstrate independent effects of CNI with antiM immunosuppression regimen and latitude of residence on the risk of post-LT KC, which will better inform screening practices and immunosuppression management.

Maternal history of angioma is associated with infantile hemangioma and port-wine stain in children: a population-based, cohort study of mother-child pairs from the United Kingdom.

The two most prevalent childhood vascular abnormalities are infantile hemangioma (IH) and port-wine stain (PWS). They become apparent shortly after birth but have distinct pathophysiology and clinical manifestations. The goal of this study was to determine if mother's history of angioma or PWS is associated with these vascular abnormalities. We evaluated an UK anonymized electronic medical records database with medical records that were linked between children and their mothers. Cox proportional hazards models were used to evaluate the association between maternal factors and the time of onset of either IH or PWS in children. Between 2004 and 2021, 639,085 children were linked to their mom's medical data with a total of 4,270,773 person-years of follow up. Children born to mothers with an angioma as compared to a mother without an angioma were more than 60% more likely to have an IH (HR: 1.64 [1.07, 2.52]). Children born to mothers with a PWS as compared to children born to mothers without a PWS were nearly 20 times more likely to have a PWS (18.95 [4.71,76.26]). Mothers with angiomas were not more likely to have children with PWS and mothers with PWS were not more likely to have children with IH. The effect estimates were minimally changed after adjustment. We demonstrated that children born to mothers with angiomas or PWS were at increased risk of IH or PWS, respectively.

Antihypertensive Medications and Risk of Melanoma and Keratinocyte Carcinomas: A Systematic Review and Meta-Analysis.

Some antihypertensive medications are photosensitizing. The implications for skin cancer risk remain unclear because results from prior studies are inconsistent and as new evidence is published. We performed a systematic review and meta-analysis to evaluate the association between antihypertensives and common skin cancers (cutaneous squamous cell carcinoma, basal cell carcinoma, and melanoma) and to evaluate dose-response relationships. Forty-four articles met inclusion criteria, and 42 could be meta analyzed. Increased risks were seen for basal cell carcinoma with calcium channel blockers (relative risk [RR] = 1.17, 95% confidence interval [CI] = 1.11-1.22), diuretics (RR = 1.06, 95% CI = 1.03-1.10), and thiazides (RR = 1.10, 95% CI = 1.04-1.16); for squamous cell carcinoma with calcium channel blockers (RR = 1.08, 95% CI = 1.01-1.14), diuretics (RR = 1.29, 95% CI = 1.17-1.43), and thiazides (RR = 1.36, 95% CI = 1.15-1.61); and for melanoma in angiotensin-converting enzyme inhibitors (RR = 1.09, 95% CI = 1.03-1.14), calcium channel blockers (RR = 1.08, 95% CI = 1.03-1.12), and thiazides (RR = 1.09, 95% CI = 1.02-1.17). The quality of evidence was low or very low. We observed evidence for dose-response for thiazides with basal cell carcinoma; angiotensin-converting enzyme inhibitors, diuretics, and thiazides with squamous cell carcinoma; and angiotensin-converting enzyme inhibitors, diuretics, and thiazides with melanoma. Our meta-analysis supports a potential causal association between some antihypertensives, particularly diuretics, and skin cancer risk.

Cell-Type Specific Connectivity of Whisker-Related Sensory and Motor Cortical Input to Dorsal Striatum.

The anterior dorsolateral striatum (DLS) is heavily innervated by convergent excitatory projections from the primary motor (M1) and sensory cortex (S1) and considered an important site of sensorimotor integration. M1 and S1 corticostriatal synapses have functional differences in their connection strength with striatal spiny projection neurons (SPNs) and fast-spiking interneurons (FSIs) in the DLS and, as a result, exert distinct influences on sensory-guided behaviors. In the present study, we tested whether M1 and S1 inputs exhibit differences in the subcellular anatomical distribution of striatal neurons. We injected adeno-associated viral vectors encoding spaghetti monster fluorescent proteins (sm.FPs) into M1 and S1 in male and female mice and used confocal microscopy to generate 3D reconstructions of corticostriatal inputs to single identified SPNs and FSIs obtained through ex vivo patch clamp electrophysiology. We found that M1 and S1 dually innervate SPNs and FSIs; however, there is a consistent bias towards the M1 input in SPNs that is not found in FSIs. In addition, M1 and S1 inputs were distributed similarly across the proximal, medial, and distal regions of SPN and FSI dendrites. Notably, closely localized M1 and S1 clusters of inputs were more prevalent in SPNs than FSIs, suggesting that cortical inputs are integrated through cell-type specific mechanisms. Our results suggest that the stronger functional connectivity from M1 to SPNs compared to S1, as previously observed, is due to a higher quantity of synaptic inputs. Our results have implications for how sensorimotor integration is performed in the striatum through cell-specific differences in corticostriatal connections.

Keratinocyte Carcinoma Incidence by Race and Ethnicity in Older Adults With Medicare Coverage.

This cohort study examines raw and age-adjusted differences in the incidence of keratinocyte carcinoma among Medicare beneficiaries by race and ethnicity.

Skin Cancers in Medicare Beneficiaries With Actinic Keratoses.

Importance: Actinic keratoses (AK) are common premalignant skin lesions with a small risk of progressing to cutaneous squamous cell carcinoma (SCC). There is some evidence that patients with AKs also have increased risks of other skin cancers beyond SCC. However, the absolute risks of skin cancer in patients with AKs are unknown. Objective: To calculate the absolute and relative risks of future skin cancer in Medicare beneficiaries with AKs. Design, Setting, and Participants: This retrospective cohort study was performed using a deidentified, random sample of 4 999 999 fee-for-service Medicare beneficiaries from 2009 through 2018. Patients with treated AKs were included, and patients with seborrheic keratoses (SKs) were included as a comparator group. All patients were required to have at least 1 year between data set entry and first AK or SK. Patients with a history of skin cancer were excluded. Data were analyzed from September 2022 to March 2023. Main Outcomes and Measures: Outcomes were first surgically treated skin cancer, including keratinocyte carcinoma (including SCC and basal cell carcinoma [BCC]) and melanoma. The absolute risks of skin cancer in patients with AKs were evaluated. Skin cancer risks in patients with AKs were compared with patients with SKs using adjusted competing risks regression. Results: A total of 555 945 patients with AKs (mean [SD] age, 74.0 [7.4] years; 55.4% female) and 481 024 patients with SKs (mean [SD] age, 73.3 [7.3] years; 72.4% female) were included. The absolute risk of skin cancer after a first AK was 6.3% (95% CI, 6.3%-6.4%) at 1 year, 18.4% (95% CI, 18.3%-18.5%) at 3 years, and 28.5% (95% CI, 28.4%-28.7%) at 5 years. Patients with AKs had increased risk of skin cancer compared with patients with SKs (any skin cancer: adjusted hazard ratio [aHR], 2.17; 95% CI, 2.15-2.19; keratinocyte carcinoma: aHR, 2.20; 95% CI, 2.18-2.22; SCC: aHR, 2.63; 95% CI, 2.59-2.66; BCC: aHR, 1.85; 95% CI, 1.82-1.87; and melanoma: aHR, 1.67; 95% CI, 1.60-1.73). Conclusions and Relevance: In this cohort study, older patients with AKs had substantial absolute risks, as well as elevated relative risks, of skin cancer. AKs may be clinical markers of UV exposure and increased skin cancer risk, including SCC, BCC, and melanoma. However, guidelines are lacking for follow-up skin cancer surveillance in patients with AKs. Efforts to develop evidence-based recommendations for skin cancer surveillance in patients with AKs are paramount.

Association between atopic dermatitis, autoimmune illnesses, Epstein-Barr virus, and cytomegalovirus.

Atopic dermatitis (AD) is a Th2-driven inflammatory skin disease that has been associated with other autoimmune illnesses (AI) and has a well-known predisposition to infection with herpes simplex virus infection. Yet, few studies have evaluated the association between atopic dermatitis, autoimmune illness, and other human herpes virus (HHV) infections such as cytomegalovirus (CMV) and Epstein-Barr virus (EBV). We aimed to evaluate the association between AD, specific AIs, CMV, and EBV in a random sample of the Optum Clinformatics Data Mart database, a US administrative claims database. AD was defined based on ICD diagnostic codes. Patients with AD were exact matched to those without AD on sex, age at enrollment, time observed in the dataset and census division. Our outcomes of interest were rheumatoid arthritis (RA), Crohn's disease (CD), ulcerative colitis (UC), multiple sclerosis (MS), CMV, and EBV infection as defined by specific ICD codes. Logistic regression models were used to examine the association between AD and our outcomes of interest [odds ratio (95% confidence intervals)]. Our full cohort included 40,141,017 patients. In total, 601,783 patients with AD were included. As expected, patients with AD had a higher prevalence of asthma and seasonal allergies versus controls. Individuals with AD have an increased risk of EBV, CMV, RA, CD, UC, and MS. While we cannot demonstrate a causal association, the observed associations between AD and AI may be in part mediated by these types of HHV (i.e., CMV and EBV), a finding that merits further study.

Anatomic Locations of Procedurally Treated Keratinocyte Carcinomas in the US Medicare Population.

Importance: Keratinocyte carcinomas are the most common cancers in the US. However, keratinocyte carcinomas are not included in US national cancer registries, and information on the anatomic locations of keratinocyte carcinomas is lacking. Objective: To investigate the anatomic location of keratinocyte carcinomas in the US using a large claims data set. Design, Setting, and Participants: We performed a cohort study using a deidentified, random sample of 4 999 999 fee-for-service Medicare beneficiaries aged 65 years or older (2009-2018). Main Outcomes and Measures: Proportion of procedurally treated keratinocyte carcinomas at each anatomic location, identified by linking diagnosis and treatment codes. Results: A total of 2 415 514 keratinocyte carcinomas were identified in 792 393 beneficiaries. The mean (SD) age was 76.6 (8.1) years, 410 364 (51.8%) were women, and 96.7% were White. Of the 2 415 514 keratinocyte carcinomas, 796 542 could be subtyped into basal cell carcinoma (33.0%), 927 984 into squamous cell carcinoma (38.4%), and 690 988 (28.6%) could not be subtyped. The most common location of squamous cell carcinomas was the head and/or neck (44.3%) followed by upper limbs (26.7%). The most common location of basal cell carcinomas was head and/or neck (63.8%), followed by trunk (14.9%). In women, keratinocyte carcinomas were most common on the head and/or neck (47.3%) followed by upper and lower limb (18.5% and 16.6%, respectively). In men, keratinocyte carcinomas were most common on the head and/or neck (58.7%) followed by upper limb and trunk (17.3% and 11.4%, respectively). Conclusions and Relevance: The results of this large Medicare cohort study highlight the anatomic locations of keratinocyte carcinomas over recent years and show the predominance of lesions occurring at head and/or neck anatomic location. This foundational information on keratinocyte carcinoma anatomic locations in the US is valuable for improved keratinocyte risk factor differentiation and skin cancer surveillance.

Cell-Type Specific Connectivity of Whisker-Related Sensory and Motor Cortical Input to Dorsal Striatum.

The anterior dorsolateral striatum (DLS) is heavily innervated by convergent excitatory projections from the primary motor (M1) and sensory cortex (S1) and is considered an important site of sensorimotor integration. M1 and S1 corticostriatal synapses have functional differences in the strength of their connections with striatal spiny projection neurons (SPNs) and fast-spiking interneurons (FSIs) in the DLS, and as a result exert an opposing influence on sensory-guided behaviors. In the present study, we tested whether M1 and S1 inputs exhibit differences in the subcellular anatomical distribution onto striatal neurons. We injected adeno-associated viral vectors encoding spaghetti monster fluorescent proteins (sm.FPs) into M1 and S1, and used confocal microscopy to generate 3D reconstructions of corticostriatal inputs to single identified SPNs and FSIs obtained through ex-vivo patch-clamp electrophysiology. We found that SPNs are less innervated by S1 compared to M1, but FSIs receive a similar number of inputs from both M1 and S1. In addition, M1 and S1 inputs were distributed similarly across the proximal, medial, and distal regions of SPNs and FSIs. Notably, clusters of inputs were prevalent in SPNs but not FSIs. Our results suggest that SPNs have stronger functional connectivity to M1 compared to S1 due to a higher density of synaptic inputs. The clustering of M1 and S1 inputs onto SPNs but not FSIs suggest that cortical inputs are integrated through cell-type specific mechanisms and more generally have implications for how sensorimotor integration is performed in the striatum. Significance Statement: The dorsolateral striatum (DLS) is a key brain area involved in sensorimotor integration due to its dense innervation by the primary motor (M1) and sensory cortex (S1). However, the quantity and anatomical distribution of these inputs to the striatal cell population has not been well characterized. In this study we demonstrate that corticostriatal projections from M1 and S1 differentially innervate spiny projection neurons (SPNs) and fast-spiking interneurons (FSIs) in the DLS. S1 inputs innervate SPNs less than M1 and are likely to form synaptic clusters in SPNs but not in FSIs. These findings suggest that sensorimotor integration is partly achieved by differences in the synaptic organization of corticostriatal inputs to local striatal microcircuits.

Methotrexate Cutaneous Ulceration: A Systematic Review of Cases.

BACKGROUND: Methotrexate cutaneous ulceration is a rare methotrexate complication, and has only been described in case reports and case series. OBJECTIVE: To document patient characteristics, morphologic features, and mortality risk factors for methotrexate cutaneous ulceration. METHODS: A systematic literature review of PubMed and Embase (last date 1 November 2021) was performed with data collected from case reports and case series. This study was limited to cases of cutaneous ulceration; presence of oral ulceration was collected from within these cases. RESULTS: 114 cases (men = 57.9%, mean age = 61 years) of methotrexate cutaneous ulceration met inclusion criteria. Psoriasis (69.3%), rheumatoid arthritis (18.4%), and mycosis fungoides (6.1%) were the most common indications for methotrexate use. Morphologies included erosions localized to psoriatic plaques (33.3%), epidermal necrosis/necrolysis (35.1%), localized ulceration (16.7%), and skin-fold erosions (5.3%). Methotrexate dose preceding toxicity varied greatly; median 20 mg/week, interquartile range 15-40 mg/week, range 5-150 mg/week. Most patients had risk factors for serum toxicity (baseline renal dysfunction = 37.8%, concurrent NSAID use = 28.1%, inadequate folic acid use = 89.1%). Thirty percent of cases involved mistakenly high methotrexate doses. Fourteen patients (12%) died. Absence of folic acid use (69% vs. 100%, p value < 0.001), pancytopenia (33% vs. 86%, p value < 0.001), and renal dysfunction at presentation (47% vs. 92%, p value < 0.001) were associated with increased mortality. LIMITATIONS: Selection bias present due to abstraction from case reports and case series. CONCLUSION: Methotrexate cutaneous ulceration is commonly preceded by dosage mistakes, absence of folic acid supplementation, and concurrent use of nephrotoxic medications. Renal impairment, pancytopenia, and absence of folic acid supplementation are key risk factors for mortality from this adverse medication reaction. Providers should regularly monitor methotrexate dosing adherence, drug-drug interactions, and perform routine laboratory evaluation. Index of suspicion for this toxicity should remain high given the varied clinical presentation and high mortality.

Broad activation of the Parkin pathway induces synaptic mitochondrial deficits in early tauopathy.

Mitochondrial defects are a hallmark of early pathophysiology in Alzheimer's disease, with pathologically phosphorylated tau reported to induce mitochondrial toxicity. Mitophagy constitutes a key pathway in mitochondrial quality control by which damaged mitochondria are targeted for autophagy. However, few details are known regarding the intersection of mitophagy and pathologies in tauopathy. Here, by applying biochemical and cell biological approaches including time-lapse confocal imaging in live tauopathy neurons, combined with gene rescue experiments via stereotactic injections of adeno-associated virus particles into tauopathy mouse brains, electrophysiological recordings and behavioural tests, we demonstrate for the first time that mitochondrial distribution deficits at presynaptic terminals are an early pathological feature in tauopathy brains. Furthermore, Parkin-mediated mitophagy is extensively activated in tauopathy neurons, which accelerates mitochondrial Rho GTPase 1 (Miro1) turnover and consequently halts Miro1-mediated mitochondrial anterograde movement towards synaptic terminals. As a result, mitochondrial supply at tauopathy synapses is disrupted, impairing synaptic function. Strikingly, increasing Miro1 levels restores the synaptic mitochondrial population by enhancing mitochondrial anterograde movement and thus reverses tauopathy-associated synaptic failure. In tauopathy mouse brains, overexpression of Miro1 markedly elevates synaptic distribution of mitochondria and protects against synaptic damage and neurodegeneration, thereby counteracting impairments in learning and memory as well as synaptic plasticity. Taken together, our study reveals that activation of the Parkin pathway triggers an unexpected effect-depletion of mitochondria from synaptic terminals, a characteristic feature of early tauopathy. We further provide new mechanistic insights into how parkin activation-enhanced Miro1 degradation and impaired mitochondrial anterograde transport drive tauopathy-linked synaptic pathogenesis and establish a foundation for future investigations into new therapeutic strategies to prevent synaptic deterioration in Alzheimer's disease and other tauopathies.

FosGFP expression does not capture a sensory learning-related engram in superficial layers of mouse barrel cortex.

Immediate-early gene (IEG) expression has been used to identify small neural ensembles linked to a particular experience, based on the principle that a selective subset of activated neurons will encode specific memories or behavioral responses. The majority of these studies have focused on "engrams" in higher-order brain areas where more abstract or convergent sensory information is represented, such as the hippocampus, prefrontal cortex, or amygdala. In primary sensory cortex, IEG expression can label neurons that are responsive to specific sensory stimuli, but experience-dependent shaping of neural ensembles marked by IEG expression has not been demonstrated. Here, we use a fosGFP transgenic mouse to longitudinally monitor in vivo expression of the activity-dependent gene c-fos in superficial layers (L2/3) of primary somatosensory cortex (S1) during a whisker-dependent learning task. We find that sensory association training does not detectably alter fosGFP expression in L2/3 neurons. Although training broadly enhances thalamocortical synaptic strength in pyramidal neurons, we find that synapses onto fosGFP+ neurons are not selectively increased by training; rather, synaptic strengthening is concentrated in fosGFP- neurons. Taken together, these data indicate that expression of the IEG reporter fosGFP does not facilitate identification of a learning-specific engram in L2/3 in barrel cortex during whisker-dependent sensory association learning.

Risks of Multiple Skin Cancers in Organ Transplant Recipients: A Cohort Study in 2 Administrative Data Sets.

IMPORTANCE: There are limited reports on the risks of multiple primary skin cancers in organ transplant recipients (OTRs). OBJECTIVE: To determine the risks over time and risk factors for OTRs developing (1) any skin cancer posttransplant, (2) a subsequent skin cancer after the first posttransplant skin cancer in the data sets used in the study, and (3) 10 or more skin cancers. DESIGN, SETTING, AND PARTICIPANTS: This retrospective cohort study used data from Optum deidentified electronic health record data set (7.7 million patients) and Truven Health MarketScan insurance claims data set (161 million patients) from 2007 to 2017. Skin cancers were identified using diagnosis plus treatment codes for basal cell carcinoma, squamous cell carcinoma, and melanoma; OTRs were identified using 4 or more diagnosis codes for organ transplant. Data analysis took place from January 1, 2007, to December 31, 2017. MAIN OUTCOMES AND MEASURES: Cumulative risks of (1) any skin cancer treatment posttransplant, (2) a subsequent skin cancer treatment after the first posttransplant skin cancer treatment in our data, and (3) 10 or more skin cancer treatments in OTRs. A Wei-Lin-Weissfeld marginal model was used to evaluate risk factors for any skin cancer. RESULTS: A total of 7390 OTRs in Optum and 133 651 in MarketScan were identified, 4.5% and 13.3% of which had had at least 1 skin cancer treatment, respectively. At 2 years after the initial posttransplant skin cancer in the data sets, OTRs had a 44.0% to 57.0% risk of a subsequent skin cancer treatment and a 3.7% to 6.6% risk of having 10 or more skin cancer treatments. Statistically significant risk factors for any skin cancer included age, history of skin cancer, and history of actinic keratosis in both data sets, and male sex and thoracic transplant in MarketScan. CONCLUSIONS AND RELEVANCE: In this retrospective cohort study, approximately half of the OTRs who developed at least 1 posttransplant skin cancer developed a subsequent skin cancer within 2 years, and approximately 1 in 20 developed 10 or more skin cancers. Identifying OTRs at highest risk for multiple primary skin cancers may help target strategies for prevention and early detection.

Patterns of Atopic Eczema Disease Activity From Birth Through Midlife in 2 British Birth Cohorts.

IMPORTANCE: Atopic eczema is characterized by a heterogenous waxing and waning course, with variable age of onset and persistence of symptoms. Distinct patterns of disease activity such as early-onset/resolving and persistent disease have been identified throughout childhood; little is known about patterns into adulthood. OBJECTIVE: This study aimed to identify subtypes of atopic eczema based on patterns of disease activity through mid-adulthood, to examine whether early life risk factors and participant characteristics are associated with these subtypes, and to determine whether subtypes are associated with other atopic diseases and general health in mid-adulthood. DESIGN, SETTING, AND PARTICIPANTS: This study evaluated members of 2 population-based birth cohorts, the 1958 National Childhood Development Study (NCDS) and the 1970 British Cohort Study (BCS70). Participant data were collected over the period between 1958 and 2016. Data were analyzed over the period between 2018 and 2020. MAIN OUTCOMES AND MEASURES: Subtypes of atopic eczema were identified based on self-reported atopic eczema period prevalence at multiple occasions. These subtypes were the outcome in models of early life characteristics and an exposure variable in models of midlife health. RESULTS: Latent class analysis identified 4 subtypes of atopic eczema with distinct patterns of disease activity among 15 939 individuals from the NCDS (51.4% male, 75.4% White) and 14 966 individuals from the BCS70 (51.6% male, 78.8% White): rare/no (88% to 91%), decreasing (4%), increasing (2% to 6%), and persistently high (2% to 3%) probability of reporting prevalent atopic eczema with age. Sex at birth and early life factors, including social class, region of residence, tobacco smoke exposure, and breastfeeding, predicted differences between the 3 atopic eczema subtypes and the infrequent/no atopic eczema group, but only female sex differentiated the high and decreasing probability subtypes (odds ratio [OR], 1.99; 95% CI, 1.66-2.38). Individuals in the high subtype were most likely to experience asthma and rhinitis, and those in the increasing subtype were at higher risk of poor self-reported general (OR, 1.29; 95% CI, 1.09-1.53) and mental (OR 1.45; 95% CI, 1.23-1.72) health in midlife. CONCLUSIONS AND RELEVANCE: The findings of this cohort study suggest that extending the window of observation beyond childhood may reveal clear subtypes of atopic eczema based on patterns of disease activity. A newly identified subtype with increasing probability of activity in adulthood warrants additional attention given observed associations with poor self-reported health in midlife.

Association of Granuloma Annulare With Type 2 Diabetes, Hyperlipidemia, Autoimmune Disorders, and Hematologic Malignant Neoplasms.

IMPORTANCE: Although granuloma annulare (GA) has been associated with several other conditions, these studies have been limited by single-center designs and small sample sizes. OBJECTIVE: To evaluate whether there is an association between GA and type 2 diabetes, hyperlipidemia, autoimmune conditions, and hematologic malignant neoplasms, using a large population-based cohort study. DESIGN, SETTING, AND PARTICIPANTS: This retrospective cohort study conducted between January 1, 2016, and June 30, 2019, used deidentified data from the US Optum Clinformatics Data Mart Database. A total of 5137 patients with GA were matched by age and sex with up to 10 randomly selected controls (n = 51 169) with a diagnosis of a nevus or seborrheic keratosis. MAIN OUTCOMES AND MEASURES: Logistic regression was used to evaluate for potential associations between GA and diabetes, hyperlipidemia, autoimmune conditions, and hematologic malignant neoplasms. All analyses were adjusted for race/ethnicity, income, and educational level. RESULTS: This study included 5137 individuals with GA (3760 women [73.2%]; mean [SD] age, 57.7 [19.0] years) and 51 169 controls (37 456 women [73.2%]; mean [SD] age, 57.7 [19.0] years). Those with GA were more likely than controls to have baseline diabetes (1086 [21.1%] vs 6780 [13.3%]; adjusted odds ratio [aOR], 1.67; 95% CI, 1.55-1.80), hyperlipidemia (1669 [32.5%] vs 14 553 [28.4%]; aOR, 1.15; 95% CI, 1.08-1.23), hypothyroidism (727 [14.2%] vs 5780 [11.3%]; aOR, 1.24; 95% CI, 1.15-1.36), and rheumatoid arthritis (62 [1.2%] vs 441 [0.9%]; aOR, 1.34; 95% CI, 1.02-1.75). Those with GA were more likely to have incident diabetes (144 [2.8%] vs 1061 [2.1%]; aOR, 1.31; 95% CI, 1.10-1.57), hypothyroidism (41 [0.8%] vs 252 [0.5%]; aOR, 1.59; 95% CI, 1.14-2.22), systemic lupus erythematosus (21 [0.4%] vs 65 [0.1%]; aOR, 3.06; 95% CI, 1.86-5.01), and rheumatoid arthritis (26 [0.5%] vs 122 [0.2%]; aOR, 2.05; 95% CI, 1.34-3.13). There was no association between GA and an increased risk of hematologic malignant neoplasms. CONCLUSIONS AND RELEVANCE: This population-based cohort study identified associations between GA and baseline diabetes and hyperlipidemia as well as between GA and both baseline and incident autoimmune conditions. These findings suggest that diabetes and hyperlipidemia may be risk factors for the development of GA and that autoimmunity may be an important factor in the pathogenesis of GA.