Synthetic symmetry breaking and programmable multicellular structure formation.

During development, cells undergo symmetry breaking into differentiated subpopulations that self-organize into complex structures.1,2,3,4,5 However, few tools exist to recapitulate these behaviors in a controllable and coupled manner.6,7,8,9 Here, we engineer a stochastic recombinase genetic switch tunable by small molecules to induce programmable symmetry breaking, commitment to downstream cell fates, and morphological self-organization. Inducers determine commitment probabilities, generating tunable subpopulations as a function of inducer dosage. We use this switch to control the cell-cell adhesion properties of cells committed to each fate.10,11 We generate a wide variety of 3D morphologies from a monoclonal population and develop a computational model showing high concordance with experimental results, yielding new quantitative insights into the relationship between cell-cell adhesion strengths and downstream morphologies. We expect that programmable symmetry breaking, generating precise and tunable subpopulation ratios and coupled to structure formation, will serve as an integral component of the toolbox for complex tissue and organoid engineering.

Retinal Ischemic Perivascular Lesions in Individuals With Atrial Fibrillation.

Background We previously demonstrated that retinal ischemic perivascular lesions (RIPLs), which are indicative of ischemia in the middle retina, may be a biomarker of ischemic cardiovascular disease. In this study, we sought to determine the relationship between RIPLs and atrial fibrillation, a common source of cardiac emboli. Methods and Results In this case-control study, we identified individuals between the ages of 50 and 90 years who had undergone macular spectral domain optical coherence tomography imaging. Individuals with atrial fibrillation were identified, and age- and sex-matched individuals from the same pool, but without a diagnosis of atrial fibrillation, were selected as controls. Spectral domain optical coherence tomography scans were reviewed by 3 independent and masked observers for presence of RIPLs. The relationship between RIPLs and atrial fibrillation was analyzed using multivariable logistic regression models. There were 106 and 91 subjects with and without atrial fibrillation, respectively. The percentage of subjects with RIPLs was higher in the atrial fibrillation group compared with the control group (57.5% versus 37.4%; P=0.005). After adjusting for age, sex, smoking history, hypertension, diabetes, coronary artery disease, carotid stenosis, stroke, and myocardial infarction, the presence of RIPLs was significantly associated with atrial fibrillation, with an odds ratio of 1.91 (95% CI, 1.01-3.59). Conclusions RIPLs are significantly associated with atrial fibrillation, independent of underlying ischemic heart disease or cardiovascular risk factors. This association may inform the diagnostic cardiovascular workup for individuals with RIPLs incidentally detected on optical coherence tomography scan of the macula.

Performance of Generative Large Language Models on Ophthalmology Board-Style Questions.

PURPOSE: To investigate the ability of generative artificial intelligence models to answer ophthalmology board-style questions. DESIGN: Experimental study. METHODS: This study evaluated 3 large language models (LLMs) with chat interfaces, Bing Chat (Microsoft) and ChatGPT 3.5 and 4.0 (OpenAI), using 250 questions from the Basic Science and Clinical Science Self-Assessment Program. Although ChatGPT is trained on information last updated in 2021, Bing Chat incorporates a more recently indexed internet search to generate its answers. Performance was compared with human respondents. Questions were categorized by complexity and patient care phase, and instances of information fabrication or nonlogical reasoning were documented. MAIN OUTCOME MEASURES: Primary outcome was response accuracy. Secondary outcomes were performance in question subcategories and hallucination frequency. RESULTS: Human respondents had an average accuracy of 72.2%. ChatGPT-3.5 scored the lowest (58.8%), whereas ChatGPT-4.0 (71.6%) and Bing Chat (71.2%) performed comparably. ChatGPT-4.0 excelled in workup-type questions (odds ratio [OR], 3.89, 95% CI, 1.19-14.73, P = .03) compared with diagnostic questions, but struggled with image interpretation (OR, 0.14, 95% CI, 0.05-0.33, P < .01) when compared with single-step reasoning questions. Against single-step questions, Bing Chat also faced difficulties with image interpretation (OR, 0.18, 95% CI, 0.08-0.44, P < .01) and multi-step reasoning (OR, 0.30, 95% CI, 0.11-0.84, P = .02). ChatGPT-3.5 had the highest rate of hallucinations and nonlogical reasoning (42.4%), followed by ChatGPT-4.0 (18.0%) and Bing Chat (25.6%). CONCLUSIONS: LLMs (particularly ChatGPT-4.0 and Bing Chat) can perform similarly with human respondents answering questions from the Basic Science and Clinical Science Self-Assessment Program. The frequency of hallucinations and nonlogical reasoning suggests room for improvement in the performance of conversational agents in the medical domain.

Dacryocystitis in a patient with Samter's triad.

Samter's triad, also known as aspirin-exacerbated respiratory disease, is characterized by nasal polyposis, bronchial asthma, and aspirin intolerance. Here, we present a case of a 36-year-old woman with a history of Samter's triad and recurrent dacryocystitis. After combined dacryocystorhinostomy and endoscopic sinus surgery, pathological specimens of the lacrimal sac showed respiratory fibrosis with chronic inflammation and eosinophilic infiltration. Our case demonstrates that Samter's triad is a potential etiology for inflammatory nasolacrimal duct obstruction.

Analyzing changes to U.S. municipal heat response plans during the COVID-19 pandemic.

Extreme heat events are the deadliest weather-related event in the United States. Cities throughout the United States have worked to develop heat adaptation strategies to limit the impact of extreme heat on vulnerable populations. However, the COVID-19 pandemic presented unprecedented challenges to local governments. This paper provides a preliminary review of strategies and interventions used to manage compound COVID-19-extreme heat events in the 25 most populous cities of the United States. Heat adaptation strategies employed prior to the COVID-19 pandemic were not adequate to meet during the co-occurring compound hazard of COVID-19-EHE. Long-term climate-adaptation strategies will require leveraging physical, financial, and community resources across multiple city departments to meet the needs of compound hazards, such as COVID-19 and extreme heat.

3D Attention M-net for Short-axis Left Ventricular Myocardium Segmentation in Mice MR cardiac Images.

Small rodent cardiac magnetic resonance imaging (MRI) plays an important role in preclinical models of cardiac disease. Accurate myocardial boundaries delineation is crucial to most morphological and functional analysis in rodent cardiac MRIs. However, rodent cardiac MRIs, due to animal's small cardiac volume and high heart rate, are usually acquired with sub-optimal resolution and low signal-to-noise ratio (SNR). These rodent cardiac MRIs can also suffer from signal loss due to the intra-voxel dephasing. These factors make automatic myocardial segmentation challenging. Manual contouring could be applied to label myocardial boundaries but it is usually laborious, time consuming, and not systematically objective. In this study, we present a deep learning approach based on 3D attention M-net to perform automatic segmentation of left ventricular myocardium. In the deep learning architecture, we use dual spatial-channel attention gates between encoder and decoder along with multi-scale feature fusion path after decoder. Attention gates enable networks to focus on relevant spatial information and channel features to improve segmentation performance. A distance derived loss term, besides general dice loss and binary cross entropy loss, was also introduced to our hybrid loss functions to refine segmentation contours. The proposed model outperforms other generic models, like U-Net and FCN, in major segmentation metrics including the dice score (0.9072), Jaccard index (0.8307) and Hausdorff distance (3.1754 pixels), which are comparable to the results achieved by state-of-the-art models on human cardiac ACDC17 datasets.Clinical relevance Small rodent cardiac MRI is routinely used to probe the effect of individual genes or groups of genes on the etiology of a large number of cardiovascular diseases. An automatic myocardium segmentation algorithm specifically designed for these data can enhance accuracy and reproducibility of cardiac structure and function analysis.

Reactivation of Pulmonary Tuberculosis in a Patient With COVID-19: Case Report and Review of Literature.

Given COVID-19 rise in populations with high burden of tuberculosis infection, the interplay between COVID-19 and tuberculosis reactivation needs further investigation. We report a case of a 64-year-old man who developed acute respiratory distress syndrome due to severe COVID-19 infection. He was managed with intubation, prone-position mechanical ventilation, inhaled nitric oxide, and methylprednisolone 40 mg intravenous twice daily for 5 days. He developed unexplained persistent fever and leukocytosis that failed to respond to empiric broad-spectrum antibacterial, antifungal agents, and a 3-day course of intravenous methylprednisolone 1000 mg for possible usual interstitial pneumonitis. His endotracheal aspiration samples tested positive for Mycobacterium tuberculosis, and antituberculosis regimen was started. The patient died as result of decision to withdraw life support. This report establishes the clinical picture of a tuberculosis reactivation in a COVID-19 patient. The complex interaction between COVID-19, steroids, and tuberculosis is a clinical dilemma of great significance.

Relationship among state reopening policies, health outcomes and economic recovery through first wave of the COVID-19 pandemic in the U.S.

State governments in the U.S. have been facing difficult decisions involving tradeoffs between economic and health-related outcomes during the COVID-19 pandemic. Despite evidence of the effectiveness of government-mandated restrictions mitigating the spread of contagion, these orders are stigmatized due to undesirable economic consequences. This tradeoff resulted in state governments employing mandates at widely different ways. We compare the different policies states implemented during periods of restriction ("lockdown") and reopening with indicators of COVID-19 spread and consumer card spending at each state during the first "wave" of the pandemic in the U.S. between March and August 2020. We find that while some states enacted reopening decisions when the incidence rate of COVID-19 was minimal or sustained in its relative decline, other states relaxed socioeconomic restrictions near their highest incidence and prevalence rates experienced so far. Nevertheless, all states experienced similar trends in consumer card spending recovery, which was strongly correlated with reopening policies following the lockdowns and relatively independent from COVID-19 incidence rates at the time. Our findings suggest that consumer card spending patterns can be attributed to government mandates rather than COVID-19 incidence in the states. We estimate the recovery in states that reopened in late April was more than the recovery in states that did not reopen in the same period- 15% for consumer card spending and 18% for spending by high income households. This result highlights the important role of state policies in minimizing health impacts while promoting economic recovery and helps planning effective interventions in subsequent waves and immunization efforts.

Mobile Diabetes Telemedicine Clinics for Aboriginal First Nation People With Reported Diabetes in British Columbia.

OBJECTIVES: Our aim in this study was to assess the impact of the Mobile Diabetes Telemedicine Clinic, which serves First Nations communities in British Columbia, on clients' with diabetes condition and management. METHODS: A travelling team visits approximately 120 sites annually. Assessment of persons with diabetes includes interview, physical exam, point-of-care laboratory (glycated hemoglobin, blood glucose, lipid profile, kidney profile) and retinal fundus photographs. Nurses provide education and lifestyle, medication and wellness recommendations. The endocrinologist reviews records and provides further recommendations to primary care providers. To assess the impact at second and later visits, compared with the immediately preceding visit, we measured mean changes in body weight, glycated hemoglobin, urinary albumin:creatinine ratio and estimated glomerular filtration rate, as well as changes in proportions of clients meeting targets for blood pressure, low-density lipoprotein cholesterol, medications, smoking and physical activity. RESULTS: From 2012 to 2018, a total of 3,045 visits were completed by 1,056 clients with diabetes who attended on at least 2 occasions. Mean time since the preceding visit was 1.6 years. Mean change (after vs before) in glycated hemoglobin was 0.06 (95% confidence limit, -0.03 to 0.14), body weight 0.0 kg (-0.2 to 0.2), albumin:creatinine ratio 1.31 mg/mmol (0.27 to 2.35) and estimated glomerular filtration rate -4.8 mL/min (-6.2 to -3.4). The proportion of clients meeting both blood pressure targets (systolic <130 mmHg and diastolic <80 mmHg) increased from 25% at first visit to 33% at the second and 32% at the third or later visits (p<0.001, chi-square test). The proportion of those with low-density lipoprotein cholesterol of <2.0 mmol/L increased from 56% to 62% at the second visit and 69% at the third or later visits (p<0.001). The proportion of those taking renin-angiotensin-aldosterone system inhibitors or other antihypertensive agents and statins increased (p<0.001), and proportions decreased for smoking (p<0.001) and exercising ≥60 min/week (p=0.002). CONCLUSIONS: Weight and diabetic control were stabilized. Most management practices showed improvement.

Nerve cuff electrode pressure estimation via electrical impedance measurement.

OBJECTIVE: Implantable neuromodulation devices that have cuff electrodes are known to exert mechanical pressure on the target nerves. The amount of pressure exerted by cuff enclosures is one of the key determinants of physiological safety of these devices since excess pressures can cause neural damage. Because direct measurements of pressure on a nerve are challenging, the current cuff design approaches rely heavily on theoretical models or numerical computations for pressure predictions. An experimental approach to test these devices for pressure can complement existing theoretical models and can also serve as a quality control step to screen cuff electrode designs before implantation. APPROACH: We hypothesize that the pressure exerted on a nerve by a cuff can be estimated by measuring the resulting changes to the nerve's electrical impedance. MAIN RESULTS: We investigated ten 1 cm-long explanted rat sciatic nerves: five that were used within an hour after surgery, and five after 50 h of storage in physiological saline. For each experiment we applied variable pressure on the nerve ex vivo and measured the resulting changes in its impedance. We found a strong correlation between the external pressure on the nerve and its impedance and generated a pressure-impedance calibration curve. At the upper limit of physiologically safe pressure, the nerve impedance increased by ~2 kΩ, whereas, a rise of ~3 kΩ corresponded to pressure value that onsets irreversible nerve damage. SIGNIFICANCE: As a proof-of-concept, we used this protocol to generate a pressure-impedance calibration curve for a monkey tibial nerve and estimated pressure exerted by a commercial silicone cuff electrode on the explanted nerve. This single-point measurement was in an agreement with an independent estimate of the pressure measured using a mechanical pull test within 3 mmHg.

Correction: Hospitalizations due to unintentional transport injuries among Aboriginal population of British Columbia, Canada: Incidence, changes over time and ecological analysis of risk markers.

[This corrects the article DOI: 10.1371/journal.pone.0191384.].

Hospitalizations due to unintentional transport injuries among Aboriginal population of British Columbia, Canada: Incidence, changes over time and ecological analysis of risk markers.

BACKGROUND: Worldwide, Indigenous people have disproportionately higher rates of transport injuries. We examined disparities in injury-related hospitalizations resulting from transport incidents for three population groups in British Columbia (BC): total population, Aboriginal off-reserve, and Aboriginal on-reserve populations. We also examined sociodemographic, geographic and ethnic risk markers for disparities. METHODS: We identified Aboriginal people through BC's universal health care insurance plan insurance premium group and birth and death record notations. We calculated crude incidence rate and Standardized Relative Risk (SRR) of hospitalization for unintentional transport injury, standardized for age, gender and Health Service Delivery Area (HSDA), relative to the total population of BC. We tested hypothesized associations of geographic, socio-economic, and employment-related characteristics of Aboriginal communities with SRR of transport injury by multivariable linear regression. RESULTS: During the period 1991-2010, the SRR for the off-reserve Aboriginal population was 1.77 (95% CI: 1.71 to 1.83); and 2.00 (95% CI: 1.93 to 2.07) among those living on-reserve. Decline in crude rate and SRRs was observed over this period among both the Aboriginal and total populations of BC, but was proportionally greater among the Aboriginal population. The best-fitting multivariable risk marker model was an excellent fit (R2 = 0.912, p<0.001), predicted SRRs very close to observed values, and retained the following terms: urban residence, population per room, proportion of the population with a high school certificate, proportion of the population employed; and multiplicative interactions of Aboriginal ethnicity with population per room and proportion of the population employed. CONCLUSIONS: Disparities in risk of hospitalization due to unintentional transport injury have narrowed. Aboriginal ethnicity modifies the effects of socioeconomic risk factors. Continued improvement of socioeconomic conditions and implementation of culturally relevant injury prevention interventions are needed.

Iatrogenic Injury among the Aboriginal and Total Populations of British Columbia, Canada, 1991-2010: Inequities Associated with Ethnicity and Socioeconomic Status.

PURPOSE: Measure population health impact, and socioeconomic, geographic, and ethnic predictors of iatrogenic injury. METHODS: Within three groups (total population, Aboriginal off-reserve, and Aboriginal on-reserve) in each of 16 Health Service Delivery Areas (HSDAs) of British Columbia, Canada we calculated crude incidence and Standardized Relative Risk (SRR) of hospitalization for iatrogenic injury. We tested hypothesized associations between HSDA census characteristics and SRR, by multivariable regression. RESULTS: Among hospitalizations due to any injury, 22.2% were iatrogenic. Crude rate of iatrogenic injury hospitalization was 20.4 per 10,000 person-years. Aboriginal rate was 24.4 per 10,000 and SRR was 1.57 (1.76 among females, 1.38 among males). Non-metropolitan HSDAs had higher SRRs. The best-fitting regression model was an excellent fit (R=0.836, p<.001) and included education, income, house needs major repairs, population per room, and Aboriginal ethnicity. CONCLUSIONS: Iatrogenic injury has significant population health impact. Aboriginal people, especially females, have higher risk. Ethnicity and socioeconomic factors explain regional disparities.

Intentional injury among the indigenous and total populations in British Columbia, Canada: trends over time and ecological analyses of risk.

BACKGROUND: Our objective was to explore intentional injury disparity between Indigenous populations and the total population in the province of British Columbia (BC), Canada. We focus on hospitalizations, including both self-inflicted injuries and injuries inflicted by others. METHODS: We used data from BC's universal health care insurance plan, 1991 to 2010, linked to Vital Statistics databases. Indigenous people were identified through the insurance premium group, and birth and death records. Place of residence was identified through postal code. We calculated crude hospitalization incidence rates and the Standardized Relative Risk (SRR) of hospitalization, standardized by gender, 5-year age group, and Health Service Delivery Area (HSDA). With HSDA populations as the units of observation, linear regression was used to test hypothesized associations of Indigenous ethnicity, geographic, and socio-economic characteristics with SRR of injury. RESULTS: During the period 1991-2010, the crude rate of hospitalization for intentional injuries was 8.4 per 10,000 person-years (95% confidence interval (CI): 8.3 to 8.5) for the total BC population, compared to 45.3 per 10,000 (95% CI: 44.5 to 46.1) for the Indigenous population. For both populations, risk declined over the period for injuries self-inflicted and inflicted by others. The linear regression model predicts that the off-reserve Indigenous population will have SRR of intentional injury 3.98 greater, and the on-reserve Indigenous population 4.17, greater than the total population. The final model was an excellent fit (R2 = 0.912, F = 177.632, p < 0.001), and found that three variables - occupational risk, high school diploma, and university degree - each provide independent effects when interacting multiplicatively with Indigenous ethnicity. CONCLUSIONS: The observation of substantially declining rates of intentional injury for both the Indigenous and total BC populations is off-set by the high disparity in risk between the two populations, which will likely continue until Canada reduces disparity with respect to discriminatory practices, and physical, social, and economic conditions.

Risk of Hospitalization Due to Unintentional Fall Injury in British Columbia, Canada, 1999-2008: Ecological Associations with Socioeconomic Status, Geographic Place, and Aboriginal Ethnicity.

BACKGROUND: Aboriginal people in British Columbia (BC), especially those residing on Indian reserves, have higher risk of unintentional fall injury than the general population. We test the hypothesis that the disparities are attributable to a combination of socioeconomic status, geographic place, and Aboriginal ethnicity. METHODS: Within each of 16 Health Service Delivery Areas in BC, we identified three population groups: total population, Aboriginal off-reserve, and Aboriginal on-reserve. We calculated age and gender-standardized relative risks (SRR) of hospitalization due to unintentional fall injury (relative to the total population of BC), during time periods 1999-2003 and 2004-2008, and we obtained custom data from the 2001 and 2006 censuses (long form), describing income, education, employment, housing, proportions of urban and rural dwellers, and prevalence of Aboriginal ethnicity. We studied association of census characteristics with SRR of fall injury, by multivariable linear regression. RESULTS: The best-fitting model was an excellent fit (R 2 = 0.854, p < 0.001) and predicted SRRs very close to observed values for the total, Aboriginal off-reserve, and Aboriginal on-reserve populations of BC. After stepwise regression, the following terms remained: population per room, urban residence, labor force participation, income per capita, and multiplicative interactions of Aboriginal ethnicity with population per room and labor force participation. CONCLUSIONS: The disparities are predictable by the hypothesized risk markers. Aboriginal ethnicity is not an independent risk marker: it modifies the effects of socioeconomic factors. Closing the gap in fall injury risk between the general and Aboriginal populations is likely achievable by closing the gaps in socioeconomic conditions.

Injuries to Aboriginal populations living on- and off-reserve in metropolitan and non-metropolitan areas in British Columbia, Canada: Incidence and trends, 1986-2010.

BACKGROUND: Disparities in injury rates between Aboriginal and non-Aboriginal populations in British Columbia (BC) are well established. Information regarding the influence of residence on disparities is scarce. We sought to fill these gaps by examining hospitalization rates for all injuries, unintentional injuries and intentional injuries across 24 years among i) Aboriginal and total populations; ii) populations living in metropolitan and non-metropolitan areas; and iii) Aboriginal populations living on- and off-reserve. METHODS: We used data spanning 1986 through 2010 from BC's universal health care insurance plan, linked to vital statistics databases. Aboriginal people were identified by insurance premium group and birth and death record notations, and their residence was determined by postal code. "On-reserve" residence was established by postal code areas associated with an Indian reserve or settlement. Health Service Delivery Areas (HSDAs) were classified as "metropolitan" if they contained a population of at least 100,000 with a density of 400 or more people per square kilometre. We calculated the crude hospitalization incidence rate and the Standardized Relative Risk (SRR) of hospitalization due to injury standardizing by gender, 5-year age group, and HSDA. We assessed cumulative change in SRR over time as the relative change between the first and last years of the observation period. RESULTS: Aboriginal metropolitan populations living off-reserve had the lowest SRR of injury (2.0), but this was 2.3 times greater than the general British Columbia metropolitan population (0.86). For intentional injuries, Aboriginal populations living on-reserve in non-metropolitan areas were at 5.9 times greater risk than the total BC population. In general, the largest injury disparities were evident for Aboriginal non-metropolitan populations living on-reserve (SRR 3.0); 2.5 times greater than the general BC non-metropolitan population (1.2). Time trends indicated decreasing disparities, with Aboriginal non-metropolitan populations experiencing the largest declines in injury rates. CONCLUSIONS: Metropolitan/non-metropolitan residence appears to be a more important predictor than on/off-reserve residence for all injuries and unintentional injuries, and the relationship was even more pronounced for intentional injuries. The persistent disparities highlight the need for culturally sensitive and geographically relevant injury prevention approaches.

Agreement of Point-of-Care Capillary Glycated Hemoglobin Levels with Conventional Screening Tests for Diabetes Mellitus in a Canadian First Nations Population.

OBJECTIVES: 1) How closely do capillary glycated hemoglobin (A1C) levels agree with venous A1C levels? 2) How well do venous A1C levels agree with plasma glucose for diagnosis of diabetes in this population? METHODS: The Seabird Island mobile diabetes clinic screened people not known to have diabetes by using finger-prick capillary A1C levels with point-of-care analysis according to the Siemens/Bayer DCA 2000 system. Clients then went to a clinical laboratory for confirmatory testing for venous A1C levels, fasting plasma glucose (FPG) and plasma glucose 2 hours after 75 g oral glucose load (2hPG). A reference laboratory compared the DCA 2000 and the clinical laboratory's Roche Integra 800CTS system to the National Glycohemoglobin Standardization Program Diabetes Control and Complications Trial (DCCT) reference. RESULTS: 1) In the reference laboratory, DCA 2000 and Integra 800CTS both agreed very closely with the DCCT standard. In the field, capillary glycated hemoglobin percent (A1C) % was biased, underestimating venous A1C % by a mean of 0.19 (p<0.001). The margin of error of bias-adjusted capillary A1C % was ±0.36 for 95% of the time, compared to ±0.27 for venous A1C%. 2) By linear regression, we found FPG 7.0 mmol/L and 2hPG 11.1 mmol/L predicted mean venous A1C levels very close to 6.5%, with no significant bias. CONCLUSIONS: Point-of-care capillary A1C did not perform as well in the field as in the laboratory, but the bias is correctible, and the margin of error is small enough that the test is clinically useful. In this population, venous A1C levels ≥6.5% agree closely with the FPG and 2hPG thresholds to diagnose diabetes; ethnic-specific adjustment of the venous A1C threshold is not necessary.

Primary care visits due to injuries among the Aboriginal off-reserve population of British Columbia, Canada, 1991-2010.

BACKGROUND: Aboriginal people in British Columbia (BC) have higher injury incidence than the general population. This report describes variability in visits to primary care due to injury, among injury categories, time periods, geographies, and demographic groups. METHODS: We used BC's universal health care insurance plan as a population registry, linked to practitioner payment and vital statistics databases. We identified Aboriginal people by insurance premium group and birth and death record notations. Within that population we identified those residing off-reserve according to postal code. We calculated crude incidence and Standardized Relative Risk (SRR) of primary care visit due to injury, standardized for age, gender and Health Service Delivery Area (HSDA), relative to the total population of BC. RESULTS: During 1991 through 2010, the crude rate of primary care visit due to injury in BC was 3172 per 10,000 person-years. The Aboriginal off-reserve rate was 4291 per 10,000 and SRR was 1.41 (95 % confidence interval: 1.41 to 1.42). Northern and non-metropolitan HSDAs had higher SRRs, within both total BC and Aboriginal off-reserve populations. In every age and gender category, the HSDA-standardized SRR was higher among the Aboriginal off-reserve than among the total population. For all injuries combined, and for the categories of trauma, poisoning, and burn, between 1991 and 2010, crude rates and SRRs declined substantially, but proportionally more rapidly among the Aboriginal off-reserve population, so the gap between the Aboriginal off-reserve and total populations is narrowing, particularly among metropolitan residents. CONCLUSIONS: These findings corroborate our previous reports regarding hospitalizations due to injury, suggesting that our observations reflect real disparities and changes in the underlying incidence of injury, and are not merely artefacts related to health care utilization.

Injury hospitalizations due to unintentional falls among the Aboriginal population of British Columbia, Canada: incidence, changes over time, and ecological analysis of risk markers, 1991-2010.

BACKGROUND: Aboriginal people in British Columbia (BC) have higher injury incidence than the general population. Our project describes variability among injury categories, time periods, and geographic, demographic and socio-economic groups. This report focuses on unintentional falls. METHODS: We used BC's universal health care insurance plan as a population registry, linked to hospital separation and vital statistics databases. We identified Aboriginal people by insurance premium group and birth and death record notations. We identified residents of specific Aboriginal communities by postal code. We calculated crude incidence and Standardized Relative Risk (SRR) of hospitalization for unintentional fall injury, standardized for age, gender and Health Service Delivery Area (HSDA), relative to the total population of BC. We tested hypothesized associations of geographic, socio-economic, and employment-related characteristics with community SRR of injury by linear regression. RESULTS: During 1991 through 2010, the crude rate of hospitalization for unintentional fall injury in BC was 33.6 per 10,000 person-years. The Aboriginal rate was 49.9 per 10,000 and SRR was 1.89 (95% confidence interval 1.85-1.94). Among those living on reserves SRR was 2.00 (95% CI 1.93-2.07). Northern and non-urban HSDAs had higher SRRs, within both total and Aboriginal populations. In every age and gender category, the HSDA-standardized SRR was higher among the Aboriginal than among the total population. Between 1991 and 2010, crude rates and SRRs declined substantially, but proportionally more among the Aboriginal population, so the gap between the Aboriginal and total population is narrowing, particularly among females and older adults. These community characteristics were associated with higher risk: lower income, lower educational level, worse housing conditions, and more hazardous types of employment. CONCLUSIONS: Over the years, as socio-economic conditions improve, risk of hospitalization due to unintentional fall injury has declined among the Aboriginal population. Women and older adults have benefited more.