The Superblock model: A review of an innovative urban model for sustainability, liveability, health and well-being.

INTRODUCTION: Current urban and transport planning practices have significant negative health, environmental, social and economic impacts in most cities. New urban development models and policies are needed to reduce these negative impacts. The Superblock model is one such innovative urban model that can significantly reduce these negative impacts through reshaping public spaces into more diverse uses such as increase in green space, infrastructure supporting social contacts and physical activity, and through prioritization of active mobility and public transport, thereby reducing air pollution, noise and urban heat island effects. This paper reviews key aspects of the Superblock model, its implementation and initial evaluations in Barcelona and the potential international uptake of the model in Europe and globally, focusing on environmental, climate, lifestyle, liveability and health aspects. METHODS: We used a narrative meta-review approach and PubMed and Google scholar databases were searched using specific terms. RESULTS: The implementation of the Super block model in Barcelona is slow, but with initial improvement in, for example, environmental, lifestyle, liveability and health indicators, although not so consistently. When applied on a large scale, the implementation of the Superblock model is not only likely to result in better environmental conditions, health and wellbeing, but can also contribute to the fight against the climate crisis. There is a need for further expansion of the program and further evaluation of its impacts and answers to related concerns, such as environmental equity and gentrification, traffic and related environmental exposure displacement. The implementation of the Superblock model gained a growing international reputation and variations of it are being planned or implemented in cities worldwide. Initial modelling exercises showed that it could be implemented in large parts of many cities. CONCLUSION: The Superblock model is an innovative urban model that addresses environmental, climate, liveability and health concerns in cities. Adapted versions of the Barcelona Superblock model are being implemented in cities around Europe and further implementation, monitoring and evaluation are encouraged. The Superblock model can be considered an important public health intervention that will reduce mortality and morbidity and generate cost savings for health and other sectors.

The Health-Related and Learning Performance Effects of Air Pollution and Other Urban-Related Environmental Factors on School-Age Children and Adolescents-A Scoping Review of Systematic Reviews.

PURPOSE OF REVIEW: This scoping review aims to assess the impact of air pollution, traffic noise, heat, and green and blue space exposures on the physical and cognitive development of school-age children and adolescents. While existing evidence indicates adverse effects of transport-related exposures on their health, a comprehensive scoping review is necessary to consolidate findings on various urban environmental exposures' effects on children's development. RECENT FINDINGS: There is consistent evidence on how air pollution negatively affects children's cognitive and respiratory health and learning performance, increasing their susceptibility to diseases in their adult life. Scientific evidence on heat and traffic noise, while less researched, indicates that they negatively affect children's health. On the contrary, green space exposure seems to benefit or mitigate these adverse effects, suggesting a potential strategy to promote children's cognitive and physical development in urban settings. This review underscores the substantial impact of urban exposures on the physical and mental development of children and adolescents. It highlights adverse health effects that can extend into adulthood, affecting academic opportunities and well-being beyond health. While acknowledging the necessity for more research on the mechanisms of air pollution effects and associations with heat and noise exposure, the review advocates prioritizing policy changes and urban planning interventions. This includes minimizing air pollution and traffic noise while enhancing urban vegetation, particularly in school environments, to ensure the healthy development of children and promote lifelong health.

Adapting Schools to Climate Change with Green, Blue, and Grey Measures in Barcelona: Study Protocol of a Mixed-Method Evaluation.

Under the framework of the Urban Innovative Actions program of the European Commission, in 2020, 11 primary schools in Barcelona were transformed into climate shelters by implementing green, blue, and grey measures. Schoolyards were also opened to the local community to be used during non-school periods. Here we present the study protocol of a mixed-method approach to evaluate the effectiveness of the interventions in terms of improving environmental quality and health for users. We evaluated school level through the following: (1) quantitative pre-post quasi-experimental study, and (2) qualitative evaluation. The quantitative study included measures of (a) environmental variables (collected via low-cost and non-low-cost sensors), (b) students' health and well-being (collected via health questionnaires, attention levels test, and systematic observations), and (c) teachers' health and well-being (collected via thermal comfort measurements and health questionnaires). The qualitative methods evaluated the perceptions about the effects of the interventions among students (using Photovoice) and teachers (through focus groups). The impact of the interventions was assessed at community level during summer non-school periods through a spontaneous ethnographic approach. Data collection started in August 2019 and ended in July 2022. The evaluation provides the opportunity to identify those solutions that worked and those that need to be improved for future experiences, as well as improve the evaluation methodology and replication for these kinds of interventions.

Public Health-Led Insights on Electric Micro-mobility Adoption and Use: a Scoping Review.

The advent of electric micro-mobility (EMM) has transformed the urban mobility landscape, with projections indicating a 5-10% increase in its modal share in European cities by 2030. In this scoping review, we aimed to comprehensively examine the key determinants of EMM adoption and usage from a public health perspective. Sixty-seven articles were included in the analysis, primarily covering e-bikes and e-scooters. The determinants were categorised into two broad categories: (1) contextual determinants that encompass enabling and hindering factors related to legal frameworks, transportation systems and infrastructure, and technology, and (2) individual-level determinants that pertain to intrinsic motivations and deterrents of individuals. Our findings reveal that EMM vehicles are widely perceived as a cost-effective, flexible, ad hoc, and fast mode of transportation within urban areas, augmenting accessibility and connectivity. Additionally, the lightweight, foldable, and transportable nature of these vehicles is highly appreciated by users. However, several barriers have also been identified, including inadequate infrastructure and end-of-trip facilities, limited capability to traverse diverse terrains and trip scenarios, acquisition and maintenance costs, limited carrying capacities, technical failures, and accident risks. Our results suggest that the interplay of contextual enablers and barriers and personal motivations and deterrents drive the emergence, adoption, and usage of EMM. Hence, a comprehensive understanding of both contextual and individual-level determinants is crucial for ensuring a sustainable and healthy uptake of EMM.

An urban green space intervention with benefits for mental health: A health impact assessment of the Barcelona "Eixos Verds" Plan.

BACKGROUND: Mental health disorders account for over 30% of the global burden of disease. There is a positive association between green space exposure and better mental health, and therefore urban greening can be an effective public health tool. Barcelona is a compact city with one of the highest population and traffic densities in Europe, with limited green spaces. Under the umbrella of the Superblock model, the Barcelona City council is implementing the Eixos Verds Plan for extensive street greening. We estimated the potential mental health benefits of this plan. METHODS: We performed a quantitative health impact assessment at the Barcelona grid-cell level (n = 1,096). We compared the baseline green space situation (2015) with the proposed plan and translated the increase in green space into a) percentage of green area (%GA) and b) NDVI. We combined exposure data with Barcelona-specific mental health risk estimates, adult population (n = 1,235,375), and mental health data, and calculated preventable cases. FINDINGS: Under the Eixos Verds Plan, we estimated an average increase of 5·67 %GA (range: 0·00% - 15·77%) and 0·059 NDVI (range: 0·000 - 0·312). We estimated that with the Eixos Verds Plan implementation, 31,353 (95%CI: 18,126-42,882) cases of self-perceived poor mental health (14·03% of total), 16,800 (95%CI: 6828-25,700) visits to mental health specialists (13·37% of total), 13,375 (95%CI: 6107-19,184) cases of antidepressant use (13·37% of total), and 9476 (95%CI: 802-16,391) cases of tranquilliser/ sedative use (8·11% of total) could be prevented annually, along corresponding to over 45 M € annual savings in mental health costs annually. INTERPRETATION: Our results highlight the importance of urban greening as a public health tool to improve mental health in cities. Similar results for green interventions in other cities could be expected.

Impacts of changes in environmental exposures and health behaviours due to the COVID-19 pandemic on cardiovascular and mental health: A comparison of Barcelona, Vienna, and Stockholm.

Responses to COVID-19 altered environmental exposures and health behaviours associated with non-communicable diseases. We aimed to (1) quantify changes in nitrogen dioxide (NO2), noise, physical activity, and greenspace visits associated with COVID-19 policies in the spring of 2020 in Barcelona (Spain), Vienna (Austria), and Stockholm (Sweden), and (2) estimated the number of additional and prevented diagnoses of myocardial infarction (MI), stroke, depression, and anxiety based on these changes. We calculated differences in NO2, noise, physical activity, and greenspace visits between pre-pandemic (baseline) and pandemic (counterfactual) levels. With two counterfactual scenarios, we distinguished between Acute Period (March 15th - April 26th, 2020) and Deconfinement Period (May 2nd - June 30th, 2020) assuming counterfactual scenarios were extended for 12 months. Relative risks for each exposure difference were estimated with exposure-risk functions. In the Acute Period, reductions in NO2 (range of change from -16.9 µg/m3 to -1.1 µg/m3), noise (from -5 dB(A) to -2 dB(A)), physical activity (from -659 MET*min/wk to -183 MET*min/wk) and greenspace visits (from -20.2 h/m to 1.1 h/m) were largest in Barcelona and smallest in Stockholm. In the Deconfinement Period, NO2 (from -13.9 µg/m3 to -3.1 µg/m3), noise (from -3 dB(A) to -1 dB(A)), and physical activity levels (from -524 MET*min/wk to -83 MET*min/wk) remained below pre-pandemic levels in all cities. Greatest impacts were caused by physical activity reductions. If physical activity levels in Barcelona remained at Acute Period levels, increases in annual diagnoses for MI (mean: 572 (95% CI: 224, 943)), stroke (585 (6, 1156)), depression (7903 (5202, 10,936)), and anxiety (16,677 (926, 27,002)) would be anticipated. To decrease cardiovascular and mental health impacts, reductions in NO2 and noise from the first COVID-19 surge should be sustained, but without reducing physical activity. Focusing on cities' connectivity that promotes active transportation and reduces motor vehicle use assists in achieving this goal.

Study protocol of the European Urban Burden of Disease Project: a health impact assessment study.

INTRODUCTION: Cities have long been known to be society's predominant engine of innovation and wealth creation, yet they are also hotspots of pollution and disease partly due to current urban and transport practices. The aim of the European Urban Burden of Disease project is to evaluate the health burden and its determinants related to current and future potential urban and transport planning practices and related exposures in European cities and make this evidence available for policy and decision making for healthy and sustainable futures. METHODS AND ANALYSIS: Drawing on an established comparative risk assessment methodology (ie, Urban and Transport Planning Health Impact Assessment) tool), in nearly 1000 European cities we will (1) quantify the health impacts of current urban and transport planning related exposures (eg, air pollution, noise, excess heat, lack of green space) (2) and evaluate the relationship between current levels of exposure, health impacts and city characteristics (eg, size, density, design, mobility) (3) rank and compare the cities based on exposure levels and the health impacts, (4) in a number of selected cities assess in-depth the linkages between urban and transport planning, environment, physical activity and health, and model the health impacts of alternative and realistic urban and transport planning scenarios, and, finally, (5) construct a healthy city index and set up an effective knowledge translation hub to generate impact in society and policy. ETHICS AND DISSEMINATION: All data to be used in the project are publicly available data and do not need ethics approval. We will request consent for personal data on opinions and views and create data agreements for those providing information on current and future urban and transport planning scenarios.For dissemination and to generate impact, we will create a knowledge translation hub with information tailored to various stakeholders.

Large-scale citizen science protocol provides high-resolution nitrogen dioxide values while enhancing community knowledge and collective action.

We present an already tested protocol from a large-scale air quality citizen science campaign (xAire, 725 measurements, see Ref. [1]). A broad partnership with 1,650 people from communities including 18 primary schools in Barcelona (Spain) provided the capacity to obtain unprecedented high-resolution NO2 levels. Communities followed the protocol to select measurement points and obtain NO2 levels from outdoor locations n=671, playgrounds n=31, and inside school buildings (primarily classrooms) n=23. Data was calibrated and annualized with concentration levels from the city´s automatic air quality monitoring reference stations [2].

Data set from large-scale citizen science provides high-resolution nitrogen dioxide values for enhancing community knowledge and collective action to related health issues.

Dataset from a large-scale air quality citizen science campaign is presented (xAire, 725 measurements, see Ref. [1]). A broad partnership with 1650 citizens from communities around 18 primary schools across Barcelona (Spain) provided the capacity to obtain unprecedented high-resolution NO2 levels which had in turn the capacity to provide an updated asthma Health Impact Assessment. Nitrogen dioxide levels being obtained in a 4-week period during February and March 2018 with Palmes' diffusion samplers are herein provided. Dataset includes NO2 levels from outdoor locations n=671, playgrounds n=31, and inside school buildings (mostly classrooms) n=23. Data was calibrated and annualized with concentration levels from automatic reference stations. It is shown that NO2 levels vary considerably with at some cases very high levels. Strong differences might also however be explained by the fact that ambient air pollution is reduced exponentially with distance from an emission source like traffic meaning that two samplers located about 100 m away can measure a tenfold difference concentration level.

Large-scale citizen science provides high-resolution nitrogen dioxide values and health impact while enhancing community knowledge and collective action.

We present outcomes from a large-scale air quality citizen science campaign (xAire, 725 measurements) to demonstrate its positive contribution in the interplay between advances in exposure assessment and developments in policy or collective action. A broad partnership with 1,650 people from communities around 18 primary schools across Barcelona provided the capacity to obtain unprecedented high-resolution NO2 levels and an updated asthma Health Impact Assessment. It is shown that NO2 levels vary considerably with at some cases very high levels. More than a 1,000 new cases of childhood asthma could be prevented each year by lowering NO2 levels. Representativity of site selection and the minimal number of samplers for land use regression modelling are considered. Enhancement of community knowledge and attitudes towards collective response were observed and identified as key drivers for successful large-scale monitoring campaigns. The results encourage strengthening collaboration with local communities when exploring environmental health issues.

Integrating health indicators into urban and transport planning: A narrative literature review and participatory process.

Today, urban and transport planners face considerable challenges in designing and retrofitting cities that are prepared for increasing urban populations, and their service and mobility needs. When it comes to health-promoting urban and transport developments, there is also a lack of standardized, quantitative indicators to guide the integration of health components right from the outset, i.e. in the formal planning or zoning phase. We narratively reviewed the literature and organized stakeholder workshops to identify and tailor planning principles and indicators that can be linked to health outcomes. We defined four core planning objectives that previous authoritative studies have suggested to result in positive health outcomes among city dwellers, which are: I) development of compact cities, II) reduction of private motorized transport, III) promotion of active (i.e. walking and cycling) and public transport, IV) development of green and public open space. Built on the review and stakeholder consensus, we identified 10 urban and transport planning principles that work towards achieving the four core objectives thought to provide health benefits for European city dwellers. These 10 planning principles are: 1) land use mix, 2) street connectivity, 3) density, 4) motorized transport reductions, 5) walking, 6) cycling, 7) public transport, 8) multi-modality, 9) green and public open space, and 10) integration of all planning principles. A set of indicators was developed and tailored for each planning principle. The final output of this work is a checklist ready to be applied by urban and transport professionals to integrate health into urban and transport developments in urban environments right from the outset.

Changing the urban design of cities for health: The superblock model.

BACKGROUND: Car-dependent city planning has resulted in high levels of environmental pollution, sedentary lifestyles and increased vulnerability to the effects of climate change. The Barcelona Superblock model is an innovative urban and transport planning strategy that aims to reclaim public space for people, reduce motorized transport, promote sustainable mobility and active lifestyles, provide urban greening and mitigate effects of climate change. We estimated the health impacts of implementing this urban model across Barcelona. METHODS: We carried out a quantitative health impact assessment (HIA) study for Barcelona residents ≥20 years (N = 1,301,827) on the projected Superblock area level (N = 503), following the comparative risk assessment methodology. We 1) estimated expected changes in (a) transport-related physical activity (PA), (b) air pollution (NO2), (c) road traffic noise, (d) green space, and (e) reduction of the urban heat island (UHI) effect through heat reductions; 2) scaled available risk estimates; and 3) calculated attributable health impact fractions. Estimated endpoints were preventable premature mortality, changes in life expectancy and economic impacts. RESULTS: We estimated that 667 premature deaths (95% CI: 235-1,098) could be prevented annually through implementing the 503 Superblocks. The greatest number of preventable deaths could be attributed to reductions in NO2 (291, 95% PI: 0-838), followed by noise (163, 95% CI: 83-246), heat (117, 95% CI: 101-137), and green space development (60, 95% CI: 0-119). Increased PA for an estimated 65,000 persons shifting car/motorcycle trips to public and active transport resulted in 36 preventable deaths (95% CI: 26-50). The Superblocks were estimated to result in an average increase in life expectancy for the Barcelona adult population of almost 200 days (95% CI: 99-297), and result in an annual economic impact of 1.7 billion EUR (95% CI: 0.6-2.8). DISCUSSION: The Barcelona Superblocks were estimated to help reduce harmful environmental exposures (i.e. air pollution, noise, and heat) while simultaneously increase PA levels and access to green space, and thereby provide substantial health benefits. For an equitable distribution of health benefits, the Superblocks should be implemented consistently across the entire city. Similar health benefits are expected for other cities that face similar challenges of environmental pollution, climate change vulnerability and low PA levels, by adopting the Barcelona Superblock model.

Urban health: an example of a "health in all policies" approach in the context of SDGs implementation.

BACKGROUND: Cities are an important driving force to implement the Sustainable Development Goals (SDGs) and the New Urban Agenda. The SDGs provide an operational framework to consider urbanization globally, while providing local mechanisms for action and careful attention to closing the gaps in the distribution of health gains. While health and well-being are explicitly addressed in SDG 3, health is also present as a pre condition of SDG 11, that aims at inclusive, safe, resilient and sustainable cities. Health in All Policies (HiAP) is an approach to public policy across sectors that systematically takes into account the health implications of decisions, seeks synergies, and avoids harmful health impacts in order to improve population health and health equity. HiAP is key for local decision-making processes in the context of urban policies to promote public health interventions aimed at achieving SDG targets. HiAPs relies heavily on the use of scientific evidence and evaluation tools, such as health impact assessments (HIAs). HIAs may include city-level quantitative burden of disease, health economic assessments, and citizen and other stakeholders' involvement to inform the integration of health recommendations in urban policies. The Barcelona Institute for Global Health (ISGlobal)'s Urban Planning, Environment and Health Initiative provides an example of a successful model of translating scientific evidence into policy and practice with regards to sustainable and healthy urban development. The experiences collected through ISGlobal's participation implementing HIAs in several cities worldwide as a way to promote HiAP are the basis for this analysis. AIM: The aim of this article is threefold: to understand the links between social determinants of health, environmental exposures, behaviour, health outcomes and urban policies within the SDGs, following a HiAP rationale; to review and analyze the key elements of a HiAP approach as an accelerator of the SDGs in the context of urban and transport planning; and to describe lessons learnt from practical implementation of HIAs in cities across Europe, Africa and Latin-America. METHODS: We create a comprehensive, urban health related SDGs conceptual framework, by linking already described urban health dimensions to existing SDGs, targets and indicators. We discuss, taking into account the necessary conditions and steps to conduct HiAP, the main barriers and opportunities within the SDGs framework. We conclude by reviewing HIAs in a number of cities worldwide (based on the experiences collected by co-authors of this publication), including city-level quantitative burden of disease and health economic assessments, as practical tools to inform the integration of health recommendations in urban policies. RESULTS: A conceptual framework linking SDGs and urban and transportplanning, environmental exposures, behaviour and health outcomes, following a HiAP rationale, is designed. We found at least 38 SDG targets relevant to urban health, corresponding to 15 SDGs, while 4 important aspects contained in our proposed framework were not present in the SDGs (physical activity, noise, quality of life or social capital). Thus, a more comprehensive HiAP vision within the SDGs could be beneficial. Our analysis confirmed that the SDGs framework provides an opportunity to formulate and implement policies with a HiAP approach. Three important aspects are highlighted: 1) the importance of the intersectoral work and health equity as a cross-cutting issue in sustainable development endeavors; 2) policy coherence, health governance, and stakeholders' participation as key issues; and 3) the need for high quality data. HIAs are a practical tool to implement HiAP. Opportunities and barriers related to the political, legal and health governance context, the capacity to inform policies in other sectors, the involvement of different stakeholders, and the availability of quality data are discussed based on our experience. Quantitative assessments can provide powerful data such as: estimates of annual preventable morbidity and disability-adjusted life-years (DALYs) under compliance with international exposure recommendations for physical activity, exposure to air pollution, noise, heat, and access to green spaces; the associated economic impacts in health care costs per year; and the number of preventable premature deaths when improvements in urban and transport planning are implemented. This information has been used to support the design of policies that promote cycling, walking, public, zero and low-emitting modes of transport, and the provision of urban greening or healthy public open spaces in Barcelona (e.g. Urban Mobility, Green Infrastructure and Biodiversity Plans, or the Superblocks's model), the Bus Rapid Transit and Open Streets initiatives in several Latin American cities or targeted SDGs assessments in Morocco. CONCLUSIONS: By applying tools such as HIA, HiAP can be implemented to inform and improve transport and urban planning to achieve the 2030 SDG Agenda. Such a framework could be potentially used in cities worldwide, including those of less developed regions or countries. Data availability, taking into account equity issues, strenghtening the communication between experts, decision makers and citizens, and the involvement of all major stakeholders are crucial elements for the HiAP approach to translate knowledge into SDG implementation.

Physician notification of their diabetes patients' limited health literacy. A randomized, controlled trial.

BACKGROUND: Many patients with chronic disease have limited health literacy (HL). Because physicians have difficulty identifying these patients, some experts recommend instituting screening programs in clinical settings. It is unclear if notifying physicians of patients' limited HL improves care processes or outcomes. OBJECTIVE: To determine whether notifying physicians of their patients' limited HL affects physician behavior, physician satisfaction, or patient self-efficacy. DESIGN: We screened all patients for limited HL and randomized physicians to be notified if their patients had limited HL skills. PARTICIPANTS: Sixty-three primary care physicians affiliated with a public hospital and 182 diabetic patients with limited HL. MEASUREMENTS: After their visit, physicians reported their management strategies, satisfaction, perceived effectiveness, and attitudes toward HL screening. We also assessed patients' self-efficacy, feelings regarding HL screening's usefulness, and glycemic control. RESULTS: Intervention physicians were more likely than control physicians to use management strategies recommended for patients with limited HL (OR 3.2, P=.04). However, intervention physicians felt less satisfied with their visits (81% vs 93%, P=.01) and marginally less effective (38% vs 53%, P=.10). Intervention and control patients' post-visit self-efficacy scores were similar (12.6 vs 12.9, P=.6). Sixty-four percent of intervention physicians and 96% of patients felt HL screening was useful. CONCLUSIONS: Physicians are responsive to receiving notification of their patients' limited HL, and patients support the potential utility of HL screening. However, instituting screening programs without specific training and/or system-wide support for physicians and patients is unlikely to be a powerful tool in improving diabetes outcomes.

Closing the loop: physician communication with diabetic patients who have low health literacy.

BACKGROUND: Patients recall or comprehend as little as half of what physicians convey during an outpatient encounter. To enhance recall, comprehension, and adherence, it is recommended that physicians elicit patients' comprehension of new concepts and tailor subsequent information, particularly for patients with low functional health literacy. It is not known how frequently physicians apply this interactive educational strategy, or whether it is associated with improved health outcomes. METHODS: We used direct observation to measure the extent to which primary care physicians working in a public hospital assess patient recall and comprehension of new concepts during outpatient encounters, using audiotapes of visits between 38 physicians and 74 English-speaking patients with diabetes mellitus and low functional health literacy. We then examined whether there was an association between physicians' application of this interactive communication strategy and patients' glycemic control using information from clinical and administrative databases. RESULTS: Physicians assessed recall and comprehension of any new concept in 12 (20%) of 61 visits and for 15 (12%) of 124 new concepts. Patients whose physicians assessed recall or comprehension were more likely to have hemoglobin A(1c) levels below the mean (< or = 8.6%) vs patients whose physicians did not (odds ratio, 8.96; 95% confidence interval, 1.1-74.9) (P =.02). After multivariate logistic regression, the 2 variables independently associated with good glycemic control were higher health literacy levels (odds ratio, 3.97; 95% confidence interval, 1.09-14.47) (P =.04) and physicians' application of the interactive communication strategy (odds ratio, 15.15; 95% confidence interval, 2.07-110.78) (P<.01). CONCLUSIONS: Primary care physicians caring for patients with diabetes mellitus and low functional health literacy rarely assessed patient recall or comprehension of new concepts. Overlooking this step in communication reflects a missed opportunity that may have important clinical implications.

Association of health literacy with diabetes outcomes.

CONTEXT: Health literacy is a measure of patients' ability to read, comprehend, and act on medical instructions. Poor health literacy is common among racial and ethnic minorities, elderly persons, and patients with chronic conditions, particularly in public-sector settings. Little is known about the extent to which health literacy affects clinical health outcomes. OBJECTIVES: To examine the association between health literacy and diabetes outcomes among patients with type 2 diabetes. DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional observational study of 408 English- and Spanish-speaking patients who were older than 30 years and had type 2 diabetes identified from the clinical database of 2 primary care clinics of a university-affiliated public hospital in San Francisco, Calif. Participants were enrolled and completed questionnaires between June and December 2000. We assessed patients' health literacy by using the short-form Test of Functional Health Literacy in Adults (s-TOFHLA) in English or Spanish. MAIN OUTCOME MEASURES: Most recent hemoglobin A(1c) (HbA(1c)) level. Patients were classified as having tight glycemic control if their HbA(1c) was in the lowest quartile and poor control if it was in the highest quartile. We also measured the presence of self-reported diabetes complications. RESULTS: After adjusting for patients' sociodemographic characteristics, depressive symptoms, social support, treatment regimen, and years with diabetes, for each 1-point decrement in s-TOFHLA score, the HbA(1c) value increased by 0.02 (P =.02). Patients with inadequate health literacy were less likely than patients with adequate health literacy to achieve tight glycemic control (HbA(1c) < or = 7.2%; adjusted odds ratio [OR], 0.57; 95% confidence interval [CI], 0.32-1.00; P =.05) and were more likely to have poor glycemic control (HbA(1c) > or = 9.5%; adjusted OR, 2.03; 95% CI, 1.11-3.73; P =.02) and to report having retinopathy (adjusted OR, 2.33; 95% CI, 1.19-4.57; P =.01). CONCLUSIONS: Among primary care patients with type 2 diabetes, inadequate health literacy is independently associated with worse glycemic control and higher rates of retinopathy. Inadequate health literacy may contribute to the disproportionate burden of diabetes-related problems among disadvantaged populations. Efforts should focus on developing and evaluating interventions to improve diabetes outcomes among patients with inadequate health literacy.