Search

The dissertation examines the development of sustainable transportation policy in Mexico City. It argues that while sustainable transportation interventions have been defined as examples of a commitment to democratic planning and redistribution of infrastructure investment, in practice these projects have been implemented in a top-down fashion, legitimized by a handful of experts and have targeted only a handful of central districts. The implementation of these reforms are enabling the re-valorization of central neighborhoods and generating new forms of privatization and spatial inequality. The inequality produced is not only spatial. Sustainable transportation initiatives also produce differentiated publics, reducing participation to a handful of non-state actors, namely, experts and international NGOs.

I develop these claims through the analysis of Metrobus, the city’s BRT system, the bikeshare system Ecobici, and a street parking management program called Ecoparq. I draw on ethnographic evidence collected in Mexico City over 16 months in 2012 and 2013 consisting of extensive in- depth interviews with over 60 city officials, transportation experts, NGO staff members, social movements activists and citizens. I use this data to analyze política de movilidad as a policy space in which multiple actors within and outside the state have come together to redefine the goals, mechanisms and technologies used to plan and implement transportation infrastructure.

I draw on the metaphor of immediacy to analyze the practices that make possible these sustainable transportation projects and bring attention to three important policymaking practices and their effects. First, I argue that the need for an immediate response to environmental crises is generative of new policies that must be implemented quickly by bypassing existing bureaucratic and political structures. Second, I show how first-hand, immediate, experience is as an important temporal- spatial dimension of policymaking. By building pilot projects that appear successful and can make sense to any resident, city officials minimize conflict and bring legitimacy to controversial interventions. And third, I propose that the metaphor of immediacy complicates understandings of the role that infrastructures play in shaping public debates around green futures. Movilidad projects postpone inclusive planning processes in which planners could mediate debates in which citizens, experts and officials co-decide how to make the city more sustainable and democratic.

Cover page: The Politics of Immediacy: Citizenship, Infrastructure and Sustainable Mobility in Mexico City

Article
Peer Reviewed

Cardiovascular damage phenotypes and all-cause and CVD mortality in older adults

UC Davis Previously Published Works (2021)

Purpose

The association between CVD risk factors and mortality is well established, however, current tools for addressing subgroups have focused on the overall burden of disease. The identification of risky combinations of characteristics may lead to a better understanding of physiologic pathways that underlie morbidity and mortality in older adults.

Methods

Participants included 5067 older adults from the Cardiovascular Health Study, followed for up to 6 years. Using latent class analysis (LCA), we created CV damage phenotypes based on probabilities of abnormal brain infarctions, major echocardiogram abnormalities, N-terminal probrain natriuretic peptide, troponin T, interleukin-6, c reactive-protein, galectin-3, cystatin C. We assigned class descriptions based on the probability of having an abnormality among risk factors, such that a healthy phenotype would have low probabilities in all risk factors. Participants were assigned to phenotypes based on the maximum probability of membership. We used Cox-proportional hazards regression to evaluate the association between the categorical CV damage phenotype and all-cause and CVD-mortality.

Results

The analysis yielded 5 CV damage phenotypes consistent with the following descriptions: healthy (59%), cardio-renal (11%), cardiac (15%), multisystem morbidity (6%), and inflammatory (9%). All four phenotypes were statistically associated with a greater risk of all-cause mortality when compared with the healthy phenotype. The multisystem morbidity phenotype had the greatest risk of all-cause death (HR: 4.02; 95% CI: 3.44, 4.70), and CVD-mortality (HR: 4.90, 95% CI: 3.95, 6.06).

Conclusions

Five CV damage phenotypes emerged from CVD risk factor measures. CV damage across multiple systems confers a greater mortality risk compared to damage in any single domain.

Cover page: Cardiovascular damage phenotypes and all-cause and CVD mortality in older adults

Article
Peer Reviewed

Survival following dementia onset: Alzheimer's disease and vascular dementia

UC Berkeley Previously Published Works (2005)

Survival following the onset of dementia has been reported to vary from 3 to over 9 years. We examined mortality in 3602 participants of the Cardiovascular Health (CHS) Cognition Study in four US communities evaluated for dementia incidence between 1992 and 1999 and followed for 6.5 years. By June 2000, 33 of 62 (53.2%) participants who developed vascular dementia (VaD) had died compared to 79 of 245 (32.2%) with Alzheimer's disease (AD), 66 of 151 (43.7%) with both AD and VaD, and 429 of 2318 (18.5%) with normal cognition. Using Cox proportional hazards regression with a time-dependent covariate for dementia status adjusted for age, gender and race, individuals with VaD were more than four times as likely to die during follow-up than those with normal cognition (HR: 4.4, 95% CI: 3.1-6.3). The hazard ratios were 2.1 (95% CI: 1.6-2.7) for AD and 2.5 (95% CI: 1.9-3.3) for both types. Adjusted accelerated life models estimated median survival from dementia onset to death as 3.9 years for those with VaD, 7.1 years for AD, 5.4 years for mixed dementia, and 11.0 years for matched controls with normal cognition. While persons with VaD died primarily from cerebrovascular disease, those with AD/mixed dementia died more frequently from dementia/failure to thrive.

Cover page: Survival following dementia onset: Alzheimer's disease and vascular dementia

Creative Commons 'BY' version 4.0 license

Article
Peer Reviewed

Change in Inflammatory Markers and Cognitive Status in the Oldest‐Old Women from the Study of Osteoporotic Fractures

UC San Francisco Previously Published Works (2014)

Objectives

To determine the association between interleukin-6 (IL-6), IL-6 soluble receptor (sR), and soluble tumor necrosis factor receptor-1 (sTNF-R1) and cognitive status in the oldest-old women.

Design

Twenty-year longitudinal cohort study.

Setting

Four clinical sites in the United States.

Participants

Women from the Study of Osteoporotic Fractures (N = 905; mean age 88.3 ± 2.8 at cognitive status adjudication).

Measurements

At Year 20, cognitive status was adjudicated as normal, mild cognitive impairment (MCI), or dementia. Inflammatory markers were measured from blood serum at Years 10 and 16 in a random sample of women.

Results

Over 10 years, 199 (22.0%) women developed MCI and 145 (16.0%) dementia. There were no significant associations between IL-6 or sTNF-R1 and cognitive status. High IL-6-sR (≥ 37,401.36 pg/mL, highest tertile) at Year 16 was significantly associated with lower risk of dementia (odds ratio (OR) = 0.54, 95% confidence interval (CI) = 0.30-0.97) than in women with lower levels (<37,401.36 pg/mL, lower two tertiles). Women with high IL-6-sR at both time points (OR = 0.39, 95% CI = 0.17-0.89) or who transitioned to a high level (OR = 0.35, 95% CI = 0.14-0.88) had a lower risk of dementia.

Conclusion

In this cohort of white, high-functioning oldest-old women, a consistently high or an increasing level of IL-6-sR was associated with lower risk of dementia. Compared with other studies of younger-old adults, this suggests that the effect of inflammation on dementia may differ in younger-old and the oldest-old individuals. Understanding these differences will be crucial in interpreting results from ongoing clinical trials and in targeting therapeutic strategies to the oldest-old individuals.

Cover page: Change in Inflammatory Markers and Cognitive Status in the Oldest‐Old Women from the Study of Osteoporotic Fractures

Article
Peer Reviewed

Anxiety symptoms and risk of cognitive decline in older community-dwelling men

UC San Francisco Previously Published Works (2017)

Background

Previous research regarding anxiety as a predictor of future cognitive decline in older adults is limited and inconsistent. We examined the independent relationship between anxiety symptoms and subsequent cognitive decline.

Methods

We included 2,818 community-dwelling older men (mean age = 76.1, SD ±5.3 years) who were followed on an average for 3.4 years. We assessed anxiety symptoms at baseline using the Goldberg Anxiety Scale (GAS; range = 0-9). We assessed cognitive function at baseline and at two subsequent visits using the Modified Mini-Mental State Examination (3MS; global cognition) and the Trails B test (executive function).

Results

At baseline, there were 690 (24%) men with mild anxiety symptoms (GAS 1-4) and 226 (8%) men with moderate/severe symptoms (GAS 5-9). Men with anxiety symptoms were more likely to have depressed mood, poor sleep, more chronic medical conditions, and more impairment in activities of daily living compared to those with no anxiety symptoms. Compared to those with no anxiety symptoms at baseline, men with any anxiety symptoms were more likely to have substantial worsening in Trails B completion time (OR = 1.56, 95% CI 1.19, 2.05). The association was attenuated after adjusting for potential confounders, including depression and poor sleep, but remained significant (OR = 1.40, 95% CI 1.04, 1.88).

Conclusion

In cognitively healthy older men, mild anxiety symptoms may potentially predict future decline in executive functioning. Anxiety is likely a manifestation of an underlying neurodegenerative process rather than a cause.

Cover page: Anxiety symptoms and risk of cognitive decline in older community-dwelling men

Article
Peer Reviewed

Racial Differences in Gray Matter Integrity by Diffusion Tensor in Black and White Octogenarians.

UC San Francisco Previously Published Works (2015)

Objective

To quantify racial differences in brain structural characteristics in white and black octogenarians, and to examine whether these characteristics contribute to cognition.

Methods

Cross-sectional study of 283 adults 79-89 years old (59.4% white;42.0% women) with data on gray matter integrity via diffusion tensor imaging (mean diffusivity), gray matter atrophy (GMA), white matter hyperintensities (WMH), literacy, smoking, drinking, income, hypertension and diabetes. Participants were recruited from an ongoing epidemiological study of older adults living in the community with a range of chronic conditions, physical and cognitive function. Standardized betas (sβ) of neuroimaging markers predicting Digit Symbol Substitution Test (DSST) and Modified Mini-Mental State Examination (3MS) scores were computed in multivariable regression models stratified by race.

Results

Compared to whites, blacks had lower DSST (p=0.001) and lower 3MS (p=0.006), but also lower mean diffusivity (i.e. higher gray matter microstructural integrity, p=0.032), independent of gender, income, literacy, body mass index, diabetes and drinking habits. Racial differences were not significant for WMH (p=0.062) or GMA (p=0.4). Among blacks, mean diffusivity and WMH were associated with DSST (sβ=-.209, p=0.037 and -.211, p=.038, respectively) independent of each other and other covariates; among whites, mean diffusivity, but not WMH, was significantly associated with DSST and 3MS (sβ =-.277, p=.002 and -.250, p=0.029, respectively).

Conclusions

In this cohort of octogenarians living in the community, blacks appeared to have higher microstructural integrity of gray matter as compared to whites. This neuroimaging marker was related to higher cognition even in the presence of WMH and other cardiovascular conditions. If confirmed, these findings suggest microstructural gray matter integrity may be a target to improve cognition, especially among blacks who survive to very old age with a range of chronic cardiovascular conditions.

Cover page: Racial Differences in Gray Matter Integrity by Diffusion Tensor in Black and White Octogenarians.

Article
Peer Reviewed

Statins and brain integrity in older adults: Secondary analysis of the Health ABC study

UC San Francisco Previously Published Works (2015)

Introduction

We examined whether statins are associated with better cerebral white (WM) and gray matter (GM) indices in community-dwelling elders.

Methods

In 295 older adults, we compared white matter hyperintensities (WMH) on brain magnetic resonance imaging and, total WM fractional anisotropy (FA) and GM mean diffusivity (MD) on diffusion tensor imaging, of Alzheimer's disease (AD) relevant regions in statin-exposed and statin-unexposed participants stratified by Modified Mini-Mental Status Examination (3MS) score.

Results

There was no overall effect of statin exposure on cerebral structural indices. The interaction between statin exposure and 3MS was significant for total-WMH and WM FA (both P < .05) but not GM MD. In the lowest 3MS tertile (mean: 86), statin-exposed individuals had lower total-WMH and higher WM FA (P = .005 and P = .044) and FA of tracts linked to clinical AD (P-value range= .005-.04) despite statistical adjustments. These differences were not significant in the two higher 3MS tertiles.

Discussion

Statins may benefit WM in older adults vulnerable to dementia.

Cover page: Statins and brain integrity in older adults: Secondary analysis of the Health ABC study