Jonggyu Baek

Persistent ischemic stroke disparities despite declining incidence in Mexican Americans

To determine trends in ischemic stroke incidence among Mexican Americans and non‐Hispanic whites.

'Competitive' food and beverage policies: are they influencing childhood overweight trends?

We examined whether new policies restricting sales in schools of so-called competitive foods and beverages-those that fall outside of what is served through federally reimbursed school meal programs-influenced increasing rates of overweight children in the Los Angeles Unified School District and the rest of California. After these policies, which set stricter nutrition standards for certain food and beverages sold to students, took effect, the rate of increase in overweight children significantly diminished among fifth graders in Los Angeles and among fifth-grade boys and seventh graders in the rest of California. The extent to which the new nutritional policies contributed to the change is unclear. This is one of the first studies examining the postulated population-level influence of recently implemented policies aimed at sales of competitive foods and beverages in schools.

Physical Education Policy Compliance and Children's Physical Fitness

BACKGROUND Physical education policies have received increased attention as a means for improving physical activity levels, enhancing physical fitness, and contributing to childhood obesity prevention. Although compliance at the school and district levels is likely to be critical for the success of physical education policies, few published studies have focused on this issue. PURPOSE This study investigated whether school district-level compliance with California physical education policies was associated with physical fitness among 5th-grade public-school students in California. METHODS Cross-sectional data from FITNESSGRAM(®) 2004-2006, district-level compliance with state physical education requirements for 2004-2006, school- and district-level information, and 2000 U.S. Census data were combined to examine the association between district-level compliance with physical education policies and childrens fitness levels. The analysis was completed in 2010. RESULTS Of the 55 districts with compliance data, 28 (50%) were in compliance with state physical education mandates; these districts represented 21% (216) of schools and 18% (n=16,571) of students in the overall study sample. Controlling for other student-, school-, and district-level characteristics, students in policy-compliant districts were more likely than students in noncompliant districts to meet or exceed physical fitness standards (AOR=1.29, 95% CI=1.03, 1.61). CONCLUSIONS Policy mandates for physical education in schools may contribute to improvements in childrens fitness levels, but their success is likely to depend on mechanisms to ensure compliance.

Neurological, Functional, and Cognitive Stroke Outcomes in Mexican Americans

Background and Purpose— Our objective was to compare neurological, functional, and cognitive stroke outcomes in Mexican Americans (MAs) and non-Hispanic whites using data from a population-based study. Methods— Ischemic strokes (2008–2012) were identified from the Brain Attack Surveillance in Corpus Christi (BASIC) Project. Data were collected from patient or proxy interviews (conducted at baseline and 90 days poststroke) and medical records. Ethnic differences in neurological (National Institutes of Health Stroke Scale: range, 0–44; higher scores worse), functional (activities of daily living/instrumental activities of daily living score: range, 1–4; higher scores worse), and cognitive (Modified Mini-Mental State Examination: range, 0–100; lower scores worse) outcomes were assessed with Tobit or linear regression adjusted for demographics and clinical factors. Results— A total of 513, 510, and 415 subjects had complete data for neurological, functional, and cognitive outcomes and covariates, respectively. Median age was 66 (interquartile range, 57–78); 64% were MAs. In MAs, median National Institutes of Health Stroke Scale, activities of daily living/instrumental activities of daily living, and Modified Mini-Mental State Examination score were 3 (interquartile range, 1–6), 2.5 (interquartile range, 1.6–3.5), and 88 (interquartile range, 76–94), respectively. MAs scored 48% worse (95% CI, 23%–78%) on National Institutes of Health Stroke Scale, 0.36 points worse (95% CI, 0.16–0.57) on activities of daily living/instrumental activities of daily living score, and 3.39 points worse (95% CI, 0.35–6.43) on Modified Mini-Mental State Examination than non-Hispanic whites after multivariable adjustment. Conclusions— MAs scored worse than non-Hispanic whites on all outcomes after adjustment for confounding factors; differences were only partially explained by ethnic differences in survival. These findings in combination with the increased stroke risk in MAs suggest that the public health burden of stroke in this growing population is substantial.

Factors Influencing Sex Differences in Poststroke Functional Outcome

Background and Purpose— Our objective was to identify factors that contribute to or modify the sex difference in poststroke functional outcome. Methods— Ischemic strokes (n=439) were identified from the Brain Attack Surveillance in Corpus Christi (BASIC) Project (2008–2011). Data were ascertained from interviews (baseline and 90 days post stroke) and medical records. Functional outcome was measured as an average of 22 activities of daily living (ADL)/instrumental ADL items (range, 1–4; higher scores worse function). Tobit regression was used to estimate sex differences and to identify confounding and modifying factors. Results— Fifty-one percent were women. Median age was 71 (interquartile range, 59–80) years in women and 64 (interquartile range, 56–77) years in men. Median ADL/instrumental ADL score at 90 days was 2.7 (interquartile range, 1.8–3.6) in women and 2.0 (interquartile range, 1.3–3.1) in men (P<0.01); this difference remained after age-adjustment (P<0.001). Factors contributing to higher ADL/instrumental ADL scores in women included prestroke function, marital status, prestroke cognition, nursing home residence, stroke severity, history of stroke/transient ischemic attack, and body mass index; prestroke function was the largest contributor. Stroke severity modified the sex difference in outcome such that differences were apparent for mild to moderate but not severe strokes. After adjustment, women still had significantly worse functional outcome than men. Conclusions— These findings yield insight into possible strategies and subgroups to target to reduce the sex disparity in stroke outcome; demographics and prestroke and clinical factors explained only 41% of the sex difference in stroke outcome highlighting the need for future research to identify modifiable factors that contribute to sex differences.

Association of Body Mass Index and Mortality After Acute Ischemic Stroke

Background—The prevalence of severe obesity is rising in the United States. Although mild to moderately elevated body mass index (BMI) is associated with reduced mortality after acute ischemic stroke, less is known about severe obesity. Methods and Results—Patients with acute ischemic stroke (n=1791) ≥45 years were identified from the biethnic population–based Brain Attack Surveillance in Corpus Christi (BASIC) study from June 1, 2005, to December 31, 2010. Median follow-up was 660 days. BMI was abstracted from the medical record. Survival was estimated by BMI category (underweight, normal weight, overweight, class 1 obesity, class 2 obesity, and severe obesity) using Kaplan-Meier methods. Hazard ratios for the relationship between BMI modeled continuously and mortality were estimated from Cox regression models after adjustment for patient factors. The median BMI was 27.1 kg/m2 (interquartile range, 23.7–31.2 kg/m2), and 56% were Mexican American. A total of 625 patients (35%) died during the study period. Persons with higher baseline BMI had longer survival in unadjusted analysis (P<0.01). After adjustment for demographics, stroke severity, and stroke and mortality risk factors, the relationship between BMI and mortality was U shaped. The lowest mortality risk was observed among patients with an approximate BMI of 35 kg/m2, whereas those with lower or higher BMI had higher mortality risk. Conclusions—Severe obesity is associated with increased poststroke mortality in middle-aged and older adults. Stroke patients with class 2 obesity had the lowest mortality risk. More research is needed to determine weight management goals among stroke survivors.

Trial of early noninvasive ventilation for ALS: A pilot placebo-controlled study.

Objective: To evaluate the use and tolerability of noninvasive positive pressure ventilation (NIV) in patients with amyotrophic lateral sclerosis (ALS) early in their disease by comparing active NIV and sham NIV in patients not yet eligible for NIV use as recommended by practice guidelines. Methods: This was a single-center, prospective, double-blind, randomized, placebo (sham)–controlled pilot trial. Patients with ALS were randomized to receive either sham NIV or active NIV and underwent active surveillance approximately every 3 months until they reached a forced vital capacity (FVC) <50% or required NIV for clinical symptom management. Results: In total, 54 participants were randomized. The mean NIV use was 2.0 hours (95% confidence interval [CI] 1.1–3.0) per day in the sham NIV treatment group and 3.3 hours (CI 2.0–4.6) per day in the active NIV group, which did not differ by treatment group (p = 0.347). The majority of sham NIV participants (88%) and active NIV participants (73%) reported only mild or no problem with NIV use. Difference of change in FVC through the treatment period by group (0.44 per month) favored active NIV (p = 0.049). Survival and changes in maximal inspiratory or expiratory pressure did not differ between treatment groups. Conclusions: The efficacy of early NIV in ALS should be tested in randomized, placebo-controlled trials. The trial is registered on clinicaltrials.gov (NCT00580593). Classification of evidence: This study provides Class II evidence that for patients with ALS, adherence with NIV and sham NIV are similar.

Distributed Lag Models: Examining Associations Between the Built Environment and Health.

Built environment factors constrain individual level behaviors and choices, and thus are receiving increasing attention to assess their influence on health. Traditional regression methods have been widely used to examine associations between built environment measures and health outcomes, where a fixed, prespecified spatial scale (e.g., 1 mile buffer) is used to construct environment measures. However, the spatial scale for these associations remains largely unknown and misspecifying it introduces bias. We propose the use of distributed lag models (DLMs) to describe the association between built environment features and health as a function of distance from the locations of interest and circumvent a-priori selection of a spatial scale. Based on simulation studies, we demonstrate that traditional regression models produce associations biased away from the null when there is spatial correlation among the built environment features. Inference based on DLMs is robust under a range of scenarios of the built environment. We use this innovative application of DLMs to examine the association between the availability of convenience stores near California public schools, which may affect children’s dietary choices both through direct access to junk food and exposure to advertisement, and children’s body mass index z scores.

Hierarchical Distributed-Lag Models: Exploring Varying Geographic Scale and Magnitude in Associations Between the Built Environment and Health

It is well known that associations between features of the built environment and health depend on the geographic scale used to construct environmental attributes. In the built environment literature, it has long been argued that geographic scales may vary across study locations. However, this hypothesized variation has not been systematically examined due to a lack of available statistical methods. We propose a hierarchical distributed-lag model (HDLM) for estimating the underlying overall shape of food environment-health associations as a function of distance from locations of interest. This method enables indirect assessment of relevant geographic scales and captures area-level heterogeneity in the magnitudes of associations, along with relevant distances within areas. The proposed model was used to systematically examine area-level variation in the association between availability of convenience stores around schools and childrens weights. For this case study, body mass index (weight kg)/height (m)2) z scores (BMIz) for 7th grade children collected via Californias 2001-2009 FitnessGram testing program were linked to a commercial database that contained locations of food outlets statewide. Findings suggested that convenience store availability may influence BMIz only in some places and at varying distances from schools. Future research should examine localized environmental or policy differences that may explain the heterogeneity in convenience store-BMIz associations.

Ethnic Differences in Poststroke Quality of Life in the Brain Attack Surveillance in Corpus Christi (BASIC) Project

Background and Purpose— Mexican Americans (MAs) have an increased risk of stroke and experience worse poststroke disability than non-Hispanic whites, which may translate into worse poststroke quality of life (QOL). We assessed ethnic differences in poststroke QOL, as well as potential modification of associations by age, sex, and initial stroke severity. Methods— Ischemic stroke survivors were identified through the biethnic, population-based Brain Attack Surveillance in Corpus Christi (BASIC) Project. Data were collected from medical records, baseline interviews, and 90-day poststroke interviews. Poststroke QOL was measured at ≈90 days by the validated short-form stroke-specific QOL in 3 domains: overall, physical, and psychosocial (range, 0–5; higher scores represent better QOL). Tobit regression was used to model associations between ethnicity and poststroke QOL scores, adjusted for demographics, clinical characteristics, and prestroke cognition and function. Results— Among 290 eligible stroke survivors (66% MA, 34% non-Hispanic whites, median age=69 years), median scores for overall, physical, and psychosocial poststroke QOL were 3.3, 3.8, and 2.7, respectively. Poststroke QOL was lower for MAs than non-Hispanic whites both overall (mean difference, −0.30; 95% confidence interval, −0.59, −0.01) and in the physical domain (mean difference, −0.47; 95% confidence interval, −0.81, −0.14) after multivariable adjustment. No ethnic difference was found in the psychosocial domain. Age modified the associations between ethnicity and poststroke QOL such that differences were present in older but not in younger ages. Conclusions— Disparities exist in poststroke QOL for MAs and seem to be driven by differences in older stroke patients. Targeted interventions to improve outcomes among MA stroke survivors are urgently needed.