B vitamin intakes modify the association between particulate air pollutants and incidence of all-cause dementia: Findings from the Women's Health Initiative Memory Study.

INTRODUCTION: Particulate air pollutants may induce neurotoxicity by increasing homocysteine levels, which can be lowered by high B vitamin intakes. Therefore, we examined whether intakes of three B vitamins (folate, B12 , and B6 ) modified the association between PM2.5 exposure and incidence of all-cause dementia. METHODS: This study included 7183 women aged 65 to 80 years at baseline. B vitamin intakes from diet and supplements were estimated by food frequency questionnaires at baseline. The 3-year average PM2.5 exposure was estimated using a spatiotemporal model. RESULTS: During a mean follow-up of 9 years, 342 participants developed all-cause dementia. We found that residing in locations with PM2.5 exposure above the regulatory standard (12 µg/m3 ) was associated with a higher risk of dementia only among participants with lower intakes of these B vitamins. DISCUSSION: This is the first study suggesting that the putative neurotoxicity of PM2.5 exposure may be attenuated by high B vitamin intakes.

The Role of Temperature in Modifying the Risk of Ozone-Attributable Mortality under Future Changes in Climate: A Proof-of-Concept Analysis.

Air pollution risk assessments typically estimate ozone-attributable mortality counts using concentration-response (C-R) parameters from epidemiologic studies that treat temperature as a potential confounder. However, some recent epidemiologic studies have indicated that temperature can modify the relationship between short-term ozone exposure and mortality, which has potentially important implications when considering the impacts of climate change on public health. This proof-of-concept analysis quantifies counts of temperature-modified ozone-attributable mortality using temperature-stratified C-R parameters from a multicity study in which the pooled ozone-mortality effect coefficients change in concert with daily temperature. Meteorology downscaled from two global climate models is used with a photochemical transport model to simulate ozone concentrations over the 21st century using two emission inventories: one holding air pollutant emissions constant at 2011 levels and another accounting for reduced emissions through the year 2040. The late century climate models project increased summer season temperatures, which in turn yields larger total counts of ozone-attributable deaths in analyses using temperature-stratified C-R parameters compared to the traditional temperature confounder approach. This analysis reveals substantial heterogeneity in the magnitude and distribution of the temperature-stratified ozone-attributable mortality results, which is a function of regional variability in both the C-R relationship and the model-predicted temperature and ozone.

Dietary and socioeconomic risk factors for fumonisin exposure among women of reproductive age in 18 municipalities in Guatemala from 2013 to 2014.

Fumonisin exposure is common in populations where maize is a dietary staple, such as in Guatemala, and has been associated with negative health outcomes including neural tube defects. The objective of this study was to estimate fumonisin B1 (FB1) exposure among Guatemalan reproductive-age women and develop a better understanding of the dietary and sociodemographic risk factors for exposure. A cross-sectional study in 18 municipalities in Guatemala was conducted. Midwives and study nurses enrolled consenting women and collected individual and household demographic and socioeconomic data. A food frequency questionnaire was administered to estimate quantity and types of food products consumed. A urine sample was collected and urinary fumonisin B1 (uFB1) concentration was measured. A univariable analysis was conducted to identify predictors of low/high uFB1. Multivariable logistic regression was used to calculate adjusted odds ratios (ORs) and 95% confidence intervals (CIs). In total, 775 women had analyzable urine samples. Higher uFB1 levels were associated with speaking Mayan (OR = 2.33, 95% CI:1.44-3.77), less than high school education (OR = 1.61, 95% CI:1.12-2.30), increasing dietary proportion of maize-based foods (OR = 1.02, 95% CI:1.01-1.03), and consumption of tostadas (fried tortillas) (OR = 1.11, 95% CI:1.02-1.22). Lower uFB1 levels were associated with consumption of highly processed maize-based foods (OR = 0.93, 95% CI:0.87-0.99). Tortillas were the most frequently consumed maize-based food among study participants and significantly associated with high uFB1 exposure in the univariable but not multivariable analysis. Consumption of >4,750 grams/week of maize-based foods, >5,184 g/week of locally produced maize-based foods, and >110 servings/week of tortillas were also significantly associated with high uFB1 exposure in univariable analysis. Populations with low socioeconomic status/education levels and high consumption of maize-based foods had higher fumonisin exposure. Interventions aimed at reducing the risk of exposure to mycotoxins through maize in Guatemala, including the increased consumption of non-maize-based foods, should be further explored.

Longitudinal Associations Between Body Mass Index During Young Adulthood, Subsequent Weight Change, and Incident Diabetes During Mid- and Older-Adulthood in Non-Hispanic White and African American Populations: The Atherosclerosis Risk in Communities Study.

Background: Excess body mass index (BMI) and weight gain are well-known risk factors for diabetes. Nevertheless, the associations of BMI and weight gain in young adulthood with subsequent diabetes in African Americans, and the standardized effects of these weight variables have not been well studied. Methods: We studied 12,672 white and African American men and women 45-64 years of age (i.e., during mid-adulthood) who participated in the Atherosclerosis Risk in Communities Study visit 1 (1987-1989), and were reexamined at three follow-up examinations. Associations between recalled BMI at age 25 (i.e., during young adulthood) and subsequent weight change with incident diabetes at ages 45 and above (i.e., during mid-adulthood to older adulthood) were examined using Cox proportional hazard models. Results: Over the 9-year follow-up, we identified 1,501 cases of incident diabetes. The incidence rates were higher among African Americans (men: 24.5 and women: 26.3 per 1,000 person-years) compared to whites (men: 16.3 and women: 10.5 per 1,000 person years). Compared to normal-weight individuals at age 25, those who were overweight or obese and those who gained more weight after age 25 had a higher risk of developing diabetes later in all four race-sex groups with the highest risk in African Americans. In the race-sex groups combined, the mutually adjusted hazard ratio for BMI at age 25 and percent weight change were 1.97 (1.79-2.17) and 2.89 (2.59-3.11), respectively, comparing the 85th to the 15th percentiles of the exposures. Conclusions: African Americans were at higher risk of diabetes than whites. Both higher BMI at age 25 and subsequent weight gain were independently associated with higher risk for diabetes in all the race-sex groups; however, overall weight gain was more potent than BMI.

Air pollution-associated changes in biomarkers of diabetes risk.

BACKGROUND: Ambient particulate matter (PM) and nitrogen oxide (NOx) air pollution may be diabetogenic. OBJECTIVE: To examine longitudinal associations of short- and longer-term mean PM ≤10 µm (PM10), PM ≤2.5 µm (PM2.5), and NOx concentrations with five biomarkers of diabetes risk. METHODS: We studied a stratified, random minority oversample of nondiabetic Women's Health Initiative clinical trials participants with biomarkers and geocoded participant address-specific mean air pollution concentrations available at repeated visits (years = 1993-2004; n = 3,915; mean age = 62.7 years; 84% white). We log-transformed the biomarkers, then used multi-level, mixed-effects, longitudinal models weighted for sampling design/attrition and adjusted for sociodemographic, clinical, and meteorological covariates to estimate their associations with air pollutants. RESULTS: Biomarkers exhibited null to suggestively negative associations with short- and longer-term PM10 and NOx concentrations, e.g., -3.1% (-6.1%, 0.1%), lower homeostatic model assessment of insulin resistance per 10 µg/m3 increase in 12-month PM10. A statistically significant interaction by impaired fasting glucose (IFG) at baseline in this analysis indicated potentially adverse effects only among women with versus without IFG, i.e., 1.4% (-3.5%, 6.5%) versus -4.6% (-7.9%, -1.1%), P interaction < 0.05. In contrast, longer-term PM2.5 concentrations were largely but not statistically significantly associated with higher biomarkers. CONCLUSIONS: Low-level short-term PM10 and NOx concentrations may have negligible adverse effects on biomarkers of diabetes risk. Although longer-term mean PM2.5 concentrations showed primarily null associations with these biomarkers, results suggestively indicated that PM2.5 exposure over the range of concentrations experienced in the United States may adversely affect biomarkers of diabetes risk at the population level, as may longer-term mean PM10 concentrations among women with IFG.

The Association of Long-Term Exposure to Particulate Matter Air Pollution with Brain MRI Findings: The ARIC Study.

BACKGROUND: Increasing evidence links higher particulate matter (PM) air pollution exposure to late-life cognitive impairment. However, few studies have considered associations between direct estimates of long-term past exposures and brain MRI findings indicative of neurodegeneration or cerebrovascular disease. OBJECTIVE: Our objective was to quantify the association between brain MRI findings and PM exposures approximately 5 to 20 y prior to MRI in the Atherosclerosis Risk in Communities (ARIC) study. METHODS: ARIC is based in four U.S. sites: Washington County, Maryland; Minneapolis suburbs, Minnesota; Forsyth County, North Carolina; and Jackson, Mississippi. A subset of ARIC participants underwent 3T brain MRI in 2011-2013 (n=1,753). We estimated mean exposures to PM with an aerodynamic diameter less than 10 or 2.5µm (PM10 and PM2.5) in 1990-1998, 1999-2007, and 1990-2007 at the residential addresses of eligible participants with MRI data. We estimated site-specific associations between PM and brain MRI findings and used random-effect, inverse variance-weighted meta-analysis to combine them. RESULTS: In pooled analyses, higher mean PM2.5 and PM10 exposure in all time periods were associated with smaller deep-gray brain volumes, but not other MRI markers. Higher PM2.5 exposures were consistently associated with smaller total and regional brain volumes in Minnesota, but not elsewhere. CONCLUSIONS: Long-term past PM exposure in was not associated with markers of cerebrovascular disease. Higher long-term past PM exposures were associated with smaller deep-gray volumes overall, and higher PM2.5 exposures were associated with smaller brain volumes in the Minnesota site. Further work is needed to understand the sources of heterogeneity across sites. https://doi.org/10.1289/EHP2152.

Neighborhood characteristics, food deserts, rurality, and type 2 diabetes in youth: Findings from a case-control study.

Little is known about the influence of neighborhood characteristics on risk of type 2 diabetes (T2D) among youth. We used data from the SEARCH for Diabetes in Youth Case-Control Study to evaluate the association of neighborhood characteristics, including food desert status of the census tract, with T2D in youth. We found a larger proportion of T2D cases in tracts with lower population density, larger minority population, and lower levels of education, household income, housing value, and proportion of the population in a managerial position. However, most associations of T2D with neighborhood socioeconomic characteristics were attributable to differences in individual characteristics. Notably, in multivariate logistic regression models, T2D was associated with living in the least densely populated study areas, and this finding requires further exploration.

Parent's Physical Activity Associated With Preschooler Activity in Underserved Populations.

INTRODUCTION: In the U.S., children from low-income families are more likely to be obese. The impact of parent modeling of physical activity (PA) and sedentary behaviors in low-income American ethnic minorities is unclear, and studies examining objective measures of preschooler and parent PA are sparse. METHODS: This cross-sectional study examined 1,003 parent-child pairs who were of low income, largely Latino and African American, and living in one of two geographically disparate metropolitan areas in the U.S. Parents and children wore GT3X/GT3X+ accelerometers for an average of >12 hours/day (7:00am-9:00pm) for 1 week (September 2012 to May 2014). Analysis occurred in 2015-2016. RESULTS: About 75% of children were Latino and >10% were African American. Mean child age was 3.9 years. The majority of children (60%) were normal weight (BMI ≥50th and <85th percentiles), and more than a third were overweight/obese. Children's total PA was 6.03 hours/day, with 1.5 hours spent in moderate to vigorous PA (MVPA). Covariate-adjusted models showed a monotonic, positive association between parent and child minutes of sedentary behavior (ß=0.10, 95% CI=0.06, 0.15) and light PA (ß=0.06; 95% CI=0.03, 0.09). Child and parent MVPA were positively associated up to 40 minutes/day of parent MVPA, but an inverse association was observed when parental MVPA was beyond 40 minutes/day (p=0.002). CONCLUSIONS: Increasing parental PA and reducing sedentary behavior correlate with increased PA-related behaviors in children. However, more work is needed to understand the impact of high levels of parental MVPA on the MVPA levels of their children.

Comparing Two Waist-to-Height Ratio Measurements with Cardiometabolic Risk Factors among Youth with Diabetes.

BACKGROUND: Waist circumference (WC) is commonly measured by either the World Health Organization (WHO) or National Health and Nutrition Examination Survey (NHANES) protocol. OBJECTIVE: Compare the associations of WHO vs. NHANES WC-to-height ratio (WHtR) protocols with cardiometabolic risk factors (CMRFs) in a sample of youth with diabetes. METHODS: For youth (10-19 years old with type 1 [N=3082] or type 2 [N=533] diabetes) in the SEARCH for Diabetes in Youth Study, measurements were obtained of WC (by two protocols), weight, height, fasting lipids (total cholesterol, triglycerides, HDL cholesterol, Non-HDL cholesterol) and blood pressures. Associations of CMRFs with WHO and NHANES WHtR were modeled stratified by body mass index (BMI) percentiles for age/sex: lower BMI (<85th BMI percentile; N=2071) vs. higher BMI (≥85th percentile; N=1594). RESULTS: Among lower-BMI participants, both NHANES and WHO WHtR were associated (p<0.005) with all CMRFs except blood pressure. Among higher-BMI participants, both NHANES and WHO WHtR were associated (p<0.05) with all CMRFs. WHO WHtR was more strongly associated (p<0.05) than NHANES WHtR with triglycerides, non-HDL cholesterol, and systolic blood pressure in lower-BMI participants. Among high-BMI participants, WHO WHtR was more strongly associated (p<0.05) than NHANES WHtR with triglycerides and systolic blood pressure. CONCLUSION: Among youth with diabetes, WHtR calculated from either WC protocol captures cardiometabolic risk. The WHO WC protocol may be preferable to NHANES WC.

Longitudinal associations of nutritional factors with glycated hemoglobin in youth with type 1 diabetes: the SEARCH Nutrition Ancillary Study.

BACKGROUND: Improved glycated hemoglobin (Hb A1c) delays the progression of microvascular and macrovascular complications in individuals with type 1 diabetes (T1D). We previously showed that higher baseline intakes of n-3 (ω-3) fatty acids and leucine are associated with preserved ß cell function 2 y later in youth with T1D. OBJECTIVE: In the current study, we extend this work to explore the longitudinal associations of nutritional factors with Hb A1c in youth with T1D. DESIGN: We included 908 T1D youth with baseline and follow-up Hb A1c measurements. Nutritional factors assessed at baseline were as follows: breastfeeding status and timing of complimentary food introduction; intakes of leucine, carbohydrates, protein, fat, and fiber estimated from a food-frequency questionnaire (FFQ); and plasma biomarkers for vitamins D and E, eicosapentaenoic acid (EPA), and docosahexaenoic acid. We fit linear regression models adjusted for baseline Hb A1c, sociodemographic variables, diabetes-related variables, time between baseline and follow-up visits, saturated fat, physical activity, and for FFQ-derived nutrients, total calories. The vitamin D model was further adjusted for season and body mass index z score. RESULTS: The mean ± SD age and diabetes duration at baseline was 10.8 ± 3.9 y and 10.1 ± 5.8 mo, respectively. A total of 9.3% of participants had poor Hb A1c (value ≥9.5%) at baseline, which increased to 18.3% during follow-up (P < 0.0001). Intakes of EPA (ß = -0.045, P = 0.046), leucine (ß = -0.031, P = 0.0004), and protein (ß = -0.003, P = 0.0002) were significantly negatively associated with follow-up Hb A1c after adjustment for confounders. Intake of carbohydrates was significantly positively (ß = 0.001, P = 0.003) associated with follow-up Hb A1c after adjustment for confounders. CONCLUSIONS: Several nutritional factors may be associated with Hb A1c during early stages of disease progression in youth recently diagnosed with T1D. In addition to the overall role of major macronutrients such as carbohydrates and protein, leucine and n-3 fatty acid intakes, such as of EPA, may be important for long-term glycemic control.

Plasma nutrient biomarkers are associated with waist-to-height ratio in youth with type 1 diabetes.

BACKGROUND: Plasma fatty acids (FAs) and micronutrients have been associated with central obesity in adults; however, previous studies of these associations in adults have yielded mixed results. In addition, no comparable research has been conducted among youth with type 1 diabetes (T1D). OBJECTIVE: We investigated the cross-sectional and longitudinal associations between plasma nutrient biomarkers and waist-to-height ratio (WHtR) in youth with T1D. METHODS: These analyses included 1324 youth aged 3-20 y at T1D diagnosis with a baseline visit in the SEARCH (Search for Diabetes in Youth) Study and a subset of 1178 of these youth with a follow-up visit an average of 23 mo (range: 16-40 mo) after their baseline visit. Plasma phospholipid FAs and vitamins were measured, and estimated desaturase activities were calculated at baseline. Anthropometric measurements and diabetes-related assessments were collected at each visit. Multiple linear regression was used to examine the association between plasma nutrient biomarkers and WHtR. RESULTS: In cross-sectional analysis, plasma palmitic acid (P = 0.004), dihomo-γ-linolenic acid (DGLA; P = 0.017) and Δ6 desaturase (D6D; P = 0.006) were positively correlated with WHtR after adjustment of confounders. Oleic acid (OA; P = 0.002), linoleic acid (LA; P = 0.015), Δ9 desaturase 18 (D9D-18; P = 0.027), and vitamin D (P < 0.0001) were negatively correlated with WHtR after adjustment. Weight status was an effect modifier (P < 0.05). In normal-weight youth, vitamin D (P = 0.003) was negatively associated with WHtR. In obese youth, stearic acid (P = 0.037), DGLA (P < 0.0001), and D6D (P < 0.0001) were positively associated and OA (P = 0.0008), D9D-18 (P = 0.0006), and vitamin D (P < 0.0001) were negatively associated with WHtR. In longitudinal analysis, baseline linoleic acid (P = 0.018), n-6:n-3 (ω-3:ω-6) FA ratio (P = 0.029), vitamin D (P = 0.003), and vitamin E (P < 0.0001) were negatively correlated with WHtR at follow-up only in obese participants. CONCLUSIONS: In T1D youth, plasma FAs and vitamins are associated with WHtR and are modified by weight status. These associations are particularly marked in obese youth.

Dietary patterns associated with HbA1c and LDL cholesterol among individuals with type 1 diabetes in China.

AIMS: To identify dietary patterns that influence cardiometabolic risk among individuals with type 1 diabetes (T1D) in China. METHODS: Data are from a cross-sectional study of T1D in China (n=99). Dietary intake was assessed using three 24-hour recalls. Reduced rank regression was used to identify dietary patterns from a set of 20 food groups that maximized the explained variation in glycated hemoglobin A1c (HbA1c) and low-density lipoprotein (LDL) cholesterol. RESULTS: Dietary pattern 1 was characterized by low intakes of wheat products and high-fat cakes, and high intakes of beans and pickled vegetables. Dietary pattern 2 was characterized by low intakes of high-fat cakes, nuts/seeds, fish/shellfish, and teas/coffee, and high intakes of rice and eggs. Participants in the highest tertile of dietary pattern 1 had significantly (p<0.05) higher HbA1c and LDL cholesterol compared to participants in the lowest tertile: mean difference in HbA1c was 1.0 percentage point (11 mmol/mol) and in LDL cholesterol was 0.36 mmol/L after adjustment for age and household income. Dietary pattern 2 was not associated with HbA1c or LDL cholesterol. CONCLUSIONS: We identified a dietary pattern that is significantly related to HbA1c and LDL cholesterol. These findings provide support for behavioral strategies to prevent complications in individuals with T1D in China.

Spatial-temporal modeling of neighborhood sociodemographic characteristics and food stores.

The literature on food stores, neighborhood poverty, and race/ethnicity is mixed and lacks methods of accounting for complex spatial and temporal clustering of food resources. We used quarterly data on supermarket and convenience store locations from Nielsen TDLinx (Nielsen Holdings N.V., New York, New York) spanning 7 years (2006-2012) and census tract-based neighborhood sociodemographic data from the American Community Survey (2006-2010) to assess associations between neighborhood sociodemographic characteristics and food store distributions in the Metropolitan Statistical Areas (MSAs) of 4 US cities (Birmingham, Alabama; Chicago, Illinois; Minneapolis, Minnesota; and San Francisco, California). We fitted a space-time Poisson regression model that accounted for the complex spatial-temporal correlation structure of store locations by introducing space-time random effects in an intrinsic conditionally autoregressive model within a Bayesian framework. After accounting for census tract-level area, population, their interaction, and spatial and temporal variability, census tract poverty was significantly and positively associated with increasing expected numbers of supermarkets among tracts in all 4 MSAs. A similar positive association was observed for convenience stores in Birmingham, Minneapolis, and San Francisco; in Chicago, a positive association was observed only for predominantly white and predominantly black tracts. Our findings suggest a positive association between greater numbers of food stores and higher neighborhood poverty, with implications for policy approaches related to food store access by neighborhood poverty.

No association of dietary fiber intake with inflammation or arterial stiffness in youth with type 1 diabetes.

AIM: To examine the association of dietary fiber intake with inflammation and arterial stiffness among youth with type 1 diabetes (T1D) in the US. METHODS: Data are from youth ≥ 10 years old with clinically diagnosed T1D for ≥ 3 months and ≥ 1 positive diabetes autoantibody in the SEARCH for Diabetes in Youth Study. Fiber intake was assessed by food frequency questionnaire with measurement error (ME) accounted for by structural sub-models derived using additional 24-h dietary recall data in a calibration sample and the respective exposure-disease model covariates. Markers of inflammation, measured at baseline, included IL-6 (n=1405), CRP (n=1387), and fibrinogen (n=1340); markers of arterial stiffness, measured approximately 19 months post-baseline, were available in a subset of participants and included augmentation index (n=180), pulse wave velocity (n=184), and brachial distensibility (n=177). RESULTS: Mean (SD) T1D duration was 47.9 (43.2) months; 12.5% of participants were obese. Mean (SD) ME-adjusted fiber intake was 15 (2.8) g/day. In multivariable analyses, fiber intake was not associated with inflammation or arterial stiffness. CONCLUSION: Among youth with T1D, fiber intake does not meet recommendations and is not associated with measures of systemic inflammation or vascular stiffness. Further research is needed to evaluate whether fiber is associated with these outcomes in older individuals with T1D or among individuals with higher intakes than those observed in the present study.

Spatial patterning of supermarkets and fast food outlets with respect to neighborhood characteristics.

A large body of literature has reported differences in exposure to environments supporting either healthy (e.g. supermarkets) or unhealthy (e.g. fast food outlets) dietary choices by neighborhood characteristics. We explored the associations of both supermarkets and fast food outlets availability with neighborhood characteristics, and clustering of these two outlet types in a largely rural state. Compared to block groups without a supermarket, those with a supermarket had a significantly higher income, higher housing value, larger population with high school education and above, lower minority population and lower population living below poverty even after controlling for urbanicity and population density of census block groups. Surprisingly, a similar relationship was found for block groups with and without fast food outlets. This was due to spatial co-occurrence and clustering of fast food outlets around supermarket locations. Hence, future studies exploring the associations of food environment with diet or diet-related health outcome should concurrently examine all aspects of food environment (healthy and unhealthy).

Characterizing the food retail environment: impact of count, type, and geospatial error in 2 secondary data sources.

OBJECTIVE: Commercial listings of food retail outlets are increasingly used by community members and food policy councils and in multilevel intervention research to identify areas with limited access to healthier food. This study quantified the amount of count, type, and geospatial error in 2 commercial data sources. METHODS: InfoUSA and Dun and Bradstreet were compared with a validated field census and validity statistics were calculated. RESULTS: Considering only completeness, Dun and Bradstreet data undercounted 24% of existing supermarkets and grocery stores, and InfoUSA, 29%. In addition, considering accuracy of outlet type assignment increased the undercount error to 42% and 39%, respectively. Marked overcount existed as well, and only 43% of existing supermarkets were correctly identified with respect to presence, outlet type, and location. CONCLUSIONS AND IMPLICATIONS: Relying exclusively on secondary data to characterize the food environment will result in substantial error. Whereas extensive data cleaning can offset some error, verification of outlets with a field census is still the method of choice.

Associations of built food environment with body mass index and waist circumference among youth with diabetes.

BACKGROUND: Youth with diabetes are at increased risk for obesity and cardiovascular disease complications. However, less is known about the influence of built food environment on health outcomes in this population. The aim of this study was to explore the associations of accessibility and availability of supermarkets and fast food outlets with Body Mass Index (BMI) z-score and waist circumference among youth with diabetes. METHODS: Information on residential location and adiposity measures (BMI z-score and waist circumference) for 845 youths with diabetes residing in South Carolina was obtained from the South Carolina site of the SEARCH for Diabetes in Youth study. Food outlets data obtained from the South Carolina Department of Health and Environmental Control and InfoUSA were merged based on names and addresses of the outlets. The comprehensive data on franchised supermarket and fast food outlets was then used to construct three accessibility and availability measures around each youth's residence. RESULTS: Increased number and density of chain supermarkets around residence location were associated with lower BMI z-score and waist circumference among youth with diabetes. For instance, for a female child of 10 years of age with height of 54.2 inches and weight of 70.4 pounds, lower supermarket density around residence location was associated with about 2.8-3.2 pounds higher weight, when compared to female child of same age, height and weight with highest supermarket density around residence location. Similarly, lower supermarket density around residence location was associated with a 3.5-3.7 centimeter higher waist circumference, when compared to residence location with the highest supermarket density. The associations of number and density of chain fast food outlets with adiposity measures, however, were not significant. No significant associations were observed between distance to the nearest supermarket and adiposity measures. However, contrary to our expectation, increased distance to the nearest fast food outlet was associated with higher BMI z-score, but not with waist circumference. CONCLUSIONS: Food environments conducive to healthy eating may significantly influence health behaviors and outcomes. Efforts to increase the availability of supermarkets providing options/selections for health-promoting foods may significantly improve the dietary intake and reduce adiposity among youth with diabetes.

Neighborhood context and incidence of type 1 diabetes: the SEARCH for Diabetes in Youth study.

Findings regarding type 1 diabetes mellitus (T1DM) and neighborhood-level characteristics are mixed, with few US studies examining the influence of race/ethnicity. We conducted an ecologic study using SEARCH for Diabetes in Youth Study data to explore the association of neighborhood characteristics and T1DM incidence. 2002-2003 incident cases among youth at four SEARCH centers were included. Residential addresses were geocoded to US Census Tract. Standardized incidence ratios tended to increase with increasing education and median household income. Results from Poisson regression mixed models were similar and stable across race/ethnic groups and population density. Our study suggests a relationship of T1DM incidence with neighborhood-level socioeconomic status, independent of individual-level race/ethnic differences.

Neighborhood level risk factors for type 1 diabetes in youth: the SEARCH case-control study.

BACKGROUND: European ecologic studies suggest higher socioeconomic status is associated with higher incidence of type 1 diabetes. Using data from a case-control study of diabetes among racially/ethnically diverse youth in the United States (U.S.), we aimed to evaluate the independent impact of neighborhood characteristics on type 1 diabetes risk. Data were available for 507 youth with type 1 diabetes and 208 healthy controls aged 10-22 years recruited in South Carolina and Colorado in 2003-2006. Home addresses were used to identify Census tracts of residence. Neighborhood-level variables were obtained from 2000 U.S. Census. Multivariate generalized linear mixed models were applied. RESULTS: Controlling for individual risk factors (age, gender, race/ethnicity, infant feeding, birth weight, maternal age, number of household residents, parental education, income, state), higher neighborhood household income (p = 0.005), proportion of population in managerial jobs (p = 0.02), with at least high school education (p = 0.005), working outside the county (p = 0.04) and vehicle ownership (p = 0.03) were each independently associated with increased odds of type 1 diabetes. Conversely, higher percent minority population (p = 0.0003), income from social security (p = 0.002), proportion of crowded households (0.0497) and poverty (p = 0.008) were associated with a decreased odds. CONCLUSIONS: Our study suggests that neighborhood characteristics related to greater affluence, occupation, and education are associated with higher type 1 diabetes risk. Further research is needed to understand mechanisms underlying the influence of neighborhood context.

Associations of built food environment with dietary intake among youth with diabetes.

OBJECTIVE: To evaluate the associations of supermarket and fast-food outlet accessibility and availability with dietary intake among youth with diabetes. DESIGN: Subjects' residential location and dietary intake was obtained from the SEARCH for Diabetes in Youth study. Food outlet data obtained from the South Carolina Department of Health and Environmental Control and InfoUSA were merged based on names and addresses of the outlets. The comprehensive data were then used to construct accessibility and availability measures for each participant. SETTING: State of South Carolina. PARTICIPANTS: Three hundred fifty-nine youths with diabetes (10 years old and older) from the SEARCH for Diabetes in Youth study. PHENOMENA OF INTEREST: Supermarket and fast-food outlet accessibility and availability; dietary intake represented by Dietary Approaches to Stop Hypertension (DASH) score. ANALYSIS: Generalized estimating equations analyses. RESULTS: Increased availability and accessibility of supermarkets were significantly associated with higher DASH score, even after adjusting for individual-level correlates, urbanicity, and fast-food outlet accessibility or availability. Fast-food accessibility, however, was associated only with specific food groups (meat, sweets, and low-fat dairy intake), not with the DASH score. CONCLUSIONS AND IMPLICATIONS: Efforts to promote environments conducive to healthful eating may significantly improve the overall dietary intake and reduce diet-related health complications among youth with diabetes.