Janne Boone-Heinonen

Active commuting and cardiovascular disease risk: the CARDIA study.

BACKGROUND There is little research on the association of lifestyle exercise, such as active commuting (walking or biking to work), with obesity, fitness, and cardiovascular disease (CVD) risk factors. METHODS This cross-sectional study included 2364 participants enrolled in the Coronary Artery Risk Development in Young Adults (CARDIA) study who worked outside the home during year 20 of the study (2005-2006). Associations between walking or biking to work (self-reported time, distance, and mode of commuting) with body weight (measured height and weight); obesity (body mass index [BMI], calculated as weight in kilograms divided by height in meters squared, >or= 30); fitness (symptom-limited exercise stress testing); objective moderate-vigorous physical activity (accelerometry); CVD risk factors (blood pressure [oscillometric systolic and diastolic]); and serum measures (fasting measures of lipid, glucose, and insulin levels) were separately assessed by sex-stratified multivariable linear (or logistic) regression modeling. RESULTS A total of 16.7% of participants used any means of active commuting to work. Controlling for age, race, income, education, smoking, examination center, and physical activity index excluding walking, men with any active commuting (vs none) had reduced likelihood of obesity (odds ratio [OR], 0.50; 95% confidence interval [CI], 0.33-0.76), reduced CVD risk: ratio of geometric mean triglyceride levels (trig(active))/(trig(nonactive)) = 0.88 (95% CI, 0.80 to 0.98); ratio of geometric mean fasting insulin (FI(active))/(FI(nonactive)) = 0.86 (95% CI, 0.78 to 0.93); difference in mean diastolic blood pressure (millimeters of mercury) (DBP(active)) - (DBP(nonactive)) = -1.67 (95% CI, -3.20 to -0.15); and higher fitness: mean difference in treadmill test duration (in seconds) in men (TT(active)) - (TT(nonactive)) = 50.0 (95% CI, 31.45 to 68.59) and women (TT(active)) - (TT(nonactive)) = 28.77 (95% CI, 11.61 to 45.92). CONCLUSIONS Active commuting was positively associated with fitness in men and women and inversely associated with BMI, obesity, triglyceride levels, blood pressure, and insulin level in men. Active commuting should be investigated as a modality for maintaining or improving health.

Walking: the first steps in cardiovascular disease prevention

Purpose of review Health professionals are presented with the challenge of prescribing physical activity that is likely to be sustained by the sedentary majority. Walking is eminently suited to physical activity prescription for inactive individuals as it is accessible to men and women of all ages and social groups and poses little risk of injury. This paper reviews recent evidence of the health benefits of walking and promotion of walking behavior. Recent findings Large observational studies consistently show associations between walking and cardiovascular disease endpoints over long periods of follow-up. Intervention studies further support the health benefits of walking, showing improvements in clinical biomarkers and measures after shorter periods of follow-up. Walking appears to have cardiovascular disease-related health benefits in younger, middle-aged, and older men and women, in both healthy and patient populations. Pedometer-based, mobile phone-based, and computer-based programs are effective in increasing walking levels. Neighborhood and workplace amenities and programs may be important supports for walking behaviors. Summary Walking has the potential to play a key role in the primary and secondary prevention of cardiovascular disease. Clinicians can prescribe walking to assist patients meet physical activity recommendations and help identify supports available to the patient.

Neighborhood fast food restaurants and fast food consumption: A national study

BackgroundRecent studies suggest that neighborhood fast food restaurant availability is related to greater obesity, yet few studies have investigated whether neighborhood fast food restaurant availability promotes fast food consumption. Our aim was to estimate the effect of neighborhood fast food availability on frequency of fast food consumption in a national sample of young adults, a population at high risk for obesity.MethodsWe used national data from U.S. young adults enrolled in wave III (2001-02; ages 18-28) of the National Longitudinal Study of Adolescent Health (n = 13,150). Urbanicity-stratified multivariate negative binomial regression models were used to examine cross-sectional associations between neighborhood fast food availability and individual-level self-reported fast food consumption frequency, controlling for individual and neighborhood characteristics.ResultsIn adjusted analysis, fast food availability was not associated with weekly frequency of fast food consumption in non-urban or low- or high-density urban areas.ConclusionsPolicies aiming to reduce neighborhood availability as a means to reduce fast food consumption among young adults may be unsuccessful. Consideration of fast food outlets near school or workplace locations, factors specific to more or less urban settings, and the role of individual lifestyle attitudes and preferences are needed in future research.

What neighborhood area captures built environment features related to adolescent physical activity

In research investigating built environment (BE) influences on physical activity (PA), inconsistent neighborhood definitions may contribute to inconsistent findings. Using data from the National Longitudinal Study of Adolescent Health (Wave I; 1994-95), we compared associations between moderate-vigorous PA (MVPA) and PA facility counts and street connectivity measures (intersection density and link:node ratio) within 1, 3, 5, and 8.05 km of each respondents residence (Euclidean neighborhood buffers). BE-MVPA associations varied by BE characteristic, urbanicity, and sex. PA facilities within 3 km buffers and intersection density within 1 km buffers exhibited the most consistent associations with MVPA. Policy recommendations and corresponding research should address potential differences in relevant neighborhood areas across environment feature and population subgroup.

Obesogenic Clusters: Multidimensional Adolescent Obesity-related Behaviors in the U.S.

BackgroundDiet, physical activity, and psychosocial factors are independent and potentially interactive obesity determinants, but few studies have explored complex behavior patterns.PurposeThe purpose of this study is to examine obesity-related behavior patterning and identify high-risk adolescent groups.MethodsCluster analysis identified groups with shared behavior patterns in the National Longitudinal Study of Adolescent Health (1995 and 1996, ages 11–21; N = 9,251). Descriptive and multivariate regression analyses compared sociodemographics and prevalent and incident obesity across clusters.ResultsSeven and six clusters in males and females, respectively, represented behavior patterns such as School Clubs & Sports, Sedentary Behaviors, Dieters, and Junk Food & Low Activity. Sociodemographics varied across clusters. Compared to School Clubs & Sports clusters, adjusted odds of prevalent and incident obesity were higher for most clusters in females but not males.ConclusionsCluster analysis identified several obesogenic behavior patterns, highlighting areas for future research and potential avenues for interventions that target broad lifestyle factors.

Neighborhood socioeconomic status predictors of physical activity through young to middle adulthood: The CARDIA study

Neighborhood socioeconomic status (SES) is related to a wide range of health outcomes, but existing research is dominated by cross-sectional study designs, which are particularly vulnerable to bias by unmeasured characteristics related to both residential location decisions and health-related outcomes. Further, little is known about the mechanisms by which neighborhood SES might influence health. Therefore, we estimated longitudinal relationships between neighborhood SES and physical activity (PA), a theorized mediator of the neighborhood SES-health association. We used data from four years of the Coronary Artery Risk Development in Young Adults (CARDIA) study (n = 5115, 18-30 years at baseline, 1985-1986), a cohort of U.S. young adults followed over 15 years, and a time-varying geographic information system. Using two longitudinal modeling strategies, this is the first study to explicitly examine how the estimated association between neighborhood SES (deprivation) and PA is biased by (a) measured characteristics theorized to influence residential decisions (e.g., controlling for individual SES, marriage, and children in random effects models), and (b) time-invariant, unmeasured characteristics (e.g., controlling for unmeasured motivation to exercise that is constant over time using repeated measures regression modeling, conditioned on the individual). After controlling for sociodemographics (age, sex, race) and individual SES, associations between higher neighborhood deprivation and lower PA were strong and incremental in blacks, but less consistent in whites. Furthermore, adjustment for measured characteristics beyond sociodemographics and individual SES had little influence on the estimated associations; adjustment for unmeasured characteristics attenuated negative associations more strongly in whites than in blacks.

Residential self-selection bias in the estimation of built environment effects on physical activity between adolescence and young adulthood

BackgroundBuilt environment research is dominated by cross-sectional designs, which are particularly vulnerable to residential self-selection bias resulting from health-related attitudes, neighborhood preferences, or other unmeasured characteristics related to both neighborhood choice and health-related outcomes.MethodsWe used cohort data from the National Longitudinal Study of Adolescent Health (United States; Wave I, 1994-95; Wave III, 2001-02; n = 12,701) and a time-varying geographic information system. Longitudinal relationships between moderate to vigorous physical activity (MVPA) bouts and built and socioeconomic environment measures (landcover diversity, pay and public physical activity facilities per 10,000 population, street connectivity, median household income, and crime rate) from adolescence to young adulthood were estimated using random effects models (biased by unmeasured confounders) and fixed effects models (within-person estimator, which adjusts for unmeasured confounders that are stable over time).ResultsRandom effects models yielded null associations except for negative crime-MVPA associations [coefficient (95% CI): -0.056 (-0.083, -0.029) in males, -0.061 (-0.090, -0.033) in females]. After controlling for measured and time invariant unmeasured characteristics using within-person estimators, MVPA was higher with greater physical activity pay facilities in males [coefficient (95% CI): 0.024 (0.006, 0.042)], and lower with higher crime rates in males [coefficient (95% CI): -0.107 (-0.140, -0.075)] and females [coefficient (95% CI): -0.046 (-0.083, -0.009)]. Other associations were null or in the counter-intuitive direction.ConclusionsComparison of within-person estimates to estimates unadjusted for unmeasured characteristics suggest that residential self-selection can bias associations toward the null, as opposed to its typical characterization as a positive confounder. Differential environment-MVPA associations by residential relocation suggest that studies examining changes following residential relocation may be vulnerable to selection bias. The authors discuss complexities of adjusting for residential self-selection and residential relocation, particularly during the adolescent to young adult transition.

Walking for prevention of cardiovascular disease in men and women: a systematic review of observational studies

In this systematic review, walking (a generally accessible activity for a largely sedentary population) was assessed as a preventive risk factor for development of fatal and non‐fatal cardiovascular disease (CVD). PubMed, CINHAL and reference list searches identified 21 peer‐reviewed publications examining walking in relation to CVD; studies assessing active transportation were excluded. Generally, there were dose‐dependent reductions in CVD risk with higher walking duration, distance, energy expenditure and pace. Associations appeared to be stronger for ischaemic stroke than other CVD outcomes such as coronary heart disease or haemorrhagic stroke. Adjustment for clinical CVD risk factors, obesity or other types of physical activity generally attenuated but did not eliminate associations. Because functional status may be an important determinant of walking behaviour in adults, potential bias due to pre‐existing illness is of concern in all studies reviewed, particularly in case–control studies which ascertain walking retrospectively and yielded the strongest associations. Study findings were consistent with current physical activity recommendations, but there is a need for improvements in measurement of walking and other CVD risk factors, more thorough control for pre‐existing illness, examination of mediating or moderating conditions such as obesity and other analytical issues.

Are neighbourhood food resources distributed inequitably by income and race in the USA? Epidemiological findings across the urban spectrum

Objective Many recent policies focus on socioeconomic inequities in availability of healthy food stores and restaurants. Yet understanding of how socioeconomic inequities vary across neighbourhood racial composition and across the range from rural to urban settings is limited, largely due to lack of large, geographically and socio-demographically diverse study populations. Using a national sample, the authors examined differences in neighbourhood food resource availability according to neighbourhood-level poverty and racial/ethnic population in non-urban, low-density urban and high-density urban areas. Design Cross-sectional data from an observational cohort study representative of the US middle and high school-aged population in 1994 followed into young adulthood. Participants Using neighbourhood characteristics of participants in the National Longitudinal Study of Adolescent Health (Wave III, 2001–2002; n=13 995 young adults aged 18–28 years representing 7588 US block groups), the authors examined associations between neighbourhood poverty and race/ethnicity with neighbourhood food resource availability in urbanicity-stratified multivariable linear regression. Primary and secondary outcome measures Neighbourhood availability of grocery/supermarkets, convenience stores and fast-food restaurants (measured as number of outlets per 100 km roadway). Results Neighbourhood race and income disparities were most pronounced in low-density urban areas, where high-poverty/high-minority areas had lower availability of grocery/supermarkets (β coefficient (β)=–1.91, 95% CI –2.73 to –1.09) and convenience stores (β=–2.38, 95% CI –3.62 to –1.14) and greater availability of fast-food restaurants (β=4.87, 95% CI 2.26 to 7.48) than low-poverty/low-minority areas. However, in high-density urban areas, high-poverty/low-minority neighbourhoods had comparatively greater availability of grocery/supermarkets (β=8.05, 95% CI 2.52 to 13.57), convenience stores (β=2.89, 95% CI 0.64 to 5.14) and fast-food restaurants (β=4.03, 95% CI 1.97 to 6.09), relative to low-poverty/low-minority areas. Conclusions In addition to targeting disproportionate fast-food availability in disadvantaged dense urban areas, our findings suggest that policies should also target disparities in grocery/supermarket and fast-food restaurant availability in low-density areas.

Built and socioeconomic environments: patterning and associations with physical activity in U.S. adolescents

BackgroundInter-relationships among built and socioeconomic environmental characteristics may result in confounding of associations between environment exposure measures and health behaviors or outcomes, but traditional multivariate adjustment can be inappropriate due to collinearity.MethodsWe used principal factor analysis to describe inter-relationships between a large set of Geographic Information System-derived built and socioeconomic environment measures for adolescents in the National Longitudinal Study of Adolescent Health (Wave I, 1995-96, n = 17,294). Using resulting factors in sex-stratified multivariate negative binomial regression models, we tested for confounding of associations between built and socioeconomic environment characteristics and moderate to vigorous physical activity (MVPA). Finally, we used knowledge gained from factor analysis to construct replicable environmental measures that account for inter-relationships and avoid collinearity.ResultsUsing factor analysis, we identified three built environment constructs [(1) homogenous landscape; 2) development intensity with high pay facility count; 3) development intensity with high public facility count] and two socioeconomic environment constructs [1) advantageous economic environment, 2) disadvantageous social environment]. In regression analysis, confounding of built environment-MVPA associations by socioeconomic environment factors was stronger than among built environment factors. In fully adjusted models, MVPA was negatively associated with the highest (versus lowest) quartile of homogenous land cover in males [exp(coeff) (95% CI): 0.91 (0.86, 0.96)] and intensity (pay facilities) [exp(coeff) (95% CI): 0.92 (0.85, 0.99)] in females. Single proxy measures (Simpsons diversity index, count of pay facilities, count of public facilities, median household income, and crime rate) representing each environmental construct replicated associations with MVPA.ConclusionsEnvironmental characteristics are inter-related. Both built and SES environments should be incorporated into analysis in order to minimize confounding. Single environmental measures may be useful proxies for environmental constructs in longitudinal analysis and replication in external populations, but more research is needed to better understand mechanisms of action, and ultimately identify policy-relevant environmental determinants of physical activity.