Physical Activity Over the Lifecourse and Cardiovascular Disease.

Despite improvements in cardiovascular care in recent decades, cardiovascular disease (CVD) remains a leading cause of death worldwide. At its core, CVD is a largely preventable disease with diligent risk factor management and early detection. As highlighted in the American Heart Association's Life's Essential 8, physical activity plays a central role in CVD prevention at an individual and population level. Despite pervasive knowledge of the numerous cardiovascular and noncardiovascular health benefits of physical activity, physical activity has steadily decreased over time and unfavorable changes in physical activity occur throughout people's lives. Here, we use a lifecourse framework to examine the evidence reporting on the association of physical activity with CVD. From in utero to older adults, we review and discuss the evidence detailing how physical activity may prevent incident CVD and mitigate CVD-related morbidity and death across all life stages.

Prospective Association of Daily Steps With Cardiovascular Disease: A Harmonized Meta-Analysis.

BACKGROUND: Taking fewer than the widely promoted "10 000 steps per day" has recently been associated with lower risk of all-cause mortality. The relationship of steps and cardiovascular disease (CVD) risk remains poorly described. A meta-analysis examining the dose-response relationship between steps per day and CVD can help inform clinical and public health guidelines. METHODS: Eight prospective studies (20 152 adults [ie, ≥18 years of age]) were included with device-measured steps and participants followed for CVD events. Studies quantified steps per day and CVD events were defined as fatal and nonfatal coronary heart disease, stroke, and heart failure. Cox proportional hazards regression analyses were completed using study-specific quartiles and hazard ratios (HR) and 95% CI were meta-analyzed with inverse-variance-weighted random effects models. RESULTS: The mean age of participants was 63.2±12.4 years and 52% were women. The mean follow-up was 6.2 years (123 209 person-years), with a total of 1523 CVD events (12.4 per 1000 participant-years) reported. There was a significant difference in the association of steps per day and CVD between older (ie, ≥60 years of age) and younger adults (ie, <60 years of age). For older adults, the HR for quartile 2 was 0.80 (95% CI, 0.69 to 0.93), 0.62 for quartile 3 (95% CI, 0.52 to 0.74), and 0.51 for quartile 4 (95% CI, 0.41 to 0.63) compared with the lowest quartile. For younger adults, the HR for quartile 2 was 0.79 (95% CI, 0.46 to 1.35), 0.90 for quartile 3 (95% CI, 0.64 to 1.25), and 0.95 for quartile 4 (95% CI, 0.61 to 1.48) compared with the lowest quartile. Restricted cubic splines demonstrated a nonlinear association whereby more steps were associated with decreased risk of CVD among older adults. CONCLUSIONS: For older adults, taking more daily steps was associated with a progressively decreased risk of CVD. Monitoring and promoting steps per day is a simple metric for clinician-patient communication and population health to reduce the risk of CVD.

Television Viewing from Young Adulthood to Middle Age and Premature Cardiovascular Disease Events: A Prospective Cohort Study.

BACKGROUND: Previous literature has explored the relationship between television viewing and cardiovascular disease (CVD) in adults; however, there remains a paucity of longitudinal data describing how young adult television viewing relates to premature CVD events. OBJECTIVE: To ascertain the relationship between level and annualized changes in television viewing from young adulthood to middle age and the incidence of premature CVD events before age 60. DESIGN: The Coronary Artery Risk Development in Young Adults (CARDIA) study, a prospective community-based cohort with over 30 years of follow-up (1985-present). PARTICIPANTS: Black and White men and women who were 18-30 years old at baseline (1985-1986). MAIN MEASURES: Independent variables: Individualized television viewing trajectories were developed using linear mixed models. DEPENDENT VARIABLES: Fatal and nonfatal coronary heart disease (CHD), heart failure, and stroke outcomes were analyzed separately and as a combined CVD event outcome. KEY RESULTS: Among 4318 included participants, every 1-h increase in daily hours of television viewing at age 23 was associated with higher odds of incident CHD (adjusted odds ratio [AOR] 1.26, 95% confidence interval [CI] 1.06-1.49) and incident CVD events (AOR 1.16, 95% CI 1.03-1.32). Each additional hour of daily television viewing annually was associated with higher annual odds of CHD incidence (AOR 1.55, 95% CI 1.06-2.25), stroke incidence (AOR 1.58, 95% CI 1.02-2.46), and CVD incidence (AOR 1.32, 95% CI 1.03-1.69). Race and sex modified the association between television viewing level at age 23 and CHD, heart failure, and stroke, with White men most consistently having significant associations. CONCLUSIONS: In this prospective cohort study, greater television viewing in young adulthood and annual increases in television viewing across midlife were associated with incident premature CVD events, particularly CHD. Young adulthood as well as behaviors across midlife may be important periods to promote healthy television viewing behavior patterns.

Dietary patterns and cardiorespiratory fitness in midlife and subsequent all-cause dementia: findings from the cooper center longitudinal study.

BACKGROUND: Identifying lifestyle factors that independently or jointly lower dementia risk is a public health priority given the limited treatment options available to patients. In this cohort study, we examined the associations between Mediterranean or Dietary Approaches to Stop Hypertension (DASH) diet adherence and cardiorespiratory fitness (CRF) with later-life dementia, and assessed whether the associations between dietary pattern and dementia are modified by CRF. METHODS: Data are from 9,095 adults seeking preventive care at the Cooper Clinic (1987-1999) who completed a 3-day dietary record and a maximal exercise test. Alzheimer's disease and related disorders or senile dementia (i.e., all-cause dementia) was identified from Medicare administrative claims (1999-2019). Illness-death models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations between Mediterranean or DASH diet adherence (primary exposure), CRF (secondary exposure), and all-cause dementia, adjusted for demographic and clinical factors. An interaction term was included between diet score and CRF to assess effect modification by CRF. RESULTS: The mean age at baseline was 50.6 (standard deviation [SD]: 8.4) years, and a majority of the study sample were men (77.5%) and White (96.4%). 1449 cases of all-cause dementia were identified over a mean follow-up of 9.2 (SD: 5.8) years. Neither Mediterranean nor DASH diet adherence was associated with dementia risk in fully adjusted models (HR per SD of Mediterranean diet score: 1.00, 95% CI: 0.94, 1.05; HR per SD of DASH diet score: 1.02, 95% CI: 0.96, 1.08). However, participants with higher CRF had a decreased hazard of dementia (HR, per metabolic equivalent of task [MET] increase, Mediterranean model: 0.95, 95% CI: 0.92, 0.98; HR, per MET increase, DASH model: 0.96, 95% CI: 0.92, 0.97). No effect modification by CRF was observed in the association between diet and dementia. CONCLUSIONS: In this sample of apparently healthy middle-aged adults seeking preventive care, higher CRF at midlife was associated with a lower risk of all-cause dementia, though adherence to a Mediterranean or DASH diet was not, and CRF did not modify the diet-dementia association. CRF should be emphasized in multimodal interventions for dementia prevention and investigated among diverse samples.

Association of physical activity and screen time with cardiovascular disease risk in the Adolescent Brain Cognitive Development Study.

BACKGROUND: According to the Physical Activity Guidelines Advisory Committee Scientific Report, limited evidence is available on sedentary behaviors (screen time) and their joint associations with physical activity (steps) for cardiovascular health in adolescence. The objective of this study was to identify joint associations of screen time and physical activity categories with cardiovascular disease (CVD) risk factors (blood pressure, hemoglobin A1c, cholesterol) in adolescence. METHODS: This study analyzed data from the Adolescent Brain Cognitive Development (ABCD) Study, comprising a diverse sample of 4,718 U.S. adolescents aged 10-15 years between 2018 and 2021. Steps were measured by a Fitbit wearable device and levels were categorized as low (1,000-6,000), medium (> 6,000-12,000), and high (> 12,000) averaged daily step counts. Self-reported recreational screen time hours per day were classified as low (0-4), medium (> 4-8), and high (> 8) hours per day. CVD risk factors including blood pressure, hemoglobin A1c, and cholesterol (total and HDL) were measured. RESULTS: The analytical sample averaged 6.6 h of screen time per day and 9,722 steps per day. In models including both screen time and steps, the high screen time category was associated with a 4.27 higher diastolic blood pressure percentile (95% CI 1.83-6.73) and lower HDL cholesterol (B= -2.85, 95% CI -4.77 to -0.94 mg/dL) compared to the low screen time category. Medium (B = 3.68, 95% CI 1.24-6.11) and low (B = 7.64, 95% CI 4.07-11.20) step categories were associated with higher diastolic blood pressure percentile compared to the high step category. The medium step category was associated with lower HDL cholesterol (B= -1.99, 95% CI -3.80 to -0.19 mg/dL) compared to the high step category. Findings were similar when screen time and step counts were analyzed as continuous variables; higher continuous step count was additionally associated with lower total cholesterol (mg/dL). CONCLUSIONS: Combinations of low screen time and high steps were generally associated with favorable cardiovascular health markers including lower diastolic blood pressure and higher HDL cholesterol, which can inform future adolescent health guidelines.

Screen Time from Adolescence to Adulthood and Cardiometabolic Disease: a Prospective Cohort Study.

BACKGROUND: Previous studies have analyzed the relationship between screen time and cardiometabolic disease risk factors among adolescents, but few have examined the longitudinal effects of screen time on cardiometabolic health into adulthood using nationally representative data. OBJECTIVE: To determine prospective associations between screen time and later cardiometabolic disease over a 24-year period using a nationally representative adolescent cohort. DESIGN: Longitudinal prospective cohort data from the National Longitudinal Study of Adolescent to Adult Health (Add Health) collected from 1994 to 2018. PARTICIPANTS: Adolescents aged 11-18 years old at baseline (1994-1995) followed for 24 years. MAIN MEASURES: Predictors: screen time (five repeated measures of self-reported television and video watching from adolescence to adulthood). OUTCOMES: Five repeated measures of body mass index (BMI); two repeated measures of waist circumference, hypertension, hyperlipidemia, and diabetes collected at 15- and 24-year follow-up exams. KEY RESULTS: For the 7105 adolescents in the sample (49.7% female, 35.0% non-white), the baseline adolescent average screen time per day was 2.86 ± 0.08 hours per day, which generally declined through 24-year follow-up. Average BMI at baseline was 22.57 ± 0.13 kg/m2, which increased to 30.27 ± 0.18 kg/m2 through follow-up. By 24-year follow-up, 43.4% of participants had obesity, 8.4% had diabetes, 31.8% had hypertension, and 14.9% had hyperlipidemia. In mixed-effects generalized linear models, each additional hour of screen time per day was associated with 0.06 (95% CI 0.04-0.09) within-person increase in BMI. Each additional hour of screen time per day was associated with higher within-person odds of high waist circumference (AOR 1.17, 95% CI 1.09-1.26), obesity (AOR 1.09, 95% CI 1.03-1.15), and diabetes (AOR 1.17, 95% CI 1.07-1.28). Screen time was not significantly associated with hypertension or hyperlipidemia. CONCLUSIONS: In this prospective cohort study, higher screen time in adolescence was associated with higher odds of select indicators of cardiometabolic disease in adulthood.

Social epidemiology of Fitbit daily steps in early adolescence.

BACKGROUND: Sociodemographic disparities in adolescent physical activity have been documented but mostly rely on self-reported data. Our objective was to examine differences in device-based step metrics, including daily step count (steps d-1), by sociodemographic factors among a diverse sample of 10-to-14-year-old adolescents in the US. METHODS: We analyzed prospective cohort data from Year 2 (2018-2020) of the Adolescent Brain Cognitive Development (ABCD) Study (N = 6460). Mixed-effects models were conducted to estimate associations of sociodemographic factors (sex, sexual orientation, race/ethnicity, household income, parental education, and parental marital status) with repeated measures of steps d-1 over the course of 21 days. RESULTS: Participants (49.6% female, 39.0% racial/ethnic minority) accumulated an average of 9095.8 steps d-1. In mixed-effects models, 1543.6 more steps d-1 were recorded for male versus female sex, Black versus White race (328.8 more steps d-1), heterosexual versus sexual minority sexual orientation (676.4 more steps d-1), >$200,000 versus <$25,000 household income (1003.3 more steps d-1), and having married/partnered parents versus unmarried/unpartnered parents (326.3 more steps d-1). We found effect modification by household income for Black adolescents and by sex for Asian adolescents. CONCLUSIONS: Given sociodemographic differences in adolescent steps d-1, physical activity guidelines should focus on key populations and adopt strategies optimized for adolescents from diverse backgrounds. IMPACT: Sociodemographic disparities in physical activity have been documented but mostly rely on self-reported data, which can be limited by reporting and prevarication bias. In this demographically diverse sample of 10-14-year-old early adolescents in the U.S., we found notable and nuanced sociodemographic disparities in Fitbit steps per day. More daily steps were recorded for male versus female sex, Black versus White race, heterosexual versus sexual minority, >$100,000 versus <$25,000 household income, and having married/partnered versus unmarried/unpartnered parents. We found effect modification by household income for Black adolescents and by sex for Asian adolescents.

Sociodemographic Correlates of Contemporary Screen Time Use among 9- and 10-Year-Old Children.

OBJECTIVE: To determine sociodemographic correlates of contemporary screen time use among a diverse population-based sample of 9- and 10-year-old children. STUDY DESIGN: In 2021, we analyzed cross-sectional baseline (2016-2018) data from the Adolescent Brain Cognitive Development study (n = 10 755). Multiple linear regression analyses were conducted to estimate associations between sociodemographic factors (sex, race/ethnicity, country of birth, household income, parental education) and 6 contemporary forms of screen time (television, videos [eg, YouTube], video games, social networking, texting, and video chat). RESULTS: On average, children reported 3.99 hours of screen time per day across 6 modalities, with the most time spent watching/streaming television shows/movies (1.31 hours), playing video games (1.06 hours), and watching/streaming videos (1.05 hours). On average, Black children reported 1.58 more hours of screen time per day and Asian children reported 0.35 less hours of screen time per day compared with White children (mean 3.46 hours per day), and these trends persisted across most modalities. Boys reported higher overall screen time (0.75 hours more) than girls, which was primarily attributed to video games and videos. Girls reported more time texting, social networking, and video chatting than boys. Higher income was associated with lower screen time usage across all modalities except video chat. However, in high-income households, Latinx children reported 0.65 more hours of screen time per day than White children. CONCLUSIONS: Given the sociodemographic differences in child screen use, guideline implementation strategies can focus on key populations, encourage targeted counseling by pediatricians, and adapt Family Media Use Plans for diverse backgrounds.

Parent-adolescent agreement in reported moderate-to-vigorous intensity physical activity during the COVID-19 pandemic.

PURPOSE: To describe the agreement between parent- and adolescent- reports of adolescent moderate-to-vigorous intensity physical activity (MVPA) and to determine sociodemographic factors associated with MVPA reporting differences during the COVID-19 pandemic. METHODS: We analyzed data collected in May 2020 from the Adolescent Brain Cognitive Development Study (ABCD, N = 4841), a U.S. prospective cohort study. We quantified past weekly adolescent MVPA levels as reported by the parent and adolescent (referent). Intra-class correlation coefficients (ICC) and Bland-Altman plots were used to examine the degree of agreement between parent- and adolescent- reports. RESULTS: When quantifying adolescent MVPA during the same recall period, median (p25, p75) MVPA (h∙wk.- 1) was 2.17 (0.00, 6.00) as reported by adolescents and 1.52 (0.29, 4.75) by parents with a mean difference of 4.89. Statistically significant differences in reports of MVPA were found in households with income > $75,000: on average, adolescents reported higher MVPA levels than their parents. Bland-Altman plots illustrated that, among adolescents reporting no or little MVPA, there was higher parent-adolescent agreement. However, among adolescents reporting high levels of MVPA, there was less agreement between the parent- and adolescent- reports. CONCLUSIONS: Despite more time spent together at home during the pandemic, there was generally low agreement between parent- and adolescent- reports of adolescent MVPA. Future research could examine parent-adolescent agreement of MVPA within the context of device-based measures (e.g., accelerometers), determine reasons for differences in parent-adolescent reporting of MVPA, and inform interventions for improved parental involvement and monitoring of MVPA.

Moderate-to-vigorous intensity physical activity from young adulthood to middle age and metabolic disease: a 30-year population-based cohort study.

OBJECTIVES: To determine the association between moderate-to-vigorous intensity physical activity (MVPA) trajectories (course over age and time) through the adult life course and onset of metabolic disease (diabetes and dyslipidaemia). METHODS: We analysed prospective community-based cohort data of 5115 participants in the Coronary Artery Risk Development in Young Adults study, who were black and white men and women aged 18-30 years at baseline (1985-1986) at four urban sites, collected through 30 years of follow-up. Individualised MVPA trajectories were developed for each participant using linear mixed models. RESULTS: Lower estimated MVPA score at age 18 was associated with a 12% (95% CI 6% to 18%) higher odds of incident diabetes, a 4% (95% CI 1% to 7%) higher odds of incident low high-density lipoprotein (HDL) and a 6% (95% CI 2% to 11%) higher odds of incident high triglycerides. Each additional annual 1-unit reduction in the MVPA score was associated with a 6% (95% CI 4% to 9%) higher annual odds of diabetes incidence and a 4% (95% CI 2% to 6%) higher annual odds of high triglyceride incidence. Analysing various MVPA trajectory groups, participants who were in the most active group at age 18 (over 300 min/week), but with sharp declines in midlife, had higher odds of high low-density lipoprotein and low HDL incidence, compared with those in the most active group at age 18 with subsequent gains. CONCLUSION: Given recent trends in declining MVPA across the life course and associated metabolic disease risk, young adulthood is an important time period for interventions to increase and begin the maintenance of MVPA.

Bidirectional associations of accelerometer-derived physical activity and stationary behavior with self-reported mental and physical health during midlife.

BACKGROUND: Moderate-to-vigorous intensity physical activity (MVPA) is associated with favorable self-rated mental and physical health. Conversely, poor self-rated health in these domains could precede unfavorable shifts in activity. We evaluated bidirectional associations of accelerometer-estimated time spent in stationary behavior (SB), light intensity physical activity (LPA), and MVPA with self-rated health over 10 years in in the CARDIA longitudinal cohort study. METHODS: Participants (n = 894, age: 45.1 ± 3.5; 63% female; 38% black) with valid accelerometry wear and self-rated health at baseline (2005-6) and 10-year follow-up (2015-6) were included. Accelerometry data were harmonized between exams and measured mean total activity and duration (min/day) in SB, LPA, and MVPA; duration (min/day) in long-bout and short-bout SB (≥30 min vs. < 30 min) and MVPA (≥10 min vs. < 10 min) were also quantified. The Short-Form 12 Questionnaire measured both a mental component score (MCS) and physical component score (PCS) of self-rated health (points). Multivariable linear regression associated baseline accelerometry variables with 10-year changes in MCS and PCS. Similar models associated baseline MCS and PCS with 10-year changes in accelerometry measures. RESULTS: Over 10-years, average (SD) MCS increased 1.05 (9.07) points, PCS decreased by 1.54 (7.30) points, and activity shifted toward greater SB and less mean total activity, LPA, and MVPA (all p < 0.001). Only baseline short-bout MVPA was associated with greater 10-year increases in MCS (+ 0.92 points, p = 0.021), while baseline mean total activity, MVPA, and long-bout MVPA were associated with greater 10-year changes in PCS (+ 0.53 to + 1.47 points, all p < 0.005). In the reverse direction, higher baseline MCS and PCS were associated with favorable 10-year changes in mean total activity (+ 9.75 cpm, p = 0.040, and + 15.66 cpm, p < 0.001, respectively) and other accelerometry measures; for example, higher baseline MCS was associated with - 13.57 min/day of long-bout SB (p < 0.001) and higher baseline PCS was associated with + 2.83 min/day of MVPA (p < 0.001) in fully adjusted models. CONCLUSIONS: The presence of bidirectional associations between SB and activity with self-rated health suggests that individuals with low overall activity levels and poor self-rated health are at high risk for further declines and supports intervention programming that aims to dually increase activity levels and improve self-rated health.

Disentangling individual, school, and neighborhood effects on screen time among adolescents and young adults in the United States.

OBJECTIVES: To examine the association between individual, neighborhood, and school-level influences on individual screen time among adolescents and young adults (AYAs) in the National Longitudinal Study of Adolescent to Adult Health. METHODS: We classified screen time continuously as self-reported total hours per week of television, videos, and video/computer games at baseline and categorical as extended screen time (≥14 h per week). We fit cross-classified multilevel models (CCMM) to examine to examine the individual-, school- and neighborhood-level demographic and socioeconomic factors associated with screen time. Models were fit using MLwiN with Bayesian estimation procedures. RESULTS: AYAs reported an average of 22.8 (SD = 19.4) and 21.9 (SD = 20.3) hours of screen time, respectively. At the individual level, younger age, male sex, Black/multiracial race, receipt of public assistance, and lower parental education were associated with higher screen time. At the school level, being out of session (i.e., school and national holidays including summer), having a higher proportion of non-White students, and having a lower proportion of parents with a college education were associated with higher individual screen time. CONCLUSIONS: We found that individual-level factors most influence youth screen time, with smaller contributions from school factors.

Cardiovascular risk and functional burden at midlife: Prospective associations of isotemporal reallocations of accelerometer-measured physical activity and sedentary time in the CARDIA study.

Cardiovascular risk and functional burden, or the accumulation of cardiovascular risk factors coupled with functional decline, may be an important risk state analogy to multimorbidity. We investigated prospective associations of sedentary time (ST), light intensity physical activity (LPA), and moderate to vigorous intensity physical activity (MVPA) with cardiovascular risk and functional burden at midlife. Participants were 1648 adults (mean ± SD age = 45 ± 4 years, 61% female, 39% Black) from Coronary Artery Risk Development in Young Adults (CARDIA) who wore accelerometers in 2005-2006 and 2015-2016. Cardiovascular risk and functional burden was defined as ≥2 cardiovascular risk factors (untreated/uncontrolled hypertension and hypercholesterolemia, type 2 diabetes, reduced kidney function) and/or functional decline conditions (reduced physical functioning and depressive symptoms). Prospective logistic regression models tested single activity, partition, and isotemporal substitution associations of accelerometer-measured ST, LPA, and MVPA with cardiovascular risk and functional burden 10 years later. In isotemporal models of baseline activity, reallocating 24 min of ST to MVPA was associated with 15% lower odds of cardiovascular risk and functional burden (OR: 0.85; CI: 0.75, 0.96). Reallocating 24 min of LPA to MVPA was associated with a 14% lower odds of cardiovascular risk and functional burden (OR: 0.86; CI: 0.75, 0.99). In longitudinal isotemporal models, similar beneficial associations were observed when 10-year increases in MVPA replaced time in ST or LPA. Findings suggest that maintaining an MVPA dose reflecting daily physical activity recommendations in early midlife is associated with lower odds of cardiovascular risk and functional burden later in midlife.

Contemporary screen time modalities among children 9-10 years old and binge-eating disorder at one-year follow-up: A prospective cohort study.

OBJECTIVE: To determine the prospective associations between contemporary screen time modalities in a nationally representative cohort of 9-10-year-old children and binge-eating disorder at one-year follow-up. METHOD: We analyzed prospective cohort data from the Adolescent Brain Cognitive Development (ABCD) Study (N = 11,025). Logistic regression analyses were conducted to estimate associations between baseline child-reported screen time (exposure) and parent-reported binge-eating disorder based on the Kiddie Schedule for Affective Disorders and Schizophrenia (KSADS-5, outcome) at one-year follow-up, adjusting for race/ethnicity, sex, household income, parent education, BMI percentile, site, and baseline binge-eating disorder. RESULTS: Each additional hour of total screen time per day was prospectively associated with 1.11 higher odds of binge-eating disorder at 1-year follow-up (95% CI 1.05-1.18) after adjusting for covariates. In particular, each additional hour of social networking (aOR 1.62, 95% CI 1.18-2.22), texting (aOR 1.40, 95% CI 1.08-1.82), and watching/streaming television shows/movies (aOR 1.39, 95% CI 1.14-1.69) was significantly associated with binge-eating disorder. DISCUSSION: Clinicians should assess screen time usage and binge eating in children and adolescents and advise parents about the potential risks associated with excessive screen time.

Bidirectional 10-year associations of accelerometer-measured sedentary behavior and activity categories with weight among middle-aged adults.

BACKGROUND: Although higher sedentary behavior (SB) with low light intensity (LPA) and moderate-to-vigorous intensity physical activity (MVPA) are thought to increase risk for obesity, other data suggest excess weight may precede these behaviors in the causal pathway. We aimed to investigate 10-year bidirectional associations between SB and activity with weight. METHODS: Analysis included 886 CARDIA participants (aged 38-50 years, 62% female, 38% black) with weight and accelerometry ( ≥ 4 days with ≥ 10 h/day) collected in 2005-6 (ActiGraph 7164) and 2015-6 (ActiGraph wGT3X-BT). Accelerometer data were calibrated, harmonized, and expressed as counts per minute (cpm) and time-dependent intensity categories (min/day of SB, LPA, and MVPA; SB and MVPA were also separated into long-bout and short-bout categories). Linear regression models were constructed to estimate adjusted associations of baseline activity with 10-year change in weight and vice versa. When activity categories were the independent variables, standardized regression coefficients (ßstd.) estimated associations of replacing SB with a one SD increase in other categories, adjusted for accelerometer wear time. RESULTS: Over 10-years, weight increased by a mean 2.55 ± 8.05 kg and mean total activity decreased by 50 ± 153 cpm. In adjusted models, one SD higher baseline mean total activity (ßstd. = -1.4 kg, p < 0.001), LPA (ßstd. = -0.80 kg, p = 0.013), total MVPA (ßstd. = -1.07 kg, p = 0.001), and long-bout MVPA (ßstd. = -1.20 kg, p < 0.001) were associated with attenuated 10-year weight gain. Conversely, a one SD higher baseline weight was associated with unfavorable 10-year changes in daily activity profile including increases in SB (ßstd. = 12.0 min, p < 0.001) and decreases in mean total activity (ßstd. = 14.9 cpm, p = 0.004), LPA (ßstd. = 8.9, p = 0.002), and MVPA (ßstd. = 3.5 min, p = 0.001). Associations varied by race and gender. CONCLUSIONS: Higher SB with lower activity and body weight were bidirectionally related. Interventions that work simultaneously to replace SB with LPA and long-bout MVPA while also using other methods to address excess weight may be optimal.

Body mass index versus bioelectrical impedance analysis for classifying physical function impairment in a racially diverse cohort of midlife women: the Study of Women's Health Across the Nation (SWAN).

BACKGROUND: Body composition strongly influences physical function in older adults. Bioelectrical impedance analysis (BIA) differentiates fat mass from skeletal muscle mass, and may be more useful than body mass index (BMI) for classifying women on their likelihood of physical function impairment. AIMS: This study tested whether BIA-derived estimates of percentage body fat (%BF) and height-normalized skeletal muscle mass (skeletal muscle mass index; SMI) enhance classification of physical function impairment relative to BMI. METHOD: Black, White, Chinese, and Japanese midlife women (N = 1482) in the Study of Women's Health Across the Nation (SWAN) completed performance-based measures of physical function. BMI (kg/m2) was calculated. %BF and SMI were derived through BIA. Receiver-operating characteristic (ROC) curve analysis, conducted in the overall sample and stratified by racial group, evaluated optimal cutpoints of BMI, %BF, and SMI for classifying women on moderate-severe physical function impairment. RESULTS: In the overall sample, a BMI cutpoint of ≥ 30.1 kg/m2 correctly classified 71.1% of women on physical function impairment, and optimal cutpoints for %BF (≥ 43.4%) and SMI (≥ 8.1 kg/m2) correctly classified 69% and 62% of women, respectively. SMI did not meaningfully enhanced classification relative to BMI (change in area under the ROC curve = 0.002; net reclassification improvement = 0.021; integrated discrimination improvement = - 0.003). Optimal cutpoints for BMI, %BF, and SMI varied substantially across race. Among Black women, a %BF cutpoint of 43.9% performed somewhat better than BMI (change in area under the ROC curve = 0.017; sensitivity = 0.69, specificity = 0.64). CONCLUSION: Some race-specific BMI and %BF cutpoints have moderate utility for identifying impaired physical function among midlife women.

Physical activity trajectories and subsequent fall risk: ARIC Study.

To examine the impact of moderate to vigorous intensity physical activity (MVPA) trajectories during midlife and older adulthood with subsequent fall risk in later life. Cross-temporal analyses were conducted in 15,792 participants (27% black, 55% women) aged 45 to 64 years enrolled in the Atherosclerosis Risk in Communities (ARIC) Study. MVPA was collected at Exams 1 (1987-89), 3 (1993-95) and 5 (2011-13) using the ARIC/Baecke questionnaire. Latent class growth analysis was used to identify the MVPA trajectory groups. Reported falls outcomes were collected in 2013-14, 2015-16, and 2016-17. Generalized Linear Models were used to estimate associations of baseline predictors with trajectory class membership, as well as associations of trajectory classes with any falling (adjusted incident relative risks, aIRR) and with number of falls (adjusted relative rates, aRR). Four primary trajectory classes emerged, reflecting longitudinal patterns of maintained high (48%), maintained low (22%), increasing (14%) and decreasing (15%) MVPA. After adjustment for covariates, the decreasing MVPA trajectory group had a 14% higher risk of reporting any falling compared to the maintained high MVPA group [aIRR = 1.14 (1.01, 1.28)]. When compared to the maintained high MVPA group, the maintained low and decreasing group had a 28% [aRR = 1.28 (1.14, 1.44)] and 27% [aRR = 1.27 (1.17, 1.38)] higher rate in the reported number of falls, respectively. Findings support public health campaigns targeting habitual MVPA or exercise for fall prevention and suggest that interventions should be initiated in midlife; a time when individuals may be more able and willing to change behavior.

Perceived and objective characteristics of the neighborhood environment are associated with accelerometer-measured sedentary time and physical activity, the CARDIA Study.

We investigated cross-sectional and longitudinal associations of neighborhood environment characteristics with accelerometer-measured sedentary time (SED), light-intensity physical activity (LPA), and moderate-to-vigorous intensity physical activity (MVPA). Participants were 2120 men and women in the year 20 (2005-2006) and year 30 CARDIA exams (2015-2016). Year 20 neighborhood characteristics included neighborhood cohesion, resources for physical activity, poverty, and racial residential segregation. Physical activity was measured by accelerometer at years 20 and 30. Multivariable linear regression models examined associations of standardized neighborhood measures at year 20 with SED, LPA, and MVPA assessed that year, and with 10-year changes in SED, LPA, and MVPA. Cross-sectionally, a one standard deviation (SD) increase in cohesion was associated with 4.06 less SED min/day (95% CI: -7.98, -0.15), and 4.46 more LPA min/day (95% CI: 0.88, 8.03). Each one SD increase in resources was associated with 1.19 more MVPA min/day (95% CI: 0.06, 2.31). A one SD increase in poverty was associated with 11.18 less SED min/day (95% CI: -21.16, -1.18) and 10.60 more LPA min/day (95% CI: 1.79, 19.41) among black men. No neighborhood characteristic was associated with 10-year changes in physical activity in the full sample; however, a one SD increase in cohesion was associated with a 10-year decrease of 25.44 SED min/day (95% CI: -46.73, -4.14) and an increase of 19.0 LPA min/day (95% CI, 1.89, 36.10) in black men. Characteristics of the neighborhood environment are associated with accelerometer-measured physical activity. Differences were observed by race and sex, with more robust findings observed in black men.

Ten-Year Changes in Accelerometer-Based Physical Activity and Sedentary Time During Midlife: The CARDIA Study.

We describe 10-year changes in accelerometer-determined physical activity (PA) and sedentary time in a midlife cohort of the Coronary Artery Risk Development in Young Adults Study, within and by race and sex groups. Participants (n = 962) wore the accelerometer with valid wear (≥4 of 7 days, ≥10 hours per day) at baseline (2005-2006; ages 38-50 years) and 10-year follow-up (2015-2016; ages 48-60 years). Data were calibrated to account for accelerometer model differences. Participants (mean age = 45.0 (standard deviation, 3.5) years at baseline) had reduced accelerometer counts overall (mean = -65.5 (standard error (SE), 10.2) counts per minute/day), and within race and sex groups (all P < 0.001). Sedentary time increased overall (mean = 37.9 (SE, 3.7) minutes/day) and within race and sex groups, whereas light-intensity PA (mean = -30.6 (SE, 2.7) minutes/day) and moderate- to vigorous-intensity PA (mean = -7.5 (SE, 0.8) minutes/day) declined overall and within race and sex groups (all P < 0.001). Significant differences in 10-year change estimates were noted by race and sex groups for accelerometer counts, sedentary time, and moderate- to vigorous-intensity PA bouts; black men had the greatest reductions in PA compared with other groups. PA declines during midlife were characterized by reductions in light-intensity PA with increases in sedentary time, which may have important health consequences. Targeted efforts are needed to preserve PA, regardless of intensity level, across midlife.

Clinical importance of non-participation in a maximal graded exercise test on risk of non-fatal and fatal cardiovascular events and all-cause mortality: CARDIA study.

While poor performance during a maximal graded exercise test (GXT) predicts cardiovascular events and premature mortality, the potential clinical importance of non-participation in a GXT, either for medical or non-medical reasons, is currently unknown. Data are from 4086 and 3547 Coronary Artery Risk Development in Young Adults (CARDIA) participants who attended the Year 7 (ages 25-37years) and/or 20 exams (ages 38-50years), respectively, which included a GXT. Cox proportional hazard models were used to examine the effect of GXT disposition (at Year 7 and 20, separately) on risk of non-fatal and fatal cardiovascular events and all-cause mortality obtained through 28years of follow-up. A GXT was not conducted or completed according to protocol in 12.9% and 19.1% of participants attending the Year 7 and 20 exams, respectively. After adjustment, participants who missed the Year 20 GXT for medical reasons had a higher risk of cardiovascular events [HR: 4.06 (95% CI: 1.43, 11.5)] and all-cause mortality [HR: 3.07 (95% CI: 1.11, 12.3)] compared to GXT completers; participants who missed at Year 20 for non-medical reasons also had higher risk of all-cause mortality [HR: 2.53 (95% CI: 1.61, 3.99)]. Findings suggest that non-participation in a GXT, regardless of medical or non-medical reason, to be an important predictor of excess risk of adverse health outcomes and premature mortality. Additional patient follow-up, including identification of potential targets for intervention (e.g., weight management and smoking cessation programs), should be conducted at the point of a missed GXT.