Validation of a Zio XT Patch Accelerometer for the Objective Assessment of Physical Activity in the Atherosclerosis Risk in Communities (ARIC) Study.

BACKGROUND: Combination devices to monitor heart rate/rhythms and physical activity are becoming increasingly popular in research and clinical settings. The Zio XT Patch (iRhythm Technologies, San Francisco, CA, USA) is US Food and Drug Administration (FDA)-approved for monitoring heart rhythms, but the validity of its accelerometer for assessing physical activity is unknown. OBJECTIVE: To validate the accelerometer in the Zio XT Patch for measuring physical activity against the widely-used ActiGraph GT3X. METHODS: The Zio XT and ActiGraph wGT3X-BT (Actigraph, Pensacola, FL, USA) were worn simultaneously in two separately-funded ancillary studies to Visit 6 of the Atherosclerosis Risk in Communities (ARIC) Study (2016-2017). Zio XT was worn on the chest and ActiGraph was worn on the hip. Raw accelerometer data were summarized using mean absolute deviation (MAD) for six different epoch lengths (1-min, 5-min, 10-min, 30-min, 1-h, and 2-h). Participants who had ≥3 days of at least 10 h of valid data between 7 a.m-11 p.m were included. Agreement of epoch-level MAD between the two devices was evaluated using correlation and mean squared error (MSE). RESULTS: Among 257 participants (average age: 78.5 ± 4.7 years; 59.1% female), there were strong correlations between MAD values from Zio XT and ActiGraph (average r: 1-min: 0.66, 5-min: 0.90, 10-min: 0.93, 30-min: 0.93, 1-h: 0.89, 2-h: 0.82), with relatively low error values (Average MSE × 106: 1-min: 349.37 g, 5-min: 86.25 g, 10-min: 56.80 g, 30-min: 45.46 g, 1-h: 52.56 g, 2-h: 54.58 g). CONCLUSIONS: These findings suggest that Zio XT accelerometry is valid for measuring duration, frequency, and intensity of physical activity within time epochs of 5-min to 2-h.

Contemporary screen time modalities and disruptive behavior disorders in children: a prospective cohort study.

BACKGROUND: Cross-sectional studies have demonstrated associations between screen time and disruptive behavior disorders (conduct disorder and oppositional defiant disorder); however, prospective associations remain unknown. This study's objective was to determine the prospective associations of contemporary screen time modalities with conduct and oppositional defiant disorder in a national cohort of 9-11-year-old children. METHODS: We analyzed data from the Adolescent Brain Cognitive Development (ABCD) Study (N = 11,875). Modified Poisson regression analyses were conducted to estimate the associations between baseline child-reported screen time (total and by modality) and parent-reported conduct or oppositional defiant disorder based on the Kiddie Schedule for Affective Disorders and Schizophrenia (KSADS-5) at 1-year follow-up, adjusting for potential confounders. RESULTS: Participants reported an average of 4 hr of total screen time per day at baseline. Each hour of total screen time per day was prospectively associated with a 7% higher prevalence of conduct disorder (95% CI 1.03-1.11) and a 5% higher prevalence of oppositional defiant disorder (95% CI 1.03-1.08) at 1-year follow-up. Each hour of social media per day was associated with a 62% higher prevalence of conduct disorder (95% CI 1.39-1.87). Each hour of video chat (prevalence ratio [PR] 1.21, 95% CI 1.06-1.37), texting (PR 1.19, 95% CI 1.07-1.33), television/movies (PR 1.17, 95% CI 1.10-1.25), and video games (PR 1.14, 95% CI 1.07-1.21) per day was associated with a higher prevalence of the oppositional defiant disorder. When examining thresholds, exposure to >4 hr of total screen time per day was associated with a higher prevalence of conduct disorder (69%) and oppositional defiant disorder (46%). CONCLUSIONS: Higher screen time was prospectively associated with a higher prevalence of new-onset disruptive behavior disorders. The strongest association was between social media and conduct disorder, indicating that future research and interventions may focus on social media platforms to prevent conduct disorder.

Physical activity from young adulthood to middle age and premature cardiovascular disease events: a 30-year population-based cohort study.

BACKGROUND: Although physical activity is generally protective of cardiovascular disease (CVD), less is known about how young adult physical activity relates to premature CVD events. The objective of this study was to determine the association between level and change in physical activity from young adulthood to middle age and incidence of premature CVD events before age 60. METHODS: We analyzed data collected across four urban sites from nine visits over 30 years of follow-up (1985-2016) from the Coronary Artery Risk Development in Young Adults (CARDIA) study, a prospective community-based cohort study of 5115 Black and White women and men aged 18-30 years at baseline (1985-1986). Linear mixed models were used to develop individualized moderate-to-vigorous intensity self-reported physical activity trajectories per participant. Fatal and nonfatal coronary heart disease (CHD), heart failure, and stroke outcomes were analyzed separately and as a combined CVD event outcome. RESULTS: Overall, physical activity declined in young adults as they progressed through middle age. Lower physical activity scores (per 100 exercise units) in 18 year-olds were associated with higher odds of premature CHD (AOR 1.14, 95% CI 1.02-1.28), heart failure (AOR 1.21, 95% CI 1.05-1.38), stroke (AOR 1.20, 95% CI 1.04-1.39), and any CVD (AOR 1.15, 95% CI 1.06-1.24) events. Each additional annual 1-unit reduction in the physical activity score was associated with a higher annual odds of incident heart failure (1.07, 95% CI 1.02-1.13), stroke (1.06, 95% CI 1.00-1.13), and CVD (1.04, 95% CI 1.01-1.07) events. Meeting the minimum (AOR 0.74, 95% CI 0.0.57-0.96) and twice the minimum (AOR 0.55, 95% CI 0.34-0.91) Department of Health and Human Services physical activity guidelines through follow up was protective of premature CVD events. CONCLUSIONS: Given recent trends in declining physical activity with age and associated premature CVD events, the transition from young adult to midlife is an important time period to promote physical activity.

Physical activity trajectories, autonomic balance and cognitive function: The Coronary Artery Risk Development in Young Adults (CARDIA) study.

Physical activity (PA) plays an important role in cognitive health. However, the underlying mechanisms are not fully understood. Cardiac autonomic balance is influenced by PA and implicated in dementia pathogenesis. We examined whether autonomic balance mediates the association between PA and cognitive function. The sample included 1939 participants from the Coronary Artery Risk Development in Young Adults study who completed cognitive testing after 30-year follow-up (baseline: mean age 25.2 ± 3.5y; 58% women; 43% Black). Moderate to vigorous intensity PA (MVPA) was obtained in 7 consecutive examinations over 20 years (Year 0-Year 20). Cardiac autonomic balance was assessed at Year 20 via resting heart rate (RHR), standard deviation normal to normal (SDNN) and root mean square of successive differences (RMSSD). We used group-based trajectory modeling to identify homogenous MVPA trajectory groups, and formal mediation analysis to test whether autonomic function indices mediate the association between MVPA trajectories and cognition. We identified three distinct PA trajectory patterns: (1) Below MVPA guidelines (n = 1122; 57.9%); (2) Meeting MVPA guidelines (n = 652; 33.6%); and (3) Exceeding MVPA guidelines (n = 165; 8.5%). Meeting and exceeding MVPA guidelines were related to better autonomic balance overall, and to improved semantic fluency performance. Statistically, the association between higher MVPA level and verbal ability was mediated by SDNN and RMSSD, but not by RHR. In our sample of young and middle-aged adults, higher MVPA levels over time were associated with better cardiac autonomic function, which explained some of the associations between PA trajectories and better cognition.

The association of motoric cognitive risk with incident dementia and neuroimaging characteristics: The Atherosclerosis Risk in Communities Study.

INTRODUCTION: Motoric cognitive risk (MCR), a clinical syndrome characterized by slow gait speed and subjective cognitive complaints, has been associated with dementia risk. The neuropathological features underlying MCR remain poorly understood. METHODS: The Atherosclerosis Risk in Communities (ARIC) community-based cohort study classified participants using standardized criteria as MCR+/- and mild cognitive impairment (MCI)+/- at study baseline (2011-2013). We examined the 5-year dementia risk and baseline brain structural/molecular abnormalities associated with MCR+ and MCI+ status. RESULTS: Of 5023 nondemented participants included, 204 were MCR+ and 1030 were MCI+. Both MCR+ and MCI+ participants demonstrated increased dementia risk. The pattern of structural brain abnormalities associated with MCR+ differed from that of MCI+. Whereas MCI+ was associated with comparatively smaller volumes in brain regions vulnerable to Alzheimer's disease pathology, MCR+ status was associated with smaller volumes in frontoparietal regions and greater white matter abnormalities. DISCUSSION: MCR may represent a predementia syndrome characterized by prominent white matter abnormalities and frontoparietal atrophy.

Sitting Time, Physical Activity, and Cognitive Impairment in Midlife and Older Adults.

This study cross-sectionally examines the relations of sitting and physical activity (PA) with cognitive impairment in community-dwelling adults aged 55-87 years (n = 3,780). Multivariable logistic regression assessed independent and joint relations of sitting and PA with Montreal Cognitive Assessment scores adjusting for covariates. Sitting ≥75% of the time and not meeting PA guidelines were related to 60% (95% confidence interval [CI] [1.19, 2.17]) and 27% (95% CI [1.06, 1.53]) higher odds for cognitive impairment, respectively. Stratification by age showed that sitting ≥75% of the time was associated with higher cognitive impairment odds in midlife (odds ratio [OR] = 1.86; 95% CI [1.31, 2.65]), but not older adults (OR = 1.06; 95% CI [0.57, 1.95]). Joint association analysis revealed that, overall, the highest odds for cognitive impairment were in those sitting ≥75% of the time while meeting or not meeting PA guidelines (OR = 1.69, 95% CI [1.13, 2.53]; and OR = 1.66, 95% CI [1.19, 2.32], respectively). In conclusion, prolonged sitting and insufficient PA are independent risk markers for cognitive impairment.

National Trends in the Expenditure and Utilization of Chiropractic Care in U.S. Children and Adolescents From the 2007-2016 Medical Expenditure Panel Survey: A Cross Sectional Study.

OBJECTIVES: The purpose of this study was to examine the trends in the expenditure and utilization of chiropractic care in a representative sample of children and adolescents in the United States (US) aged <18 years. METHODS: We evaluated serial cross-sectional data (2007-2016) from the Medical Expenditure Panel Survey. Weighted descriptive statistics were conducted to derive national estimates of expenditure and utilization, and linear regression was used to determine trends over time. Sociodemographic and clinical characteristics of chiropractic users were also reported. RESULTS: A statistically significant increasing trend was observed for the number of children receiving chiropractic care (P <.05) and chiropractic utilization rate (P < .05). Increases in chiropractic expenditure and the number of chiropractic visits were also observed over time but were not statistically significant (P > .05). The mean annual number of visits was 6.4 visits, with a mean expenditure of $71.49 US dollars (USD) per visit and $454.08 USD per child. Children and adolescent chiropractic users in the United States were primarily 14 to 17 years old (39.6%-61.6%), White (71.5%-76.9%), male (50.6%-51.3%), and privately insured (56.7%-60.8%). Chiropractic visits in this population primarily involved low back conditions (52.4%), spinal curvature (14.0%), and head and neck complaints (12.8%). CONCLUSION: The number of children visiting a chiropractor and percent utilization showed a statistically significant, increasing trend from 2007 to 2016; however, total expenditure and the number of chiropractic visits did not significantly differ during this period. These findings provide novel insight into the patterns of chiropractic utilization in this understudied age group.

A semiparametric model for wearable sensor-based physical activity monitoring data with informative device wear.

Wearable sensors provide an exceptional opportunity in collecting real-time behavioral data in free living conditions. However, wearable sensor data from observational studies often suffer from information bias, since participants' willingness to wear the monitoring devices may be associated with the underlying behavior of interest. The aim of this study was to introduce a semiparametric statistical approach for modeling wearable sensor-based physical activity monitoring data with informative device wear. Our simulation study indicated that estimates from the generalized estimating equations showed ignorable bias when device wear patterns were independent of the participants physical activity process, but incrementally more biased when the patterns of device non-wear times were increasingly associated with the physical activity process. The estimates from the proposed semiparametric modeling approach were unbiased both when the device wear patterns were (i) independent or (ii) dependent to the underlying physical activity process. We demonstrate an application of this method using data from the 2003-2004 National Health and Nutrition Examination Survey ($N=4518$), to examine gender differences in physical activity measured using accelerometers. The semiparametric model can be implemented using our R package acc, free software developed for reading, processing, simulating, visualizing, and analyzing accelerometer data, publicly available at the Comprehensive R Archive Network.

Factors associated with civilian and police officer injury during 10 years of officer-involved shooting incidents.

BACKGROUND: Previous officer-involved shooting (OIS) research has focused primarily on antecedents to fatal shootings, with few studies investigating injury more broadly. Our study examined the factors associated with fatal or non-fatal injury to both civilians and officers during OIS incidents, to better understand how harm might be reduced in the most extreme law enforcement scenarios. METHODS: Data included 281 officers involved in 177 unique shooting incidents recorded by Dallas Police Department between 2005 and 2015. Bivariate logistic regression and multivariable generalised estimation equation analyses were used to investigate incident characteristics associated with fatal or non-fatal injury to civilians and officers. RESULTS: Civilian injury occurred in 61% and officer injury in 14% of unique OIS incidents. In adjusted models, multiple shooting officers increased the odds of injury to both civilians (adjusted OR (AOR): 3.22, 95% CI 1.39 to 7.50) and officers (AOR 4.73, 95% CI 1.64 to 13.65). Odds of civilian injury were also significantly higher during the daytime and among non-Hispanic white compared with non-Hispanic black and Hispanic/Latina/o civilians, although a majority of OIS incidents (79%) involved non-Hispanic black or Hispanic/Latino/a civilians. Odds of officer injury were significantly higher for detectives compared with patrol (AOR=9.32, 95% CI 1.85 to 47.03) and during off-duty versus on-duty shootings (AOR=5.23, 95% CI 1.37 to 19.99). CONCLUSIONS: Both civilians and officers are at risk for injury during OIS incidents, though to different degrees and with unique risk factors. Additional research is needed to understand whether these results are replicated elsewhere and to further understand the mechanisms of injury.

Does military veteran status and deployment history impact officer involved shootings? A case-control study.

BACKGROUND: Despite veterans' preference hiring policies by law enforcement agencies, no studies have examined the nature or effects of military service or deployments on health outcomes. This study will examine the effect of military veteran status and deployment history on law enforcement officer (LEO)-involved shootings. METHODS: Ten years of data were extracted from Dallas Police Department records. LEOs who were involved in a shooting in the past 10 years were frequency matched on sex to LEOs never involved in a shooting. Military discharge records were examined to quantify veteran status and deployment(s). Multivariable logistic regression was used to estimate the effect of veteran status and deployment history on officer-involved shooting involvement. RESULTS: Records were abstracted for 516 officers. In the adjusted models, veteran LEOs who were not deployed were significantly more likely to be involved in a shooting than non-veteran officers. Veterans with a deployment history were 2.9 times more likely to be in a shooting than non-veteran officers. CONCLUSIONS: Military veteran status, regardless of deployment history, is associated with increased odds of shootings among LEOs. Future studies should identify mechanisms that explain this relationship, and whether officers who experienced firsthand combat exposure experience greater odds of shooting involvement.

Foot-based audit of streets adjacent to new light rail stations in Houston, Texas: measurement of health-related characteristics of the built environment for physical activity research.

BACKGROUND: Active travel to and from a transit station may provide significant amounts of physical activity and improve health. The ease with which people can traverse the distance to the transit station may impede or support active travel. Therefore, transit stations that have features that are supportive of utilitarian physical activity would be desirable. This study aimed to characterize the built environment surrounding new light rail transit (LRT) stations in the City of Houston, Texas. METHODS: In 2014, we used a series of systematic protocols and a standardized environmental audit instrument, the Analytic Audit Tool, to collect data on segments (streets) that surround 22 LRT stations that were being newly built. Using Geographic Information System (GIS), we assembled all the segments that intersect a 0.25-mile circular buffer around each station for the audit exercise. Several 3- to 4-member teams of trained auditors completed the audit exercise on a subset of these identified segments. Our analysis were descriptive in nature. We provided the frequency distributions of audited features across the study area. We also followed an original algorithm to produce several composite index scores for our study area. The composite index score is indicative of the prevalence of physical activity friendly/unfriendly features in the study area. RESULTS: In all, we audited a total of 590 segments covering a total of 218 US Census blocks, and eight City of Houston super neighborhoods. Findings suggest the environment around the new LRT stations may not be supportive of physical activity. In general, the audited segments lacked land use integration; had abandoned buildings, had uneven sidewalks; were not bike-friendly, had minimal presence of public-recreational facilities that would support physical activity; and had significant physical disorder. Notably, certain attractive and comfort features were frequently to usually available. CONCLUSIONS: Current findings, which will be compared to follow-up audit data, can be useful for future researchers and practitioners interested in the built environment around LRT stations.

Leisure-time physical activity sustained since midlife and preservation of cognitive function: The Atherosclerosis Risk in Communities Study.

INTRODUCTION: We tested the hypotheses that higher levels of and persistence of midlife leisure-time physical activity (LTPA) are associated long-term with lower cognitive decline and less incident dementia. METHODS: A total of 10,705 participants (mean age: 60 years) had LTPA (no, low, middle, or high) measured in 1987-1989 and 1993-1995. LTPA was assessed in relation to incident dementia and 14-year change in general cognitive performance. RESULTS: Over a median follow-up of 17.4 years, 1063 dementia cases were observed. Compared with no LTPA, high LTPA in midlife was associated with lower incidence of dementia (hazard ratio [95% confidence interval], 0.71 [0.61, 0.86]) and lower declines in general cognitive performance (-0.07 standard deviation difference [-0.12 to -0.04]). These associations were stronger when measured against persistence of midlife LTPA over 6 years. DISCUSSION: LTPA is a readily modifiable factor associated inversely with long-term dementia incidence and cognitive decline.

Effect of Media Use on Adolescent Body Weight.

INTRODUCTION: Adolescents spend a substantial amount of time consuming media, including watching television, playing video games, and using electronic devices to access the internet. We examined the relationship between prolonged media use on screen devices and its potential association with obesity through several mechanisms. METHODS: We used data from 659,288 eighth and eleventh grade students who participated in the 2015-2016 School Physical Activity and Nutrition (SPAN) survey in Texas to examine the associations between hours of media use per day and 3 behaviors related to obesity: timing of last food intake, unhealthy eating behavior, and sleep hours. Also, mediation analyses were conducted to examine the pathways between hours of media use and body mass index (BMI). RESULTS: Compared with adolescents who used media 2 hours or less per day, those who used media 6 hours or more had higher odds of nighttime eating (odds ratio [OR], 3.16; 95% confidence interval [CI], 1.76-5.66) and inadequate sleep (OR, 1.57; 95% CI, 1.05-2.36) and a higher coefficient for Unhealthy Eating Index score (3.87; 95% CI, 1.3-6.37). Mediation analysis demonstrated that for males sleep hours and timing of last food intake mediated the pathway between hours of media use and BMI. For females, unhealthy eating behavior mediated this pathway. CONCLUSION: Adolescents who used electronic media 6 or more hours at night had higher odds of unhealthy eating behavior and inadequate sleep hours than those with 2 hours' use or less. Attention to behaviors associated with adolescents' prolonged media use is needed to reduce risk of obesity.

Utilization of Chiropractic Care in US Children and Adolescents: A Cross-Sectional Study of the 2012 National Health Interview Survey.

OBJECTIVE: The purpose of this study was to describe the prevalence of chiropractic utilization and examine sociodemographic characteristics associated with utilization in a representative sample of US children and adolescents aged 4 to 17 years. METHODS: Data are from 9734 respondents to the 2012 National Health Interview Survey. Age, sex, race/ethnicity, geography, family income, parental educational attainment, and other health care providers served as exposure variables. Chiropractic utilization in the past 12 months (yes/no) was the targeted outcome. Weighted crude and adjusted logistic regression models, controlling for relevant covariates, were performed. RESULTS: The 12-month prevalence of chiropractic utilization in US children was 3.0% (95% confidence interval: 2.6%-3.6%). The adjusted odds (95% confidence interval) of chiropractic utilization were higher among 11- to 17-year-olds (2.02 [1.41-2.90]) (vs 4- to10-year-olds), Midwest residents (2.45 [1.36-4.44]) (vs Northeast), families with incomes ≥$100000 (3.25 [1.87-5.66]) (vs <$35000), and those that visited other Complementary and Integrative Health (also known as Complementary and Alternative Medicine) practitioners (11.26 [7.19-17.64]). Blacks and Asians had lower adjusted odds of chiropractic utilization compared with whites (0.17 [0.06-0.47] and 0.17 [0.07-0.43], respectively). Sex, parental education, and having an orthodox medical personal physician were not associated with utilization. CONCLUSION: Although overall prevalence was low, sociodemographic characteristics of child and adolescent users of chiropractic care were identified. Age, race/ethnicity, region of residence, family income, and utilization of other Complementary and Integrative Health services were associated with chiropractic utilization, after adjusting for sociodemographic covariates.

Income, physical activity, sedentary behavior, and the 'weekend warrior' among U.S. adults.

The present study examines the association between income and physical activity intensity along the entire continuum using accelerometry in a nationally representative sample of U.S. adults. Specifically, we assessed the relationship between annual household income, sedentary behavior, light, and moderate-vigorous intensity physical activity, and meeting physical activity guidelines over a brief, 2-day period ('weekend warrior'), and during the entire week. The sample consisted of 5206 National Health and Examination Survey adult participants (2003-2006) who wore accelerometers and completed pertinent survey questions. Ordinary Least Square models were computed to examine the relationship between income and the dependent variables (sedentary behavior, light, and moderate to vigorous intensity activity) adjusting for covariates. Logistic regression was employed to examine the association between income and meeting physical activity guidelines during a 2-day and 7-day time-period. Results indicate that individuals with an annual income of ≥$75,000 engaged in 4.6 more daily minutes of moderate to vigorous activity (p-value<0.01), in comparison to the reference group (<$20,000 annual income). Those in the high-income strata were 1.6 and 1.9 times more likely to meet physical activity guidelines during a 2 and 7-day period (respectively) than their lower income counterparts (p<0.05 for both). Further, those in the high-income strata spent 11.8 more minutes daily being sedentary than their lower income counterparts (p-value<0.01). In conclusion, higher annual household income is related to more intense, less frequent (per week) patterns of physical activity and more daily sedentary time.

U.S. military service and the prevalence of metabolic syndrome: Findings from a cross-sectional analysis of the Cooper Center Longitudinal Study, 1979-2013.

U.S. military service confers both health benefits and risks potentially associated with a clustering of cardiovascular risk factors called metabolic syndrome. However, the association between prior military service and metabolic syndrome has not sufficiently been examined. The purpose of the study was to compare the prevalence of metabolic syndrome by prior military service status. Among 42,370 men (887 with prior military service) examined from 1979 to 2013 at the Cooper Clinic (Dallas, TX), we used a cross-sectional study design to examine the association between military service and metabolic syndrome. First, an unadjusted log binomial regression model was performed by regressing the prevalence of metabolic syndrome on prior service. This was followed by performing Kleinbaum's modeling strategy for assessing confounding. The same methodology was used to explore the association between individual metabolic syndrome risk factors and prior service. Prior military service was not significantly associated with the prevalence of metabolic syndrome (PR=0.98, 0.89-1.07). None of the variables explored were identified as confounders. Participants with prior military service had lower prevalence of both elevated levels of triglycerides (PR=0.89, 0.80-0.99) and low levels of high-density lipoprotein-cholesterol (PR=0.78, 0.70-0.88). They had a higher prevalence of elevated resting systolic blood pressure (PR=1.23, 1.12-1.35). However, none of these associations were significant after adjusting for identified confounders: age; cardiorespiratory fitness; and exam year. Study findings indicate that military service was not independently associated with the prevalence of metabolic syndrome or its components. Future research is warranted longitudinally assessing the impact of military service on long-term outcomes.

Association of cardiorespiratory fitness and adiposity with inflammatory biomarkers in young adults.

OBJECTIVES: Cardiorespiratory fitness (fitness) has been inversely associated with inflammation, but whether the association is attributed to fitness itself or lower levels of adiposity remains uncertain in young adults. The purpose of this study was to determine the association of fitness and adiposity with inflammation in young adults. METHODS: A cross-sectional study was conducted with 88 participants aged 20-34 years. Fitness was assessed by a submaximal treadmill walking test. Adiposity was assessed by body mass index (BMI) and waist circumference (WC). Inflammation was measured by plasma C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) levels using immunoassays. Biological data were log10 transformed. A separate multiple regression analysis was conducted with each inflammatory biomarker as a dependent variable. Covariates (sex, oral contraceptive use, and education level) were adjusted. RESULTS: Fitness was inversely associated with log10 CRP after adjustment for covariates but not after adjusting for BMI or WC. Fitness was inversely associated with log10 IL-6 after adjustment for WC and covariates (ß = -0.341, P = .049) but not after adjusting for BMI. Fitness × WC interaction (partial eta2 = 0.056, P = .033) indicated that high fitness was more strongly associated with low log10 IL-6 in young adults with high WC than those with low WC. CONCLUSIONS: Although adiposity has a stronger association than fitness with CRP and IL-6, higher levels of fitness could be essential for maintaining low levels of IL-6, especially in the presence of high levels of central adiposity.

Ecological Momentary Assessment of Physical Activity: Validation Study.

BACKGROUND: Ecological momentary assessment (EMA) may elicit physical activity (PA) estimates that are less prone to bias than traditional self-report measures while providing context. OBJECTIVES: The objective of this study was to examine the convergent validity of EMA-assessed PA compared with accelerometry. METHODS: The participants self-reported their PA using International Physical Activity Questionnaire (IPAQ) and Behavioral Risk Factor Surveillance System (BRFSS) and wore an accelerometer while completing daily EMAs (delivered through the mobile phone) for 7 days. Weekly summary estimates included sedentary time and moderate-, vigorous-, and moderate-to vigorous-intensity physical activity (MVPA). Spearman coefficients and Lin's concordance correlation coefficients (LCC) examined the linear association and agreement for EMA and the questionnaires as compared with accelerometry. RESULTS: Participants were aged 43.3 (SD 13.1) years, 51.7% (123/238) were African American, 74.8% (178/238) were overweight or obese, and 63.0% (150/238) were low income. The linear associations of EMA and traditional self-reports with accelerometer estimates were statistically significant (P<.05) for sedentary time (EMA: ρ=.16), moderate-intensity PA (EMA: ρ=.29; BRFSS: ρ=.17; IPAQ: ρ=.24), and MVPA (EMA: ρ=.31; BRFSS: ρ=.17; IPAQ: ρ=.20). Only EMA estimates of PA were statistically significant compared with accelerometer for agreement. CONCLUSIONS: The mobile EMA showed better correlation and agreement to accelerometer estimates than traditional self-report methods. These findings suggest that mobile EMA may be a practical alternative to accelerometers to assess PA in free-living settings.

Association Between Sitting Time and Cardiometabolic Risk Factors After Adjustment for Cardiorespiratory Fitness, Cooper Center Longitudinal Study, 2010-2013.

INTRODUCTION: Objective estimates, based on waist-worn accelerometers, indicate that adults spend over half their day (55%) in sedentary behaviors. Our study examined the association between sitting time and cardiometabolic risk factors after adjustment for cardiorespiratory fitness (CRF). METHODS: A cross-sectional analysis was conducted with 4,486 men and 1,845 women who reported daily estimated sitting time, had measures for adiposity, blood lipids, glucose, and blood pressure, and underwent maximal stress testing. We used a modeling strategy using logistic regression analysis to assess CRF as a potential effect modifier and to control for potential confounding effects of CRF. RESULTS: Men who sat almost all of the time (about 100%) were more likely to be obese whether defined by waist girth (OR, 2.61; 95% CI, 1.25-5.47) or percentage of body fat (OR, 3.33; 95% CI, 1.35-8.20) than were men who sat almost none of the time (about 0%). Sitting time was not significantly associated with other cardiometabolic risk factors after adjustment for CRF level. For women, no significant associations between sitting time and cardiometabolic risk factors were observed after adjustment for CRF and other covariates. CONCLUSION: As health professionals struggle to find ways to combat obesity and its health effects, reducing sitting time can be an initial step in a total physical activity plan that includes strategies to reduce sedentary time through increases in physical activity among men. In addition, further research is needed to elucidate the relationships between sitting time and CRF for women as well as the underlying mechanisms involved in these relationships.

Impact of a Mobile Phone Intervention to Reduce Sedentary Behavior in a Community Sample of Adults: A Quasi-Experimental Evaluation.

BACKGROUND: Greater time spent sedentary is linked with increased risk of breast, colorectal, ovarian, endometrial, and prostate cancers. Given steadily increasing rates of mobile phone ownership, mobile phone interventions may have the potential to broadly influence sedentary behavior across settings. OBJECTIVE: The purpose of this study was to examine the short-term impact of a mobile phone intervention that targeted sedentary time in a diverse community sample. METHODS: Adults participated in a quasi-experimental evaluation of a mobile phone intervention designed to reduce sedentary time through prompts to interrupt periods of sitting. Participants carried mobile phones and wore accelerometers for 7 consecutive days. Intervention participants additionally received mobile phone prompts during self-reported sitting and information about the negative health impact of prolonged sedentariness. The study was conducted from December 2012 to November 2013 in Dallas, Texas. Linear mixed model regression analyses were conducted to evaluate the influence of the intervention on daily accelerometer-determined estimates of sedentary and active time. RESULTS: Participants (N=215) were predominantly female (67.9%, 146/215) and nonwhite (black: 50.7%, 109/215; Latino: 12.1%, 26/215; other: 5.6%, 12/215). Analyses revealed that participants who received the mobile phone intervention had significantly fewer daily minutes of sedentary time (B=-22.09, P=.045) and more daily active minutes (B=23.01, P=.04) than control participants. CONCLUSIONS: A simple mobile phone intervention was associated with engaging in less sedentary time and more physical activity. Findings underscore the potential impact of mobile phone interventions to positively influence sedentary behavior and physical activity.