The association between television viewing time and percent body fat in adults varies as a function of physical activity and sex.

BACKGROUND: Data suggest that sedentary behavior is an independent risk factor for obesity; however, the extent to which physical activity (PA) and sex alter this relationship remains unclear. To address this gap, the current study examined the association between television (TV) viewing time and percent body fat (%BF) as a function of PA level and sex. METHODS: Trained interviewers assessed 454 adults at their place of residence. Participants completed questionnaires to determine h of TV watched per week, PA level (inactive = not meeting PA guidelines vs. active = meeting PA guideline), and covariates including demographics (e.g., sex), depression symptoms, perceived stress, fruit and vegetable intake, and environmental support for PA. Foot-to-foot bioelectrical impedance (Tanita TBF-300, Tokyo, Japan) was used to assess %BF. Mixed models were generated to examine the association between TV h/wk. and %BF as a function of PA level and sex while accounting for the multi-level nature of the data (neighborhood- and individual-levels) and covariates. RESULTS: Participants were 44.4 ± 14.0 (Mean + Standard Deviation) years of age with 33.2 ± 11.1%BF, and watched 19.3 ± 15.5 h/wk. of TV. Most were female (70.9%) and inactive (63.2%). Mixed model regression demonstrated that among inactive participants, each additional h of TV viewed/wk. was associated with a 1.03% increase in %BF; TV h/wk. and %BF were not associated in active adults. When models were further stratified by sex, h of TV viewed/wk. were significantly associated with %BF only in inactive females. Each additional h of TV viewed/wk. was associated with an increase in %BF of 1.14%. CONCLUSION: Interventions targeting PA and/or TV viewing time may be a high-priority to curb excess BF accumulation especially among inactive females.

Towards a demographic risk profile for sedentary behaviours in middle-aged British adults: a cross-sectional population study.

OBJECTIVES: In response to a call from the American Heart Association to more clearly identify the demographic factors associated with sedentary behaviours, this study aimed to identify the hierarchy of demographic characteristics associated with the sedentary behaviours of television viewing, recreational computer use and driving. DESIGN: Cross-sectional analysis of baseline data collected as part of the UK Biobank. The UK Biobank is a population cohort recruited from 22 centres across the UK. Participants aged between 37 and 73 years were recruited between 2006 and 2010. METHODS: Decision tree models were generated for the sedentary behaviour outcomes of hours/day spent television viewing, recreational computer use and all driving; a sum of time spent in these sedentary behaviours ('overall') was computed. Age, sex, race, college attendance, employment, shift-work, urban versus rural residence as well as physical activity were considered as predictors. RESULTS: The analytic sample comprised 415 666 adults who were mostly female (54.2%), white (95.2%), non-college attendee (64.5%), employed (61.7%), lived in an urban centre (85.5%), with a mean age of 56.6 (SD=8.1) years. Television viewing was most common sedentary behaviour (2.7 hour/day vs 1.1 for recreational computer use and 1.0 for all driving). Males (tier 1), who did not attend college (tier 2) were the highest risk group for overall sedentary time. Adults with no college attendance (tier 1) and were retired (tier 2) were the most high-risk demographic group for television viewing. College attendees (tier 1) were highest risk for recreational computer use. Adults who were employed (tier 1), male (tier 2) and did not attend college (tier 3) were most at risk for driving CONCLUSIONS: Daily time spent in different sedentary behaviours varies by sex, employment status and college attendance status. The development of targeted interventions to reduce sedentary behaviour in different demographic subgroups is needed.

Interactive effects of sleep duration and morning/evening preference on cardiovascular risk factors.

Background: Sleep duration and morningness/eveningness (circadian preference) have separately been associated with cardiovascular risk factors (i.e. tobacco use, physical inactivity). Interactive effects are plausible, resulting from combinations of sleep homeostatic and circadian influences. These have not been examined in a population sample. Methods: Multivariable regression models were used to test the associations between combinations of sleep duration (short [≤6 h], adequate [7-8 h], long [≥9 h]) and morning/evening preference (morning, somewhat morning, somewhat evening, evening) with the cardiovascular risk factors of tobacco use, physical inactivity, high sedentary behaviour, obesity/overweight and eating fewer than 5 daily servings of fruit and vegetables, in a cross-sectional sample of 439 933 adults enrolled in the United Kingdom Biobank project. Results: Participants were 56% female, 95% white and mean age was 56.5 (SD = 8.1) years. Compared with adequate sleep with morning preference (referent group), long sleep with evening preference had a relative odds of 3.23 for tobacco use, a 2.02-fold relative odds of not meeting physical activity recommendations, a 2.19-fold relative odds of high screen-based sedentary behaviour, a 1.47-fold relative odds of being obese/overweight and a 1.62-fold relative odds of <5 fruit and vegetable daily servings. Adequate sleep with either morning or somewhat morning preference was associated with a lower prevalence and odds for all cardiovascular risk behaviours except fruit and vegetable intake. Conclusions: Long sleepers with evening preference may be a sleep phenotype at high cardiovascular risk. Further work is needed to examine these relationships longitudinally and to assess the effects of chronotherapeutic interventions on cardiovascular risk behaviours.

Perceived neighborhood safety related to physical activity but not recreational screen-based sedentary behavior in adolescents.

BACKGROUND: A growing proportion of adolescents have poor cardiovascular health behaviors, including low levels of physical activity and high levels of sedentary behavior, thus increasing the likelihood of poor heart health in later years. This study tested the hypothesis that low perceived neighborhood safety would be associated with low levels of physical activity and high levels of recreational sedentary behavior in high-school students. METHODS: Using cross-sectional, weighted data from the 2015 Pennsylvania (USA) State and Philadelphia city Youth Risk Behavior Survey, multivariable logistic regression modeling was used to examine the association between perceived neighborhood safety, and physical activity levels and recreational screen-based sedentary behavior time respectively, while controlling for potential confounders. RESULTS: After adjustment for other significant correlates of physical activity, students with low perceived neighborhood safety had a 21% reduced odds of being physically active on 5 or more days of the last week as compared to those who felt safe (p = 0.044). Perceived safety was not related to sedentary behavior; but sports team participation emerged as a strong correlate of low screen-based sedentary behavior (OR = 0.73, p = .002). CONCLUSION: These data add to a growing body of work demonstrating the importance of perceived safety with physical activity levels in youth. Sports team participation may be a viable target to reduce screen-based sedentary time.

Characterizing Cardiovascular Health and Evaluating a Low-Intensity Intervention to Promote Smoking Cessation in a Food-Assistance Population.

Food assistance recipients are at higher risk for poor cardiovascular health given their propensity to poor dietary intake and tobacco use. This study sought to evaluate the cardiovascular health status, and determine the impact of a low-intensity smoking cessation education intervention that connected mobile food pantry participants to state quit-smoking resources. A pre-post design with a 6-week follow-up was used to evaluate the impact of a 10-12 min smoking cessation education session implemented in five food pantries in Delaware. Baseline cardiovascular health, smoking behaviors and food security status were assessed. Smoking cessation knowledge, intention to quit and use of the state quit line were also assessed at follow-up. Of the 144 participants 72.3% reported having hypertension, 34.3% had diabetes, 13.9% had had a stroke. 50.0% were current smokers. The low-intensity intervention significantly increased smoking cessation knowledge but not intention to quit at follow-up. Seven percent of current smokers reported calling the quit line. Current tobacco use was five times more likely in food insecure versus food secure adults (OR 4.98; p = 0.006), even after adjustment for demographic factors. Systems based approaches to address tobacco use and cardiovascular health in low-income populations are needed. The extent to which smoking cessation could reduce food insecurity and risk for cardiovascular disease in this population warrants investigation.