Effects of tv time and other sedentary pursuits

Television (TV) viewing is the dominant recreational pastime at all ages, especially for children and adolescents. Many studies have shown that higher TV viewing hours are associated with higher body mass index (BMI), lower levels of fitness and higher blood cholesterol levels. Although the effect size estimated from observational studies is small (with TV viewing explaining very little of the variance in BMI), the results of intervention studies show large effect sizes. The potential mediators of the effect of higher TV viewing on higher BMI include less time for physical activity, reduced resting metabolic rate (for which there is little supporting evidence) and increased energy intake (from more eating while watching TV and a greater exposure to marketing of energy dense foods). Electronic games may have an effect on unhealthy weight gain, but are less related to increased energy intake and their usage is relatively new, making effect size difficult to determine. Thus, TV viewing does not explain much of the differences in body size between individuals or the rise in obesity over time, perhaps because of the uniformly high, but relatively stable, TV viewing hours. Reducing TV viewing hours is a difficult prospect because potential actions, such as social marketing and education, are likely to be relatively weak interventions, although the evidence would suggest that, if viewing could be reduced, it could have a significant impact on reducing obesity prevalence. Regulations to reduce the heavy marketing of energy dense foods and beverages on TV may be the most effective public health measure available to minimize the impact of TV viewing on unhealthy weight gain.

Is television viewing time a marker of a broader pattern of sedentary behavior?

Background: Television (TV) viewing time is associated with abnormal glucose metabolism, the metabolic syndrome, and risk of type 2 diabetes; associations are stronger and more consistent in women. One explanation of this difference may be that TV viewing is a marker of an overall pattern of sedentary behavior in women.

Purpose: We sought to examine associations of TV viewing time with other sedentary behaviors and with leisure-time physical activity in a large sample of Australian adults.

Methods: Adults aged between 20 and 65 years (n=2,046) completed a  self-administered questionnaire on TV viewing, five other leisure-time sedentary behaviors, and leisure-time physical activity. Mean adjusted time spent in other sedentary behaviors and in physical activity was compared across TV-time  categories previously shown to be associated with abnormal glucose  metabolism.

Results: After adjustment for body mass index and sociodemographic variables, women’s time spent watching TV was associated positively with time in other sedentary behaviors and negatively with leisure-time physical activity, but no such associations were observed in men.

Conclusions: TV viewing time may be a robust marker of a sedentary lifestyle in women but not in men. Gender differences in the pattern of sedentary behaviors may explain at least in part the gender differences in the previously reported associations of TV viewing time with biological attributes related to type 2   diabetes.

Television viewing and abdominal obesity in young adults : is the association mediated by food and beverage consumption during viewing time or reduced leisure-time physical activity?

BACKGROUND:The behavioral pathways through which television (TV) viewing leads to increased adiposity in adults are unclear.

OBJECTIVE:We wanted to determine whether the association between TV viewing and abdominal obesity in young adults is mediated by food and beverage consumption during TV viewing time or by a reduction in overall leisure-time physical activity (LTPA).

DESIGN:This study involved a cross-sectional analysis of data from 2001 Australian adults aged 26–36 y. Waist circumference (WC) was measured at study clinics, and TV viewing time, frequency of food and beverage consumption during TV viewing, LTPA, and demographic characteristics were self-reported.

RESULTS:Women watching TV >3 h/d had a higher prevalence of severe abdominal obesity (WC: =88 cm) compared with women watching =1 h/d [prevalence ratio (PR): 1.89; 95% CI: 1.32, 2.71]. Moderate abdominal obesity (WC: 94–101.9 cm) was more prevalent in men watching TV >3 h/d than in men watching =1 h/d (PR: 2.16; 95% CI: 1.37, 3.41). Adjustment for LTPA made little difference, but adjustment for food and beverage consumption during TV viewing attenuated the associations (PR: 1.48; 95% CI: 1.01, 2.17 for women; PR: 1.73; 95% CI: 1.06, 2.83 for men).

CONCLUSIONS:The association between TV viewing and WC in young adults may be partially explained by food and beverage consumption during TV viewing but was not explained by a reduction in overall LTPA. Other behaviors likely contribute to the association between TV viewing and obesity.

Deleterious associations of sitting time and television viewing time with cardiometabolic risk biomarkers

We examined the associations of sitting time and television (TV) viewing time with continuously measured biomarkers of cardio-metabolic risk in Australian adults. Waist circumference, BMI, resting blood pressure, triglycerides, HDL cholesterol, fasting and 2-h postload plasma glucose, and fasting insulin were measured in 2,761 women and 2,103 men aged ≥30 years (mean age 54 years) without clinically diagnosed diabetes from the 2004-2005 Australian Diabetes, Obesity and Lifestyle (AusDiab) study. Multivariate linear regression analyses examined associations of self-reported sitting time and TV viewing time (hours per day) with these biomarkers, adjusting for potential confounding variables. For both women and men, sitting time was detrimentally associated with waist circumference, BMI, systolic blood pressure, fasting triglycerides, HDL cholesterol, 2-h postload plasma glucose, and fasting insulin (all P < 0.05), but not with fasting plasma glucose and diastolic blood pressure (men only). With the exception of HDL cholesterol and systolic blood pressure in women, the associations remained significant after further adjustment for waist circumference. TV viewing time was detrimentally associated with all metabolic measures in women and all except HDL cholesterol and blood pressure in men. Only fasting insulin and glucose (men only) remained deleteriously associated with TV viewing time after adjustment for waist circumference. In women and men, sitting time and TV viewing time were deleteriously associated with cardio-metabolic risk biomarkers, with sitting time having more consistent associations in both sexes and being independent of central adiposity. Preventive initiatives aimed at reducing sitting time should focus on both nonleisure and leisure-time domains.

Identifying subgroups of U.S. adults at risk for prolonged television viewing to inform program development

Background
Although adverse health effects of prolonged TV viewing have been increasingly recognized, little population-wide information is available concerning subgroups at greatest risk for this behavior.

Purpose
This study sought to identify, in a U.S. population–derived sample, combinations of variables that defined subgroups with higher versus lower levels of usual TV-viewing time.

Methods
A total of 5556 adults from a national consumer panel participated in the mail survey in 2001 (55% women, 71% white, 13% black, and 11% Hispanic). Nonparametric risk classification analyses were conducted in 2008.

Results
Subgroups with the highest proportions of people watching >14 hours/week of TV were identified and described using a combination of demographic (i.e., lower household incomes, divorced/separated); health and mental health (i.e., poorer rated overall health, higher BMI, more depression); and behavioral (i.e., eating dinner in front of the TV, smoking, less physical activity) variables. The subgroup with the highest rates of TV viewing routinely ate dinner while watching TV and had lower income and poorer health. Prolonged TV viewing also was associated with perceived aspects of the neighborhood environment (i.e., heavy traffic and crime, lack of neighborhood lighting, and poor scenery).

Conclusions
The results can help inform intervention development in this increasingly important behavioral health area.

Mediators of longitudinal associations between television viewing and eating behaviours in adolescents

Background: Television viewing has been associated with poor eating behaviours in adolescents. Changing unhealthy eating behaviours is most likely to be achieved by identifying and targeting factors shown to mediate the association between these behaviours. However, little is known about the mediators of the associations between television viewing and eating behaviours. The aim of this study was to examine mediators of the longitudinal associations between television viewing (TV) and eating behaviours among Australian adolescents.
Method: Eating behaviours were assessed using a web-based survey completed by a community-based sample of 1729 adolescents from years 7 and 9 of secondary schools in Victoria, Australia, at baseline (2004-2005) and two years later. TV viewing and the potential mediators (snacking while watching TV and perceived value of TV viewing) were assessed via the web-based survey at baseline.
Results: Adolescents who watched more than two hours of TV/day had higher intakes of energy-dense snacks and beverages, and lower intakes of fruit two years later. Furthermore, the associations between TV viewing and consumption of energy-dense snacks, energy-dense drinks and fruit were mediated by snacking while watching TV. Perceived value of TV viewing mediated the association between TV viewing and consumption of energy-dense snacks, beverages and fruit.
Conclusion: Snacking while watching TV and perceived value of TV viewing mediated the longitudinal association between TV viewing and eating behaviours among adolescents. The efficacy of methods to reduce TV viewing, change snacking habits while watching TV, and address the values that adolescents place on TV viewing should be examined in an effort to promote healthy eating among adolescents.

The association between television viewing and preschool child body mass index : a systematic review of english papers published from 1995 to 2010

This paper is a conceptual and methodological review of the literature on the impact of TV on preschoolers' weight status. A systematic search, of papers published between January 1995 and January 2010, identified twenty-six relevant studies. Fifteen of these were cross-sectional in design and eleven adopted a prospective design; a positive association between hours of TV and child adiposity was found in all but three studies. Although assessed in a limited number of studies, diet may mediate the relationship between TV viewing and BMI. Another likely mediator may be the content of TV programs watched; only three studies examined this association and findings were inconsistent. Our review revealed that research examining mediating effects is limited, focusing more on simple cross-sectional or prospective relationships between TV habits and child body mass index. Further investigation of the mechanisms by which TV viewing affects preschool weight gain is needed.

Correlates of change in adults’ television viewing time : a four-year follow-up study

Purpose: Adults tend to increase their television (TV) viewing time as they age, but little is known about attributes associated with change in TV viewing over time. This study examined individual, social, and environmental correlates of change in TV viewing time for 4 yr.

Methods: Adult participants (n = 897) from a longitudinal epidemiological study in Adelaide, Australia, reported TV viewing time at baseline (2003–2004) and at follow- up (2007–2008). Generalized linear modeling was used to examine correlates of change in TV viewing time.

Results: The mean TV viewing time increased from 112 to 116 min·d-1 from baseline to follow-up. Adjusted for TV viewing time at baseline, having a tertiary education was associated with a 13% lower TV time at follow-up (P = 0.007). Each additional hour of occupational and transport physical activity at baseline was associated with a 2% and 7% lower TV viewing at follow-up (P = 0.031 and P = 0.023, respectively). For men, an additional hour of domestic physical activity was associated with a 7% higher TV viewing time at follow-up (P = 0.006). A significant neighborhood walkability × working status interaction (P = 0.035) indicated that, for those who were not working, living in a highly walkable neighborhood was associated with a 23% lower TV viewing time at follow-up (P = 0.003).

Conclusions: Adults with lower educational attainment, adults with lower occupational and transport physical activity, men with higher domestic physical activity, and nonworking adults living in lowly walkable neighborhoods were at higher risk of increase in TV viewing time. Interventions should target multiple variables at the individual, social, and environmental levels to address age-related increases in TV viewing time.

Adolescent television viewing and unhealthy snack food consumption: the mediating role of home availability of unhealthy snack foods

Objective
To examine whether home availability of energy-dense snack foods mediates the association between television (TV) viewing and energy-dense snack consumption among adolescents.
Design
Cross-sectional.
Setting
Secondary schools in Victoria, Australia.
Subjects
Adolescents (n 2984) from Years 7 and 9 of secondary school completed a web-based survey, between September 2004 and July 2005, assessing their energy-dense snack food consumption, school-day and weekend-day TV viewing and home availability of energy-dense snack foods.
Results
School-day and weekend-day TV viewing were positively associated with energy-dense snack consumption among adolescent boys (β = 0·003, P < 0·001) and girls (β = 0·03, P < 0·001). Furthermore, TV viewing (school day and weekend day) were positively associated with home availability of energy-dense snack foods among adolescent boys and girls and home availability of energy-dense snack foods was positively associated with energy-dense snack food consumption among boys (β = 0·26, P < 0·001) and girls (β = 0·28, P < 0·001). Home availability partly mediated the association between TV viewing and energy-dense snack consumption.
Conclusions
The results of the present study suggest that TV viewing has a significant role to play in adolescent unhealthy eating behaviours. Future research should assess the efficacy of methods to reduce adolescent energy-dense snack food consumption by targeting parents to reduce home availability of energy-dense foods and by reducing TV viewing behaviours of adolescents.

Associations of television viewing time with adults' well-being and vitality

Television (TV) viewing, a common leisure-time sedentary behaviour, is associated adversely with cardio-metabolic health, fatigue, depression and mental health. However, associations of TV viewing time with health-related quality of life attributes are less well understood. We examined associations of TV viewing time with physical well-being, mental well-being and vitality in a large population-based sample of Australian adults.

Physical activity, television viewing time and 12 year changes in waist circumference

PURPOSE: Both moderate-to-vigorous physical activity (MVPA) and sedentary behavior can be associated with adult adiposity. Much of the relevant evidence is from cross-sectional studies or from prospective studies with relevant exposure measures at a single time point prior to weight gain or incident obesity. This study examined whether changes in MVPA and television (TV) viewing time are associated with subsequent changes in waist circumference, using data from three separate observation points in a large population-based prospective study of Australian adults. METHODS: Data were obtained from the Australian Diabetes, Obesity and Lifestyle study collected in 1999-2000 (baseline), 2004-05 (Wave 2), and 2011-12 (Wave 3). The study sample consisted of adults aged 25 to 74 years at baseline who also attended site measurement at three time points (n=3261). Multilevel linear regression analysis examined associations of initial five-year changes in MVPA and TV viewing time (from baseline to Wave 2) with 12-year change in waist circumference (from baseline to Wave 3), adjusting for well-known confounders. RESULTS: As categorical predictors, increases in MVPA significantly attenuated increases in waist circumference (p for trend< 0.001). TV viewing time change was not significantly associated with changes in waist circumference (p for trend =0.06). Combined categories of MVPA and TV viewing time changes were predictive of waist circumference increases; compared to those who increased MVPA and reduced TV viewing time, those who reduced MVPA and increased TV viewing time had a 2cm greater increase in waist circumference (p=0.001). CONCLUSION: Decreasing MVPA emerged as a significant predictor of increases in waist circumference. Increasing TV viewing time was also influential, but its impact was much weaker than MVPA.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially.

An Architecture for End-User TV Content Enrichment

This paper proposes an extension to the televisionwatching paradigm that permits an end-user to enrich broadcast content. Examples of this enriched content are: virtual edits that allow the order of presentation within the content to be changed or that allow the content to be subsetted; conditional text, graphic or video objects that can be placed to appear within content and triggered by viewer interaction; additional navigation links that can be added to structure how other users view the base content object. The enriched content can be viewed directly within the context of the TV viewing experience. It may also be shared with other users within a distributed peer group. Our architecture is based on a model that allows the original content to remain unaltered, and which respects DRM restrictions on content reuse. The fundamental approach we use is to define an intermediate content enhancement layer that is based on the W3C’s SMIL language. Using a pen-based enhancement interface, end-users can manipulate content that is saved in a home PDR setting. This paper describes our architecture and it provides several examples of how our system handles content enhancement. We also describe a reference implementation for creating and viewing enhancements.

Television viewing, C-reactive protein, and depressive symptoms in older adults

There is emerging evidence for a link between sedentary behavior and mental health, although the mechanisms remain unknown. We tested if an underlying inflammatory process explains the association between sedentary behavior and depressive symptoms. We conducted a two year follow-up of 4964 (aged 64.5 ± 8.9 years) men and women from the English Longitudinal Study of Ageing, a cohort of community dwelling older adults. Self-reported TV viewing time was assessed at baseline as a marker of leisure time sedentary behavior. The eight-item Centre of Epidemiological Studies Depression (CES-D) scale was administered to measure depressive symptoms at follow-up. At baseline, TV time was associated with C-reactive protein (CRP), adjusted geometric mean CRP values were 2.94 mg/L (<2 h/d TV); 3.04 mg/L (2–4 h/d TV); 3.29 mg/L (4–6 h/d TV); 3.23 mg/L (>6 h/d TV). We observed both a direct association of TV time on CES-D score at follow-up (B = 0.08, 95% CI, 0.05, 0.10) and indirect effects (B = 0.07, 95% CI, 0.05, 0.08). The indirect effects were largely explained through lack of physical activity, smoking, and alcohol, but not by CRP or body mass index.

Television viewing time and 13-year mortality in adults with cardiovascular disease: data from the Australian Diabetes, Obesity and Lifestyle Study (AusDiab)

BACKGROUND: In the general population, excessive sedentary behaviour is associated with increased all-cause mortality. Few studies have examined this relationship in people with cardiovascular disease (CVD). Using a sample of people with CVD who were excluded from an analysis of the Australian Diabetes, Obesity and Lifestyle (AusDiab) study, we examined the relationship between sedentary behaviour and 13-year all-cause mortality.

METHODS: In the original AusDiab study, television viewing time was used as a marker of sedentary behaviour in 609 adults (≥45 years of age) with CVD. During 6,291 person-years of follow-up (median follow-up 13 years), there were 294 deaths (48% of sample). Using the time scale of attained age, the Cox proportional hazards model predicting all-cause mortality adjusted for sex, self-rated general health, leisure-time physical activity, smoking status, education, household income, body mass index, lipid levels, blood pressure, and diabetes mellitus was used.

RESULTS: Compared with a TV viewing time of <2hours per day, the fully adjusted hazard ratios for all-cause mortality were 1.18 (95% CI, 0.88 to 1.57) for ≥2 to <4hours per day and 1.52 (95% CI, 1.09 to 2.13) for >4hours per day.

CONCLUSIONS: Sedentary behaviour was associated with increased risk of all-cause mortality in people with CVD, independent of physical activity and other confounders. In addition to the promotion of regular physical activity, cardiac rehabilitation efforts which also focus on reducing sedentary behaviour may be beneficial.

It's time to be more serious about activating youngsters : lessons for childhood obesity

The epidemic of obesity is impacting an increasing proportion of children, adolescents and adults with a common feature being low levels of physical activity (PA). Despite having more knowledge than ever before about the benefits of PA for health and the growth and development of youngsters, we are only paying lip-service to the development of motor skills in children. Fun, enjoyment and basic skills are the essential underpinnings of meaningful participation in PA. A concurrent problem is the reported increase in sitting time with the most common sedentary behaviors being TV viewing and other screen-based games. Limitations of time have contributed to a displacement of active behaviors with inactive pursuits, which has contributed to reductions in activity energy expenditure. To redress the energy imbalance in overweight and obese children, we urgently need out-of-the-box multisectoral solutions. There is little to be gained from a shame and blame mentality where individuals, their parents, teachers and other groups are singled out as causes of the problem. Such an approach does little more than shift attention from the main game of prevention and management of the condition, which requires a concerted, whole-of-government approach (in each country). The failure to support and encourage all young people to participate in regular PA will increase the chance that our children will live shorter and less healthy lives than their parents. In short, we need novel environmental approaches to foster a systematic increase in PA. This paper provides examples of opportunities and challenges for PA strategies to prevent obesity with a particular emphasis on the school and home settings.