The purpose of the current study was to examine associations of individual and aggregated screen-based behaviours, and total sitting time, with healthy and unhealthy dietary intakes among adolescents.

Cross-sectional study of adolescents. Participants self-reported durations of television viewing, computer use, playing electronic games (e-games), total sitting time, daily servings of fruits and vegetables, and frequency of consumption of sugar-sweetened beverages (SSB), diet beverages, fast foods and discretionary snacks. Logistic regression models were conducted to identify associations of screen-based behaviours, total screen time and total sitting time with dietary intakes.

Victoria, Australia.

Adolescents (n 939) in School Year 11 (mean age 16·8 years).

The results showed that watching television (≥2 h/d) was positively associated with consuming SSB and diet beverages each week and consuming discretionary snacks at least once daily, whereas computer use (≥2 h/d) was inversely associated with daily fruit and vegetable intake and positively associated with weekly fast-food consumption. Playing e-games (any) was inversely associated with daily vegetable intake and positively associated with weekly SSB consumption. Total screen (≥2 h/d) and sitting (h/d) times were inversely associated with daily fruit and vegetable consumption, with total screen time also positively associated with daily discretionary snack consumption and weekly consumption of SSB and fast foods.

Individual and aggregated screen-based behaviours, as well as total sitting time, are associated with a number of indicators of healthy and unhealthy dietary intake. Future research should explore whether reducing recreational screen time improves adolescents’ diets.

It has been reported that television (TV) viewing is associated with childhood obesity in Western countries. The present study aimed to investigate the relationship between obesity and eating habits while watching TV among primary-school children in the Middle East.

Cross-sectional.

Children were recruited from primary schools of four educational districts in Shiraz, Iran. Anthropometric indices of mass (kg) and height (m) were measured, and BMI (percentile) was calculated. Demographic characteristics, TV viewing behaviours and physical activity data were collected from parents during face-to-face interviews and a 3d dietary record was completed.

Children (n 607) aged 6–10 years.

Mean (sd) age of children was 8·16 (1·37) years, of whom 9·1 and 8·4 % were overweight and obese, respectively. Children who spent ≥2 h watching TV on weekdays (OR=1·99; 95 % CI 1·09, 3·60) and weekend days (OR=1·86; 95 % CI 1·01, 3·43) had higher odds of being obese, even after adjusting for physical activity. Children who ate breakfast while watching TV had higher odds of being overweight v. those who did not watch TV while eating breakfast (OR=2·70; 95 % CI 1·02, 7·60). There were no associations between TV viewing during other meals (lunch and dinner) and overweight/obesity.

TV viewing for ≥2 h daily increases the risk of being obese in Iranian children aged 6–10 years, independent of physical activity. Further, breakfast consumption while watching TV may increase the risk of overweight/obesity, independent of total TV viewing time.

To determine the frequency and content of food-related television (TV) advertisements shown on South African TV.

Four national TV channels were recorded between 15.00 and 21.00 hours (6 h each day, for seven consecutive days, over a 4-week period) to: (i) determine the number of food-related TV advertisements; and (ii) evaluate the content and approach used by advertisers to market their products. The data were viewed by two of the researchers and coded according to time slots, food categories, food products, health claims and presentation.

Of the 1512 recorded TV advertisements, 665 (44 %) were related to food. Of these, 63 % were for food products, 21 % for alcohol, 2 % for multivitamins, 1 % for slimming products and 13 % for supermarket and pharmacy promotions. Nearly 50 % of food advertisements appeared during family viewing time. During this time the most frequent advertisements were for desserts and sweets, fast foods, hot beverages, starchy foods and sweetened drinks. The majority of the alcohol advertisements (ninety-three advertisements, 67 %) fell within the children and family viewing periods and were endorsed by celebrities. Health claims were made in 11 % of the advertisements. The most frequently used benefits claimed were ‘enhances well-being’, ‘improves performance’, ‘boosts energy’, ‘strengthens the immune system’ and ‘is nutritionally balanced’.

The majority of food advertisements shown to both children and adults do not foster good health despite the health claims made. The fact that alcohol advertisements are shown during times when children watch TV needs to be addressed.

The main objective was to assess the relationship of breakfast skipping, television (TV) viewing at breakfast and breakfast without TV with weight status among parents of 10–12-year-olds in eight European countries.

A cross-sectional survey assessed breakfast eating and TV viewing at breakfast by three frequency questions and parents were categorized into: (i) breakfast skippers; (ii) breakfast with TV (TV watchers at breakfast); and (iii) breakfast without TV (breakfast eaters who do not watch TV during breakfast). Self-reported weight and height were used to categorize weight status as underweight, normal weight, overweight and obese. Multinomial logistic regression analyses were conducted with weight status as the dependent variable and breakfast habits as predictors, adjusting for sex, ethnicity and level of education.

The survey was conducted in 2010 in 199 primary schools across eight European countries participating in the ENERGY (EuropeaN Energy balance Research to prevent excessive weight Gain among Youth) cross-sectional study.

Parents (n 6512) of 10–12-year-olds responded to the questionnaire.

In the total study sample, with breakfast without TV as the reference group and adjusting for sex, ethnicity and level of education, the OR of being respectively overweight or obese (compared with normal weight) was 1·2 (95 % CI 1·0, 1·4) or 1·8 (95 % CI 1·5, 2·3) for breakfast skippers. The OR of being respectively underweight or obese was 0·5 (95 % CI 0·2, 0·9) or 1·4 (95 % CI 1·1, 1·8) for breakfast with TV.

Breakfast skippers were significantly more likely to be overweight and obese, and those eating breakfast while watching TV were significantly more likely to be obese and less likely to be underweight.

To examine whether home availability of energy-dense snack foods mediates the association between television (TV) viewing and energy-dense snack consumption among adolescents.

Cross-sectional.

Secondary schools in Victoria, Australia.

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.

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.

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.

To assess the association of time spent viewing television, videos and video games with measures of fat mass (BMI) and distribution (triceps and subscapular skinfold thicknesses (TSF, SSF)).

Cross-sectional validated survey, self-administered to students to assess screen time (television, videos and video games) and lifestyle variables. Trained personnel obtained anthropometry. The association of screen time with fat mass and distribution, stratified by sex, was modelled with multivariable linear regression analysis, adjusting for potential confounders and correlation of observations within schools.

State of Morelos, Mexico.

Males (n 3519) and females (n 5613) aged 11 to 18 years attending urban and rural schools in Morelos.

In males, screen time of >5 h/d compared with <2 h/d was significantly associated with a 0·13 (95 % CI 0·04, 0·23) higher BMI Z-score, 0·73 mm (95 % CI 0·24, 1·22) higher SSF and 1·08 mm (95 % CI 0·36, 1·81) higher TSF. The positive association of screen time with SSF was strongest in males aged 11–12 years. Sexual maturity appeared to modify the association in females; a positive association between screen time and SSF was observed in those who had not undergone menarche (P for trend = 0·04) but not among sexually mature females (P for trend = 0·75).

Screen time is associated with fat mass and distribution among adolescent males in Mexico. Maturational tempo appears to affect the relationship of screen time with adiposity in boys and girls. Findings suggest that obesity preventive interventions in the Mexican context should explore strategies to reduce screen time among youths in early adolescence.

To examine whether eating while watching television poses a risk for poor nutrition and excess body weight over and above that of time spent watching television.

We analysed data of grade 5 students participating in a comprehensive population-based survey in the Canadian province of Nova Scotia. This survey included the Harvard’s Youth Food Frequency Questionnaire, students’ height and weight measurements, and a parent survey. We applied multivariable linear and logistic random effects models to quantify the associations of watching television and eating while watching television with diet quality and body weight.

The province of Nova Scotia, Canada.

Grade 5 students (n 4966).

Eating supper while watching television negatively affected the consumption of fruits and vegetables and overall diet quality. More frequent supper while watching television was associated with more soft drink consumption, a higher percentage energy intake from sugar out of total energy from carbohydrate, a higher percentage energy intake from fat, and a higher percentage energy intake from snack food. These associations appeared independent of time children spent watching television. Both watching television and eating while watching television were positively and independently associated with overweight.

Our observations suggest that both sedentary behaviours from time spent watching television as well as poor nutrition as a result of eating while watching television contribute to overweight in children. They justify current health promotion targeting time spent watching television and call for promotion of family meals as a means to avoid eating in front of the television.

The present paper examines the relationship between social factors, food consumption during television viewing, and overall television viewing and how these are associated with BMI when the role of familial and social factors are considered in a population-based birth cohort of pre-school children from Québec (Canada).

The analyses were performed using data from the Longitudinal Study of Child Development in Québec (1998–2002) (LSCDQ). The study follows a representative sample (n 2103) of children born in 1998 in the Canadian province of Québec. A nutrition assessment was conducted on 1549 children aged 4·5 years and included a 24 h dietary recall, an eating behaviour and television viewing questionnaire, and a measurement of children’s heights and weights. Statistical analyses were performed.

Nearly one-quarter of children ate at least twice daily in front of the television. Children who consumed snacks while watching television on a daily basis had higher BMI than children who did so less frequently. Children who ate snacks in front of the television every day, or some times during the week, ate more carbohydrates (total), more fat and less protein, fewer fruits and vegetables, and drank soft drinks more often than children who never ate snacks in front of the television.

Health professionals should target parents of children at risk of overweight/obesity with focused strategies to help children change the types of foods consumed during television viewing and to reduce the time spent watching television, particularly during meal times, which may change children’s dietary intake and eating patterns.

To examine the relationship between television (TV) viewing and body mass index (BMI) among adolescents in a region of mainland China.

Population-based cross-sectional study, conducted between September and November of 2004, on a sample of enrolled high-school students aged 12–18 years.

One hundred and sixty-eight classes randomly selected from both urban and rural areas and belonging to 15 senior and 41 junior high schools in Nanjing, China, with a regional population of 6·0 million.

In total 6848 students participated; 47·7 % from urban and 52·3 % from rural areas; 49·0 % male and 51·0 % female. The response rate among eligible participants was 89·3 %.

The proportion of overweight was 6·6 % according to the criteria of overweight recommended for Chinese adolescents. Boys than girls (8·9 % vs. 4·4 %) had higher odds of being overweight (odds ratio (OR) 2·12, 95 % confidence interval (CI) 1·74, 2·60), while the proportion of overweight was significantly lower among rural students than urban students (4·5 % vs. 8·9 %; OR 0·49, 95 % CI 0·40, 0·60). Those students who watched TV for more than 7 h/week had a 1·5 times greater odds of being overweight relative to their counterparts who watched TV for 7 h/week or less (adjusted OR 1·51, 95 % CI 1·24, 1·82). Furthermore, there was a positive linear relationship between TV viewing time and BMI, even after adjusting for age, gender, residence area, time spent in study, in sleeping and in physical activity, and monthly pocket money.

Viewing TV might increase the likelihood of being overweight for Chinese adolescents in China.

To describe obesity among students of public schools in São Paulo and to identify risk factors for this nutritional and physical activity disorder.

Case– control study of obese and non-obese schoolchildren to study risk factors for obesity.

Anthropometric survey including 2519 children attending eight elementary public schools in Sã o Paulo, Brazil.

Schoolchildren aged 7–10 years, of whom 223 were obese (cases; weight-for-height greater than or equal to two standard deviations(≥2SD) above the median of the National Center for Health Statistics (NCHS) reference population) and 223 were eutrophic (controls; weight-for-height ±1SD from NCHS median).

Parents or guardians of the 446 cases and controls were interviewed about the children's eating behaviours and habits.

The prevalence of obesity (weight-for-height ≥2SD) in the surveyed population was 10.5%. A logistic regression model fitted to the case–control dataset showed that obesity was positively associated with the following factors: birth weight ≥3500 g (odds ratio (OR) 1.83, 95% confidence interval (CI) 1.21–2.78), child's appetite at meals (OR 3.81, 95% CI 2.49–5.83), watching television for 4h per day or longer (OR 2.07, 95% CI 1.32–3.24), mother's schooling>4 years (OR 1.85, 95% CI 1.25–2.75) and parents' body mass index ≥ 30 kgm−2(OR 2.50, 95% CI 1.43–4.37).

The explanatory multivariate model points to preventive measures that would encourage knowledge of the children and their guardians in relation to a balanced diet and a less sedentary lifestyle, such as reducing television viewing. Schoolchildren with a birth weight of 3500g or more or whose parents are obese should receive special attention in the prevention of obesity.