Television viewing time in Hong Kong adult population: Associations with body mass index and obesity

Background: Obesity is increasing dramatically in the Asia-Pacific region particularly China. The population of Hong Kong was exposed to modernization far earlier than the rest of China, reflecting conditions that are likely to be replicated as other Chinese cities undergo rapid change. This study examined the relationship between television viewing and obesity in a Hong Kong sample. Information about the relationship between a key sedentary behavior, TV viewing, and obesity, and its moderation by demographic characteristics may identify sectors of the population at highest risk for excess weight. Methods: Data were from Hong Kong Family and Health Information Trends Survey (2009-2010), a population-based survey on the public's use of media for health information and family communication by telephone interviews with 3,016 Hong Kong adults (age≥18 years). TV viewing time, body mass index (BMI), physical activity and other lifestyle variables were analyzed. Results: Viewing time was longer in women, increased with age but decreased with education level and vigorous physical activity (all P<0.01). Longer TV viewing time was significantly associated with higher BMI (Coefficients B = 0.17, 95% CI: 0.11, 0.24) after adjusting for age, gender, employment status, marital status, education level, smoking activity and vigorous physical activity. This association was stronger in women than men (Coefficients B: 0.19 versus 0.15) and strongest in those aged 18 to 34 years (Coefficients B = 0.35). Furthermore, an hour increase in daily TV viewing was associated with 10% greater odds of being obese. Conclusions: A significant socioeconomic gradient in television viewing time was observed. TV viewing time positively associated with BMI and obesity. The TV viewing - BMI associations were strongest in women and young adults, suggesting vulnerable groups to target for obesity prevention by decreasing TV viewing.