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OBJECTIVE -We examined the associations of television viewing time with fasting plasma glucose (FPG) and 2-h postchallenge plasma glucose (2-h PG) levels in Australian adults. RESEARCH DESIGN AND METHODS-A total of 8,357 adults aged Ͼ35 years who were free from diagnosed diabetes and who attended a population-based cross-sectional study (Australian Diabetes, Obesity and Lifestyle Study [AusDiab]) were evaluated. Measures of FPG and 2-h PG were obtained from an oral glucose tolerance test. Self-reported television viewing time (in the previous week) was assessed using an interviewer-administered questionnaire. Homeostasis model assessment (HOMA) of insulin sensitivity (HOMA-%S) and ␤-cell function (HOMA-%B) were calculated based on fasting glucose and insulin concentrations.RESULTS -After adjustment for confounders and physical activity time, time spent watching television in women was positively associated with 2-h PG, log fasting insulin, and log HOMA-%B and inversely associated with log HOMA-%S (P Ͻ 0.05) but not with FPG. No significant associations were observed with glycemic measures in men. The ␤-coefficients across categories of average hours spent watching television per day (Ͻ1.0, 1.0 -1.9, 2.0 -2.9, 3.0 -3.9, and Ն4.0) for 2-h PG in women were 0 (reference), 0.009, 0.047, 0.473, and 0.501, respectively (P for trend ϭ 0.02).CONCLUSIONS -Our findings highlight the unique deleterious relationship of sedentary behavior (indicated by television viewing time) and glycemic measures independent of physical activity time and adiposity status. These relationships differed according to sex and type of glucose measurement, with the 2-h PG measure being more strongly associated with television viewing. The findings suggest an important role for reducing sedentary behavior in the prevention of type 2 diabetes and cardiovascular disease, especially in women. Diabetes Care 30:516 -522, 2007P hysical inactivity increases the risk of many chronic diseases, including type 2 diabetes (1). Recently, several studies have shown that sedentary behavior, as distinct from lack of physical activity (2), may be an important contributor to poor health outcomes (3-8). Television viewing time, which is a major leisure-time sedentary behavior in Australia (9), has been linked to obesity and to type 2 diabetes in adults, independent of physical activity levels (7,8). In addition, our previous work has shown independent positive associations between television viewing time and categories of glucose intolerance. However, since fasting plasma glucose (FPG) and 2-h postchallenge plasma glucose (2-h PG) differ from each other in their respective physiological determinants (10) and in the risks that they carry (11), there is a need to investigate the influence of television viewing on plasma glucose across the glucose continuum from normal to diabetes levels. While some cross-sectional studies have found that television viewing time is positively associated with FPG in adults (3,12), no population-based studies have investigated the extent ...

Recent epidemiological evidence suggests that prolonged sitting (sedentary behaviour: time spent in behaviours that have very low energy expenditure, such as television viewing and desk-bound work) has deleterious cardiovascular and metabolic correlates, which are present even among adults who meet physical activity and health guidelines. Further advances in communication technology and other labour-saving innovations make it likely that the ubiquitous opportunities for sedentary behaviour that currently exist will become even more prevalent in the future. We present evidence that sedentary behaviour (too much sitting) is an important stand-alone component of the physical activity and health equation, particularly in relation to cardio-metabolic risk, and discuss whether it is now time to consider public health and clinical guidelines on reducing prolonged sitting time that are in addition to those promoting regular participation in physical activity.

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