座る時間が長い女性ほど、運動に関わらず、肥満や糖尿病になりやすくなる

●BMI30以下、心臓病およびII型糖尿病，癌のない女性50277人を対象として6年間の調査を行ったところ、7.5%の女性がBMI30を超えて肥満になった。また，1517人がII型糖尿病を発症した。

●これら肥満と糖尿病の発生には，年齢，喫煙習慣，運動量，食生活に関わらず，座位ですごす時間と関連があることが分かった。

●一日に2時間テレビを見る時間を増やす毎に，23%（95% CI,17-30%）の肥満の増加と，14%（95% CI,5-23%）の糖尿病の発症リスクが増加することが分かった。

●また，仕事での座位時間が2時間増加する毎に，5%（95% CI,0-10%）の肥満の増加と，7%（95% CI,0-16%）の糖尿病の増加があることも分かった。

●反対に，立位や家の周りの散歩（2時間/日）は9% (95% CI, 6%-12%)の肥満減少と，12% (95% CI, 7%-16%)の糖尿病リスクの減少と関連があり，また，一日1時間の早歩き(brisk)は24% (95% CI, 19%-29%)の肥満減少と，34% (95% CI, 27%-41%)の糖尿病のリスクを減少させることが分かった。

●テレビを観る時間を週に10時間以内に抑え，かつ一日30分以上の早歩きをすれば，肥満の発生の30% (95% CI, 24%-36%)と糖尿病の発症の43% (95% CI, 32%-52%)を予防できるとしている。

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Television Watching and Other Sedentary Behaviors in Relation to Risk of Obesity and Type 2 Diabetes Mellitus in Women

JAMA. 2003;289(14):1785-1791. doi:10.1001/jama.289.14.1785.

Abstract

Context Current public health campaigns to reduce obesity and type 2 diabetes have largely focused on increasing exercise, but have paid little attention to the reduction of sedentary behaviors. Objective To examine the relationship between various sedentary behaviors, especially prolonged television (TV) watching, and risk of obesity and type 2 diabetes in women. Design, Setting, and ParticipantsProspective cohort study conducted from 1992 to 1998 among women from 11 states in the Nurses' Health Study. The obesity analysis included 50 277 women who had a body mass index (BMI) of less than 30 and were free from diagnosed cardiovascular disease, diabetes, or cancer and completed questions on physical activity and sedentary behaviors at baseline. The diabetes analysis included 68 497 women who at baseline were free from diagnosed diabetes mellitus, cardiovascular disease, or cancer. Main Outcome Measures Onset of obesity and type 2 diabetes mellitus. Results During 6 years of follow-up, 3757 (7.5%) of 50 277 women who had a BMI of less than 30 in 1992 became obese (BMI ≥30). Overall, we documented 1515 new cases of type 2 diabetes. Time spent watching TV was positively associated with risk of obesity and type 2 diabetes. In the multivariate analyses adjusting for age, smoking, exercise levels, dietary factors, and other covariates, each 2-h/d increment in TV watching was associated with a 23% (95% confidence interval [CI], 17%-30%) increase in obesity and a 14% (95% CI, 5%-23%) increase in risk of diabetes; each 2-h/d increment in sitting at work was associated with a 5% (95% CI, 0%-10%) increase in obesity and a 7% (95% CI, 0%-16%) increase in diabetes. In contrast, standing or walking around at home (2 h/d) was associated with a 9% (95% CI, 6%-12%) reduction in obesity and a 12% (95% CI, 7%-16%) reduction in diabetes. Each 1 hour per day of brisk walking was associated with a 24% (95% CI, 19%-29%) reduction in obesity and a 34% (95% CI, 27%-41%) reduction in diabetes. We estimated that in our cohort, 30% (95% CI, 24%-36%) of new cases of obesity and 43% (95% CI, 32%-52%) of new cases of diabetes could be prevented by adopting a relatively active lifestyle (<10 h/wk of TV watching and ≥30 min/d of brisk walking). ConclusionsIndependent of exercise levels, sedentary behaviors, especially TV watching, were associated with significantly elevated risk of obesity and type 2 diabetes, whereas even light to moderate activity was associated with substantially lower risk. This study emphasizes the importance of reducing prolonged TV watching and other sedentary behaviors for preventing obesity and diabetes.

#座る #糖尿病 #肥満 #運動 #女性