Physical Activity of Moderate Intensity and Risk of Type 2 Diabetes

Abstract

OBJECTIVE -To systematically evaluate the evidence for an association between physical activity of moderate intensity and risk of type 2 diabetes. RESEARCH DESIGN AND METHODS -We searched EMBASE and Medline throughMarch 2006 and examined reference lists of retrieved articles. We excluded studies that did not assess physical activity of moderate intensity independent of activities of vigorous intensity (more than six times the resting metabolic rate). Information on study design, participant characteristics, assessment of physical activity, and outcomes and estimates of associations were extracted independently by two investigators. We calculated summary relative risks (RRs) using a random-effects model for the highest versus the lowest reported duration of activities.RESULTS -We identified 10 prospective cohort studies of physical activity of moderate intensity and type 2 diabetes, including a total of 301,221 participants and 9,367 incident cases. Five of these studies specifically investigated the role of walking. The summary RR of type 2 diabetes was 0.69 (95% CI 0.58 -0.83) for regular participation in physical activity of moderate intensity as compared with being sedentary. Similarly, the RR was 0.70 (0.58 -0.84) for regular walking (typically Ն2.5 h/week brisk walking) as compared with almost no walking. The associations remained significant after adjustment for BMI. Similar associations were observed in men and women and in the U.S. and Europe.CONCLUSIONS -These findings indicate that adherence to recommendations to participate in physical activities of moderate intensity such as brisk walking can substantially reduce the risk of type 2 diabetes. Diabetes Care 30:744 -752, 2007T he prevalence of type 2 diabetes is high and expected to increase dramatically in the U.S. and worldwide (1). Type 2 diabetes is a chronic disease associated with premature mortality and various debilitating complications (2). Intensive treatment regimens can prevent some but not all complications (3). Therefore, primary prevention efforts are clearly needed.Moderately intense physical activities, such as walking and gardening, are the most common forms of activity among adults in the U.S. (4) and may be an easily adoptable, relatively safe means to reduce the risk of type 2 diabetes. Randomized trials have shown that physical activity alone or in conjunction with dietary changes can reduce the incidence of type 2 diabetes (5-8). However, the intensity of activity required remains unclear because the independent role of moderately intense activities has not been directly examined in these trials.Observational studies have consistently reported an inverse association between physical activity and type 2 diabetes, but most of these studies focused on vigorous activities or physical activity of various intensities combined (e.g., 9,10). In this article, we systematically review the epidemiological evidence on the association between physical activity of moderate intensity and risk of type 2 diabetes. RESEARCH DESIGN AND METHODS -We s...

Low-intensity physical activity is associated with reduced risk of incident type 2 diabetes in older adults: evidence from the English Longitudinal Study of Ageing

“…This finding is largely consistent with previous work [2,3]. The present study, however, adds to what is already known by showing that there are significant age differences in the association between physical activity and incident type 2 diabetes.…”

“…The current epidemic is largely related to lifestyle factors that are related to obesity and insulin resistance, such as diminished physical activity and increased energy and fat intake. Prospective cohort studies have consistently demonstrated inverse associations between physical activity and risk of type 2 diabetes [2,3]. The protective effect of physical activity becomes apparent even with moderateintensity exercise such as walking [3], and most studies report dose-response associations between physical activity and diabetes risk.…”

“…Prospective cohort studies have consistently demonstrated inverse associations between physical activity and risk of type 2 diabetes [2,3]. The protective effect of physical activity becomes apparent even with moderateintensity exercise such as walking [3], and most studies report dose-response associations between physical activity and diabetes risk. The exact shape of this dose-response association remains uncertain though [4], and the difference in the reduction in risk between the least active and the next least active groups is not always significant [2].…”

Differential relationship between physical activity and progression to diabetes by glucose tolerance status: the Inter99 Study

“…Commuting and leisure-time physical activity are inversely associated with BMI in the Inter99 Study [11], and prospective studies have shown that physical activity can reduce the risk of diabetes independently of BMI or other measures of overweight/obesity [5,6,[37][38][39][40]. However, physical activity may also reduce total body fat and/or its distribution and facilitate weight maintenance, which indirectly reduces the risk of diabetes [35,[40][41][42].…”

“…However, it is unknown whether these results can be extrapolated to individuals with isolated impaired fasting glucose (i-IFG) [4]. Prospective studies have shown that increased levels of physical activity can reduce progression to diabetes [5,6]. Recent population-based studies have examined the relationship between physical activity and overall progression to diabetes [7][8][9].…”