Time spent taking part in moderate and vigorous physical activity (MVPA) improves indicators of insulin resistance independently of time spent sedentary, taking part in light-intensity activity, and TV viewing, report researchers in the journal Diabetes Care.

Low levels of physical activity are associated with insulin resistance, which is an independent predictor for Type 2 diabetes even in people with normal glucose levels.

Ulf Ekelund (University of Cambridge, UK) and colleagues examined whether time spent sedentary, at light-intensity activity, at MVPA, and TV viewing predict future insulin resistance in people at high risk for Type 2 diabetes.

This information is important as while existing guidelines on physical activity emphasize the importance of MVPA, they do not consider the potential harmful effects of sedentary living.

The researchers measured physical activity and anthropometric and metabolic variables at baseline and after 1 year of follow-up in 192 individuals with a family history of Type 2 diabetes taking part in the ProActive UK trial.

As it is difficult to accurately capture light-intensity activity or total sedentary behavior by questionnaire, physical activity was measured objectively by accelerometry. Insulin resistance was expressed as fasting insulin and the homeostasis model assessment score (HOMA-IR).

The authors report that baseline MVPA was a significant predictor of fasting insulin at follow-up and that the association approached significance for HOMA-IR, independently of time spent sedentary or involved in light-intensity activity, gender, age, smoking status, waist circumference, and self-reported TV viewing.

Time spent sedentary and at light-intensity activity were not significantly associated with insulin resistance.

The authors also found that change in MVPA was significantly and inversely related to the change in fasting insulin and the HOMA score after adjustment for baseline characteristics, TV viewing, and follow-up time.

In addition, an increase in MVPA over 1 year was associated with improved insulin sensitivity.

“These results highlight the importance of promoting moderate-intensity activity such as brisk walking to improve insulin sensitivity and other metabolic risk factors and to prevent Type 2 diabetes, at least in individuals with a high risk of developing this disease,” conclude the authors.

MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a part of Springer Science+Business Media. © Current Medicine Group Ltd; 2009

Free abstract

Meta-analysis results published in The Lancet show that intensive glucose control in patients with Type 2 diabetes significantly reduces nonfatal myocardial infarction (MI) and other coronary heart disease (CHD) related events compared with standard glucose control, with no effect on all-cause mortality.

“Previous studies have been inconclusive, leaving diabetics and their doctors unsure as to whether maintaining lower blood sugar levels actually benefitted the patients,” said lead study author Kausik Ray (University of Cambridge, UK).

“Although additional research needs to be conducted, our findings provide insight into the importance of improving glucose levels which should include lifestyle changes as well as medication.”

The researchers selected five prospective randomized trials ??” UKPDS, PROactive, ADVANCE, VADT, and ACCORD ??” for inclusion in the meta-analysis, including a total of 33,040 participants.

All five studies compared the effects of intensive (average achieved glycated hemoglobin [HbA1c] level of 6.6%) versus standard glucose control (mean achieved HbA1c of 7.5%) on death and cardiovascular outcomes.

Overall, there were 1497 nonfatal MIs, 2318 CHD events, 1127 strokes, and 2892 deaths from any cause over an average follow-up period for the five trials of 4.95 years.

Ray and team found that compared with a standard treatment regimen, intensive glycemic control reduced the incidence of non-fatal MI by 17% and CHD events by 15%.

There were no significant effects on incidence of stroke (7% reduction) or all-cause mortality (no difference) recorded between intensive and standard treatment groups.

Theodore Mazzone (University of Illinois, Chicago, USA) pointed out in an accompanying editorial that the benefits of intensive glucose control on the incidence of CHD events “will certainly not be as great as that produced by blood pressure control or statin treatment.”

However, he added that “on the basis of current information, and the urgent need to address residual risk of CHD in a rapidly expanding population with Type 2 diabetes, it is premature to conclude that glucose control has no part to play.”

MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a part of Springer Science+Business Media. © Current Medicine Group Ltd; 2009

Free abstract