Physical activity associated with reduced risk of diabetes at high CVD risk
Relationship between baseline physical activity assessed by pedometer count and new-onset diabetes in the NAVIGATOR trial
Introduction and methods
Physical activity is related to all-cause mortality, CVD, stroke and diabetes, independently of body mass [1,2], and is therefore an important component of lifestyle intervention studies for CVD [3-6] and diabetes [7-10]. However, the effects of physical activity alone have rarely been investigated in trials in individuals at high risk of CVD or diabetes.
A subanalysis of the Nateglinide and Valsartan in Impaired Glucose Tolerance Outcomes Research (NAVIGATOR)-study  investigated whether physical activity is related to the development of diabetes in subjects with CVD or at high CVD risk.
The NAVIGATOR was a double-blind, randomized, placebo-controlled trial and included individuals with decreased glucose tolerance and with CVD or at high CVD risk, who were randomized to either valsartan or placebo and participated in lifestyle modification programs with a mean follow-up of 6.4 years. At baseline, ambulant physical activity was measured during waking hours by using pedometers for seven consecutive days. In this subanalysis the relation between the number of daily steps at baseline and progression to diabetes was assessed.
The primary outcome was the development of diabetes, defined as fasting plasma glucose levels ≥7,0 mmol/L and glucose levels ≥200 mg/dL (≥11,1 mmol/L) confirmed on oral glucose tolerance test.
- Mean (SD) daily steps at baseline in quartiles were Q1: 1831 (1151), Q2: 4652 (659), Q3: 7096 (800) and Q4: 11.240 (2344). Several biochemical, anthropometric, and behavioral variables of study participants showed significant differences between quartiles.
- 35% of participants developed diabetes during study period.
- After full adjustments, each 2000 extra steps, up to 10.000, was associated with 4% reduced risk of progression to diabetes (HR: 0.96, 95%CI: 0.94-0.99, P<0.0042).
- The interaction between gender and the number of steps was not significantly associated with progression to diabetes.
Physical activity was significantly associated with reduced risk of development of diabetes in patients at high CVD risk, independently of gender. This study shows that measurements of physical activity should be implemented in trials and clinical practice.