Effect of physical activity measurement type on the association between walking activity and glucose regulation in a high-risk population recruited from primary care

Abstract

We investigate associations of self-reported and objectively assessed walking activity with measures of glucose regulation in a multi-ethnic population at high risk of type 2 diabetes. This study reports data from a 2009-2011 screening programme for impaired glucose regulation (IGR) within a high-risk primary care population in Leicestershire, UK; 2532 participants (38% women, 8% South Asian) with a mean age of 64 ± 8 years and an average BMI of 32.1 ± 5.6 kg/m(2) were included. Walking activity was measured by self-report (International Physical Activity Questionnaire) and objectively (pedometer). Glucose regulation assessments included 2h post-challenge glucose, fasting glucose and HbA1c. Higher levels of self-reported walking activity and pedometer steps were associated with lower 2h post-challenge glucose after controlling for several known confounding variables, including BMI. Similarly, when categorized in tertiles, both measures were associated with a lower odds of having any form of IGR; odds ratio for lowest vs highest tertile was 0.64 (0.51-0.80) for self-report and 0.69 (0.55-0.87) for pedometer steps. There was no significant difference between self-reported and objective measures in the strength of associations with glucose regulation; associations with self-report were maintained when further adjusted for pedometer steps. Stronger associations between self-reported walking activity and glucose regulation were observed in South Asians compared with White Europeans. Self-reported and objectively measured walking activity were equally associated with indices of glucose regulation. Associations with self-reported walking activity were maintained when further adjusted for pedometer steps, suggesting that self-reported walking activity may measure facets of physical activity that are beyond total volume.