Commuting distance and its association with cardiorespiratory fitness and metabolic risk

Background: Sitting may have effects on metabolic risk independent from physical activity (PA). No known evidence exists on the metabolic risk correlates of prolonged sitting in motor vehicles. Objective: To examine the association between commuting distance, cardiorespiratory fitness (CRF) and metabolic risk. Methods: This cross-sectional analysis included 3,929 adults, mostly white and well educated, aged 18-90 years who had a comprehensive medical examination between 2000-2007 and with geocoded home and work addresses in 12 Texas metropolitan counties. ~95% of workers in this region commute by automobile. The primary exposure variable was commuting distance along the road network. Outcome variables included meeting public health PA recommendations (≥150 weekly minutes of self-reported PA), high CRF (≥ 60th percentile for age-sex distribution from a maximal treadmill test), obesity (BMI>30 kg/m2), and metabolic risk variables using the International Diabetes Federation criteria (high waist circumference (WC), raised fasting triglycerides, raised plasma glucose, reduced HDL cholesterol, raised blood pressure (BP), and metabolic syndrome (MS)). Logistic regression models were adjusted for socio-demographics, smoking status, alcohol intake, family history of diabetes, BMI, and history of high cholesterol (for blood lipids models). Results: Commuting >15 versus ≤5 miles was negatively associated (p<0.05) with meeting PA recommendations (adjusted OR[aOR]=0.72) and high CRF (aOR=0.80), and positively associated with obesity (aOR=1.5), high WC (aOR=1.4), raised BP (aOR=1.3), and MS (aOR=1.3). Associations with obesity and BP remained after adjustment for CRF. Conclusions: Commuting long distances may adversely affect health. Future research in more diverse populations is needed.