Physical activity, sitting, and risk factors of cardiovascular disease: a cross-sectional analysis of the CARRS study

We aimed to estimate the associations between substituting 30-min/day of walking or moderate-to-vigorous physical activity (MVPA) for 30min/day of sitting and cardiovascular risk factors in a South Asian population free of cardiovascular disease. We collected information regarding sitting and physical activity from a representative sample of 6991 participants aged 20years and above from New Delhi, India and Karachi, Pakistan enrolled in 2010-2011 in the Center for cArdio-metabolic Risk Reduction in South Asia study using the International Physical Activity Questionnaire (short form). We conducted isotemporal substitution analyses using multivariable linear regression models to examine the cross-sectional associations between substituting MVPA and walking for sitting with cardiovascular risk factors. Substituting 30min/day of MVPA for 30min/day of sitting was associated with 0.08mmHg lower diastolic blood pressure (=-0.08 [-0.15, -0.0003]) and 0.13mg/dl higher high-density lipoprotein cholesterol (=0.13 [0.04, 0.22]). Substituting 30min/day of walking for 30min/day of sitting was associated with 0.08kg/m(2) lower body mass index (=-0.08 [-0.15, -0.02]), and 0.25cm lower waist circumference (=-0.25 [-0.39, -0.11]). In conclusion, substituting time engaged in more-active pursuits for time engaged in less-active pursuits was associated with modest but favorable cardiovascular risk factor improvements among South Asians.