Physical inactivity and non-communicable disease burden in low-income, middle-income and high-income countries.

"Competing interests: All authors have completed the ICMJE uniform disclosure form and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work."

"Funding and Role of the Funding Source This work was supported, in part, by the National Institute of General Medicine Sciences of the National Institutes of Health under Award Number U54-GM104940, the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health under Award Number P30-DK072476, and by the Intramural Research Program at the National Institute on Aging (US). The funding sources had no role in the writing of the manuscript or the decision to submit it for publication. The corresponding author had full access to all the data and had final responsibility for the decision to submit for publication."