Article on Walking and Diabetes Omitted Some Relevant Studies—Reply

In reply

We thank Batty and Shipley for highlighting some additional articles relevant to the association between physical activity and mortality among persons with diabetes. In our summary of the key studies, we purposely did not include those by Ford and DeStefano¹ and Saito et al² because they only briefly reported physical activity as one of many risk factors; they either used a single crude measure of physical activity¹ or did not examine physical activity in their main multivariate analyses.² We did not include the article by Kohl et al² because it did not measure physical activity but rather cardiorespiratory fitness, which we consider to be an important but different risk factor. As such, we did not consider these studies to be independent examinations of the impact of physical activity on disease incidence and mortality. We appreciate Batty and Shipley pointing out their own study⁴ as well as a study published this year from the Health Professional's Follow-up Study,⁵ which also examine the impact of physical activity and found results consistent with our own. Regrettably, these studies were published after our article was in press⁵ or under final review⁴ and thus were not included.