Objective Physical activity is related to clinical outcomes, even after adjusting for body mass, but is rarely assessed in randomized clinical trials.
Research design and methods We conducted an observational analysis of data from the Nateglinide and Valsartan in Impaired Glucose Tolerance Outcomes Research trial, in which a total of 9306 people from 40 countries with impaired glucose tolerance and either cardiovascular disease or cardiovascular risk factors were randomized to receive nateglinide or placebo, in a 2-by-2 factorial design with valsartan or placebo. All were asked to also participate in a detailed lifestyle modification programme and followed-up for a median of 6.4 years with progression to diabetes as a co-primary end point. Seven-day ambulatory activity was assessed at baseline using research-grade pedometers. We assessed whether the baseline amount of physical activity was related to subsequent development of diabetes in individuals with impaired glucose tolerance.
Results Pedometer data were obtained on 7118 participants and 35.0% developed diabetes. In an unadjusted analysis each 2000-step increment in the average number of daily steps, up to 10 000, was associated with a 5.5% lower risk of progression to diabetes (HR 0.95, 95%CI 0.92 to 0.97), with >6% relative risk reduction after adjustment.
Conclusions Physical activity should be measured objectively in pharmacologic trials as it is a significant but underappreciated contributor to diabetes outcomes. It should be a regular part of clinical practice as well.
- diabetes mellitus
- exercise, physical activity
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Contributors WEK wrote the manuscript and researched the data. TY, JT, J-LS, LT, JJVM, MAB, SMH, and RRH reviewed the manuscript critically and contributed to the content. J-LS and LT performed the statistical analysis.
Funding The NAVIGATOR study was supported by Novartis, Inc. TY is supported by the NIHR Diet, Lifestyle and Physical Activity Biomedical Research Unit, Leicester, UK. WEK was supported by NIDDK/NIA grant DK081559 for purposes of this project.
Competing interests TY: Research support from the National Institute for Health Research (NIHR) Leicester Biomedical Research Centre and the NIHR Collaboration for Leadership in Applied Health Research and Care, East Midlands. MAB: Research support from Merck Serono; attended advisory boards with Boehringer Ingelheim, AstraZeneca, and Novo Nordisk. Her department has received research funding from Merck, Amylin, Lilly, and BMS. RRH: Research support from Amylin, Bayer, Merck, and Novartis; attended advisory boards with Amylin, Lilly, Merck, Novartis, and Novo Nordisk; and given lectures supported by Bayer, Lilly, Merck, and Novo Nordisk.
Patient consent Not required.
Ethics approval Duke University.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement The data contained in this manuscript are held at the Duke Clinical Research Institute.
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