Funding for this research was provided by:
National Institute of Diabetes and Digestive and Kidney Diseases (R01 DK031036, R01 DK056626, R37 DK048873, K12 HD000850, R01 DK033201, R01 DK103046)
Received: 13 January 2016
Accepted: 21 January 2016
First Online: 8 February 2016
Compliance with ethical standards
: The authors declare that they have no conflict of interest to report.