Jeffrey David Roizen MD PhD, FAAP

PubMed

• Letter to the editor regarding Duan et al, "CYP4A22 loss-of-function causes a new type of vitamin D-dependent rickets (VDDR1C)".
  Michael A Levine, Dong Li, Jeffrey Roizen, David Weber
  Journal of Bone and Mineral Research. 2025-03-15
• 1 citations
  High dose dietary vitamin D allocates surplus calories to muscle and growth instead of fat via modulation of myostatin and leptin signaling.
  Jeffrey Roizen, Caela Long, Alex Casella, Michael Nguyen, Lo Danahy
  Research Square. 2024-05-08
• Dietary vitamin D is a novel modulator of tumor engraftment through regulation of GC protein abundance.
  Lo Danahy, Caela Long, Ted J Hofmann, Zahra Tara, Julian Mark
  Research Square. 2024-02-16

Journal Articles

• Obesity Decreases Hepatic 25‐Hydroxylase Activity Causing Low Serum 25‐Hydroxyvitamin D  
  Michael A Levine, Jeffrey D Roizen, Journal of Bone and Mineral Research
• Decreased Serum 25-Hydroxyvitamin D in Aging Male Mice Is Associated with Reduced Hepatic Cyp2r1 Abundance  
  Jeffrey D Roizen, Michael A Levine, Endocrinology
• Progress in understanding type 1 diabetes through its genetic overlap with other autoimmune diseases  
  Roizen JD, Bradfield JB, Hakonarson H, Current Diabetes Reports, 1/1/2015

Books/Book Chapters

• The Parathyroids 
  Chapter: Chapter 25, Primary Hyperparathyroidism in Children and Adolescents. 
  Page 389 - 399Roizen J, Levine MAElsevierEdition 3rd,2014
• 5-Minute Pediatric Consult. 
  Chapter: Growth Hormone Deficiency 
  Page 378 - 379Roizen JD, Alter CEditors: Schwartz MW.Lippincott Williams and WilkinsEdition 6th,2012
• 5-Minute Pediatric Consult. 
  Chapter: Panhypopitutarism 
  Page 620 - 621Roizen JD, Alter CEditors: Schwartz MW.Lippincott Williams and WilkinsEdition 6th,2012

Abstracts/Posters

• Common polymorphism in Vitamin D 25-hydroxylase gene (CYP2R1) abrogates promoter activity.
  Roizen JD, Casella A, Levine M, J Bone Miner Res; ASBMR, 1/1/2015
• Resting Energy Expenditure (REE) is Decreased in Pseudohypoparathyroidism Type 1A
  Roizen JD, Danzig J, Groleau V, Bhoj E, Mulchandani S, Casella A, Harrington J, Sochett E, Tershekovec A, Zemel B, Stallings V, Levine, M, University of Pennsylvania IDOM Annual Meeting, 1/1/2015
• Decreasing CYP2R1 activity with aging is responsible for decreased calcidiol response to calciferol supplementation with age.
  Roizen JD, Casella A, Levine M, Endocrine Reviews; ENDO Society, 1/1/2014

Lectures

• Vitamin D in Children and Hyper and Hypocalcemia in Children 
  Lancaster, PA - 1/8/2015
• Hypoparathyroidism, Pseudohypoparathyroidism and APS1 
  Sacramento, CA - 1/6/2014
• Exenetide (Byetta) Prevents Obesity in Mouse Model of Hypothalamic Obesity. 
  1/1/2014

Other

• Metformin alters cardiometabolic fitness and may alter propensity to exercise. 
  Roizen JD, Pediatrics Online
  http://pediatrics.aappublications.org/content/131/3/e850.full/reply#pediatrics_el_55451
  1/25/2013
• Letter in Response to The Numbers Behind the Transit Strike 
  Roizen JD, The Wall Street Journal Online
  http://www.wsj.com/articles/SB113631113499836645
  New York, NY - 1/6/2006