Expert opinion and clinical experience regarding patients with type 1 diabetes mellitus fasting on Yom Kippur.

This commentary constitutes the opinions of the endocrinologists whose names are appended. The commentary is based on articles published in peer-reviewed journals as listed in the cited references, as well as cumulative experience in treating patients with type 1 diabetes mellitus (T1DM). This commentary applies only to patients with T1DM, and does not apply to patients with type 2 DM who are being treated with insulin even though the principles may be similar. The recommendations outlined also do NOT apply to the pregnant woman with T1DM, who should not fast. Additionally, this commentary does not preclude an individual from directing any questions having to do with religious observance to a competent Rabbi. For example, with regard to fingerstick blood glucose testing, which requires the use of an electronic meter, we have received written council from Rabbi Yosef Shalom Eliashiv and Rabbi Joseph Efrati (Jerusalem, Israel), and Rabbi M. Weissmandl and Rabbi Mordechai Willig (NY) that the procedure is permissible when performed appropriately for the patient's welfare and health while fasting on Yom Kippur.