Prevalence and Correlates of Dietary Supplement Use in Individuals With Diabetes Mellitus at an Academic Diabetes Care Clinic

Abstract

Objectives This study sought to describe the prevalence of supplement use by those with diabetes mellitus receiving care at an academic outpatient diabetes care center and to identify any association of supplement use with glycemic control. Methods This study is based on a retrospective audit of provider-verified and patient–self-reported medication and supplement use by adults with diabetes at the University of Washington Diabetes Care Center during four 2-week periods from fall 2006 through summer 2007 (1 period per season). Results Verified medication and supplement histories for 459 adults demonstrated a per-person average use of 7 ± 4.1 prescription medicines and 0.4 ± 0.9 over-the-counter medicines daily, with 55% using some form of vitamin, mineral, or nonvitamin–nonmineral supplement on a daily basis. The rate of nonvitamin–nonmineral use was nearly twice that for type 2 diabetes mellitus as for type 1 diabetes mellitus (39.3% vs 20.3%), and A1c was lower in those using any supplement compared to those not using supplements. Vitamin use was associated with reduced A1c; however, this relationship did not hold at A1c < 7.0%. Conclusions The findings highlight the prevalence of supplement use in diabetes mellitus and association of supplement use with improved glycemic control. Findings are limited by the retrospective design.