Association Between Diabetes and Anemia: Evidence From NHANES and the UK Biobank

OBJECTIVE: To explore the association between diabetes and anemia. RESEARCH DESIGN AND METHODS: We included 9,026 and 389,616 participants from the U.S. National Health and Nutrition Examination Surveys and the UK Biobank study (UKB), respectively. Multivariable logistic regression was used to examine the cross-sectional association of diabetes with anemia, as defined by hemoglobin measurement. For the UKB follow-up, multivariable Cox proportional hazards regression was performed to estimate hazard ratios (HRs) and 95% CIs of incident anemia, as defined by hemoglobin levels or diagnosis records, in relation to diabetes. We further assessed the impact of inflammation, renal dysfunction, and medication use on this association in both populations. RESULTS: Among White people aged 40-69 years in the U.S. and U.K., the adjusted odds of study participants with diagnosed diabetes also having anemia was two to four times higher than in those with normal glycemia. Over a median follow-up of 13.6 years in the UKB, 42,354 people developed anemia. The adjusted HRs for incident anemia comparing diagnosed diabetes with normal glycemia were 3.05 (95% CI 2.90-3.21) for iron deficiency anemia, 3.02 (95% CI 2.51-3.63) for anemia of chronic disease, and 4.88 (95% CI 4.23-5.63) for vitamin B12 deficiency anemia. Further adjustment for inflammation, renal dysfunction, and medication use partially attenuated these associations, but they remained strong and significant. CONCLUSIONS: Diabetes was associated with several major types of anemia. Further studies are warranted to identify the mechanisms.