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The prevalence and associated mortality of non‐anaemic iron deficiency in older adults: a 14 years observational cohort study
Author(s) -
Philip Keir E. J.,
Sadaka Ahmed S.,
Polkey Michael I.,
Hopkinson Nicholas S.,
Steptoe Andrew,
Fancourt Daisy
Publication year - 2020
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/bjh.16409
Subject(s) - medicine , hazard ratio , confidence interval , proportional hazards model , demography , observational study , cohort study , ferritin , iron deficiency , anemia , sociology
Summary Iron is central to multiple biological pathways, and treatment of non‐anaemic absolute iron deficiency (NAID) is beneficial in certain conditions. However, it is unknown if NAID is associated with increased mortality in older adults. A nationally representative sample of 4451 older adults from the English Longitudinal Study of Ageing was used. NAID was defined as serum ferritin < 30 μg/l and haemoglobin ≥ 120 g/l (women) or ≥ 130 g/l (men). Cumulative mortality was estimated by Kaplan–Meier method. Unadjusted and adjusted hazard ratios (HRs) of mortality were calculated using Cox proportional hazards regression models. Baseline NAID prevalence was 8·8% (95% confidence interval [CI] 8·0–9·7%); 10·9% (95% CI 9·7–12·3%) for women and 6·35% for men (95% CI 5·3–7·5%). The HR for mortality for individuals with NAID compared with non‐anaemic individuals without iron deficiency over the 14‐year follow‐up was 1·58 (95% CI 1·29–1·93). This association was independent of all identified demographic, health‐related and biological covariates, and robust in multiple sensitivity analyses. In older adults in England, NAID is common and associated with an increased mortality rate compared to non‐anaemic individuals with normal serum ferritin. The association is principally driven by an excess mortality in women.