Total mortality by transferrin saturation levels: two general population studies and a metaanalysis

TY - JOUR

T1 - Total mortality by transferrin saturation levels: two general population studies and a metaanalysis

AU - Ellervik, Christina

AU - Tybjærg-Hansen, Anne

AU - Nordestgaard, Børge G

AU - Ellervik, Christina

AU - Tybjærg-Hansen, Anne

AU - Nordestgaard, Børge G

PY - 2011/3

Y1 - 2011/3

N2 - BACKGROUND: There is evidence for increased mortality in patients with clinically overt hereditary hemochromatosis. Whether increased transferrin saturation (TS), as a proxy for iron overload is associated with increased mortality in the general population is largely unknown. METHODS: We examined mortality according to baseline TS in 2 Danish population-based follow-up studies (the Copenhagen General Population Study and the Copenhagen City Heart Study) comprising a total of 45 159 individuals, of whom 4568 died during up to 18 years of follow-up, and in a metaanalysis comprising the present studies and an additional general population study. RESULTS: In combined studies, the cumulative survival was reduced in individuals with TS ≥50% vs <50% (log-rank P < 0.0001). Multifactorially adjusted hazard ratios for total mortality for TS ≥50% vs <50% were 1.4 (95% CI 1.2-1.6; P < 0.001) overall, 1.3 (1.1-1.6; P = 0.003) in men, and 1.5 (1.1-2.0; P = 0.005) in women. Results were similar if the 2 studies were considered separately. A stepwise increased risk of total mortality was observed for stepwise increasing levels of TS (log-rank P < 0.0001), with the highest risk conferred by TS ≥80% vs TS <20% with a hazard ratio of 2.2 (1.4-3.3; P < 0.001). The population-attributable risk for total mortality in the combined studies in individuals with TS ≥50% vs <50% was 0.8%. In metaanalysis, the odds ratio for total mortality for TS ≥50% vs <50% was 1.3 (1.2-1.5; P < 0.001) under the fixed-effects model. CONCLUSIONS: Individuals in the general population with TS ≥50% vs <50% have an increased risk of premature death.

AB - BACKGROUND: There is evidence for increased mortality in patients with clinically overt hereditary hemochromatosis. Whether increased transferrin saturation (TS), as a proxy for iron overload is associated with increased mortality in the general population is largely unknown. METHODS: We examined mortality according to baseline TS in 2 Danish population-based follow-up studies (the Copenhagen General Population Study and the Copenhagen City Heart Study) comprising a total of 45 159 individuals, of whom 4568 died during up to 18 years of follow-up, and in a metaanalysis comprising the present studies and an additional general population study. RESULTS: In combined studies, the cumulative survival was reduced in individuals with TS ≥50% vs <50% (log-rank P < 0.0001). Multifactorially adjusted hazard ratios for total mortality for TS ≥50% vs <50% were 1.4 (95% CI 1.2-1.6; P < 0.001) overall, 1.3 (1.1-1.6; P = 0.003) in men, and 1.5 (1.1-2.0; P = 0.005) in women. Results were similar if the 2 studies were considered separately. A stepwise increased risk of total mortality was observed for stepwise increasing levels of TS (log-rank P < 0.0001), with the highest risk conferred by TS ≥80% vs TS <20% with a hazard ratio of 2.2 (1.4-3.3; P < 0.001). The population-attributable risk for total mortality in the combined studies in individuals with TS ≥50% vs <50% was 0.8%. In metaanalysis, the odds ratio for total mortality for TS ≥50% vs <50% was 1.3 (1.2-1.5; P < 0.001) under the fixed-effects model. CONCLUSIONS: Individuals in the general population with TS ≥50% vs <50% have an increased risk of premature death.

KW - Adult

KW - Aged

KW - Aged, 80 and over

KW - Denmark

KW - Female

KW - Follow-Up Studies

KW - Hemochromatosis

KW - Humans

KW - Iron Overload

KW - Male

KW - Middle Aged

KW - Multivariate Analysis

KW - Population Surveillance

KW - Transferrin

U2 - 10.1373/clinchem.2010.156802

DO - 10.1373/clinchem.2010.156802

M3 - Journal article

C2 - 21228252

SN - 0009-9147

VL - 57

SP - 459

EP - 466

JO - Clinical Chemistry

JF - Clinical Chemistry

IS - 3

ER -