Relationship between hemoglobin and grip strength in older adults: the ActiFE study

Although anemia is associated with low muscle strength, hemoglobin has been rarely studied considering ferritin.

To analyze the association between hemoglobin and grip strength in community-dwelling older adults.

We used data from a German cohort of adults ≥ 65 years, excluding those with CRP > 10 mg/L or taking iron supplements. Grip strength (kg) was measured using a Jamar dynamometer. Analysis was performed using multiple linear regression, adjusted for established confounders. Due to interaction, age-stratified (< 80, 80 +), further sex-stratified analysis in those < 80 years old and ferritin-stratified in men < 80 years were performed.

In total, 1294 participants were included in this analysis (mean age 75.5 years, 549 (42.3%) women, 910 (70.3%) < 80 years). On average, hemoglobin and grip strength were 14.9 g/dL and 41.3 kg for men, 13.9 g/dL and 25.1 kg for women. Hemoglobin was significantly positively associated with grip strength only among women < 80 years (β 0.923 [95% CI 0.196, 1.650]). For men < 80 years, the association was significant when ferritin was ≥ 300 µg/L (β 2.028 [95% CI 0.910, 3.146]). No association was detected among those participants 80 + .

Our data show an association between hemoglobin and grip strength only in women < 80 years old. For men < 80 years, the association was only significant with ferritin levels ≥ 300 µg/L. Considering the decreasing levels of hemoglobin and grip strength and the high prevalence of iron deficiency in older adults further analyses investigating this relationship with more iron specific parameters such as transferrin saturation are warranted.