Is thiamine deficiency in elderly people related to age or co-morbidity?

OBJECTIVES to compare erythrocyte thiamine pyrophosphate concentrations in elderly people with those in healthy younger people; to determine if any differences can be attributed to age or to co-morbidities. DESIGN cross-sectional and 3-year longitudinal surveys. SETTING primary care. PATIENTS 100 volunteer blood donors and 222 elderly people from a general practice register. MEASUREMENTS thiamine pyrophosphate concentrations using high performance liquid chromatography; physical examination, medical and medication history; grip strength, body mass index and plasma albumin. RESULTS the mean [95% confidence interval (CI)] thiamine pyrophosphate concentration was 152 nmol/l (147-158) in the elderly group and 224 (213-235) nmol/l in the younger group (P < 0.001). Ninety-six (43.4%) of the elderly subjects had thiamine pyrophosphate concentrations below the fifth percentile of the younger subjects (140 nmol/l). Over 3 years thiamine pyrophosphate concentrations fell in the elderly cohort by 20% (95% CI: 14.5-24.5%; P < 0.01). Thiamine pyrophosphate concentrations in 39 healthy older people were no different from those in elderly people with co-morbidity but were significantly lower than those in the younger people. Elderly people with absent vibration sense in their feet had a lower thiamine pyrophosphate concentration than the rest of the group [129 (117-142)nmol/l compared with 156 (150-162)nmol/l; P < 0.01)]. Thiamine pyrophosphate concentrations were not related to prevalent diseases, common medications, body mass index, grip strength or plasma albumin. CONCLUSION lower thiamine pyrophosphate concentrations in elderly people appear to be related more to age itself than to co-existent illnesses.