Influence of Age on Serum Cobalamin and Folate Concentrations in Healthy Cats
The prevalence of both cobalamin and folate deficiency increases with increasing age in humans, and these deficiencies have been associated with vascular disease and neurocognitive disorders. In the United States, the average age of the pet cat population has increased over the past decade. In the cat, alterations in intestinal tract physiology develop with increasing age. These changes result in decreased digestive efficiency, which could culminate in deficiencies of either cobalamin and/or folate. Therefore, the purpose of this study was to evaluate a possible effect of age on serum cobalamin and folate concentrations in the healthy cats. It was hypothesized that serum cobalamin and folate concentrations would decrease with increasing age.
Eighty-eight healthy cats were recruited and placed into one of four groups based on age-life stage: Group 1: less than one year, Group 2: 1 to <8 years, Group 3: 8 to <13 years, and Group 4: > 13 years. Serum cobalamin (reference range: 290-1,500 ng/L) and folate concentrations (reference range: 9.7-21.6 µg/L) samples were measured in samples which were obtained after a twelve hour fast.
Overall, two cats (2.3%) had subnormal cobalamin concentrations and 8 cats (9.1%) had subnormal folate concentrations. For Group 1 (n=21), the median serum cobalamin concentration was 1,113 ng/L (range: 267-4,143 ng/L) and the median folate concentration was 19.9µg/L (range: 9.6-39.8 µg/L). Cats of Group 2 (n=21) had a median cobalamin concentration of 1,524 ng/L (range: 197-4,282 ng/L) and a median folate concentration of 15.3 µg/L (range: 6.7-26 µg/L). The median cobalamin concentration for Group 3 (n=23) was 953 ng/L (range: 494-2,333 ng/L) and median folate concentration was 12.8 µg/L (range: 7.2-23.5 µg/L). For Group 4 (n=23), the median cobalamin concentration was 811 ng/L (range: 293-3,136 ng/L) and the median folate concentration was 14.4 µg/L (range: 6.7-35.9). Both the median serum cobalamin and folate concentrations were significantly different between age groups (p=0.008 and p=0.025, respectively). For cobalamin concentrations, the greatest difference was between Groups 2 and 4 (p= 0.004). Serum cobalamin concentration was inversely correlated with age (Spearman r= -0.353; p<0.001). Serum folate concentration was more weakly inversely correlated with age (Spearman r= -0.243; p=0.023). The median serum cobalamin concentration in cats 8 years and older (870.5 ng/L) was significantly lower than that of cats under the age of 8 (1,274 ng/L) (p=0.002).
While some cats in this healthy population were identified as having subnormal cobalamin or folate concentrations, the majority were not. However, this study suggests that, as cats age, their serum cobalamin and folate concentrations decrease significantly. Clinically this could be important as cats which are greater than eight years of age may be more likely to become deficient when affected by conditions that can alter cobalamin and folate homeostasis.