Abstract
BackgroundThe vitamin B12 and folate status in nonanaemic healthy older persons needs attention the more so as decrease in levels may be anticipated from reduced haematinic provision and/or impaired intestinal uptake.MethodsA total of 1143 subjectively healthy Swiss midlands participants (637 females and 506 males), ≥60 years of age were included in this study. Levels of vitamin B12, holotranscobalamin (holoTC), methylmalonic acid (MMA), homocysteine (Hcy), serum folate, red blood cell (RBC) folate were measured. Further, Fedosov’s wellness score was determined. Associations of age, gender, and cystatin C/creatinine-based estimated kidney function, with the investigated parameters were assessed. Reference intervals were calculated. Further, ROC analysis was done to assess accuracy of the individual parameters in recognizing a deficient vitamin B12 status. Finally, decision limits for sensitive, specific and optimal recognition of vitamin B12 status with individual parameters were derived.ResultsThree age groups: 60–69, 70–79 and ≥ 80 had median B12 (pmol/L) levels of 237, 228 and 231 respectively (p = 0.22), holoTC (pmol/L) of 52, 546 and 52 (p = 0.60) but Hcy (μmol/L) 12, 15 and 16 (p < 0.001), MMA (nmol/L) 207, 221 and 244 (p < 0.001). Hcy and MMA (both p < 0.001), but not holoTC (p = 0.12) and vitamin B12 (p = 0.44) were found to be affected by kidney function. In a linear regression model Fedosov’s wellness score was independently associated with kidney function (p < 0.001) but not with age. Total serum folate and red blood cell (RBC) folate drift apart with increasing age: whereas the former decreases (p = 0.01) RBC folate remains in the same bandwidth across all age groups (p = 0.12) A common reference interval combining age and gender strata can be obtained for vitamin B12 and holoTC, whereas a more differentiated approach seems warranted for serum folate and RBC folate.ConclusionWhereas the vitamin B12 and holoTC levels remain steady after 60 years of age, we observed a significant increment in MMA levels accompanied by increments in Hcy; this is better explained by age-related reduced kidney function than by vitamin B12 insufficiency. Total serum folate levels but not RBC folate levels decreased with progressing age.Electronic supplementary materialThe online version of this article (doi:10.1186/s12877-015-0060-x) contains supplementary material, which is available to authorized users.
Highlights
The vitamin B12 and folate status in nonanaemic healthy older persons needs attention the more so as decrease in levels may be anticipated from reduced haematinic provision and/or impaired intestinal uptake
Reference intervals for total B12, holoTC, folate and red blood cell (RBC) folate were calculated by means of the non-parametric method, as recommended by the CLSI guideline C28-A3c [38, 39]
Our study on subjectively healthy elderly Caucasian participants from a circumscribed geographical region shows for the first time that holoTC, and vitamin B12 levels from 60 year onwards remain within Reference intervals (RI) set by international expert panels with people from all ages [42, 43] whereas serum folate concentrations – though not RBC folate - recede to some extent
Summary
The vitamin B12 and folate status in nonanaemic healthy older persons needs attention the more so as decrease in levels may be anticipated from reduced haematinic provision and/or impaired intestinal uptake. The clinical significance of water soluble vitamin B12 (cobalamin) and of folate, and the importance of their routine analysis, is supported by recent findings in physiology regarding their function [1,2,3,4,5,6,7,8]. The simple yet biologically important role of support by these vitamins in catalysis of methyl group transfer is essential for life maintenance [9]. The function of folate overlaps with vitamin B12 both of them being essential in methylation reactions. Vitamin B12 deficiency later in life is estimated to affect 10 % of people over the age of 60 [11, 12]. Optional but frequently practiced fortification of grain-based food supply is done with folic acid and vitamin B12 (www.blv.admin.ch)
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