Résumé
Supraphysiological levels (SFL) of serum folate (SF) derived from flour fortification with folic acid (FA) could be risky among older adults with low vitamin B12 (B12) levels. Aim: To describe and analyze SF and B12 levels in older Chileans and to identify risk groups. Material and Methods: Participants were 1.043 older people aged ≥ 65 years from the National Health Chilean Health Survey 2009-2010 (ChNHS 2009-10), a multistage stratified random sample, representative of the national population. SF (µg/L) and B12 (pg/ml) were determined in fasting samples by competitive chemoluminescence immunoassay. Mean, deciles and percentiles 5 and 95th were calculated. We defined SF categories: < 4.4 (deficit); 4.41-20 (normal) and SFL: 20.01-25.6; 25.6-29 and > 29 µg/L (80th percentile of the distribution) and vitamin B12 categories: ≤ 200 (deficit); 200.1-299.5 (marginal deficit) and > 299.5 (normal). Prevalence rates, multiple and logistic regression models were used and adjusted by sex and age, educational level and residence area. Results: SF and B12 mean and 95th percentiles were 21.2 ± 0.56/38.6 µg/L and 348.4 ± 7.6/637(pg/ml) respectively. Forty nine percent of participants had SFL. Folate and B12 deficiency were present in 0.3 and 8.1% of participants, respectively. Men had significantly lower prevalence of SFL > 29 µg/L (OR adjusted odds ratio 0.47 95% confidence intervals: 0.26-0.84). B12 showed no significant variation by age and sex. The prevalence of SFL associated with B12 deficiency was 4.1%. No statistically significant association was observed between levels of folate and B12. Conclusions: Folate deficit is almost inexistent, but a significant percentage of participants had SFL suggesting the need for revising the current wheat flour fortification levels.