OBJECTIVE: To measure the prevalence of low serum vitamin B12, folate, and red cell folate levels and their relationship with other nutritional indices. DESIGN: Prospective survey of elderly subjects using radioisotope dilution assays. SETTING: Primary care medical center, Christchurch, New Zealand. PATIENTS: 257 elderly subjects (age 65 years and over), residing in their own homes or in residential homes, were randomly selected. Of these, 204 (79%) participated. The study population was comparable to the elderly population of New Zealand. MAIN OUTCOME MEASURES: Vitamin B12, serum, and red cell folate levels. RESULTS: The prevalence rates for low levels of serum vitamin B12, folate, and red cell folate were 7.3%, 1%, and 3.3%, respectively. The elderly cohort had lower vitamin B12 (P less than 0.001) but higher serum and red cell folate levels (P less than 0.001) than our normal reference range (age 18-65 years). Red blood cell folate levels showed positive correlations with nutritional indices and mental test scores. No correlations were found between vitamin B12 levels and diet or other nutritional indices. CONCLUSIONS: Low folate levels in older people living at home are infrequent findings. In contrast low vitamin B12 levels are more common. Poor diet and undernutrition may contribute to low folate levels, but these factors are less important for the low B12 levels found.
OBJECTIVE: To measure the prevalence of low serum vitamin B12, folate, and red cell folate levels and their relationship with other nutritional indices. DESIGN: Prospective survey of elderly subjects using radioisotope dilution assays. SETTING: Primary care medical center, Christchurch, New Zealand. PATIENTS: 257 elderly subjects (age 65 years and over), residing in their own homes or in residential homes, were randomly selected. Of these, 204 (79%) participated. The study population was comparable to the elderly population of New Zealand. MAIN OUTCOME MEASURES: Vitamin B12, serum, and red cell folate levels. RESULTS: The prevalence rates for low levels of serum vitamin B12, folate, and red cell folate were 7.3%, 1%, and 3.3%, respectively. The elderly cohort had lower vitamin B12 (P less than 0.001) but higher serum and red cell folate levels (P less than 0.001) than our normal reference range (age 18-65 years). Red blood cell folate levels showed positive correlations with nutritional indices and mental test scores. No correlations were found between vitamin B12 levels and diet or other nutritional indices. CONCLUSIONS: Low folate levels in older people living at home are infrequent findings. In contrast low vitamin B12 levels are more common. Poor diet and undernutrition may contribute to low folate levels, but these factors are less important for the low B12 levels found.