Vitamin B12 deficiency. Prevalence among South Asians at a Toronto clinic.

OBJECTIVE: To estimate the prevalence of vitamin B12 deficiency in adult South Asian patients. DESIGN: Retrospective chart review. SETTING: Family practice clinic in Toronto, Ont. PARTICIPANTS: Records of 988 South Asian patients. INTERVENTION: Of 1000 randomly selected records, we found 988 charts. From charts with at least one documented B12 level, we extracted data on age, mean corpuscular volume (MCV), hemoglobin and ferritin levels, and diet (if available). Descriptive and analytic statistics were calculated. MAIN OUTCOME MEASURES: Levels of serum B12 and factors associated with low levels of B12. RESULTS: B12 results were documented in 49% of charts; 46% of results showed deficiency. Patients older than 65 and vegetarians were more likely to be B12 deficient. Low serum B12 levels were positively correlated with low hemoglobin and ferritin levels and poorly correlated with low MCV levels. CONCLUSION: Many more South Asian patients than patients in the general population have vitamin B12 deficiency. A vegetarian diet seems a strong risk factor. A single low result, however, might not indicate true B12 deficiency.