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.

Effectiveness of the Immigration Medical Surveillance Program for tuberculosis in Ontario.

BACKGROUND: Citizenship and Immigration Canada (CIC) screens immigrants for TB and permits those with inactive pulmonary TB to enter Canada conditionally, subject to medical surveillance; we studied this program in Ontario. METHOD: This was an administrative database study with linkage of national and provincial data. RESULTS: In 1994-95, 1,341 cases of foreign-born active TB were diagnosed and a CIC record was found for 1,095. 149 (14%) were classified for surveillance and 142 were included in the analysis. A significant proportion (39/142: 27%) were diagnosed either before or as a result of immigration screening in Canada. These persons had arrived as visitors or refugees and were excluded from further analysis. Only 21 of the remaining 103 persons (20%) with immigration screening before the diagnosis of TB adhered to surveillance. Only 1 of 16 (6%) eligible persons was given therapy to prevent future episodes of active TB. Most presented with symptoms (82/103:82%) suggesting potential for TB transmission in Ontario. INTERPRETATION: The current TB surveillance system for high-risk immigrants to Ontario is not effective in identifying and treating latent infection, and thus not effective in preventing future cases.