Low levels of vitamin B12 and venous thromboembolic disease in elderly men.

OBJECTIVES: Hyperhomocysteinaemia is a well-known risk factor for venous thromboembolic disease (VTD). However, it is not clear whether homocysteine (Hc) itself or a related metabolite or a cofactor is primarily responsible for VTD. We carried out a case-control study to investigate whether vitamin concentrations that are involved in the Hc metabolism are associated or not with an elevated risk of VTD. DESIGN: Case-control study. METHODS: We measured serum vitamin B12, folate, creatinine and albumin concentrations and plasma Hc concentrations in 101 consecutive patients with VTD, diagnosed by image tests and 101 control subjects, matched for age and sex. RESULTS: Serum vitamin B12 concentrations were significantly lower in VTD patients than in the control subjects. There were no differences in plasma Hc or serum folate concentrations between the groups. Among the male subgroup aged more than 70 years, serum vitamin B12 concentrations were significantly lower (240.88 +/- 103.07 vs. 421.20 +/- 314.31 pmol L(-1); P = 0.03) and plasma Hc concentrations were significantly higher (13.1 +/- 4.18 vs. 10.56 +/- 3.06 micromol L(-1); P =0.04) in VTD patients than in the control group. On multivariate analysis, in patients aged more than 70 years, serum vitamin B12 concentrations were independently associated with VTD. Compared with the highest quartile of vitamin B12 (>512.6 pmol L(-1)) the odds ratio (OR) for VTD in the lowest quartile (<230.9 pmol L(-1)) was 3.8 (95% CI 1.44-10.18; P = 0.01). In the VTD group, lowest vitamin B12 concentrations (percentile 10 <152.8 pmol L(-1)) were associated with the factor V Leiden mutation (OR = 6.07, 95% CI 0.93-38.55; P = 0.04). CONCLUSIONS: Measuring vitamin B12 concentrations in elderly males may help in identifying people at risk of venous thromboembolism in our population.

[Tularemia outbreak in the province of Cuenca associated with crab handling]. / Brote epidémico de tularemia en la provincia de Cuenca en relación con la manipulación de cangrejos.

OBJECTIVE: To report the clinical and epidemiologic characteristics of 19 patients diagnosed of tularemia at our hospital following an epidemic outbreak occurred in our health area. METHODS: Retrospective analysis of clinical records of patients admitted to our hospital who were examined at the Infectious Diseases Clinic and had clinical findings and epidemiologic data consistent with tularemia during the period from June 1998 to March 1999. CASE DEFINITION: A patient was considered to fulfill the case definition when clinical symptoms, epidemiologic data and the following laboratory criteria were met: antibody titer to Francisella tularensis (tube agglutination test) > or = 1/128 in the convalescence serum specimen, seroconversion or recovery of the microorganism from biological material. RESULTS: Nineteen patients with a median age of 60 years. Males predominated (63.1% male patients); all of them had handled red crayfish from the same source (río Mayor). The incubation period ranged from 0 to 15 days (mean 4.88 days). All patients presented with the ulceroglandular form. Seventy-three percent of patients received doxycycline. Only one patient relapsed. Water samples from the reservoir of the depuration plant of the river were positive to F. tularensis by PCR. This same result was confirmed in stomach and hepatopancreas of crayfish fished in río Mayor in the second half of July. CONCLUSIONS: The most likely hypothesis of this outbreak was the contamination of the river water with animals dead from tularemia which, together with the characteristics of the transmission mechanism (wounds caused by crabs) had contributed to the acquisition of this disease in humans. Interestingly too, red crayfish as the source of infection.