Impact of mercury exposure on blood pressure and cardiac autonomic activity among Cree adults (James Bay, Quebec, Canada).

Aboriginal populations from Quebec (Canada) are exposed to higher mercury levels than southern regions since these populations consume high quantities of fish. Epidemiological evidence suggests a detrimental impact of mercury on cardiovascular risk factors such as heart rate variability (HRV) and blood pressure (BP). The objective of this study was to assess the impact of mercury exposure on BP, resting heart rate (HR) and HRV among Cree adults. Data were collected among 791 adults≥18 years old living in seven communities of the James Bay. Blood mercury and hair levels were used as biomarkers of recent and long-term exposure. BP was measured through a standardised protocol while HRV was derived from a 2-h Holter monitoring assessment. The relationship between mercury and the outcomes was studied using ANOVA and ANCOVA analysis. Geometric mean of blood mercury and hair mercury concentration was 17.0 nmol/L (95%CI: 6.1-44.0) and 2.36 nmol/g (95%CI: 2.09-2.65); respectively. After adjusting for confounders, blood mercury was associated with HRV parameters such as LF (ß=0.21, P=0.0002), HF (ß=0.15, P=0.004) and LF/HF (ß=0.06, P=0.003). Similar associations were observed with hair mercury. In contrast, no significant association was observed between blood mercury or hair mercury and BP after adjusting for confounders. In conclusion, mercury exposure seems to affect HRV among Cree adults even after considering fish nutrients (n-3 fatty acids and selenium) and other contaminants (lead and polychlorinated biphenyls) that are also present in the traditional diet of this population.

Epidemiology of urinary infections in renal transplant recipients.

Urinary tract infection (UTI) remains a significant cause of infectious complications in renal transplant recipients. We evaluated prospectively all the UTIs in 161 kidney recipients transplanted between July 2003 and July 2005. All patients received prophylaxis with sulfadoxine-pyrimethamine. We excluded asymptomatic bacteriuria. Forty-one patients (25%) suffered at least one UTI episode. Ninety-two episodes of infection were confirmed with an incidence rate of 97 UTI episodes per 100 patient-years. The most common clinical features were uncomplicated acute bacterial cystitis, 71 episodes (77%), and acute pyelonephritis, 21 episodes (23%). Microbiological isolation was confirmed in 58 episodes (63%). Bacterial infections were the most frequent etiologies: gram-negative bacilli in 52 (90%), gram-positive cocci in 4 (7%), fungal in 2 (3%), and one viral BK virus (2%) infection. The causative microorganisms were E. coli as the principal isolated agent in 41 cases (71%), including 10 (24%) that were extended-spectrum betalactamases (ESBLEC). All episodes showed a favorable course. The survival rate of the graft at the end of the study period was 90.7%, and the survival rate of the transplant recipients was 97.5%. The incidence of UTI in transplant patients who received antibiotic prophylaxis was high. E. coli (ESBLEC) was the main agent isolated. Uncomplicated UTI, the most frequent post transplantation infection, showed a good prognosis.