Higher incidence of childhood-onset type 1 diabetes mellitus in remote areas: a UK regional small-area analysis

Aims/hypothesis: We investigated the association between the incidence of type 1 diabetes mellitus and remoteness (a proxy measure for exposure to infections) using recently developed techniques for statistical analysis of small-area data.

Subjects, materials and methods: New cases in children aged 0 to 14 years in Northern Ireland were prospectively registered from 1989 to 2003. Ecological analysis was conducted using small geographical units (582 electoral wards) and area characteristics including remoteness, deprivation and child population density. Analysis was conducted using Poisson regression models and Bayesian
hierarchical models to allow for spatially correlated risks that were potentially caused by unmeasured explanatory variables.

Results: In Northern Ireland between 1989 and 2003, there were 1,433 new cases of type 1 diabetes, giving a directly standardised incidence rate of 24.7 per 100,000 personyears. Areas in the most remote fifth of all areas had a significantly (p=0.0006) higher incidence of type 1 diabetes mellitus (incidence rate ratio=1.27 [95% CI 1.07, 1.50]) than those in the most accessible fifth of all areas. There was also a higher incidence rate in areas that were less deprived (p<0.0001) and less densely populated (p=0.002). After adjustment for deprivation and additional adjustment for child population density the association between diabetes and remoteness remained significant (p=0.01 and p=0.03, respectively).

Conclusions/interpretation: In Northern Ireland, there is evidence that remote areas experience higher rates of type 1 diabetes mellitus. This could reflect a reduced or delayed exposure to infections, particularly early in life, in these areas.

Incidence of Fas positivity and deoxyribonucleic acid double-stranded breaks in human ejaculated sperm.

Objective

To determine the incidence of Fas positivity and DNA double-strand breaks (DSB) as indicators of early- and late-stage apoptosis in ejaculated sperm.

Design

Fas positivity was assessed by flow cytometry and DSB by the neutral Comet assay.

Setting

Andrology Laboratory, Royal Maternity Hospital, Belfast, Northern Ireland, United Kingdom.

Patient(s) and intervention(s)

Forty-five infertile men undergoing infertility investigations and 10 fertile men undergoing vasectomies.

Main outcome measure(s)

Percentage Fas-positive cells, percentage DNA fragmentation, olive tail moment.

Result(s)

The apoptotic marker Fas was detected in ejaculated sperm, with a higher incidence of Fas positivity in teratozoospermic and asthenozoospermic than in normozospermic semen. No Fas positivity was observed in fertile mens' sperm. Deoxyribonucleic acid fragmentation (DSB) was greater in infertile than in fertile men's sperm and also greater in sperm in semen than in sperm prepared for assisted conception. There was an inverse relationship between DSB and both sperm concentration and motility. There was no relationship between Fas positivity and DNA damage.

Conclusion(s)

Fas was expressed in sperm of infertile men. In contrast, DNA fragmentation was observed in all sperm of fertile and infertile men and correlated with inadequate concentration and motility, which suggests that sperm DSB are ubiquitous and are not solely associated with apoptosis.

Modelling the impact of antibiotic use and infection control practices on the incidence of hospital-acquired methicillin-resistant Staphylococcus aureus: a time-series analysis

Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen worldwide. A wide range of factors have been suggested to influence the spread of MRSA. The objective of this study was to evaluate the effect of antimicrobial drug use and infection control practices on nosocomial MRSA incidence in a 426-bed general teaching hospital in Northern Ireland.

Methods: The present research involved the retrospective collection of monthly data on the usage of antibiotics and on infection control practices within the hospital over a 5 year period (January 2000–December 2004). A multivariate ARIMA (time-series analysis) model was built to relate MRSA incidence with antibiotic use and infection control practices.

Results: Analysis of the 5 year data set showed that temporal variations in MRSA incidence followed temporal variations in the use of fluoroquinolones, third-generation cephalosporins, macrolides and amoxicillin/clavulanic acid (coefficients = 0.005, 0.03, 0.002 and 0.003, respectively, with various time lags). Temporal relationships were also observed between MRSA incidence and infection control practices, i.e. the number of patients actively screened for MRSA (coefficient = -0.007), the use of alcohol-impregnated wipes (coefficient = -0.0003) and the bulk orders of alcohol-based handrub (coefficients = -0.04 and -0.08), with increased infection control activity being associated with decreased MRSA incidence, and between MRSA incidence and the number of new patients admitted with MRSA (coefficient = 0.22). The model explained 78.4% of the variance in the monthly incidence of MRSA.

Conclusions: The results of this study confirm the value of infection control policies as well as suggest the usefulness of restricting the use of certain antimicrobial classes to control MRSA.