Investigation of a foodborne outbreak of Shigella sonnei in Ireland and Northern Ireland, December 2016: the benefits of cross-border collaboration and commercial sales data.

OBJECTIVES: To describe a cross-border foodborne outbreak of Shigella sonnei that occurred in Ireland and Northern Ireland (NI) in December 2016 whilst also highlighting the valuable roles of sales data and international collaboration in the investigation and control of this outbreak. STUDY DESIGN: A cross-border outbreak control team was established to investigate the outbreak. METHODS: Epidemiological, microbiological, and environmental investigations were undertaken. Traditional analytical epidemiological studies were not feasible in this investigation. The restaurant chain provided sales data, which allowed assessment of a possible increased risk of illness associated with exposure to a particular type of heated food product (product A). RESULTS: Confirmed cases demonstrated sole trimethoprim resistance: an atypical antibiogram for Shigella isolates in Ireland. Early communication and the sharing of information within the outbreak control team facilitated the early detection of the international dimension of this outbreak. A joint international alert using the European Centre for Disease Control's confidential Epidemic Intelligence Information System for Food- and Waterborne Diseases and Zoonoses (EPIS-FWD) did not reveal further cases outside of the island of Ireland. The outbreak investigation identified that nine of thirteen primary case individuals had consumed product A from one of multiple branches of a restaurant chain located throughout the island of Ireland. Product A was made specifically for this chain in a food production facility in NI. S. sonnei was not detected in food samples from the food production facility. Strong statistical associations were observed between visiting a branch of this restaurant chain between 5 and 9 December 2016 and eating product A and developing shigellosis. CONCLUSIONS: This outbreak investigation highlights the importance of international collaboration in the efficient identification of cross-border foodborne outbreaks and the value of using sales data as the analytical component of such studies.

Background prevalence of subclinical Shiga toxin-producing Escherichia coli in children attending childcare facilities in the Irish Midlands.

BACKGROUND: Exclusion of asymptomatic shedders of Shiga toxin-producing Escherichia coli (STEC) from childcare facilities (CCFs) is a recognized measure to minimize risk of secondary transmission. This is predicated on factors including an assumption of low background prevalence of STEC amongst CCF attendees. There is a paucity of scientific evidence regarding the true prevalence of STEC in paediatric populations. The study aimed to develop and test a methodology to estimate background prevalence of STEC amongst CCF attendees at regional level in Ireland. METHODS: Computerized Infectious Disease Reporting data were used to compile a list of outbreaks of STEC occurring in CCFs in the Irish Midlands since the introduction of polymerase chain reaction (PCR)-based testing. Laboratory data were used to determine background prevalence of STEC in screened children in each outbreak individually and across all outbreaks. RESULTS: A pooled summary prevalence estimate of 2.9% (95% confidence interval 1.4-5.5%) was determined for the entire screened cohort across all outbreaks. Sensitivity analysis supported the validity of the estimate. CONCLUSIONS: The relatively high prevalence estimate of 2.9% suggests that a public health risk assessment approach to return of prolonged asymptomatic shedders to the CCF may be appropriate in peak STEC season in the Midlands.

A 10-year analysis of VTEC microbiological clearance times, in the under-six population of the Midlands, Ireland.

Verotoxin-producing Escherichia coli (VTEC) is a significant problem in the under-six population in the Midlands, Ireland. VTEC spreads by person-to-person transmission and children attending childcare facilities are excluded until they achieve two consecutive negative stool samples. This report analyses 10 years data on the number of days children under the age of six take to microbiologically clear VTEC. We identified from our data that the median clearance time for VTEC was 39 days, interquartile range (IQR) 27-56 days, maximum clearance time 283 days. At 70 days from onset of infection, 90% of children had cleared the infection. These findings were slightly more prolonged but consistent with international literature on VTEC clearance times for children. Asymptomatic children cleared VTEC infection significantly faster (median time 25 days IQR 13-43 days) than symptomatic children (median time 43 days IQR 31-58 days). Symptomatic children older than 1 year of age cleared VTEC infection significantly faster (median time 42 days IQR 31-57) than symptomatic children year under 1 year (median time 56 days IQR 35-74 days). This report identifies clear data which can be used to more accurately advise parents on time periods required to achieve microbiological clearance from VTEC.

A geostatistical investigation of agricultural and infrastructural risk factors associated with primary verotoxigenic E. coli (VTEC) infection in the Republic of Ireland, 2008-2013.

Ireland reports the highest incidence of verotoxigenic Escherichia coli (VTEC) infection in Europe. This study investigated potential risk factors for confirmed sporadic and outbreak primary VTEC infections during 2008-2013. Overall, 989 VTEC infections including 521 serogroup O157 and 233 serogroup O26 were geo-referenced to 931 of 18 488 census enumeration areas. The geographical distribution of human population, livestock, unregulated groundwater sources, domestic wastewater treatment systems (DWWTS) and a deprivation index were examined relative to notification of VTEC events in 524 of 6242 rural areas. Multivariate modelling identified three spatially derived variables associated with VTEC notification: private well usage [odds ratio (OR) 6·896, P < 0·001], cattle density (OR 1·002, P < 0·001) and DWWTS density (OR 0·978, P = 0·002). Private well usage (OR 18·727, P < 0·001) and cattle density (OR 1·001, P = 0·007) were both associated with VTEC O157 infection, while DWWTS density (OR 0·987, P = 0·028) was significant within the VTEC O26 model. Findings indicate that VTEC infection in the Republic of Ireland is particularly associated with rural areas, which are associated with a ubiquity of pathogen sources (cattle) and pathways (unregulated groundwater supplies).

Relationship between parent held child records for immunisations, parental recall and health service.

Parent held child records (PHCR) were introduced in Ireland in 2008. This study investigated the relationship between the PHCR, parental recall and regional Health Service Executive (HSE) records for immunisation uptake. It used the Lifeways cohort study of 1070 singleton children to compare immunisation data from PHCR at one year, parental recall at five years and information from the HSE. When compared to HSE records, full recording of primary immunisations in the PHCR was reported for 695 of 749 (92.8%) children. Parental recall was correct for 520 of 538 (96.7%) children. Of the 307 completed PHCRs, 207 (75.9%) agreed with the HSE records. Agreement between the three sources for primary immunisations was 74-93% but was not statistically significant. Agreement was 91% (p < 0.001) for measles, mumps and rubella (MMR) vaccines between parental recall and HSE records. PHCRs underestimated and parental recall overestimated immunisation status when compared with HSE records.

Socio-demographic and health-related predictors of uptake of first MMR immunisation in the Lifeways Cohort Study.

The aim of this study was to investigate the uptake of the first dose of measles, mumps and rubella (MMR) vaccine and factors associated with not receiving this vaccine. A cross-generation cohort study was conducted with prospective linkage to primary care and hospital health records in urban and rural settings in Ireland 2001-2004. Seven hundred and forty-nine singleton children were included, with an MMR uptake of 88.7% by the age of 5 years. These data confirm prospectively for the first time that in addition to factors associated with disadvantage, other health practices and beliefs, particularly mother's complementary and alternative medicine use, are associated with decreased MMR uptake (adjusted OR 2.65 (1.76-3.98)). This information suggests that parental attitudes and beliefs regarding vaccines must be considered when developing programmes to improve immunisation uptake.

Determinants of partial or no primary immunisations.

OBJECTIVE: To determine if different factors affect children having full, partial or no primary immunisations. METHODS: This was a crossgenerational cohort study with linkage to primary care and hospital records conducted in urban and rural settings in Ireland, recruiting in 2001-2003 with 5-year follow-up. A total of 749 children with immunisation information took part. RESULTS: The uptake of reported primary immunisations was 92.8% full, 4.9% partial and 2.3% no primary immunisations. Adjusted relative risk ratios for children receiving no primary immunisations were significant for: having a mother who had ever visited an alternative practitioner 3.69 (1.05 to 12.9), a mother with means tested full general medical services eligibility 8.11 (1.58 to 41.65), a mother who scored <50 for the World Health Organization Quality of Life (WHO-QOL) scale psychological domain 8.82 (1.79 to 43.6) or living in the west of Ireland (rural) 3.64 (1.0 to 13.2). Being born prematurely was associated with partial primary immunisation, adjusted OR 4.63 (1.24 to 17.3). CONCLUSIONS: Knowledge of these differences will help target campaigns to increase full uptake of primary immunisations.

The Lifeways Cross-Generation Study: design, recruitment and data management considerations.

The Lifeways Cross-Generation Cohort Study was first established in 2001 and is a unique longitudinal database in Ireland, with currently over three and a half thousand family participants derived from 1124 mothers recruited initially during pregnancy, mainly during 2002. The database comprises a) baseline self-reported health data for all mothers, a third of fathers and at least one grandparent b) clinical hospital data at recruitment, c) three year follow-up data from the families' General Practitioners, and d) linkage to hospital and vaccination databases. Data collection for the five-year follow-up with parents is underway, continuing through 2007. Because there is at present no single national/regional health information system in Ireland, original data instruments were designed to capture data directly from family members and through their hospitals and healthcare providers. A system of relational databases was designed to coordinate data capture for a complex array of study instruments and to facilitate tracking of family members at different time points.

Dietary habits of pregnant women in Ireland.

This analysis of the Lifeways Cohort study mothers during pregnancy (n = 1124), utilises information from a standard food frequency questionnaire completed at baseline recruitment during early pregnancy. We demonstrate that 76% of women achieved recommended intakes of 5 plus portions of fruit and vegetables daily, though this is strongly socially patterned, inversely associated with age and positively associated with level of education. Achievement of the other recommended shelf intakes of the Food Pyramid is much lower, ranging from 12% achieving the recommended sparing intake of foods high in fat, salt or sugar, to 45% consuming the recommended 3 portions per day of meat and poultry. General medical services eligible respondents are generally less likely to achieve recommended intakes. While 61% of women under 25 years old stopped drinking during pregnancy, this dropped to 38% of expectant mothers over 35 years. Less than half (45%) of those (n = 860) who responded specifically to the question reported peri-conceptual folate supplement intake, again strongly socially patterned. These findings both provide important prevalence data and highlight the need for more concerted and supportive health promotion interventions during pregnancy.

The risk factor profile of grandparents.

In the Lifeways Cross Generation Cohort Study, mothers were asked to recruit at least one of 4 potential living grandparents to the study, and 1177 grandparents became active participants who either completed a health status questionnaire only (n = 707), or subsequently underwent a cardiovascular risk assessment examination at home (n = 958). Mean age of grandfathers at baseline was 61.5 years (SD 10.3), of grandmothers 59.2 years (SD 9.1), with a range of 40-83 years, 21% of grandmothers and 16% of grandfathers were third level educated. Risk factor profile of grandparents tended to be more adverse than the general population as assessed by the standard cardiovascular risk factor SCORE. Grandparents' socio-demographic characteristics were similar, whether maternal or paternal in origin. Predictors of positive self-rated health were non smoking (OR 1.5, p = 0.06) and non GMS eligibility (OR 1.99, p < 0.001). At four year follow-up, complete general practice data were available for 285 of 488 respondents with full recruitment data (58.4%). Increased GP utilisation pattern was predicted by baseline morbidity characteristics, though heavier male drinkers were less likely to attend.

Self-reported pre-pregnancy maternal body mass index and infant birth-weight.

This analysis examines the association between maternal characteristics, particularly body mass index (BMI) and infant birth weight in 1048 live infants. Mean reported pre pregnancy BMI of mothers was 23.74 kg/m2 (SD 4.21). The educational level of the mother's parents was independently associated with maternal BMI, those with higher educated parents having a lower reported BMI (F = 2.787, p = 0.029). Mean infant birth weight was 3493 g (SD 18.1) and there was a strong graduated relationship to estimated gestational age. In a sub-group of participating maternal grandmothers (n = 171), reported BMI was 26.7Kg/m2. The BMI of expectant mothers was significantly associated with their own mother's BMI. (r = 0.179, p = 0.005) in this sub-group. These preliminary findings, which will be investigated further with recorded height and weight information, suggest that familial factors are influential, perhaps through genetic predisposition or shared socio-cultural factors such as diet.

Primary care utilisation rates in pre-school children.

A key objective of the Lifeways cross generation cohort study is to examine health and healthcare, according to socio-economic indicators, during the first five years of life. GP contact details were available for 1032 children. 772 GPs in 589 practices were approached and data were obtained on 640 children (59% of original cohort). The mean follow-up time was 3.0 years (95% CI 2.5-3.5). 20.5% of children had a medical card. The mean GP consultation rate was 5.5 visits per child per year, 6.6 visits for children with a medical card and 5.1 for those without (95% CI 1.1 to 1.9) p = 0.001. 68 had a diagnosis of asthma; 19.10% with a medical card and 8.9% without (95% CI 3.0-17.5) p = 0.0001. 138 children had ever been admitted to hospital; 26.2% with a medical card and 21.0% without (95% CI -3.3% to 13.6%) p = 0.2. Incremental increases in parental income significantly decreased both the risk of asthma (p = 0.02) or hospital admission (p = 0.008).

Mothers' dietary patterns during pregnancy and risk of asthma symptoms in children at 3 years.

There is increasing evidence that dietary factors in early life play a role in the aetiology of childhood asthma. Our objective in this analysis was to assess whether maternal dietary patterns during pregnancy, as measured by a validated food frequency questionnaire, influenced general practitioner diagnosis of asthma by the age of 3 years in the Life-ways cohort of children. General Practice follow-up records were available for 631 of 1001 singleton children, twins having been excluded (63% follow-up rate). Overall 10.4% of children had diagnosed asthma, a prevalence rate comparable with other studies. In logistic regression models, based on quartiles of intake, which adjusted for maternal lifestyle and socio-economic circumstances, relatively higher maternal fruit and vegetable intake and oily fish consumption were associated with lower risk of children developing asthma, whilst those with relatively higher spreadable fat intake had a higher risk of asthma. These findings warrant further investigation as they imply an important role for maternal diet in childhood asthma, though the confounding effect of other social and lifestyle factors should be assessed as the children get older.

Do medical students with A-level mathematics have a better understanding of the principles behind evidence-based medicine?

With the advent of evidence-based medicine, medical students, doctors and other healthcare professionals are required to be more skilled in the interpretation and manipulation of numerical data. The authors observed that undergraduate students without A-level mathematics expressed concern as to their ability to cope with an epidemiology and biostatistics course. It was hypothesized that these anxieties reflected differences in attitudes to numerical manipulation rather than any real lack of competence. Mean exam performance scores were compared for 498 first-year medical students between 2000 and 2002 depending on whether the students did or did not have A-level mathematics. The data revealed no difference in performance. Students without mathematics A-level scored marginally worse (-1.1%, 95% CI -3.1% to 0.8%, p=0.20) but were no more likely to fail the exam (odds ratio=0.98, 95% CI 0.40 to 2.6, p=0.9). It is concluded that some students experience 'numerophobia'-- a perceived and, it is thought, disproportionate fear of numbers and simple mathematical manipulation. This may act as a psychological barrier for future evidence-based practitioners.

Homocysteine and ischaemic stroke in men: the Caerphilly study.

OBJECTIVE: To assess the risk of ischaemic stroke associated with total serum homocyst(e)ine (tHcy) concentration. DESIGN: Cohort study. SETTING: Caerphilly, South Wales PARTICIPANTS: 2254 men age 50 to 64 years recruited between 1984 and 1988. RESULTS: 107 men developed ischaemic stroke and mean follow up time was 10.2 years. There was no significant difference in mean serum total homocyst(e)ine levels between stroke cases (12.2 micromol 95% CI 11.6 to 13.1) and non-cases (11.7 micromol 95% CI 11.5 to 11.9) (p=0.14). There was no significant risk for a standard deviation increase in homocyst(e)ine (adjusted hazard ratio = 1.1, 95% CI 0.9 to 1.4). An interaction was observed between homocyst(e)ine and age at entry (p=0.003). The adjusted odds ratio comparing the top quintile of homocyst(e)ine with the rest was 2.5 (95% CI 1.0 to 6.2) for strokes occurring under 65 years and 0.5 (95% CI 0.2 to 1.3) at 65 years or older (p value for interaction =0.02). Risk also differed by blood pressure status. The adjusted hazard ratio for a standard deviation increase in homocyst(e)ine was 0.8, (95% CI 0.6 to 1.2) for normotensive men and 1.3 (95% CI 1.1 to 1.7) for hypertensive men (p value for interaction =0.01). CONCLUSIONS: Overall, there is no significant relation between homocyst(e)ine and ischaemic stroke in this cohort. However, its aetiological importance may be greater for premature ischaemic strokes (<65 years) and in hypertensive men.

Homocysteine and coronary heart disease in the Caerphilly cohort: a 10 year follow up.

OBJECTIVE: Prospective assessment of the risk of coronary heart disease associated with total serum homocyst(e)ine (homocysteine) concentration. DESIGN: Nested case-control study. SETTING: Caerphilly and surrounding villages in south Wales, UK. PARTICIPANTS: 2290 men who participated in phase II of the study in 1984. After a mean follow up of 10 years, 312 men developed coronary heart disease and were compared with 1248 randomly selected, age frequency matched controls. MAIN OUTCOME MEASURE: Acute myocardial infarction or death from coronary heart disease. RESULTS: The geometric mean serum homocysteine concentration was higher in cases (12.2 micromol/l, 95% confidence interval (CI) 11.8 to 12.6 micromol/l) than in controls (11.8 micromol/l, 95% CI 11.3 to 12.5 micromol/l) (p = 0.09). There was a graded increase in the odds ratio of coronary heart disease across quintiles of the homocysteine concentration distribution compared with the first (p = 0.04), which was attenuated when adjusted for confounding variables (p = 0.4). There was a small but non-significant increase in the adjusted odds ratio of coronary heart disease per standard deviation change in the log distribution of homocysteine concentration (OR = 1.07 (95% CI.93 to 1.24), p = 0.34). Comparing the top quintile of the homocysteine concentration with the remaining 80%, the adjusted odds ratio of coronary heart disease was 1.03 (95% CI 0.73 to 1.45) (p = 0.8) and comparing the top 5% with the remaining 95% it was 1.05 (95% CI 0.56 to 1.95) (p = 0.9). CONCLUSIONS: These findings do not support the hypothesis that a raised homocysteine concentration is a strong independent risk factor for coronary heart disease. Randomised controlled trials of homocysteine lowering treatment such as folic acid are needed before generalizing the early positive results of observational studies.

Hormone replacement therapy: a survey of Irish general practitioners.

We report findings of a cross-sectional postal survey of current prescribing practices of hormone replacement therapy (HRT) by Irish General Practitioners from a random sample of 600 Irish College of General Practitioners members. Median estimated prescribing rate of HRT was 17.5% (interquartile range 10 to 30%). The majority of General Practitioners would prescribe for the prevention of osteoporosis but there was some reluctance to prescribe solely for the prevention of CVD. Common cardiovascular conditions were regarded as contraindications to HRT by nearly one-third of GPs. Female GPs were more likely than males to request mammography (p < 0.002), to consider a first degree relative with breast cancer a contraindication (p < 0.01) and less likely to prescribe HRT for longer than 10 years (p < 0.0001), because of breast cancer risk. 78% of GPs would offer HRT to all eligible women. We conclude the estimated prescribing rate is comparable to rates in other developed countries.