Spatial variability of gastroschisis in Canada, 2006-2011: An exploratory analysis.

OBJECTIVES: Gastroschisis is a serious birth defect of the abdominal wall that is associated with mortality and significant morbidity. Our understanding of the factors causing this defect is limited. The objective of this paper is to describe the geographic variation in incidence of gastroschisis and characterize the spatial pattern of all gastroschisis cases in Canada between 2006 and 2011. Specifically, we aimed to ascertain the differences in spatial patterns between geographic regions and identify significant clusters and their location. METHODS: The study population included 641 gastroschisis cases from the Canadian Pediatric Surgery Network (CAPSNet) database, a population-based dataset of all gastroschisis cases in Canada. Cases were geocoded based on maternal residence. Using Statistics Canada live-birth data as a denominator, the total prevalence of gastroschisis was calculated at the provincial/territorial levels. Random effects logistic models were used to estimate the rates of gastroschisis in each census division. These rates were then mapped using ArcGIS. Cluster detection was performed using Local Indicators of Spatial Association (LISA). RESULTS: There is significant spatial heterogeneity of the rate of gastroschisis across Canada at both the provincial/territorial and census-division level. The Yukon, Northwest Territories and Prince Edward Island have higher overall rates of gastroschisis relative to other provinces/territories. Several census divisions in Alberta, Manitoba, Saskatchewan, Ontario, Northwest Territories and British Columbia demonstrated case "clusters", i.e., focally higher rates in discrete areas relative to surrounding areas. CONCLUSIONS: There is clear evidence of spatial variation in the rates of gastroschisis across Canada. Future research should explore the role of area-based variables in these patterns to improve our understanding of the etiology of gastroschisis.

Integrating environmental and human health databases in the great lakes basin: themes, challenges and future directions.

Many government, academic and research institutions collect environmental data that are relevant to understanding the relationship between environmental exposures and human health. Integrating these data with health outcome data presents new challenges that are important to consider to improve our effective use of environmental health information. Our objective was to identify the common themes related to the integration of environmental and health data, and suggest ways to address the challenges and make progress toward more effective use of data already collected, to further our understanding of environmental health associations in the Great Lakes region. Environmental and human health databases were identified and reviewed using literature searches and a series of one-on-one and group expert consultations. Databases identified were predominantly environmental stressors databases, with fewer found for health outcomes and human exposure. Nine themes or factors that impact integration were identified: data availability, accessibility, harmonization, stakeholder collaboration, policy and strategic alignment, resource adequacy, environmental health indicators, and data exchange networks. The use and cost effectiveness of data currently collected could be improved by strategic changes to data collection and access systems to provide better opportunities to identify and study environmental exposures that may impact human health.

The association between obstetrical interventions and late preterm birth.

OBJECTIVE: There is concern that obstetric interventions (prelabor cesarean section and induced delivery) are drivers of late preterm (LP) birth. Our objective was to evaluate the independent association between obstetric interventions and LP birth and explore associated independent maternal and fetal risk factors for LP birth. STUDY DESIGN: In this population-based cross-sectional study, the BORN Information System was used to identify all infants born between 34 and 40 completed weeks of gestation between 2005 and 2012 in Ontario, Canada. The association between obstetric interventions (preterm cesarean section and induced delivery) and LP birth (34 to 36 completed weeks' gestation vs 37 to 40 completed weeks' gestation) was assessed using generalized estimating equation regression. RESULTS: Of 917,013 births between 34 and 40 weeks, 49,157 were LP (5.4%). In the adjusted analysis, "any obstetric intervention" (risk ratio [RR], 0.65; 95% confidence interval [CI], 0.57-0.74), induction (RR, 0.71; 95% CI, 0.61-0.82) and prelabor cesarean section (RR, 0.66; 95% CI, 0.59-0.74) were all associated with a lower likelihood of LP vs term birth. Several independent potentially modifiable risk factors for LP birth were identified including previous cesarean section (RR, 1.28; 95% CI, 1.16-1.40), smoking during pregnancy (RR, 1.28; 95% CI, 1.21-1.36) and high material (RR, 1.1; 95% CI, 1.03-1.18) and social (RR, 1.09; 95% CI, 1.02-1.16) deprivation indices. CONCLUSION: After accounting for differences in maternal and fetal risk, LP births had a 35% lower likelihood of obstetric interventions than term births. Obstetric care providers may be preferentially avoiding induction and prelabor cesarean section between 34 and 37 weeks' gestation.

Impact of late preterm and early term infants on Canadian neonatal intensive care units.

OBJECTIVE: To examine the short-term morbidities, mortality, and use of neonatal intensive care unit (NICU) resources for late preterm, early term, and term infants. STUDY DESIGN: Infants born between 34 and 40 weeks of gestation and admitted to a Canadian NICU in 2010 were designated late preterm (340/7 to 366/7 weeks), early term (370/7 to 386/7 weeks), or term (390/7 to 406/7 weeks). Mortality, short-term morbidities, and resource utilization were compared between the three groups using chi-square tests and analysis of variance. RESULTS: Among 6,636 included infants, 44.2% (n = 2,935) were late preterm, 26.2% (n = 1,737) early term, and 29.6% (n = 1,964) term. Term infants were more likely to require resuscitation at birth and had lower Apgar scores than late preterm and early term infants (p < 0.001). Length of stay and need for respiratory support decreased with increasing gestational age; however, the proportion of hospital days that intensive care was required increased. CONCLUSION: The greatest impact of late preterm infants is on NICU bed occupancy, whereas for term infants it is on intensity of care. Early term infants experience greater rates of some complications than term, demonstrating that risk persists for these infants. These findings have important implications for NICU resource planning and practice.

Prediction of neonatal outcomes in extremely preterm neonates.

OBJECTIVE: To develop and validate a statistical prediction model spanning the severity range of neonatal outcomes in infants born at ≤ 30 weeks' gestation. METHODS: A national cohort of infants, born at 23 to 30 weeks' gestation and admitted to level III NICUs in Canada in 2010-2011, was identified from the Canadian Neonatal Network database. A multinomial logistic regression model was developed to predict survival without morbidities, mild morbidities, severe morbidities, or mortality, using maternal, obstetric, and infant characteristics available within the first day of NICU admission. Discrimination and calibration were assessed using a concordance C-statistic and the Cg goodness-of-fit test, respectively. Internal validation was performed using a bootstrap approach. RESULTS: Of 6106 eligible infants, 2280 (37%) survived without morbidities, 1964 (32%) and 1251 (21%) survived with mild and severe morbidities, respectively, and 611 (10%) died. Predictors in the model were gestational age, small (<10th percentile) for gestational age, gender, Score for Neonatal Acute Physiology version II >20, outborn status, use of antenatal corticosteroids, and receipt of surfactant and mechanical ventilation on the first day of admission. High model discrimination was confirmed by internal bootstrap validation (bias-corrected C-statistic = 0.899, 95% confidence interval = 0.894-0.903). Predicted probabilities were consistent with the observed outcomes (Cg P value = .96). CONCLUSIONS: Neonatal outcomes ranging from mortality to survival without morbidity in extremely preterm infants can be predicted on their first day in the NICU by using a multinomial model with good discrimination and calibration. The prediction model requires additional external validation.

Relationship of mode of conception and sex concordance with mortality/morbidity in preterm twins.

OBJECTIVE: To assess the association of mode of conception and sex concordance with neonatal outcomes in very preterm twins. STUDY DESIGN: Twin pairs born at gestational age ≤ 32 weeks and admitted to a Level 3 neonatal intensive care unit (NICU) in 2010-2011 were retrospectively identified from the Canadian Neonatal Network™ database. A composite outcome representing neonatal mortality or any severe morbidity (intraventricular hemorrhage grades ≥ 3 or periventricular leukomalacia, retinopathy of prematurity stages ≥ 3, bronchopulmonary dysplasia, or necrotizing enterocolitis stages ≥ 2) was compared between twins conceived using assisted reproduction technologies (ARTs) or spontaneously (SP), and tested for association with sex concordance in individual-level and pair-wise multivariable logistic regression analyses. RESULTS: Study subjects included 1,508 twins from 216 ART (53 [25%] male-male, 104 [48%] male-female, and 59 [27%] female-female) and 538 SP (192 [36%] male-male, 123 [23%] male-female, and 223 [41%] female-female) pairs. No statistically significant association was detected between mode of conception and the composite outcome of mortality/morbidities. The composite outcome was significantly higher in same-sex than in opposite-sex twins (OR = 1.68; 95% CI = [1.09, 2.59]). This relationship was most pronounced in ART pairs (OR = 2.25; 95% CI = [1.02, 4.98]), with increased rates in one or both twins from male-male versus opposite-sex ART pairs (OR = 3.0; 95% CI = [1.07, 8.36]). CONCLUSION: Same-sex pairing was associated with higher mortality/morbidities in very preterm twins admitted to the NICU, and can be used in clinical practice to identify twins at higher risk of adverse neonatal outcomes.

Association between congenital anomalies and area-level deprivation among infants in neonatal intensive care units.

OBJECTIVE: To examine the relationship between area-level material deprivation and the risk of congenital anomalies in infants admitted to neonatal intensive care units (NICUs) across Canada. STUDY DESIGN: The Canadian Neonatal Network database was used to identify admitted infants who had congenital anomalies between 2005 and 2009. The association between congenital anomalies and material deprivation quintile was assessed using logistic regression analysis. RESULTS: Of 55,961 infants admitted to participating NICUs during the study period, 6002 (10.7%) had major, 6244 (11.2%) had minor, and 43,715 (78.1%) had no anomalies. There were higher odds of major anomalies (odds ratio [OR] 1.13, 95% confidence interval [CI] 1.03 to 1.24) but not minor anomalies (OR 1.01, 95% CI 0.93 to 1.11) in the highest-deprivation areas as compared with the lowest-deprivation area of maternal residence. Analyses of groups of major anomalies revealed higher odds for chromosomal (OR 1.48, 95% CI 1.05 to 2.10) and multiple-systems (OR 1.40, 95% CI 1.14 to 1.71) anomalies in the highest-deprivation areas compared with the lowest-deprivation areas. CONCLUSION: There are socioeconomic inequalities in the risk of major congenital anomalies, especially chromosomal and multiple-systems anomalies, in the NICU population with the highest rates in the most socioeconomically deprived areas.

The changing epidemiology of preterm twins and triplets admitted to neonatal intensive care units in Canada, 2003 to 2008.

We describe trends in the rates of admission of preterm twin and triplet infants to neonatal intensive care units (NICUs) across Canada and compare their neonatal outcomes over a 6-year period. Temporal trends of admission rates for 5193 twins and triplets < 33 weeks' gestational age to participating NICUs in the Canadian Neonatal Network between 2003 and 2008 were assessed. Trends in infant outcomes were evaluated using logistic regression. The proportion of twins increased from 26.1 to 28.0 per 100 admissions between 2003 and 2008 (7% increase, p = 0.02). In contrast, the proportion of triplets decreased from 5.0 to 3.3 per 100 admissions (34% reduction, p = 0.04). These trends were significant in mothers ≥ 35 years of age. Neonatal outcomes improved for preterm twins (mortality, p < 0.01; survival without any major morbidity, p < 0.01; severe neurological injury, p = 0.02; and severe retinopathy of prematurity, p = 0.03). Similar improvements were observed for triplets, but the sample size was insufficient to reach statistical significance. The rate of NICU admissions for preterm twins at < 33 weeks' gestation has increased in recent years, whereas for triplets it has gradually declined. Neonatal outcomes of preterm twins improved over the study period.

The relationship between temperature and ambulance response calls for heat-related illness in Toronto, Ontario, 2005.

BACKGROUND: Concern over the adverse effects of heat on human health has led to numerous studies assessing the relationship between heat and mortality. Few studies have quantified the impact of heat on morbidity, including ambulance response calls. This study describes the association between temperature and ambulance response calls for heat-related illness (HRI) in Toronto, Ontario, Canada during the summer of 2005. METHODS: Data sources included daily temperature, relative humidity and humidex information from Environment Canada, and Medical Priority Dispatch System data from Toronto Emergency Medical Services. Time series and regression analyses were used to examine the relationship between daily temperature and ambulance response calls for HRI during the summer (1 June to 31 August) of 2005. RESULTS: In 2005, there were 201 ambulance response calls for HRI. On average, for every one degree increase in maximum temperature (°C) there was a 29% increase in ambulance response calls for HRI (p<0.0001). For every one degree increase in mean temperature (°C) there was a 32% increase in ambulance response calls for HRI (p<0.0001). CONCLUSIONS: Given these associations, we urge further exploration of ambulance response calls as a source of HRI morbidity data particularly given the increasing health concerns associated with climate change.

Effectiveness of public health interventions in reducing morbidity and mortality during heat episodes: a structured review.

Increasing concern over the impact of hot weather on health has fostered the development of public health interventions to reduce heat-related health impacts. However, evidence of the effectiveness of such interventions is rarely cited for justification. Our objective was to review peer-reviewed and grey literature evaluating interventions aimed at reducing morbidity and/or mortality in populations during hot weather episodes. Among studies considering public risk perceptions, most respondents were aware when an extreme heat episode was occurring but did not necessarily change their practices, primarily due to a lack of self-perception as vulnerable and confusion about the appropriate actions to be taken. Among studies of health outcomes during and following heat episodes, studies were suggestive of positive impacts in reducing morbidity and mortality. While the limited evaluative work to date suggests a positive impact of public health interventions, concern persists about whether the most vulnerable groups, like the elderly and homeless, are being adequately reached.

Climate change and health in british columbia: projected impacts and a proposed agenda for adaptation research and policy.

This is a case study describing how climate change may affect the health of British Columbians and to suggest a way forward to promote health and policy research, and adaptation to these changes. After reviewing the limited evidence of the impacts of climate change on human health we have developed five principles to guide the development of research and policy to better predict future impacts of climate change on health and to enhance adaptation to these change in BC. We suggest that, with some modification, these principles will be useful to policy makers in other jurisdictions.

Temporal and spatial variation of heat-related illness using 911 medical dispatch data.

BACKGROUND: The adverse effect of hot weather on health in urban communities is of increasing public health concern, particularly given trends in climate change. OBJECTIVES: To demonstrate the potential public health applications of monitoring 911 medical dispatch data for heat-related illness (HRI), using historical data for the summer periods (June 1-August 31) during 2002-2005 in Toronto, Ontario, Canada. METHODS: The temporal distribution of the medical dispatch calls was described in relation to a current early warning system and emergency department data from the National Ambulatory Care Reporting System (NACRS). Geospatial methods were used to map the percentage of heat-related calls in each Toronto neighborhood over the study period. RESULTS: The temporal pattern of 911 calls for HRI was similar, and sometimes peaked earlier, than current heat health warning systems (HHWS). The pattern of calls was similar to NACRS HRI visits, with the exception of 2005 where 911 calls peaked earlier. Areas of the city with a relatively higher burden of HRI included low income inner-city neighborhoods, areas with high rates of street-involved individuals, and areas along the waterfront which include summer outdoor recreational activities. CONCLUSIONS: Identifying the temporal trends and geospatial patterns of these important environmental health events has the potential to direct targeted public health interventions to mitigate associated morbidity and mortality.

Development of a surveillance case definition for heat-related illness using 911 medical dispatch data.

OBJECTIVES: The adverse effects of hot weather on public health are of increasing concern. A surveillance system using 911 medical dispatch data for the detection of heat-related illness (HRI) could provide new information on the impact of excessive heat on the population. This paper describes how we identified medical dispatch call codes, called "determinants", that could represent HRI events. METHODS: Approximately 500 medical dispatch determinants were reviewed in focus groups composed of Emergency Medical Services (EMS) paramedics, dispatchers, physicians, and public health epidemiologists. Each group was asked to select those determinants that might adequately represent HRI. Selections were then assessed empirically using correlations with daily mean temperature over the study period (June 1-August 31,2005). RESULTS: The focus groups identified 12 determinant groupings and ranked them according to specificity for HRI. Of these, "Heat/cold exposure" was deemed the most specific. The call determinant groupings with the clearest positive associations with daily mean temperature empirically were "Heat/cold exposure" (Spearman's correlation coefficient (SCC) 0.71, p < 0.0001) and "Unknown problem (man down)" (SCC 0.21, p = 0.04). Within each grouping, the determinant "Unknown status (3rd party caller)" showed significant associations, SCC = 0.34 (p = 0.001) and SCC = 0.22 (p = 0.03) respectively. CONCLUSIONS: Clinically-informed expertise and empirical evidence both contributed to identification of a group of 911 medical dispatch call determinants that plausibly represent HRI events. Once evaluated prospectively, these may be used in public health surveillance to better understand environmental health impacts on human populations and inform targeted public health interventions.