A population based time series analysis of asthma hospitalisations in Ontario, Canada: 1988 to 2000.

BACKGROUND: Asthma is a common yet incompletely understood health problem associated with a high morbidity burden. A wide variety of seasonally variable environmental stimuli such as viruses and air pollution are believed to influence asthma morbidity. This study set out to examine the seasonal patterns of asthma hospitalisations in relation to age and gender for the province of Ontario over a period of 12 years. METHODS: A retrospective, population-based study design was used to assess temporal patterns in hospitalisations for asthma from April 1, 1988 to March 31, 2000. Approximately 14 million residents of Ontario eligible for universal healthcare coverage during this time were included for analysis. Time series analyses were conducted on monthly aggregations of hospitalisations. RESULTS: There is strong evidence of an autumn peak and summer trough seasonal pattern occurring every year over the 12-year period (Fisher-Kappa (FK) = 23.93, p > 0.01; Bartlett Kolmogorov Smirnov (BKS) = 0.459, p < 0.01). This pattern was observed in both sexes. However, young males (0-4 years) were hospitalised at two to three times the rate of females of the same age. Rates were much lower in the older age groups. A downward trend in asthma hospitalisations was observed in the total population over the twelve-year period (beta = -0.980, p < 0.01). CONCLUSIONS: A clear and consistent seasonal pattern was observed in this study for asthma hospitalisations. These findings have important implications for the development of effective management and prevention strategies.

Perceptions and experiences of environmental health risks among new mothers: a qualitative study in Ontario, Canada.

There is a growing awareness and concern in contemporary societies about potential health impacts of environmental contaminants on children. Mothers are traditionally more involved than other family members in managing family health and household decisions and thus targeted by public health campaigns to minimise risks. However little is known about how new mothers perceive and experience environmental health risks to their children. In 2010, we undertook a parallel case study using qualitative, in-depth interviews with new mothers and focus groups with public health key informants in two Public Health Units in Ontario Province, Canada. We found that the concern about environmental hazards among participants ranged from having no concerns to actively incorporating prevention into daily life. Overall, there was a common perception among participants that many risks, particularly in the indoor environment, were controllable and therefore of little concern. But environmental risks that originate outside the home were viewed as less controllable and more threatening. In response to such threats, mothers invoked coping strategies such as relying on the capacity of children's bodies to adapt. Regardless of the strategies adopted, actions (or inactions) were contingent upon active information seeking. We also found an optimistic bias in which new mothers reported that other children were at greater risk despite similar environmental circumstances. The findings suggest that risk communication experts must attend to the social and environmental contexts of risk and coping when designing strategies around risk reducing behaviours.

An exploratory spatial analysis of pneumonia and influenza hospitalizations in Ontario by age and gender.

Pneumonia and influenza represent a significant public health burden in Canada and abroad. Knowledge of how this burden varies geographically provides clues to understanding the determinants of these illnesses, and insight into the effective management of health-care resources. We conducted a retrospective, population-based, ecological-level study to assess age- and gender-specific spatial patterns of pneumonia and influenza hospitalizations in the province of Ontario, Canada from 1992 to 2001. Results revealed marked variability in hospitalization rates by age, as well as clear and statistically significant patterns of high rates in northern rural counties and low rates in southern urban counties. A moderate yet significant level of positive spatial autocorrelation (Moran's I=0.21, P<0.05) was found in the global data, with significant, age-specific clusters of high values or 'hot spots' identified in several northern counties. Findings illustrate the need for geographically focused prevention strategies, and resource and service allocation policies informed by regional and population-specific demands.

Interactions of viral pathogens on hospital admissions for pneumonia, croup and chronic obstructive pulmonary diseases: results of a multivariate time-series analysis.

Co-circulation of respiratory syncytial virus (RSV) and influenza has made the partitioning of morbidity and mortality from each virus difficult. Given the interaction between chronic obstructive lung disease (COPD) and pneumonia, often one can be mistaken for the other. Multivariate time-series methodology was applied to examine the impact of RSV and influenza on hospital admissions for bronchiolitis, pneumonia, and COPD. The Granger Causality Test, used to determine the causal relationship among series, showed that COPD and pneumonia are not influenced by RSV (P=0.2999 and 0.7725), but RSV does influence bronchiolitis (P=0.0001). Influenza was found to influence COPD, pneumonia, and bronchiolitis (P<0.0001). The use of multivariate time series and Granger causality applied to epidemiological data clearly illustrates the significant contribution of influenza and RSV to morbidity in the population.